Chapter Questions
How long has it taken the light from a galaxy 1 Mpc away to reach us?
Suppose that a galaxy's $21-\mathrm{cm}$ line of atomic hydrogen is shifted to $22 \mathrm{cm}$a. What is the redshift of the galaxy?b. What is its recession velocity?
Two identical galaxies have redshifts of 0.036 and $0.072 .$ Which has the larger angular size? What is the ratio of their apparent sizes?
A galaxy has a recession velocity of $28,000 \mathrm{km} / \mathrm{sec}$. What is its distance in megaparsecs?
What is the approximate recession velocity of a galaxy that we are seeing as it looked 1 billion years ago?