mvisvitae - Here is some more from the 2003 Microsoft Encarta Encyclopedia on Wormholes:<br /><br />"Q: Do wormholes—shortcuts through time and space—exist?<br /><br />A: Isaac Newton in 1687 advanced the law of gravity, describing the strength of the force that pulls any two masses together. Albert Einstein in 1916, in his general theory of relativity, explained gravity as a warping of space. An analogy would be to put a heavy weight in the middle of your bed, causing the mattress to sag. If you then rolled a ball across the bed, its path would curve when it entered the sagging part of the mattress. You might think that the weight was pulling the ball to it by gravity. This example shows a two-dimensional surface curving into an extra dimension. Similarly, scientists describe the universe as a four-dimensional space-time, and Einstein’s theory shows how a massive object causes it to curve.<br /><br />If the weight were extremely heavy, the dent in the mattress would be very deep. A black hole is a curvature of space so extreme that nothing, not even light, can escape. Some scientists have proposed that the opposite also exists: a white hole, out of which matter comes. The question then is whether the black hole and the white hole can be connected, so that matter that goes into the black hole comes out of the white hole. We call this link a wormhole. Once you enter the black hole you are pulled inward and are eventually crushed. Wormholes can, in principle, connect two regions of space without the extreme warp of a black hole.<br /><br />In the 1980s Carl Sagan, in writing his novel Contact (later made into a major motion picture of the same name), consulted the Caltech theoretician Kip Thorne to see if a wormhole could transport his heroine from one place in the universe to another. Physicists had previously calculated that the throat connecting the two ends of a wormhole would pinch off too quickly for anything to pass through. But following Sagan’s question, Thorne and a