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Cosmology
| Question | Answer |
|---|---|
| Where did the Big Bang occur? | Everywhere in the universe at once, because the entire universe (including space itself) was a point. |
| What is the resolution of the dilemma known as Olbers's paradox? | The universe is not infinite in extent and has evolved in time. |
| About what density of material, on average, is needed in order for the universe that we live in to be just barely bound, or "closed"? | about 5 atoms per cublic meter of space |
| What is the meaning of the assumption known as the cosmological principle that underlies much of the logic laid out in this chapter? | It states that the expansion of the universe would appear isotropic and identical for any two observers, even in two widely separate galaxies. |
| If the universe is open (forever expanding), its ultimate fate will be | cold and dark |
| The Hubble relation for galaxies is a relation between their | redshifts and distances |
| Current evidence implies that the age of the universe is | about 14 billion yrs |
| How does the age of the universe depend on the Hubble constant? | it is inversely proportional to it |
| We appear to be at the center of the Hubble flow. Why doesn't this violate the cosmological principle? | every other place in the universe also appears to be in the center |
| What observations have led scientists to postulate the existence of “dark energy”? | The most distant galaxies appear to be moving away from us more slowly than predicted by Hubble’s Law. |
| Which of the following is not a reason to believe that the early universe underwent a period of rapid expansion called inflation? | Inflation makes it possible to combine the four fundamental forces into one "superforce." |
| Currently, most of the mass of the universe is believed to consist of | non baryonic dark matter |
| In what area of physics is a theory needed to explain the Planck epoch? | quantum gravity |
| What started to form at the end of the galactic epoch? | stars |
| What happened to most of the primordial deuterium that the universe formed? | It was mostly converted into helium. |
| What is (a) GUT? | Grand Unified Theory |
| What is hot dark matter? | Lightweight particles, possibly like the neutrino |
| Currently, it is believed that most of the mass of the universe is | non-baryonic (dark) matter. |
Created by:
katesmarie
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