Astronomy final – Flashcards
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Which of the following is not a method of measuring distance?
- Using the brightness from a variable star.
-The temperature of the stars in the galaxy.
-The average magnitude of the globular clusters around a galaxy (globular cluster luminosity function).
-The spectral redshift of very distance galaxies.
-The movement of a star in the star called parallax.
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The temperature of the stars in the galaxy.
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The distance to our neighboring spiral galaxy, the Andromeda galaxy, was found by Edwin Hubble with:
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Cepheids of Population I in the spiral arms.
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Redshift surveys give us:
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a 3-D layout of galaxies in space.
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Astronomers found in 1998 that the universe is currently:
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expanding and accelerating
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The expansion rate of the Universe is:
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increasing.
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Hubble's Law is expressed as:
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v = H × D.
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The Hubble time is expressed as:
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1/H.
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What does Hubble's law imply about the history of the universe?
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The universe had a beginning and has expanded since, giving it a finite age.
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The presently accepted value of the Hubble constant gives an age of roughly:
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14 billion years
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The center of the universe:
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does not exist anywhere in space.
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The sky is dark at night:
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because all the light from all the objects in the universe hasn't arrived here yet.
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What is the Big Bang?
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The event that started the expansion of the universe.
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Astronomers know the universe is expanding because:
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galaxies farther away are moving away from us faster.
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On the surface of a sphere the shortest distance between two points is:
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an arc on a great circle
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The expansion rate of the Universe is:
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increasing
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Recent work with type I supernovae at great distances suggests the universe may in fact be accelerating its expansion, a discovery attributed to a newly found:
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dark energy.
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The two teams involved in the discovery of the cosmic microwave background radiation were at:
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Bell Labs and Princeton.
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Gravitational lensing of distant, faint irregular galaxies may be the key to:
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mapping the dark matter.
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How does gravitational lensing work?
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Light is bent by the force of gravity and curves as spacetime curves.
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What temperature has the Big Bang has cooled to by now?
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Just over 2.7K
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The discovery of the cosmic microwave background was important because:
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it was experimental verification of a prediction from the Big Bang theory.
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The period from about 100 seconds up to 15 minutes after the Big Bang is the:
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Nuclear Epoch.
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Before about 50,000 years after the Big Bang, the universe was:
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radiation dominated.
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Before about 4 billion years ago the universe was:
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matter dominated.
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At this time, the universe is:
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dark energy dominated.
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The stellar epoch, which we are still in today, began:
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about three billion years after the Big Bang, with Population I stars forming.
