Question 1

An astronomer observes a set of galaxies that are exceptionally blue and have a large fraction of interactions.These galaxies are most likely:

Accepted Answer

A)  at high redshifts. 
B)  inside galaxy clusters. 
C)  ellipticals. 
D)  gravitationally lensed.

Question 2

Which of the following presents the most significant problem for mapping the positions of galaxies over the largest scales?

Accepted Answer

A)  the motions of galaxies toward filaments and walls 
B)  the evolution of galaxies with time 
C)  gravitational lensing 
D)  all of the above

Question 3

Why do redshift surveys require so much telescope time?

Accepted Answer

The answer of Why do redshift surveys require so much...

Question 4

How did the first galaxies in the Universe differ from those around us today?

Accepted Answer

A)  They were all elliptical. 
B)  They produced more red light. 
C)  They had more heavy elements. 
D)  They were much less massive.

Question 5

Suppose a star produces an ultraviolet photon during the Dark Ages.The photon is emitted from a continuum source with a wavelength between the absorption lines of neutral hydrogen,but it is absorbed as it travels a long distance through the neutral hydrogen.Why?

Accepted Answer

The answer of Suppose a star produces an ultraviolet photon...

Question 6

Which of the following discoveries would prove that the Universe is NOT isotropic,assuming all are made on very large scales?

Accepted Answer

A)  a higher cosmic microwave background toward the South Celestial Pole than elsewhere 
B)  that most galaxies have a peculiar motion toward the Great Attractor 
C)  a larger galaxy density toward the North Celestial Pole than toward the South Celestial Pole 
D)  all of the above

Question 7

Which of the following objects will produce the strongest gravitational lensing,all other things being equal?

Accepted Answer

A)  the hottest galaxy cluster 
B)  the most distant galaxy cluster 
C)  the most massive galaxy cluster 
D)  the galaxy cluster with the largest radius

Question 8

Imagine that Hubble discovered that the recession velocity of a galaxy increased proportionally to the square of the galaxy's distance from the Milky Way.Which of the following would NOT be true?

Accepted Answer

A)  Astronomers could calculate a galaxy's distance from its redshift. 
B)  The density of the Universe would decrease with time. 
C)  Astronomers would observe more distance galaxies as they were farther back in time. 
D)  Astronomers in any other galaxy would measure the same relationship.

Question 9

A group of galaxies with a diameter of 2 Mpc has 40 galaxies with typical velocities of 200 km/s.If the group is just a chance coincidence,how long will it last?

Accepted Answer

The answer of A group of galaxies with a diameter...

Question 10

The Hubble Deep Field was important for understanding:

Accepted Answer

A)  supernovas. 
B)  galaxies. 
C)  stellar evolution. 
D)  the cosmic web.

Exam 17: The Cosmic Web: the Large-Scale Structure of the Universe