All About Space
The white hole
Nobody has ever seen a 'reverse black hole' but what could they look like in theory?
White holes are thought to have a massless singularity and matter absorbed by a black hole is emitted rather than absorbed. This would mean white holes are stunningly bright.
Creating a bridge
There's a suggestion that black holes transition to white holes immediately and that a wormhole may even connect the two: the so-called Einstein-Rosen bridge.
Loss of information
With black holes, matter enters but nothing leaves. Once something – even light – reaches the event horizon there is no escape, which means all information is lost. Or does it?
Black holes are dying stars collapsing under their own weight, but what if it reaches a stage where it cannot get any smaller? An outward pressure called a quantum bounce could create a white hole.
Black hole in reverse
A white hole is the opposite of a black hole so, at the event horizon, nothing would be able to enter.