23.18: Beyond the Solar System- Challenge 3

1. The closest galaxy to ours is the ___.

Andromeda Galaxy

2. A ___ galaxy has pinwheel-like arms and rotates around a central bulge.

spiral

3. The three types of galaxies are ___.

spiral, elliptical, and irregular

4. Our solar system is located ___.

within one of the spiral arms of the Milky Way

5. The ___ of the Milky Way contains the oldest stars.

halo

6. There is a ___ in the center of the Milky Way.

black hole

7. Redshift is ___.

the phenomenon in which absorption bands are shifted towards the red end of the spectrum

8. According to the Doppler Effect, ___.

as waves moves closer to you, the waves pack closer together, and vice versa

9. Hubble's Law states that ___.

the farther away a galaxy is, the faster it is moving away from us

10. ___ and ___ are the most abundant gases in the universe.

Hydrogen; helium

11. During the immediate aftermath of the Big Bang, hydrogen nuclei collided and fused into ___ nuclei.

helium

12. According to the Big Bang Theory, the universe formed ___ years ago.

13.7 billion