Wormholes Unstable (BBC)

An anonymous reader writes that "The BBC reports on recent theoretical physics research showing that wormholes may not be very useful for space or time travel. Wormholes with smooth or classical spacetimes appear to be unstable and fall apart quickly. Too bad for budding time travelers and space explorers!"

Comments

Duh

[Xshare]

Duh, that's why they have the dampener things on the stargate.

Re:Duh

[metlin]

Yeah, but where are you gonna get the damn Naquadah from, huh?

Huh!?! P3x742!?

Re:Duh

[eofpi]

Or at least the 38-minute limit.

Oh No!

[Bob McCown]

A completely theoretical and as-yet-to-be-discovered phenominon is unstable, and unusable for transportation? Say it aint so!

Re:Oh No!

[MarkGriz]

A completely theoretical and as-yet-to-be-discovered phenominon is unstable, and unusable for transportation? Say it aint so

Dammit, and just as my theoretical nanotube space elevator was almost complete.

Re:Oh No!

[jtbauki]

Dammit, and just as my theoretical nanotube space elevator was almost complete.

Were you going to take that elevator to your theoretical girlfriend?

Re:Oh No!

[MarkGriz]

Were you going to take that elevator to your theoretical girlfriend?

Yes, but my mom wouldn't let me cut a hole in the basement ceiling.

Re:Oh No!

[borroff]

I can just see the dialog now:

Captain: I'll give you a ride on my space elevator if you show me your wormhole.

Green-skinned lady-of-casual-virtue: Well if it wasn't a nanotube, maybe you'd get somewhere! It takes exotic matter to keep my wormhole from collapsing.

hmmm

[justforaday]

This work obviously needs to be run by a futurologist for a second opinion.

Escape

[quintiusc]

According to the article theoretically a wormhole that opens to a random place/time is still stable. It would make a great getaway. "You don't know where I'm going and neither do I. *poof*"

Of course they're unstable.

[allanc]

That's why the artificially-created stable one near the Deep Space Nine station was so strategically valuable.

We knew that

[AndroidCat]

Either you need the Prophets/wormhole aliens living in the wormhole, or you can only hold the StarGate open for a limited amount of time.

Elementary sci-fi!

Screwed up plans

[Hoi Polloi]

Well there goes my plans for the summer!

Well...

[catdevnull]

I suppose this makes it more like the "improbability" drive now, doesn't it?

You wouldn't have to be in a wormhole very long to travel somewhere (sometime) else--as long as you're not counting on the return trip.

I felt a disturbance in the force...

[Anonymous Coward]

"I felt a disturbance in the force. It was as if millions of sci-fi fan boys suddenly lost their erections and started crying."

You know what's bullshit

[Adult film producer]

That they made jodie foster wear that goofy outfit when she travelled through the wormhole.. come on, I'd like to think todays audiences are mature enough to handle a little bit of nudity, seeing her hotly oiled up and sleek body slips through the cosmic threshold shouldn't dismay anyone.

I'm going with her on the next trip, in the raw baby!

Re:You know what's bullshit

[Colin Smith]

I suspect you may not be her type.

This explains the low-attendance ...

[Kaemaril]

Well, no wonder the time-travel convention was a bust :)

Still might be useful having small ones

[Smiffa2001]

The real challenge was in explaining how to engineer wormholes big enough to be of practical use.

Well, surely a small wormhole would enable radio transmissions through? Or would interference be a problem? Wavelength? Maybe a light-based comms-medium...?

"Frankly no engineer is going to be able to do that," said the York researcher.

And that just seems so shortsighted...

Is computational power the only thing missing?

[Glowing Fish]

From the article:

But building a wormhole with a throat radius big enough to just fit a proton would require fine-tuning to within one part in 10 to the power of 30. A human-sized wormhole would require fine-tuning to within one part in 10 to the power of 60.

"Frankly no engineer is going to be able to do that," said the York researcher.

Well, I don't know if any engineer could do that with pencil and paper, but I am sure a computer could do it. Well, I am not sure a computer could do it, but growths in computational speed and power have certainly surprised us so far...

Re:Is computational power the only thing missing?

[yotto]

Yeah, I imagine 150 years from now people joking, "10 to the power of 60 ought to be fine tuned enough for anybody."

Re:Is computational power the only thing missing?

[thermopile]

Sigh. Okay, I'll bite.

Suppose, a few years from now, individual processors can do 100 trillion floating point operations per second. And you wire up 20,000 of these nodes in parallel. And suppose each floating point operation can magically operate one of those 10 to the 60th things-that-it-needs to (TFA didn't say *what* had to be controlled to within one in 10 to the 60th).

That's still 10^34 years. Not counting leap years.

I'm not holding my breath ...

Ten years too late

[Qrlx]

Man, if only we had known that wormholes were unsafe for space travel back in 1995, we could have been spared the agony of seven seasons of Star Trek: Voyager

JANEWAY: Chakotay, take us into the wormhole.

CHAKOTY: Aye aye, Captain!

PARIS: (aside to TORRES) Heh, she said "wormhole."

*crunch*

Not true

[barcodez]

The one I was using tomorrow worked just fine, well, it did until it broke yesterday.

PHB Mining

[Shadow Wrought]

Exotic matter is repelled, rather than attracted, by gravity and is said to have negative energy - meaning it has even less than empty space.

So how long before they start mining PHB's brains for Exotic matter?

The Worm Turns

[Doc Ruby]

If wormholes allow time travel, their brevity is nearly irrelevant.

Re:This is hardly news.

[shbazjinkens]

Is it just me or do other people also find it disturbing that trekkies consider DS9 to be a reliable and reputable source of scientific information about wormholes?

Re:Heisenberg

[daeley]

It's Heisenberg all over again!

...or is it?

Re:Am I the only one...

[stlhawkeye]

It's the blind spot of psychology. There's a spot where your retina attached to your optic nerve (or whatever), and your eye can't actually see that little spot in front of you. Luckily, your other eye covers that ground. What if you close one eye? Then you can actually detect the "blind spot" but it's not straightforward. Your brains "fills in" the missing data, and there are various tricks you can play to make this happen and observe it.

What you've encountered here is akin to that phenomenon, only on a word-association level. You saw "W----s unstable" and your brain said, "WINDOWS!" This phenomenon is especially prevelent in males ages 9 through 120, who readily associate almost anything they encounter with their own genitals or breasts.

Yeah right.

[ChaosCube]

What a load of crap. I mean, if this was accurate science regarding wormholes and time travel and such, how do you explain John Titor?

Fools.

Re:This is hardly news.

[Dogtanian]

Is it just me or do other people also find it disturbing that trekkies consider DS9 to be a reliable and reputable source of scientific information about wormholes?

I agree. DS9 hasn't been on TV for years; anything you learned from that is going to be out-of-date now.

I get all *my* scientific knowledge from 'Enterprise'...

WHAT!?!? Are there no Farscape fans on /. !?!?!?

[DeadMilkman]

Not a single John Crichton commment...Just a bunch of DS9/SG1 tripe -_- Where are the REAL nerds at!

Weird

[hey!]

Speaking of wormholes, there appears to be one in Slashcode that is making comments disappear from one thread and have them appear in another, possibly in a completely different article.

Re:Am I the only one...

[Danger Stevens]

males ages 9 through 120, who readily associate almost anything they encounter with their own genitals or breasts.

As a male, I admit I spend way too much time associating things with my breasts.

All you need is PART of the wormhole

[Vitriol Angst]

The wormhole doesn't have to be stable to be useful. You could create a wormhole around a ship, and allow it to break apart behind. You could also say that rockets are unstable, because they only have a stable stream of plasma for a few feet--yet they still move the rocket.

Of course, putting limits on things that are still fiction is kind of ironic.

Re:Information Theory Hell

[dgatwood]

Actually, it isn't inconsistent at all. In Stargate, the gate disassembles matter that enters the event horizon and sends it through (presumably as a data stream, though this isn't clear) to the gate at the other end, which reassembles it. My assumption is that it isn't practical for solid matter to go through as a unit because of the size of the wormhole, but there could be other reasons. It's unclear.

It seems quite reasonable, then, for the gate systems to not attempt to handle disassembly and reassembly in opposite directions concurrently, presumably for safety reasons. One would not want to rematerialize in the middle of someone else who was in the process of dematerializing. Since there would be no reasonable mechanism for preventing someone from stepping into the event horizon at the wrong time with a bidirectional gate mechanism, the designers made it unidirectional. Seems perfectly reasonable.

That said, it should be possible to switch the direction of the gate connection while the connection is open. I can't see any valid reason for that not to be possible except while someone is in transit, as it should amount to a mode switch in software, coupled with a simple flow control mechanism.

Re:Hilarious?

[Danger Stevens]

Apparently everyone at slashdot thinks this is funny. Isn't this supposed to be BAD NEWS?

This isn't the cancellation of Star Trek, this is real space travel. And therefore less important.

Actually, it's likely much more

[jd]

I did a simple, back-of-the-envelope calculation on what it would take to keep a wormhole open.

You need to have a net negative mass, which means that your exotic matter (or energy equiv) must be equal to the mass of the object traversing the wormhole, PLUS the mass of the wormhole itself, PLUS the mass of any other particles within the wormhole, PLUS the mass equiv of the energy that the vaccuum created naturally has.

You also need to bear in mind that exotic matter is believed to have a very short half-life - about 10^-30 seconds - which means that it must be traversing the wormhole at high speed and must constantly be replaced at that rate.

But that isn't all! There is a problem with wormholes in close proximity to each other - they are unstable. And quantum-scale wormholes supposedly occur everywhere in the quantum vaccuum. So, you've got to do some fairly complex stuff to exclude other wormholes from the vicinity of the one you want.

Generating the exotic matter/energy is also a hard problem. Methods include the Casmir Effect, which requires generating fields of absolutely staggering strength to exclude all possible positive energy between two plates. The exclusion principle, combined with the requirement that a vaccuum must have a non-zero state in QM, is what forces the existance of a negative state.

So, what you need to do is basically have gigantic Casmir Effect-based exotic matter generators, which will require vastly more positive energy then the negative energy they create.

I think I figured out that you'd need to convert most of the galaxy into pure energy in order to move even a relatively small object via a wormhole over any kind of reasonable distance, once you take these additional requirements into account.

The problem is, if you are capable of collecting a galaxy together to convert it into enough energy to do this, you have sufficient technology to reach anywhere in the galaxy anyway, making the wormhole method of travel totally unnecessary. Besides which, you also get the benefit of having somewhere to go.

That's old news!

[DancesWithBlowTorch]

I've been taught that Einstein-Rosen bridges ("Wormholes") are unstable in MSc lectures. This knowledge is at least five to ten years old. I can't find the appropriate paper at the moment, but if you try this summary of Black Hole Theory, for example, it will tell you on page 25 that Wormholes are not crossable. There are similar problems with time machines ("closed timelike curves") and other strange phenomena of Quantum Cosmology: They all sound so cool at the beginning, but the closer you look, the less interesting they get.

"Negative Energy" a conceptual mistake?

[Pfhorrest]

This isn't exactly a response to your post, but more a question for this entire thread... but you seem like you may be a physicist or at least well versed enough in the mathematics thereof to be able to do "back-of-the-envelope calculations" about it, so maybe you can answer this question for me.

Why is it assumed that because something has negative mass - which I would define as "the quality of being repelled from, rather than attracted to, ordinary positive mass" - it has negative *energy*? Likewise, why is it assumed that any energy (such as vacuum energy) translates directly into positive mass?

I've always viewed it similarly to charge. Both mass and charge are a form of potential energy. An electron and a proton have the same amount of electrical potential energy as one another, only differing in the nature of that potential relative to other charges (whether it repels or attracts a positive or negative charge). But does a proton then have "positive" potential energy and an electron have "negative" potential energy? If the answer to that is no, then why does something with "negative" mass have to have "negative" energy? Is a space filled with a negative charge "less than empty vacuum"?

I'm well aware of e=mc^2 of course, and why that would lead to a negative value for e if you have a negative value for m. But given that physics traditionally deals with only positive values for m, wouldn't e=|m|c^2 (using the absolute value of m, instead of just m) return the same results for all physics thus far, dealing with positive mass, without the counterintuitive "less than nothing" idea of "negative energy" if ever we managed to produce something with negative mass?

Re:"Negative Energy" a conceptual mistake?

[jd]

I'll answer this as best as I can.

The mass/energy equivalence is actually quite important, because really mass is energy - in the early Universe, energy was all there was. What we call matter "condensed" out of that. The two are not just comparable, therefore, they really are the same stuff. Thus, E=MC^2 is true for both positive and negative masses, because negative mass must be condensed from negative energy.

(I'm not sure if that's very clear.)

Anyways, a negative charge is NOT the same as negative energy. An electron has a positive mass and will therefore convert to a positive amount of energy, and likewise if you were to "fuse" that energy, you would get an electron with it's attendent negative charge but positive mass.

Nor is antimatter the same as negative matter. Antimatter and matter are largely the same stuff, but "rotated". (Matter has 720' symmetry, so if you "rotate" matter only 360', it becomes antimatter. This is covered in Professor Hawking's Brief History Of Time.)

Negative matter has negative mass. This means that it would have negative momentum, negative gravity and all sorts of other bizare characteristics. (To give you an example, a positive massed rocket that used negatively massed fuel would fire the engines in the direction it wished to go.)

Because the forces inside a negative mass are repulsive, negative mass is highly unstable, as all the forces are trying to blast it apart. What you would want is matter that is sufficiently distributed that the repulsive force (in this case, things like gravity) are weaker than what would be attractive forces (in this case, say, the strong nuclear force, which is normally repulsive, in positive matter).

It is very unclear as to whether you could have complex atoms with a negative mass, simply because gravity and the strong nuclear force are not equal and therefore there would be a high degree of asymmetry in what would be possible.

Negative mass or negative energy is required in a stable wormhole, because it forces the throat of the wormhole to stay open. Normally, a wormhole would collapse instantaneously, whenever any positive mass or energy tried to cross it, but the negative mass/energy prevents it from doing so. Provided there is enough.

Essentially, what you are doing is creating a region of space that has such an intense repulsive force that "normal" space cannot enter into that region.

Of course, this does beg an important question - is the force so great that NOTHING can enter? If so, then such wormholes may exist almost everywhere and we'd never know, as the normal Universe would wrap round it.

Re:"Negative Energy" a conceptual mistake?

[Pfhorrest]

That was an intelligent answer, but I think you may have misunderstood the nature of my question, and as such have not entirely answered it.

I was not claiming that a negative charge was negative energy, or asking for clarification about that. I was analogizing the potential energy due to charge (electrostatic force) with the potential energy of a mass (gravity). An electron and proton, ignoring gravity, have a certain amount of potential energy relative to one another just because of their charges; that is to say, if released, they would move closer together and gain velocity, and kinetic energy. A hypothetical particle identical to an electron but with a greater charge would have *more* potential energy relative to that proton, as the attraction between them would be stronger, even though their masses are the same, so it's pretty clear that the attraction due to charge counts as "potential energy" the same as attraction due to mass.

But now, take the potential energy due to charge (again, ignoring gravity) of two electrons. As the charge of a proton and and an electron are equal but opposite, is the potential energy between them (ignoring gravity) not the same? Or would you say an electron has a negative potential energy (even considering gravity now) to another electron, since they would repel one another? In that case, the "positive" and "negative" differences of energy seem only to apply to potential, not kinetic, energy, and refer only to the direction of the force applied relative to another body.

Furthermore, in the case of electrical charges, that attraction or repulsion is relative to not only the strength but the sign of charge of another body, in which case, how do you know that this exotic matter with negative mass, while it may have negative (repulsive) potential energy to positive mass, does not have positive (attractive) potential energy to other exotic matter? After all, we know that likes attract with positive masses, so it stands to reason that likes would attract with negative masses as well.

Has anyone ever made or discovered particles of this "exotic matter" and measured the relative attraction of them to each other? I imagine for the extremely short lifespans you claim for it, it would be difficult to do such an experiment, especially here amongst all this positive mass, and especially to isolate the effects of gravity from electric and nuclear forces.

This is a common area that seems conceptually vague amongst every physicist I've personally spoken with and most of the ones I've read. Einstein seemed to clarify it best in his personal layman's version of relativity. People speak of the "size" of particles, and of "matter", as nebulous concepts separate from the force-fields which define the characteristics of those particles. For example, when pressed to define "volume" as an independent quality of a particle, as when people say "atoms are mostly empty space", most people, even physics professors, I speak to fail to give any definition.

Is it the size of an atom the radius of its outermost valence level? By that definition the entireity of space inside that valence shell IS the atom and is therefore not empty. So, scratch that idea, the space of the atom is only filled by the particles it's made out of and the rest is empty. Ok - what's the volume of an electron, or a proton? It's not clear how that should be defined - by it's mass? By its charge? How do you measure volume in units of mass or charge? Do you measure the volume by the extent that the strong nuclear force keeps other particles (of regular, non-antimatter at least) from overlapping that pointin space?

What is the extend or nature of something devoid of any of its force-fields? Can you run into an empty shell with no mass, charge, or nuclear forces? What exactly would you be running into? People say atoms are mostly empty space - I say everything is nothing but space, and none of it is empty.

From recollection, Einstein spoke in his laymen's book on relativity about an a c