5 ms·

Scientists Are Starting to Take Warp Drives Seriously

49 points by elorant 7y ago

pingyong 7y ago
tldr: Nothing changed, we still don't know if negative energy is even something we can generate.
- Pigo 7y ago
  But they got it down to only needing the total negative energy requirement to be around the mass of Jupiter. So we're on our way?
  - jerf 7y ago
    That's one way of looking at it. No sarcasm, I'm serious. But another valid way of looking at it is that scientists have moved it from "impossible", to "impossible", to "impossible", then, with some more work, upgraded it to "impossible". Or, in other words, no progress at all. The negative mass is still only one problem with the Alcubierre drive concept. Last I knew, it remains unclear how to enter and/or create a bubble without being totally destroyed, or exit and/or destroy a bubble without being totally destroyed. Reuse of any of the components is probably also a problem; in the Einstein equations, playing fancy games with spacetime tends to want to rather explosively go back to normal with the entire mass-energy of the distortions in question. It's also somewhat unclear what would happen to an Alcubierre warp drive in the real universe, where the space between stars is not a perfect vacuum. It's not a drive being taken "increasingly seriously", unless you mean it's gone from epsilon to twice epsilon. It's a particular solution of the Einstein equations that involves impossible quantities of things and a particularly complicated setup basically already existing. If we didn't have science fiction making FTL drives cognitively available to people's imaginations and perhaps even subconsiously bleeding over into people's impressions of what real is (i.e., the bizarre but clearly pervasive subconscious assumption that seeing something in a sci-fi show means the probability of that occuring in real life is higher), nobody would be taking this seriously right now. Between the actively impossible elements (sustained, enormous quantities of negative mass) and the things that may not be mathematically "impossible" but are probably engineering-impossible, this is just a thought experiment right now. Now, for all that, it's a worthy thought experiment. I am a firm believer in putting down a bit of money on the very long-shot payoff research. I'm not asking anyone to stop working on it. I'm just asking for realistic assessments of the current state of the art, which is that the probability that this drive will ever work is basically indistinguishable from zero at this point.
    - ColanR 7y ago
      > But another valid way of looking at it is that scientists have moved it from "impossible", to "impossible", to "impossible", then, with some more work, upgraded it to "impossible". I think that description used to apply to a lot of technology, which then progressed to "almost impossible", "slightly less impossible", and finally to "built a prototype". From my laymans' perspective, it's the trajectory that matters more than the current state-of-the-art.
      - jerf 7y ago
        Not the way I'm using the word. The drive is not currently merely like an airplane, where it is obviously possible to fly (at least as well as birds), we just didn't know how to bang the rocks together correctly to do it. The Alcubierre drives requires things that we have every reason to believe are impossible. In English the term "negative mass" may just seem like, oh, someday maybe we'll advance and have this; in math, it's even worse than you may think I'm going to say. It isn't that we don't know what "negative mass" is. It in fact already appears in some of our equations. The problem is that the product of negative mass times the amount of time it exists seems to be fairly sharply bounded at literally dozens of orders of magnitude too small to conceivably be of any use. We have every reason to believe that stable negative mass is impossible. Not just "we don't know how to do it yet", but impossible. Impossible is like "perfect"; technically, it doesn't admit of "degrees" of impossible. So moving from "impossible" to "impossible" is not progress. People like to cite a lot of cases of various supposed boundaries being broken over time as evidence that maybe this one will be broken too, but there's a qualitative difference between some "elderly distinguished scientist" opining something is impossible, and the mathematics of physics saying something is impossible. It is not a sophisticated, open-minded position about the technological possibilities of the future to say that someday, man will break the barriers of the laws of thermodynamics and someday produce the perpetual motion machine; it is ignorance and scientific illiteracy. FTL is not quite that certain yet, but at the moment, the smart money is on it being the exact same sort of thing, not humanity someday overcoming it. At the moment I'd say that if you properly understand the science of the matter and just how thoroughly reality seems to stymie us in our every attempt to worm around the speed of light restriction, you are completely unjustified in giving even a .1% chance of FTL being possible, let alone that humanity will ever achieve it. It looks to be a lot closer to perpetual motion than breaking the sound "barrier", which barely even deserves the same English word as the speed of light barrier given their massive qualitative differences. Now, as I say, the long shots sometimes pay off, so I don't advocate that nobody thinks about this. Even the process of discovering why the <.1% is better thought of as a flat 0% can be valuable scientific progress, plus there is always the chance I'm wrong. However, at the moment, it looks like FTL is a problem that is far harder than just waving a couple of hoary old quotes about scientists at it is going to solve. You're not fighting "scientists", but the math. Personally, I tend to think Hawking probably got it right with his chronology protection conjecture, and that even if you do manage to build something that goes faster than light or travels back in time, the entire system will literally explode. FTL may not be just impossible because we don't know how to build it, but because it really is fundamentally impossible; spacetime will literally explode in your face even if you do manage it. https://en.wikipedia.org/wiki/Chronology_protection_conjecture https://en.wikipedia.org/wiki/Chronology_protection_conjectu...
  - pingyong 7y ago
    Honestly the amount doesn't even matter. If we could make a baseball amount of negative energy but needed a Jupiter amount, sure, that looks solvable. But we don't even know if it's theoretically possible to create a baseball amount of negative energy. As long as that question hasn't been answered, any discussion about practical applications seems rather pointless.
- baja_blast 7y ago
  There has been some experimental progress for negative mass from Bose-Einstein condensate https://en.wikipedia.org/wiki/Negative_mass https://en.wikipedia.org/wiki/Negative_mass to some interesting potential properties of future meta materials.
contravariant 7y ago
I think it's always been taken somewhat seriously from the start of general relativity (it didn't take long before the first formal description of a wormhole). The discovery of gravitational waves has again provided strong proof in favour of general relativity, but I don't think this is what is preventing people from seriously considering warp drives. Until a way is found to remove the need for exotic matter or to generate exotic matter it remains a purely theoretical exercise.
- qubex 7y ago
  The problem isn’t really the need for exotic matter in enormous quantities (apparently we have a negatively curved universe where dark energy serves exactly that purpose), but rather the aspect of causal disconnection: everything inside the bubble is disconnected from everything outside it, so it’s difficult to envision how the spacecraft inside could be generating, steering, or even shutting down the warp bubble outside itself.
honoredb 7y ago
Typo near the beginning, "press a petal," gave me a fascinating mental image for a second. I'm sure it'll be informative to learn exactly why every theoretical avenue for faster-than-light travel doesn't work, but I feel like we can infer from the size of the universe that these effects don't exist; if they did, they'd dominate our observations of the universe and we'd never have thought the speed of light was a fundamental limit in the first place.
- nateferrero 7y ago
  Flower petals would make an amazing tactile controller
Vysero 7y ago
Sounds to me like they are discussing tech that may exist 5 to 6 hundred years from now... not really worthy of their attention imo.
- pluto9 7y ago
  For it to exist 500 years from now, someone will have to work on it for the next 500 years.
  - Vysero 7y ago
    That's not true. What it would take is a massive advance in material science or what-have-you. Once that massive advance happens then it may or may not make this tech possible. However, that massive advance will most likely have nothing to do with working on this particular tech in the meantime.
mellosouls 7y ago
Scientists Are Starting to Take Warp Drives Seriously No they aren't. This is just a fluff piece for a highly speculative but excitingly sci-fi sounding propulsion mechanism with not even the remotest prospect of practical implementation. See also EM Drive, etc.
- deleted 7y ago
  [deleted]
- hhas01 7y ago
  Never mind implementation; what about causality? https://en.wikipedia.org/wiki/Causality_(physics) https://en.wikipedia.org/wiki/Causality_(physics) Anyone who wants to build a warp drive has to start by proving Einstein wrong. Anything else is a scam.
  - rootbear 7y ago
    Yes, this is my problem with such “warp drive” articles. They rarely address the causality issues with ALL forms of FTL travel.
  - alfromspace 7y ago
    How does FTL violate causality? I've tried reading on it before but didn't understand it with my casual understanding of physics.
    - shadowgovt 7y ago
      This website explains it much better than I can, but the tl;dr explanation is there's no "privileged frame of reference" in relativity. Even if two frames of reference can be arranged to agree on a causal sequence involving FTL phenomena, a third observer can be constructed that perceives the sequence of events happening out of order; they get the light from effect before they get the light from cause. This creates nasty phenomena that we don't seem to observe in nature (i.e. if the third party observes effect before cause, they can interfere with cause. Everyone loves a good temporal paradox ;) ). http://www.physicsmatt.com/blog/2016/8/25/why-ftl-implies-time-travel http://www.physicsmatt.com/blog/2016/8/25/why-ftl-implies-ti...
tjchear 7y ago
I've heard often about how the energy estimate for warp drive has been revised down from the mass of the universe to that of Jupiter. Forgive my ignorance, but is this just a matter of refining the shape of the warp around a spaceship, or is it something else? What would it take to further drive down that theoretical energy requirement? Is there a trade-off being considered here?
- qubex 7y ago
  It is the result of refining the geometry of the warp bubble to be generated by two toroids rather than a single ring, inflating the interior compared to the external perception thereof (a la Tardis), and most critically, by oscillating the field.
mnky9800n 7y ago
sciencealert is starting to post non-clickbait articles. wait no they aren't. lol.
ptah 7y ago
how is this different from aether https://en.wikipedia.org/wiki/Aether_theories https://en.wikipedia.org/wiki/Aether_theories
- juped 7y ago
  Using "aether" as a generalized snarl word is really irksome. None of us were alive for the debates in physics of a century ago. General relativity is an aether theory; i.e., it ascribes properties (the metric tensor) to empty space. Appeal to authority below since that's the level we're playing on when we misuse dated terminology like this. "We may say that according to the general theory of relativity space is endowed with physical qualities; in this sense, therefore, there exists an ether. According to the general theory of relativity space without ether is unthinkable; for in such space there not only would be no propagation of light, but also no possibility of existence for standards of space and time (measuring-rods and clocks), nor therefore any space-time intervals in the physical sense." -- Albert Einstein
  - ptah 7y ago
    sorry, i was just curious. i didn't know people felt that strongly about it
  - taylodl 7y ago
    Don't confuse the model with reality. The interesting thing about GR and its stress-energy tensor is you can't distinguish the model from the reality. The model says space is curved and it's this curvature which we perceive as gravity. Does that mean space is actually curved? No. But we have no way to tell. It's a fascinating concept when you think about it. Quantum gravity may give us a way out but so far we've achieved little progress, mainly due to the very same stress-energy tensor being a different type than those found in other quantum fields. Viktor Roth provides a simple explanation of the problem: https://www.forbes.com/sites/quora/2017/05/17/the-marriage-of-einsteins-theory-of-relativity-and-quantum-physics-depends-on-the-pull-of-gravity/#65399968e3a6 https://www.forbes.com/sites/quora/2017/05/17/the-marriage-o.... If you're into physics Viktor is a fun guy to follow on Quora.
- 7y ago
34679 7y ago
>Please don't post shallow dismissals, especially of other people's work. A good critical comment teaches us something. https://news.ycombinator.com/newsguidelines.html https://news.ycombinator.com/newsguidelines.html Just a reminder.
reportgunner 7y ago
If you like the idea of Alcubierre Drive, give Elite: Dangerous a try - every ship (that is not a fighter) has an Alcubierre Drive installed and you use it extensively to get around "The bubble" (a sphere of inhabited space roughly 20 light years with Earth as its centre) and even beyond. I have no affiliation with Elite: Dangerous, that's just how I learned about Alcubierre Drive
diegoperini 7y ago
"Scientists" is not single community of converging opinions. "Scientists" do not even agree on how serious the climate change is. Prefixing these kind of titles with "Some" (as in "Some Scientists...") may seem redundant but it actually gives an entirely different message which I believe is almost always important to be explicit about.
unknownkadath 7y ago
I feel really bad for this undergrad; The student's advisor did not do him any favors by letting him go and give this talk to the IEEE. It is perfect material for clickbait farms and the wider krank-net. If you can access it, the doi link to the conference paper is: doi.org/10.2514/6.2019-4288 This is not a serious attempt, and in no way indicates that scientists are starting to "take warp drives seriously." It is pitching that same silly stuff White et al have been promising is "real close now" for around 15 years. I also cringed at the equations and figures that were obviously copy/pasted from White's PDFs to Word and back. Having this kind of kooky thing hanging from a baby undergraduate's name--a name that I'm not going to propagate on the web for his own good--is not going to help his future career, and everyone involved should feel bad for wasting his time. Sorry this is boiling my grits so badly, am I over reacting or is this awful?

49 points by elorant 7y ago

pingyong 7y ago

tldr: Nothing changed, we still don't know if negative energy is even something we can generate.

Pigo 7y ago
But they got it down to only needing the total negative energy requirement to be around the mass of Jupiter. So we're on our way?
- jerf 7y ago
  That's one way of looking at it. No sarcasm, I'm serious. But another valid way of looking at it is that scientists have moved it from "impossible", to "impossible", to "impossible", then, with some more work, upgraded it to "impossible". Or, in other words, no progress at all. The negative mass is still only one problem with the Alcubierre drive concept. Last I knew, it remains unclear how to enter and/or create a bubble without being totally destroyed, or exit and/or destroy a bubble without being totally destroyed. Reuse of any of the components is probably also a problem; in the Einstein equations, playing fancy games with spacetime tends to want to rather explosively go back to normal with the entire mass-energy of the distortions in question. It's also somewhat unclear what would happen to an Alcubierre warp drive in the real universe, where the space between stars is not a perfect vacuum. It's not a drive being taken "increasingly seriously", unless you mean it's gone from epsilon to twice epsilon. It's a particular solution of the Einstein equations that involves impossible quantities of things and a particularly complicated setup basically already existing. If we didn't have science fiction making FTL drives cognitively available to people's imaginations and perhaps even subconsiously bleeding over into people's impressions of what real is (i.e., the bizarre but clearly pervasive subconscious assumption that seeing something in a sci-fi show means the probability of that occuring in real life is higher), nobody would be taking this seriously right now. Between the actively impossible elements (sustained, enormous quantities of negative mass) and the things that may not be mathematically "impossible" but are probably engineering-impossible, this is just a thought experiment right now. Now, for all that, it's a worthy thought experiment. I am a firm believer in putting down a bit of money on the very long-shot payoff research. I'm not asking anyone to stop working on it. I'm just asking for realistic assessments of the current state of the art, which is that the probability that this drive will ever work is basically indistinguishable from zero at this point.
  - ColanR 7y ago
    > But another valid way of looking at it is that scientists have moved it from "impossible", to "impossible", to "impossible", then, with some more work, upgraded it to "impossible". I think that description used to apply to a lot of technology, which then progressed to "almost impossible", "slightly less impossible", and finally to "built a prototype". From my laymans' perspective, it's the trajectory that matters more than the current state-of-the-art.
    - jerf 7y ago
      Not the way I'm using the word. The drive is not currently merely like an airplane, where it is obviously possible to fly (at least as well as birds), we just didn't know how to bang the rocks together correctly to do it. The Alcubierre drives requires things that we have every reason to believe are impossible. In English the term "negative mass" may just seem like, oh, someday maybe we'll advance and have this; in math, it's even worse than you may think I'm going to say. It isn't that we don't know what "negative mass" is. It in fact already appears in some of our equations. The problem is that the product of negative mass times the amount of time it exists seems to be fairly sharply bounded at literally dozens of orders of magnitude too small to conceivably be of any use. We have every reason to believe that stable negative mass is impossible. Not just "we don't know how to do it yet", but impossible. Impossible is like "perfect"; technically, it doesn't admit of "degrees" of impossible. So moving from "impossible" to "impossible" is not progress. People like to cite a lot of cases of various supposed boundaries being broken over time as evidence that maybe this one will be broken too, but there's a qualitative difference between some "elderly distinguished scientist" opining something is impossible, and the mathematics of physics saying something is impossible. It is not a sophisticated, open-minded position about the technological possibilities of the future to say that someday, man will break the barriers of the laws of thermodynamics and someday produce the perpetual motion machine; it is ignorance and scientific illiteracy. FTL is not quite that certain yet, but at the moment, the smart money is on it being the exact same sort of thing, not humanity someday overcoming it. At the moment I'd say that if you properly understand the science of the matter and just how thoroughly reality seems to stymie us in our every attempt to worm around the speed of light restriction, you are completely unjustified in giving even a .1% chance of FTL being possible, let alone that humanity will ever achieve it. It looks to be a lot closer to perpetual motion than breaking the sound "barrier", which barely even deserves the same English word as the speed of light barrier given their massive qualitative differences. Now, as I say, the long shots sometimes pay off, so I don't advocate that nobody thinks about this. Even the process of discovering why the <.1% is better thought of as a flat 0% can be valuable scientific progress, plus there is always the chance I'm wrong. However, at the moment, it looks like FTL is a problem that is far harder than just waving a couple of hoary old quotes about scientists at it is going to solve. You're not fighting "scientists", but the math. Personally, I tend to think Hawking probably got it right with his chronology protection conjecture, and that even if you do manage to build something that goes faster than light or travels back in time, the entire system will literally explode. FTL may not be just impossible because we don't know how to build it, but because it really is fundamentally impossible; spacetime will literally explode in your face even if you do manage it. https://en.wikipedia.org/wiki/Chronology_protection_conjecture https://en.wikipedia.org/wiki/Chronology_protection_conjectu...
- pingyong 7y ago
  Honestly the amount doesn't even matter. If we could make a baseball amount of negative energy but needed a Jupiter amount, sure, that looks solvable. But we don't even know if it's theoretically possible to create a baseball amount of negative energy. As long as that question hasn't been answered, any discussion about practical applications seems rather pointless.
baja_blast 7y ago
There has been some experimental progress for negative mass from Bose-Einstein condensate https://en.wikipedia.org/wiki/Negative_mass https://en.wikipedia.org/wiki/Negative_mass to some interesting potential properties of future meta materials.

contravariant 7y ago

I think it's always been taken somewhat seriously from the start of general relativity (it didn't take long before the first formal description of a wormhole). The discovery of gravitational waves has again provided strong proof in favour of general relativity, but I don't think this is what is preventing people from seriously considering warp drives. Until a way is found to remove the need for exotic matter or to generate exotic matter it remains a purely theoretical exercise.

qubex 7y ago
The problem isn’t really the need for exotic matter in enormous quantities (apparently we have a negatively curved universe where dark energy serves exactly that purpose), but rather the aspect of causal disconnection: everything inside the bubble is disconnected from everything outside it, so it’s difficult to envision how the spacecraft inside could be generating, steering, or even shutting down the warp bubble outside itself.

honoredb 7y ago

Typo near the beginning, "press a petal," gave me a fascinating mental image for a second. I'm sure it'll be informative to learn exactly why every theoretical avenue for faster-than-light travel doesn't work, but I feel like we can infer from the size of the universe that these effects don't exist; if they did, they'd dominate our observations of the universe and we'd never have thought the speed of light was a fundamental limit in the first place.

nateferrero 7y ago
Flower petals would make an amazing tactile controller

Vysero 7y ago

Sounds to me like they are discussing tech that may exist 5 to 6 hundred years from now... not really worthy of their attention imo.

pluto9 7y ago
For it to exist 500 years from now, someone will have to work on it for the next 500 years.
- Vysero 7y ago
  That's not true. What it would take is a massive advance in material science or what-have-you. Once that massive advance happens then it may or may not make this tech possible. However, that massive advance will most likely have nothing to do with working on this particular tech in the meantime.

mellosouls 7y ago

Scientists Are Starting to Take Warp Drives Seriously No they aren't. This is just a fluff piece for a highly speculative but excitingly sci-fi sounding propulsion mechanism with not even the remotest prospect of practical implementation. See also EM Drive, etc.

deleted 7y ago
[deleted]
hhas01 7y ago
Never mind implementation; what about causality? https://en.wikipedia.org/wiki/Causality_(physics) https://en.wikipedia.org/wiki/Causality_(physics) Anyone who wants to build a warp drive has to start by proving Einstein wrong. Anything else is a scam.
- rootbear 7y ago
  Yes, this is my problem with such “warp drive” articles. They rarely address the causality issues with ALL forms of FTL travel.
- alfromspace 7y ago
  How does FTL violate causality? I've tried reading on it before but didn't understand it with my casual understanding of physics.
  - shadowgovt 7y ago
    This website explains it much better than I can, but the tl;dr explanation is there's no "privileged frame of reference" in relativity. Even if two frames of reference can be arranged to agree on a causal sequence involving FTL phenomena, a third observer can be constructed that perceives the sequence of events happening out of order; they get the light from effect before they get the light from cause. This creates nasty phenomena that we don't seem to observe in nature (i.e. if the third party observes effect before cause, they can interfere with cause. Everyone loves a good temporal paradox ;) ). http://www.physicsmatt.com/blog/2016/8/25/why-ftl-implies-time-travel http://www.physicsmatt.com/blog/2016/8/25/why-ftl-implies-ti...

tjchear 7y ago

I've heard often about how the energy estimate for warp drive has been revised down from the mass of the universe to that of Jupiter. Forgive my ignorance, but is this just a matter of refining the shape of the warp around a spaceship, or is it something else? What would it take to further drive down that theoretical energy requirement? Is there a trade-off being considered here?

qubex 7y ago
It is the result of refining the geometry of the warp bubble to be generated by two toroids rather than a single ring, inflating the interior compared to the external perception thereof (a la Tardis), and most critically, by oscillating the field.

mnky9800n 7y ago

sciencealert is starting to post non-clickbait articles. wait no they aren't. lol.

ptah 7y ago

how is this different from aether https://en.wikipedia.org/wiki/Aether_theories https://en.wikipedia.org/wiki/Aether_theories

juped 7y ago
Using "aether" as a generalized snarl word is really irksome. None of us were alive for the debates in physics of a century ago. General relativity is an aether theory; i.e., it ascribes properties (the metric tensor) to empty space. Appeal to authority below since that's the level we're playing on when we misuse dated terminology like this. "We may say that according to the general theory of relativity space is endowed with physical qualities; in this sense, therefore, there exists an ether. According to the general theory of relativity space without ether is unthinkable; for in such space there not only would be no propagation of light, but also no possibility of existence for standards of space and time (measuring-rods and clocks), nor therefore any space-time intervals in the physical sense." -- Albert Einstein
- ptah 7y ago
  sorry, i was just curious. i didn't know people felt that strongly about it
- taylodl 7y ago
  Don't confuse the model with reality. The interesting thing about GR and its stress-energy tensor is you can't distinguish the model from the reality. The model says space is curved and it's this curvature which we perceive as gravity. Does that mean space is actually curved? No. But we have no way to tell. It's a fascinating concept when you think about it. Quantum gravity may give us a way out but so far we've achieved little progress, mainly due to the very same stress-energy tensor being a different type than those found in other quantum fields. Viktor Roth provides a simple explanation of the problem: https://www.forbes.com/sites/quora/2017/05/17/the-marriage-of-einsteins-theory-of-relativity-and-quantum-physics-depends-on-the-pull-of-gravity/#65399968e3a6 https://www.forbes.com/sites/quora/2017/05/17/the-marriage-o.... If you're into physics Viktor is a fun guy to follow on Quora.
7y ago

34679 7y ago

>Please don't post shallow dismissals, especially of other people's work. A good critical comment teaches us something. https://news.ycombinator.com/newsguidelines.html https://news.ycombinator.com/newsguidelines.html Just a reminder.

reportgunner 7y ago

If you like the idea of Alcubierre Drive, give Elite: Dangerous a try - every ship (that is not a fighter) has an Alcubierre Drive installed and you use it extensively to get around "The bubble" (a sphere of inhabited space roughly 20 light years with Earth as its centre) and even beyond. I have no affiliation with Elite: Dangerous, that's just how I learned about Alcubierre Drive

diegoperini 7y ago

"Scientists" is not single community of converging opinions. "Scientists" do not even agree on how serious the climate change is. Prefixing these kind of titles with "Some" (as in "Some Scientists...") may seem redundant but it actually gives an entirely different message which I believe is almost always important to be explicit about.

unknownkadath 7y ago

I feel really bad for this undergrad; The student's advisor did not do him any favors by letting him go and give this talk to the IEEE. It is perfect material for clickbait farms and the wider krank-net. If you can access it, the doi link to the conference paper is: doi.org/10.2514/6.2019-4288 This is not a serious attempt, and in no way indicates that scientists are starting to "take warp drives seriously." It is pitching that same silly stuff White et al have been promising is "real close now" for around 15 years. I also cringed at the equations and figures that were obviously copy/pasted from White's PDFs to Word and back. Having this kind of kooky thing hanging from a baby undergraduate's name--a name that I'm not going to propagate on the web for his own good--is not going to help his future career, and everyone involved should feel bad for wasting his time. Sorry this is boiling my grits so badly, am I over reacting or is this awful?