In this chapter we will begin our investigation of an expanding Universe. In particular, we will look at the evidence that causes scientists to think that the Universe is expanding. We will see how an...In this chapter we will begin our investigation of an expanding Universe. In particular, we will look at the evidence that causes scientists to think that the Universe is expanding. We will see how an expanding Universe implies that at some time in the past everything we see around us must have been extremely close together, and we will learn how to calculate when that was. The stretching history we see is consistent with the predictions of general relativity, our key physical theory
