Seeing black holes were also speculation at first, scientists are now considering the existence of its ‘opposite’ in space…

We know that black holes suck all matter, including light and time into its centre. The matter vanishes as if into a bottomless pit – but where does it actually go? Enter white holes.

Scientists are suggesting that the matter will pop out elsewhere in the universe – or even in an entirely different universe. The point at which the matter re-emerges in the other universe would be a white hole.

This passage of matter would not be a one-way street. Matter would also leave the other universe through black holes and appear in ours through white holes. Thus the flow of matter between the two universes would be kept in balance. It is essentially the mathematical representation of a black hole but reversed.

Evidence for the white hole could be found in the huge amount of energy – cosmic rays, X rays, infrared radiation – that is apparently coming from distant quasars and from the centres of galaxies. The output seems to be greater than can be accounted for by the known physical processes.

But everything is still up for debate until somebody accidentally slips down a black hole and then manages to find his way back home again…