39393881
Descripción
Test por Roman Jordan, actualizado hace 3 meses
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Creado por Roman Jordan
hace 3 meses
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Pregunta 1
Pregunta
What does it mean that the universe is homogenous?
Respuesta
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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
Pregunta 2
Pregunta
What do astronomers mean when they say that the universe is isotropic?
Respuesta
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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
Pregunta 3
Pregunta
Cosmological redshifts are calculated from observations of spectral lines from
Respuesta
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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
Pregunta 4
Pregunta
Astronomers observe that all galaxies are moving away from the Milky Way. According to the cosmological principle, this observation suggests that
Respuesta
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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
Pregunta 5
Pregunta
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
Respuesta
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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
Pregunta 6
Pregunta
The Big Bang theory predicted
Respuesta
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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
Pregunta 7
Pregunta
The simplest way to estimate the age of the universe is from
Respuesta
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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
Pregunta 8
Pregunta
The CMB includes information about
Respuesta
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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
Pregunta 9
Pregunta
Repeated measurements showing that the current helium abundance is much less than the value predicted by the Big Bang would imply that
Respuesta
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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
Pregunta 10
Pregunta
If the density of the universe is higher than the critical density, the universe will
Respuesta
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expand forever
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expand, but gradually slow down
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eventually collapse
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neither expand nor contract
Pregunta 11
Pregunta
Dark energy has been hypothesized to solve which problem?
Respuesta
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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
Pregunta 12
Pregunta
What problems of cosmology does inflation solve?
Respuesta
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flatness
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horizon
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fluctuation
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sphere
Pregunta 13
Pregunta
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.
Respuesta
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fewer
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more
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higher
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lower
Pregunta 14
Pregunta
We expect the kinds of galaxies that we see at a redshift of z = 4 to be:
Respuesta
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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
Pregunta 15
Pregunta
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]
Respuesta
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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
Pregunta 16
Pregunta
The dominant force in the formation of galaxies is
Respuesta
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gravity
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angular momentum
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the electromagnetic force
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the strong nuclear force
Pregunta 17
Pregunta
Larger galaxies form from the merging of small protogalaxies. That process is similar to the formation of:
Respuesta
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stars
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planets
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molecular clouds
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asteroids
Pregunta 18
Pregunta
Which of the following is a characteristic difference between cold and hot dark matter?
Respuesta
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temperature
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ability to emit radiation
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the way they clump under the influence of gravity
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mass density
Pregunta 19
Pregunta
The dominant factor in the formation of galaxies is the distribution of [blank_start]dark matter[blank_end] in the early universe.
Respuesta
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dark matter
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