Can any body tell me about White Holes.?

A white hole is the theoretical time reversal of a black hole. While a black hole acts as a vacuum, sucking up any matter that crosses the event horizon, a white hole acts as a source that ejects matter from its event horizon.

The sign of the acceleration is invariant under time reversal, so both black and white holes attract matter. The only potential difference between them is in the behavior at the horizon.

White holes cannot exist, since they violate the second law of thermodynamics.

General Relativity is time symmetric. It does not know about the second law of thermodynamics, and it does not know about which way cause and effect go. But we do.

Hi,

How do you do? Fine?

In astrophysics, a white hole is the theoretical time reversal of a black hole. While a black hole acts as a vacuum, sucking up any matter that crosses the event horizon, a white hole acts as a source that ejects matter from its event horizon. The sign of the acceleration is invariant under time reversal], so both black and white holes attract matter. The only potential difference between them is in the behavior at the horizon.

Black hole event horizons can only "suck up" matter, while white hole horizons ostensibly recede from any incoming matter at the local speed of light, so that the infalling matter never crosses. The infalling matter is then scattered and reemitted at the death of the white hole, receding to infinity after having come close to the final singular point where the white hole is destroyed. The total proper time until an infalling object encounters the singular endpoint is the same as the proper time to be swallowed by a black hole, so the white hole picture does not say what happens to the infalling matter. Ignoring the classically unpredictable emissions of the white hole, the white hole and black hole are indistinguishable for external observers.

If you want more details, goto

http://en.wikipedia.org/wiki/White_hole

Thank you

In theory they are the opposite of a black hole.

A black hole draws matter and light out of the universe a white hole ejects matter and light into the universe.

Theorectically, this is how a black hole (and consequently a white hole) can exist. For each and every action there is an equal and opposite reaction (Newton's 3rd law).

White holes are said to be the exact opposite of a black hole. unlike black holes, which suck in matter (and energy), and has virtually infinite density, and a huge mass, white holes eject matter, have zero density, and hence, zero mass but has a huge store of energy.

Proof that they dont exist --

Suppose white holes exists. they have zero mass (m=0) but huge energy(E).

as we all know, E = mc^2

so, m = E/c^2

so, 'm'(mass) is not equal to zero, as 'E' is not equal to zero.

But this contradicts the fact that

m = 0

This contradiction arises due to our wrong assumption that whit holes exist.

Hence white holes dont exist.

i think it has been proved that it does not exist practically

Do a google search for them, but add "black poles". There are several informative movies on the subject.

The opposites of black holes!

They don't exist.

white hole = big bang

They don't fade or exist ...