Term
The Hubble Sequence of galaxies is a way to classify galaxies by their
A. ages
B. masses
C. luminosities
D. diameters
E. morphologies (shapes) |
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Definition
Q: The Hubble Sequence of galaxies is a way to classify galaxies by their...
morphologies (shapes) |
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Term
The Hubble Law decisively rules out
A. a static universe
B. an infinite universe
C. a universe with a finite age
D. a universe whose expansion accelerates
E. a universe that will exist forever |
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Definition
Q: The Hubble Law decisively rules out...
a static universe |
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Term
The veracity (correctness) of the Big Bang model is challenged by
A. the detection of cosmic background radiation
B. the larger-than-expected rotation speeds of the disks of galaxies
C. the presence of a dark night sky
D. the discovery of an object with a redshift of ten
E. actually, the Big Bang model is consistent with all existing observations |
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Definition
Q: The veracity (correctness) of the Big Bang model is challenged by...
actually, the Big Bang model is consistent with all existing observations |
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Term
What is primarily responsible for cosmic redshifts?
A. Space has been expanding, so the wavelengths of the oldest photons have been stretched the most
B. Distant galaxies are older so that their redshifts are larger
C. Old, distant atoms have less energy than recently formed ones, making the light of distant atoms less energetic
D. The Big Bang hurtled galaxies through space such that the fastest ones are now the most distant
E. Light that passes through the most dust is the most redshifted |
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Definition
Q: What is primarily responsible for cosmic redshifts?
Space has been expanding, so the wavelengths of the oldest photons have been stretched the most |
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Term
Two galaxies are observed in the same cluster, but one has a redshift 15% greater than the other. The most likely cause of this difference is...
A. The more redshifted galaxy has a larger fraction of redder stars
B. The Hubble Law
C. The orbits of the galaxies around the cluster result in measurable peculiar motions
D. The more redshifted galaxy is 15% older
E. The light of the more redshifted galaxy is affected by a gravitational lens |
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Definition
Q: Two galaxies are observed in the same cluster, but one has a redshift 15% greater than the other. The most likely cause of this difference is...
The orbits of the galaxies around the cluster result in measurable peculiar motions |
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Term
Identify the FALSE statement: One implication of a plot of the highest quality observations of the redshifts and distances of galaxies is that...
A. Time has a beginning
B. The universe is expanding
C. The expansion of the universe is accelerating
D. We are at (or near) the center of the universe
E. Distances to very remote objects can be estimated well from their redshifts |
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Definition
Q: Identify the FALSE statement: One implication of a plot of the highest quality observations of the redshifts and distances of galaxies is that...
We are at (or near) the center of the universe |
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Term
The mass of a star is the result of...
A. its formation history
B. its dominant nuclear burning processes
C. the orbital properties of planets or companion stars
D. its main-sequence lifetime
E. its location inside its parent galaxy |
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Definition
Q: The mass of a star is the result of...
its formation history |
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Term
Sirius, the brightest star in the sky, appears about four times brighter than its neighbor Rigel, the seventh brightest star. Yet Rigel is 2000 times more luminous than Sirius in visible light. Explain.
A. Sirius must be more massive than Rigel.
B. Sirius must have a larger radius than Rigel.
C. Sirius is burning its nuclear fuel faster than Rigel.
D. Unlike Rigel, Sirius emits most of its light outside the visible spectrum.
E. Sirius is closer to the Earth than Rigel |
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Definition
Q: Sirius, the brightest star in the sky, appears about four times brighter than its neighbor Rigel, the seventh brightest star. Yet Rigel is 2000 times more luminous than Sirius in visible light. Explain.
Sirius is closer to the Earth than Rigel |
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Term
Suppose that you plot an H-R diagram for a cluster of stars and find that the brightest main sequence star has a luminosity of one solar luminosity. From this you can conclude
A. It would be impossible to find a planetary nebula in this cluster.
B. The cluster formed before the Milky Way.
C. The cluster is about 10 billion years old.
D. None of the stars in the cluster derive any of their energy from gravitational collapse.
E. No massive stars ever formed in the cluster. |
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Definition
Q: Suppose that you plot an H-R diagram for a cluster of stars and find that the brightest main sequence star has a luminosity of one solar luminosity. From this you can conclude...
The cluster is about 10 billion years old. |
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