Asri-unix.927 net.space utcsrgv!utzoo!decvax!ucbvax!C70:sri-unix!DIETZ@USC-ECL Tue Mar 9 07:39:09 1982 Background Radiation The reason we see an anisotropy in the background radiation is (they think) because our galaxy is being drawn towards the center of a supercluster of galaxies, roughly in the direction of the virgo cluster. The background radiation does not provide a prefered reference frame, because it doesn't provide ANY well defined reference frame. It expands along with the rest of the universe, so the rest velocity defined by the radiation several billion light years away is going to be a good fraction of c different from what it is here. On another topic, I read an interesting article in a recent Science about a new theory on the origin of the universe. This theory postulates that our universe is embedded in a larger space that is called a de Sitter space. Thiis space has the property that separate points move apart exponentially as time progresses. So, de Sitter space is chock full of event horizons which produce lots of Hawking radiation. This Hawking radiation causes the space to expand, generating more event horizons, etc. The space has a density of around 10^93 grams per cc and a temperature of 10^31 degrees K. Ocasionally, a phase transition in this space causes a bubble to appear. This bubble expands at the speed of light. Hawking radiation seeps in from de Sitter space making a big bang. This theory is nice: it avoids singularities at time 0, it provides for the existence of many universes (justifying the anthropic principle), it explains why the background radiation is so homogeneous (because de Sitter space is). It doesn't explain where de Sitter space comes from, though. A final note: I read somewhere about a nifty effect of relativity. Consider the view from an *accelerating* starship moving near c. For any acceleration there is a speed at which strange things happen: light emitted by a stationary observer behind the starship follows the starship forever but never quite catches it. In effect, the starship has created a black hole behind itself. This event horizon behaves just like a black hole and emits Hawking radiation. For reasonable accelerations this radiation will be very cold, however. ------- ----------------------------------------------------------------- gopher://quux.org/ conversion by John Goerzen of http://communication.ucsd.edu/A-News/ This Usenet Oldnews Archive article may be copied and distributed freely, provided: 1. There is no money collected for the text(s) of the articles. 2. The following notice remains appended to each copy: The Usenet Oldnews Archive: Compilation Copyright (C) 1981, 1996 Bruce Jones, Henry Spencer, David Wiseman.