What causes a star to shine?

A star's color depends on...

A large sphere of hydrogen gas hot enough for nuclear reactions to occur in its core

What unit of distance is used to measure very far objects in the universe (outside of our solar system)?

What is the hottest stars' color?

Galaxies that are shaped like basketballs or footballs that have little gas and dust and are made of older, redder stars are called

What is the coolest stars' color?

Huge collections of stars, gas, and dust are called

Two stars orbiting each other's center of mass is called a

Gases shaped like disks and that have a combination of younger and older stars are called

About how long will the Sun continue to shine?

Galaxies that have large amounts of gas and dust and therefore younger stars are called

What is NOT true about the universe?

What is the correct order, from smallest to largest?

Most of the mass in the universe is thought to be

We live in the ___ galaxy.