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Double Pulsar Discovered
jabberjaw writes "Nature is reporting that a set of two pulsars could be emitting gravitational waves. Einstein predicted the existence of gravitational waves in his general theory of relativity, but a gravitational wave has yet to be detected. Find out more about gravitational waves and pulsars at Eric Weisstein's World of Physics."
Just on an intuitive level, at least. Gravity is a lot like electro-magnetism, in that it produces it's effects invisibly. That, to me at least, implies some method of energy transfer. Waves seem a reasonable enough explanation. I wonder though, if the same wave/particle duality will be observed as we see in photons. Cool stuff.
How fast is gravity?
If the sun went poof, how long would it take for Earth to go off into space? 8 minutes or as soon as it happened?
The answer is a resounding...we dunno!
We have determined that it is at least 2x10^8 m/s, however, it may be as much as 3.6x10^8 (faster than light). We honestly don't know. I'm pretty sure I heard my quantum mecanics professor at the University of Arizona mention something about Einstein's theories requiring light and gravity to equal in speed, but I'm an aerospace engineer, not a quantum physicist. If they do equal...if the sun were to disappear, we would see the light of the sun and still be fine orbit wise for about 8 minutes. Kinda funny to think about.
As for the faster-than-light communications, we could do that with tangled photons. Einstein was troubled by the fact that quantum entanglment causes an instantaneous change across a large distance. It's been used in a large number of sci-fi novels, including Orson Scott Cards Ender's Game series of books.