Cosmo 101 The Schwarzschild metric

Ok so equation 4 from yesterday is the Schwarzschild metric but we won’t use all of it. That last term, the one with r^2 and phi, has to do with angles so we don’t use it much. We mostly use the first two terms. The first term describes how time changes and the second term describes how space changes. You remember that alien race that thrives around black holes. Well they are used to this and know how to measure things around a black hole. And because this is so strange to us they give us an example. Let’s say we are very close to a 5,000 meter (that’s the mass) black hole. Let’s say we start out right above the horizon (which is at 2M or 10,000 meters) and want to measure 1 meter. Now we need more information than this. There are two viewpoints we could take with this measurement. We could take the viewpoint of someone outside the influence of the black hole or we look at this from the perspective of someone right here next to the horizon. Let’s say we want to measure one meter from the viewpoint of someone outside the influence of the black hole. Now what would that one meter look like from the perspective of someone right here next to the horizon? Well if you use just the second term of the metric you calculate a distance of about 83 meters! Quite strange. Ok this is all I have time to do tonight but I’ll see if I can’t explain this more tomorrow.