White Holes

[noexpert]

I was talking to a freind yesterday and he mentioned the idea that on the other side of every black hole was a white hole where the matter entering the black hole was emitted into another universe. He didn't have any evidence to support his claim, and since I had never heard this, I began searching for evidence of existance. Is there any validity or proof backing his claims? If it is true, wouldn't it make sense to have a proportionally equal number of white holes to black holes? If this is a fair assumption, where are the white holes?

[Vox]

I was talking to a freind yesterday and he mentioned the idea that on the other side of every black hole was a white hole where the matter entering the black hole was emitted into another universe. He didn't have any evidence to support his claim, and since I had never heard this, I began searching for evidence of existance. Is there any validity or proof backing his claims? If it is true, wouldn't it make sense to have a proportionally equal number of white holes to black holes? If this is a fair assumption, where are the white holes?

 

Here is one entertaining videoset concerning the topic..

 

http://www.youtube.com/watch?v=dsBAd6NYHoU&feature=related

[maddog]

I used to entertain this idea when I was studying Astrophysics in college - that maybe White Holes were in fact Quasars.

After studying recent research in to Znajek-Blandford effect and active galaxies, I find as more credible to explaining

Quasars & Blazars. However, the concept of White Holes are just that the mass goes somewhere. So if it does go into another universe then symmetry begs the some distant objects could be White Holes ? Maybe the Big Bang is such an

object ?

 

maddog

[Vox]

I used to entertain this idea when I was studying Astrophysics in college - that maybe White Holes were in fact Quasars.

After studying recent research in to Znajek-Blandford effect and active galaxies, I find as more credible to explaining

Quasars & Blazars. However, the concept of White Holes are just that the mass goes somewhere. So if it does go into another universe then symmetry begs the some distant objects could be White Holes ? Maybe the Big Bang is such an

object ?

 

maddog

 

I have "silently embraced" same kind of idea; our universe could have born this way and could give "births" to another baby universes via "black / white hole medium", which would be rather nice thought and somewhat “in line” with how life evolves. Mother Nature giving birth(s) :)

[CraigD]

White holes were a popular subject of discussion among geek teens of my generation (born ca 1960, raised on STTOS, later incarnated as ca. 1980 science students and present day scientists (the few) and professionals (the many, among them me)).

 

The basic model is black hole-wormhole-white hole, constituting in essence a simple mass-energy conveyer between practically any 2 points in spacetime. White holes are simply black holes running in reverse. The conveyer can connect points in the spacetime of a single universe, or different universes.

 

In the 1970s and '80s, this model (connecting black holes in our present and distant future with white holes in our distant past) was attractive, as it offered to explain a few vexing problems: what were the inexplicably luminous distant (and thus existing in the distant past) bodies known as quasars? why weren’t there gigantic black holes that had consumed all their neighbors? and wouldn’t black holes eventually consume everything? Connecting these two mysteries – black holes and quasars – with a wormhole, promised, on an un-detailed level, a solution.

 

Though the '80s and '90s, as detailed work showed serious problems with the idea (mainly, that while wormholes are theoretically possible, they’re inherently instable, no known mechanisms, in particular ordinary black holes formed by collapsed stars, can create them, and, naggingly, white holes by definition violate thermodynamic laws), quasars and similar ultra-luminous objects came to be widely explained as galaxies with active nuclei, it became apparent that there are gigantic black holes in the core of every galaxy, resulting in active “quasar-like” periods followed by much longer ordinary galaxy periods, and mechanism explaining why these super-massive black holes didn’t consume all their neighbors were proposed and supported, the black hole-wormhole-white hole model fell out of favor.

 

In short, there are explanations for the observed phenomena the model once explained more consistent with observation and theory, so while the physics of it is still worth exploring, the need for it has pretty much vanished.

 

So, to noexpert’s original questions ...

Is there any validity or proof backing his claims?

Yes. See the links earlier in this post. But note that, while valid, the idea isn’t considered very relevant any more.

 

If it is true, wouldn't it make sense to have a proportionally equal number of white holes to black holes?

Yes. However, since the black hole-white hole pairs aren’t required to exist in either the same place or at the same time, at any given place at any given time, they’re may not be equal numbers of them.

 

If this is a fair assumption, where are the white holes?

At one time, many thought they were quasars. See above.

[sanctus]

And if you wonder what are the mathematics behind etc. I learned about white holes in a GR-course (surprise :-) ) when looking at the Kruskal diagrams etc., see for instance:

 

here

[Qfwfq]

here

Has anybody tried carrying out the computation from the metric in terms of [imath]dV[/imath] and [imath]dU[/imath] to the usual expression in the Schwartzschild coordinates, in that wiki? In principle it is a straightforward thing using the Jacobian matrix but the coefficient of [imath]dr^2[/imath] doesn't seem to turn out right. Instead of the familiar term, I get:

 

[math]\left(\frac{r^2}{4G^2M^2}-\frac{r}{2GM}\right)^{-1}[/math]

 

No treatment of Kruskal coordinates has ever completely matched up to me, including his original publication.