2 Light is gathered from a distant galaxy and one of the spe

2. Light is gathered from a distant galaxy and one of the spectral lines is observed at 560 nm when it should be 400 nm. The velocity of this galaxy is ________ km/s. Only enter your numerical answer below – do not include units. If your answer is negative, be certain to include a minus sign in your answer.

Answer: ____________________

3. The distance to a galaxy with a recessional velocity of 54.000 km/s is ________ Mpc. Only enter your numerical answer below – do not include units. Report your answer to 2 decimal places.

Answer: ________________________

Solution

2. 79000km/s

3. v=H₀d

d=v/H₀

d=54,000/75 (if v=54,000)

d=720 Mpc

but if v=54.000 then d=0.72 Mpc