Lecture 9 Query Optimization November 24, 2010 Dan Suciu -- CSEP544 Fall 20101.
LECTURE 24, NOVEMBER 30, 2010
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Transcript of LECTURE 24, NOVEMBER 30, 2010
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LECTURE 24, NOVEMBER 30, 2010
ASTR 101, SECTION 3INSTRUCTOR, JACK BRANDT
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ASTR 101-3, FALL 2010 2
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a) is explained by general relativity.b) results from the presence of dark matter.c) is a statement of Olbers’ paradox.d) is the cosmological principle.e) occurs if the universe is static and unchanging.
Question 6
The darkness of the sky in an infinite universe
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a) is explained by general relativity.b) results from the presence of dark matter.c) is a statement of Olbers’ paradox.d) is the cosmological principle.e) occurs if the universe is static and unchanging.
Question 6
The darkness of the sky in an infinite universe
If the universe is homogeneous in composition, and appears the same in
all directions, then for the sky to be dark, it must be either finite in age, or
evolving in time, or both.
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a) the size of the universe.b) the age of the universe.c) the shape of the universe.d) the temperature of the universe.e) the distance the universe has expanded.
Question 2
Hubble’s constant, H0, can be related to
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a) the size of the universe.b) the age of the universe.c) the shape of the universe.d) the temperature of the universe.e) the distance the universe has expanded.
Question 2
Hubble’s constant, H0, can be related to
H0 is currently estimated to be about 70 km/sec/Mpc.
This translates to an age for the universe of about 14
billion years.
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a) is infinitely old and getting larger.b) began expanding long ago, and has a finite age.c) will slow down because of dark matter.d) has repeatedly expanded and contracted.e) will eventually stop and recollapse.
Question 4
Hubble’s law implies that the universe
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a) is infinitely old and getting larger.b) began expanding long ago, and has a finite age.c) will slow down because of dark matter.d) has repeatedly expanded and contracted.e) will eventually stop and recollapse.
Question 4
Hubble’s law implies that the universe
Using the Hubble constant H0,
astronomers can estimate that the universe was born
about 14 billion years ago.
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a) the Milky Way must be located at the edge of the universe.
b) the Milky Way is at the center of the universe.
c) the universe is expanding.d) the sky is dark at night.e) the universe has not changed significantly.
Question 1
Because distant galaxies in every direction are moving away from us,
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a) the Milky Way must be located at the edge of the universe.
b) the Milky Way is at the center of the universe.
c) the universe is expanding.d) the sky is dark at night.e) the universe has not changed significantly.
Question 1
Because distant galaxies in every direction are moving away from us,
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a) a Doppler shift of the random motions of galaxies.
b) an aging of light as the universe ages.c) space itself expanding with time, stretching
light.d) the result of the Milky Way’s position at the
center.e) due to the temperature differences in the early
and late universe.
Question 3
The redshift of galaxies is explained best as
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a) a Doppler shift of the random motions of galaxies.
b) an aging of light as the universe ages.c) space itself expanding with time, stretching
light.d) the result of the Milky Way’s position at the
center.e) due to the temperature differences in the early
and late universe.
Question 3
The redshift of galaxies is explained best as
As the universe expands, photons of
radiation are stretched in
wavelength as they move through
space.
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