In astrophysics, a white hole is the opposite of a black hole. Where a black hole attracts and sucks in any nearby matter, a white hole does the opposite and pushes nearby matter away. A theory about white holes is that they act as an exit for matter sucked in by a black hole, suggesting that black holes are a type of teleporter (something that can transport objects instantly without travelling through space). The black and white holes are connected by a wormhole (see diagram).
A white hole is a thing that has been recently discovered in the field of astronomy. You will find it in mathematics if you investigate the space-time area surrounding the black hole taking away the actual star that formed the black hole. If you add any matter to the area, the white hole disappears. The person who coined the phrase, "white hole" was saying it quite literally. White holes are the exact opposites of black holes. A black holes sucks in energy and a white hole expels energy. They are polar opposites. Some scientists even believe you can make a wormhole if you connect a white hole and a black hole. Or, if you connected a white hole from the past, and connected it to a black hole today, you could theoretically create a time machine. The possibilities are endless. White holes are a bit like the Big Bang, except there probably was nothing before the Big Bang. Of course, it’s not exactly like the Big Bang, but it is similar in the way it expels energy.
However, it is very unlikely that white holes can form for a long amount of time. Once even the smallest particle of mass enters the zone of space-time that incorporates the black hole, the segment with the white hole disappears. The universe has been around long enough to take out any long-lasting white holes. However, white holes can briefly form and expel energy.
For example, in 2006, there was a gamma ray burst (known as 060614) that lasted for a whole 102 seconds. Usually, gamma ray bursts have a short duration, so it was surprising to see one lasting nearly two minutes. Everyone thought it must have been made by a supernova, but there were no supernovas that matched that particular burst.. Those who saw it didn't know what to think, and pretty much forgot about it.
Five years after the incident, people have suggested that the gamma burst was a white hole. The force and length of the outburst resonates with the idea of a white holes briefly coming into existence, then imploding on itself. Not all astronomers have accepted this theory because it is a new theory, though it is a likely possibility. Astronomers are still trying to understand white holes, and it’s possible that they will one day, but it will require new advances in astronomy and physics.
io9. io9, 25 May 2011. Web. 6 Nov. 2012. http://io9.com/5805202/mysterious-cosmic-explosion-might-be-first-ever-proof-of-white-holes
Masters, Karen. "What is a White Hole?" Curious About Astronomy. Cornell University, 26 Oct. 2003. Web. 16 Oct. 2012. <http://curious.astro.cornell.edu/question.php?number=108>.