8 Things You've Always Wanted To Know About Black Holes

3. White Holes

So, according to Hawking, black holes slowly evaporate away, but they could also have a slightly more explosive end.

Everybody knows that science is all about balance - for every action, there is an equal and opposite reaction and all that - so it stands to reason that black holes should have an opposite: White holes.

White holes are a sort of mathematical plaything that only exist in the theoretical world. The general idea is that, whereas a black hole pulls matter in and nothing can escape it, a white hole fires matter out, but nothing can enter it.

They're generally thought to be a virtual impossibility, and they would be incredibly unstable, and yet scientists keep cropping up claiming to have found them.

There are some who reckon that some of the brilliantly bright objects at the centre of galaxies are not, as previously thought, supermassive black holes, but supermassive white holes, spewing out matter and radiation.

Back in 2006, NASA detected an enormous gamma ray burst. These are usually associated with supernovae or star formation, however, when the burst was over, there was nothing left over to indicate that it was either. Some scientists reckon that they may have witnessed a white hole bursting into life.

Some take white holes one step even further by suggesting that they're basically the "other end" of a black hole connected by a wormhole. That would certainly explain where all that matter goes.