Could Black Holes Be Portals to Other Universes?

David Shiga writes "Astronomers have identified many objects out there that they think are black holes. But could they be portals to other universes called wormholes, instead? According to a new study by a pair of physicists, we wouldn't be able to tell the difference. They have discovered that wormholes with the right shape would look identical to black holes from the outside. But while a trip into a black hole would mean certain death, a wormhole might spit you out into a parallel universe with its own stars and planets. Exotic effects from quantum physics might produce wormholes naturally from collapsing stars, one of the physicist says, and they might even be produced in future particle accelerator experiments."

Comments

Into the Unknown: The Circle

[HTH NE1]

In fact, theorists say one variety of wormhole wraps back onto itself, so that it leads not to another universe, but back to its own entrance.

I'm expecting others to beat me to referencing The Black Hole and Dr. Hans Reinhardt's line, "In, through, and beyond," or even Farscape and Rigel's bored, "Wormhole. Normal space. Wormhole." So instead, and considering slashdot's current technical problems, how about something more obscure.

Wasn't this an episode of the original The Tomorrow People, except that transit time felt like it took much longer than it really did, whereas the reality of time dilation would likely be the reverse?

Re:Into the Unknown: The Circle

[IthnkImParanoid]

Wasn't this an episode of the original The Tomorrow People, except that transit time felt like it took much longer than it really did, whereas the reality of time dilation would likely be the reverse?

That also sounds like a Steven King short story called (IIRC) The Jaunt, where teleportation to Mars was nearly instantaneous for outside observers, but if you were awake when you traveled your consciousness perceived the transit time as nearly infinite.

Re:Into the Unknown: The Circle

[Pollardito]

a wormhole that's a loop and leads back to itself reminds me more of European Vacation: "Hey look kids, there's Big Ben, and there's Parliament."

Re:Into the Unknown: The Circle

[rasputin465]

Black holes are where god divided by zero

I can only imagine

[wmwilson01]

"Err... Captain, are you *sure* that's a wormhole and not just a blackhole?" "Shush! If there's one thing I learned at Starfleet Academy it's the difference between a wormhole and a

Re:I can only imagine

[suv4x4]

"But while a trip into a black hole would mean certain death, a wormhole might spit you out into a parallel universe with its own stars and planets."

Err.. something's gotta be wrong here. First of all, let's face it: you'll be dead never mind if it's a portal or not. The fact that my energy will somehow exit on the other end offers little comfort, knowing that to be alive, I need to also have my structure preserved.

The idea about wormholes was introduced when experimenting (mathematically) what would the opposite of a black hole be, using just the known laws of physics and math.

The thing is, most objects in the universe have their exact opposite version (the most trivial example being matter and antimatter), so scientists thought the same might apply to black holes. Lots of new object classes were prophesied this way.

Thus, the concept of a while hole was born, which is not like a black hole at all: instead of only sucking in matter and energy (ignoring Hawking radiation for a moment), white holes can only emit matter and energy. Naturally, this posed the question, where is this matter coming from? And the obvious answer was: from a blackhole that's elsewhere. So a wormhole is in fact the whole mechanism where a black hole is tied to a white hole, and whatever falls in a black hole, comes out the white hole.

So I don't know what those scientists are talking about, but either is the article written very poorly, or the term "wormhole" is being used totally inappropriately here.

A "wormhole" can't look the same as "blackhole". It's like saying that a computer (the whole thing) may look to a keyboard (the input only). A wormhole isn't some sci-fi generic space warp where you put your ship to go to Degoba.

And you're definitely dead either way, but if you're brave, up on the next shuttle and go try it, in case a wormhole is passing by.

Going into confusion...

[bitRAKE]

What would a blackhole going through a wormhole look like?

(Or is that when the 503 error happens?)

Re:Going into confusion...

[rs79]

"What would a blackhole going through a wormhole look like?"

Utah.

Life imitates art, doesn't it?

[semifamous]

I always knew that black holes were portals.
I mean, isn't this basic science? You go in one side and you come out the other.

It's kinda like Pac-Man, right?

Wow, what an original idea!

[caywen]

I simply never thought of black holes and wormholes that way. Going to another universe/dimension/time/etc - gosh that's something that I don't think even science fiction has considered. I always thought they were just kind of, um, holes or something.

Re:Wow, what an original idea!

[Jarjarthejedi]

Hmm...seems more like a Truck to me...I mean, you get in and may or may not come out...reminds of hitchhiking and it's even dependant on what kind of effects you have on you!

Universal gravity

[Anonymous Coward]

A chemistry teacher of mine in high school (early 90's) of mine had a big, long lecture about the universe and built it all up from subatomic particles and ended with the vastness of space. It was his Xmas gift for his classes every year, and we loved it. Well at least those with half a brain did.

Anyway, his twist at the end resembled this article. He said that everything in the universe has gravity. Well, if everything has gravity, then the universe itself has a gravitational pull. Eventually the mass of the universe would be such that any light trying to escape it would be pulled back inside, which would make the universe appear to be black hole from anyone on the outside looking in...

Re:Universal gravity

[Ambitwistor]

Well, if everything has gravity, then the universe itself has a gravitational pull. Eventually the mass of the universe would be such that any light trying to escape it would be pulled back inside, which would make the universe appear to be black hole from anyone on the outside looking in... It sounds like your teacher may have had the misconception that the universe is an expanding sphere, with stars and galaxies on the inside, and a void outside into which the matter expands.

That's not how Big Bang cosmology works, however. In that theory, all of space is filled with matter, and space itself expands, carrying the matter with it. There is no "edge".

Consequently, it doesn't make much sense to speak of light trying to "escape" the universe, since the universe has no boundary. That's why it's problematic to speak of the whole universe as a "black hole".

For a related FAQ, see here.

Re:Universal gravity

[Ambitwistor]

Which is actually something that's been bothering me since I thought of it: I feel like there's a tendency in cosmology to forget that time is also a dimension, and that the big bang is an expansion not of SPACE, but of SPACE-TIME. No. "Expansion" refers to space, specifically an increase of spatial distances over time.

However, it is true that spacetime is curved.

So if space and time is expanding, how can it be something that is taking time? How can time be expanding along a timeline? That's one of many reasons why nobody speaks of "spacetime" expanding. It doesn't have a meaningful definition.

This is an issue of semantics, not of physics.

I get the feeling, in all these many multi-dimensional theories of our universe, that it's a mistake to think about "time" as being somehow distinct and "special" as a dimension. Geometrically, it is distinct and special. It's because the geometry of spacetime is described by a modified Pythagorean theorem (a Lorentzian metric), in which the sign of a (squared) timelike displacement is opposite to that of a spacelike displacement.

Space and time are unified into spacetime, but that doesn't mean that space and time are the same thing. Rather, it means that what is "space" to one observer may be a mix of "space and time" to another. However, all observers agree on whether a direction is overall timelike or overall spacelike.

But in that case, does time play some special role in the big bang? In general relativity, time isn't even defined at the Big Bang; the geometry of spacetime breaks down. In a replacement theory of quantum gravity, who knows ...

Just like putting

[geekoid]

a portable hole into a bag of holding!

what would happen on the other side?

[radarsat1]

Well, I'm no physicist, but it seems reasonable to me to assume that if the formation of black holes can rip through to another universe, or perhaps another part of a curved universe, then an event would take place on the other side: the formation of a matching wormhole mouth.

We have to assume that if blackholes can form in our universe, then they can form in the "other" universe. So we would be seeing the spontaneous formation of black holes occurring here that are the result of collapsing stars on the other side.

So my question is, what does this event look like from the perspective of the other side, and have we observed it happening here?

Re:what would happen on the other side?

[radarsat1]

An additional question comes to mind: If black holes have an event horizon beyond which no matter can return, and there is a wormhole with a black hole on each side, then if you went into the black hole and try to get out the other side, you'd find that you're behind the other black hole's event horizon and are unable to escape. So... you'd be in a tunnel from which there is no escape. So... you'd stick in a wormhole... which doesn't seem all that different from a black hole... what was the point of this thought experiment again?

Perhaps wormholes just don't exist then.

I think the thing that differentiates worm holes from black holes is that they DON'T shrink to a singularity, but instead attach to a hole on the other side of the universe through a tunnel that has a finite radius. So they're not the same thing... the difference between having a singularity and NOT having a singularity is pretty staggering. Is the point of the article just trying to say that wormholes have an event horizon?

Re:what would happen on the other side?

[maraist]

I can't remember the original source.. But in the book 'The God Delusion', there were references to several official big-bang theories.. One of which was the hypothesis that black-holes represent spontaneous synthesis of isolated sub-universes. Where information doesn't leak-back-in to the source universe.. Each sub-universe could have potentially deviant quantium properties such that the mass, charge, force-strenght, etc of various quantum particles would differ ever so slightly.. That by this process, universes actually evolve - ones that have unstable quantum characteristics quickly devolve (perhaps expanding too quickly, or collapsing back into itself, etc).. By virtue of the fact that our universe survived long enough to spawn life, this would represent a successful set of quantum characteristics - though there may be alternate sister, parental or child universes with more ideal states.

But, it stands to reason that such evolutionary universes don't allow cross-talk, that you wouldn't be able to worm-hole back into your neighboring universe. If nothing else, the difference in quantum properties would cause your physical person to become highly unstable.

Of course it's still conceivable that the sister universes have identical properties (that there is only one set), that perhaps only the differing ratio of particles (such as the over-abundance of matter v.s. antimatter in our universe). To which we may still survive in the alternate universe - just have to watch out for our alter ego.

Though, to me, an identical universe, or even a sister universe is kind of boring to me.. Just seems like infinity times k. whop-ti-doo. The only interesting cases to me, are the evolving universes or the true singularity of our universe.

Let's throw the hardened convicts in there

[atari2600]

You know, the really really bad guys. Give them a ship with food, guns and other building blocks for "civilization". If they make it, well we win. If they don't, well too bad but that relieves the load on prisons. What? It worked for Australia didn't it? Ok laugh now - that was supposed to be funny.

Hmmm, come to think about it; not a bad idea at all.

Oh, well, that's different

[Deadstick]

But while a trip into a black hole would mean certain death, a wormhole might spit you out into a parallel universe

...dead.

rj

The paper

[Ambitwistor]

New Scientist has a link to the paper, which is small and off to the side and easily overlooked (and does not make clear that the whole paper can be accessed, not just the abstract). The paper is here for anyone who may have missed it.

No event horizon

[suv4x4]

The article claims, that unlike a black hole, a "wormhole" (in the sense they explain it) has no event horizon. If it has no event horizon, it means light can escape it.

So it wouldn't look like a black hole AT ALL. I call bullshit on the whole article.

Re:No event horizon

[Ambitwistor]

So it wouldn't look like a black hole AT ALL. I call bullshit on the whole article. I think you may want to take a more informed look at their claims before making such strong statements.

The authors propose a wormhole constructed such that light takes so long to escape from its mouth, it's effectively indistinguishable from a black hole, because nobody can realistically wait long enough to see anything come out of it.

They write,

An immediate consequence of the metric (2.1) is that time in the throat is extremely slow from the point of view of a distant observer. Indeed, they are related by lambda, [...] The throat thus mimics what happens at the event horizon of a black hole where time is "frozen" [we recall that the old name (especially in Russia) for a black hole was a "frozen star"]. The only difference from an actual horizon is that time does not completely stop in the throat: if an observer makes observations during a time of order GM/lambda he or she will resolve the processes happening in the throat and thus be able to distinguish a wormhole from a black hole. Reciprocally, this preliminary remark suggests that if an observer only looks at a wormhole during a finite time he or she might not be able to distinguish it from a black hole. We shall see below, in several examples, that this is indeed the case, even for phenomena that are usually considered as characteristically linked to the presence of an horizon (such as no-hair properties, or dissipative properties). However, we shall see that the observing time span needed to distinguish a wormhole from a black hole is not GM/lambda, as suggested by the above naive argument, but rather GM/ln(1/lambda).

Falling into a black hole is not certain death.

[JesseL]

It depends on the size of the black hole. Small ones will have sharper gravitational gradients that will result in tidal forces that could inflict serious entropy on you, but a large enough black hole could have a surface gravity less than earth and much less significant tidal forces.

Re:We could

[Dr. Eggman]

Bad idea. I fear the consequences of allowing the two most dense entities in the universe to cross paths:

Try to imagine all life as you know it stopping instantaneously and every molecule in your body exploding at the speed of light.

Re:Logical contradiction

[illegalcortex]

You're not just splitting hairs, you're assuming that a word is simply a collection of roots (Latin or otherwise) and it has a fixed and unchanging meaning derived from them.

That's really not the case with language. It's ESPECIALLY not the case with scientific language.

You might also notice that what you posted isn't the definition of universe, it's a definition of universe. Another from the same page: a world or sphere in which something exists or prevails. This is much more applicable to our usage of universe to mean the current cosmology we understand.

I know it makes some people who crave order and stability mad, but language is created, molded, abused and transformed by the speakers and writers with little remorse for whose feelings may be hurt.

You misunderstand

[Fallen Seraph]

Black -> White holes was an older theory. That's NOT the theory of wormholes. A Black/White hole system is one way. Matter enters a Black Hole and exits a White Hole. Both are continually connected to one another. Additionally, your history is off, because it wasn't just a thought experiment questioning an opposite. It was an attempt to answer the question "Where does the matter entering a black hole go?" The logical answer (physics aside) would have been a white hole.

Wormhole theory is different. The theory of a wormhole is that under certain conditions, the warping of space-time can be so extreme that two massive distortions can connect to one another. Essentially, that the singularities of 2 black holes touch, and open up a tunnel through space-time, which is shorter than the trip through normal space-time. These connections can last for a single instant or longer, but they are not considered to be permanent, and are, hypothetically, rarely stable last I read.

Whether they connect to other points (black holes) within our own Universe, or within other Universes depends largely on the shape of the Universe and if multi-verse theory is even real. The shape being the major determining factor in a great deal of such very theoretical physics.

Finally, a wormhole looping back on itself would not longer join spans of space, but instead, spans of time. It would connect to it's past or future self, because doing so would involve looping, and a common theory is that the more a wormhole loops, the more it displaces itself within time.


Who knew reading a Brief History of Time so many years ago would eventually pay off? :P

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