CHAP 25,26,27 ASTRO

Which type of galaxy is observed to contain mostly older stars?

elliptical

Edwin Hubble was able to show that (with the exception of our nearest neighbors) the farther a galaxy is from us, the

faster its moving away from us

What method would astronomers use to find the distance to a remote quasar?

finding the redshift and using Hubble's Law

When quasars "shine" (in visible light and other kinds of radiation) with a lot of energy, where (what location) does this huge amount of energy come from?

from an accretion disk around a supermassive black hole

Where would you look for the youngest stars in the Milky Way Galaxy?

in the disc

The Tully-Fisher method for measuring the distance to galaxies relies on the observed relationship between the luminosity of a spiral galaxy and

its rotational velocity (as determined from the width of the 21-cm line)

How are galaxies and quasars related?

quasars are active supermassive black holes at the centers of galaxies

Which of the following is NOT part of the growing chain of evidence that makes many astronomers suspect there is a black hole at the very center of the Milky Way Galaxy?

the Hubble Space Telescope has shown us a visible-light image of an accretion disk at the center of the Galaxy

Astronomers believe that the center of our Galaxy has a black hole with enough mass inside to make almost 4 million Suns! How do astronomers think a black hole could acquire so much mass?

the center of our Galaxy is a much more crowded region than where the Sun is found; we still see material falling toward the center and material has fallen in for billions of years

If quasars often resemble little blue stars, what was it about them that so surprised astronomers when they were discovered?

their spectral lines were at first hard to recognize and then turned out to have large redshifts

Recently, astronomers have observed stars and other objects that orbit the center of the Milky Way Galaxy farther out than our Sun, but move around faster than we do. How do astronomers think such an observation can be explained?

there must be a great deal of invisible dark matter outside the orbit of the Sun whose gravitational pull explains the faster motions we see out there

10. All active galaxies are far away.

FALSE

6. Most galaxies are spirals.

FALSE

7. Elliptical galaxies evolve into spirals.

FALSE

8. Galaxy collisions can occur, but they are extremely rare.

FALSE

Dark matter is now known to be due to large numbers of black holes.

FALSE

Globular clusters trace out the large-scale structure of the Galactic disk.

FALSE

Most ellipticals contain only young stars.

FALSE

11. Quasar luminosities are so large that astronomers have no idea what process can account for them.

TRUE

12. Astronomers have observational evidence that quasars are found in the hearts of young galaxies.

TRUE

Most of the mass of our Galaxy exists in the form of dark matter.

TRUE

The Galactic halo contains only old stars.

TRUE

nearby active galaxies are most likely the result of galaxy interactions.

TRUE

Which of the following statements about the different types (shapes) of galaxies is correct?

collisions and mergers between galaxies can sometimes change a galaxy's type (shape)