What is a star?

        Take a look at the night-time sky and you’ll see more

stars than you could ever begin to count. They are

different sizes, ages, colors, and distances from Earth.

       How the Sun Stacks Up as a Star

       The Sun is a star. Stars, including the Sun,

are gigantic balls of very hot gases that give off

electromagnetic radiation. As stars go, the Sun

is not unusual at all. It is of medium size. Stars

known as giants may be 8 to 100 times as large

as the Sun. Supergiants are even larger. They may

be up to 300 times as large as the Sun. Other stars

are much smaller—only about the size of Earth.

Compared to the Earth, though, the Sun is huge.

If you think of the Sun as a gumball machine and

the Earth as a gumball, it would take a million

Earth gumballs to fill the Sun gumball machine.

       The Sun gives off enormous amounts of thermal

energy and light energy. These energies come from

powerful reactions involving the Sun’s two main

components, hydrogen and helium gas. Deep

inside the core of the Sun, the nuclei of hydrogen

atoms have such a high temperature and kinetic

energy that when they collide, they fuse together.

The nuclei combine to form a new nucleus and

a new element, helium. Huge amounts of energy

are released as this happens, which is what makes

the Sun shine.

There can be many different sizes and colors of stars