black holes and white holes

[papernuke]

i read in the wiki that black holes suck in matter, but how does a white hole work? eject it?

[edit] i read that it ejects stuff, but how does it work?

[PWrong]

As far as we know, there's no such thing. If they do exist, a white hole is either an object with negative mass, or a black hole where the flow of time is reversed.

[jinydu]

As far as I know, a white hole is a solution to Einstein's general relativity equations; similar to black holes except there is a minus sign thrown in somewhere.

But I don't think there is any experimental evidence that white holes actually physically exist.

[Rkyeun]

The white hole is the black hole viewed from the inside.
All matter and events are repelled from the horizon, unable to reach it before bouncing back.

If and only if a particle had negative energy it would also have negative mass, since E=MC^2 and the speed of light is not imaginary.
This negative mass/energy would attract all other negative masses and energies, but repel all positive masses and energies.

The universe appears to have many properties we would expect from the inside of a very large black hole.
Perhaps the white hole is the big bang and what we are perceiving as time is our gravitational repulsion from it.