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AST Exam 3 Study Guide Questions and Answers with Verified Solutions
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AST Exam 3 Study Guide Questions and Answers with Verified Solutions
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AST Exam 3 Study Guide Questions and Answerswith Verified Solutions
What evidence do we have for the existence for "dark energy"? - ANSWER The
expansion of the universe is accelerating.
Compared to our Sun, most stars in the halo are - ANSWER old, red, and dim
and have fewer heavy elements.
In the milky way, we see two main populations of stars. Which of the following
statements about these populations is true? - ANSWER Disk stars tend to have
heavy element content similar to the Sun.
Many large clusters of galaxies contain a lot of ellipticals and few spirals, while
smaller clusters of
galaxies contain few elliptical and more spirals. Why do we think this happens? -
ANSWER Galaxy collisions, that tend to strip gas from spirals, are more
common in large clusters.
Which of the following statements best summarizes current observations
concerning dark matter in individual galaxies and in clusters of galaxies? -
ANSWER Dark matter is the dominant form of mass in both clusters and in
individual galaxies.
How is the energy that powers radio galaxies, quasars, and other active galactic
nuclei produced? - ANSWER By gravity, which converts the gravitational,
potential energy of matter falling toward a central black hole into kinetic energy,
, which is then converted into thermal energy by collisions among the particles of
matter.
Hubble's "constant" is a number that relates - ANSWER a galaxy's redshift to its
distance.
Which of the following is a consequence of Hubble's Law? - ANSWER The more
distant a galaxy is from us, the faster it moves away from us.
How do we know that quasars are no larger than our solar system? - ANSWER
They vary in brightness on a timescale of days.
Where is the Sun located within the Milky Way? - ANSWER In the disk, about
halfway from the center to the edge.
The rotation curve (rotation velocity vs. distance from center) for objects in our
Galaxy... - ANSWER Is flat and remains flat at radii beyond the visible edge of
the Galaxy indicating that significant dark matter is present.
Some regions among the plane of the Milky Way appear dark because -
ANSWER Stars in that region are hidden by dark dust clouds.
Which of the following is not a possible scenario for the past and future
development of the universe according to the available evidence? - ANSWER
The universe could have existed in in an infinitely large state for all eternity.
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