# Black holes as gateway to other parts of universe **URL:** \ **Category:** Factual Questions\ **Created:** [September 11, 2000, 8:49pm UTC](https://boards.straightdope.com/t/black-holes-as-gateway-to-other-parts-of-universe/32815 "2000-09-11T20:49:06Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![toadspittle](https://avatars.discourse-cdn.com/v4/letter/t/c0e974/32.png) [@toadspittle](https://boards.straightdope.com/u/toadspittle)\ **Post date:** [September 11, 2000, 8:49pm UTC](https://boards.straightdope.com/t/black-holes-as-gateway-to-other-parts-of-universe/32815/1 "2000-09-11T20:49:06Z")
I’ve never seen a reasonable explanation of how this could possibly work–it seems to be more of a gimmick that hack sci-fi writers (as opposed to good ones) employ b/c they think it’s cool. Hence, I was disturbed to see the concept of black holes as a gateway to other parts of the universe used in the new Hayden Planetarium’s (American Museum of Natural History, NYC) Space Show. Is there any reason to believe that traveling beyond a black hole’s event horizon would get you anywhere except dead and compressed into an infinitely small point? ---
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [September 11, 2000, 9:22pm UTC](https://boards.straightdope.com/t/black-holes-as-gateway-to-other-parts-of-universe/32815/2 "2000-09-11T21:22:28Z")
Dead and smushed to a point is pretty much what you could expect and I think what most reputable scientists would go with. Of course, space gets funky in a place where it wraps back in on itself and gravity is so powerful not even light can escape. If anywhere in the universe can be weird enough to poke into other universes or other parts of our universe then I’d say a black hole is a good place to start looking. Of course, no one we ever sent in would be able to come back and tell us what coolness lies on the other side either (assuming they weren’t simply squished out of existence). ---
**Author:** ![Kyberneticist](https://avatars.discourse-cdn.com/v4/letter/k/dc4da7/32.png) [@Kyberneticist](https://boards.straightdope.com/u/Kyberneticist)\ **Post date:** [September 11, 2000, 9:45pm UTC](https://boards.straightdope.com/t/black-holes-as-gateway-to-other-parts-of-universe/32815/3 "2000-09-11T21:45:57Z")
I’ve actually read a book claiming to be a proposal for human exploration of the universe by creating a black hole nearby. (first, build a bunch of ships to collect free-floating hydrogen) There were a lot of complex graphs and math, and I really couldn’t tell you if it had any accurate basis. It seemed like it required entering a spinning black hole sideways? That being said, the main reason I’m responding is a question about the whole singularity business. I’ve read a recent dumbed-down-for-us-laymen New Scientist article which stated physicists didn’t like the infinities at the center of black holes, and were searching around for theories to explain these fringes of Einsteinian physics. True? ---
**Author:** ![Kyberneticist](https://avatars.discourse-cdn.com/v4/letter/k/dc4da7/32.png) [@Kyberneticist](https://boards.straightdope.com/u/Kyberneticist)\ **Post date:** [September 11, 2000, 9:48pm UTC](https://boards.straightdope.com/t/black-holes-as-gateway-to-other-parts-of-universe/32815/4 "2000-09-11T21:48:15Z")
I’ve been reading the links here: [http://dmoz.org/Science/Physics/Relativity/Black\_Holes/](http://dmoz.org/Science/Physics/Relativity/Black_Holes/) There are some good ones, but I’m not going to copy them all. 🙂 ---
**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\ **Post date:** [September 11, 2000, 10:43pm UTC](https://boards.straightdope.com/t/black-holes-as-gateway-to-other-parts-of-universe/32815/5 "2000-09-11T22:43:54Z")
the theory about travel via a black hole depends on white holes being real. a white hole would bee the other end of a black hole. all matter sucked into a black hole would be spitted out the corrosponding white hole. I don’t think any scientist actually think a white hole exists. also I don’t believe matter is actually compressed to a single point, no way to prove it - unless we can calculate the mass of a neutron star and find that it actually has a black hole in the middle but the star’s matter is beyond the border of the black hole ---
**Author:** ![darkcool](https://avatars.discourse-cdn.com/v4/letter/d/5f8ce5/32.png) [@darkcool](https://boards.straightdope.com/u/darkcool)\ **Post date:** [September 12, 2000, 12:43am UTC](https://boards.straightdope.com/t/black-holes-as-gateway-to-other-parts-of-universe/32815/6 "2000-09-12T00:43:16Z")
A lot depends on the shape of the universe. If, for example, the universe is saddle shaped one could imagine that if a black hole occured on the bottom of one ‘side’ of the saddle, it might well push it’s way through to the other ‘side’. Regardless, I agree w/ k2dave that it would require the existence of white holes. But maybe not… ---
**Author:** ![Alphagene](https://avatars.discourse-cdn.com/v4/letter/a/8e7dd6/32.png) [@Alphagene](https://boards.straightdope.com/u/Alphagene)\ **Post date:** [September 12, 2000, 12:55am UTC](https://boards.straightdope.com/t/black-holes-as-gateway-to-other-parts-of-universe/32815/7 "2000-09-12T00:55:38Z")
> [@](#): > > \*Originally posted by toadspittle \* > **I’ve never seen a reasonable explanation of how this could possibly work–it seems to be more of a gimmick that hack sci-fi writers (as opposed to good ones) employ b/c they think it’s cool.** Quoting from page 164 of Stephen Hawking’s [_A Brief History of Time_](http://www.amazon.com/exec/obidos/ASIN/0553380168/o/qid=968719768/sr=8-1/ref=aps_sr_b_1_3/002-1443754-3752015) > [@](#): > > The idea of wormholes between different regions of space was not an invention of science fiction writers but came from a very respectable source. > > In 1935, Einstein and Nathan Rosen wrote a paper in which they showed that general relativity allowed what they called “bridges”, but which are now known as wormholes. The Einstein-Rosen bridges didn’t last long enough for a spaceship to get through: the ship would run into a singularity as the wormhole pinched off. However, it has been suggested that it might be possible for an advanced civilization to keep a wormhole open. ---
**Author:** ![Lemur866](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lemur866/32/434_2.png) [@Lemur866](https://boards.straightdope.com/u/Lemur866)\ **Post date:** [September 12, 2000, 1:23am UTC](https://boards.straightdope.com/t/black-holes-as-gateway-to-other-parts-of-universe/32815/8 "2000-09-12T01:23:35Z")
Right, we can create wormholes but we need to find stuff with negative mass. It seems a little scarce around these parts…I seem to recall (perhaps it was in The Physics of Star Trek) that keeping a 10m wormhole open would require the energy output of all the suns in our galaxy. Anyway, all these wormholes and space warps require googolplexic amounts of energy and exotic matter. ---
**Author:** ![Lumpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lumpy/32/446_2.png) [@Lumpy](https://boards.straightdope.com/u/Lumpy)\ **Post date:** [September 12, 2000, 3:36am UTC](https://boards.straightdope.com/t/black-holes-as-gateway-to-other-parts-of-universe/32815/9 "2000-09-12T03:36:14Z")
“It used to be said that Nature abhors a vacuum. Now it seems as if Nature abhors anything that would make faster-than-light travel possible”. -me. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [September 12, 2000, 8:18pm UTC](https://boards.straightdope.com/t/black-holes-as-gateway-to-other-parts-of-universe/32815/10 "2000-09-12T20:18:48Z")
There probably are wormholes, and there may even (possibly) be usable wormholes. However, they are not black hole/white hole pairs. The problem is basically that, were there white holes anywhere within several gigaparsecs, we’d see them… And we don’t. On the other hand, there’s plenty of black holes in that same radius. Where do they all empty out? As to what’s inside a black hole, a point mass or whatever, all we can say is that the mass is spherically symmetric. Beyond that, all bets are off. ---
**Author:** ![Kyberneticist](https://avatars.discourse-cdn.com/v4/letter/k/dc4da7/32.png) [@Kyberneticist](https://boards.straightdope.com/u/Kyberneticist)\ **Post date:** [September 12, 2000, 8:35pm UTC](https://boards.straightdope.com/t/black-holes-as-gateway-to-other-parts-of-universe/32815/11 "2000-09-12T20:35:40Z")
I’ve seen speculation that quasars might be white holes. Of course, the most common explanation for quasars is that they are the massive amounts of energy released by matter spiraling into a supermassive black hole. ---
**Author:** ![Kyberneticist](https://avatars.discourse-cdn.com/v4/letter/k/dc4da7/32.png) [@Kyberneticist](https://boards.straightdope.com/u/Kyberneticist)\ **Post date:** [September 12, 2000, 8:41pm UTC](https://boards.straightdope.com/t/black-holes-as-gateway-to-other-parts-of-universe/32815/12 "2000-09-12T20:41:28Z")
This link: [http://web.ukonline.co.uk/ad.johnson/astrnmy/bh/blakhole.htm](http://web.ukonline.co.uk/ad.johnson/astrnmy/bh/blakhole.htm) , like others on the subject, seems to suggest these speculative warping effects would occur in a spinning Kerr type black hole. So if white holes exist, they may be very rare… ---
**Author:** ![Keeve](https://avatars.discourse-cdn.com/v4/letter/k/f07891/32.png) [@Keeve](https://boards.straightdope.com/u/Keeve)\ **Post date:** [September 12, 2000, 8:42pm UTC](https://boards.straightdope.com/t/black-holes-as-gateway-to-other-parts-of-universe/32815/13 "2000-09-12T20:42:00Z")
I’ve never heard of “white holes” before. Can anyone offer an explanation of that term, preferably without using the phrase “black hole”? ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [September 12, 2000, 9:37pm UTC](https://boards.straightdope.com/t/black-holes-as-gateway-to-other-parts-of-universe/32815/14 "2000-09-12T21:37:46Z")
Well, almost all black holes are believed to be rotating to some degree, since the things they form from are generally rotating. Hawking radiation will tend to act in such a way as to reduce the rotation, but Hawking radiation is a very slow process. As to the definition of a white hole, it’s something that repells so strongly, that not even light can get in :rolleyes:. The only reason to even consider them in real physics is as a long-shot potential answer to the question “What happens to the stuff that falls down a black hole?”. For these purposes, they don’t work, and there’s not really any explanation of how they would work, so toss 'em. ---
**Author:** ![muppetsoup](https://avatars.discourse-cdn.com/v4/letter/m/aca169/32.png) [@muppetsoup](https://boards.straightdope.com/u/muppetsoup)\ **Post date:** [September 12, 2000, 9:39pm UTC](https://boards.straightdope.com/t/black-holes-as-gateway-to-other-parts-of-universe/32815/15 "2000-09-12T21:39:34Z")
> [@](#): > > \*Originally posted by Keeve \* > \*\*I’ve never heard of “white holes” before. Can anyone offer an explanation of that term, preferably without using the phrase “black hole”? \*\* What I once read was that they are the mathematical opposite of a black hole, i.e. everything a blackhole does, a white hole does the opposite. I think it’s something that on paper is allowed, but most likely not in nature. The line that comes to mind is that they are unlikely, as since they are opposites, creating a white hole would be on the level of difficulty of destroying a black hole. So there ya go. ---
**Author:** ![warmgun](https://avatars.discourse-cdn.com/v4/letter/w/ecccb3/32.png) [@warmgun](https://boards.straightdope.com/u/warmgun)\ **Post date:** [September 12, 2000, 11:38pm UTC](https://boards.straightdope.com/t/black-holes-as-gateway-to-other-parts-of-universe/32815/16 "2000-09-12T23:38:05Z")
The probable reason you don’t see white holes is that mathmatically that should not exist. Without a lot of quantum gymnastics, take darkcool’s dubious example. As mass accumulated in his black hole, it would start working its way to the other side. When it got about halfway, its mass would start distorting space on the other side. Sucking the space in towards it, so to speak,attracting matter thus creating another black-hole-in-the-making opposit the original. When the two eventually meet, gravity cancels out their respective effects. So rather than a white hole spewing out great quantities of matter, the resulting ‘worm hole’ would become a fairly stable bridge in space itself until 1. the contained matter eventually ‘leakes’ back into space at large and the bridge closes ( in the case of small BH brides or 2. if the bridge is ‘wide’ enough ( in the case of large BH bridges) it will remain stable unless another black hole were to form within it, of course, causing it to collapse. ---
**Author:** ![PerfectDark](https://avatars.discourse-cdn.com/v4/letter/p/ebca7d/32.png) [@PerfectDark](https://boards.straightdope.com/u/PerfectDark)\ **Post date:** [September 13, 2000, 10:51am UTC](https://boards.straightdope.com/t/black-holes-as-gateway-to-other-parts-of-universe/32815/17 "2000-09-13T10:51:41Z")
I have always wondered what would happen to matter in the bridge if both ends of the wormhole were closed at the same time. Would it be sucked outside our universe?? Would it be destroyed, isn’t this against the conservation of energy? Also a black hole couldn’t possibly have an infinite density because it’s inertia would be infinite and couldn’t be moved by another mass (another star perhaps) and the gravitational potential energy would be destroyed once the star entered the huge gravity well. Also do gravity waves interact with each other or with large or dense masses such as black holes? Or do they act like electro-magnetic waves and pass right through each other?? Does light cause a gravity wave?? What causes light surface-pressure if light has no mass??? Could this be caused by the gravity waves caused by the light? PerfectDark ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [September 13, 2000, 4:40pm UTC](https://boards.straightdope.com/t/black-holes-as-gateway-to-other-parts-of-universe/32815/18 "2000-09-13T16:40:17Z")
If a wormhole closes, you’re left with a black hole. Note that of the wormholes believed toexist, you couldn’t even get the mass into it in the first place, without it collapsing, so it’s probably moot. Gravity waves do interact, but only very weakly, since gravity is such a weak force. Large masses will affect both gravity waves and light waves, and in the same manner. Light could, conceivably, produce gravity waves, if you had a heck of a lot of it, but not to any significant degree. Light does not have rest mass, but it does have a mass equivalent to its energy and a momentum, so it can exert pressure. Inertia is proportionate to mass, not to density, and black holes definitely have finite mass, so they’re OK. ---
**Author:** ![warmgun](https://avatars.discourse-cdn.com/v4/letter/w/ecccb3/32.png) [@warmgun](https://boards.straightdope.com/u/warmgun)\ **Post date:** [September 13, 2000, 8:09pm UTC](https://boards.straightdope.com/t/black-holes-as-gateway-to-other-parts-of-universe/32815/19 "2000-09-13T20:09:39Z")
Closing a ‘worm hole’ is not like laying a board across a hole. They are caused by space distortion, so to ‘close’ one would require un-distorting space and by definition bringing the matter inside of the worm hole out. To echo Chronos, black holes do have finite mass. ---
**Author:** ![ZenBeam](https://avatars.discourse-cdn.com/v4/letter/z/3ab097/32.png) [@ZenBeam](https://boards.straightdope.com/u/ZenBeam)\ **Post date:** [September 14, 2000, 4:52pm UTC](https://boards.straightdope.com/t/black-holes-as-gateway-to-other-parts-of-universe/32815/20 "2000-09-14T16:52:44Z")
Go to [Kyberneticist’s link](http://web.ukonline.co.uk/ad.johnson/astrnmy/bh/blakhole.htm), and take a look at the figures, in particular the second figure in the section _SpaceTime Diagrams_, and the second figure in the next section, _Spinning Black Holes_. I remember seeing these figure in a book someone was reading in High School, and not uderstanding them then. Now, twenty years and a bunch of college physics classes later, I ought to be able to figure them out. So I look them over, and they look like pseudo-physics babble to me. Do they look like that to anyone else who feels they _ought_ to be able to understand them? Note: I don’t have a problem with space-time diagrams, just the description of black holes these are purporting to show. [Next page](https://boards.straightdope.com/t/black-holes-as-gateway-to-other-parts-of-universe/32815.md?page=2)