Cypress College ASTR 116 Homework
Astronomy 116, Homework CHAPTER 17 (A) Cosmology and the Big Bang.
Due:
Print Last, First Name and date on the small Scantron in INK. Print
your last name in BIG BLOCK letters on the back of the Scantron.
Use a No. 2 pencil to fill out Scantron. Read the chapter.
Look at the videos and simulations in the CD-ROM. Answer all True/False and
Fill in the Blank questions. Then answer the following questions and
turn in your Scantron only. Choose the best answer.
1. According to the COBE satellite, the temperature of the universe is
- a) 2.7 K
- b) 3.7 K
- c) 12.3 K
- d) 19.7 K
2. Based on the abundance of deuterium, what is the maximum value of the
cosmic density compared to the critical density, if dark matter is ignored?
- a) 3%
- b) 8%
- c) 50%
- d) 120%
3. The Hubble constant suggests which of the following ages for the universe?
- a) 1 to 5 billion years.
- b) 10 to 20 billion years.
- c) At least 50 billion years.
- d) The universe is eternal; it has always existed.
4. What is the meaning of isotropic?
- a) The same in all directions.
- b) The same everywhere in space.
- c) The same temperature everywhere.
- d) The same at all times.
5. Homogeneity and isotropy, taken as assumptions regarding the structure
and evolution of the universe, are known as:
- a) The Hubble Law.
- b) Riemannian geometry.
- c) Grand Unified Theory.
- d) The cosmological principle.
6. The universe has three possible futures. Which one is correct
depends only on the average density of matter in the universe. Why
is this?
- a) The density of matter determines the strength of gravity, which
decelerates the expansion over time.
- b) The density of matter determines the rate of formation of black
holes which will eventually collapse the universe.
- c) The density of matter tells astronomers whether new matter is
constantly forming, thereby producing a steady-state.
- d) If the density is sufficiently high, the geometry of space may
be curved.
7. What is the meaning of a "closed" universe?
- a) The universe will expand forever.
- b) The universe will someday stop expanding and start to collapse.
- c) The universe will stop expanding in an infinite amount of time.
- d) The universe is in a steady-state.
8. The geometry of a closed universe, in two dimensions, resembles one
of the following.
- a) A flat piece of paper.
- b) The surface of a saddle.
- c) The surface of a cylinder.
- d) The surface of a sphere.
9. The redshift of galaxies in the universe is correctly interpreted as:
- a) A Doppler shift due to the motions of the galaxies through space.
- b) An "aging" of the light.
- c) Space itself is expanding with time; the wavelengths of photon
are stretched while they travel through space.
- d) The difference in temperatures of distant and nearby galaxies.
10. How hot was the universe at time zero?
- a) 60,000 K.
- b) 1,000,000 K.
- c) 10,000 K.
- d) We do not know.
11. If the universe is infinite in size and eternal in time, then
the sky at night should be
12. The universe right now is
- a. expanding
- b. contracting
13. As the universe expands, galaxies
- a. tend to get larger
- b. tend to get smaller
- c. are not affected by expansion, so they remain the same
size
14. Evidence for the big bang theory includes
- a. the sky is dark at night
- b. the universe is expanding
- c. the universe is 3/4 hydrogen and 1/4 helium
- d. the cosmic microwave background radiation
- e. all of the above.
15. Observations and theory imply that the universe is probably