A) 3K
B) 300K
C) 3000K
D) The universe cannot be said to have a single temperature.
F) All of the above
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A) We look all the way to the cosmological horizon,where we can see the actual conditions that prevailed all the way back to the first instant of the Big Bang.
B) The conditions in the very early universe must have been much like those found in stars today,so we learn about them by studying stars.
C) We work backward from current conditions to calculate what temperatures and densities must have been when the observable universe was much smaller in size.
D) We can only guess at the conditions,since we have no way to calculate or observe what they were.
F) A) and C)
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B) False
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A) unify gravity with the strong and weak forces.
B) unify the electromagnetic and weak forces.
C) unify all four forces together.
D) unify the strong force with the electromagnetic and weak forces.
F) A) and B)
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A) Inflation predicts that the early universe should have regions of enhanced density that could have acted as "seeds" for the formation of galaxies and large structures.
B) The universe should be geometrically "flat" (in the four dimensions of spacetime) .
C) Inflation predicts that the temperature of the cosmic microwave background should be almost (but not exactly) the same everywhere.
D) Inflation predicts that the entire universe must be far larger than the observable universe.
F) A) and C)
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A) You are in the center of a young star.
B) You are in the early universe before the Planck time.
C) You are floating somewhere in the universe near its end,10¹⁰⁰ years from now.
D) You are inside the nucleus of an atom.
E) You are in the universe shortly after inflation.
G) B) and E)
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A) By the time stable helium nuclei had formed,the temperature and density had already dropped too low for helium fusion to occur.
B) Helium fusion occurred,but the carbon nuclei that were made were later destroyed by the intense radiation in the early universe.
C) Temperatures in the early universe were never above the roughly 100 million Kelvin required for helium fusion.
D) No one knows-this is one of the major mysteries in astronomy.
F) B) and D)
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A) The shock wave of the Big Bang caused ripples that expanded outward with time.
B) The energy released when the strong force froze out of the GUT force caused shock waves that produced ripples in the universe.
C) Matter and antimatter particles that spontaneously formed from high-energy photons caused perturbations in the radiation field.
D) The annihilation of matter and antimatter particles caused tiny explosions that perturbed the radiation field.
E) Quantum mechanics requires that the energy fields at any point in space be continually fluctuating as a result of the uncertainty principle.
G) A) and D)
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A) They can form a complete atom.
B) The combined mass of the two particles is completely transformed into energy (photons) .
C) They fuse to make a heavier particle.
D) The question makes no sense,since antimatter does not really exist.
F) All of the above
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A) The universe is geometrically "flat" (in the four dimensions of spacetime) .
B) The matter density (both luminous and dark matter combined) in the universe is only about one-fourth of the critical density.
C) Dark energy,whatever it is,represents the majority of the energy content of the universe.
D) The universe is at least 20 billion years old.
F) None of the above
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A) 10⁻¹⁰ second
B) 10⁻³⁵ second
C) 10⁻⁴³ second
D) 3 minutes
E) 300,000 years
G) B) and C)
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A) They add further support to the idea that dark matter really exists and is made of non-ordinary (nonbaryonic) matter,such as WIMPs.
B) They do not support the conclusion that dark matter is the dominant form of matter in the universe.
C) They tell us that dark matter probably exists,but that it must be made of ordinary (baryonic) matter in the form of MACHOs.
D) They tell us that dark matter was produced during the era of nuclei.
F) B) and C)
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A) The most advanced telescopes are able to see back to this era in the universe.
B) Detectors on Earth have received photons and high-energy particles from this era.
C) Temperatures in the center of the Sun can reproduce the conditions during this era.
D) Particle accelerators on Earth can reach energies equivalent to the high temperatures of this era and have produced particles predicted by the electroweak theory.
E) We have no direct evidence of the electroweak force.
G) B) and C)
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A) before the Big Bang.
B) before the Planck time.
C) after the Planck time.
D) after inflation.
E) after the GUT era.
G) A) and D)
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A) dense
B) small
C) hot
D) filled with intense radiation
F) B) and C)
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A) 380,000 years after the Big Bang.
B) one ten-billionth of a second after the Big Bang.
C) 10-45 seconds after the Big Bang.
D) 10 billion years ago.
F) C) and D)
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A) (1) the theory correctly predicts that the universe should be expanding;(2) the theory predicts the existence of and the specific characteristics of the observed cosmic microwave background.
B) (1) the theory predicts the episode of inflation that we think occurred in the early universe;(2) the theory predicts the existence of large quantities of dark matter.
C) (1) the theory correctly predicts that the universe should be expanding;(2) the theory correctly predicts the observed ratio of spiral to elliptical galaxies in the universe.
D) (1) the theory predicts the existence of and the specific characteristics of the observed cosmic microwave background;(2) the theory correctly predicts the observed overall chemical composition of the universe.
F) B) and C)
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A) We do not yet have a theory that links quantum mechanics and general relativity.
B) We do not understand the properties of antimatter.
C) We do not know how much energy existed during that time.
D) It was a time period from which we cannot receive radiation.
E) The Planck era was the time before the Big Bang,and we cannot describe what happened before that instant.
G) A) and E)
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A) unify all four forces.
B) unify gravity and the electromagnetic and weak forces.
C) unify gravity and the strong and weak forces.
D) unify the strong force and the electromagnetic and weak forces.
E) unify the electromagnetic and weak forces.
G) C) and D)
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A) Inflation predicts that gravity would have been very strong and thereby would have concentrated mass into seeds.
B) Inflation tells us that the universe should have a "flat" overall geometry,and this led to the flat disks of galaxies.
C) Inflation predicts that temperatures and densities should have become nearly equal throughout the universe.
D) Inflation would have caused random,microscopic quantum fluctuations to grow so large in size that they became the seeds of structure.
F) All of the above
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