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Positive Energy Warp Drive from Hidden Geometric Structures
- SmellTheGlove 5y agoThis sounds pretty amazing, but I also have no real idea what I'm reading. > A modest numerical analysis is carried out on a set of example configurations, finding total energy requirements four orders of magnitude smaller than the solar mass. Can someone smarter than me say whether this is within the (reasonable-ish?) realm of matter-antimatter reactions? Like Star Trek!? 4 orders of magnitude less than the sun's mass does sound like a positive development - still a lot but less than before, right?
- perl4ever 5y agoI think that's like 1/10th of Jupiter. Wasn't there a space drive that needed negative mass of about one Jupiter?
- akiselev 5y agoThe first paper detailing the Alcubierre drive required exotic particles with negative mass to achieve a spacetime bubble (soliton) which is an issue since particles with negative mass have never been observed. The next big paper figured out how to do it with regular matter and it brought the requirements down to the energy equivalent of four solar masses. That would put it squarely into the realm of a type II or III civilization (1 solar mass worth of energy is in the same ballpark as the amount a star puts out over its entire lifetime). If this paper is correct, it brings the requirements down to a tenth of Jupiter's mass, which is probably somewhat achievable for a type I civilization. The Enterprise would be the size of a small gas giant to hold an equivalent amount of matter and antimatter. It'd be able to enter warp once.
- TrevorJ 5y agoWould be interesting if paired with the harvesting of energy from a black hole. It is theorized that you can do this 'remotely' by slingshotting a laser around a black hole. This functions the same way a normal gravity assist does, except in this case it's photons, and not spacecraft. Shoot a laser around one side of a black hole, it returns to you around the other side, but at a higher energy wavelength. In this way, perhaps you would not need to store the energy needed 'in' your spacecraft, but instead in a black hole that is some safe distance away.
- AnimalMuppet 5y agoIf your laser beam doesn't spread so far that you can't harvest enough energy to be net positive, then the black hole is not going to be a safe distance away.
- TrevorJ 5y agoI supposed the term 'safe' is pretty relative in this case.
- samplatt 5y ago>It'd be able to enter warp once. ...why once? Are you assuming all matter+antimatter is destroyed in the single trip? If you have x amount of critical material, could you not warp for half the distance of the "fuel" in your "tank" and then come back? IANAPhyicist. I'm assuming that if we have the ability to contain and harvest energy from a matter/antimatter reaction then we also have the ability to stop it & start it at will.
- emeraldd 5y agoIANAPhyicist but if I understand what’s being said correctly the amount of energy necessary to create the warp bubble in the first place, would require converting something roughly the mass of Jupiter. So you’d twice that to “come back”. It sounds much more like surfing a wave that something that get’s turned on or off.
- akiselev 5y agoThe way I said it is misleading for the sake of brevity. That's a small gas giant worth of matter and antimatter to power a warp drive for a ship so small that it's not even worth calculating its mass relative to the fuel. The entire mass of Mount Everest is something like 0.00000000001% of the mass you'd need to create the warp bubble. If the ship was in the center of the fuel, it'd be crushed into something so dense it'd resemble the earth's core. Best case scenario we're talking a mass effect style planetary megastructure that forms a warp bubble around a ship and shoots it with just enough "momentum" for the warp bubble to fail right at the destination.
- ClumsyPilot 5y agoThe scale is all wrong. A type 1 civilisation is, rougly, civilisation that covered earth with solar panels. This drive needs a planet's mass in the form of pure energy, that's a totally different league. Also you dint have a planet to live on after that. This is a major stretch for even a type 2
- beervirus 5y ago> 4 orders of magnitude less than the sun's mass does sound like a positive development - still a lot but less than before, right? That’s something like 10^43 joules. Still not achievable anytime soon.
- XorNot 5y agoProgress in warp field research though has resulted in significant energy reductions though - everytime a more efficient formulation is found its a step on the way to a possible practical system. After all, if it was easy then everyone would be doing it.
- TrevorJ 5y agoWe've definitely achieved progress on this sort of scale with transistor density. Not that it's at all similar, but it's interesting to observe that we do seem to be able to occasionally bring things within our grasp that would have sounded absolutely silly a lifetime ago.
- WJW 5y agoDid we though? From milli- to nanometers is "only" 9 orders of magnitude. 10^43 J is about 30 order of magnitude from practical application than the first transistor was. Also, warp bubble generation might be more like electric motors, which have gone from ~2% to ~95% efficiency and will never ever surpass 100%.
- mcswell 5y ago"if it was easy then everyone would be doing it": And, I suppose, we'd see them. Little green men, I mean.
- mathw 5y agoWell that supposes that they currently exist, that they're close enough and that they want to come here. Maybe it is feasible to build an FTL engine, but maybe it can only feasibly go at like 4c. That doesn't make it very easy to drop by our solar system and have a look at what all that radio noise means, even if anybody's heard it.
- tobmlt 5y agoThe paper also gives recommendation for a starting point for some finite element modeling and optimization for field configurations requiring less energy than that, improving other properties and such. (FEM modeling to search the irrotational sector of the Hamiltonian constraint...) They mentioned this with a fair amount of enthusiasm - sounding like there may be room to optimize. I wonder what the gradients look like.
- ginko 5y agoThe Sun has a mass of about 2x10^30 kg. 4 orders of magnitude smaller would be 2x10^26 kg which is somewhere between the mass of Saturn and Neptune. So turn one of those into energy and you're good to go.
- senectus1 5y agoI honestly thought this article was going to lead to something written by Charlse Stross. I mean with lines like "A geometrical interpretation of the Eulerian energy is found, shedding new light on superluminal solitons generated by realistic energy distributions" I'm still not sure it wasn't...
- sigmoid10 5y agoIt might sound like gibberish to non-physicists, but it actually isn't. Eulerian energy is just the energy of something as observed by an eulerian observer, i.e. a normal observer traveling through spacetime (below the speed of light ofc). Solitons are just wave packets that keep their shape as they travel. None of the ideas presented here is new, not even the fact that these warp drives might work without negative energy. It's just a study of some more contrived geometries.
- krapp 5y agoYeah... using Euler geometries to generate warp fields always seems like the obvious solution at first, until you wind up stranded in hyperspace with gimbal lock. That's why you need to use quaternions.
- mcswell 5y agoDon't worry, your R2 unit can fix it.
- xelxebar 5y ago"Warp drives in Einstein's general theory of relativity provide a unique mechanism for manned interstellar travel. It is well-known that the classical superluminal soliton[0] spacetimes require negative energy densities[1], likely sourced by quantum processes of the uncertainty principle. It has even been claimed by few that negative energy densities are a requirement of superluminal motion. However, recent studies suggest this may not be the case. A general decomposition of the defining variables and the corresponding decomposition of the Eulerian energy are studied. A geometrical interpretation of the Eulerian energy is found, shedding new light[2] on superluminal solitons generated by realistic energy distributions. With this new interpretation, it becomes a relatively simple matter to generate solitonic configurations, within a certain subclass, that respect the positive energy constraint. Using this newfound interpretation, a superluminal solitonic spacetime is presented that possesses positive semi-definite energy[3]. A modest numerical analysis is carried out on a set of example configurations, finding total energy requirements four orders of magnitude smaller than the solar mass[4]. Extraordinarily, the example configurations are generated by purely positive energy densities, a tremendous improvement on the classical configurations. The geometrical interpretation of the Eulerian energy thus opens new doors to generating realistic warp fields for laboratory study and potential future manned interstellar travel." 0: Soliton - A "single bump" wave that propagates. See youtube for examples in water. These are (well-studied) solutions to the wave equation. In spacetime, we want some local "warp bubble" bump that is capable of moving/propagating around. 1: Negative energy density: Colloquially, this is like requiring negative mass. Nobody knows if this exists; most aren't hopeful. 2: Nice pun. 3: Positive semi-definite energy: I.e. non-negative (>=0) 4: So we're still talking mass-energies of Jupiter-(ish)-sized planets This is very cool stuff. Definitely going to read the whole paper after work. Current questions: - Is this really superluminal? Famously, the Alcubierre "warp bubble" solution doesn't actually propagate you superluminally unless you start it off that way. - Is there a Minkowskian interior? The warped part of space is like your engine. We also need to have it carry around some flat space if we want it to be capable of carrying passengers. - Can we construe this into PoC tests? How much energy do we need to detect warping (e.g. laser deflection) with current tech? Could some large-scale LIGO-like setup achieve detection?
- gfodor 5y ago
- gary_0 5y agoWhat do the authors of these warp drive papers think will happen causality-wise when the proposed vehicle effectively moves faster than c? You can't do that without doing nasty things to your light cone[0] and effectively traveling into your own past. Is a prerequisite of entertaining the idea of a warp drive that we disregard causality? As far as I know, there aren't any plausible loopholes in General Relativity that allow you to pop up anywhere and anywhen you want in spacetime. [0] https://en.wikipedia.org/wiki/Light_cone https://en.wikipedia.org/wiki/Light_cone
- XorNot 5y agoWell for one thing, a speed-of-light limited warp drive would still be effectively a reaction-less drive we could use for travel in the solar system. But a decent way to beat Einstein would be find and implement an actual FTL engine: after all, if you can do it then obviously the theory isn't correct (alternately: the universe possible does not care about causality as much as we do in our little bubble of perception).
- gary_0 5y ago> would still be effectively a reaction-less drive True, but if the energy requirements for warp drives continue to be measured in Jupiters, reaction-mass is the least of your worries.
- iamnotwhoiam 5y agoI think with that much energy the light pressure alone would get you wherever you wanted to go.
- tsimionescu 5y agoThe whole point of warp drive FTL, and the reason it's the only kind of FTL idea taken seriously, is that it wouldn't violate GR. We already have widely accepted physical theories that contain exactly this kind of FTL 'travel': the Big Bang theory posits that space in the early universe expanded faster than the speed of light.
- 5y ago
- gfodor 5y agoThere is the threshold where these theories rule in human plausible warp drives, and then there is the weaker threshold where these theories rule in that they should be taken as serious explanations for the alleged “advanced technology” demonstrated by UAPs. I wonder what we ought to expect to see from such a device as an observer if the geometric formulation here is correct, even if we can’t explain the energy management problems. It sure would be nice if this research adds tools to the scientific community to start forming decent falsifiable hypotheses within the scope of an assumption of a given incident being such a tech demo.
- visualradio 5y ago> then there is the weaker threshold where these theories rule in that they should be taken as serious explanations for the alleged “advanced technology” demonstrated by UAPs No, it doesn't really do anything to weaken the threshold. If humans discover a method of warp travel which is then validated by peer review, this does not do anything to increase the reliability of claims made by the US Air Force concerning the existence and performance characteristics of UAPs. The reliability of the later claims are limited by the fact that there is no independent observation and verification from non-military sources, and due to the fact that former USAF employees such as Richard Doty have claimed they were hired to fabricate and provide false information to independent UFO researchers as part of a domestic counter-intelligence operation.
- gfodor 5y agoYou're not understanding what I am saying. Also the US Air Force is explicitly not involved in the latest disclosure regarding UAPs, so I suspect you're not fully up to date on everything. My point is that if a theoretical model for a warp drive emerges that provides falsifiable hypotheses in terms of what an external observer ought to see, this could be a useful tool for scientists to use if/when they are given the underlying UAP data I expect to see the government hand over the next 12-18 months. The threshold I am referring to is when the theory becomes cohesive enough to provide such a tool for being able to generate such explanations, as opposed to the threshold where it could lead to actual applied physics.
- DubiousPusher 5y agoI'll give you a "hidden geometric structure".
- canjobear 5y agoPrevious work seemed to conclude pretty strongly that superluminal warp travel required negative energy. What's the insight here that gets around that?
- jxf 5y agoThe goal of warp drive is to produce a modified region of spacetime that makes it feasible to travel faster than light. There are an infinitude of different approaches. The authors in this paper find that if you impose specific constraints on the way the modified region of spacetime is shaped and evolves over time, you don't need the negative energy anymore. However, you do need a very high energy density, strong enough to create a black hole. And there is, of course, no guarantee that such an energy source is feasible or even possible. But you no longer need exotic matter — you just need enough regular matter in one spot.
- native_samples 5y agoThe sociology of this is fascinating. For my whole life I've heard that travelling faster than light is not only impossible, but so obviously absurdly impossible that only loons and sci-fi writers bother to think about it at all. Now I'm reading that "There are an infinitude of different approaches" to the problem! What exactly is the breakthrough that has led to this recent spurt of warp drive papers? As far as I can tell the results are all purely theoretical and just re-arranging equations. None of them appear to rely on any recently lab discovered physics. Why couldn't this have been done in 1950, I wonder?
- Majromax 5y ago> What exactly is the breakthrough that has led to this recent spurt of warp drive papers? As far as I can tell the results are all purely theoretical and just re-arranging equations. None of them appear to rely on any recently lab discovered physics. Why couldn't this have been done in 1950, I wonder? By "recent", you have to go back almost 30 years to the Aclubierre Drive (https://en.wikipedia.org/wiki/Alcubierre_drive https://en.wikipedia.org/wiki/Alcubierre_drive) described in 1994. It forms part of the "we can come up with some interesting solutions to general relativity" literature. That literature is not just a recent phenomenon. Research into theoretical wormholes (https://en.wikipedia.org/wiki/Wormhole#Development https://en.wikipedia.org/wiki/Wormhole#Development) goes back decades further.
- cletus 5y agoThe lesson we should really take here is the power of wishful thinking. People dearly want to believe in FTL travel. Without it, the Universe just seems so vast, empty and distant. The truth is it is and it isn't. It's only really that on our current time scales. Not to be a broken record (there's some new variation on some old idea like every week it seems), but I'm firmly in the camp that believes FTL isn't possible. There are two prongs to that. 1. Theoretical: a lot of these theories rely on people not understanding the domain of a function (eg plugging in negative mass or energy into an equation; just because a function can operate over real numbers doesn't mean real numbers are the domain of that function); and 2. The macro evidence in that if FTL were possible it makes it that much more unlikely that we haven't detected starfaring life. Specifically, the potential volume of spacetime goes from a line cone of several million light years to the entire Universe (not just the observable Universe). We don't know how big that is of course but it's may orders of magnitude larger. So this paper tries to "solve" the negative energy/mass problem. I honestly can't speak to the soundness of this idea. I am however skeptical.
- jack_pp 5y agoIsn't there evidence starting to surface that we have actually detected alien contact?
- IdiocyInAction 5y agoYou mean that UAP stuff? Occam's razor says this is probably some electronic countermeasure stuff by the US or something.
- randmeerkat 5y agoMaybe, or what if it’s exactly what the DoD is saying? That there’s verified advanced UAPs beyond our current technological understanding.
- stjohnswarts 5y agoI don't they said "there are uaps beyond..." , they said they couldn't explain all of them, that's all.
- godelski 5y agoEveryone always talks about FTL travel for spacecraft, but there's also an interesting perspective from weapons side (and this a reason to be a bit careful and think about some ethics as we move along). A FTL kinetic weapon would be devastating. If it comes with a collapsing warp bubble then there's basically a gamma ray "gun" that travels right in front of your mass that is traveling at tremendous speeds. You look at impacts on the ISS and you can see how much damage a small object does[0]. This is also especially important when trying to develop such a device for travel as you'll probably be sending small objects before a spaceship, or rather a "bullet". Where that object ends up may be in serious danger. Edit: And as others are pointing out, communication. There's a whole slew of technologies that could be improved/invented if you can move things/information FTL. [0] https://www.esa.int/Safety_Security/Space_Debris/Hypervelocity_impacts_and_protecting_spacecraft https://www.esa.int/Safety_Security/Space_Debris/Hyperveloci...
- hyperpallium2 5y agoIf we're talking surprising applications of FTL, what about reducing latencies within CPUs?
- R0b0t1 5y agoThis is a good one. The limits on the mass needed to construct the system are quite large, but perhaps you can get a weaker effect much more easily.
- godelski 5y agoThis would also be neat. And of course any information communication. While Ansibles[0] are typically used to verbally communicate with someone why not any information? [0] https://en.wikipedia.org/wiki/Ansible https://en.wikipedia.org/wiki/Ansible
- evilduck 5y agoThat was sort of a primary plot point of the Ender's Game series.
- api 5y agoIf FTL is possible (and engineerable) then the Fermi paradox becomes a serious problem. There "should" be aliens all over the place unless... (1) We are wrong about the nature of the universe and strong theism / creationism or the simulation hypothesis (which is the same thing more or less) are right. (2) Life or complex life are so phenomenally unlikely that we are literally the only example in the local galactic supercluster at least, if not the whole universe. Speaking of creationists they often argue that the probability of life forming from non-life is insanely low. Maybe they're right about those probabilities and it only happened once. (3) We live in a cosmic cemetery. There is a big nasty great filter ahead of us, and nobody has passed so far. Maybe the great filter is when you try to actually build FTL and cause a space-time catastrophe. (4) We live in a "dark forest" and should be very, very quiet. Shhhhh.... (5) We live in a nature preserve. See #6. (6) Last but not least, at least some UFOs really are ETs in which case there is no Fermi paradox. They're here and we have seen them. They're just laying low and not making overt contact. My money would be on 6. If we demonstrated some kind of engineerable FTL I'd take the possibility that at least a few UFOs are ETs very seriously.
- postalrat 5y agoFermi's paradox does not depend on FTL travel.
- api 5y agoNo, but the difficulties of conventional interstellar travel provide some cushion in any model. If you can build a USS Enterprise that cushion goes away.
- anonydsfsfs 5y agoOr 7) FTL is possible, but the amount of energy required is so insanely large it doesn't matter. The paper says it takes energy equivalent to "four orders of magnitude smaller than the solar mass", which is an absurd amount. This reminds of an interview I read with Donald Knuth about the P vs. NP problem. IIRC, Knuth said he believes there probably is a polynomial time algorithm to solve NP problems, but the constant factor will be so absurdly huge (e.g. Graham's number) that it could never be run on an actual computer. I've heard layman claim that if P=NP were proven, then it'd suddenly spell the end of encryption relying on NP problems, but it's entirely possible that it'd have no practical impact. The constant factor is analogous to energy requirements for FTL.
- wait_a_minute 5y agoam i expected to know this in interviews now
- doctoboggan 5y agoPBS Spacetime has a video discussing the recent theoretical advances in warp drives. It does not cover this paper but does discus a paper that also claims to solve the negative energy problem. https://www.youtube.com/watch?v=Vk5bxHetL4s https://www.youtube.com/watch?v=Vk5bxHetL4s
- nabla9 5y agoIt's my understanding that warp drives can't travel faster than light (superluminal) into new destinations. You must first create the soliton in subliminal speed, then you can move faster than light. In other words, if you wan to travel 100 light years, you must first spend more than 100 years warping the spacetime towards the destination, then you can move FTL.
- YoungWeb 5y agoIt never ceases to amaze me how smart some people are.