1.	The question asked in Olber's paradox of cosmology is A. "Why is the sky dark at night?" B. "How old is the universe?" C. "What is beyond the edge of the universe?" D. "Where did the universe come from?"

2.

Newton reached the conclusion that the universe must consist of an infinite expanse of stars because A. he was unable to detect the movement of stars around a common center, which his theory required for stability against collapse in a finite universe. B. he reasoned that a finite number of stars would eventually fall together under their mutual gravity. C. of his religious conviction that the creator would create nothing less than an infinite universe. D. he and his colleagues had observed the uniform distribution of stars all over the sky.

3.

The Hubble distance-velocity relationship states that A. all galaxies are being pulled toward a central gravitational attractor in the universe, the closest ones to the center traveling fastest. B. the farther away a galaxy is from the Local Group of galaxies, the faster it is traveling toward this group. C. the farther a galaxy is from our galaxy, the faster it appears to be traveling away from it. D. all galaxies are being repelled by the pressure from the very hot central "engine" of the universe, the ones closest to the center traveling fastest.

4.

What is the "cosmological redshift"? A. the stretching of wavelengths of photons by the Doppler shift, because they are emitted by galaxies that are moving away from us B. the loss of energy of photons as they interact with virtual particles in the vacuum, so that their wavelengths gradually increase as they travel toward us through space C. the stretching of the wavelengths of photons as they travel through expanding space D. the stretching of the wavelengths of photons as they pass through absorbing matter in galaxies between us and the emitting galaxy

5.

Why is the universe expanding? A. It is not expanding—it is our local space that is getting smaller as we fall into a supermassive black hole, making the universe seem bigger and bigger. B. because space itself is expanding, carrying the galaxies (or superclusters of galaxies) with it C. because an infinitely small but infinitely dense clump of matter exploded, sending the galaxies (or superclusters of galaxies) hurtling out through space D. because the energy from all the stars is heating the universe, making it expand like a gas that is heated

6.

What is it that keeps localized regions of space, such as things upon Earth, planetary systems, star clusters, and whole galaxies, from participating in the general expansion of the universe? A. their locations in places where irregularities in the chaotic Big Bang explosion permitted matter to condense B. the mutual gravity between objects in these systems C. the powerful and all-pervading gravity from the central supermassive black holes of galaxies, which holds everything in place within the galaxies D. the centrifugal force produced by their motion around a massive central object (e.g., the Sun, supermassive black holes, etc.)

7.

Which one of the following statements represents a correct description of the expansion of the universe? A. Space is a vacuum, but the vacuum has real properties. As galaxies (or superclusters of galaxies) hurtle outward, the expansion is gradually slowing down by the resistance of space to the passage of the galaxies. B. Space is static, but exerts an outward pressure on the galaxies in it. This pressure is accelerating the galaxies (or superclusters of galaxies) outward through space and away from each other. C. Space has a separate existence, with the galaxies inside it. As space expands, the galaxies (or superclusters of galaxies) are carried along by the expansion. D. Space is a vacuum, which is really nothing at all. The galaxies (or superclusters of galaxies) are hurtling outward through this nothingness.

8.

In relation to the universe, what does the word "isotropic" mean? A. The expansion is the same in all directions. B. The speed of expansion is the same at all distances. C. The speed of expansion at any given distance is the same at all times. D. The universe is the same everywhere, neither expanding nor contracting.

9.

The resolution of Olber's paradox (i.e., the reason why the sky is dark at night) is that A. we cannot see those stars that are farther away from us than the distance that light has traveled since the beginning of the universe. B. matter cannot have traveled farther than light has traveled during the age of the universe, so there ARE NO stars beyond a certain distance from us. C. the light from very distant stars is bent out of our line of sight by the gravitational fields of nearby galaxies. D. the light from stars beyond a certain, very large distance is completely absorbed by matter between us and the star.

10.

For any object moving uniformly, velocity = distance/time. If so, in the Hubble relationship for the expansion of the universe, V= H0d, what is the significance of the constant 1/H0? A. It is the inverse of the velocity that the object would have at a standard distance of 10 parsecs. B. It represents the average spacing between objects in the universe at the present time. C. It is merely a constant of proportionality, to allow for the different units of V and d. D. It represents the time since the expansion began, or the age of the universe.

11.

What is the "cosmic particle horizon"? A. It is the maximum distance to which our own radio and television signals will have traveled through the universe since radio was invented. B. It is the distance from which light can travel to us over the finite age of the universe, representing a viewing distance limit for us upon Earth. C. It is the distance beyond which we cannot see because of absorbing matter in the universe. D. It is the distance at which (because we see back in time as we look out into space) galaxies are just being formed.

12.

Good evidence for an original big bang, which "created" our universe, comes from A. the very high flux of 21-cm radio energy, coming from the atomic hydrogen atoms produced in the explosion. B. the rapid motions of some nearby stars, such as Barnard's Star. C. the amount of gas and dust in the solar neighborhood. D. a background "glow" of microwaves, with blackbody temperature of about 3 K.

13.	The cosmic background radiation left over after the Big Bang of the universe and pervading all observable space has an effective blackbody temperature of approximately A. 273 K B. 10 K C. 3 K D. 0 K

14.

The effect that makes the cosmic microwave background appear slightly warmer in one direction and cooler in the opposite direction is A. the focusing effect of the gravitational field of the local galaxy upon the radiation. B. the presence of many extra sources of the radiation in one direction. C. a basic asymmetry in the background radiation, related to its origin. D. the Doppler shift, caused by motion of our galaxy through space toward the constellation Leo.

15.

Even though the number of cosmic microwave background photons outnumbers hydrogen atoms by about 500,000,000 to 1 in our universe, this universe is still considered to be matter-dominated. This is because A. the photons, while collectively carrying a large amount of energy, do not carry an equivalent amount of momentum and hence play little role in collisions with matter. B. the photon energies are extremely small. C. the photons have no rest mass and hence can generate no gravity. D. the nature of these photons is such that they interact with nothing as they pass through the universe.

16.

Which of the following statements correctly describes the universe for the entire first 300,000 years of its life? A. All of the fundamental forces were united into one force. B. It was filled with free quarks (not confined inside neutrons or protons). C. It was a sea of nuclear reactions occurring at a gradually decreasing rate. D. It was opaque.

17.

What condition is necessary for the universe to be unbounded (infinite in extent)? A. The density of the universe must be equal to or less than some critical value. B. The density of the universe must be equal to or greater than some critical value. C. The universe must have no mass in it. D. The density of the universe must be exactly equal to some critical value.

18.

What will happen if the universe is unbounded? A. The universe will expand forever. B. The universe will expand to some maximum size and then fragment into mini-universes. C. The universe will reach a maximum size and stay there, like a balloon that has been inflated. D. The universe will eventually fall back in on itself, heading toward a "Big Crunch."

19.	What kind of curvature (geometry of space) does the universe have if the universe is just bounded (density = critical density)? A. flat B. parabolic C. spherical D. hyperbolic

20.	What kind of curvature (geometry of space) does the universe have if the universe is unbounded (density < critical density)? A. flat B. parabolic C. hyperbolic D. spherical

21.

If space has a hyperbolic geometry (unbounded universe), what will happen to two initially parallel flashlight beams as they traverse billions of light years of space? A. They will remain parallel. B. They will gradually diverge (move apart) to a maximum separation, and then gradually converge and cross. C. They will gradually converge (move together) and eventually cross. D. They will gradually diverge (move apart).

22.

Einstein introduced a "cosmological constant" into his formulation of the structure of the universe on the basis of the General Theory of Relativity. How did he envision that this cosmological constant would manifest itself? A. as antimatter which, by annihilating with real matter, would translate matter into energy, thereby maintaining a constant mass density in an condensing universe B. as many "white holes" which would contribute matter to an expanding universe to maintain constant density, as required by the Cosmological Principle—a continuous creation universe C. as a form of energy which, on its own, would make the universe expand—a form of antigravity D. as an extra "gravity" which would hold the universe against continuous expansion

23.

What method is being used to discover whether we live in an unbounded universe, in which expansion will continue forever, or a bounded universe, in which expansion will eventually turn into contraction and lead us to the Big Crunch? A. careful monitoring of the Moon-Earth distance to detect slow-down of the expansion of the universe B. measurement of the deviation from uniformity of the cosmic background radiation C. measurement of the curvature of the Hubble relationship, v = H0r, at large distances D. measurement of the bending of light by distant galaxies as it follows the curvature of space

24.

If space is spherical, what is the future of the universe? A. It will expand forever, not stopping even after infinite time. B. It will expand forever, but its rate of expansion slows so that it reaches zero expansion speed after infinite time. C. The future of the universe is not related to the geometry of space. D. It will expand to a maximum size and then collapse into a Big Crunch.

25.

Recent results from very bright supernovae in very distant galaxies seem to indicate that the expansion of the universe A. is continuing at a constant rate and has done so since just after the Big Bang. B. has now stopped and the universe will shortly begin to contract again toward a Big Crunch. C. is accelerating (speeding up). D. is decelerating (slowing down).

26.

In cosmology, what is the "inflationary epoch"? A. the period of universal expansion from the Big Bang to the present B. a period when the cost of living rose faster than astronomers' salaries C. the first 300,000 years of the life of the universe, when matter and radiation interacted vigorously D. a short period of extremely rapid expansion when the universe was very young

27.

Particle-antiparticle pairs are coming into existence all the time in the space around (and inside!) us. According to Heisenberg's uncertainty principle, A. the more massive the particles, the shorter the time that they can exist. B. the more massive the particles, the less precisely we know their position. C. the more massive the particles, the longer the time that they can exist. D. the more massive the particles, the more precisely we know their position.

28.

Why is it that we find no free (unbound) neutrons floating around in the universe today, whereas free protons and electrons exist in profusion? A. Free neutrons decay radioactively in about 10 minutes to produce protons, electrons and neutrinos. B. The free neutrons interact quickly with the free electrons to produce antiprotons, so there are few neutrons left. C. The original Big Bang produced only charged particles, hence neutrons were not produced and those that now exist in nuclei of atoms have come from proton decay. D. Free neutrons react readily with free protons to produce high-energy photons, or g radiation.

29.

What is the deuterium bottleneck? A. Deuterium had to form before helium could form, but deuterium is easily destroyed—thus preventing the formation of helium. B. Deuterium absorbs neutrons efficiently, thus producing heavier and heavier isotopes of hydrogen instead of heavier elements such as helium. C. Deuterium had to form before helium could form, but deuterium is almost impossible to create—thus preventing the formation of helium. D. Helium is used up in the formation of deuterium. However, deuterium is difficult to create, thus leaving us with large amounts of helium.

30.	Which elements were created during the Big Bang? A. hydrogen, helium, and lithium B. hydrogen, helium, lithium, and beryllium C. hydrogen and helium D. only hydrogen

31.

At what speed will the neutrino travel if it is shown to have a small mass? A. Because it will be a particle with mass, its speed will be governed by the temperature of its surroundings because it will always be in thermal equilibrium. B. less than the speed of light, c C. faster than the speed of light, because this is the only way that it can have mass D. Because of its nature, it can only exist when it is traveling at the speed of light, just like photons of electromagnetic radiation.

32.

How do we know that matter in the early universe was extremely smooth (i.e., not really lumpy)? A. because the cosmic background radiation is almost completely isotropic B. because at the present time galaxies are spread almost completely uniformly through the universe C. because quasars are spread almost completely uniformly around the sky D. because the expansion of the universe is almost completely isotropic

33.	How many fundamental forces are known in science? A. five B. three C. four D. six

34.	What is the range of the gravitational force (the maximum distance over which it acts)? A. 1026 m, or roughly the distance to the farthest quasars B. infinity C. 1013 m, or roughly the size of the solar system D. 1021 m, or roughly the size of the Milky Way Galaxy

35.	If gravity holds galaxies together and the electromagnetic force holds atoms together, what does the weak nuclear force hold together? A. nuclei B. nothing C. the quarks inside protons and neutrons D. leptons (particles including electrons and neutrinos)

36.	The weak force A. acted only during the Big Bang, and has no known role in the universe at the present time. B. holds the quarks together inside a proton or neutron. C. acts during certain kinds of radioactive decay. D. attracts the electrons to the nucleus, holding the atom together.

37.	The physical force that controls the structure of the nucleus and binds together protons and neutrons is the A. gravitational force. B. electromagnetic force. C. strong nuclear force. D. weak nuclear force.

38.	What are quarks? A. the component particles making up protons and neutrons B. antielectrons (the antimatter form of electrons) C. particles of zero electric charge and zero mass that are emitted by nuclear reactions in the Sun's core D. the component particles making up electrons

39.	When did the inflationary epoch begin? A. when the strong force "froze out" as a separate force B. when pair production ceased C. when gravity "froze out" as a separate force D. when the electromagnetic force "froze out" as a separate force

40.

A cosmic string is A. a temperature fluctuation in the cosmic microwave background radiation. B. a long line of galaxies on the edge of a cosmic void. C. a region of space in which the strong, weak, and electromagnetic forces are unified. D. a distortion of space connecting two quarks in a subatomic particle such as a proton, preventing the quarks from traveling freely.

41.

What recent observations seem to indicate the presence of cosmic strings in space? A. the evidence of incredible activity and energy production at the centers of galaxies B. the circular arcs of light surrounding clusters of galaxies, obvious evidence of gravitational bending of light around compact massive structures C. the straight bars across the centers of barred spiral galaxies D. the distribution of galaxies in thin sheets and walls surrounding vast voids

42.

Opposite sides of the universe have the same temperature, yet according to the standard Big Bang Theory these points are too far apart for light to have traveled from one side to the other in the age of the universe; i.e., they cannot have exchanged heat to even out their temperature. Why, then, do they have the same temperature? A. Light (and heat) could travel much faster in the early universe, allowing them to exchange heat while the universe was young. B. The expansion of the universe has always been the same everywhere; therefore all parts of the universe have the same temperature regardless of whether they have ever exchanged heat or not. C. pure coincidence D. They were originally close together and evened out their temperature, then a rapid inflation of the universe carried them far apart.

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