No one has any idea or any sort of evidence of how wormholes are formed, where they are formed, or if they even exist. All experts in the field of Gravitation and general relativity have to go on to prove their existence is theories and beliefs. A wormhole is defined as a hypothetical connection between widely separated regions of space-time. Wormholes are commonly misinterpreted as some sort of time travel, when actually they are believed to be a shortcut to make something that is very far, closer. If they do exist, experts believe them to resemble something like hurricanes would on earth, with material rotating around the outside of the wormhole. Two men that claim to be experts on wormholes are Stephan Hawking and Kip thorne, both theorists in the gravitation and general relativity fields.
Essentially a wormhole has two mouths on either end and these are connected by a pinched “throat”. The trip through these tunnels would require a significantly less time to travel and could even travel into the past. Imagine you are holding a piece of paper and have marked a point at each end. Now bend the piece of paper in half but don 't let the ends touch, if you were to travel in normal space (along the sheet of paper) the trip from one of your marks to the other would be longer than if there were a wormhole connecting the two points on the paper through the empty space between them.
Wormholes also are sometimes called “Einstein Rosen-bridges”. These would have two black holes at both entrances to the tunnel and an event horizon.
http://www.wisegeek.com/what-is-a-wormhole.htm http://curious.astro.cornell.edu/question.php?number=694 http://www.scientificamerican.com/article.cfm?id=follow-up-what-exactly-is
Cited: http://www.wisegeek.com/what-is-a-wormhole.htm http://curious.astro.cornell.edu/question.php?number=694 http://www.scientificamerican.com/article.cfm?id=follow-up-what-exactly-is http://helios.gsfc.nasa.gov/qa_sp_sl.html