Multiple Choice
Why are quasars rare today?
A) The Universe's expansion has spread out the quasars.
B) The black holes are too massive to be classified as quasars.
C) There is so much dust today that it obscures quasar emission.
D) Little gas is left to accrete onto supermassive black holes.
Correct Answer:

Verified
Correct Answer:
Verified
Related Questions
Q41: Two spiral galaxies collide with each other
Q42: Why are distant galaxies' spectra redshifted?
Q43: Which of the following configurations is most
Q44: What is the most likely source of
Q45: Which of the following is NOT a
Q47: Suppose that heavy elements were common in
Q48: Why were quasars most common 10 billion
Q49: Imagine that astronomers in an alternate universe
Q50: The Sloan Digital Sky Survey is most
Q51: What is the minimum scale on which