Answer Happy

Background: A key way in which we measure
distances to galaxies is through the expansion of the universe. To
use this, we have to know how fast the galaxies are moving away
from us, which we do by observing the Doppler shift of light – in
this case we will use the red hydrogen alpha absorption lines (rest
wavelength = 656.285 nm) seen in these galaxies.
a. Predict and Explain: Predict
which galaxy in the cancer
constellation is farthest away from us. Explain your
choice.
b. Calculate: Calculate the
radial velocity of at least 3 galaxies from the cancer
constellation including the one you chose in
part a. (Hint: Use the Doppler shift formula
first introduced in Chapter 5). Use these velocities to calculate
the distance to these galaxies using the Hubble law.
c. Compare: Describe whether or
not your answer makes sense by
comparing part b with your answer
to part a. If they don't agree, explain which
one has a mistake, the calculation or the prediction, and how you
can tell.
Rubric