Question 1

The formation of the solar system occurred at what point in the history of the universe?

Accepted Answer

A)  Right at the beginning 
B)  During the first third 
C)  About halfway through 
D)  About two-thirds of the way through 
A)  Right at the beginning 
B)  During the first third 
C)  About halfway through 
D)  About two-thirds of the way through

Question 2

The cosmic background radiation is

Accepted Answer

A)  the flux of visible radiation contributed to empty space by all visible stars in the universe. 
B)  the beam of atomic nuclei,also known as cosmic rays,which rain down continuously on Earth from all directions in space. 
C)  the radio noise generated by Earth-bound transmitters,spreading out into space since about 1920. 
D)  low-intensity radio noise,with a 3 K blackbody temperature,almost uniform in intensity in all directions. 
A)  the flux of visible radiation contributed to empty space by all visible stars in the universe. 
B)  the beam of atomic nuclei,also known as cosmic rays,which rain down continuously on Earth from all directions in space. 
C)  the radio noise generated by Earth-bound transmitters,spreading out into space since about 1920. 
D)  low-intensity radio noise,with a 3 K blackbody temperature,almost uniform in intensity in all directions.

Question 3

The isotropy of the cosmic microwave background radiation (same temperature in all directions)indicates that

Accepted Answer

A)  the universe has always been dominated by matter. 
B)  the universe had an early period of inflation in which regions initially in contact were carried out of contact with each other. 
C)  the universe did not begin to expand significantly until after the era of recombination. 
D)  regions that appear to us to be on opposite sides of the visible universe are in fact in close contact with each other. 
A)  the universe has always been dominated by matter. 
B)  the universe had an early period of inflation in which regions initially in contact were carried out of contact with each other. 
C)  the universe did not begin to expand significantly until after the era of recombination. 
D)  regions that appear to us to be on opposite sides of the visible universe are in fact in close contact with each other.

Question 4

For which objects in the universe has the Hubble relation been shown to hold experimentally?

Accepted Answer

A)  Only stars in the near neighborhood of the Sun,in our Galaxy 
B)  Distant galaxies only 
C)  Galaxies in the Local Group,in the near vicinity of the Milky Way 
D)  All objects in the universe,from planets and stars out to the farthest galaxies 
A)  Only stars in the near neighborhood of the Sun,in our Galaxy 
B)  Distant galaxies only 
C)  Galaxies in the Local Group,in the near vicinity of the Milky Way 
D)  All objects in the universe,from planets and stars out to the farthest galaxies

Question 5

Dark energy accounts for about what percentage of the contents of the universe.

Accepted Answer

A)  4% 
B)  24% 
C)  76% 
D)  97% 
A)  4% 
B)  24% 
C)  76% 
D)  97%

Question 6

In stating his paradox,Olber expected the night sky to be bright and not dark as we see it because he thought that

Accepted Answer

A)  the space between the stars would be filled with gas (such as the Orion Nebula),which would emit light. 
B)  airglow and auroral light excited by solar particles,by his calculations,would produce significant illumination in our atmosphere. 
C)  Earth's atmosphere should refract (bend)the sunlight around Earth to illuminate the night sky. 
D)  every line of sight should eventually intersect a star in an infinite universe randomly scattered with stars. 
A)  the space between the stars would be filled with gas (such as the Orion Nebula),which would emit light. 
B)  airglow and auroral light excited by solar particles,by his calculations,would produce significant illumination in our atmosphere. 
C)  Earth's atmosphere should refract (bend)the sunlight around Earth to illuminate the night sky. 
D)  every line of sight should eventually intersect a star in an infinite universe randomly scattered with stars.

Question 7

Astrophysicists believe the dominant hot spots in the cosmic background radiation should be about 1° in angular size if the universe is flat.What do experimental measurements of this angular size tell us?

Accepted Answer

A)  The measurements show angular sizes of less than 1°,which suggests that the universe is spherical. 
B)  The measurements show angular separations of about 1°,which suggests that the universe is flat. 
C)  The measurements show angular sizes larger than 1°,which suggests that the universe is hyperbolic. 
D)  The measurements thus far are inconclusive. 
A)  The measurements show angular sizes of less than 1°,which suggests that the universe is spherical. 
B)  The measurements show angular separations of about 1°,which suggests that the universe is flat. 
C)  The measurements show angular sizes larger than 1°,which suggests that the universe is hyperbolic. 
D)  The measurements thus far are inconclusive.

Question 8

In cosmology,the constant that is intimately related to the present "age" of the universe is

Accepted Answer

A)  1/G,the inverse of the universal gravitational constant. 
B)  1/H0,the inverse of the constant in Hubble's universal expansion law. 
C)  The constant in Wien's law of radiation,representing the redness of a spectrum for a certain temperature. 
D)  The inverse of 10-43 s,the Planck time at which space and time came into existence 
A)  1/G,the inverse of the universal gravitational constant. 
B)  1/H0,the inverse of the constant in Hubble's universal expansion law. 
C)  The constant in Wien's law of radiation,representing the redness of a spectrum for a certain temperature. 
D)  The inverse of 10-43 s,the Planck time at which space and time came into existence

Question 9

The cosmic microwave background was discovered by

Accepted Answer

A)  rocket-borne telescopes while they were searching for X-ray sources in space. 
B)  the Voyager 2 spacecraft during one of its "coasting" periods between planetary encounters. 
C)  the IRAS satellite,which produced an all-sky infrared survey. 
D)  scientists testing a new antenna and receiver for satellite communications. 
A)  rocket-borne telescopes while they were searching for X-ray sources in space. 
B)  the Voyager 2 spacecraft during one of its "coasting" periods between planetary encounters. 
C)  the IRAS satellite,which produced an all-sky infrared survey. 
D)  scientists testing a new antenna and receiver for satellite communications.

Question 10

If the redshift of a galaxy is greater than another,it is also at a

Accepted Answer

A)  shorter distance. 
B)  lower temperature. 
C)  greater temperature. 
D)  greater distance. 
A)  shorter distance. 
B)  lower temperature. 
C)  greater temperature. 
D)  greater distance.

Question 11

The cosmic microwave background radiation is not uniform over the sky: It is slightly hotter toward the constellation Leo and slightly cooler in the opposite direction toward Aquarius.Why?

Accepted Answer

A)  The background radiation really is uniform;the observed difference is due to Earth's motion through the universe. 
B)  That is the way the universe began: hotter in one direction and cooler in the other. 
C)  The difference is probably a statistical fluctuation,and therefore not real. 
D)  Earth is slightly off-center in the universe,so one side of the universe is a bit closer and the other side is a bit farther away. 
A)  The background radiation really is uniform;the observed difference is due to Earth's motion through the universe. 
B)  That is the way the universe began: hotter in one direction and cooler in the other. 
C)  The difference is probably a statistical fluctuation,and therefore not real. 
D)  Earth is slightly off-center in the universe,so one side of the universe is a bit closer and the other side is a bit farther away.

Question 12

If space has a closed geometry,what will happen to two initially parallel flashlight beams as they traverse billions of light-years of space?

Accepted Answer

A)  They will remain parallel. 
B)  They will gradually diverge (move apart)to a maximum separation,and then gradually converge and cross. 
C)  They will gradually converge (move together)and eventually cross. 
D)  They will gradually diverge (move apart). 
A)  They will remain parallel. 
B)  They will gradually diverge (move apart)to a maximum separation,and then gradually converge and cross. 
C)  They will gradually converge (move together)and eventually cross. 
D)  They will gradually diverge (move apart).

Question 13

What method is being used to discover whether we live in an unbounded universe,in which expansion will continue forever,or a bounded universe,in which expansion will eventually turn into contraction and lead us to recollapse?

Accepted Answer

A)  Careful monitoring of the Moon-Earth distance to detect the slowdown of the expansion of the universe 
B)  Measurement of the deviation from uniformity of the cosmic background radiation 
C)  Measurement of the curvature of the Hubble relationship,v = H0d,at large distances 
D)  Measurement of the bending of light by distant galaxies as it follows the curvature of space 
A)  Careful monitoring of the Moon-Earth distance to detect the slowdown of the expansion of the universe 
B)  Measurement of the deviation from uniformity of the cosmic background radiation 
C)  Measurement of the curvature of the Hubble relationship,v = H0d,at large distances 
D)  Measurement of the bending of light by distant galaxies as it follows the curvature of space

Question 14

Who discovered the radiation left over from the Big Bang,the so-called "cosmic microwave background"?

Accepted Answer

A)  Anthony Hewish and Jocelyn Bell 
B)  Robert Dicke and P.J.E.Peebles 
C)  Arno Penzias and Robert Wilson 
D)  Ralph Alpher and George Gamow 
A)  Anthony Hewish and Jocelyn Bell 
B)  Robert Dicke and P.J.E.Peebles 
C)  Arno Penzias and Robert Wilson 
D)  Ralph Alpher and George Gamow

Question 15

The farther away a galaxy is,the more its light is redshifted,as seen by us on Earth.This redshift-distance law is caused by

Accepted Answer

A)  energy losses.The universe does not really expand,but photons lose energy as they travel,hence their wavelength lengthens.Photons from more distant galaxies have traveled farther,are more "tired," and so are more redshifted. 
B)  the expansion of space itself,which stretches the wavelength of the photon.The longer the photon travels,the more space expands and the more the photon is redshifted during the time it is traveling. 
C)  the gravitational redshift.Photons leaving a more distant galaxy have traveled farther through the galaxy's gravitational field,so they have lost more energy and are more redshifted. 
D)  the Doppler shift of light leaving a moving object.More distant galaxies are moving faster through space,so their light is more strongly Doppler-shifted toward the red wavelengths. 
A)  energy losses.The universe does not really expand,but photons lose energy as they travel,hence their wavelength lengthens.Photons from more distant galaxies have traveled farther,are more "tired," and so are more redshifted. 
B)  the expansion of space itself,which stretches the wavelength of the photon.The longer the photon travels,the more space expands and the more the photon is redshifted during the time it is traveling. 
C)  the gravitational redshift.Photons leaving a more distant galaxy have traveled farther through the galaxy's gravitational field,so they have lost more energy and are more redshifted. 
D)  the Doppler shift of light leaving a moving object.More distant galaxies are moving faster through space,so their light is more strongly Doppler-shifted toward the red wavelengths.

Question 16

What is "dark energy"?

Accepted Answer

A)  The energy associated with the matter that has fallen into a black hole 
B)  The matter-energy needed to bridge the gap between the energy we see or infer and the energy needed to make the universe flat 
C)  The energy associated with "dark matter" 
D)  The unseen matter-energy needed to make the observed curvature of space spherical (as we believe it should be),whereas the observed matter-energy only makes it hyperbolic 
A)  The energy associated with the matter that has fallen into a black hole 
B)  The matter-energy needed to bridge the gap between the energy we see or infer and the energy needed to make the universe flat 
C)  The energy associated with "dark matter" 
D)  The unseen matter-energy needed to make the observed curvature of space spherical (as we believe it should be),whereas the observed matter-energy only makes it hyperbolic

Question 17

What causes cosmological redshift of photons that reach us from distant galaxies?

Accepted Answer

A)  The photons have moved from high gravitational field regions toward lower fields,thereby becoming reddened. 
B)  The photons were emitted from the galaxies much earlier in time when the overall temperature of matter was much lower.Hence,the observed photons are redder,the farther away from Earth that they were produced. 
C)  The photons have traveled across space that has been expanding and their wavelengths have expanded with it,becoming redder. 
D)  The photons were emitted by objects that were moving rapidly away from us,and thereby have been reddened by the Doppler effect. 
A)  The photons have moved from high gravitational field regions toward lower fields,thereby becoming reddened. 
B)  The photons were emitted from the galaxies much earlier in time when the overall temperature of matter was much lower.Hence,the observed photons are redder,the farther away from Earth that they were produced. 
C)  The photons have traveled across space that has been expanding and their wavelengths have expanded with it,becoming redder. 
D)  The photons were emitted by objects that were moving rapidly away from us,and thereby have been reddened by the Doppler effect.

Question 18

Recent results from very bright supernovae in very distant galaxies seem to indicate that the expansion of the universe

Accepted Answer

A)  is continuing at a constant rate and has done so since just after the Big Bang. 
B)  has now stopped and the universe will shortly begin to contract again toward a recollapse. 
C)  is accelerating (speeding up). 
D)  is decelerating (slowing down). 
A)  is continuing at a constant rate and has done so since just after the Big Bang. 
B)  has now stopped and the universe will shortly begin to contract again toward a recollapse. 
C)  is accelerating (speeding up). 
D)  is decelerating (slowing down).

Question 19

Which of the following statements does NOT correctly describe the universe at the era of recombination?

Accepted Answer

A)  The universe was about 380,000 years old. 
B)  Electrons and protons combined to form neutral hydrogen atoms. 
C)  The temperature of the universe was about 3 K. 
D)  The universe became transparent to radiation. 
A)  The universe was about 380,000 years old. 
B)  Electrons and protons combined to form neutral hydrogen atoms. 
C)  The temperature of the universe was about 3 K. 
D)  The universe became transparent to radiation.

Question 20

The question,"If the universe is expanding,what is it expanding into?" can easily be answered with observations.

Accepted Answer

A) True 
 B)False

The formation of the solar system occurred at what point in the history of the universe?

The cosmic background radiation is

The isotropy of the cosmic microwave background radiation (same temperature in all directions)indicates that

For which objects in the universe has the Hubble relation been shown to hold experimentally?

Dark energy accounts for about what percentage of the contents of the universe.

In stating his paradox,Olber expected the night sky to be bright and not dark as we see it because he thought that

Astrophysicists believe the dominant hot spots in the cosmic background radiation should be about 1° in angular size if the universe is flat.What do experimental measurements of this angular size tell us?

In cosmology,the constant that is intimately related to the present "age" of the universe is

The cosmic microwave background was discovered by

If the redshift of a galaxy is greater than another,it is also at a

The cosmic microwave background radiation is not uniform over the sky: It is slightly hotter toward the constellation Leo and slightly cooler in the opposite direction toward Aquarius.Why?

If space has a closed geometry,what will happen to two initially parallel flashlight beams as they traverse billions of light-years of space?

What method is being used to discover whether we live in an unbounded universe,in which expansion will continue forever,or a bounded universe,in which expansion will eventually turn into contraction and lead us to recollapse?

Who discovered the radiation left over from the Big Bang,the so-called "cosmic microwave background"?

The farther away a galaxy is,the more its light is redshifted,as seen by us on Earth.This redshift-distance law is caused by

What is "dark energy"?

What causes cosmological redshift of photons that reach us from distant galaxies?

Recent results from very bright supernovae in very distant galaxies seem to indicate that the expansion of the universe

Which of the following statements does NOT correctly describe the universe at the era of recombination?

The question,"If the universe is expanding,what is it expanding into?" can easily be answered with observations.

Predicting the Motions of the Stars, Sun, and Moon

Decoding the Hidden Messages in Starlight

Analyzing Scales and Motions of the Universe

Exploring Our Evolving Solar System

Uncovering Earths Systems

Exploring Terrestrial Surface Processes and Atmospheres

Observing the Dynamic Giant Planets

Looking for Life Beyond Earth

Probing the Dynamic Sun

Observing Properties of Distant Stars

Inferring Patterns in Star Life Cycles

Predicting the Violent End of the Largest Stars

Exploring Our Galaxy

Investigating Other Galaxies

Filters

Exam 15: Observing the Evolution of the Universe

The formation of the solar system occurred at what point in the history of the universe?

The cosmic background radiation is

The isotropy of the cosmic microwave background radiation (same temperature in all directions)indicates that

For which objects in the universe has the Hubble relation been shown to hold experimentally?

Dark energy accounts for about what percentage of the contents of the universe.

In stating his paradox,Olber expected the night sky to be bright and not dark as we see it because he thought that

Astrophysicists believe the dominant hot spots in the cosmic background radiation should be about 1° in angular size if the universe is flat.What do experimental measurements of this angular size tell us?

In cosmology,the constant that is intimately related to the present "age" of the universe is

The cosmic microwave background was discovered by

If the redshift of a galaxy is greater than another,it is also at a

The cosmic microwave background radiation is not uniform over the sky: It is slightly hotter toward the constellation Leo and slightly cooler in the opposite direction toward Aquarius.Why?

If space has a closed geometry,what will happen to two initially parallel flashlight beams as they traverse billions of light-years of space?

What method is being used to discover whether we live in an unbounded universe,in which expansion will continue forever,or a bounded universe,in which expansion will eventually turn into contraction and lead us to recollapse?

Who discovered the radiation left over from the Big Bang,the so-called "cosmic microwave background"?

The farther away a galaxy is,the more its light is redshifted,as seen by us on Earth.This redshift-distance law is caused by

What is "dark energy"?

What causes cosmological redshift of photons that reach us from distant galaxies?

Recent results from very bright supernovae in very distant galaxies seem to indicate that the expansion of the universe

Which of the following statements does NOT correctly describe the universe at the era of recombination?

The question,"If the universe is expanding,what is it expanding into?" can easily be answered with observations.

Predicting the Motions of the Stars, Sun, and Moon

Decoding the Hidden Messages in Starlight

Analyzing Scales and Motions of the Universe

Exploring Our Evolving Solar System

Uncovering Earths Systems

Exploring Terrestrial Surface Processes and Atmospheres

Observing the Dynamic Giant Planets

Looking for Life Beyond Earth

Probing the Dynamic Sun

Observing Properties of Distant Stars

Inferring Patterns in Star Life Cycles

Predicting the Violent End of the Largest Stars

Exploring Our Galaxy

Investigating Other Galaxies

Filters