Question 1

What is the grand unified theory and why is it important to scientists?

Accepted Answer

The grand unified theory is the predicti

Question 2

What is the scientific evidence that supports the Big Bang?

Accepted Answer

The evidence includes expansion of the u

Question 3

The very small detected irregularities in the uniformity of the cosmic microwave background are considered to be important in the study of the evolution of our universe because they

Accepted Answer

A)  were the seeds of supermassive black holes around which all galaxies then formed. 
B)  are thought to have led to the development of the present concentrations of matter and energy in superclusters of galaxies. 
C)  are thought to contain most of the elusive "missing matter" in the form of energy concentration in the universe. 
D)  show us how non-uniform the Big Bang explosion was. 
A)  were the seeds of supermassive black holes around which all galaxies then formed. 
B)  are thought to have led to the development of the present concentrations of matter and energy in superclusters of galaxies. 
C)  are thought to contain most of the elusive "missing matter" in the form of energy concentration in the universe. 
D)  show us how non-uniform the Big Bang explosion was.

Question 4

What evidence led astronomers to understand that the universe is speeding up in its expansion?

Accepted Answer

Through observations of Type Ia supernov

Question 5

When the intensity of the cosmic microwave background radiation is plotted against wavelength,what is the shape of the resulting curve?

Accepted Answer

A)  Emission lines from hydrogen gas,strongest and most densely concentrated in the microwave region 
B)  A blackbody curve modified by many deep,overlapping absorption lines and several emission lines 
C)  A composite of many overlapping blackbody curves from gas clouds of different temperatures,peaking in the microwave region 
D)  An almost perfect blackbody spectrum peaking in the microwave region 
A)  Emission lines from hydrogen gas,strongest and most densely concentrated in the microwave region 
B)  A blackbody curve modified by many deep,overlapping absorption lines and several emission lines 
C)  A composite of many overlapping blackbody curves from gas clouds of different temperatures,peaking in the microwave region 
D)  An almost perfect blackbody spectrum peaking in the microwave region

Question 6

What is dark energy?

Accepted Answer

A)  It is the same as dark matter. 
B)  It is the same as normal matter. 
C)  It is the same as normal radiation energy. 
D)  It is an unknown type of energy that causes a form of "antigravity." 
A)  It is the same as dark matter. 
B)  It is the same as normal matter. 
C)  It is the same as normal radiation energy. 
D)  It is an unknown type of energy that causes a form of "antigravity."

Question 7

Isotropic means

Accepted Answer

A)  viewing a blueshift in one direction and a redshift in the opposite direction. 
B)  accelerating over time. 
C)  every region is the same as every other region. 
D)  looking the same in every direction. 
A)  viewing a blueshift in one direction and a redshift in the opposite direction. 
B)  accelerating over time. 
C)  every region is the same as every other region. 
D)  looking the same in every direction.

Question 8

The cosmological redshift of the light from very distant galaxies is caused by

Accepted Answer

A)  the expansion of space,stretching the photon's wavelength while the photon is traveling toward us. 
B)  absorption of blue light by interstellar dust between us and the galaxy so that only the red wavelengths reach us. 
C)  the rotation of the universe around its center (faster at greater distances from us). 
D)  the Doppler shift,in which the photon's wavelength is stretched as the photon is being emitted by the galaxy's motion away from us through space. 
A)  the expansion of space,stretching the photon's wavelength while the photon is traveling toward us. 
B)  absorption of blue light by interstellar dust between us and the galaxy so that only the red wavelengths reach us. 
C)  the rotation of the universe around its center (faster at greater distances from us). 
D)  the Doppler shift,in which the photon's wavelength is stretched as the photon is being emitted by the galaxy's motion away from us through space.

Question 9

The Hubble law states that the more distant a galaxy,the less its redshift and the slower it is receding from us.

Accepted Answer

A) True 
 B)False

Question 10

The cosmological principle holds true for

Accepted Answer

A)  very large regions in outer space. 
B)  the distribution of stars in an object as small as a galaxy. 
C)  both of these. 
D)  neither of these. 
A)  very large regions in outer space. 
B)  the distribution of stars in an object as small as a galaxy. 
C)  both of these. 
D)  neither of these.

Question 11

The weak force

Accepted Answer

A)  acted only during the Big Bang and has no known role in the universe at the present time. 
B)  holds the quarks together inside a proton or neutron. 
C)  acts during certain kinds of radioactive decay. 
D)  attracts the electrons to the nucleus,holding the atom together. 
A)  acted only during the Big Bang and has no known role in the universe at the present time. 
B)  holds the quarks together inside a proton or neutron. 
C)  acts during certain kinds of radioactive decay. 
D)  attracts the electrons to the nucleus,holding the atom together.

Question 12

The universe has been expanding for billions of years.

Accepted Answer

A) True 
 B)False

Question 13

Why did Einstein introduce his cosmological constant into the original field equations for general relativity?

Accepted Answer

A)  The constant was necessary to make the solutions describe an expanding universe. 
B)  Experimental evidence at this time (before Hubble)suggested a static universe,and this constant was required to produce static solutions. 
C)  The constant represented the acceleration of gravity near Earth's surface,and it was necessary in order to make the nonrelativistic limit of the solutions compatible with Newton's results. 
D)  The constant represented the speed of light,and its inclusion was necessary to produce solutions,which were compatible with the postulates of special relativity. 
A)  The constant was necessary to make the solutions describe an expanding universe. 
B)  Experimental evidence at this time (before Hubble)suggested a static universe,and this constant was required to produce static solutions. 
C)  The constant represented the acceleration of gravity near Earth's surface,and it was necessary in order to make the nonrelativistic limit of the solutions compatible with Newton's results. 
D)  The constant represented the speed of light,and its inclusion was necessary to produce solutions,which were compatible with the postulates of special relativity.

Question 14

What is the cosmic microwave background radiation?

Accepted Answer

A)  An almost-uniform background radiation from distant,unresolved,overlapping galaxies 
B)  Radiation left over from the Big Bang,after the universe expanded and cooled 
C)  A uniform background of radiation from electrons spiraling in weak intergalactic magnetic fields 
D)  Radiation from a very tenuous,ionized gas that fills the universe equally in all directions 
A)  An almost-uniform background radiation from distant,unresolved,overlapping galaxies 
B)  Radiation left over from the Big Bang,after the universe expanded and cooled 
C)  A uniform background of radiation from electrons spiraling in weak intergalactic magnetic fields 
D)  Radiation from a very tenuous,ionized gas that fills the universe equally in all directions

Question 15

In a universe that is uniformly expanding more quickly than ours,the slope of a Hubble graph would be

Accepted Answer

A)  steeper. 
B)  shallower. 
C)  at the same slope. 
D)  curved rather than a straight line. 
A)  steeper. 
B)  shallower. 
C)  at the same slope. 
D)  curved rather than a straight line.

Question 16

Because of the general expansion of space,all distant galaxies appear to be moving away from us,with speeds that increase with distance from our Galaxy.Observers in one of these distant galaxies would apparently see all galaxies

Accepted Answer

A)  on one side of the observers moving toward them and all galaxies on the other side moving away from them;the more distant the galaxy,the faster its motion. 
B)  moving away from them,with the more distant galaxies moving faster. 
C)  moving away from them,with the closer galaxies moving faster. 
D)  moving toward them,with the more distant galaxies moving faster. 
A)  on one side of the observers moving toward them and all galaxies on the other side moving away from them;the more distant the galaxy,the faster its motion. 
B)  moving away from them,with the more distant galaxies moving faster. 
C)  moving away from them,with the closer galaxies moving faster. 
D)  moving toward them,with the more distant galaxies moving faster.

Question 17

The effect that makes the cosmic microwave background appear slightly warmer in one direction and cooler in the opposite direction is

Accepted Answer

A)  the focusing effect of the gravitational field of the local galaxy on the radiation. 
B)  the presence of many extra sources of the radiation in one direction. 
C)  a basic asymmetry in the background radiation,related to its origin. 
D)  the Doppler shift,caused by motion of our Galaxy through space toward the constellation Leo. 
A)  the focusing effect of the gravitational field of the local galaxy on the radiation. 
B)  the presence of many extra sources of the radiation in one direction. 
C)  a basic asymmetry in the background radiation,related to its origin. 
D)  the Doppler shift,caused by motion of our Galaxy through space toward the constellation Leo.

Question 18

In a universe that is uniformly expanding more slowly than ours,the slope of a Hubble graph would be

Accepted Answer

A)  steeper. 
B)  shallower. 
C)  at the same slope. 
D)  curved rather than a straight line. 
A)  steeper. 
B)  shallower. 
C)  at the same slope. 
D)  curved rather than a straight line.

Question 19

What significant event occurred about 380,000 years after the Big Bang started?

Accepted Answer

A)  The universe became transparent to radiation. 
B)  All of the present galaxies in the universe were formed within a short time span. 
C)  The temperature of the radiation decreased to 2.76 K. 
D)  The solar system was formed. 
A)  The universe became transparent to radiation. 
B)  All of the present galaxies in the universe were formed within a short time span. 
C)  The temperature of the radiation decreased to 2.76 K. 
D)  The solar system was formed.

Question 20

The value of the accepted Hubble constant is about 73 km s-1 Mpc-1.

Accepted Answer

A) True 
 B)False

What is the grand unified theory and why is it important to scientists?

What is the scientific evidence that supports the Big Bang?

The very small detected irregularities in the uniformity of the cosmic microwave background are considered to be important in the study of the evolution of our universe because they

What evidence led astronomers to understand that the universe is speeding up in its expansion?

When the intensity of the cosmic microwave background radiation is plotted against wavelength,what is the shape of the resulting curve?

What is dark energy?

Isotropic means

The cosmological redshift of the light from very distant galaxies is caused by

The Hubble law states that the more distant a galaxy,the less its redshift and the slower it is receding from us.

The cosmological principle holds true for

The weak force

The universe has been expanding for billions of years.

Why did Einstein introduce his cosmological constant into the original field equations for general relativity?

What is the cosmic microwave background radiation?

In a universe that is uniformly expanding more quickly than ours,the slope of a Hubble graph would be

Because of the general expansion of space,all distant galaxies appear to be moving away from us,with speeds that increase with distance from our Galaxy.Observers in one of these distant galaxies would apparently see all galaxies

The effect that makes the cosmic microwave background appear slightly warmer in one direction and cooler in the opposite direction is

In a universe that is uniformly expanding more slowly than ours,the slope of a Hubble graph would be

What significant event occurred about 380,000 years after the Big Bang started?

The value of the accepted Hubble constant is about 73 km s^-1 Mpc^-1.

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

What is the grand unified theory and why is it important to scientists?

What is the scientific evidence that supports the Big Bang?

The very small detected irregularities in the uniformity of the cosmic microwave background are considered to be important in the study of the evolution of our universe because they

What evidence led astronomers to understand that the universe is speeding up in its expansion?

When the intensity of the cosmic microwave background radiation is plotted against wavelength,what is the shape of the resulting curve?

What is dark energy?

Isotropic means

The cosmological redshift of the light from very distant galaxies is caused by

The Hubble law states that the more distant a galaxy,the less its redshift and the slower it is receding from us.

The cosmological principle holds true for

The weak force

The universe has been expanding for billions of years.

Why did Einstein introduce his cosmological constant into the original field equations for general relativity?

What is the cosmic microwave background radiation?

In a universe that is uniformly expanding more quickly than ours,the slope of a Hubble graph would be

Because of the general expansion of space,all distant galaxies appear to be moving away from us,with speeds that increase with distance from our Galaxy.Observers in one of these distant galaxies would apparently see all galaxies

The effect that makes the cosmic microwave background appear slightly warmer in one direction and cooler in the opposite direction is

In a universe that is uniformly expanding more slowly than ours,the slope of a Hubble graph would be

What significant event occurred about 380,000 years after the Big Bang started?

The value of the accepted Hubble constant is about 73 km s-1 Mpc-1.

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

The value of the accepted Hubble constant is about 73 km s^-1 Mpc^-1.