Multiple-Choice Questions
1) Homogeneity and isotropy, taken as assumptions regarding the structure and evolution of the universe, are known as
A) the Grand Unified Theory.
B) the cosmological principle.
C) the General Theory of Relativity.
D) the Doppler Effect.
E) Olbers' Paradox.
Page Ref: 17.1
2) The concept that the direction of observation does not matter overall is
A) relativity.
B) homogeneity.
C) universality.
D) isotropy.
E) geometry.
Page Ref: 17.1
3) The concept that on the grandest of scales, the universe is similar in appearance everywhere is
A) special relativity.
B) general relativity.
C) homogeneity.
D) isotropy.
E) universality.
Page Ref: 17.1
4) Because almost all galaxies show redshifted spectra, we know that
A) our understanding of redshift is wrong.
B) we must be at the center of the universe.
C) the universe is expanding.
D) the sky must be dark at night.
E) the Universe is closed.
Page Ref: 17.2
6) The darkness of the night sky in an infinite universe is addressed in
A) General Relativity.
B) Special Relativity.
C) Steady State Physics.
D) Olbers' Paradox.
E) the Cosmological principle.
Page Ref: 17.2
7) The redshift of the galaxies is correctly interpreted as
A) a Doppler shift due to the random motions of galaxies in space.
B) an aging of light as gravity weakens with time.
C) space itself is expanding with time, so the photons are stretched while they travel through space.
D) placing our Galaxy near the center of the Local Group.
E) the differences in temperatures and star formation in old and young galaxies.
Page Ref: 17.2
8) What does the Hubble law imply about the history of the universe?
A) The universe must be infinitely old and huge.
B) The universe had a beginning and has expanded since, giving it a finite age.
C) The Milky Way lies exactly at the center of this expansion.
D) The red shifts will lengthen with time due to dark energy.
E) The red shifts will turn to blue shifts as universe contraction follows the expansion.
Page Ref: 17.2
9) From the 1970s to the present, the accepted value of H has almost doubled, so
A) the age of the universe is twice as old as we originally believed.
B) the age of the Universe is half what we believed.
C) the Copernican principle is not valid beyond our solar system.
D) the ages of the oldest globular clusters are invalid.
E) the critical density must also be halved.
Page Ref: 17.2
10) In which of the following models will the universe stop expanding?
A) Open Universe
B) Closed Universe
C) Critical Density Universe
D) Steady State Universe
E) All have an ultimate collapse.
Page Ref: 17.3
11) With a Hubble constant of 70 km/sec/Mpc, the critical density would be
A) 1.4 g/cc.
B) 4 × 10-36 g/cc.
C) 9 × 10-27 kg/m3
D) 6.23 × 10-23 g/mole.
E) 3 × 10-31 g/cc.
Page Ref: 17.3
13) The presently accepted value of the Hubble constant gives an age of
A) 4.5 billion years.
B) 8-9 billion years.
C) 14 billion years.
D) 18 billion years.
E) 22 billion years.
Page Ref: 17.3
14) What is the meaning of a "closed" universe?
A) The universe is already collapsing back into another cycle.
B) The universe will someday stop expanding and begin collapsing inward.
C) The universe will slow down and stop expanding in an infinite amount of time.
D) The universe is in a steady state, with constant replacement of matter and energy.
E) The universe will expand forever.
Page Ref: 17.3
15) In the closed universe model, the geometry of spacetime in two dimensions resembles the surface of a
A) flat piece of paper.
B) saddle.
C) cylinder.
D) sphere.
E) pyramid.
Page Ref: 17.3
16) If the density of the universe is greater than critical, then
A) there is more matter than energy.
B) the universe is closed, gravity wins, and will shrink to the Big Crunch.
C) the universe is flat, and Euclid is right.
D) the Universe will continue expanding forever.
E) the universe will end up as nothing but black holes.
Page Ref: 17.3
17) The latest studies from ________ led to the discovery of "dark energy."
A) Cepheid variables in the Virgo Cluster
B) Type II supernovae in the Large Magellanic Cloud
C) the gravitational lensing by MACHOs
D) the COBE microwave ripples
E) Type I supernovae at very large red shifts
Page Ref: 17.4
18) According to the turn-off points of the oldest globular clusters, they are about
A) 4.5 billion years old.
B) 6.8 billion years old.
C) 10 billion years old.
D) 12 billion years old.
E) 16 billion years old.
Page Ref: 17.4
19) The expansion rate of the Universe is
A) increasing.
B) decreasing.
C) constant.
D) different in different directions.
E) independent of time.
Page Ref: 17.4
20) In the critical density universe now proposed, the ratio of dark energy to matter is about
A) 1 to 100
B) 1 to 1.
C) 3 to 1
D) 10 to 1.
E) 1 to 5
Page Ref: 17.4
21) The major players in the discovery of the cosmic microwave background were at
A) Cal Tech and Mt. Palomar.
B) Jet Propulsion Lab and MIT.
C) Bell Labs and Princeton.
D) Kitt Peak and the University of Arizona.
E) Keck telescopes and the University of Hawaii.
Page Ref: 17.5
22) What temperature does COBE find the Big Bang has cooled to by now?
A) About 3,000 K
B) 5,800 K
C) About 300 K
D) Just over 2.7K
E) 1.4 K
Page Ref: 17.5
23) The discovery of the cosmic microwave background was important because
A) it established a firm center of the Universe.
B) it was was experimental verification of a prediction from the Big Bang theory.
C) it proved that astronomy at radio wavelengths was possible.
D) its detection was a major advance in microwave testing.
E) it showed the universe must be closed, with more than the critical density here.
Page Ref: 17.5
24) In comparing the energy radiated by all the stars and galaxies that ever existed with the COBE observations of the cosmic microwave background, we find
A) the stars far outshine the feeble microwaves, now so red shifted.
B) that bright and dark energy are approximately equal.
C) the cosmic microwave background is ten times greater.
D) that dark energy, like dark matter, will lead to a closed universe.
E) that matter makes up about 35% of the universe.
Page Ref: 17.5
25) Concerning dark energy, we do know
A) that it is created when matter annihilates anti-matter.
B) its density remains constant over time, so it is not important in the early Universe.
C) combined with dark matter, it will ultimately produce a closed universe.
D) that it was revealed with Type II supernovae distances in the late 1990s.
E) that it makes up 90% of all the matter and energy in the whole universe.
Page Ref: 17.5
26) What key event happened during the decoupling epoch?
A) Pairs of neutrons and protons were created.
B) Electrons and positrons were created.
C) expansion cooled the universe enough that protons could capture electrons in orbit.
D) Dark energy accelerated the cosmos on to infinity.
E) The universe underwent a brief period of very rapid expansion.
Page Ref: 17.6
27) The Big Bang formed
A) only hydrogen.
B) only helium.
C) hydrogen and helium, but nothing else.
D) all elements up to iron.
E) all elements found in nature now.
Page Ref: 17.6
28) Before the decoupling,
A) the Universe was transparent to radiation.
B) the Universe was opaque to radiation.
C) protons and electrons combined to form atoms.
D) there was more helium than hydrogen.
E) deuterium produced electrons and positrons.
Page Ref: 17.6
29) Most of the deuterium formed right after the Big Bang
A) is still around today.
B) broke down into electrons and neutrons.
C) turned into dark matter.
D) quickly burned into helium nuclei.
E) was found in the globular clusters.
Page Ref: 17.6
30) Why didn't elements heavier than helium form in the first minutes of creation?
A) The first generation of stars used them up too quickly to observe them.
B) There was not enough matter in the universe at that time.
C) When He-4 was formed, the expansion cooled the cosmos below 100 million K.
D) The electrons slowed down enough to be captured into orbits by protons.
E) Only Type I supernovae can produce iron and heavier elements.
Page Ref: 17.6
31) The 3 K background radiation represents
A) the Big Bang itself.
B) the time of decoupling.
C) the formation of the first galaxies.
D) the outer edge of the Universe.
E) formation of the first quasar.
Page Ref: 17.6
32) The best answer to both the flatness and horizon problems is
A) the Steady State Theory.
B) the GUT theory.
C) the inflationary epoch.
D) dark energy.
E) decoupling.
Page Ref: 17.7
33) In the Grand Unified Theory, the superforce was
A) only dark energy.
B) a union of the weak and electromagnetic forces.
C) a union of all matter and energy.
D) a union of the gravitational, strong and weak nuclear, and electromagnetic forces.
E) was only in effect at low energies.
Page Ref: 17.7
34) The satellite that found the ripples in the cosmic background that led to galaxies is
A) SOHO.
B) the Hubble Space Telescope.
C) the Chandra X-Ray Observatory.
D) COBE.
E) the Compton Gamma Ray Observatory.
Page Ref: 17.8
35) In 1992 COBE observations revealed
A) that the universe had less than the critical density, so was open.
B) the microwave background radiation is not isotropic, but centered on Virgo.
C) the dark matter in the universe is normal (baryonic), so the universe is closed.
D) there are small ripples in the microwave background, the seeds of galaxies.
E) the existence of dark energy.
Page Ref: 17.8
36) The tiny ripples in the background radiation COBE found are due to
A) a gravitational redshift caused by growing dark clumps.
B) different velocities of the edge of the Universe.
C) reddening by interstellar dust clouds in our galaxy.
D) variations in the speed of different wavelengths of light.
E) bubble-like nature of space.
Page Ref: 17.8