QUESTION:

How do earth scientists use a high-speed camera. For instance lets say you wanted to study the movement of a glacier. How would you go about doing that?

REPLY:

Great question! And I certainly am qualified to answer that question since I and my Volcano Watch International team member Bob Benward have created high-speed movies of volcanoes erupting! For instance, In February 2003, Bob and I set up a 0.0003 lux CCD video camera to expand and support our visual coverage of the erupting Soufriere Hills volcano on Montserrat in the West Indies. The camera took frames every 8 seconds, which were relayed to a digital video data recorder; each frame was saved as a JPEG, which could be played back at 6 minutes per day for 12 days.

QUESTION:

How is an alligator affected by the depleting of the ozone layer? Does this affect the color of their skin and when it does, does it change color?

REPLY:

Alligators are a specialty of mine. While it’s true that the International Union for the Conservation of Nature — which has set up the Declining Amphibians Population Task Force — are trying to find reasons for mysterious population decreases in not only amphibians but in reptile, like alligators, they have no definitive answers. They are investigating, in part, the thinning ozone layer as a possible cause, but this, I believe, is way off mark!

The most possible, and probable cause is pesticides from nearby farms and perhaps acid rain.

For instance, consider the fate of the alligators of Lake Apopka, which is a few miles from Disney World in Central Florida. Alligators were once plentiful there, but in recent years, their numbers have dropped significantly — to 10 percent of their 1980 numbers. According to the National Federation of Wildlife, the plight of Lake Apopka’s alligators is an extraordinary case of what some scientists say is a widespread problem. University of Florida scientists attribute the decline to an accident at the Tower Chemical Company facility next to the lake’s waters in 1980. The company spilled the pesticide kelthane (which contains DDT) and sulfuric acid. The lake also receives pesticide runoff from nearby citrus farms.

The idea that alligators, which have been around much longer than man — some 200 million years — are being greatly and suddenly affected solely by a trace depletion of ozone borders on pseudoscience. We know relatively very little about the ozone layer today, let alone how dense or anemic it was millions of years ago. Obviously, alligators have remained relatively unchanged and unchallenged over the millions of years — until humans arrived on the scene with guns and toxic chemicals. If you want to find a reason for declining alligator populations or deformities, I believe you need not look to the skies. The fault is here, in the water, near toxic waste dumps and runoffs.

QUESTION:

I need information on where I can find pink snow.

REPLY:

Pink snow can appear on high mountaintops that are usually or perpetually covered in snow. The cause of the reddish coloration is a bloom of algal cells — each about 30 micrometers in diameter. The blooms can be most dramatic during late spring and summer. The concentrations of these cells is so profuse that a teaspoon of melted snow in these regions can contain more than a million snow algae cells. The more compact the snow, the more intense the reddish color. Each spherical cell is approximately 30 micrometers in diameter, about four times the diameter of a human red blood cell.

These pink snow patches baffled explorers and naturalists for thousands of years — including the philosopher Aristotle! At least 60 different species of snow algae have been identified in the western United States. By the way, the scientific surname of this cold-loving algae is nivalis — it’s from a Latin word that refers to snow.

QUESTION:

I need to know if you know what major diseases immigrants are tested for before they enter the U.S. (besides TB).

REPLY:

First, you’re right, before 1924, every legal immigrant was examined for infectious diseases upon arrival in the US and tested for tuberculosis. According to Dr. Madeleine Cosman, “That was powerful incentive for each newcomer to make heroic efforts to appear healthy.” Alas, today, she says, legal immigrants must demonstrate that they are free of communicable diseases and drug addiction to qualify for lawful permanent residency Green Cards. Of course, the larger problem are the diseases brought into this country by unchecked illegal aliens. She also writes that “if we catch and detain a sick Illegal Alien, who after examination by physicians in a detention center proves to have a serious disease, we keep him! Foolish compassion makes us fear that his home country has neither adequate medical resources nor modern wonder drugs. So we release sick Illegal Aliens to the American streets, to infect others if their diseases are contagious, or we place them in our Medicaid program where we pay for their expensive treatments.” You can read more at http://www.rense.com/general64/ill.htm.

Meanwhile, some countries, like Great Britain, are lobbying for a bill that would require immigrants wanting to live in that country to undergo tests for HIV, tuberculosis and hepatitis B.

QUESTION:

What came first the chicken or the egg?

REPLY:

The following is from “Chicken Facts:”

“According to National Geographic, scientists have settled the old dispute over which came first — the chicken or the egg. They say that reptiles were laying eggs thousands of years before chickens appeared, and the first chicken came from an egg laid by a bird that was not quite a chicken. That seems to answer the question. The egg came first. Source: *Knowledge in a Nutshell*”

QUESTION:

How was the moon formed?

REPLY:

Despite earlier thinking, the Moon did not pop out of Earth’s oceans. The leading theory today is that about 4.5 billion years ago a Mars-sized body slammed into primordial Earth. The resulting debris cloud, which was comprised of particles from both the Earth and the impacting body, was captured by Earth’s gravity and accumulated to form the Moon.

QUESTION:

Can chickens fly?

REPLY:

Can chickens fly. Well, yes they can . . . for short distances. Kathy Rogers, a wildlife rehabilitator at Samuell Farm, in Dallas, Texas, calls chickens “spurt flyers,” meaning they will flap up to a low tree or fence post to roost for the night or when they feel in danger.

The “law,” however is that the bigger the bird the bigger the belly, and the less likely a chicken is to fly. The reason we don’t see chickens “flying the coop” (so to say) is because we breed them to be BIG — so they can lay eggs or are “meaty” for consumption.

But Rogers says that even the fittest of chickens would never fly for any distance.

You might enjoy going to this web site: Chicken Facts:

http://www.vfr.net/~tbruce/facts.html. There you will learn, among many other things:

* Fact – The longest distance flown by any chicken is 301 1/2 feet. (That’s as the crow flies).

QUESTION:

My question is about the bald eagle. I have been watching a familiar bald eagle (in a zoo) who is getting to be about 25 or so years old. His beak appears to be getting paler – no longer a bright yellow, but a pale buttery color. Is this a sign of age?

REPLY:

You are absolutely right. The beak . . . and eyes . . . of an immature eagle are dark. As the Bald Eagle matures — around the ages of four to five — the bird begins to get its white tail and head, and the eyes and beak begin to turn yellow. Just as you observed!

QUESTION:

I live in the Northeast. In the Autumn, after all of the leaves fall from the trees and it snows, why don’t people suffocate because there are no leaves around producing oxygen through photosynthesis?

REPLY:

I’m sure you’ve heard of “Think Globally, Act Locally!” Well, think globally.

In one year, an average tree inhales 26 pounds of carbon dioxide and exhales enough oxygen to keep a family of four breathing for a year. And yes, there are lots of trees in New England, and they do produce a lot of oxygen when they photosynthesize. But New England is such a small place on the global scale.

In fact, did you know that it’s the rain forests — places that stay green all year round — that generate about 40 percent of the world’s oxygen? Not only that, but trees are not the only source of oxygen. For instance, bacteria and a few other organisms are photosynthetic.

Oxygen is also stored in Earth’s waters and soil, as well as in animal tissue and more! All of these sources can replenish oxygen in our atmosphere by simply changing states.

On a global scale, about a trillion kilograms of oxygen are produced by photosynthesis per day. The vast majority of this process happens in our oceans mostly by bacterium or a blue-green alga! We humans, on the other hand, convert about the same amount of oxygen to carbon dioxide.

QUESTION:

Why are glaciers called rivers of ice?

REPLY:

First, some rivers, as you may know, originate from snowcapped mountains. As the snow warms, it melts. Gravity then forces the water down the mountain. The water takes the course of least resistance and flows in a constant rush down slope, usually in steep-sided valleys. These are glacial source-fed rivers.

Actually, glaciers do not need slopes to flow. Like dense molten lava, the front of the glacier advances by the continuing accumulation of new material at their point of origin. That pile up causes pressure on the layers of material below. In the case of ice, the pressure heats the ice and forcing the lower layers to slowly creep forward like a viscous fluid. Over time the glacier extends down the mountain, following the curving valleys like a river. So a glacier is, in a sense an enormous, slowly advancing frozen river.

QUESTION:

What are some myths and legends for Mount Pinatubo?

REPLY:

Mount Pinatubo is a great volcano on Luzon Island in the Philippines. The region’s aboriginal people, the Ayta’s, or Aeta’s, see Mount Pinatubo as the dwelling place of Apo Namalyari, the One who creates, the One who makes the whole of creation grow and live. Pinatubo is, to them, a sacred mountain where the dead Aetas go. Today it is still the home of their spiritual heritage and the homeland of the spirits of their ancestors.

QUESTION:

In the formation of color in a blue painted object illuminated with white light, how does the formation mechanism differ from that causing the blue in blue sky?

REPLY:

The quick response to what I believe you are asking is that painted blue object is a product of color absorption. All objects contain atoms which are capable of absorbing one or more frequencies of light and reflecting all others. The color we ultimately see depends on what colors are absorbed and which mixture of colors are reflected to our eyes…

As for the sky, it is blue because air molecules effectively scatter blue wavelengths of light.

QUESTION:

What is sonoluminesence?

REPLY:

Sonoluminescence, also called a mysterious “star in a jar” is, essentially, a microscopic bubble suspended in a jar of water by acoustic waves. The force of the oscillating waves stretch and compress the bubble some 30,0000 times per second, generating temperatures hotter than the Sun’s surface. A faint flash of light (the luminescence) accompanies each cycle, which lasts only 30 trillionths of a second.

QUESTION:

What is a mummy?

REPLY:

Most people believe mummies are bodies wrapped in bandages that lie buried in tombs beneath the ancient sands of Egypt. And while this is true for many mummies found in Egypt, not all mummies are wrapped in bandages.

Cutting to the quick, a mummy is is the deceased body of a person (or an animal) whose skin and flesh have been preserved after death. The preservation can be intentional or accidental. Many of the mummies of Egypt, for instance, have been deliberately embalmed to preserve the body’s soft tissue. Other mummified bodies have been accidentally preserved (without being wrapped in bandages or embalmed) by extreme hot, cold, or airless environments.

Have you ever heard of Ötzi the Ice Man? He was found in 19991, high in a snowfield in the Alps. His body is estimated to be about 5,200 years old. His skin tissue was kept virtually intact by the extreme cold at altitude. Then there’s Tollund Man — a 2,100-year-old body found in a peat bog in Denmark. Some bodies have been found in cold, dry caves, whose conditions helped to slow the rate of tissue deterioration.

QUESTION:

What are some of the common characteristics we share with a beetle?

REPLY:

Well, off the top of my head, I’d have to say that the most important thing that they have with humans, and maybe the only thing, is that they use their five senses to survive!

QUESTION:

Who created the periodic table?

REPLY:

The first periodic table of elements was created by Dimitri Ivanovich Mendeleev (1834 -1907). It was his method of classifying the basic building blocks of matter. I say it was the “original” periodic table because in Mendeleev’s day, only 60 of the more than 110 elements were known. In a chemistry book Menedleev published in 1905, he writes the following about the reason he created the table:

“I began to look about and write down the elements with their atomic weights and typical properties, analogous elements and like atomic weights on separate cards, and this soon convinced me that the properties of elements are in periodic dependence upon their atomic weights.”

QUESTION:

Which scientist / inventor created “for every action there is an opposite and equal reaction”?

REPLY:

That’s Sir Isaac Newton’s Third Law of Motion: For every action there is an opposite and equal reaction. It explains, for example, why rockets fly! When hot gases push out from the bottom of the rocket, the rocket is hurtled skyward with a force equal and opposite to the force of the gas that’s pushing earthward.

QUESTION:

How far away is the Moon?

REPLY:

That’s a good question — one that is not as simple as it sounds. The Moon’s distance varies as it orbits the Earth. This is due to the fact that the Moon’s orbit is not circular but elliptical. When the Moon is closest to the Earth it is at a point called perigee. When it is farthest from Earth it is called at a point called apogee. When the Moon reaches perigee, its distance is 363,300 kilometers (225,755 miles). When the Moon is at apogee it is 405,500 km (251,978 miles) distant. The Moon’s average or mean distance from Earth is 384,400 km (238,866 miles).

QUESTION:

What are Saturn’s rings made of?

REPLY:

Great question! About a century and a half ago, some Harvard astronomers believed the rings were fluid, but today we know they are comprised of tiny pieces of rock and ice that form a complex system of rings around the planet.

Saturn has three major rings — Rings A, B, and C (from the outside in, respectively) and several minor ones. The Cassini spacecraft determined that the particles in the major rings range from a few centimeters in diameter to 10 meters in diameter, though there is no typical size. Besides, the particles are most likely colliding with one another. The A and B rings are very slightly reddish, which may be evidence of some organic materials mixed in as well.

In essence, the rings are like a shattered comet. The Cassini spacecraft also recently discovered large amounts of dark material, or “dirt,” within the gap (Called the Cassini Division) between Saturn’s A and B rings. This dark matter appears remarkably similar to that found on one of Saturn’s moons, Phoebe. NASA scientists say that these dark particles refuel the theory that Saturn’s rings might be the remnants of an icy moon that has been ripped apart by tidal forces.

By the way, Cassini also detected large quantities of oxygen at the edge of the rings, which may have resulted from a collision of an icy body that occurred as recently as several months ago.

QUESTION:

What is dog feces and what causes the smelly gas?

REPLY:

According to Medfriendly.com:

Dog feces are mostly made of water (about 75%). The rest is made of dead bacteria that help to digest the food, living bacteria, protein, undigested food residue (known as fiber), waste material from food, cellular linings, fats, salts, and substances released from the intestines (such as mucus) and the liver. Although feces are made up of about 75% water, this number varies from animal to animal, depending on how long the feces stay in the intestine. Since the intestines absorb water from the feces, diarrhea (poop that passes quickly through the intestines) will contain more water and retained feces (which stay in the intestines for a longer amount of time) will contain less.

The bacteria inside of the feces is what makes them smell so bad. (That’s the gas). Specifically, the bacteria produce various compounds and gases that lead to the infamous smell of feces. It’s hard to say what gases are being released because that depends on what you feed your dog. Generally speaking, feces will smell worse if your animal consumes food or liquids with many artificial flavors or chemicals in them. The bad smell of feces will usually be reduced by eating more natural foods that do not contain any artificial flavors or chemicals. Remember, however, that these are general guidelines. The only way to know for sure is to monitor the smell of feces depending on the types of foods in the diet and to see if the smell changes when certain foods are removed or added.

QUESTION:

Why do we not see galaxies and stars in the background when NASA shows an astronaut outside the Space Shuttle?

REPLY:

Great question. The answer is quite simple. It has to do with the limitations of a camera lens and the great dynamic range in contrast between the extremely bright astronaut or spacecraft and the extreme relative dimness of starlight. The camera takes very short exposures, which are not long enough to capture the star-filled sky. For instance, if you own a camera, take it outside, hold it up to the sky and take a 1/125-second exposure. When you get the film developed, you’ll see only darkness — not infinite starlight. As for galaxies — there are only a couple bright enough to be seen with the naked eye. All the images you see from space — like those taken with the HST– that are filled with starlight and galaxies is a product of a large-aperture telescope, sensitive electronic cameras, and precise guiding via satellite links. All these images are taken looking away from any bright objects.

QUESTION:

What are odds that a black hole will suck up the Earth? And what will happen if a black hole really sucks up the Earth?

REPLY:

First, the odds that the Earth will be sucked into a black hole are essentially zero. Black holes are formed by stars much more massive than our Sun. When these very massive stars die, their interiors collapse into an infinite point, beyond which, we can only theorize what will happen.

When our Sun dies, it will become what is known as a planetary nebula. The outer shell of gas will expand about 10 miles per second away from a collapsed core called a white dwarf — a star with the size of the Earth but so compressed that a tablespoonful of its matter would weigh 15 tons! The outer shell will swell to encompass our Solar System. After 5 billion years, that white dwarf will turn into a black and lifeless cinder. But don’t worry. By then, us humans will have developed ways to travel to other suns and inhabit other planets. (I’ll buy you a cup of coffee if we don’t.)

If a black hole were to “suck up” the Earth, well, the Earth may emerge in another dimension, or in another region of curved space — that’s after it exists the hypothetical “white hole.” Take a sheet of paper and curl it into a “C.” Imagine a black hole occurs on the top of the C. Now imagine a tube connecting it to the bottom of the C — that’s where you could find your white hole.

QUESTION:

Why does a boat float higher in salt water? Please explain in first grade terminology.

REPLY:

Floating is a common term for what is known as “Buoyancy.” So, to keep it simple I’m going to call buoyancy . . . floating. Rather than thinking of a boat in water as a heavy thing that can sink. Think of the water below pushing up on the boat. The reason something floats is because the water beneath it is pushing up on it. The larger the base of the boat the more water can push up on it and the better it can float. So think of floating as an upward force. Now, salt water is denser (heavier) than fresh water. So think of salt water as being stronger than fresh water, in that it can push up on an object harder or with more force. Think of a 90-pound person trying to bench press, say 50 pounds, as opposed to someone who is 150 pounds.

QUESTION:

How do I become an astronaut?

REPLY:

This answer comes straight from the horse’s mouth…NASA! And it’s a long answer.

****

We will assume you mean a NASA astronaut, since it’s probably impossible for a non-Russian to get into the cosmonaut corps (paying passengers are not professional cosmonauts), and the other nations have so few astronauts (and fly even fewer) that you’re better off hoping to win a lottery. Becoming a shuttle pilot requires lots of fast-jet experience, which means a military flying career; forget that unless you want to do it anyway. So you want to become a shuttle “mission specialist.”

If you aren’t a US citizen, become one; that is a must. After that, the crucial thing to remember is that the demand for such jobs vastly exceeds the supply. NASA’s problem is not finding qualified people, but thinning the lineup down to manageable length.

It is not enough to be qualified; you must avoid being *dis*qualified for any reason, many of them in principle quite irrelevant to the job. Get a Ph.D. Specialize in something that involves getting your hands dirty with equipment, not just paper and pencil. Forget computer programming entirely; it will be done from the ground for the foreseeable future. Degree(s) in one field plus work experience in another seems to be a frequent winner.

Be in good physical condition, with good eyesight. (DO NOT get a radial keratomy or similar hack to improve your vision; nobody knows what sudden pressure changes would do to RKed eyes, and long-term effects are poorly understood. For that matter, avoid any other significant medical unknowns.) If you can pass a jet-pilot physical, you should be okay; if you can’t, your chances are poor.

Practice public speaking, and be conservative and conformist in appearance and actions; you’ve got a tough selling job ahead, trying to convince a cautious, conservative selection committee that you are better than hundreds of other applicants. (And, also, that you will be a credit to NASA after you are hired: public relations is a significant part of the job, and NASA’s image is very prim and proper.) The image you want is squeaky-clean workaholic yuppie. Remember also that you will need a security clearance at some point, and Security considers everybody guilty until proven innocent. Keep your nose clean.

Get a pilot’s license and make flying your number one hobby; experienced pilots are known to be favored even for non-pilot jobs. Work for NASA; of 45 astronauts selected between 1984 and 1988, 43 were military or NASA employees, and the remaining two were a NASA consultant and Mae Jemison (the first black female astronaut). If you apply from outside NASA and miss, but they offer you a job at NASA, ***TAKE IT***; sometimes in the past this has meant “you do look interesting but we want to know you a bit better first”. Think space: they want highly motivated people, so lose no chance to demonstrate motivation.

Keep trying. Many astronauts didn’t make it the first time.

NASA
National Aeronautics and Space Administration
Lyndon B. Johnson Space Center
Houston, Texas

Announcement for Mission Specialist and Pilot Astronaut Candidates

======================================================

Astronaut Candidate Program

The National Aeronautics and Space Administration (NASA) has a need for Pilot Astronaut Candidates and Mission Specialist Astronaut Candidates to support the Space Shuttle Program. NASA is now accepting on a continuous basis and plans to select astronaut candidates as needed.

Persons from both the civilian sector and the military services will be considered. All positions are located at the Lyndon B. Johnson Space Center in Houston, Texas, and will involved a 1-year training and evaluation program.

Space Shuttle Program Description

The numerous successful flights of the Space Shuttle have demonstrated that operation and experimental investigations in space are becoming routine. The Space Shuttle Orbiter is launched into, and maneuvers in the Earth orbit performing missions lasting up to 30 days. It then returns to earth and is ready for another flight with payloads and flight crew.

The Orbiter performs a variety of orbital missions including deployment and retrieval of satellites, service of existing satellites, operation of specialized laboratories (astronomy, earth sciences, materials processing, manufacturing), and other operations. These missions will eventually include the development and servicing of a permanent space station. The Orbiter also provides a staging capability for using higher orbits than can be achieved by the Orbiter itself. Users of the Space Shuttle’s capabilities are both domestic and foreign and include government agencies and private industries. The crew normally consists of five people – the commander, the pilot, and three mission specialists. On occasion additional crew members are assigned. The commander, pilot, and mission specialists are NASA astronauts.

Pilot Astronaut

Pilot astronauts server as both Space Shuttle commanders and pilots. During flight the commander has onboard responsibility for the vehicle, crew, mission success and safety in flight. The pilot assists the commander in controlling and operating the vehicle. In addition, the pilot may assist in the deployment and retrieval of satellites utilizing the remote manipulator system, in extravehicular activities, and other payload operations.

Mission Specialist Astronaut

Mission specialist astronauts, working with the commander and pilot, have overall responsibility for the coordination of Shuttle operations in the areas of crew activity planning, consumables usage, and experiment and payload operations. Mission specialists are required to have a detailed knowledge of Shuttle systems, as well as detailed knowledge of the operational characteristics, mission requirements and objectives, and supporting systems and equipment for each of the experiments to be conducted on their assigned missions. Mission specialists will perform extravehicular activities, payload handling using the remote manipulator system, and perform or assist in specific experimental operations.

Astronaut Candidate Program

Basic Qualification Requirements

Applicants MUST meet the following minimum requirements prior to submitting an application.

Mission Specialist Astronaut Candidate:

1. Bachelor’s degree from an accredited institution in engineering, biological science, physical science or mathematics. Degree must be followed by at least three years of related progressively responsible, professional experience. An advanced degree is desirable and may be substituted for part or all of the experience requirement (master’s degree = 1 year, doctoral degree = 3 years). Quality of academic preparation is important.

2. Ability to pass a NASA class II space physical, which is similar to a civilian or military class II flight physical and includes the following specific standards:

Distant visual acuity: 20/150 or better uncorrected, correctable to 20/20, each eye.

Blood pressure: 140/90 measured in sitting position.

3. Height between 58.5 and 76 inches.

Pilot Astronaut Candidate:

1. Bachelor’s degree from an accredited institution in engineering, biological science, physical science or mathematics. Degree must be followed by at least three years of related progressively responsible, professional experience. An advanced degree is desirable. Quality of academic preparation is important.

2. At least 1000 hours pilot-in-command time in jet aircraft. Flight test experience highly desirable.

3. Ability to pass a NASA Class I space physical which is similar to a military or civilian Class I flight physical and includes the following specific standards:

Distant visual acuity: 20/50 or better uncorrected correctable to 20/20, each eye.

Blood pressure: 140/90 measured in sitting position.

4. Height between 64 and 76 inches.

Citizenship Requirements

Applications for the Astronaut Candidate Program must be citizens of the United States.

**Note on Academic Requirements

Applicants for the Astronaut Candidate Program must meet the basic education requirements for NASA engineering and scientific positions — specifically: successful completion of standard professional curriculum in an accredited college or university leading to at least a bachelor’s degree with major study in an appropriate field of engineering, biological science, physical science, or mathematics.

The following degree fields, while related to engineering and the sciences, are not considered qualifying:

– Degrees in technology (Engineering Technology, Aviation Technology, Medical Technology, etc.)

– Degrees in Psychology (except for Clinical Psychology, Physiological Psychology, or Experimental Psychology which are qualifying).

– Degrees in Nursing.

– Degrees in social sciences (Geography, Anthropology, Archaeology, etc.)

– Degrees in Aviation, Aviation Management or similar fields.

Application Procedures

Civilian

The application package may be obtained by writing to:

NASA Johnson Space Center
Astronaut Selection Office
ATTN: AHX
Houston, TX 77058

Civilian applications will be accepted on a continuous basis. When NASA decides to select additional astronaut candidates, consideration will be given only to those applications on hand on the date of decision is made. Applications received after that date will be retained and considered for the next selection. Applicants will be notified annually of the opportunity to update their applications and to indicate continued interest in being considered for the program. Those applicants who do not update their applications annually will be dropped from consideration, and their applications will not be retained. After the preliminary screening of applications, additional information may be requested for some applicants, and person listed on the application as supervisors and references may be contacted.

Active Duty Military

Active duty military personnel must submit applications to their respective military service and not directly to NASA. Application procedures will be disseminated by each service.

Selection

Personal interviews and thorough medical evaluations will be required for both civilian and military applicants under final consideration. Once final selections have been made, all applicants who were considered will be notified of the outcome of the process.

Selection rosters established through this process may be used for the selection of additional candidates during a one year period following their establishment.

General Program Requirements

Selected applicants will be designated Astronaut Candidates and will be assigned to the Astronaut Office at the Johnson Space Center, Houston, Texas. The astronaut candidates will undergo a 1 year training and evaluation period during which time they will be assigned technical or scientific responsibilities allowing them to contribute substantially to ongoing programs. They will also participate in the basic astronaut training program which is designed to develop the knowledge and skills required for formal mission training upon selection for a flight. Pilot astronaut candidates will maintain proficiency in NASA aircraft during their candidate period.

Applicants should be aware that selection as an astronaut candidate does not insure selection as an astronaut. Final selection as an astronaut will depend on satisfactory completion of the 1 year training and evaluation period. Civilian candidates who successfully complete the training and evaluation and are selected as astronauts will become permanent Federal employees and will be expected to remain with NASA for a period of at least five years. Civilian candidates who are not selected as astronauts may be placed in other positions within NASA depending upon Agency requirements and manpower constraints at that time. Successful military candidates will be detailed to NASA for a specified tour of duty.

NASA has an affirmative action program goal of having qualified minorities and women among those qualified as astronaut candidates. Therefore, qualified minorities and women are encouraged to apply. Pay and Benefits

Civilians

Salaries for civilian astronaut candidates are based on the Federal Governments General Schedule pay scales for grades GS-11 through GS-14, and are set in accordance with each individuals academic achievements and experience.

Other benefits include vacation and sick leave, a retirement plan, and participation in group health and life insurance plans.

Military

Selected military personnel will be detailed to the Johnson Space Center but will remain in an active duty status for pay, benefits, leave, and other similar military matters.

QUESTION:

Can you explain this sentence I read today in the New York Times: “the geometry of the universe is perfectly flat, where the angles of all triangles always add up to 180 degrees.”

REPLY:

First, in order to say something has a geometry, as we understand it, you need to represent it as a geometrical figure. So, let’s take a 90_ triangle. Draw one if it helps. Note that it is comprised of three angles: one angle equals 90_, and two equal 45_.

Okay, now take the vertical axis of the 90_ triangle and, in your mind, push it down until it is horizontal. Now what do you have? A triangle where each of the angles equals 180_ — a flat line. Now try to imagine doing the same to a three-dimensional triangle — like a pyramid — a squashable pyramid.

QUESTION:

Since skin is generally not preserved in fossils, how do scientists come up with the colors for dinosaurs? 

REPLY:

The following is according to “Dino Russ,” of the Illinois State Geological Survey: “Direct fossil evidence for dinosaur skin color is unknown. Paleontologists think that some dinosaurs likely had protective coloration, such as pale undersides to reduce shadows, irregular color patterns (“camouflage”) to make them less visible in vegetation, and so on. Those dinosaurs that had enough armor, such as the stegosaurs and ceratopsians, may not have needed protective coloration but may have been brightly colored as a warning to predators or as a display for finding a mate. Most dinosaurs probably were as brightly colored as modern lizards, snakes, or birds. So the simple answer for skin color is we do not know. And it is likely we never will because of the chemical composition of pigments and their solubility, and the fact that skin is so rarely preserved, and typically only small pieces as impressions. This means that speculation, based on what we know of pigmentation in living vertebrates, is the main means for our understanding of color and color patterns in dinosaurs. During the first half of the century artists (e.g., Charles Knight, and to a lesser degree, Zdenek Burian and Rudolph Zallinger) often painted dinosaurs in drab green, browns or grays. They based their interpretations on modern analogs such as large mammals (elephants and hippos) and reptiles (alligators, crocodiles, and large varanid lizards such as the Komodo Dragon). These modern analogs normally had subdued colors on their bodies, even if they do have some subdued patterns. Modern artists (Mark Hallett, Greg Paul, William Stout, and many more) have expanded their pallet and given us dinosaurs with brightly colors and patterns that reflect the modern thinking of dinosaurs as energetic, sociable animals. Modern vertebrate analogies display a wide variety of colors and patterns in their integument (skin, scales, feathers, and hair). Based on the few preserved skin impressions we know large dinosaurs were covered in non-bony scales of a variety of sizes that abutted in a mosaic-like pattern. Modern reptiles posses a wide variety of colors and color patterns and there is nothing in theory from precluding dinosaurs from being similarly endowed. Color and color patterns can serve a number of functions in modern reptiles including use in social interactions, thermoregulation, patterns signaling noxious or dangerous quality to predators (aposematism), and defense (cryptic or mimicking coloration or for suddenly revealed bright colors for startling potential predators). It is now felt dinosaurs likely used coloration patterns in these same ways, although which species used what patterns will probably never be known.”

QUESTION:

Hope the New Year was a good one for you. Just wondering if this is real? NASA calls it the EYE OF GOD. This was entirely too cool not to share! Is this a real picture?

REPLY:

And Happy New Year! The image is real. The object’s real name is the Helix Nebula, but in a press release, apparently, NASA did also nickname it “the Eye of God.” It is a planetary nebula — a star like our Sun, which is dying and has blown off a shell of gas. These gaseous shells, when seen through a small telescope, can look green and round, like the gas-giant planet Uranus, which is why they are called planetary nebula, though they really have nothing to do with planets. This particular planetary nebula is the closest to pour Sun and lies at a distance of 450 light years.

QUESTION:

1) How does computer animation work? 2) Do wolves really howl at the moon? and 3) When did the middle finger first become offensive?

REPLY:

1) How does computer animation work? There’s no way to answer this question in a few sentences, it varies from creator to creator. I suggest you rent some DVDs of shows, like Lord of the Rings, or Spiderman, and watch the “bonus material,” which should tell and show you how they created their special animated effects. Many movies today use computer graphics, green screens, and animation in the creative process, and many DVD’s share with you how these effects were created. 2) Do wolves howl at the Moon. No, this is just a myth. But, as with many myths, there is a basis for reality. Wolves, who are active at night, howl as a form of vocal communication. Their howls, however, are great and varied. Some howls are are social — to let their friends and family know where they are, or to keep adversaries away. Some are made to let others know they are celebrating success in a hunt. Others are thought to happen when the wolf is lonely. The fact is, in regions far away from city lights, full moonlight illuminates the landscape brightly, helping wolves to see at night. So during full moonlit nights, wolves are more active, so you are more apt to hear a wolf howling in the night during a full Moon. Thus the relationship. 3) The use of the middle finger as an obscenity may seem modern, but it is not. It dates to 2,500 years ago, and perhaps more. The first written record of it can be traced to Greece, where the comic playwright Aristophanes made a crude joke using the middle finger, which had an aggressive, phallic significance.

QUESTION:

What makes a chicken change colors when it gets older?

REPLY:

I believe, the child is thinking of a young juvenile chick, with its juvenile plumage (down) to keep the bird warm, especially in winter. These are usually earthy colors. When the juvenile plumage molts, the chicken’s “true colors” start to show through. The molt does not happen all at once. So you can see a chick with multiple colors. According to the University of Illinois Extension, the feather patterns and color of a chicken serve as a valuable aid in identifying numerous varieties of fowl. This is used in conjunction with skin and leg color, body shapes, combs, and beaks. The plumage for a fowl is classified as “white” is white in all sections. While the surface of a fowl classified as “black” is a lustrous, greenish black with an undercolor, except where otherwise specified dull black in dark-legged varieties and slate in yellow-legged varieties. Fowl that are “buff” are a medium shade of orange-yellow color with a rich golden cast, but not so intense as to show a reddish cast, nor so pale as to appear lemon or light yellow. Feather colors help to differentiate between males and females in most fowl.

QUESTION:

Please tell me why a rubber duck can float on water and a eraser can’t but both of them are made of rubber.

REPLY:

You’re talking about the principal of displacement. It’s the same reason why a steel boat can float while a stab of steel won’t.

It has to do with the shape of the object and its weight — not what it is made of. The reason the rubber duck floats is because the volume of water displaced by the duck weighs more than the duck, so it floats. The reason the eraser sinks is because the weight of the eraser is greater than the amount of water it displaces. If you could reshape the eraser — make it wider and thinner — it would also float.

QUESTION:

Which gas makes the most of the air around us? How much of the air does it take up?

REPLY:

Nitrogen comprises most of Earth’s atmosphere (78 percent). The next most prominent gas is oxygen (21 percent). The rest are mostly trace amounts of other gases. The Earth’s atmosphere is about as wide as your breath on a marble. From the surface of the earth, it extends upwards to about 300 miles where it simply thins outs until it blends in with space. About 80 percent of the atmosphere lies within about 10 miles of Earth’s surface.

QUESTION:

What can plutonium do if you touched it with your bare hand?

REPLY:

Plutonium is much more radioactive than uranium, which can be held in a hand. Plutonium can be held safely, as long as it does not make direct contact with the skin. So it’s necessary to wear gloves. When the damaging ‘alpha particles’ flee the plutonium nuclei, they penetrate less than one tenth of a millimeter deep in the skin tissues. Here many cells will be killed.

QUESTION:

My son is doing a science fair project on whether or not a colored candle burns faster than a white candle. So far all we can come up with is that all candles are white around the wick and it is the wick that determines the rate of burn. Is this true or does the color of the wax play a part in the burn rate?

REPLY:

A candle’s “burn rate” is how much wax (in weight) a candle burns each hour. Here’s how you determine that: First, weigh the candle you are going to burn. Next, light the candle and let it burn for an hour. Blow the candle out, then weigh it again. The difference in weight gives you the burn rate per hour. If you divide that number into the weight of the candle before it was burned and you can determine how many hours the candle will burn. Of course, you have to control the conditions surrounding the candle. Drafts, and other exterior sources can affect a candle’s burn rate.

As for the color of the candle? Try it out for yourself. But I believe you’ll find that color (a simple dye) does not affect the candle’s burn rate. The fact is, the candle’s wick can only absorb so much wax at a time, so it feeds the same amount of fuel into the candle’s flame.

QUESTION:

What’s the heaviest gas?

REPLY:

The heaviest known gas is radon, the 86th element in the periodic table. Radon is one of the "noble" gases, meaning that it will not bond to other atoms — so it’s one of the "elite class" of gases. At room temperature and normal atmospheric pressure, Radon weighs 222 grams, which is about half a pound.

QUESTION:

Can you please tell me what was the Tollund Man is?

REPLY:

Tollund man is a "bog man" — a body found in a peat bog. In this case, the body was found by two brothers in 1950 in a peat bog in the Tollund peat bog, which is about 6 miles west of Silkeborg, Denmark. The body looked so fresh that they thought they had uncovered a recent murder victim. But a scientific study of the corpse (especially radiocarbon dating of his hair) revealed that "Tollund man" lived about 2,400 years ago! The peat preserved his body so well that even some of his clothes was preserved, including a pointed skin cap on his head and a smooth hide belt around his waist. As for his features, Tollund man was about 20 years old, had very short hair and was clean-shaven, except for some 5:00 shadow.

The poor lad appears to have been murdered, though. A rope was drawn tight around his neck. An examination of the man’s stomach revealed that his last meal had been a kind of vegetable soup. He had not eaten for a day before his death. The body is currently kept in the Silkeborg Museum in Denmark.

QUESTION:

I was wondering if there are any metals that have colors such as: Green; red; orange; purple; yellow; blue. (and these colors before they are painted)?

REPLY:

Nice question. The answer is yes!.

Here’s a list of naturally colored mineral gemstones:

Green: Emerald (Intense green or bluish green)

Red: Red Beryl (Raspberry red)

Orange: Rubicelle (Orange)

Purple: Amethyst (Purple)

Yellow: Topaz (Yellow)

Blue: Sapphire (Blue)

And these are just some common ones. Mineral gemstones come in all manner of colors.

QUESTION:

Where do you find magnesium?

REPLY:

According to the Unites States Geological Survey, magnesium is the eighth most abundant element and constitutes about 2% of the Earth’s crust, and it is the third most plentiful element dissolved in seawater. Magnesium is found in over 60 minerals. Magnesium and other magnesium compounds are also produced from seawater, well and lake brines and bitterns.á Magnesium metal’s principal use is as an alloying addition to aluminum, and these aluminum-magnesium alloys are used mainly for beverage cans. Magnesium alloys also are used as structural components of automobiles and machinery. Magnesium also is used to remove sulfur from iron and steel.

QUESTION:

Is there a name for the unoccupied focus of an elliptical orbit? We’re having a debate and can’t find anything about it. We’ve been through La Grange points and barycenters already

REPLY:

A great ask the scientist question!

In equations, the foci (plural for focus) are written in equations simply as F1 and F2 — or F1 and F2.

I don’t know of any other names for these fixed points, but I suppose you could name them what you want. 🙂

Perhaps someone is confusing foci with apses, which are the periapse and apoapse points in the ellipse — or the points along the ellipse where the point is closet (periapse) or farthest away (apoapse) from a central point. In astronomy we call these positions perihelion and aphelion, when we talk about the position of a planet or minor body orbiting the Sun.

QUESTION:

What would happen if liquid nitrogen and fresh lava mixed together?

REPLY:

Another great question. Of course, liquid nitrogen can be used to freeze objects. Here on Earth, nitrogen is in a gaseous state. To make liquid nitrogen we have to use machinery to lower the ambient temperature to a point below -320 degrees F — the boiling point of nitrogen. Put a rose into liquid nitrogen and hit it with a hammer and it will shatter like glass. And, so, yes, if you place lava into liquid nitrogen, it will freeze.

Actually, believe it or not, scientists have experimented with the cooling rates of lava placed in liquid nitrogen. The so-called “quench rate” for lava in liquid nitrogen is 18°C per second. But these experiments were preliminary, and there’s still a lot to learn about how the heat from lava transfers in liquid nitrogen and also air.

If you’re thinking that scientists can use liquid nitrogen to stop an advancing lava flow, that’s an interesting thought. But it’s not practical. Again, the problem is we need we need machinery to coax nitrogen out of its gas state. So it’s an expensive ordeal to create just a little liquid nitrogen. Lava, on the other hand, has a seemingly endless reserve. Scientists have had better luck with slowing an advancing lava flow with sea water. Still, lots of water has to be available. According to volcanologist John Dvorak, a typical eruption of the Hawaiian volcano Kilauea, for example, erupts enough lava to fill a large sports stadium, such as Candlestick Park in San Francisco. To cool that much lava you would need to spray as much water as could be held in Candlestick Park.

Now for a bit of trivia: Did you know that ice volcanoes on Neptune’s moon, Triton, may erupt liquid nitrogen like lava?

QUESTION:

While working out at CURVES this morning a question came up as to why colored soap only produces white bubbles and suds. Some concluded that it’s because suds and bubbles are so fine that you can’t see the color? I personally don’t think that’s the answer so please let us know.

REPLY:

Soap making involves a chemical reaction between the ingredients, such as oil, lye, and water. Color is an additive, which reacts with certain fats and oils. Holly Deyo, a soap-maker, says that the color of a bar of soap depends on the ingredients used to make the soap:

"The mixture will have tendencies toward a certain color. For example, soaps containing cinnamon, clove, vanilla or nutmeg will have brown tones. Cornmeal will give soap a pale yellow color while kiwi and rosemary will yield green tones. Paprika will turn soap peach. Fats and oils will contribute their own characteristics too. Adding herbs, rose petals, bran or oatmeal will give the soap its own unique colorings as well as textures."

The fact that colored soap gives white bubbles is not a mystery but an intent. It has to do with the amount of color that is added to the soap when it is being made. Altering the ratio of certain fats can change the soap’s color. How long your color is in the soap before pouring into the mold will also affect the color. Most soap makers do not want to overdo the color, because too much color will, in fact, give you colored bubbles, which can stain! So, the art is to add just a little bit of color, which all but vanishes when the soap froths up. "Unfortunately," says Deyo, "coloring will be a lot of trial and error, but it won’t affect the usage of soap unless you end up with colored bubbles which should be discarded."

For more information about soap and its bubbles, you can email Deyo at [email protected]

QUESTION:

I’m a teacher and freelance writer. According to a recent Discovery Channel program on the Colorado River, a large, warm inland sea once covered much of what is now the United States. Was this before or after the Ice Age glaciers that carved out the Great Lakes? Can you help me find the answer to this question?

REPLY:

It’s a very interesting question. Kind of chicken and egg.

But first: The great shallow inland sea that covered the Western United States happened during the Cretaceous period. This seaway existed from about 98 million years before the present until about 65 myb.

The Great Lakes region, however, has roots that extend back to 185-520 million years ago, when the area was covered with a shallow saltwater sea. When the seas, in turn, disappeared, they left extremely soft seabed — porous rock made up of sand and fossilized sea life. During most of the last million years, however, the climate in the region favored the formation of glaciers. When a retreating glacier — about 12,000 years ago — reached this soft seabed substance (as it melted its way north), the glacier was able to dig much, much deeper than when it dug into hard, non-porous rock. So the glaciers dug the Great Lakes in their present location. Later glacial puddles, some 1,000 feet deep, filled with water and became lakes. For instance, A river of ice half-a-mile thick and 22,000 square miles in surface area carved the hole we now call Lake Michigan.

QUESTION:

Does an octopus migrate or hibernate?

REPLY:

Great question. Extensive studies in Japan, show that octopus migrate seasonally, though they do not travel far. The researchers found that an octopus will live in the shallows (in about 150 feet of water) during the summer but migrate to deeper waters (about 300 feet) come winter. It’s called inshore-offshore migration. But here’s what’s interesting, it appears that only the males migrate! After they mate in the shallows in autumn, the males will migrate to deep water and die! The females stay in the shallows for 6-7 months with their eggs. The females do not eat during this time and remain with the eggs until they hatch — after which time the females die!

Wow, sounds like such a tragedy. Anyway, I guess you could argue that the females, then hibernate for 6-7 months with their eggs, because they lives in cracks and holes in the rocks.

QUESTION:

Why does dirty snow melt faster than clean snow??

REPLY:

The short answer is that dirty snow absorbs more heat than it reflects; its just the other way around with white snow. Think of it this way: Why do many people wear white clothing in the tropics? Because it’s "cooler" than wearing black clothing. It’s also why you’ll find more white cars in the tropics — black cars absorb heat.

QUESTION:

How many pizzas fit across the diameter of the sun? Mercury? Venus? Earth? Mars? Jupiter? Saturn? Uranus? Neptune? Pluto?

REPLY:

What a great question. Actually the problem is quite simple to solve. A typical pizza is 12 inches in diameter or 1 foot.

Now, there are 5,280 feet in a mile. And the Sun is 850,000 miles in diameter, so all you have to do is multiply 5,286 by 850,000 and you have the number of pizzas that will stretch across the width of the Sun. And that answer is 4,488,000,000 (that’s about 4 1/2 billion pizzas!).

You can do the rest. Here are the diameter of the planets in miles:
Mercury = 3,038 miles
Venus = 7,520 miles
Earth = 7,926 miles
Mars = 4,217 miles
Jupiter = 88,846 miles
Saturn (without rings) = 74,898 miles
Uranus = 31,736 miles
Neptune = 30,775 miles
Pluto = 1,419 miles

QUESTION:

What is the formula for determining the amount of carbon dioxide in a can of Coca-Cola?

REPLY:

First, did you know there are different amounts of carbon dioxide in different cans of different soft drinks?

Here’s how you can find out:

Take three different brands of soft drinks in a can (one of which is Coca-Cola). Now, place each can (one at a time) on a balance scale and measure and record the weight.

Next, open each can and repeat the procedure. You’ll find that the weight of each can is less by a tiny amount (which is the amount of carbon dioxide that was in the drink before it was released). To find the amount of carbon dioxide in each soft drink then requires you to simply subtract the weight of the open can from that of the unopened can.

QUESTION:

How do the microchips work? Are they like a brain? And what are the differences between vacuum tubes and chips?

REPLY:

Believe it or not, though we are used to having very compact computers today, the earliest computers were enormous machines. It literally required a house to house one! These machines used as many as 20,000 vacuum tubes — each the size of a glass soda bottle. These tubes were not so much the brains but the *life* of the system, though, yes, they were indeed the predecessors to today’s microchip. The tubes controlled the flow of electrons in a vacuum and acted as a type of switch. Now get this: The last computer to use vacuum tubes occupied 1,500 square feet and weighed 30 tons! The problem with the tubes is that they glowed red hot and burned out very fast (about. one every 7 minutes).

Well all this ended by the 1950s when transistors came into the picture. A transistor is essentially a tiny electrically operated switch that can alternate between "on" and "off" many millions of times per second. But even these chips were large and cumbersome.

Today transistors are part of an entire electronic circuit on a tiny piece of silicon, that is called a chip. As technology improves, we are able to make these chips smaller and smaller. A microchip is a tiny piece of silicon that contains millions of microminiature electronic circuit components, mainly transistors.

Imagine this: an 8-inch silicon wafer could have a grid of nearly 300 chips, each with as many as 5.5 million transistors!

QUESTION:

Is it faster to fly in a straight line from New York to England or in an arc?

REPLY:

It is shorter to fly that route in an arc. The Earth is not circular but an oblate spheroid — wider at the equator than at the poles. For instance, at the equator, the Earth rotates at 1,000 miles per hour; at a latitude of 50 degrees it rotates at a speed of 640 mph. At at the latitude of Greenland it rotates at about 300 mph. Lines of longitude are divided up into time (minutes of *arc*). By flying north then arcing east you (rather than in a straight line) you save on time because the lines of longitude are converging.

Think of it this way. What would be faster to do, travel around the Earth at the equator (latitude 0 degrees all the way) or around the Earth just 1 degree from the pole (latitude 89 degrees)? Just look at a globe!

QUESTION:

Who invented the Australian clothesline, and can you send some info to me?

REPLY:

The Australian clothesline (a rotary clothesline with a hoist) was created in 1946 by Lance Hill to accommodate the outdoor needs for those living in cramped housing areas; it is called a Hills Hoist and it is a typical clothesline found in the vast majority of Australian backyards. It was also featured in the Sydney 2000 Olympics Closing Ceremony.

Today Hill’s genius is carried on by his company, Hills Industries — which, according to its web site is "a diversified manufacturer of lots of clever Australian products and services. Hills currently operate businesses in three industry segments; Home and Hardware Products, Electronics and Building and Industrial Products."

QUESTION:

How did the scientist find kelvin and what did they do?

ANSWER:

Did you mean the Kelvin temperature scale?

If so, it is named after the British mathematician and physicist William Thomson Kelvin, who proposed it in 1848. The Kelvin temperature scale employs an "absolute bottom number" called "absolute zero" which means no temperature can exist below it. Absolute zero, or 0° K, corresponds to a temperature of -273.15° on the Celsius temperature scale. By the way, unlike when writing temperatures in the Kelvin scale, it is the convention to omit the degree symbol and merely use the letter K.

QUESTION:

Why does the sun rise in the east and set in the west?

ANSWER:

Thanks for writing. Actually, this answer is quite simple and fun to imagine. The Sun rises in the east and sets in the west because the Earth turns on its axis in the opposite direction — from west to east. So, the next time you see a sunset, think of this: the Sun is not setting, the horizon is moving up and across the Sun! In other words, you’re the one who’s moving — not the Sun.

QUESTION:

What percent of the sun’s rays hits Earth?

ANSWER:

Good question. Overall, about 43 percent of the radiation reaching our planet from the Sun hits the Earth’s surface; 42 percent is reflected back into space; and 15 percent is absorbed by the atmosphere.

But think about the weather on any given day on Earth. The amount of sunlight that reaches the Earth’s surface each day depends on the amount of cloud cover and some other atmospheric factors. Typically, we can say that for average weather there is 52 percent cloudiness.

Clouds will reflect back into space 75 percent of the sunlight striking them. That means, on an overcast day, only 25 percent of the Sun’s energy reaches the ground.

Now, energy that reaches the ground is affected in different ways. Snow cover will reflect 75 percent of the sunlight striking it and absorb only 25 percent. Dark forests absorb about 95 percent of solar energy. So, you see, there are a lot of variables involved.

QUESTION:

My daughter is only 6 years old. She asked me a couple of science questions. It is hard to explain the answers to her without getting into some difficult scientific terms. Can you help me explain the answers to her in a simple enough way so a 6 year-old can understand?

1) Why don’t birds get burned when they stand on a wire?

2) How come flamingoes’ legs are so strong? They can sleep with just one leg standing.

3) Are hawks born with strong wings? How come their wings are so strong? They can fly without flipping their wings for a long time.

REPLY:

First, many wires are insulated. So there is no problem when a bird lands on an insulated wire — just as nothing will happen to you if you hold the cord of an electric toaster and plug it in. But birds CAN land on uninsulated wires and survive. Why?

The simplest way to answer this question (without getting into Van de Graff generators) is to say that when a bird stands on the wire, it does fill up with electrons (just as you do when you shuffle across a rug on a cold morning. But you can shuffle across the rug infinitely without feeling a thing. . . but touch a door handle and ZAP! A static discharge occurs. What happens is that all those electrons you’ve stored suddenly *flow* (a current), and it’s the current that can cause pain!

Anyway, a simpler way to explain the problem is to say that, like water, electricity follows the path of least resistance (which is why water doesn’t flow up hill.) So what’s easier for the current to do — to move along a straight wire, then, when it encounters the bird, change course, go up one leg of the bird, slice through the body of the bird, change course again, move down the other leg until it reaches the foot, leave the foot, then continue its course along the wire?

No, the flow (current) of electrons in the wire essentially ignores the bird and continues straight through the wire. But let that bird remove *one* foot from the wire and touch, say a piece of metal on a pole and . . . well . . . you know the rest of the story.

2) How come flamingoes’ legs are so strong? They can sleep with just one leg standing.

First, flamingos are not the only birds that sleep on one leg, other birds do too — including some canaries! It’s just that the flamingo, because of its size and pink color, draws attention to it.

Although big, flamingos do not weight much. Ever hold a feather? Think of the bird then as a big bag of feathers. Still standing on one leg does get tiresome, so the birds will occasionally switch legs. But the real key is that the bird has a locking mechanism above its foot, which keeps the leg from collapsing as the bird sleeps.

Now, why do they stand on one leg? According to the National Wildlife Federation, a flamingo’s leg is long, featherless and coursing with blood vessels — a perfect radiator. To stay flight-ready, however, the birds must keep warm around the clock; on cool nights, they can’t afford to leave two radiators on. Long-legged birds aren’t alone in this habit.

And 3) Are hawks born with strong wings? How come their wings are so strong? They can fly without flipping their wings for a long time.

Well, Now here’s a difficult one to answer simply, except for the first part of the question. Are hawks born with strong wings? No, when hawks are born, they have no feathers! But they are covered with down (to keep them warm). After five or six weeks, flight feathers grow in; they then start to take short flights; they stay with their parents until they learn how to fly well. It’s like walking. Do children know how to walk when they are first born? No. They have to be taught, and they eventually gain strength.

The reason it can ride an updraft for a long time is the size and shape of its wings. A red-tail hawk, for instance, has a wing span of more than four feet from tip to tip. The wings are long and broad and slightly cupped, so they are extremely efficient at catching the wind and lifting the hawk with minimal effort. The wing bones themselves are hollow, which reduces the weight of the bird and also makes it easier to hold the wings horizontally for long periods of time. An adult hawk, though large, weighs only about a pound or two.

QUESTION:

I was wondering if frogs can see color. I’ve looked in books and on line but I can’t find anything. Am I not looking hard enough, or is it just not there?

REPLY:

Many sources say that frogs cannot see color — that they perceive the world in only black or white. But recent scientific studies have revealed that frogs can indeed see color. Color perception is a very complex science, but, in short, color perception we’re concerned with occurs in the eye’s "cone" cells.

The number of shades of colors an animal can see (given that the animal’s eyes have cone cells; not all do) depends on how sensitive these cone cells are to different wavelengths of light. The shorter the wavelength of light, the bluer the object; the longer the wavelength, the redder the object. The cone cells in an average human eye can differentiate between about 150 shades of color.

I do not know offhand how many shades of color a frog can see but in 1986, researchers discovered that frog eyes have abundant cone cells; so frogs presumably can see color. A more recent study in 2001 (on animal predation) confirmed that frogs can detect differences in shades of color.

QUESTION:

Who discovered potassium?

REPLY:

The short answer is Sir Humphrey Davy (1778-1829) who was a self-educated British chemist. He discovered both potassium and sodium in 1807. For more information on him, go to this Web site.

QUESTION:

Who was the first female pharaoh?

REPLY:

I bet most people would think it’s Cleopatra. But she’s not. The first great woman Pharaoh was Hatshepsut — one of the most successful female rulers of Egypt. Some sources claim she was the first female pharaoh, but other sources tend to accept that there were others before her. but none certainly were as great.

Hatshepsut was the fifth ruler of the 18th-dynasty (1473-1458 B.C.) and her reign lasted for about 20 years, before disappearing from history. Still, that’s the longest reign of all the female Pharaohs. During her rule, she expanded trading relations and built magnificent temples as well as restoring many others. And though she is often portrayed as a peaceful ruler, she did have some military conquests.

Hatshepsut was indeed interesting. She dressed in men’s clothing, and, with the backing of the temple of Amen, proclaimed that she was the divine daughter of the god Amen. Hatshepsut gave up her rule once her nephew grew into a man. What happened to her after that is a mystery.

Her funerary temple still stands, and it is filled with many beautiful scenes that prove herself as Pharaoh.

QUESTION:

How long did it take to build Apollo 13?

REPLY:

The Apollo 13 rocket is a type of rocket called a Saturn V. It is the same rocket used in all the Apollo missions. It was the biggest and most powerful rocket ever built. The overall layout of the Saturn V is simple. The Saturn V is basically a stack of large welded fuel tanks with three stages and rocket engines. Inside, the rocket contained three million parts in a maze of fuel lines, pumps, gauges, sensors, circuits, and switches — each of which had to function reliably, and did.

But, The Saturn V rocket was not simply made. It is the end result of a long history of rocket design. In fact, the Apollo program did not start with the Saturn V — but with the Saturn C-5 design of 1961. And before that, researchers were working on creating a guidance system for the Saturn rocket as early as 1958.

Different corporations worked on the three different stages. The first two stages took the longest to test and create — namely, about 4 years. Once all the bugs were out of the system, the rockets could be manufactured, assembled, and ready for flight within a year.

To see a breakdown of the entire process for Apollo 13 go to this Web site.

The first Saturn V to fly was SA-501, carrying the Apollo 4 spacecraft into orbit on November 9, 1967. Manned Saturn V launches began with Apollo 8 in 1968 and continued through Apollo 17 in 1972.

Today, rebuilding the Saturn V would cost about 6-10 billion dollars, and funded over a period of several years would only be a fraction of NASA’s yearly budget of 14.4 billion dollars. Rebuilding the Saturn V today should be much easier than it was in the 1960s because the technology in this field is better, and the manufacturing techniques have been vastly improved (in fact, many manufacturing techniques used today are here because of the Apollo program).

Here’s another bit of trivia. It took two and a half years to build each Lunar Module — the spidery-looking ship that transported the astronauts from their orbiting space capsule to the Moon and back.

QUESTION:

I was just wondering if you could help me out with a science question. Why is it that in the country, all of the trees that you see in the woods are very tall and the branches don’t spread out as much, and the trees in the city are shorter and more spread out? Thanks!

REPLY:

Thanks for the great question. Of course, there are many different varieties of trees, but, no matter, the answer you are looking for, I believe, has to do with "space." In a crowded forest, trees are packed in relatively tightly. Any new tree that grows, has to find a way to "fit in" in these tight spaces, so they grow upward more than outward. They do this also because the greatest amount of available sunlight is above them; the trees surrounding them tend to block out a lot of the nourishing sunlight that comes in from the sides. So the trees tend to grow more up than out.

In a city, trees can be separated by great distances, so they have little competition for nourishment and space. This allows them to spread out in all directions.

Imagine steeping into a bus fully packed with people, and you want to stretch your arms. How would you do so? Most likely, you would not want to bother others around you, so you would pull you arms up along your body and stretch them upward.

Now imagine you are the only one on the bus. How would you stretch? Yes, you would stretch any way you want.

QUESTION:

I light 2 wax candles every Friday night and they usually last for (at maximum) 6 hours. This week they both lasted for nearly 22 hours — can this be scientifically explained, or is it of the paranormal?

REPLY:

Nothing paranormal going on here. I do not have enough information to say anything specific, but I can be general. I have to assume, for example, that you are using the same type of candle each night. I have to assume this because you can increase the burning time by increasing the diameter and length of the candle.

A candle that measures 2 centimeters (0.8 inches) in diameter will burn 20 minutes for each centimeter of candle length. So, if the candle is 3 centimeters (1.2 inches) tall, the candle will burn for an hour. A candle 10 centimeters (4 inches) in diameter will burn 305 minutes for each centimeter of candle length.

The above data is only approximate. The real burning duration depends on the room temperature and the draft situations.

The paranormal doesn’t figure into the equation.

QUESTION:

How far away from Earth is Saturn?

REPLY:

Roughly speaking, Saturn is, on average, 800 million miles from Earth. If you don’t need to be precise, you can throw out a "billion" miles . . . as the late Carl Sagan loved to say.

QUESTION:

We are breeding parrots and were wondering if metal halide lights are bad for their eyes or if they would react in any way to the use of them in the aviary?

REPLY:

Hmm, this question is a bit out of bounds; you really need to speak to a vet. But here’s what I’ve learned about parrots in captivity:

Don’t forget full spectrum lighting! Parrots need full spectrum light in order to properly absorb nutrients such as calcium. You can provide full spectrum light by either allowing your bird access to unfiltered sunlight (meaning not filtered through glass) or by purchasing a full spectrum lighting system. These can be expensive. The bulbs themselves can run $30-$40 and only last for about 6 months if used for approximately 4 hours daily.

That’s an opinion of one. To learn more you can go to this Web site.

Now, you will want to inquire about the amount of lighting a parrot needs; I may be mistaken, but parrots may not prefer a lot of light.

Metal halide lights come in a variety of spectral outputs. A 5500 Kelvin is a full spectrum bulb, which means it contains all aspects of the light spectrum, just like the Sun. But you certainly need to do some reading about how much light is appropriate and how long a parrot should be exposed to the lights for sleep and health concerns.

The site I referred you to includes a link to an avian vet.

QUESTION:

What does velocity mean?

REPLY:

Perhaps you’re wondering if there is a difference between velocity and speed, which some works use interchangeably. But in physics, speed and velocity have distinct differences. Speed is a scalar quantity, while velocity is a vector quantity. Now what does that mean?

We measure a scalar quantity by "magnitude" alone. For instance, we can say that something (a car, person, dog, etc.) is either fast or slow moving. So its speed is either fast or slow. If there is no movement, there is zero speed.

But velocity is different. Velocity is a vector quantity, meaning that it is described by magnitude and direction. It refers to "the rate at which an object changes its position." The formula is Final Velocity = Acceleration x Time.

Imagine a car that starts from rest and undergoes an acceleration of 3 miles per hour per second for 10 seconds, heading east. Well at the end of 10 seconds, the final velocity will be 30 miles per hour, east.

Notice I’ve used the words "Final Velocity." That’s because the car, which was at rest, had to gradually build up its acceleration to reach 3 miles per hour per second. So the car’s Average Velocity over the 10 seconds is about 15 seconds. As a general rule, "Average Velocity" is 1/2 the Final Velocity.

Note too, that in describing the velocity of the car I included its direction. You need that information to fully describe the velocity of the object.

The best way to sum it up is that velocity is speed with a direction.

QUESTION:

Do you know where I can find the ultimate IQ test that is free?

REPLY:

You might try checking out the Mensa Web site at www.mensa.org.

Personally, however, I doubt that any test can accurately portray one’s "intelligence." I leave that for you to figure out; maybe that’s the true intelligence quiz.

QUESTION:

Can chickens fly? If yes, why do they stay on the farm?

REPLY:

Like turkeys, chickens can fly; they can’t fly as well as turkeys, but they can fly. Chickens spend most of their time on their feet, pecking at the ground. They fly only to flee from danger. That’s why they stay around the farm, because, unless they’re being chased by, say, a cat, they’re happy to stay where they are protected — and where they can be close to their nests and food.

Chickens have powerful muscles that help them to fly. These muscles, a type of skeletal muscle called a fast-twitch muscle, work, and tire out, quickly. They’ve been likened to the muscles you’d find in a well-trained sprinter’s legs. These muscles work hard and fast, but only for short distances. (If you want to run a marathon, you don’t want to develop fast-twitch muscles in your legs.)

Fast-twitch muscles do not have as many blood vessels as slow-twitch muscles, like those found in a bird’s legs and thighs. Blood vessels supply muscles with food and oxygen. So it makes sense that the legs and thighs need more blood vessels because chickens are always on their feet and don’t need to move around quickly. In fact, that’s why the meat in a leg or thigh of a chicken or turkey you eat is dark — it has more blood vessels. And that’s why the chicken breast you eat is "white meat" — it has fewer blood vessels.

By the way, did you know that there are prairie chickens that are much better fliers than farm chickens? The Illinois prairie chicken (tympanuchus cupido), for instance, can fly up to 50 miles per hour, like a duck. So, when is a chicken like a duck? When it’s a prairie chicken!

QUESTION:

If a nuclear bomb would happen to detonate near the following elements, which would be more harmful or cause more potential danger due to the chemical elements:

(a) 1000 tons of water
(b) 1000 tons of gold
(c) 1000 tons of mercury

My father and are in disagreement about this. I say it is the gold since he atomic weight is heavier and the heavier elements could possibly cause other harmful reactions from the radiation of energy.

REPLY:

First, since a nuclear bomb is detonated in the air; the damage is caused by the spread of radiation and the resulting shock wave.

Here are some facts: at very high temperatures, such as those experienced in a nuclear blast, atoms don’t exist — only separated nuclei and electrons; and these particles are moving very fast, just as they do in the interior of stars. The particles produced in radioactivity are in some cases fast-moving nuclei. These nuclei can interact with existing atomic structures and change elements.

A change of one element into another used to be called "transmutation of the elements." Although elements are immutable in chemical reactions, in nuclear reactions elements do change. For instance, lead has been changed into gold. Likewise, the other elements beyond uranium are created by neutron absorption . . . leading to nuclei with more protons and a higher atomic number. These are all radioactive.

So, if I understand you question correctly, I suppose the answer to your question is that the worst nuclear reaction would be the one that changes one radioactive element into one that is more radioactive.

QUESTION:

I’m doing a project on how icicles are formed. I need to know the history, if any. Could you please send this to me A.S.A.P.?

REPLY:

Let’s look at how icicles form on a house. The cycle starts when warm air in the attic causes snow on the roof to melt. As the melt flows down the roof, it encounters the cold surface of the roof over the eaves. The melt will freeze if the surface of the roof over the eaves is below 32°F. This is the foundation of an icicle, which begins as water drips off the freezing roof edge or gutter. Icicles grow lengthwise by freezing at the tip of a thin tube of ice that’s filled with water. At the same time the icicle widens as thin films of water flow over the outer surface and freeze. Icicles grow in length at rates of 8 to 32 times that of the diameter — depending on the rate of flowing water and air temperature.

Interestingly, the rate of growth in length decreases with increased water supply, but the rate of growth in diameter stays about the same — since the thickness of the flowing film of water over the icicle surface varies little. Decreased temperature and increased wind both lead to increases in diameter and length growth rates of icicles. An icicle becomes solid when the central liquid core freezes.

QUESTION:

Why do some objects absorb colors, and others don’t?

REPLY:

Very interesting question. Here’s the scoop. Although electrons on the outside of an atom or molecule are responsible for absorbing, and emitting light, the colors we see are more dependent on the absorption and reflection of light by an object’s surface structure on the molecular level (a very complicated subject indeed)! So that’s really the answer to your question — in brief. A leaf looks green because it absorbs most of the red and orange part of the spectrum (the rainbow of colors that makes up white light) and reflects in the yellow to blue parts. A rose looks red because it does the opposite, absorbs the blue and green and reflects the red and orange. But the degree to which, say, a rose looks red or a shade lighter, depends on the amount of light being absorbed or reflected on the molecular level — and that amount is dictated by the object’s surface structure on the molecular level.

QUESTION:

Is anyone working on a method or device to allow heat to escape from the atmosphere in case greenhouse gases build up to obvious life-threatening levels?

Is anyone working on creating a scrubber of some sort to replace the effects of the world’s rainforests after they are destroyed to dangerous levels?

Thank you for your answers and advice on how to research these topics more thoroughly in advance,

REPLY:

Here is the response from two of my friends, Aimé and Judith, who are working in global climate change and happen to be visiting me at the moment:

"These are both interesting questions. No one is working on the technologies you ask about, because the processes involve huge quantities of material and energy on huge scales of space and time. The ‘greenhouse effect’ is due to the presence of ‘greeenhouse gases’ in vast quantities, which took thousands of years to accumulate. Gases like CO2 that humans contribute to, are less important than water vapor, yet still very important. Another difficulty is that changes made today will take decades to have an effect."

"Similarly, the role of the rainforests as ‘the lungs of the planet’ is too large to be fulfilled by anything like the technologies we can even conceive of today. It would be like the movie ‘Total Recall’ — real science fiction."

"Regarding your first question, a related topic is the attempt to remove CO2 from the atmosphere, e.g. by growing forests or increasing other biomass. The technical term for this is ‘carbon sequestion’ or ‘carbon sequestering.’"

"If you want to do some more research on these topics, the following websites might be a starting point:

Intergovernmental Panel on Climate Change
University Corporation for Atmospheric Research

Have fun!
Aimé and Judith"

QUESTION:

Ra

What does Ra look like?

REPLY:

Re (Ra), the Egyptian god of the Sun and the creator of everything, can take on many forms, including a scarab beetle, a lion, a hawk, and a cat. But most often, you see Re portrayed as the midday Sun — when Re is in "human" form, looking like a man with a hawk’s head. In his right hand, Re clutches an ankh (a symbol of life) and in his left hand he holds upright a scepter (a symbol of power). Atop Re’s head you’ll also see a large disk (representing the Sun) encircled by a cobra. Ancient Egyptians believed that the Sun was either Re’s body or his eye.

Re travels across the sky in this bodily manifestation in a boat, which looks like a canoe with upturned ends. Actually Re used two boats — one in the morning, and one in the afternoon. The morning boat, Matet, means "becoming stronger." After noon, Re takes the afternoon boat, Semktet, which means "growing weak."

QUESTION:

Is there such a thing as a noise bouncer? We have barking dogs all over the neighborhood and find it hard to get a good night’s rest. Speaking to the owners doesn’t appear to help! There are also no bylaws concerning barking dogs, so there is nothing the local law enforcement can do. If such a thing (as a sound bouncer) existed, it would be the perfect solution! Any suggestions would be appreciated.

REPLY:

Good question. You’re not alone. Many people are affected not only by barking dogs but also the use of power tools, lawn mowers, air conditioners, swimming pool pumps,and public facilities that contribute to noise pollution. Extreme disturbances in some neighborhoods have led city councils to respond by drafting an Environmental Noise Policy. But that’s extreme. The simplest solution is to create or install a "noise barrier" or "sound wall." The San Francisco Chronicle, for instance, publishes a gardening column. The columnist, Michele Driscoll Alioto, suggests that if readers are bothered by neighborhood noises when they are seeking peace and quiet in their gardens, they can help solve the problem by using plants and soil as a noise barrier. The columnist states that soil is an extremely effective sound barrier, and an earthen berm would therefore work very well. She then suggests planting a hedge of evergreen plants or a line of trees on the berm to further reduce the noise.

Such an environmental friendly way of addressing the problem may be a better alternative to, say, building a "whisper wall" made, usually, of concrete.

One person who was affected by barking dogs on both sides of his house has been building a different kind of noise barrier. On the dog’s side of the fence is corrugated steel that should adequately reflect and scatter the barking. On the inside will be a rough-sawn plank wall so he does not have to look at corrugated steel whenever he goes outside, and sandwiched inside is R-11 fiberglass covered with 15# tar paper. Due to the lay of the land, the fence must be 8′ high and 48′ long. It’s costing him about $200, and a lot of time.

I’d look into the gardening solutions first.

QUESTION:

Hey! We have to write an essay in science of what good characteristics of a scientist are. What would you say they are?

REPLY:

Funny you should ask. If I want to see a good scientist, I just look in the mirror 🙂 . . . Just kidding.

Seriously, the answer will differ from one scientist to the next, but perhaps only slightly. I believe all scientists share common characteristics but to varying degrees.

If you want to see a good portrayal of a scientist, see if you can find the first episode of the old science fiction thriller, The Outer Limits. It is called "The Galaxy Being" and is about a "lone wolf" scientist/inventor, Allan Maxwell, who makes radio contact with a being from the Andromeda Galaxy. Turns out the Galaxy Being is, like Maxwell, an amateur scientist curious about life beyond its own world. The point here is that two completely different life forms (one carbon based, one nitrogen based) from different galaxies, share two of the most important characteristics of all the scientists — curiosity and wonder.

At the end of the show, the Galaxy Being is mistakenly transported to Earth where the army, of course, tries to destroy it. Anyway, before the Galaxy Being self-destructs, it leaves humankind with a powerful message. "to explore . . . reach out . . . give thought to the mysteries of the universe."

And that, in a nutshell, is what all good scientists do. They explore the wonders of the universe. They are thinkers, tinkers, ponderers, and problem solvers (or at least they try to be).

Which brings us to the next most important characteristic. Some may disagree, but I believe a good scientist has to have an open mind, but not so open that his or her brain falls out. Good scientists will look at a problem from different angles, consider different possibilities when trying to solve a problem. He or she will ask hard questions and listen to the opinion of other scientists about their research (though that does not mean a researcher has to "give in" to those opinions). Certainly, he or she will acknowledge other research, and, if necessary, incorporate that research in his or her own. At the same time, a good scientist is not afraid to stand alone, or go against the grain of traditional thinking or popular opinion — if he or she believes his or her findings are backed by solid research. Think of what Copernicus had to endure! The idea that the Earth was not the center of the universe seemed so ludicrous at one time that the Church considered anyone who believed it a heretic.

What we all seek is "the truth." A good scientist will not fudge data to support his or her own belief. If a scientist has spent years trying to solve a mystery, only to find out that the path he or she has was taking has led him or her to a dead end, then he or she will have to have the courage to say "I have to rethink my approach to this problem," or, "I will try another road." So a good scientist understands there is no right or wrong . . . just the truth.

And though you will not find these last two traits that follow in many scientists, I believe the most beloved scientists are those who are passionate about their work and are willing to share it with the world in a way the general public can understand. That’s why Carl Sagan was so popular; he was a not only a good scientist, he was passionate about science and an excellent communicator.

QUESTION:

Okay, I have a question for you. I was debating with my chemistry teacher, and I need your opinion. Can water flow uphill? I have heard of so-called mystery spots where it appears to, and I have also heard of a river (I don’t know the name) that goes uphill, but I didn’t know if any of this was proven to make it relevant.

REPLY:

Great question. Of course, you must mean can water run uphill . . . because water can be pumped uphill without a problem.

Anyway, the answer, believe it or not, is, yes . . . in the most smarmiest sense, anyway. Imagine, for instance, a roller coaster ride that has a series of sinusoidal ups and downs. Although the overall motion is down, there are twists, turns, and inclines that the car must overcome to reach the bottom. It all depends on the energy of the system.

Although gravity forces all rivers to flow downhill, constrictions in the local topography can force a river uphill – for a while anyway, (thus the "smarmy" part of my response) but that upward flow is just a small part of the actual downward-trending system. So water can flow uphill (for a while) if there’s enough energy in the system.

Here’s another example, though I’ve hardly heard it mentioned in such arguments. What about water in natural springs and wells? The water reservoirs feeding springs and wells can be found beneath the surface opening. Incoming water pressure on these reservoirs force water out through channels in the surrounding rock, which constrict the flow, forcing it upward to the surface.

By the way, the river you may be thinking of is called the "Paria River." Go to the following web site for an intriguing look into the natural history of this oddity:

www.durangobill.com/PariaCanyon.html

Now consider the following experiment by Edgar Boyd (Gillespie School, Chicago, Illinois). To demonstrate another way that water can run "uphill," Edgar uses a Florence Flask, fitted with a stopper with a glass tube running into the flask. The flask has colored water partly filling it. With the flask held inverted on a ring stand, and a container below it, Edgar heats the flask with a flame. The water is expelled as the air inside expands because of the temperature increase. With the heat removed from the flask, the water runs UP the tube, back into the flask, and the gases inside the flask cool down.

QUESTION:

Is it true that snakes cannot climb stairs?

REPLY:

No, snakes can climb stairs.

Snakes are versatile in the way they move. They can choose between four main types of locomotion known as the serpentine glide, the concertina motion, the rectilinear glide, and the side-winding movement. With the exception of the rectilinear glide, favored by boas and pythons, all the other methods of locomotion are achieved solely with back muscles. They cannot do otherwise as they have practically no front muscles.

Of course, the bodies of snakes vary greatly in shape and size. They can be stout or thin, long or short, flat, or round. So you have to take the size of the snake into consideration, the type of snake, and the nature of the stairs. Snakes move about in different ways depending on the surface and situation.

Rectilinear movement is a creeping movement used to climb trees or move in narrow places. In this movement the snake uses muscles to pull its belly scales forward so that the back edge catches on the surface. The muscle then pushes the scale back again, moving the snake forward. Climbing snakes have squared belly scales especially suited to this movement. Concertina movement is used in climbing trees and on smooth surfaces. The snake presses its front end down firmly to anchor itself, then moves its back end forward and presses it firmly down as an anchor. Using this as leverage is moves the front end forward again and on goes the process. There are other unusual ways of moving. One is a jump-like movement some snakes use to avoid danger. To do this they coil up and hurl themselves forward by straightening out quickly, somewhat like a spring. Some other snakes parachute by spreading out their ribs and flattening themselves to catch more air and slow their fall.

Brown tree snakes are commonly encountered climbing on man-made structures. Since they can lift three-fourths of their body using the remaining quarter for support, even small cracks and imperfections in surfaces are enough to give them leverage. Power lines, wooden poles, and guy wires are no greater challenge for these snakes than a tree or exterior wall of a building. In fact, power outages caused by snakes have been a serious problem on Guam since 1978, and the incidence of snake-caused outages continues to cause significant problems. Records show that more than 1,600 snake-caused outages occurred from 1978 – 1997.

QUESTION:

Why salt doesn’t dissolve in the Dead Sea?

REPLY:

Ah, don’t be fooled by the Dead Sea salts. The salts are dissolved. It’s just that the concentration of the salts in the Dead Sea is higher than that in the world’s oceans. Compared to the 3 percent salt content of ordinary sea water, Dead Sea water contains 32 percent salt with relatively high concentrations of minerals such as magnesium, calcium, bromide, and potassium. So the Dead Sea is about 10 times saltier than an ocean.

The Dead Sea’s mineral salts come from the Jordan River and a number of small streams that feed into it. What’s more, the Dead Sea has no outlet. The only way water gets out of the Sea is through evaporation, which in this extremely hot region of the world is fairly rapid. When the water evaporates, it leaves behind all the dissolved minerals in the Sea, just making it saltier. Over millions of years, this process has made the Dead Sea one of the saltiest bodies of water in the world.

QUESTION:

At school we have a trivia question each week. This week’s question is: If born on Neptune, how old would you be on the year 2020?

REPLY:

As you know your age on Earth is in "Earth Years," which is the time required for our planet to make one complete revolution around the Sun: 365 days. Neptune orbits the Sun in 60,148 days (164.79 earth years). That means that if you lived on Neptune 164.79 Earth years would pass before you became 1 year old on Neptune.

But here’s what I want you to do. Go to the following web site and have fun. Be sure to read the section "What’s Going On?" so you fully understand the problem.

www.exploratorium.edu/ronh/age

QUESTION:

Do you know a great website for the names of the inner parts of the International Space Station? I am designing bulletin boards for my 4th-grade classroom. I have done a Destiny Lab window, but need the technical names for the sleeping area, or the food, or the bathroom, or the "doors?" THANK YOU if you can offer any help.

REPLY:

Try these web sites:

www.howstuffworks.com/space-station.htm
http://spaceflight.nasa.gov/gallery/vtour/index.html
http://spaceflight.nasa.gov/gallery/vrml/station

QUESTION:

What is megalithic art? What is the archaic kori? What is mobility art?

REPLY:

Megalithic art is Stone Age art (from 3700-2000 B.C.). A good example are the enormous stonepillars arranged in concentric circles at Stonehenge in England. Some appear as tombs or "passage graves," while others appear to be intricate temples of religious rite and worship.

Khouroi or Kori were ancient Greek statues (of men) that date from the 6th- and 7th-century BC. They are usually standing over a grave, and their appearance and style of artistic impression seems to have been influenced by Egyptian sculptors. To learn more, visit this web site: www.uic.ssu.samara.ru/~ancient/eng/g3s.htm.

QUESTION:

Question 1) What is the parking place for an aircraft called?

Question 2) What animal is tamed to kill snakes?

Question 3) What is the skin of animals known as?

Question 4) Name the bird that has both eyes in front.

Question 5) What was the name of Peter Pan’s fictional land?

Question 6) What is the highest mountain in the world south of Delhi?

Question 7) What everyday kitchen item can be used to remove ball point stains?

REPLY:

Here are the answers to your questions . . . Let me know if I’m the Weakest Link!

1) A hanger

2) A Mongoose

3) Hide

4) Owl

5) Never Never Land

6) Ha, Ha . . . it’s Mount Everest (Latitude 28s 00′) Delhi is 38′ north

7) Well, there are a range of choices. Apparently carpet cleaner, alcohol, and hair spray can be used.

Now I have three questions for you:

1) What is the world’s highest mountain measured from the seafloor?

2) What is the world’s highest mountain measured from the center of the earth?

3) What is the highest mountain in the solar system?

QUESTION:

I have a couple of questions. I hope you can help.

1) Is lava more difficult to accurately date than, say, fossils? Why or why not?

2) Will lava at the beginning of a flow (at the bottom of the hill) be older or younger than lava at the end of the flow (top of the hill). Why?

REPLY:

Great questions.

(1) Is lava more difficult to accurately date than, say, fossils? Why or why not?

First, there are many ways to date fossils, either through stratigraphy, magnetic-field fluctuations, or radioisotope dating of volcanic rocks found near fossils. In radioisotope dating, you must determine the age of the lava found near the fossil in order to estimate the age of the fossil. Radioisotope dating cannot be used directly on fossils since they don’t contain the unstable radioactive isotopes used in the dating process. To determine a fossil’s age, then, you must date older volcanic rock beneath the fossil and younger volcanic rock above; doing so will provide a time-range for the fossil’s age. So dinosaurs, for instance, are dated with respect to volcanic eruptions. Thus, if I have a decent handle on what you’re asking, it’s harder to date the fossil than the lava.

(And, in case you are wondering . . . Carbon14 dating (where you can date, say the charcoal from a burned tree) is useful for dating items up to about 50,000 – 60,000 years ago; but this is too short a half-life to date dinosaur fossils).

(2) Will lava at the beginning of a flow (at the bottom of the hill) be older or younger than lava at the end of the flow (top of the hill). Why?

Well, to answer this question I’m going to have to assume that you mean to start the clock ticking once lava leaves the throat of a volcano, and that the first lava out is older than lava that flows out of the throat, say, an hour later. I’m also assuming this is not a trick question – meaning that if you have a box full of kittens, all age six; if one leaves the box at 1:00 p.m. and another leaves the box at 6:00 p.m. they are still all six years old.

Now, I’m looking at this problem from a different perspective – from the point of view that if a mother gives birth to twins, the first one out is the oldest. Given that clarification, we can now turn to your question.

In the simplest sense, meaning we are looking at a single straight flow of lava, the leading edge of the lava flow will be older than the trailing edge, because it came out of the vent first. But if you are looking at a solidified lava flow and are trying to determine whether the front or back of it is older, well, then, we have a problem to solve.

Picture this: Lava flows out of a volcano’s throat and spreads across the land and cools. Immediately after that flow cools, another comes out of the throat and flows right over the old flow and overtakes it. So the front of this flow is young while the back of the flow is made up of both younger and older rock.

Now imagine that the second (younger) flow reaches the hilltop and starts to pool. Fresher and fresher lava fills the pool until it pours over the hillside. The lava that makes it to the bottom of the hill, then, will be even younger, than, the original young flow that reached the hilltop. The hilltop is a mass of mixed lava, as is the back of the flow.

Now let’s go back to the very first flow. And let’s imagine that it does make it over the hill and plops down at the base of the cliff and cools and solidifies. But it’s followed immediately by a younger lava flow, which is following its exact same path. That young flow proceeds to cover the old flow all along its length . . . until it reaches the hilltop, where it stops and cools (perhaps because the eruption ends). Well now you have a situation where the front of the flow appears older than the top of the flow. But a study of the lava layers would reveal the true story.

QUESTION:

My daughter and I read one of your magazines several months back, and it gave a formula using vinegar and salt to clean coins. My daughter thought that would be a fun science project for school, but we can’t locate the magazine. Could you please email us with the scientific formula and amounts of each we would need to clean dirty coins?!

Thank You,
Pam C – 4th Grade Parent

REPLY:

Barbara Eaglesham wrote up this activity for the February 2000 issue of the magazine – Treasure Hunters.

Here’s what you’ll need:

ceramic bowl
small glass
vinegar, lemon juice, tomato juice, baking soda
9-volt battery
2 pieces of insulated copper wire (about 6 cm long), with clips on both ends

Directions:

For a slow treatment, put some pennies in the ceramic bowl, add enough vinegar to cover the pennies, and soak them overnight. The next day, rinse the coins and polish them!

For a faster "solution," add three tablespoons of baking soda to a small glass of water, stir well, and let sit until it is clear. Clip one end of one piece of insulated copper wire to the 9-volt battery’s (+) terminal. Put the other end in the liquid. Clip the other piece of wire to the (-) terminal. Now attach the wire already attached to the (-) terminal to a tarnished penny. Submerge the penny and the clip in the glass of baking soda solution. Bubbles of hydrogen gas will come off the penny. Bubbles of oxygen will come off the wire attached to the (+) terminal. After a minute or two, remove the penny and notice that the tarnish is gone. This is how archaeologists clean metal artifacts from shipwrecks, except they use a special electrical instrument instead of a battery.

QUESTION:

Two questions:

1. Which delicious red fruit has seeds on the outside?
2. Which is the only family of fruit that does not ripen after plucking?

Haritha, 7 years old

REPLY:

Ha! Easy!

Question 1) Which delicious red fruit has seeds on the outside?

Answer . . . a strawberry!

In fact it’s the only "fruit" in the world to have that characteristic. But, and here’s something to think about, the strawberry may not be a berry at all, and may not even be a fruit. The very definition for a "fruit" states that it is "the matured ovary of a flower, containing the seed." In other words it’s "a fleshy covering of seeds." A strawberry, however, is just the opposite. The strawberry is actually the enlarged end of the plant stamen, although it is sometimes classified as an aggregate fruit (a fruit that develops from several ovaries of a single flower).

Question 2) Which is the only family of fruit that does not ripen after plucking?

I believe the answer is two-fold. A cherry is one answer. Farmers allow them to ripen on the tree before they are picked!

The other answer is figs, for the same reason!

QUESTION:

How does water evaporate?

Thanks,
Blondie

REPLY:

First, we have three states of matter. Solid, liquid, and gas. Evaporation is the process where a liquid, like water, turns to gas. So how does that happen?

Liquid water is really a bunch of water molecules (two hydrogen atoms and one oxygen atom bonded together) really close together; if you had wonder-woman eyes, you could see that these really close water molecules are actually whirling about randomly. The fact is, though, that when water molecules are really close together, they tend to attract one another. (This force appears to be electrical in nature). But if you heat the liquid water, the molecules start moving apart. The hotter the liquid water gets, the more rapidly the water moves about – until the molecules get so excited that they escape (or evaporate) from the liquid and flee into the air, where they become water vapor. (Remember heat rises).

As the water vapor rises it cools and collects (condenses) into clouds. When clouds get over-saturated with water molecules, they form cool liquid rain, which gravity pulls back to earth – until the sun heats up the water, and the process (the water cycle) starts over again.

QUESTION:

How many moons does Jupiter have?

REPLY:

As of January 2001, Jupiter has 28 moons, 10 of which were discovered in January 2001. Saturn has 30 moon, if scientists continue to discover more Jupiter moons, then Jupiter will be the moon king of our solar system.

QUESTION:

How much would I weigh on Uranus? And how would I change that weight to kilograms?

REPLY:

Uranus is a funny planet. Although it is the third largest planet in our Solar System, having an equatorial diameter four times that of Earth’s, most of what we see is atmosphere. Beneath that atmosphere is rocky body roughly the same size as the Earth, though slightly smaller. The specific gravity of Uranus is 0.9 times that of Earth, so if you were to stand on Uranus’ surface, your weight would be 0.9 (0.903 to be precise) times your weight on Earth. If your weight is 100 pounds on Earth, your weight would be 93 pounds on Uranus. To change your weight from pounds to kilograms, just multiply by 0.45.

If you’d like to explore how your weight would change on different planets, go to the following web site sponsored by NASA and Montana State University:

http://btc.montana.edu/ceres/html/weight.html

QUESTION:

How do we from Earth see Venus when it is rising in the east?

REPLY:

Great question. Venus is an "inferior" planet, meaning it orbits the Sun inside the orbit of the Earth. If Venus is low to the horizon in the east shortly before sunrise, then we are seeing Venus when it is either moving away from inferior conjunction (the point in the planet’s orbit when it is closest to Earth – between the Earth and the Sun) or moving toward superior conjunction (the point in the planet’s orbit when it is farthest away from Earth – opposite the Earth from the Sun). When Venus is near inferior conjunction, we see the planet as a crescent. When Venus is near superior conjunction, we see the planet’s disk nearly fully illuminated.

If Venus is already very high in the morning sky before sunrise, then the planet is near the extreme limit of its orbit as seen from Earth – at a 90 degree angle with the Earth and Sun – a time when we would see the planet near or at half-phase.

QUESTION:

I will be teaching StarLab in our school district beginning Monday. What I need is the Native American Legend about Polaris, Big Dipper, and Little Dipper. I know that’s a lot to ask, but if you would like to email me that’s fine.

REPLY:

According to The New Patterns in the Sky by Julius Staal, Polaris is "central" to an American Indian Legend dealing with the Bear Hunt of the Iroquois and Mimnac Indians of Eastern North America.

Corona Borealis is the Bear’s Den. The Bowl of Ursa Major is the Bear. The Bear is being pursued by seven Indians (three of which are stars in the Dipper’s handle; and four of which are stars in Bootes – Eta, Alpha, Epsilon, and Gamma). The double star Alcor and Mizar is the Indian Cook (Mizar) who is holding a Cooking Pot (Alcor). Upon leaving the Bear’s Den (Corona Borealis) in the spring, the Bear is pursued by the seven hunters. The pursuit continues around the sky (centered on Polaris) until some of the hunters become "lost" (when those stars set) – and until the Bear dies in the autumn. After the Bear dies, the hunters watch the subsequent movement of the bear’s skeleton (seen as the Bear on its back – when the Big Dipper appears upside down) through winter. The hunt begins again in the spring, when the Bear is once again upright and ready to emerge from its cage.

QUESTION:

I have been asked to explain the formation of icicles and conditions necessary for their formation in detail and would appreciate any help!

REPLY:

Icicles form when snow melts along, say, the roof edges on a structure. In this case, heat, rising from the attic, causes snow on the roof to melt. As the snow melt flows down the roof, it encounters the cold surface of the roof over the eaves, and it freezes when the roof surface temperature dips below 32° Fahrenheit. When temperatures outside are fluctuating around 32 F, snow can melt naturally, particularly if the roof concerned is oriented toward the sun. As the snow melts, the icicles are created in layers. Water drips down the icicle and freezes in progressive layers rather than being frozen all at once. But here’s a press release I recently came across from the Memorial University of Newfoundland . . . enjoy!

Research with a Pattern
by Tanya Bolduc

When Dr. John de Bruyn woke up one morning to discover that an ice storm had deposited a series of icicles in a strikingly uniform pattern along his clothesline, he quickly went in search of his camera. It was a photo opportunity not to be missed.

But Dr. de Bruyn is not a professional photographer. He’s a physicist and professor in the department of Physics and Physical Oceanography at Memorial. For Dr. de Bruyn, who studies patterns and complex dynamics in non-equilibrium systems, the icicles that invaded his clothesline were a wonderful example of the kind of phenomena that figure in his research.

"These icicles were evenly spaced about one inch apart from each other. That caught my attention," explained Dr. de Bruyn. "I devised some laboratory experiments related to this particular phenomenon and worked out a theory that explained it. You see, water is heavier than air. A layer of water sitting above the air will want to fall down. But for this to happen the layer has to bend, and because of surface tension, this costs energy.

"The competition between gravity pulling the layer down and surface tension trying to keep it flat leads to the formation of evenly-spaced ripples. These ripples freeze, and become the roots of icicles. That’s why the icicles are evenly spaced."

Dr. de Bruyn’s research goes far beyond icicles. There is very little free space in the lab where he is currently conducting half a dozen diverse experiments in the area of pattern formation.

QUESTION:

Why are peaches fuzzy? I’ve been wondering this for a while. Please respond.

REPLY:

Let’s start off with a bit of trivia. First, did you know that if it weren’t for the efforts of an ambitious Swedish scientist named Carolus Linnaeus (who catalogued all known kinds of organisms and minerals), we might never know the true lineage of the peach? In the late 1700s, Linnaeus devised a system of naming organisms that is still used today. Through this scientific system it was revealed that Prunus persica actually belonged to a larger family of organisms called Rosaceae. Translation: the peach is a member of the rose family!

Why are peaches fuzzy? Well, first another first (?) . . . did you know that peaches are fuzzy nectarines? They come from identical trees. Nectarines often originate from peach seeds, and peaches may come from nectarine seeds. Botanists are unsure of which originated first.

Now, why are peaches fuzzy? The real answer is that no one knows for sure but a few theories exist! It’s possible that the fuzz helps the peach defend itself from various threats. Some feel the fuzz was developed to give the fruit more resistance to insects and diseases. Another theory is that the fuzz protects peaches from sunburn and potential water loss.

QUESTION:

I am working on a science project about plants. The title is "Can Food Coloring Change the Color of a Flower?" What are some good websites for my research? Also, what are the tiny hairs on a root called?

REPLY:

1. See the activity section on the following Web site: www.angelfire.com/ma/1stGrade/pageplants.html.
2. These web sites will give you some ideas on how to do the experiment: www.madsci.org/experiments/archive/887562625.Bi.html, www.iit.edu/~smile/bi9703.html, and www.sciwhat.com/article1009.html.
3. The hairs on the root are called . . . root hairs! Root hairs are long tubular outgrowths formed by specialized cells in the epidermis of the root. By growing out into the soil, these hairs increase the area of contact between the plant and the surrounding soil. They are believed to increase plant access to soil nutrients and water, although experimental evidence is sparse due to the technical difficulties of studying these single cells. In many plants they also interact significantly with soil microorganisms. An example is the infection of legume root hairs by beneficial, nitrogen-fixing bacteria (Rhizobium species).

QUESTION:

What are the variables to consider when determining in which liquids an ice cube floats? Is the only consideration the density of the liquid?

Thanks,
Jonathan

REPLY:

I believe you want to investigate the Law of Flotation and Archimedes’ Principle.

The weight of a floating body is supported by the fluid on which it rests; it is bouyed upward by a force equal to its own weight. The buoyant force that a liquid exerts on a body is equal to the weight of the liquid displaced. Therefore a floating body displaces a weight of liquid equal to its own weight.

A 5,000-ton steamship can float – because it is wide enough to displace 5,000 tons of water.

Since the buoyant force upon a body is equal to the weight of the fluid it displaces, heavier fluids will exert a greater buoyant force upon a body than light ones. That’s why a ship will float higher in salt water than in fresh water – because the salt water is denser than fresh water. For the same reason, iron, which will sink in water, will float in mercury.

QUESTION:

I am doing a project on Jupiter and I am having trouble finding the average daytime and nighttime temperatures of the planet. I also can’t find the origins of the names of the galileo moons. I would appreciate your help.

From,
Jonny

REPLY:

The temperature on Jupiter varies with height. But let’s say you want the temperature at the 1-bar level (the average pressure of the atmosphere at the Earth’s surface). The temperature at that point would be 165s Kelvin, which you can convert to Centigrade by subtracting 273.15. The temperature at the hypothetical rock-ice core of this gas giant is 20,000s Kelvin! The day-night differences, especially near the interior of Jupiter, is negligible. The rock-ice core is surrounded by so much gas and pressure, that the temperature is virtually the same. Also, unlike the earth, Jupiter emits its own stored energy. Had Jupiter been 10 times more massive, its internal temperature might have risen high enough to trigger nuclear fusion – and become a little sun!

The four classic Galilean Moons are named Io, Europa, Ganymede, and Callisto. The names come from Greek Mythology. Remember, in Greek mythology Jupiter is Zeus. The following is from NASA planetary’s nomenclature page:

IO – Io was a river nymph whose beauty attracted Jupiter. He fell in love with her, and seduced her. Hoping to hide his affair from the eyes of his wife, Juno (Hera in Greek mythology), Jupiter covered the world with a thick blanket of clouds. The painting "Jupiter and Io" by the 16^th century Italian Renaissance artist Correggio, shows Jupiter in the form of a cloud planting a kiss on the cheek of an ecstatic Io.

Juno wasn’t that stupid. The cloudbank aroused her suspicions (Jupiter was known for having affairs, after all), so she came down to Earth from Mount Olympus and started dispersing the clouds.

When Jupiter realized that Juno was about to find him and Io, he quickly changed Io into a heifer. All that Juno found was Jupiter innocently standing next to a white cow, swearing that he had never seen the cow before, that it had suddenly appeared out of the Earth. Juno wasn’t fooled. She admired the cow, and asked Jupiter if she could have it as a present. Jupiter had little choice but to agree.

Juno now started on a campaign to permanently separate Jupiter and Io. First, she sent Io the cow away under a guard. Jupiter arranged for Io to be rescued and set free. Next, Juno set a gadfly to torment and sting Io, a terrible torture for a cow. Io tried desperately to escape the gadfly, and ended up wandering around the world. Her wanderings were commemorated in the names of many geographical features: the sea that Io the heifer swam across is named after her (the Ionian Sea), as is the Bosporus strait (which translates to "fording of the ox"). Io eventually found her way to Egypt, where, after Jupiter promised to no longer pursue her, Juno returned her to human form.

EUROPA – Europa was a Phoenician princess whose story begins with a dream. In Europa’s dream, the continent Asia argued that since Europa had been born in Asia she belonged to Asia. The other continent, which had no name, said that where Europa was born was not important, and that Jupiter would give Europa to the nameless continent.

In the morning, Europa went off with her companions – a group of young ladies – to gather flowers by the sea. Jupiter noticed the lovely group. He was especially taken by Europa, who was the prettiest of the maidens.

Jupiter’s ideas on how to court a young lady seem a trifle unusual – he approached the group disguised as a white bull. The bull was beautiful, gentle, smelled of flowers, and had a lovely musical moo. Of course, all the maidens rushed to stroke and pet it.

The bull laid down in front of Europa. She slid on to its back, perhaps expecting a gentle ride. Instead, the bull charged off, plunged into the sea, and swam away from the shore. This scene is the subject of a painting by 16^th century Italian renaissance painter Titian, "The Rape of Europa." They were soon joined by a procession of gods, making Europa realize that the white bull must also be a god. She pleaded with the bull for pity. Jupiter told Europa that he loved her, and that he was taking her to Crete. Upon arriving in Crete, Jupiter returned to his usual shape, throwing the bull’s shape into the heavens where it became the constellation Taurus. Juno was distracted with other matters during this period, so she never punished Europa for having an affair with Jupiter.

Jupiter promised Europa that she would bear him many famous sons. Europa bore Jupiter 3 sons, including Minos, legendary ancestor of the Minoan civilization, the first European civilization. Eventually, Charlemagne named the continent which he had conquered Europe – giving a name to that nameless continent.

GANYMEDE – According to the legend, Jupiter’s attention was caught one day by the beautiful Trojan boy Ganymede, whom he saw playing on Mount Ida on the island of Crete. He snatched the boy up, and brought him back to Olympus to serve as the cupbearer of the gods . . . a position, incidentally, already held by his own daughter Hebe. The kidnapping is the subject of this 5^th century B.C. terra cotta statue of Jupiter and Ganymede.

CALLISTO – The nymph Callisto was a favorite companion of the virgin goddess Diana. Callisto had vowed to remain chaste, and to follow in the ways of Diana. She accompanied Diana while hunting and was her constant companion. Jupiter caught a glimpse of the beautiful Callisto and, of course, fell in love with her. Knowing that Diana had warned Callisto of the deceitful ways of men and gods, Jupiter cleverly disguised himself as Diana ("Jupiter in the Guise of Diana and the Nymph Callisto," a painting by the 18^th century artist Francois Boucher, illustrates this scene). He then seduced Callisto, and Callisto conceived a child.

When Callisto’s condition was revealed to Diana by jealous competitors for Diana’s attentions, Callisto was forced out of the company of Diana. She bore a boy child named Arcas. When Jupiter’s wife Juno saw this evidence of Jupiter’s infidelity she became enraged, and changed Callisto into a bear. Callisto was ashamed and afraid, and fled into the woods, not to see her son for many years.

One day, when Callisto’s son Arcas was a young man, he decided to go hunting, and went into the woods where his mother Callisto lived. Callisto saw her son, whom she had not seen for many years. She forgot she was a bear, and rushed forward to embrace her son. Arcas only saw a bear rushing down on him. He lifted his bow and shot an arrow at the beast. At the last moment Jupiter intervened and placed Callisto and her son in the heavens as the constellations Ursa Major and Ursa Minor, the big and little bears. Parts of these constellations are also known as the Big Dipper and the Little Dipper.

QUESTION:

What is immunofluorescence and how it is done?

REPLY:

Immunofluorescence is a laboratory technique scientists use to identify specific antibodies, usually in blood. Antibodies are a protein produced by the immune system in response to the presence of an antigen — a substance that the immune system recognizes as a threat. The presence of an antigen, then induces the formation of antibodies, which defend the body against substances identified by the immune system as potentially harmful. People diagnosed with AIDS, for instance, suffer a breakdown of the immune system.

Although the exact Immunofluorescence technique varies, here’s how it is usually done. A frozen section of mouse liver (or other substance) is cut and placed on a microscope slide. A small amount of the person’s blood serum (part of the liquid portion of blood, which contains the antibodies) is placed over the substance and then washed away. A fluorescent dye is then applied. Antibodies in the dye will combine with any human antibodies, producing clumps of dye that will be visible under ultraviolet light in a microscope.

If you really want to know how it is done, and see an image, go to www.cshl.org/labs/spector/immunofluorescence.html.

QUESTION:

Do plants react to different lights and if so, how?

REPLY:

Plants use light energy to collect carbon dioxide from the atmosphere and convert it to chemical energy in the form of sugar — a process known as photosynthesis. The products of photosynthesis serve to nourish the plant and enable it to release oxygen. According to Homegrown Hydroponics, Inc., plants use only the spectrum of light that is visible to the human eye. Although the light appears white, it is actually a mixture of all the colors of the rainbow. Pigments, which are the light harvesting units of the plants, absorb certain colors of the spectrum and reflect the rest. Chlorophyll, the main pigment used in photosynthesis, absorbs light in the violet and blue wavelengths as well as in the red, leaving green the color we see. Photosynthesis can also occur indoors, providing the artificial light source used supplies the necessary spectrum and intensity. Wide spectrum fluorescent, metal halide, and high pressure sodium are the types of lights most widely used for indoor growing.

QUESTION:

What happens to the dust / gas between the protosun and the protoplanets?

REPLY:

Great question. Five billion years ago a cloud of hot swirling dust and hydrogen gas gave birth to our Sun and planets. As the cloud spun and collapsed inwards it flattened into a central mass with a surrounding disk. Dust and gases in the disk formed small condensations each spinning about its own center. Gravitation condensed and heated the central mass, which ultimately became our Sun. Wind from the newly ignited star blew away leftover dust and gas in the vicinity of the inner condensations, leaving the rocky inner planets: Mercury, Venus, Earth and Mars. In the outer regions of the disk, the solar wind was weaker. The remaining dust and gas condensed into the larger gaseous planets: Jupiter, Saturn, Uranus and Neptune.

If we look closer at what transpired in the primitive Solar System, dust grains broke apart into molecules, and they in turn into excited atoms. The region closest to the protosun would have had the densest concentration of these atomic particles, so collisions between the particles would have been great. That also means the region would have become filled with extremely hot gas – much hotter than the regions farther out from the protosun, say, out by the orbit of Saturn. So, as the dust and gas began to contract, the outer regions of the primordial Solar system cooled first.

"What’s amusing," says astronomer Eric Chaisson, "is that, although there were plenty of interstellar dust grains early on, nature saw fit to destroy them only to rebuild them again later."

QUESTION:

What’s biomineralogy?

REPLY:

Biomineralogy is, basically, the ability of living organisms to form minerals. What’s interesting is that microorganisms, or bacteria, turn out to be remarkably potent agents of biomineralization. These small wonders manage to form an enormous variety of minerals, carbonates, phosphates, oxides, sulfides, and silicates, as well as silver and gold!

Grant F. Ferris, assistant professor at the University of Toronto, is an expert in the field. He says that biomineralogy plays a major role in reshaping the Earth on a global scale. For instance, the chemical weathering of continental rocks are influenced by microbial biomineralogy. By understanding the processes that drive biomineralogy we may find ways to, say, prevent contaminants from polluting natural water sources.

Alas, not all microbial-biomineral interactions are beneficial. In humans, some microorganisms produce kidney stones. And some bacteria can lead to severe problems inside water-cooling towers and heat exchangers. The same microorganisms can plug water wells with rusty slime. Others are notorious for corroding oil and gas pipelines, as well as refinery storage tanks and steel-reinforcement bars within concrete.

Anyway, I’ve just etched the surface of this fascinating field of study. Hope the answer helps.

QUESTION:

What does "Sol" refer to?

REPLY:

Sol is another name for our Sun, the big bright thing in the daytime sky. Our Sun is a star – just like one of countless thousands that we see lighting up the night sky. It’s so bright because it’s so close. If we put our Sun, Sol, at at the distance of the other stars, it too would be just a tiny pinprick of light.

Another way to look at the situation is to think of all the stars in the night sky as suns. Our sun, Sol, is a very average sized and aged star. Just like people, stars come in a variety of sizes, some large, some small, some average. Our sun is average. And, just like people, some stars are old, some are young, and some are middle aged. So good ‘ol Sol is middle aged.

QUESTION:

Thank you for helping my brother with his project. I was wondering if you might be able to help me?

I am doing a project on clouds. I was outside the other day and found a halo around the sun. I was wondering if you could tell me how the halo was formed when there was not any clouds? I was trying to find out how cold the clouds actually get. Would you happen to know? I was thinking about how the airplanes fly through the clouds and wondered if the airplane actually gets colder because it is in a cloud? I would be happy with any information that you might have. Thanks for your help.

P.S. My brother says to say thank you too!

REPLY:

Well, these are great questions. The halo around the Sun is called a 22 degree halo. I’ll explain why it is called that in a moment. But first, believe it or not, there were clouds in the sky when the halo formed. They are called cirro-stratus clouds, which can be so thin that they can go completely unnoticed. In fact, seeing the halo is how you know the clouds are present!

Cirrostratus clouds generally form around 20,000 to 25,000 feet in altitude – where some jets fly. And the clouds are very cold indeed, being made up of tiny ice crystals. These ice crystals are long and hexagonal shaped, like that of a pencil. In fact, they are called pencil crystals, though you would need a microscope to see them.

When sunlight shines through this layer of cirrostratus cloud, it penetrates the transparent crystals, which, like a prism, bend the light by an angle of 22 degrees. That’s why you see a 22 degree circular halo around the circular Sun.

The temperature at about 25,000-feet altitude is about -50 degrees Fahrenheit on average. That’s cold. So, yes, jets do get cold up there, but fortunately the cabins are temperature controlled (they use the heat of the engines), so everyone can fly in comfort.

QUESTION:

What is the compostion of glow sticks? How do they work?

REPLY:

Excellent question, especially since I just returned from using some on a volcano!

These products generate light when two chemical compounds are mixed together. The process is known as chemiluminescense. So, inside the glowsticks is essentially a liquid chemical solution. To keep the reaction from occurring prematurely, the two compounds are kept separate by storing one in a very thin capsule, which is broken by flexing or bending the product tube. The snapping motion converts energy directly to light without heat, flame or spark.

Now, here’s a mouthful from Q-Lite, Inc.: "The thin capsule contains dilute hydrogen peroxide in a phthalate ester solvent. When mixed with the surrounding solution of phenyl oxalate ester and a fluorescent dye (such as 9,10-bis-(phenylethynyl)anthracene for green), the hydrogen peroxide oxidizes the phenyl oxalate ester to a peroxyacid ester and phenol. The cyclic peroxy compound is unstable and gives off energy to the dye as it decomposes to the very stable carbon dioxide. The fluorescent dye radiates this energy as light."

And, just in case you are wondering, the liquid chemical light source is non-toxic, non-corrosive and non-caustic. To learn more about lightsticks, I suggest you go to the following Web Site: www.qlight.com/FAQ.htm

QUESTION:

Is there really a Planet X?

REPLY:

Yes, Planet X is . . . well, was, real, and still may be real. Actually there were Planets X. I would consider the first Planet X to be what we now call Neptune. You see, Neptune was really a mathematical discovery. After William Herschel discovered the planet Uranus with his telescope in 1781, astronomers noticed that something peculiar was happening to the planet in its orbit – namely it was being pulled and tugged (perturbed gravitationally) by an unseen object beyond its orbit. And that pulling and tugging was probably caused by an unknown planet – Planet X. Mathematicians then analyzed these perturbations and made predictions as to where they believed the unknown planet would be in the sky. The mathematicians selected astronomers to look for the planet, and that’s how Neptune was ultimately discovered – right where the mathematicians predicted it would be.

The story didn’t end with the discovery of Neptune. Neptune, it seemed, was also being pulled and tugged by some unknown object beyond it. So began a systematic search for a trans-Neptunian planet – a planet beyond the orbit of Neptune – a Planet X. A dedicated photographic search for the new planet was undertaken at Lowell Observatory in Arizona. And, indeed, a new planet was discovered by Clyde Tombaugh in 1930. Its name became Pluto.

Ironically, Pluto appears too small to cause the observed perturbations of Neptune. So a new search for yet another Planet X was undertaken by numerous astronomers over the years, but nothing of any note has yet been found. Astronomers now wonder if there was once a planet that perturbed Neptune and Pluto but has since moved far away. There are other complications and arguments, but I won’t go into all of them here. So, suffice it to say that Planet X is indeed "real" if only to mean that there may be an unknown planet in our Solar System that exists beyond the orbit of Pluto.

QUESTION:

I would like to know why in the world feet stink? Is there any reason at all? I am just wondering because no matter how much I scrub and scrub my feet they just keep smelling!

REPLY:

What a wonderful question. First, there’s nothing to be ashamed of. About one in five Americans admit on surveys that their feet stink. "Foot odor" occurs when bacteria eat the sweat that accumulates on your skin. Actually, your sweat doesn’t cause the foot odor. It’s the bacteria excreting a waste product that has a strong odor.

Now, everybody has these foot-clinging bacteria. In fact, sweat-eating bacteria are all over our bodies. So why do some people’s feet stink and others’ don’t? Our feet can be sweaty indeed.

Each foot contains 250,000 sweat glands and can produce about a pint of sweat in a day – more than any other part of the body. But unlike on other parts of our body, the sweat on our feet cannot easily escape into the air. It gets trapped in our socks and shoes. And bacteria love dark, damp environments.

So, anyone wearing shoes and socks has foot odor to some degree. But some people’s feet sweat more than other’s. It’s a genetic thing – something that makes us individuals. You’ve probably noticed that your feet smell differently on different days, and that’s because you sweat different amounts on different days.

To reduce foot odor, you need to decrease the amount of sweat that collects on your feet and in your shoes. During the day, you can place Dr. Scholl’s Odor-Eaters in your shoes. These activated charcoal pads separate foot bacteria from the sweat. When you get home, try washing your feet with strong anti-bacterial soap, wear clean socks, and don’t wear the same shoes everyday – give a pair of shoes 24 hours or more to air out before wearing them again. Be also sure to wear well ventilated shoes or sneakers, and also Wick away socks under your normal clean cotton socks. So give all this a try and good luck. If all else fails, and, as a last resort, you could see a foot doctor who could prescribe medication to help reduce the sweating.

QUESTION:

I am a 7^th grader and wanted to know what chemical erosion was? A ranger at a nearby state park told me about chemical erosion and the best example I could come up with was acid rain. Is that good and are there other types?

REPLY:

Great question. I’ll give you a perfect example of chemical erosion, something you see almost everywhere . . . well, at least you do where I live . . . RUST.

You see, there are two types of changes that you can make to matter. One is a physical change. For instance: take an iron bar. If you heat it, the iron bar will expand. It’s still iron, but you have now changed its size and shape. But a chemical change (the rusting of iron) actually changes the nature of the substance – meaning the atoms in the iron rearrange themselves to form a new substance (rust). So yes, acid rain does the same rearranging on the chemical level. The sulfurous and acid environments around volcanoes can produce chemical change to the surrounding air and rocks. But here’s a good one for you . . . it’s also gross: the increased acidity caused by vomiting can lead to severe chemical erosion of the enamel surface of your teeth, especially in the upper jaw. When this enamel is eroded the softer inside part (dentine) is exposed. So, what do you do to counteract the chemical imbalance created by vomiting? According to the Eating Disorders Resource Centre, "Rinse immediately after vomiting with sodium bicarbonate (one teaspoon to a half glass of water – spit it out, don’t swallow it!) or at the very least, plain water). Daily brushing with fluoridated toothpaste and flossing are essential – however opinions vary on whether brushing immediately after vomiting is damaging so it might be best to consult with your dentist for the latest clinical advice." Good luck.

QUESTION:

How do those toy glowsticks work?

REPLY:

Well, well, well. I love this question, because I’m just about to go out and buy a few boxes of Cyalume ® and Snaplight ® Lightsticks. These products (and others like them) generate light when two chemical compounds are mixed together. The process is known as chemiluminescense. So, inside the glowsticks is essentially a liquid chemical solution. To keep the reaction from occurring prematurely, the two compounds are kept separate by storing one in a very thin capsule, which is broken by flexing or bending the product tube. The snapping motion converts energy directly to light without heat, flame or spark.

Now, here’s a mouthful from Q-Lite, Inc.: "The thin capsule contains dilute hydrogen peroxide in a phthalate ester solvent. When mixed with the surrounding solution of phenyl oxalate ester and a fluorescent dye (such as 9,10-bis-(phenylethynyl)anthracene for green), the hydrogen peroxide oxidizes the phenyl oxalate ester to a peroxyacid ester and phenol. The cyclic peroxy compound is unstable and gives off energy to the dye as it decomposes to the very stable carbon dioxide. The fluorescent dye radiates this energy as light."

And, just in case you are wondering, the liquid chemical light source is non-toxic, non-corrosive and non-caustic. To learn more about lightsticks, I suggest you go to the following Web Site: www.qlight.com/FAQ.htm

QUESTION:

Dear Scientist –

In the table of elements, is there an element called zircon? And why are scientists worried about other species on Earth?

REPLY:

1) No, but there is Zirconium, which is a hard, lustrous, grayish-white metal. The mineral has been known since ancient times, but the existence of elemental zirconium was not known until the late 18^th century. It is abundant in some stars and is a component of the sun and meteorites.

2) Well, life on Earth is very diverse. We do not know most of the species, what their purpose is, how they interact with nature, how they help to preserve the places where they live. The sad fact is that we are depleting our natural resources, killing off countless species that we have not even had a chance to study. Did you know that humans (and some apes) are the only species that knowingly destroys its environment, which is essential to the species survival? All other species live in a certain harmony, they keep nature in balance. We upset the balance of nature by trying to control it. So perhaps we have a lot to learn from other species – before we wipe them out. Can you imagine a world with no butterflies, flowers, grass, insects, animals? Where would you go camping? What excitement is there in only seeing humans? Think of a concrete world with no other animals? No cats, no dogs, no fish, no parrots, and so on? Can you? What good is the wilderness? Give the matter some thought.

QUESTION:

How many moons does Jupiter have? How hot is Jupiter?

REPLY:

1) Good timely question. Jupiter’s family of 18 moons recently got bigger! The discovery of 10 new moons came last winter after astronomers using the University of Hawaii’s 2.2-meter telescope last November found many new possible moons. Brian G. Marsden (Harvard-Smithsonian Center for Astrophysics) had to sort out the orbits (that takes a lot of calculating) and finally confirmed that 10 of the objects were indeed new Jovian satellites. So, how many moons does Jupiter have? At the moment 28! One of the 10 moons orbits Jupiter 12 million kilometers from the planet. But here’s something cool – the other nine moons orbit Jupiter backwards at about 22 million kilometers from the planet.

2) Well, I couldn’t escape with a bunch of simple questions. Actually, this one is simple, since all I have to do is look up the answer in a table. But the non-simple aspect is the understanding of "degrees Kelvin" and also of the fact that Jupiter’s temperature varies depending where "you" are.

The temperature of Jupiter varies from 25,000 Kelvin at the center of the planet to 165 Kelvin in a place in its atmosphere where the pressure is equal to that of sea level on Earth.

Now for the conversion factors: A temperature in Kelvin can be converted to one in degrees Celsius by subtracting 273.15 from the Kelvin value. To convert degrees Celsius to degrees Fahrenheit, multiply by 9/5 and add 32. I’ll leave that up to you to determine.

QUESTION:

I am doing an experiment using the bending of light. In the experiment, I stick a penny underneath a plastic cup filled with water. If you look down straight into the mouth of the cup, you can see the penny, but if you cover the mouth of the cup up with say notecards or something and try to find the penny by looking through the sides of the cups, you can’t see the penny. My instincts tell me that the answer to why I can’t see the penny through the side of the cup has to do with the angle with which I am looking and the refraction of light rays in water – I just can’t put it together. I have found information on looking through the mouth of the cup and why I can see the penny when doing that; I just can’t find any information on looking through the sides of the cup and what happens with the light angles. Could you please help me??

REPLY:

Great question. Actually you are right about refraction, and in this case Snell’s Law applies. Whenever light travels from one medium to another – in this case from water, to glass, to air – the light ray is bent by an incident angle. The index of refraction (r) for water is 1.33, for normal glass it is 1.5, and for air it is slightly greater than 1. Anyway, the formula gets a little complicated, but the point is that, first, and you are correct, if you look at a slight angle into a cup of water with a penny at the bottom, you can see the penny, because the light ray is bent at the interface of water and air placing it in your line of sight – even though your line of sight is not aimed at the penny but at some point away from it. If you remove the water from the cup and look at the same angle you will not see the penny, because it is no longer in your line of sight.

The chance of you seeing the penny is greater looking down into the cup at a slight angle because the surface area of the penny is greater than if it were on its side – which is the case when you look at a penny sideways through water.

The difference in looking at a penny from the side of the glass then is twofold. First, light is being refracted at the water-glass interface (and that angle also depends on the thickness and type of glass) then at the glass-air interface. So it’s a double refraction. Not only that but a penny seen from the side is quite thin, so there’s less area to see. Of course, if you place your eye directly in line with the penny as seen from the side, the penny will disappear because its light is being refracted away from your eye, so you have to shift your gaze slightly in order to see it.

QUESTION:

What happens when the ozone layer around the earth thins as a result of pollution?

REPLY:

First, I’d like to explain that although we often hear about a "hole" in the ozone layer, there really is no "hole," just a depletion of ozone. The measurements are made by satellites and the depletion is best seen over Antarctica in the months of September and October.

This is a timely question because, as of September, NASA scientists have announced that the depletion of ozone (the "hole") over Antarctica in the year 2000 is the largest they’ve seen. The "hole" measures 28.3 million square kilometers (11 million square miles), which is three times the size of the United States. Dr Michael Kurylo, manager of NASA’s Upper Atmosphere Research Programme, told the British Broadcasting Company that "These observations reinforce concerns about the frailty of Earth’s ozone layer."

Why is everyone concerned about ozone depletion? Because the ozone layer protects our planet from harmful ultraviolet radiation (UV) and ozone depletion is believed to contribute to high rates of skin cancer. How strong is the evidence that UV radiation causes skin cancer in humans? Studies in molecular biology has provided us with strong evidence of the link. According to the National Cancer Institute, between 1973 and 1992 the incidence of melanoma, a serious form of skin cancer, increased faster than any other cancer among caucasians in the United States.

Another danger, of course, is that the depletion in ozone could cause global warming. Already, some scientists believe that north polar ice cap could disappear altogether by the end of the 21^st Century. But this is a controversial finding, and other scientists do not agree with the findings.

QUESTION:

What year do you think we will land on Mars?

REPLY:

Excellent question. And a timely one. And since so much of what we do in space depends on NASA and its initiative, I think I’m going to give you a quote (though very non-committal) about what we might expect to see in the near future.

"As world history illustrates, humans are compelled to discover new frontiers. Our exploration of the space frontier has already begun. Robotic missions and new technology are the first steps toward expanding human presence in the solar system. Human missions to the Moon, Mars and beyond may become a reality in the 21^st century, and NASA is leading the way. NASA’s mission to explore continues as we build a foundation of technology, experience, and scientific knowledge. During the first decades of the 21^st century, explorers from Earth could set foot on the Moon and Mars and expand the human frontier."

That’s about as best I can do . . . namely, let you hear it from the horse’s (NASA’s) mouth.

QUESTION:

I am in 6^th grade and I am trying to find out the names of the songs that were on the gold CD that was sent into space. Could you help me? I also am trying to find out the name of the space ship that went up with the CD inside. My teacher has me looking up information at SETI, but I am having no luck.

REPLY:

The record is on the Voyager spacecraft and it contains 87 ½ minutes of music, comprising twenty pieces: Bach’s Brandenburg Concerto No. 2 in F; "kinds of Flowers" (Javanese gamelan); a Senegalese percussion piece; a Pygmy girls’ initiation song; "Morning Star" and "Devil Bird" (Australian horn and totem songs); "El Casabel" (Lorenzo Barcelata and the Mariachi Mexico); "Johnny B. Goode" (Chuck Berry); a New Guinea men’s house song; "Cranes in Their Nest" (Japanese bamboo flute); Bach’s "Gavotte en Rondeaux" from the Partita No. 3 in E Major for Violin; Mozart’s "Queen of the Night" aria, No. 14, from the Magic Flute; "Tchakrulo" (Gregorian chorus); a Peruvian panpies and drum piece; "Meancholy Blues" (Louis Armstrong and his Hot Seven); "Ugam" (Azerbaijan bagpies); Stravinky’s "Sacrificial Dance" from The Rite of Spring; Bach’s Prelude and Fugue in C from The Well-Tempered Clavier, Book 2; Beethoven’s Fifth Symphony, First Movement; "Izelel je Delyo Hagdutin" (Bulgarian bagpipes); Navajo "Night Chant"; Anthony Holborne’s "The Fairy Round" (Renaissance music); Soloman Islands panpies; a Peruvian wedding song; "Flowing Streams" (Chinese ch’in); "Jaat Kahan Ho" (sung by Surshri Kesar Bai Kerkar); "Dark Was the Night" (Blind Willie Johnson); Beethovan’s Cavatina from the String Quartet No. 13 in B flat.

Have fun seeking out the tunes. Oh, and let’s give a big Thanks to William Poundstone who included the story behind the record in his biography of Carl Sagan, who was involved in the selection process.

QUESTION:

How do you weigh someone or something in space? And how would fertilization, gestation and birth in space differ from what would happen on Earth?

REPLY:

Hmmm. I’m not sure if this is a trick question. Ever hear of "weightlessness"? Well, if you are in space you weight nothing. Weight is a product of the downward pull of gravity. So weight is a measure of the gravitational force acting on a body. Your weight, say, on Earth, decreases the farther away you are from the center of the Earth – until you escape the bounds of earth’s gravity and you become weightless. That’s why astronauts float in their space capsules.

What doesn’t change, however, is your mass. The greater the mass, of course, the greater the weight. Your mass is essentially the quantity of matter that makes you . . . you. Let’s look at it a different way. Since there is twice as much water in a quart of water as there is in a pint, a quart of water has twice the mass of a pint.

Now, I have a question for you. How much would you weigh on the Moon? On Mars?

QUESTION:

What would happen to a person that died in space?

REPLY:

Well now. That’s a gruesome thought. You would think that that drifter would be well preserved, like a mummy, but actually, whenever a human being leaves the protective layer of Earth’s atmosphere, he or she is subjected to incredible amounts of ultraviolet and other radiation, as well as cosmic rays. So the body will essentially cook. Now imagine all the micro-meteorite debris sailing through space — the kind of natural debris ejected by comets as they orbit the Sun. Well, a body floating in space is apt to get pelted by these tiny bodies. Of course, in time, the drifting corpse will ultimately be captured by the gravity of some planet. The body will orbit that planet until the orbit decays and it plummets into the planet’s atmosphere as a "meteor."

QUESTION:

What metal weighs the most?

REPLY:

Well, good question. It could also be a trick question. You see, weight is a measure of the gravitational force acting on a body. The measurement depends on the mass of the object, which is numerically equal to the mass of the object in pounds or grams. I say it could be a trick question because let me turn the question around: What weighs more, a pound of feathers or a pound of bricks? The answer is, of course, that they weigh the same.

But let’s look at a different kind of weight — atomic weight. Atomic weight is the mass of a given atom, measured on a scale in which the hydrogen atom has a weight of 1. Since most of the mass in an atom is in the nucleus, and each proton and neutron has an atomic weight of 1, the atomic weight is very nearly equal to the number of protons and neutrons in the nucleus. Therefore, the higher the atomic number, the heavier the atom is. The metal Lawrencium has an atomic number of 103 and is the heaviest element you’ll see on most periodic tables. But the list has expanded greatly through the years. Most recently, the table has expanded to include elements 116 and 118.

QUESTION:

I live in Taranto, southern Italy, I think I saw Comet Linear naked eye yesterday about 6.00 pm. It was like a very bright light in the sky, but faded away in a few seconds. Is it possible to see a comet, even a very bright one, naked eye and in daylight?

REPLY:

I’m happy you are looking for Comet Linear, but, unfortunately, any reports you might have heard about it being visible to the naked eye were not true. The comet would have been visible only in binoculars around the time you were looking. And it certainly could not have been seen in the daylight. Since then, the comet neared the Sun, blew apart, and, essentially, evaporated.

However, it is possible to see very bright comets in the daytime. The last one that was easily visible was Comet West in 1976. Comet Hale-Bopp could be seen right up to the moment of sunrise in a telescope (but not to the naked eye). Maybe we’ll get another one soon. They seem to come about every 20 years.

QUESTION:

What is the oldest animal ever?

REPLY:

Ha! I bet you thought you’d get me with this one. But your question is related to animals, and believe it or not, that includes single-cell organisms like protozoa and worms. So, given that, the answer is simple.

The oldest of Earth’s fossils date to the Precambrian. The Precambrian covers all but the last half billion years or so of Earth’s 4.5-billion-year history. Scientists have found very few Precambrian fossils. But they have found some. Those that they have found are of algae and fungi, and the trails or burrows of worm-like creatures. So, there you have it. Slithering worms are your oldest animals on Earth, and they bored through the Earth some 700 million years ago. Crustaceans, fish, insects, amphibians, and reptiles arrived about 590 million years ago. All these creatures are the oldest animals on Earth. So they also had the best opportunity to evolve.

QUESTION:

How can I make a simple model of the Solar System?

REPLY:

With lots of space . . . ha, ha. Seriously, here’s one for you. If the earth is the size of a pea, then the Sun is 108 pea-diameters wide. (The size of a big beach ball). Place the Earth pea 200 feet from the beach ball, and that’s the distance (on this scale model) between the Earth and Sun. How far away is Pluto on this scale? Over 1 mile.

Here’s another one: If the Sun is the size of a pinhead, the Earth is 1 inch away and measures one-millionth of an inch in diameter. Pluto on this scale would be three feet away, and the nearest star would be four miles away!

QUESTION:

What effect will global warming have on us, and can we do anything to prevent it?

REPLY:

Global Warming is caused by an increase in carbon dioxide and other "greenhouse" gases that reduce the amount of heat reflected from the Earth’s surface into space. The increasing presence of these gases appears to be heating up the Earth’s global temperature. So how does that affect us? Good question. If global warming is really happening (it’s still being debated), then for the person in the street, this means we’ll start to see an increase in the number of days each year that exceed temperatures of 100 degrees Fahrenheit. Now, let’s say you lived in Phoenix, Arizona, where temperatures already reach 120 degrees. Would you like to live in Phoenix when the temperature reaches 140 degrees? 150 degrees? Dramatic temperature changes caused by increased greenhouse gases could also affect the polar ice caps, causing them to melt, which would cause the seas to rise seven feet or more. Some scientists speculate that an increase in global temperature will increase the spread of disease as insects spread north.

I think you get the picture. In fact, don’t be surprised if the next blockbuster hit on the Big Screen is GLOBAL WARMING! You know, some kind of science-fiction or horror story with a lot of screaming people as the world turns to flames during a plague caused by killer bees migrating north into the cities. But don’t let the sensationalism get to you. There’s a lot we still don’t know about average global temperatures. For instance, while some regions of the globe appear to be warming, others are cooling. So go figure.

But people can help the Earth cool down by driving less (or taking public transportation) and using products that do not create greenhouse gases. I recently learned about a car being created in Colorado that uses hydrogen fuel and doesn’t pollute the air. Wouldn’t that be nice!

QUESTION:

My questions are (1) How many planets are in our Solar System? (2) When are people going to visit Mars, and (3) Is the universe expanding or contracting and why?

REPLY:

On the surface your questions might seem simple to answer, but they are not.

1. How many planets are in our Solar System? The classical answer is nine: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto.

That seems simple enough, but here’s the catch. Is Pluto a planet? Some astronomers argue that it is not. They say it is only the largest object of a new class of bodies orbiting the Sun in highly inclined orbits. If that’s true, then our Solar System contains eight planets and a Pluto-type object.

But the answer doesn’t stop there. Some astronomers would argue that only Venus, Earth, and Mars are planets. All the others are either giant gas balls or tiny moon-like objects. Discussions about just what is a planet continue to this day. Of course, the answer has great implications, because we are now finding objects around other suns. Are they "planets" or giant gas balls? Stay tuned . . .

2) Someone in your generation (if you’re in grade school) has a chance of being that lucky adventurer. I’ve seen some estimates from NASA that say we’ll have a human on Mars in the year 2035. I believe that’s very optimistic.

3) Is the universe expanding or contracting? No one knows just yet. The question all boils down to how much matter is in the universe. Right now, astronomers believe that we "see" only about 10 percent of the matter. The other 90 percent is locked up in missing "dark matter," whose presence is implied by an unseen extra source of gravity. This extra gravity tugs on stars at the edges of galaxies, making them revolve too quickly for the amount of matter that we see. So from this observation we infer that a halo of dark matter extends beyond the galaxy’s edge and accelerates the visible matter with its gravitational pull. The amount of dark matter in the universe controls the fate of the universe. There may be enough dark matter in the universe so that its pull of gravity will ultimately slow down the universe’s expansion. After many billions of years, the matter would collapse back in on itself in what’s called a Big Crunch. But astronomers are beginning to be skeptical of this Big Crunch theory. In fact, it appears that the universe contains only about 30 to 40 percent of the matter needed to stop its expansion. If so, the universe will continue to expand forever.

Keep your mind expanding!

QUESTION:

Can you tell me what static electricity is and how I can make a science experiment to test it?

REPLY:

Static electricity is a kind of electricity that, unlike the electricity that powers our television sets and computers (with electric current), is created when certain materials are rubbed together. You’ve experienced static electricity if you’ve ever shuffled across a rug on a cool dry night in your shoes, then touched something metal, like a door handle and received a mild jolt. That’s static electricity. What happens is that by shuffling across the floor, you’re building up an electric charge that is discharged when your finger comes in contact with an opposing charge (the doorknob). You can also see the effects of static electricity by rubbing a balloon against your arm and then sticking the balloon to the wall.

You can find an experiment on static electricity in the March 1998 "Skyworks" issue of ODYSSEY magazine.

QUESTION:

We live near salt water and often see "sea smoke." I would like to know what causes this.

REPLY:

Sea smoke, huh. Here’s what I believe is happening. When there is enough moisture in the air, and there is little or no wind, the air temperature may be lowered to the dew point, at which time the air can become saturated close to the surface of the ocean. If a little breeze is present, further mixing occurs and the saturated air (fog) thickens. When the Sun rises, it heats up the air and the fog dissipates. You probably see this "sea smoke" at the time when the fog is nearly evaporated. A similar situation can occur if an upwelling of cold water beneath the ocean’s surface occurs.

QUESTION:

What makes our seasons change?

REPLY:

Great question. Lots of folks believe that in the winter the Earth is farther away from the Sun than in the summer. But this is not the case. In fact, just the opposite is true.

We have seasons because Earth’s axis is tilted 23 1/2¼ to the plane of the Solar System, which is the imaginary extension of the Sun’s equator through space. So we go around the Sun sort of lopsided. The orientation of the Earth’s axis does not change as the Earth orbits the Sun. It is this tilt of the Earth’s poles that causes the seasons.

When people in the Northern Hemisphere are experiencing winter, the Sun is shining most directly over the Southern Hemisphere. That’s why people and birds head *south* for winter, because it’s warmer! One half a year later, the Sun’s rays will be most direct in the Northern Hemisphere. That’s when we in the Northern Hemisphere experience summer and and people in the Southern Hemisphere experience winter. You can see the apparent "migratory" path of the Sun on many Earth globes. Look for that "infinity" symbol centered on the equator. It’s called the analemma.

Have you ever noticed how low the Sun looks in the winter sky and how high it looks in the summer sky? That’s because as the Earth orbits the Sun, the Sun appears to migrate north and south in the sky. Of course, Spring and Fall (the equinoxes) occur when the Sun appears directly over the equator — so it is half way between summer and fall. That’s when we have "equal" day and night.

QUESTION:

What is in household dust and why it causes allergies. What are some ways you can reduce this kind of dust around the house?

REPLY:

Wow. This one is kind of gross. Your house is full of blind, microscopic creatures called mites (Dermatophagoides pteronyssinus). These tiny arachnids feed on flakes of dead skin that fall onto carpets or rub off in the bed. By day’s end each mite will have dropped about 40 fecal pellets, which we inhale whenever dust is stirred up. Actually, the pellets only carry the agent that causes us to sneeze. The real culprit is an enzyme, called Der p 1, that lies on the surface of mite feces. Mites use the enzyme to digest proteins.

When we inhale Der p 1, the enemy enzyme is recognized by a special antibody, called IgE, that patrols the bloodstream on a "carrier cell." IgE’s job is to bond with Der p 1 and create a foreign antibody. An explosive drama unfolds when IgE’s carrier cell reacts to this bonding by producing histamines. Enough histamines will cause swelling, itching, and sneezing. By sneezing we blow the foreign antibody out of our systems.

How do you reduce this threat? That’s simple. When your parents ask you to vacuum the house or your room . . . DO IT! 🙂

QUESTION:

Why does my skin wrinkle when I stay in the bathtub too long?

REPLY:

The short reply is that we have glands in our skin that secret oils, which keep our skin looking smooth and healthy. When we take a long bath, the moisture-locking skin oil – which keeps our skin supple – comes off in the water; the longer you stay, the more oil that is lost. It takes a while for the glands in our skin to secrete more oil, so, for a while, our skin looks old and wrinkled. Too much bathing with soap also removes the skin’s natural oils. This is the main cause of dry skin. Dry climates make dry-skin condition worse, as can being in other extreme conditions – such as in a swimming pool with lots of chlorine. All of the things I’ve mentioned here can lead to dry, wrinkled skin (even for greasy teens). If for any reason the skin’s top layer turns scaly, that further reduces its ability to retain moisture.

Now, that’s also why moisturizers are very popular. If you’ve been out in the sun too long and your skin becomes "dried-up," you put on these "magic" lotions to help get your skin back on track. Moisturizers are effective remedies because they reduce water loss from the skin and draw moisture from the inner skin layer up into the outer skin layer. Just about all lotions and creams contain ingredients to do this. Substances that reduce water loss by creating a barrier include petrolatum, mineral oil, and lanolin. Substances that attract moisture to the top skin layer, called humectants, include glycerin, alpha hydroxy acids, and lactic acid.

Now, the question is, do you know the "real" leading cause of dry skin? The answer is . . . . . Towels! Ha, ha.

QUESTION:

Why is the Solar System called the Solar System?

REPLY:

What a fun question. The "Solar System" has Latin roots. "Sol" is Latin for "Sun." And "Solar" is Latin for "Of or relating to the Sun." So that takes care of the first half of the problem.

Now, a "System" is a group of interacting members forming a complete whole – like a family. So our Solar System is a family of planets that are gravitationally interacting with the Sun. Thus Solar System.

QUESTION:

Hello, I’m 14 and wondering that if the possibility of finding Near Earth Objects is so low compared to the possibility of one that we see will hit us, why do we even try to find them? Also can you share your thoughts about what you think on the subject?

REPLY:

There’s a good reason the odds are stacked against us. First, astronomers who want to find them don’t have enough telescopes set up across the globe to have a continuous monitoring system. Second, and most importantly, there is not enough government support (moolah) for the effort. There’s a lot of verbal concern by politicians: "Yes, this is terrible. Let’s do something about it." But where’s the money to back up the concern? If an asteroid or comet of a given size hits Earth, the outcome is clear. Perhaps the government is being a little short-sighted at the moment.

But if we do get a global program going, then we could start to cover the entire sky to incredibly faint magnitudes and discover these objects many years before they hit. The idea is to find them when they are still very far away. Once discovered, the threat can be assessed and a solution implemented before the object hits the Earth. You see, all we need to do is nudge the object just a tiny bit when it is far away from Earth; believe it or not, that tiny nudge will alter the object’s orbit enough so that it will miss the Earth completely. Such a tiny nudge doesn’t work when the object is very close to "kissing" Earth.

QUESTION:

I would like to know why is it that we see things in the past? But yet we can’t see them in the future relative to time and space?

REPLY:

Excellent question, for which there is only a partial answer. We see things in the past, because light travels at a set speed (186,000 miles per second). Consider what happens when something is farther than 186,000 miles away. The distance to the Moon is about 250,000 miles, which is 64,000 miles greater than the distance light can travel in one second. In fact, it takes Sunlight bouncing off the Moon about 1 1/3 second to reach our eyes. So we see the Moon as it appears about 1 1/3 seconds in the past.

Now let’s up the stakes. The Sun is about 93 million miles away. When light leaves the surface of the Sun, it takes 8 1/2 minutes to reach us! So we see the Sun 8 1/2 minutes in the past. Other stars and galaxies are even further, so we see objects in the past every time we look at the night sky. It’s a Big Time machine that can bring us views of the past.

But the future? Well, that’s a different matter. On paper, we should be able to see into the future. It’s a simple matter of sign reversal in mathematics. This problem is called "The Arrow of Time," because although we should be able to see into the future, we don’t. The "arrow" points only one way . . . to the past.

QUESTION:

In the sixth grade science text book, the students read about the Alvarez theory of why the dinosaurs died. The text book stated there was evidence in Mexico, and also Iowa. Since we live in Iowa, we were interested in the evidence that was found here, and where it was found in Iowa.

I heard that you have an article in the April 2000 issue called "Crispy Critters," but you don’t mention Iowa, and I haven’t been able to find any evidence linked to Iowa. Could you help me out? Could it be that we just have more iridium in the soil, and that is the evidence?

REPLY:

The impact structure in Iowa is in Manson, and it is the largest known impact structure in the continental states. It has a diameter of about 35 kilometers. Some researchers (like the late Eugene Shoemaker) argue that the dinosaur extinction Cretaceous period 65 million years ago might not have been a single event. Instead, the Earth may have been bombarded by comets or asteroids for hundreds of thousands of years. The dinosaurs and other species would then have been wiped out in steps rather than all at once.

The Manson crater in Iowa was created 65.4 million years (give or take a few tenths) – nearly at the same time. The Manson event was undoubtedly a major catastrophe: the impact released about 1,000 cubic kilometers of ejecta into the atmosphere and shrouded the Earth with a blanket of blackness. Manson ejecta has clearly been identified within the Pierre Shale (Crow Creek Member) of South Dakota and Nebraska. The effects of the shock wave produced by the impact have been tentatively scaled: (1) all combustible material within 200 km would have been ignited, (2) all standing vegetation would have been devastated to 600 km, (3) most terrestrial animals would have been killed by the shock to 1000 km (as far as Montana), and (4) large animals (dinosaurs) would have been knocked off their feet as far as 1300 km. Tsunami-like waves may have surged across the nearby Western Interior Seaway. Considering the extent of the devastation, the terrestrial biota apparently quickly recovered, undoubtedly replaced by migrants from elsewhere on the continent.

Alas, the impactor at Manson would have been too small to have caused a mass extinction at the end of the Cretaceous Period. Manson-size impacts should occur every few million years, so scientists are suspicious that the Manson crater dates so close to Chicxulub. Researchers also suspect that two Russian craters of about the same size as Manson – Kamensk (about 300 kilometers west of Volgograd) and Kara (on the Kara peninsula) – may be roughly the same age. So maybe there was a shower of very large stones that fell from the sky over several hundred thousand years that gradually wiped out the dinosaurs.

QUESTION:

I was wondering why can’t we build a space ship that can travel many many light-years away? Like, for example, to the Orion Nebula, or even to Pluto?

REPLY:

We have built spaceships that have gone very far, even further than Pluto. Some of our early Solar-System explorers, like the Pioneer spacecraft, have traveled beyond Pluto – out to the very edge of our Solar System, toward the gravitational realm of other stars. The Voyager 2 spacecraft has traveled to Neptune and beyond, but Pluto was not positioned well for a rendezvous with it. So we have the technology and capability to send spacecraft to Pluto. In fact, a Pluto Mission is planned. The key for such a mission is to deliver a scientifically useful payload to the distant system at minimum cost, and to do so before the year 2020. So a space mission to Pluto is foreseeable in your lifetime. Traveling to the Orion Nebula is simply just too far. We wouldn’t be around, even traveling at the speed of light, considering that the nebula is about 1,500 light years distant, which means, even traveling at the speed of light, you’d have to wait 1,500 years for the craft to get there. What we need is to find the fountain of youth.

QUESTION:

How far can a praying mantis see?

REPLY:

As far as it wants . . . Just kidding. Actually, in a way, this is true. Like most insects, the praying mantis has a compound eye. The lens system of the compound eye is capable of forming fairly sharp images, so a mantis’ eyes, in the end, mimic what our eyes do. As long as an illuminating source is bright enough, the insect can see it no matter what its distance. For instance, we know that moths can navigate by the Moon. (That’s why they circle artificial lights; they’re used to keeping the Moon to one side of them for direction.) So insects can see an illuminating source at least 250,000 miles away (the distance of the moon). Since the Sun is 93 million miles away, they can certainly see it.

"Seeing" is not a simple concept, though. We really tend to define seeing as something a little bit more than seeing a source of illumination. The question, really, is when does an object come into sharp enough focus that we can perceive detail? We say a person with 20/10 vision has incredible eyesight, because he or she can see at 20 feet what people normally see at 10 feet. I’ve never seen a praying mantis with glasses, so I assume they’ve got pretty normal vision. (That’s a joke). But instead of using feet we’re talking distances in millimeters with insects.

QUESTION

I was wondering, can southern hemisphere constellations be seen from Arkansas? I happened to look out a window recently, and I thought I saw Scorpius. It was around 2:00 am.

And, how can you spot and locate Artificial Satellites?

REPLY

You can see southern constellations from Arkansas. How far south in the sky can you see? Just subtract your latitude from 90 degrees. For example, if you live at latitude 30 degrees north. You can see stars to 60 degrees south celestial latitude. If you live at the north pole (north latitude 90 degrees), you can only see to the celestial equator (0 degrees). If you live at Earth’s equator (0 degrees latitude), you can see the stars in both the northern and southern hemispheres! So you did see Scorpius. The mid-section of the constellation is at about 30 degrees south celestial latitude, a section of sky well visible from your location at that time.

As for artificial satellites, you can see them on any clear night. They simply look like stars moving across the sky. Their brightnesses vary. For instance, the latest fleet of satellites – the Iridium satellites – have highly reflective solar panels. They will sail across the sky shining like a moderately bright naked-eye star, until sunlight glints off their reflective panels – that’s when the satellites will suddenly *FLARE* briefly to outshine the planet Venus. The best time to spot a satellite is shortly after the sun sets. All you have to do is be someplace where you can see the night sky reasonably well; just lie down and look up! If you spend about a half hour under the stars, you should be able to spot several satellites going in various directions across the night sky. For satellite predictions, please go to the following web site:
http://www.skypub.com/sights/satellites/satellites.shtml

QUESTION

Is light related to matter?
– FIChapel

REPLY

The answer is related to an area of physics called QED, or Quantum Electrodynamics. It is the strange and wonderful theory of light and matter, or (more specifically), the interaction of light and electrons. Light is made up of particles. Each little lump of light is called a photon; one way to think of them is as raindrops. As particles of light, photons account for many familiar effects we witness daily – such as light bouncing off a mirror or light bending when it enters air or water. So yes, light and matter are related in a very curious and wonderful way.

****

QUESTION:

What is the oldest thing on earth?

REPLY:

Danish researchers announced in January 1999 that they had found what they think may be evidence of the oldest life on Earth – a signature left by plankton 3.7 billion years ago. But here’s the punch line. It’s not a fossil imprint, like a dinosaur footprint, but a chemical signature in ancient rocks in west Greenland.

All life on Earth is based on the element carbon, and living things make chemical changes to this carbon. The Danish team looked at two particular variants, or isotopes, known as carbon-12 and carbon-13. The group examined microscopic globules of graphite – which is pure carbon – from some metamorphic rocks known to be 3.7 billion years old and known to have once been seafloor sediment. The levels of carbon-12 and carbon-13 were similar to those found in more modern deposits, which scientists know include the waste products and remains of plankton. So the evidence looks good

QUESTION:

Why is Earth the only planet that has living things on it?

REPLY:

Ah! Interesting question. But the real question should be "Is Earth the only planet that has living things on it?" Sure, there aren’t any civilizations of human beings on any other planets in our Solar System, but life has many forms. Bacterial life could, and I believe, probably does exist on Mars, Jupiter’s moon Europa, and possibly Saturn’s Moon Triton. Life on these worlds is a real possibility.

Big creatures, such as us, exist as we do, because of Earth’s distance from the Sun (93 million miles). All the other planets are either too close to the Sun (so too hot), or too far away (too cold) for human life to exist without exterior protection. The surface of Venus, for instance, is hot enough to melt lead. And although some regions on Mars can have reasonable daytime temperatures (ones that we could stand) the planet’s nighttime temperatures can plummet to -100 degrees C. There are many other factors, of course, but that would require an entire course in the history of the Solar System. So, for now, be glad you’re on Earth.

QUESTION:

What are magnets? Can humans be magnets?

REPLY:

Well, I have to admit I’m attracted to that question (joke). In simple terms, a magnet is a mass of iron that has the ability to attract or repel other masses of iron. The attraction happens on the atomic level. If you could see the iron’s atomic structure with all its electrons moving about, you’d see that the tiny particles orient themselves in the direction of Earth’s magnetic field. So all magnetic objects have two poles (like Earth) – north and south. Cut a magnet in two and you won’t separate the north from the south pole. You’ll end up with two magnets, each with a north and south pole. It’s also possible to magnetize or demagnetize bodies, such as steel. Take a hammer to a steel rod and pound on it for a while and you’ll shake those tiny particles about, forcing them to align themselves with Earth’s magnetic field.

Are humans magnets? Well, I got a charge out of that question (joke). Actually that’s a wonderful question, and the answer is that we can mimic a magnet’s force by becoming "electrified." Just as a magnet can attract a magnetic material from a distance (without touching it), so too can an electrified object. Don’t ask me to explain that though, because it’s one of those incredible mysteries (invisible attractions and repulsions) that keep scientists up all night wondering about them. Meanwhile, on the next cold, dry day, rub a balloon against your body and then put it next to your hair. See if your hair doesn’t stand on end.

QUESTION:

What makes baking soda and vinegar foam up?

REPLY:

Thanks for asking, because these two products are used to make miniature volcanoes! The baking soda reacts with the vinegar, producing carbon dioxide gas. As the gas forms, it expands quickly. And what is foam but air bubbles surrounded by a veneer of matter, such as a liquid. Now, if you want to make a really neat volcano here’s what you need:

16-oz (480 ml) soda bottle, large baking pan, 2 measuring cups (250 ml), 1 tablespoon (15 ml) flour, 1 tablespoon (15ml) baking soda, spoon, small funnel, red food coloring, 1 cup (250ml) white vinegar, tap water, some newspaper.

Here’s what you do:

1. Spread out the newspaper to cover your work area.
2. Place the soda bottle in the pan.
3. In one of the measuring cups, mix the flour and baking soda.
4. Pour the flour and baking soda mixture through the funnel into the soda bottle.
5. Add 20 drops of red food coloring to the flour mixture in the bottle
6. Pour about 1/2 of the vinegar into the bottle, and
7. watch the foaming begin!

When the foaming stops, pour the remaining vinegar into the bottle. Have fun!

QUESTION:

I read about the aurora lights being seen from Washington now (March 2000). The newspaper said that this occurs every 11 years. Why don’t we see it for the rest of the years?

REPLY:

Well, if that’s what the newspaper said, it’s wrong. The Sun’s sunspot cycle is about 11 years. Sometime this year we should reach what is called sunspot maximum. During this time the Sun is extremely active, so active that sometimes it can shoot out energetic solar flares whose radiation reaches Earth to cause large auroras. These auroras can be seen from mid-latitudes in the United States and even some southern states. But the aurora happens all year long, every year, if you live in Canada and Alaska.

So, what the newspaper really meant to say is that solar activity will be reaching a maximum sometime soon (if it already hasn’t), and the possibility of seeing an aurora over Washington now is pretty good.

QUESTION:

I am an 8^th grader at the Kansas School for the Deaf. I am researching "ultraviolet rays: good and bad effects." I can find bad effects, but cannot find information about good effects. Can you help me?

REPLY:

Wow, fantastic question. We hear so much about the Bad UV. That’s because we’re fragile creatures when it comes to the power of the universe. But ultraviolet light is a part of the Sun’s radiant energy. It is a part of the visible spectrum. And it is as important as visible light. It is much like visible light except that it is of higher energy. All life on Earth – human, plant, and animal – depends on the Sun. The sun’s energy gives us heat, light, and ultraviolet (UV) rays. We can feel heat and see the light . . . but we can’t see or feel UV rays. Our eyes can’t see ultraviolet light, but that doesn’t mean it’s not important.

Did you you know that bees see in ultraviolet light? That’s right, when a bee looks for nectar, it seeks flowers that have certain lines on them – lines that we cannot see – that lead to the center of the flower. Following these lines like a plane follows landing lights at an airport, the bee goes straight to the nectar, pollinating the flower along the way. Now that’s a positive side to UV light!

Ultraviolet light also alters the genetic (DNA) material in cells, so that bacteria, viruses, molds, algae and other microorganisms can no longer reproduce. Some companies, like Ultraviolet Technologies, use UV light to purify drinking water. Used properly, ultraviolet light effectively destroys bacteria, viruses and other microorganisms in water and wastewater, without using chemicals. By doing away with chemical treatment, many other problems are also eliminated.

But here’s the most important aspect of UV light. As you may know, it is the ozone in the Earth’s atmosphere that absorbs much of the Sun’s ultraviolet radiation. So it is the ozone that protects us from dosages of this radiation that would otherwise be lethal to us today. BUT, the ozone layer was not present in Earth’s early atmosphere. And the intense ultraviolet radiation reaching Earth’s surface may have been instrumental in sparking the early chemical events that led to Earth’s original primitive life forms . . . long before you or I were around. So, in a long stretch of thinking, you can thank good old UV radiation for your life. But please do use sun block when you go to the beach 🙂

QUESTION:

Which came first, the Sun or the Earth, and how can this be proven?

REPLY:

This one’s no easier than the chicken and egg thing, I can tell you that. The answer is that the Sun probably came first. Then again, they might have formed simultaneously. We’re not absolutely certain.

For more than two centuries all our thinking about how the Solar System formed was based entirely on theory. The theory was that the Sun and planets were born from a rotating disk of cosmic gas and dust. This disk was called the solar nebula, and it is in this solar nebula that matter condensed to form the Sun and planets. What started this gravitational process of collapse is not known.

But evidence is growing to validate the theory, namely the discovery of disks of gas and dust around other stars. The Hubble Space Telescope has now resolved several dozen disks in the Orion Nebula alone, for example. Astronomers are calling these "protoplanetary" disks, and they can be seen in silhouette against the nebula’s bright background of hot gases. These disks contain more than enough gas and dust to provide the raw materials for future planetary systems. So the earliest theories seem right about the process, anyway. So, in a sense we first have a protosun forming with protoplanets. Does the protosun become a Sun before the protoplanets become planets? I don’t know.

QUESTION:

On September 14, 1999, I observed a cool grouping of clouds. But as I watched (it was afternoon), I spotted a faint high object. At first I thought it was just a plane, but it slowed, then for less than half a second it went the opposite way it was going originally. Then it slowed and went back on its original course, to the south. During the time I saw it, it was amongst the high cloud formation. My mother suggested that it might be a balloon. But at some point an identical object appeared for less than a second, moving parallel with the first object, then disappeared. Then about a second or two later, the first object faded out. What do you think it was?

REPLY:

Anyway, first of all, I admire you going out to look at the clouds. What a wonderful, rewarding, and almost forgotten, pastime. Naturally, I am an avid skywatcher too. Which brings us to your sighting. I actually don’t have much to go on, since you didn’t mention any color (or lack of color) or size. But the behavior seems to be avian to me – *very* high hawks or raptors, especially now during the seasonal migrations, and especially since you obviously saw a pair of objects. These birds can get quite high, so that they shimmer only faintly with the unaided eye or binoculars. Also, if the sunlight catches their feathers just right, the birds can flare into prominence as they glide, or they fade out of view, all depending on their orientation to your line of sight. The behavior you describe also sounds like a raptor’s telltale circle during a possible hunt.

QUESTION:

Is your sense of taste effected by your sense of smell? If so, why?

REPLY:

First, consider this fact, we can taste only four flavors: sweet, sour, salt, and bitter. All other "flavors" are really "smells." To smell something, there must be microscopic particles released into the air and 40 nerve endings have to be stimulated in our nose. Not everything has a smell (like glass and rocks at room temperature). Now, much of our taste for food comes from smell. In fact, before we can taste anything, the substance has to be dissolved in a liquid. When you taste candy, it’s because the substance is dissolved in the saliva in your mouth. So as we chomp on a candy bar, we first dissolve it in our mouths, the particles become airborne, and as we exhale, our nose picks up the scent and our nerve endings there become stimulated. In her book, The Natural History of the Senses, Dianne Ackerman describes the phenomenon this way: "If we have a mouthful of something delicious, which we want to savor and contemplate, we exhale; this drives the air in our mouths across our olfactory receptors, so we can smell better." So isn’t it great that the nose is conveniently placed just above the mouth? Finally, try this: take a sip of milk and try to determine when you taste the milk and when you smell it. Now, block your nose and have a drink. Can you taste the milk?

QUESTION:

If you were traveling at the speed of light in a car and turn on the headlights, does anything happen?

REPLY:

Ah, yes. But first I must remind you that it’s impossible for you to travel at the speed of light, Maybe 99.99999999 . . . percent of it but not at the speed of light.

With that said, your answer can be found in Einstein’s Special Theory of Relativity, which says that the velocity of light is always constant relative to the observer. That’s it in a nutshell. As far as you (the driver of the car) are concerned, when you turn the lights on, you will see the photons from the headlights go streaming out at 186,000 miles per second. That’s your perception.

Now let me ask you this. If you are in a spaceship traveling at 100,000 miles per second and someone suddenly fires a laser at you (the laser beam travels at the speed of light), how fast does the laser light beam seem to be traveling?

Give up? Well, in traditional Newtonian physics, you would expect to see the beam travel at 186,000 – 100,000 = 86,000 miles per second. But that is not what we observe. Again, the Special Theory of Relativity says the velocity of light is always constant relative to the observer, so even though you are retreating from the laser beam you see it coming at you at the speed of light, or 186,000 miles per second.

Of course, since I still drive a cylinder 1988 Honda Civic, I don’t have to worry about such speed problems.

QUESTION:

I’ve seen pictures that have very curved lines that are said in the caption to be the trails that other particles leave when they collide with neutrinos. I’m not sure if I’m right about that, but you may know what kind of photos I mean.

What makes particles spin in such tight curves that sometimes even spiral down to a point? What are the physics involved that would make a particle travel in that manner, one would think that they would just leave in a straight line.

REPLY:

Yes. I’m familiar with the diagrams to which you refer. These are actual – though color-enhanced – images of elementary particles colliding during experiments using the monster machines called particle accelerators. These machines shoot beams of atomic particles – like a proton and a neutrino – in such a way that they collide head on at nearly the speed of light. They result is that they burst into a shower of smaller subatomic particles. Researchers use these experiments to learn more about the nature of matter and energy.

In the simplest terms (actually there is no simple way to explain sub-atomic nuclear physics in a few sentences) the wild motions of the trails you see reveal the nature of the particles, which have (or do not have) electric charge, as well as spin, and decay. So, you’re seeing the effects of attraction, repulsion, spin, and the decay of these elementary particles, as well as the transformation of some particles into smaller particles. Imagine two spinning baseballs colliding at nearly the speed of light, will even the big particles thrown off by the destruction travel in straight lines?

Thanks for the great questions.

Steve O’Meara

Remember, send your questions to ODYSSEY’s Ask a Scientist!