Astronomy Exam 2 Part 4

10 Questions | By Mllanos87 | Last updated: Mar 22, 2022 | Total Attempts: 108

Questions

Settings

Create your own Quiz

Astronomy exam part 4. Taken from astron. 100 exam 2.

Questions and Answers

1.

We see distant objects as they appeared in the distant past because
- A.
  
  A. the universe is expanding.
- B.
  
  B. the fabric of space is curved by the presence of mass.
- C.
  
  C. all galaxies see themselves at the center of universal expansion.
- D.
  
  D. light travels at a finite velocity and takes time to get to us.
- E.
  
  E. the universe had a distinct beginning about 15 billion years ago.
2.

Astronomers use Cepheid variable stars to measure galaxies’ distances because
- A.
  
  A. the faster they vary, the more distant they are.
- B.
  
  B. their luminosity can be determined from their period of variation.
- C.
  
  C. they obey Hubble’s law.
- D.
  
  D. they are the most common type of main-sequence star visible in galaxies.
- E.
  
  E. they all lie in the same spot on the HR diagram.
3.

Whether the universe is open, closed or flat depends on the
- A.
  
  A. luminosity
- B.
  
  B. temperature
- C.
  
  C. radius
- D.
  
  D. rotation rate
- E.
  
  E. density
4.

Spiral galaxies are known to rotate by measuring
- A.
  
  A. the Doppler shifts of stars on each side of its center.
- B.
  
  B. the relative motions of other galaxies inside them.
- C.
  
  C. the length and curvature of their spiral arms.
- D.
  
  D. the time it takes individual stars to orbit the center.
- E.
  
  E. None of the above—galaxies don’t rotate.
5.

An astronomer now living in another galaxy far away from ours would see
- A.
  
  A. some of the most distant galaxies coming toward her and some going away from her.
- B.
  
  B. many more nearby quasars than we do.
- C.
  
  C. our Galaxy approaching her.
- D.
  
  D. the more-or-less same relation between redshift and distance that we see.
- E.
  
  E. All of the above.
6.

Edwin Hubble recognized that the Andromeda nebula was a separate ”island universe” rather than a component of our own galaxy because
- A.
  
  A. he observed that the nebula was rotating.
- B.
  
  B. he used Cepheid variables to find it was a tremendous distance away.
- C.
  
  C. he determined that the nebula was moving away from our Galaxy.
- D.
  
  D. he counted that there were more than one billion stars in the nebula.
- E.
  
  E. he detected dust and gas in the nebula.
7.

Most of the helium in the Universe is believed to be produced in
- A.
  
  A. red giants.
- B.
  
  B. main-sequence stars.
- C.
  
  C. planetary nebulae.
- D.
  
  D. the Big Bang.
- E.
  
  E. supernovae.
8.

Based on the rotation curves of stars in spiral galaxies and the Milky Way, most of the mass in galaxies is believed to be in the form of
- A.
  
  A. dark matter.
- B.
  
  B. neutral hydrogen.
- C.
  
  C. luminous stars.
- D.
  
  D. ionized hydrogen.
- E.
  
  E. black holes.
9.

What is meant by dark matter?
- A.
  
  A. Mass that disappears into black holes.
- B.
  
  B. Mass made of anti-matter whose effect cancels out the gravity of ordinary matter.
- C.
  
  C. Mass that radiates strongly at X-ray wavelengths and is therefore invisible with ordinary light.
- D.
  
  D. Mass deduced to be present from its gravitational effect but which emits no visible light or other detectable radiation
- E.
  
  E. None of the above.
10.

Hubble’s law
- A.
  
  A. tells us that the universe is expanding.
- B.
  
  B. permits us to measure the distances to distant galaxies and quasars.
- C.
  
  C. implies that the universe had a beginning about 15 billion years ago.
- D.
  
  D. says that more distant galaxies recede more rapidly than nearby ones.
- E.
  
  E. all of the above.