Author Question: Why are there few quasars at low redshifts and at high redshifts but many at redshifts of about 2? ... (Read 102 times)

panfilo · **on:** Jul 27, 2018

Why are there few quasars at low redshifts and at high redshifts but many at redshifts of about 2?

What will be an ideal response?

Question 2

Planetary nebulae are sites of planet formation.

a. True
b. False
Indicate whether the statement is true or false

karmakat49 · **Reply #1 on:** Jul 27, 2018

Answer to Question 1

Quasars are most common with redshifts over 2 and less common with redshifts above 3 . The largest quasar redshifts are over 6, but such high-redshift quasars are rare. Evidently astronomers see few quasars at high redshifts because they are looking back to an age when the Universe was so young it had not yet formed many galaxies. At redshifts between 2 and 3, galaxies were actively growing and colliding, and quasars were about 1000 times more common than they are now.

Answer to Question 2

False