Astronomy Exam 2 Part 5

1. We only observe events that happened in the past because

A. it takes time to analyze the data.

B. the speed of light is finite.

C. the Universe is very old.

D. our telescopes are not yet large enough.

E. the light has been red-shifted.

2. Astronomers proposed the presence of dark energy because

A. the expansion of the Universe appears to be accelerating.

B. the expansion of the Universe appears to be decelerating.

C. galaxies appear to be brighter than expected.

D. the Universe appears to become cooler.

E. the Universe appears to become hotter.

3. The cosmic microwave background radiation provides strong evidence that

A. star formation has been taking place for billions of years.

B. the Universe evolved from a hot, dense state.

C. colliding galaxies release enormous amounts of radiation.

D. at 3 Kelvin, the early Universe was extremely cool.

E. the early Universe had more stars.

4. Because the large redshifts of quasars arise from the expansion of the universe, we can conclude that

A. quasars must be very small.

B. quasars must be within the Local Group.

C. quasars must be single stars with extremely large masses.

D. quasars must be moving toward Earth with a large radial velocity.

E. quasars must be very luminous.

5. The cosmic microwave background radiation is visible in every direction because

A. we are at the center of the Universe..

B. we are looking back to when the Universe was young in every direction

C. we are looking back to when the Universe was cool.

D. it has been scattered by dust to every direction over the age of the Universe.

E. it originated in a sphere around our own Galaxy.

6. The cosmic background radiation comes from a time in the evolution of the universe

A. when protons and neutrons were first formed.

B. when electrons began to combine with nuclei to form atoms.

C. when the big bang first began to expand.

D. the inflationary period.

E. when gamma rays had enough energy to destroy nuclei.

7. Most of the carbon, nitrogen, oxygen, and other heavy elements on the Earth were originally produced in

A. the Big Bang.

B. our Sun.

C. massive stars that have evolved long ago.

D. the formation of the Earth.

E. interstellar gas clouds.

8. Reddening of starlight is caused by

A. the faint pink glow of hot interstellar gas.

B. the gravitational pull on photons leaving the star’s surface.

C. the expansion and cooling of a star’s atmosphere as it grows older.

D. scattering of blue light by interstellar dust grains.

E. the expansion of the universe.

9. The blue-shift exhibited by some nearby external galaxies lends support to the

A. Big Bang model, because those galaxies are expanding towards us.

B. Local Group concept, because nearby galaxies interact gravitationally.

C. evolution theory, because galaxies change color as they evolve.

D. oscillating Universe theory, because some galaxies are moving together already.

E. static theory, because the local Universe is apparently not expanding