Chapter 18, Problem 4P

Measure the lengths of the two arrows in the left and the right panels of Figure 17-5. Create a table listing the two before expansion values and the two after expansion values, list in the same table the changes in arrow lengths from before to after (that is, the change in the lengths of the arrows pointing to the two raisins). If you are the raisin from which the arrows point, formulate a general conclusion regarding the rate each raisin is moving toward or away from you and the distance to the raisin, using your data in your answer. (Hint: It will be more convenient to use the mm side of your ruler.)

Figure 17-5 An illustration of the raisin bread analogy for the expansion of the Universe As the dough rises, raisins are pushed apart with velocities proportional to distance A colony of bacteria living on any raisin will find that the redshifts of the other raisins are proportional to their distances.