21 ms·
Travel through wormholes is possible, but slow
- SketchySeaBeast 8y agoCan someone point out where the article says why it's slower? I'm having difficulty unpacking: "The new theory was inspired when Jafferis began thinking about two black holes that were entangled on a quantum level, as formulated in the ER=EPR correspondence by Juan Maldacena from the Institute for Advanced Study and Lenny Susskind from Stanford. Although this means the direct connection between the black holes is shorter than the wormhole connection—and therefore the wormhole travel is not a shortcut—the theory gives new insights into quantum mechanics." Why is the wormhole not a shortcut?
- philipov 8y agoBased on the colloquia I watched by Lenny Susskind, the problem is that you can put something into a wormhole, but to get it out the other end, you have to carry the encoding you get to the other end of the wormhole to decode the output. Because the distance to the singularity grows at the speed of light, the length of the wormhole is essentially infinite. It is only the operator you get from putting the object into the wormhole that lets it tunnel through that infinity, so no shortcut. EDIT: Here is the lecture I'm referring to: https://www.youtube.com/watch?v=nEDFh8ma9zM https://www.youtube.com/watch?v=nEDFh8ma9zM
- SketchySeaBeast 8y agoSo we've uncovered the universes version of cyptography?
- TomMarius 8y agoNative cryptography, I'd say
- jessermeyer 8y agoIt's more just the encryption method without decryption.
- lawlessone 8y ago> Because the distance to the singularity grows at the speed of light, doesn't our universe expand at the same speed?
- adrianN 8y agoThings are moving away from us at a speed proportional to their distance. The fastest objects are actually faster than the speed of light.
- FrancoisBosun 8y agoI thought nothing could move faster than light?
- philipov 8y agoSpecial Relativity states that no two objects may pass each other faster than the speed of light. Space itself isn't bound by this restriction. To wit: no thing can move faster than the speed of light, but space is not a thing. Space is dynamical. It can stretch and expand and even break, but it doesn't move. The result of this is a cosmological horizon that prevents these objects from communicating, because the distance between them is growing faster than light can cross it. This is the same reason you can't escape a black hole.
- pbhjpbhj 8y ago>and even break Spatial discontinuities? Can you tell us more, please?
- philipov 8y agoHow about another lecture by Leonard Susskind? I'm just repeating his ideas! The gist of it is that the connectivity of space is related to the patterns of entanglement between particles in the quantum foam. If you were to break that entanglement, you could disconnect two regions of space. https://www.youtube.com/watch?v=9crggox5rbc https://www.youtube.com/watch?v=9crggox5rbc
- logfromblammo 8y agoSo... Two entangled wormhole apertures function as Star Trek style transporter pads. Feed mass into one hole, scanning it as it goes in. Transmit the pattern to another aperture of the hole, using electromagnetic energy at the speed of light, and when that end ejects a mass, apply the pattern to it, so it resolves into an exact copy of what you put in. The distance the mass travels may be shorter than the distance the energy travels, but it can't resolve exiting mass as that object until the information--that had to travel at the speed of light--arrives. So you could potentially use a wormhole as a suicide machine that transports a copy of you, that thinks it actually is you, to a distant location no faster than the speed of light, in zero subjective time for the thing that will then think it's you. Is that a reasonable interpretation?
- ben_w 8y agoI don’t think the suicide booth model of a teleporter fits a quantum teleporter model, only the 3D printer teleporter model. From a quantum point of view, all (e.g.) electrons are indistinguishable excitations in the same field, and it’s the pattern that makes you “you”. If you’ll forgive a bit of poetic licence, quantum teleportation seems more like Discworld magic, where you have to exchange two identical sized lumps of matter.
- lloeki 8y agoThis sounds like the science-fiction version of a cryogenic scam.
- pontifier 8y agohttp://existentialcomics.com/comic/1 http://existentialcomics.com/comic/1 Edit:Lol, someone else also had this link as a reply to a similar thought.
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- Terr_ 8y ago> the problem is that you can put something into a wormhole, but to get it out the other end, you have to carry the encoding you get to the other end of the wormhole to decode the output. That sounds a lot like how entangled particles can't be used to communicate faster than light. While you can make observations immediately, you can't turn them into useful information about the other end, at least not until you get missing data which has to reach you by normal means. Hence the focus on using entangled particles as a kind of tamper-detector or "reusable random one-time pad", rather than for transmitting information.
- philipov 8y agoThat is precisely the lesson of the ER=EPR principle, which states that every entangled pair really has a 1-qubit wormhole connecting it, and the space inside a macro-scale wormhole is the consequence of combining all those tiny wormholes together. Wormholes are entanglement.
- eigenschwarz 8y agoThe Average Null Energy Condition (ANEC) makes it so there can not be a traversable wormhole joining two otherwise disconnected regions of spacetime. So by construction, any infinite null geodesic (a light ray) which makes it through the wormhole must be chronal (causally connected). This means there can be no traveling faster than light over long distances by going through one.
- FakeComments 8y agoYou don’t really explain how the assumption leads to the conclusion — and I’m left with the impression you used many words to say “they just assumed you can’t”. Could you elaborate? Edit: Looking into energy conditions further, they are literally assumed restrictions on the equations because physicists felt some predictions were unphysical. I’d really like if someone could explain if there’s any justification to what I was responding to beyond “well, because we assumed it should work that way”. I think it behooves the physics community to be honest which claims are conclusions and which are their assumptions, and the specific reasoning that leads from assumption to conclusion.
- Filligree 8y agoWithout negative matter, it's impossible to build a wormhole that's shorter than the distance through normal space. This piece of math shows that it may still be possible to build a wormhole which isn't shorter than that distance. Obviously that wouldn't be much of a shortcut, but the potential research and (maybe) real-world applications are still impressive.
- FakeComments 8y agoThat’s not what I was asking. I was asking about the particular usage of the average null energy condition as justification to rule out wormholes: why isn’t that just begging the question by assuming your conclusion? and how does that particular assumption actually lead to the conclusion there can’t be wormholes? It’s interesting the downvotes for asking someone to support a scientific claim, and be clear where they’re making assumptions versus reaching empirical conclusions.
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- jaequery 8y agoWhen ever I think of traveling through a wormhole/blackhole, I imagine you would be squished and crushed and come out the other end as pure vaporized energy. This makes me wonder, if there is the potential for our beings (or things) be able to be vaporized and then recreated to original form. If we are just mass and particles, this should be possible?
- JoeAltmaier 8y agoIts all about information. The order of atoms to make a person is information. No information passes thru the event horizon of a black hole. So, no.
- nikofeyn 8y ago> No information passes thru the event horizon of a black hole. that is only true in one direction though, right?
- Retra 8y agoThere is only one direction through the event horizon of a black hole.
- Consultant32452 8y agoI thought Hawking radiation was going the other direction, but that it doesn't carry information about the original mass/energy. Is that right?
- Retra 8y agoI don't think there's a definitive answer there, nor any reason to believe Hawking radiation is produced inside an event horizon, rather than just outside it. The event horizon is pretty much defined by the boundary that radiation will not escape across, so I wouldn't assume Hawking radiation behaves any differently with respect to it.
- dosy 8y agoDoes anyone here ever question if there's a secret space program? Trillions of dollars of pentagon money just vanished. Whistle-blowers come forward. Patent suppression, TR-3B/Black manta sightings worldwide. But mainstream "science" and "tech", know nothing about it, right? Little bit strange. What's stranger is how wages and standard of living (minus a few tech devices) hasn't changed much in 30 years. Air travel in 50. Anyone else think about this? What if humans from earth are already out among the stars, and a few powerful interests just don't want to tell the rest of us, and justify it under "the public would panic" or "oil economy would crash"?
- weregiraffe 8y agoParagraphs. Use them.
- dosy 8y agoup votes. use them
- jbob2000 8y agoWe would know. Either the secret space program requires enough exotic materials and science that you wouldn't be able to hide it OR it doesn't require that, so it's simple enough that any one of us could stumble upon it. Trillions of dollars vanished because humans are probably more greedy than they are curious.
- docode 8y agoIt's possible.
- vectorEQ 8y ago"To date, a major stumbling block in formulating traversable wormholes has been the need for negative energy, which seemed to be inconsistent with quantum gravity. " it appears thus, most humans are inconsistent with quantum gravity :D:D
- noobermin 8y agoI'm not sure if this is the researchers' issue or is an issue with the scientific press, but it would help if the "discoveries" theorists made with their hitherto unestablished and untested theories like various string and QG based theories were not touted as discoveries about the real world.
- PaulHoule 8y agoQG is funny. There are some results around QG, such as holography, which seem to be universal. That is, they make sense with strings, loop quantum gravity or any of about ten other lines of work that people can do quantum gravity calculations with today. If you can prove that all of those have to say the same thing, that is a powerful result and probably means something about our world. It seems pretty reasonable that wormholes could exist so long as they don't form closed-timelike curves, so I think these people are getting at the quantum roots of the "cosmic censorship principle".
- rstuart4133 8y ago> It seems pretty reasonable that wormholes could exist so long as they don't form closed-timelike curves "Wormholes" are two entangled black holes that have been subsequently moved light years apart, preserving the entanglement during the move. They are a great mathematical toy for exploring the nature of entanglement. But that's it. We have trouble preserving the entanglement of just a few ultra cold particles for a few milliseconds. I am far^^^far more likely to fall onto the floor by quantum tunnelling through my chair than a useful wormhole ever appearing. Postulating they actually exist is not in the slightest bit reasonable.
- krastanov 8y ago"Discoveries" about the mathematical structure of these theories are actually incredibly important even if no current day experiment can conceivably test them. Special and general relativity were discoveries made in this way (at least to an extent), and now general relativity is important for the proper functioning of technology as "trivial and boring" as GPS. Even earlier in our history, much of thermodynamics was developed in a similar fashion. See the sibling comment for another version of this argument, but finding the weird mathematical coincidences between the competing mathematical theories of nature is very useful. In other words, there are mathematical and logical tests that can be as important as experimental tests for the progress of our understanding of nature.
- readtheplaque 8y agoGeorge R. R. Martin called it in 1974! :) https://scifi.stackexchange.com/questions/84453/scientist-discovers-hyperspace-with-a-twist/84454#84454 https://scifi.stackexchange.com/questions/84453/scientist-di...
- Abishek_Muthian 8y ago>To date, a major stumbling block in formulating traversable wormholes has been the need for negative energy, which seemed to be inconsistent with quantum gravity. However, Jafferis has overcome this using quantum field theory tools, calculating quantum effects similar to the Casimir effect. Prof. Stephen Hawking has explained the Casimir effect in hist last book 'Brief Answers to the Big Questions' in the chapter talking about Time Travel with Wormholes. "Imaging that you have two parallel metal plates a short distance apart. The plates act like mirrors for the virtual particles and anti-particles. This means that the region between the plates is a bit like an organ pipe and will only admit light waves of certain resonant frequencies. The result is that there are a slightly different number of vacuum fluctuations or virtual particles between the plates than there are outside them, where vacuum fluctuations can have any wavelength. The difference in number of virtual particles between the plates compared with outside the plates means that they don't exert much pressure on one side of the plates when compared with the other. There is thus a slight force pushing the pates together. This force has been measured experimentally. So, virtual particles actually exist and produce real effects. Because there are fewer virtual particles or vacuum fluctuations between plates, they have a lower energy density than in the region outside. But the energy density of empty space far away from the plates must be zero. Otherwise it would warp space-time and the universe wouldn't be nearly flat. So the energy density in the region between the plates must be negative"
- philwelch 8y agoIt seems to me that the speed of light, like conservation of energy, is just one of those fundamental “no free lunch” rules of physics that we just plain can’t cheat.
- krastanov 8y agoI would urge people interested in this topic to read the hard scifi work of Greg Egan. In particularly, Diaspora. It is fascinating how much overlap is between this mathematical work and his work of "mathematical fiction".
- drdeca 8y agoWhy doesn’t this violate the topological censorship result?
- house_atr 8y agoBut could we do things inside the wormhole that we couldn't do in regular space? To go faster anyway?