I recently read in a book (‘Traversing the Universe through black holes’, I believe, but I cannot for the life of me remember the author) that stated that when a black hole is created, because of the symetry of the universe, it is known that a ‘white hole’ is instantly created too. Apparantly a white hole looks similar to a supernova explosion from a distance, but everything that enters a black hole travels for a few seconds through ‘quantum foam’ (where the laws of physics break down) and is then shot out of this white hole, possibly hundreds or thousands of light years away.
However, I also read in another, similar book, (‘The Last Three Minutes’, again a book that I cannot recall the author or) that it is believed that matter which enters black holes never re-enters this universe again.
Does anyone have any information on the existance of ‘white holes’, or was the original guy talking a load of codswallop?
Until we actually find a black hole and tinker with it, it’s anybody’s guess.
I’ve heard the first two theories, and there’s a third one: anything that gets sucked into a black hole gets crushed like a little tiny bug under… well… a big heavy thing.
There is no observed evidence that confirms the existence of white holes at present. Some interpretations of what black hole theory means call for them; others do not.
Some years ago, there was strong speculation that things like quasars and Seyfert galaxies (where “the core is exploding” – to oversimplify matters) were in actuality the white holes predicted. Plus there is no clear explanation of gamma ray bursters, and if anything in the observed universe equates to what one might expect of a white hole, they do.
Podkayne and The Bad Astronomer will probably be along with better information.
Doesn’t Eignstein say that black holes literally, ‘rip the fabric of spacetime’ though? And that it does this by crushing things until they’re so dense spacetime cannot hold them?
Perhaps I’m wrong, but I thought this was the mystery about black holes; for (at least) a few moments after entering one, you leave this universe entirely.
I’m not positive but I think the ‘leave this universe entirely’ bit might just be loose and not very clear speech. Since nothing can escape a black hole nothing inside of one can have any effect on our universe whatsoever beyond increasing the gravitational pull of the black hole (by adding mass). In that sense you have ‘left our universe’ insofar as you can never return to it or effect it in any way.
If the White Hole theory holds true (and we assume that a black hole spews its stuff back into this universe and not another one) then I guess the stuff that enters a black hole can escape. However, in this case I would guess that any information the original mass entering the black hole possessed would be stripped away on its journey through the black hole (except the conservation of mass/energy).
I would assume, however, that if a black hole spewed its stuff back as a white hole then a black hole would shrink…presumably pretty quickly (although that’s a guess since I really have no basis to say how fast a white hole would or should emit energy). While we may not be able to identify white holes couldn’t we watch a black hole to see if that’s the case (that it shrinks at a noticeable rate)?
Einstein’s General Theory of Relativity expounds on the idea of space and time being the same from the Special Theory of Relativity, but it goes on to include the effects of gravity. What it predicts is that when a mass roughly twice the size of our star (the sun) accumulates it will undergo a cascade compression. When this happens, the point gravity increases infinitely. No known process can stop this. However, because space-time is intertwined with gravity this cascade takes infinite time to complete. If you were to throw a radio transmitting clock into a black hole what you would receive would be an ever increasing span of time between chimes of the clock until it finally stopped due to time compression (assuming it didn’t just break due to spacial compression.)
What does it say about wormholes and white holes? They’re not impossible.
Gravity bends space itself. Light travels the shortest distance between two points…if this is along a curved surface (in this case curved into the 4[sup]th[/sup] dimension which we cannot perceive) the light appears to bend.
Take a bed sheet, stretch it taut, and place a basketball or bowling ball in the middle. Now take a felt-tip marker and draw a straight line across the sheet that goes into at least some of the dent made by the ball. Take the ball off and you’ll notice your straight line on the curved surface is actually bent. Since us mere humans caqn’t see the straight line in the 4[sup]th[/sup] dimension we see the bent line in the third dimension instead.
A black hole in by this reckoning bends space near it so completely that ther is no path, even for light, that takes it out of the black hole. Basically space curves back in on itself. Once insode the event horizon of a black hole everything evetually ends up at the singularity.
It absolutely requires new physics because what physics we know today utterly fails us at the insane energies and densities found at a singularity. Right now educated guesses are the best that can be done but it’s part of the reason you can have divergent theories where some postulate white holes and others discount them.
This may be splitting hair but besides mass, the angular momentum of a black hole is greatly effected by the stuff falling in. This I am sure of and this has fantastic effects on the way the black hole interacts with stuff ‘left in our universe.’
I guess this proves that it doesn’t leave the universe at all.
What I’m not sure though is if the charge of black hole can be felt outside. I suspect it can but welcome any thoughts on this.
This may be splitting hair but besides mass, the angular momentum of a black hole is greatly effected by the stuff falling in. This I am sure of and this has fantastic effects on the way the black hole interacts with stuff ‘left in our universe.’
I guess this proves that it doesn’t leave the universe at all.
What I’m not sure of though is if the charge of black hole can be felt outside. I suspect it can but welcome any thoughts on this.
No white holes have ever been seen. Quasars, active galaxies and Seyferts are notwhite holes; ironically, they are powered by black holes. Stuff falling in forms a flat disk called an accretion disk. As it falls in, friction within the disk heats it hugely, which is why they get so bright. So far from having matter spew out, it’s stuff falling in that powers those types of galaxies. Gamma ray bursts are looking more and more like a very special type of supernova; perhaps the merging of two neutron stars or a normal supernova with a very strong magnetic field. No one really knows yet.
Second, black holes have three properties: mass, spin and charge.
Third, the mass doesn’t make a black hole, the escape velocity does. An object is a black hole if the escape velocity is greater than or equal to the speed of light. This happens when stars with masses more than about 8 times that of the Sun explode as supernovae; the core collapses and forms a black hole.
All of this info and more can be found at Physics and Relativity FAQ. Scroll down a ways to the Black Hole section.
A lot of older astronomy books (and science textbooks) mention “white holes” as an important theory…they stopped doing that in the '70s or '80s as more mature black hole theories emerged. Matter that falls in a black hole, according to all the recent theories I’ve read, is basically destroyed by the gravitational forces associated the singularity.
Wormholes, on the other hand, are an interesting idea…but nobody’s ever proven their existance.
Great thread! One quick question though…what would happen if two black holes were to come into close proximity to each other? I mean, if nothing can escape a back hole, what would happen? Seems to me that if two stars come close enough to each other, the greater will draw off matter and energy from the lesser. So how about it?
First of all, as the esteemed Bad Astronomer mentioned, we haven’t seen any white holes. What he didn’t mention, though, is that if they existed, we would see them. A white hole would be a pretty bright object, and we know about how many black holes there are in the Universe, and if there’s one for each, that’s an awful lot of white ones, too.
Now, as to the two black holes near each other: Just like anything else with mass, they’d go into an orbit around their common center of mass. Black holes gravitate in exactly the same manner as anything else with mass, with the sole difference being that you can get closer to a BH than to anything else with the same mass. If, for instance, you replaced the Sun with a solar-mass black hole, the orbits of the planets would be entirely unchanged.
But suppose that your two holes get close enough together that their event horizons overlap. What happens then is that the two holes merge into one larger hole, and release tremendous amounts of energy in the process. The total power would dwarf even a supernova, but it’d be almost entirely in gravitational waves, so it’d be almost unnoticeable.
It’s possible that we have. A white hole, from a distance, would not look any different to a large supernova, a quasar or an exploding galaxy.
Firstly, we don’t know how many black holes there are in the universe. Even the best scientists admit that any guesses at how many are just that - guesses. Only one black hole has actually been found in the universe (unless loads have been found in the last 20 years).
Secondly, there’s only so much of the universe we can see. For all we know, our visible universe could be ringed by millions of white holes. We simply don’t yet know.
If the mass when a black hole forms pops out of a white hole, shouldn’t the black hole shrink and vanish? Otherwise, you could bring the white hole near its corresponding black hole, and let the material flowing out of the white hole fall right back into the black hole, which would just keep growing. Until it gets so big it swallows the white hole… Its own white hole… And then… Umm… :eek:
If the black hole does shrink and vanish, seeing black holes means there aren’t any white holes.
I think it would look quite different from a supernova. A supernova gets bright quickly (in a week or two) and then fades in a very predictable manner over months and years.
I suppose there might be some similarities between a quasar and a white hole, though I suspect the detailed characteristics would be different. That doesn’t rule out white holes, but as has been said, the idea of white holes has rather fallen out of favor for other reasons.
Also, there are no exploding galaxies, as far as we know. The galaxies that were once thought to be exploding (and were the inspiration for many Larry Niven stories) are now understood to be undergoing intense bursts of star formation. The vast amount of energy released in these starburst galaxies makes them look like parts of them are exploding.
Well, a black hole with a mass equivalent to the mass of the known universe would have a diameter equivalent to that of the known universe. And, of course, no light would escape from it, because the mass of the hole would keep the light moving in a more-or-less circular path, with the same diameter as the universe/hole. One would never be able to reach the edge of the hole – it would seem to be receding. Does any of this sound at all familiar?