The table below contains distance and recessional velocity datafor ten galaxies.

Galaxy	Distance (Mpc)	Observed Velocity (km/s)
1	42.0	2546.0
2	92.3	5964.9
3	92.7	5490.1
4	92.9	6652.7
5	93.1	5115.3
6	150.0	9800.0
7	320.0	20260.0
8	450.0	28150.0
9	553.0	34889.0
10	642.0	40536.0

1. a) Plot the ‘Hubble Diagram’ for these galaxies. This is simplya plot of the observed velocity on the y-axis and the distance onthe x-axis.

2. b) Fit a line to the data that goes through the origin of theplot (that is, where the dis- tanceandvelocityarebothzero).TheslopeofthislineistheHubbleconstant.What is the Hubble constantfor these data? NOTE: The value is not the same as the Hubbleconstant we are adopting in the text.

3. c) Calculate the redshift, ? = ∆?/?& for each galaxy. HINT:Go back to the definition of the Doppler effect in Destination 6 torecall what = ∆?/?& is equal to (or just look at question 1cabove). You will see that have the information you need in thetable above to calculate the redshift (though, strictly speaking,only for redshifts that are significantly smaller than 1.0).

4. d) Notice that galaxies 2-5 in the table are all at about thesame distance, but their ve- locities differ rather significantly.Explain what is likely happening to account for this behavior.