Black Holes.

Black holes are regions in space that have so much mass, nearby objects and even light can't escape its gravitational pull. Black holes are thought to form from heavy stars. When these stars end their lives in a supernova, their cores collapse and gravity wins out over any other force that might be able to hold the star up. (http://design.lbl.gov/education/blackholes/, 1/15/06) Black holes cannot be seen because there is no light …

…past, so that you could travel back in time by going through it. But even if a wormhole existed it would not be stable at all and there would be tons of radiation that would fry you as you traveled through it (http://cosmology.berkeley.edu/Education/BHfaq.html, 1/15/06) I have only known the science fiction part of black holes and have enjoyed the opportunity to find out the truth and possibilities of black holes.