Stars are all part of a huge galaxy. We live in the Milky Way galaxy. There are probably an infinite number of galaxies out there

We can only see the stars in our galaxy. Most of the stars out there are stars we cannot see. The closest star you can see during the day. The Other stars cannot be seen.

Stars are the brightest and the hottest things in the universe. The color of the star depends how hot the star is. A yellowish whitish star is about 10,000 degrees and a blue star can be as hot as 200,000,000 degrees.

The sun is not the biggest star out there. It's only huge because it is the closest star and the only star in our solar system. The sun is just an average size star. the sun is just 432,288 miles in diameter. Stars can be much bigger and much smaller.

A small, young star is called a protostar. A dead small old star is called a white dwarf. A huge star is called a super massive star. Our sun is an average sized star. It's radius is about 432,450 miles. The biggest star is 1.540 solar radii in diameter.

The sun is like a balance. Gravity pushes the star inwards and keeps the star together. The thermonuclear fusion pushes the star outwards. These act together to stabilize the star.

Our sun is mostly made out of hydrogen and helium. When the sun runs out of hydrogen, used to keep the star stable, the star becomes unstable. The star collapses becoming denser and denser and hotter and hotter until one day it becomes hot enough to fuse helium.

Once it fuses helium it the energy from the fusion is so strong that it defeats gravity and the atmosphere and the outer surface of the star gets pushed away. Our sun will do this, and will get so big that it will swallow up the 4 inner planets, including earth. The farther the atmosphere gets away from the core the less the gravity is. Eventually all that will be left in the stars control is the core.