Choose the best answer to each of the following. Explain your reasoning with one or more complete sentences.
What is the shape of the Milky Way’s halo?
(a) round like a ball
(b) flat like a disk
(c) flat like a disk but with a hole in the center

Decide whether the statement makes sense (or is clearly true) or does not make sense (or is clearly false). Explain clearly.
The star–gas–star cycle will keep the Milky Way looking just as bright in 100 billion years as it looks now.

Decide whether the statement makes sense (or is clearly true) or does not make sense (or is clearly false). Explain clearly.
If we could watch a time-lapse movie of a spiral galaxy over millions of years, we’d see many stars being born and dying within the spiral arms.

Decide whether the statement makes sense (or is clearly true) or does not make sense (or is clearly false). Explain clearly.
We know that a black hole lies at our galaxy’s center because numerous stars near it have vanished over the past several years, telling us that they’ve been sucked in.

Decide whether the statement makes sense (or is clearly true) or does not make sense (or is clearly false). Explain clearly.
The Sun’s velocity around the Milky Way tells us that most of our galaxy’s dark matter lies near the center of the galactic disk.

Decide whether the statement makes sense (or is clearly true) or does not make sense (or is clearly false). Explain clearly.
The carbon in my diamond ring was once part of interstellar dust grains.

Decide whether the statement makes sense (or is clearly true) or does not make sense (or is clearly false). Explain clearly.
Many spectacular ionization nebulae are seen throughout the Milky Way’s halo.

Decide whether the statement makes sense (or is clearly true) or does not make sense (or is clearly false). Explain clearly.
If I could see infrared light, the galactic center would look much more impressive.

Use the following questions to check your understanding of what the images show and what we can learn by comparing them.
The image of X-ray emission uses different colors to represent different levels of brightness. The dark blue color represents the least bright X-ray emission. Which color represents the brightest X-ray emission?

. What are the Large and Small Magellanic Clouds, and the Sagittarius and Canis Major Dwarfs?

Decide whether the statement makes sense (or is clearly true) or does not make sense (or is clearly false). Explain clearly.
Planets like Earth probably didn’t form around the very first stars because there were so few heavy elements back then.

Decide whether the statement makes sense (or is clearly true) or does not make sense (or is clearly false). Explain clearly.
We did not understand the true size and shape of our galaxy until NASA launched satellites into the galactic halo, enabling us to see what the Milky Way looks like from the outside.

What is Sgr A*? What evidence suggests that it contains a massive black hole?

What evidence suggests that the Milky Way formed from the merger of smaller protogalactic clouds?