Questão 1
Questão
What does it mean that the universe is homogenous?
Responda
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The universe looks the same from every perspective
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Galaxies are generally distributed evenly throughout the universe
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All stars in all galaxies have planetary systems just like ours
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The universe has looked the same at all times in its history
Questão 2
Questão
What do astronomers mean when they say that the universe is isotropic?
Responda
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More distant parts of the universe look just like nearby parts
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Intergalactic gas has the same density everywhere in the universe
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The laws of physics apply everywhere in the universe
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The universe is the same in every direction
Questão 3
Questão
Cosmological redshifts are calculated from observations of spectral lines from
Responda
-
individual stars in different galaxies
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clouds of dust and gas in different galaxies
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spectra of entire galaxies
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rotations of the disks of distant galaxies
Questão 4
Questão
Astronomers observe that all galaxies are moving away from the Milky Way. According to the cosmological principle, this observation suggests that
Responda
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the Milky Way is at the center of the universe
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the Milky Way must be at the center of the expansion
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the Big Bang occurred at the current location of the Milky Way
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an observer in a distant galaxy would make the same observation
Questão 5
Questão
Some galaxies have redshifts (z) that if equated to Vr/c correspond to velocities greater than the speed of light. Special relativity is not violated
Responda
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because of relativistic beaming
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because it's a trick of the measurement angle
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because redshifts carry no information
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because those velocities do not measure motion through space
Questão 6
Questão
The Big Bang theory predicted
Responda
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the Hubble law
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the cosmic microwave background radiation
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the cosmological principle
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the abundance of helium
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the period-luminosity relationship of Cepheid variables
Questão 7
Questão
The simplest way to estimate the age of the universe is from
Responda
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using the slope of Hubble's Law
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the age of Moon rocks
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models of stellar evolution
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measurements of the abundances of elements
Questão 8
Questão
The CMB includes information about
Responda
-
the age of the universe
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the temperature of the early universe
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the density of the early universe
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density fluctuations in the early universe
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the motion of Earth around the center of the Milky Way
Questão 9
Questão
Repeated measurements showing that the current helium abundance is much less than the value predicted by the Big Bang would imply that
Responda
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some part of the Big Bang theory is incorrect or incomplete
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the current helium abundance is wrong
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scientists don't know how to measure helium abundances
Questão 10
Questão
If the density of the universe is higher than the critical density, the universe will
Questão 11
Questão
Dark energy has been hypothesized to solve which problem?
Responda
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the universe is expanding
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the cosmic microwave background radiation is too smooth
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the expansion of the universe is accelerating
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stars orbit the centers of galaxies too fast
Questão 12
Questão
What problems of cosmology does inflation solve?
Responda
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flatness
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horizon
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fluctuation
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sphere
Questão 13
Questão
The first stars formed in the universe had [blank_start]fewer[blank_end] heavy elements and [blank_start]higher[blank_end] mass than the stars formed today.
Questão 14
Questão
We expect the kinds of galaxies that we see at a redshift of z = 4 to be:
Responda
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much like we see today
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smaller and much more irregular looking than today
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far more numerous but with more spiral galaxies
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larger versions of what we see today
Questão 15
Questão
Place the following in order of size, from smallest to largest.
[blank_start]a star[blank_end]
[blank_start]star clusters[blank_end]
[blank_start]a galaxy[blank_end][blank_start]the Local Group[blank_end]
[blank_start]Virgo Cluster[blank_end][blank_start]Laniakea[blank_end]
[blank_start]a wall[blank_end]
Responda
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a star
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star clusters
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a galaxy
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the Local Group
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Virgo Cluster
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Laniakea
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a wall
Questão 16
Questão
The dominant force in the formation of galaxies is
Questão 17
Questão
Larger galaxies form from the merging of small protogalaxies. That process is similar to the formation of:
Responda
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stars
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planets
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molecular clouds
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asteroids
Questão 18
Questão
Which of the following is a characteristic difference between cold and hot dark matter?
Questão 19
Questão
The dominant factor in the formation of galaxies is the distribution of [blank_start]dark matter[blank_end] in the early universe.