Unit 5: The Universe

Front

What is a galaxy?

Back

A galaxy is a large collection of stars, gas, and dust held together by gravity.

Front

What force is responsible for holding the stars, gas, and dust together in a galaxy?

Back

Gravity.

Front

What is a black hole?

Back

A black hole is an object so dense that its gravity is so strong that even light cannot escape.

Front

What color of star is the hottest?

Back

Blue.

Front

Where do all stars begin their life?

Back

In a Nebula.

Front

What does the H-R diagram compare?

Back

It compares a star's brightness to its temperature.

Front

What is the main component of a nebula?

Back

Gas and dust.

Front

What is the life cycle stage of a star after a nebula?

Back

Protostar.

Front

What is the significance of a star's color?

Back

A star's color indicates its temperature; blue stars are the hottest.

Front

What happens to a star after it exhausts its nuclear fuel?

Back

It can become a red giant or a supernova, depending on its mass.