Galaxies & The Universe NOTES (Study These Term First)

What are galaxies made of?

gas, space dust, stars, star systems, planets, dark matter, and more.

What are the three types of galaxies?

Spiral, Elliptical, and Irregular

Which type of galaxy is the most common?

Spiral

Describe the shape of a spiral galaxy.

It has a halo of spiraling arms coming out of a central disk.

Where are the oldest stars in a spiral galaxy?

Older stars are towards the center of the halo.

Describe the shape of an elliptical galaxy.

It has a spherical halo with a bright central disk.

What kind of stars make up most of an elliptical galaxy.

Old, red stars.

Explain how irregular galaxies get their shape.

These galaxies get their shape by being pulled by the gravity of nearby galaxies.

Name our home galaxy.

The Milky Way

What type of galaxy is the Milky Way galaxy?

spiral galaxy

Which galaxy is closest to our home galaxy?

Andromeda Galaxy

Where do we live in the Milky Way?

We live out on one of the spiraling arms.

What will eventually happen between the Andromeda and the Milky Way galaxy.?

They will merge into a single, big elliptical galaxy.

What are Local Groups?

Groups of galaxies held near each other by gravity.

What are Superclusters?

Groups of galaxy clusters or local groups held together by gravity.

When do scientists think the Big Bang happened?

13.4-13.9 billion years ago.

How is the universe moving today?

The universe is still expanding.

What do scientists estimate makes up 90% of the matter in the universe?

Dark Matter