Relativistic Ptolemaic Astronomy
If the earth is at rest at the center of the universe, the maximum diameter of the sphere of fixed stars can be calculated from Einstein’s theory of relativity. The maximum circumference of the sphere is one light day since a larger sphere would have to travel faster than the speed of light to carry the stars around the earth in 24 hours. It follows that the diameter of the universe is at most about .318 light days or a bit more than five billion miles. Since Neptune is, at its closest, 2.67 billion miles from earth and its orbit is therefore over 5 billion miles across, we can conclude that Ptolemaic astronomy has serious problems. Stay tuned.