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

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

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

Why do redshift surveys require so much telescope time?

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

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?

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

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

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?

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?

The Hubble Deep Field was important for understanding: