Chapter19 Review

What is the approximate diameter of the disk of the Milky Way?

• 100 light-years

• 10,000 light-years

• 100,000 light-years

• 1,000,000 light-years

• 1000 light-years

The thickness of the disk of the Milky Way is about ________ the diameter of the disk

• 1/100th of

• 1/10th of

• 1/1,000,000th of

• the same as

Approximately how far is the Sun from the center of the galaxy?

• 270 light-years

• 2700 the same as light-years

• 27 light-years

• 27 million light-years

• 27,000 light-years

Which of the following are typically found in the halo of our galaxy?

• globular star clusters

• open star clusters

• cold gas and dust

• stars of spectral types O and B

• All the other answers are correct

Which of the following typically orbit within the disk of our galaxy?

• globular star clusters

• other galaxies

• stars of spectral types O and B

• the Large and Small Magellanic Clouds

Which of the following represent the oldest stars of the Milky Way?

• O stars

• red giant stars in spiral arms

• Cepheid variable stars

• stars in globular clusters

• the Sun and other stars with similar mass

How did Harlow Shapley conclude that the Sun was not in the center of the Milky Way Galaxy?        7) _______

• by looking at other nearby spiral galaxies

• by mapping the distribution of gas clouds in the spiral arms

• by looking at the shape of the "milky band" across the sky

• by mapping the distribution of globular clusters in the galaxy

• by mapping the distribution of stars in the galaxy

Why can't we see the center of our galaxy with our eyes?

• Interstellar dust and gas absorbs and scatters visible light before it can reach us from the center.

• Stars are too densely spaced in the plane of our galaxy to see all the way to the center

• We are in the center of the Milky Way

• The center of the Milky Way does not emit enough visible light.

• There are no stars in the center of the Milky Way, just a supermassive black hole.

Approximately how long does it take stars in our region of the Milky Way to complete an orbit around the center of the Milky Way Galaxy?

• 200,000 years

• 200 million years

• 20,000 years

• 2 million years

• 2 billion years

Which of the following best describes the orbits of stars in the halo?           

• Halo stars have orbits confined to a relatively thin plane.

• Halo stars have elliptical orbits, with random orientations.

• Halo stars orbit the centers of their globular clusters, but do not orbit the center of the galaxy.

• Halo stars orbit the centers of their globular clusters, but do not orbit the center of the galaxy.

• Halo stars have elliptical orbits, but all orbiting in the same direction.