Understanding Immensity

As we continue to follow the development of astronomy from Aristotle to Galileo, I am reminded our my impressions from our trip to the planetarium. Before going to the planetarium I thought that I had a sense of how large the universe was, and how microscopically small the earth was in regards to the universe. However, when we zoomed out from the earth to as far away as science can observe, I was astonished by how small are part in the universe truly is. It is hardly to believe that the earth is simply one planet in one galaxy in a universe of infinite galaxies.

These impressions allow me to understand some of what people felt as we moved away from an understanding of the galaxy as proved by the ancients to one that is almost wholly different from what they described. The movement away from a geocentric to heliocentric galaxy is similarly disturbing. Because of these shared impressions I understand their reluctance in believing in new theories as described by Copernicus and Galileo. I can only imagine what a 17th century astronomer would have felt walking on from our planetarium demonstration.