Exam 21: The Expanding Universe

The COBE and WMAP satellites detected fluctuations in the CMB.On average, how big were these fluctuations, and what do they that tell us about the universe at a redshift of z = 1,000?

If we lived in a galaxy 1 billion light-years from our own, what would we see?

It is possible for a galaxy to have an apparent velocity greater than the speed of light.This means that the galaxy

The apparent recessional velocities of galaxies at large distances are due mainly to

The existence of the cosmic background radiation tells us that the early universe was

If a scientist in the distant Andromeda Galaxy studies the hydrogen gas in that galaxy, they will measure ________ what a scientist in our galaxy would measure, studying hydrogen gas In the Milky Way.

The oldest photons we detect in the universe come from

If the distance of a galaxy at a redshift z = 0.05 is 220 Mpc, how many years back into the past are we looking when we observe this galaxy?

In the early 1960s, physicists Penzias and Wilson detected a persistent noise at a wavelength of about 1 mm in their radio telescope that came from all directions in the sky due to

The CMB is a snapshot of the radiation in the universe at a redshift of z 1,000 when the universe was about

If the Hubble constant were equal to 50 km/s/Mpc, what would the approximate age of the universe (the Hubble time) be, assuming that the expansion rate has stayed approximately constant over time? Note that 1 Mpc = 3.086 * 10¹⁹ km and 1 year = 3.154 * 10⁷ s.

If you measured the distances and recessional velocities for a sample of galaxies and plotted the data to get the figure shown below, what value would you derive for the Hubble constant?

If the distance of a galaxy is 5 Mpc, what is its recessional velocity if the Hubble constant is 70 km/s/Mpc?

Distant galaxies we can see today with a redshift of z 6 emitted their light when the universe was

Galaxy peculiar velocities are typically about 300 km/s.How far away do you have to look in order to see recessional velocities that are 10 times this peculiar velocity? Note that the Hubble constant has a value of 70 km/s/Mpc.

Explain how the figure below shows evidence supporting the Big Bang theory.

Why did Big Bang nucleosynthesis only produce elements less massive than beryllium?

Briefly explain how an accurate determination of Hubble constant has improved our understanding of cosmology.