A galaxy, which is a space filled with stars, nebulae, and other matter, can be several thousand light-abytes in size, and contain hundreds of millions of stars. The most common galaxy in our solar system is the Milky Way. The Milky Way is estimated to be around 100,000 light years in diameter, which makes it the largest known galaxy. If you were to travel to the edge of the Milky Way and look at it from that angle, you would see that it’s actually a flat plane, because it’s so far away.
The other major type of large galaxy are prot galaxies, which have irregular shells of gas and stars, and can be thought of as “proto-galaxy” because they have been around longer than the Milky Way. A few example of prot galaxies include the Virgo, which is about 7 times as old as the Milky Way, and is not bound by gravity like the Milky Way. It has a very high mass and contains a very great deal of stars, unlike the Virgo which holds only about one percent of its total star-mass together. Another example is the Teapot Galaxy, which is not bound by gravity and is about twice as big as the Virgo.
There are a number of ways astronomers think the universe is made of space, including several theories that don’t have any evidence to back them up. One theory is that everything in the universe is made up of dark matter, which has yet to be found. Another is that the universe contains “psuedospheres”, which are vacuum environments similar to what happens in our sun, but without the stars overhead. Finally, there is something called “cosmos” that is similar to the universe in that it consists of nothing but space, which is moving and stretching. Astronomers believe that this is what is causing the Grand Canyon and other great things in the sky.