Don’t peek at the answer until you’ve given this a good try! Then, scroll down a bit and the truth will be revealed to you.
Credit: NASA/CGRO/EGRET/ Dirk Petr
What in the world is it?
Four moldy donut holes? A drop of water seen under different colored lights? How about different views of a pollen polyp seen through an electron microscope?
Nope! Believe it or not, you’re looking at the planet Earth as seen through the eyes of NASA’s Compton Gamma-Ray Observatory, which was active from 1991 to 2000. This new picture is the first detailed image of our planet radiating gamma rays, a type of light that is millions to billions of times more energetic than visible light.
“If our eyes could see high-energy gamma rays, this is what the Earth would look like from space,” said Dr. Dirk Petry of NASA Goddard Space Flight Center in Greenbelt, Md. The image portrays how the Earth is constantly bombarded by particles from space.
These particles, called cosmic rays, hit our atmosphere and produce the gamma-ray light high above the Earth. The atmosphere blocks harmful cosmic rays and other high-energy radiation from reaching us on the Earth’s surface.
Petry assembled this image from seven years of data The Compton Observatory orbited the Earth at an average altitude of about 260 miles (420 km). From this distance, the Earth appears as a huge disk with an angular diameter of 140 degrees.
The long exposure and close distance enabled Petry to produce a gamma-ray image of surprisingly high detail.
“This is essentially a seven-year exposure,” Petry said.