The elliptical galaxy is one of the most intriguing parts of our universe. They have the most variation in size of any type of galaxy, as they can be very large, or extremely small, with some of them being less than 10% of the size of our galaxy, the Milky Way. This is due to less gas and dust, which results in fewer stars and a smaller galaxy.
In fact, they can often be mistaken for stars due to their compact appearance. Let’s look at some more interesting facts about the Elliptical galaxy.
Elliptical Galaxy Facts
- Though we aren’t entirely sure, it’s said that elliptical galaxies may be the result of a collision between two spiral galaxies.
- Elliptical galaxies can be the biggest in our universe, which we refer to as a giant elliptical. They have over a trillion stars, and can have a diameter that is 10x our Milky Way.
- As well as being the largest, elliptical galaxies can also be the smallest galaxies in our universe too. These are called “dwarf elliptical”.
- Elliptical galaxies can have as little as ten million stars in them, or as much as one hundred trillion stars in them – they vary greatly!
- They are generally made up of a lot of older stars that have a relatively low mass.
- There is very little dust in an elliptical galaxy, which is one of the reasons why there are few younger stars.
- One of the brightest galaxies in our sky, Centaurus A, is an elliptical galaxy.
- Although it was once thought to be true, elliptical galaxies actually don’t evolve into spiral galaxies.
- All elliptical galaxies have a supermassive black hole at their center – the size of the black hole is directly related to the size of the galaxy itself.
- Whereas spiral galaxies are often found on their own, elliptical galaxies are primarily found in clusters amongst other stars.
- An elliptical galaxy is one of four different classifications that we give to galaxies, along with a classic spiral galaxy, barred spiral galaxy and an irregular galaxy too.
Elliptical Galaxy Classification
When we’re looking at an elliptical galaxy, they’re not all the same in their appearance. Some can appear as a sphere, whilst others appear as a more oval shape, or an ellipse. We classify an elliptical galaxy based on its shape, ranging from E0 to E7. So for example, an E0 elliptical is going to be almost a perfect sphere, whereas an E7 galaxy is going to be very oval shaped, like a football.
In addition to these classifications, we also have what is called an S0. This is somewhere between an elliptical galaxy and a spiral galaxy, which is why it starts with an S instead of an E. We call this a lenticular galaxy, which is based on its star formation, which is often full of rich clusters in comparison to other types of galaxy.
Common Questions about Elliptical Galaxies
What is an example of an elliptical galaxy?
There are many different examples of elliptical galaxies in our skies. One of the most well known elliptical galaxies is called Cygnus A, which was discovered back in 1939 by Grote Reber, the famous radio astronomer who helped us understand astronomy via radio frequencies.
What is the average age of an elliptical galaxy?
Elliptical galaxies are often some of the oldest galaxies in our night sky – they tend to range anywhere between 7 billion and 10 billion years old.
How many stars can an elliptical galaxy have?
There are elliptical galaxies in our universe that have trillions of stars, some of them even having more than one hundred trillion. These large elliptical galaxies are referred to as ‘giants’.
How do elliptical galaxies form?
No one is 100% sure how elliptical galaxies form. However, one of the main theories about how elliptical galaxies form is that they are actually made up of two or more spiral galaxies that have collided with each other, resulting in a elliptical. This would make sense when we’re considering how large a giant elliptical galaxy can be, as they may actually consist of several spiral galaxies combined into one.
How are elliptical and spiral galaxies different?
Elliptical galaxies aren’t just different from spiral galaxies due to their appearance. There is also differences in the composition of each type of galaxy and what they are made of. So whilst a spiral galaxy has a lot of dust and gas, an elliptical galaxy has little to none of this dust of gas visible.
All in all, the Elliptical galaxy is one of the most interesting parts of our night sky and our universe in general. We hope to learn more about the elliptical galaxy in the coming years, with more discoveries being made each year. Hopefully this has helped you learn a little about the elliptical galaxy.