dipper@utastro.UUCP (Debbie Byrd) (05/29/85)
An eclipse of the sun helped prove Einstein's theory of relativity. More about it -- when we come back. May 29: How the Sun Cooperates With Einstein This date in 1919 saw an early proof of Einstein's famous theory of relativity. According to relativity theory, matter and space are inseparable. You can't consider one without the other. One of the effects of this fact of nature is that matter causes space to curve. In other words, a ball of matter -- like the sun, for example -- causes space to curve AROUND it. A light ray traveling near the sun would find that the shortest distance past the sun isn't a straight line. Instead, light travels a curved line in the curved space around the sun. Einstein's theory of relativity predicted curved space. And, in May of the year 1919, a group of astronomers from England hoped to prove that curved space really exists in our universe. They traveled to Africa to observe a total eclipse of the sun. During an eclipse, the sky darkens so much that stars can be seen near the sun, in the daytime. The astronomers wanted to see whether the stars seen near the sun have the same position with respect to each other as they do when the sun is elsewhere in the sky. If Einstein's theory was correct, and light travels in curved lines in the curved space around the sun, then the stars should appear shifted -- out of place from their normal positions. And so they did. On May 29, 1919, astronomers observed this apparent shifting of stars near the sun -- caused by curved space. Since then, other observers have seen the same effect -- and Einstein's theory appears to be true. Script by Deborah Byrd. (c) Copyright 1984, 1985 McDonald Observatory, University of Texas at Austin