17 ms·

NASA confirms that the ‘impossible’ EmDrive thruster really works

198 points by fahimulhaq 11y ago

Pyxl101 11y ago
Very interesting. I've been following this in the news for some time, hoping to learn the results of the latest research. In previous tests it seemed like the significance of the effect was diminishing on each iteration, suggesting it might be experimental error. Anyone have a handle on how the latest results have changed? I don't get a good sense from the article.
- threeseed 11y ago
  The purpose was to reduce the Lorentz force interactions: 1) Built and installed a 2nd generation, closed face magnetic damper that reduced the stray magnetic fields in the vacuum chamber by at least an order of magnitude and any Lorentz force interactions it could produce. 2) Changed up the torque pendulum's grounding wire scheme and single point ground location to minimize ground loop current interactions with the remaining stray magnetic fields and unbalanced dc currents from the RF amplifier when its turned on. This reduced the Lorentz force interaction to less than 2 micro-Newton (uN) for the dummy load test. 3) Rebuilt the copper frustum test article so that it is now fully integrated with the RF VCO, PLL, 100W RF amp, dual directional coupler, 3-stub tuner and connecting coax cables, then mounted this integrated test article at the opposite end of the torque pendulum, as far away as possible from the 2nd generation magnetic damper where only the required counterbalance weights now reside. Now since they were still seeing 100uN of force that means they have 98uN of force unaccounted for. And the next iteration of the test is trying to mitigate the effect of any thermal forces.
  - gambiting 11y ago
    At which point it would be actually cheaper to put this whole thing in space, turn it on and see if it produces any trust? If it does, then it definitely works. As long as it's on Earth, they will spend forever trying to account for extra variables.
    - JohnBooty 11y ago
      Yeah. The general rule of thumb is that it costs $10,000/pound to put something into orbit. The cost would increase by orders of magnitude once you include all of the other resources needed to track the experiment, but this does seem like a relatively cheap experiment to run in space. http://www.nasa.gov/centers/marshall/news/background/facts/astp.html_prt.htm http://www.nasa.gov/centers/marshall/news/background/facts/a... I think what's preventing this is: 1.) NASA can only run a certain amount of experiments at once and I'm sure there's a long waiting list. If they run this one, something else doesn't run. 2.) Space may not be the extra variable-free environment we're hoping for here: tons of intense electromagnetic activity and so forth.
threeseed 11y ago
They didn't confirm anything. It was merely a rerun of tests with more of the potential background causes mitigated. It is going to require a lot more tests before someone like NASA unequivocally states that this works. Especially given that this device relies on physics we don't yet know about. Worth reading here: http://forum.nasaspaceflight.com/index.php?topic=38577.940 http://forum.nasaspaceflight.com/index.php?topic=38577.940
- Natanael_L 11y ago
  Not much unlike the recent string of Bell tests. Closing one loophole after another until you can feel confident there's no other reasonable explanation left except a single one, the proof or invalidation of the theory you're trying to prove.
  - iofj 11y ago
    Except this is more fun. Like a few other devices before it, the emdrive (claims it) doesn't do what physics predicts it should do, without offering either explanation or theories to replace existing physics. This certainly seems to make a certain class of people very angry, but it's really quite exiting.
  - gus_massa 11y ago
    This is very different from the Bell inequalities. The Bell inequalities is an easy to calculate result of quantum mechanic, the whole calculation is less than 1 page long. (It's not easy to discover, but once Bell discovered it, anyone can check the calculation.) It follows the same rules of all the other QM experiments that have been thoughtfully tested, so it's totally expected to be true. The problem is that it's unintuitive, or to be more clear it's even more unintuitive that the usual QM results. The loopholes were very weird, like: "The PRNG of my computer is conspiring with the PRNG generator of your computer to get the results of the Bell inequality. They can conspire using signals that travel at less than the light speed, so perhaps we have conspiring hidden variables and not QM." So to close the loophole someone has to use a real RNG instead of a PRNG, and be sure that it random. And do the measurements in a short time so the crystal in one site can't conspire with the crystal in the other site, and do the experiments far away so the light doesn't have enough time to travel from one sensor to the other sensor. The loopholes were totally paranoiac loopholes, but to disprove the hidden variables theories you have to close all the loopholes. (I think it's possible to imagine even more weird loopholes, so expect a few linkbait announcement in the next year with the discovery of an insane loophole in the last Bell experiment.) The EM drive breaks the current accepted physics theories if the thrust/energy ratio if greater than 1/c = 3.33 nano-Newtons per Watt. Some of the loopholes are: The electromagnetic force between the wires in the device (it's like an electromagnet, without the iron core, so it's not as strong as a true electromagnet) The force due to thermal effects, like expansion or convection, because the device get really hot when in use. Some of the experiments measure a delay that is expected when you need some time to heat the device and some time to cool the device after use. The problem is that they still are closing the obvious loopholes, not the weird ones. The usual trick is to have a very strong force that is much more than the expected effects of heating and electromagnetic interactions of the wires, but they have measured only a very tiny force.
tdyen 11y ago
So if an EmDrive worked, what would it give us? A star trek impulse drive type thing? Or is it so low level an effect it would be useless?
- Scarblac 11y ago
  Impossible to know without knowing _why_ it works. It's in contradiction with what we currently know of physics (so it's still far, far more likely that NASA eliminates a few more possible outside causes of the tiny measured thrust and the effect disappears), but if it does work then who knows what else could also work.
- colinramsay 11y ago
  The impulse engine in Star Trek was just a fancy fusion-powered plasma rocket. http://memory-alpha.wikia.com/wiki/Impulse_drive http://memory-alpha.wikia.com/wiki/Impulse_drive
  - kuschku 11y ago
    Actually, there are several in-universe articles saying otherwise: The interaction between the shields and a conventional propulsive system would be horrible (you’d get fried in your own plasma). Therefore the Interacting Magnetic Pulse system (sorry, I’m translating back here, so I dunno if that’s the correct term in the correct in-universe article in english) actually uses some weird interaction of microwaves to create "gravitational waves on which the ship then rides", as one engineer said poetically.
- iofj 11y ago
  It would give us one more point of serious divergence between our physics theories and the real world. What would that give us ? Good question. Something between what the discovery of the bandgap in semiconductors got us and what finding out that the speed of sound in cheddar cheese is much more temperature dependent than in brie.
  - physPop 11y ago
dzdt 11y ago
Headline is wrong. Correct topic sentence from article : "In essence, by utilizing an improved experimental procedure, the team managed to mitigate some of the errors from prior tests — yet still found signals of unexplained thrust." No, the EmDrive does not work, they just haven't yet figured out yet why they see the spurious acceleration in their measurements. How do we know it doesn't work? Because it violates conservation of momentum, without involving any of the extreme conditions where our current understanding of physics might break down. Basic physics is REALLY REALLY well tested. The chances that some new experimental configuration will expose new physics, without involving extreme energy concentrations or extremely large or tiny spatial dimensions, is so near to zero as to be negligible.
- mangecoeur 11y ago
  True, but how many clicks would the headline "NASA has not yet eliminated enough errors in its EM Drive experiment to conclusively prove that it doesn't work" have got. But yeah, no one with any understanding of physics is betting money on this thing working.
  - AnimalMuppet 11y ago
    I wouldn't bet more than a nickel that it works. But I wouldn't bet more than $1000 that it doesn't, either. (Disclaimer: I actually wouldn't bet anything either way, but I think the sentiment is right.)
- grovulent 11y ago
  'know it doesn't work' - seems a bit strong here. 1) While a violation of a widely accepted law of nature is indeed unlikely - it's not like it hasn't happened before. 2) There may yet still be some way to model the experimental data that at once makes the em-drive viable, while still preserving conservation of momentum. Still unlikely, but arguably more likely than 1). 3) And while these both remain unlikely - it is yet rational to have an increased credence for them while the experimental data remains unaccounted for. In fact, it's arguable that this increase of credence is significant - for if it were not, performing the necessary experiments to find out either way would be a waste of time. There are of course some very smart domain experts performing these experiments. Your tone and use of the word 'know' implies their irrationality. I would advise greater humility.
hannob 11y ago
Remember the faster-than-light neutrinos? Where they repeated the experiment multiple times with the same result? And nobody could find a plausible explanation for an error? And then, some months later, they found it was just a bad cable. The sane rule of thumb on these kinds of experiments that seem to contradict basic physics is to assume it's just an error in the experiment or the data calculations. Even if they did it multiple times. If this gets replicated by multiple independent teams worldwide with different experiments - then we can talk about new physics. But it's important to understand how extremely unlikely that is. The best you can learn from these kind of stories is how hard it is to get science right and how subtle errors can be. Don't get me wrong: I'd love to see some star-trek-like science becoming real. But it certainly doesn't help to replace critical thinking with wishful thinking.
- shin_lao 11y ago
  Difference here is that the experiment has been done by two different teams from different countries using different protocols.
  - makomk 11y ago
    If I recall correctly, the two teams got different results. Although they both found very small amounts of thrust that they couldn't explain, the actual amount of unexplained thrust was different by something like an order of magnitude.
  - marcosdumay 11y ago
    And no team had a conclusive result.
- Symmetry 11y ago
  I'll agree that experimental error is the most likely explanation by far but I think there's still a noticeable chance that the explanation is some novel effect that doesn't actually violate conservation of momentum. If I were to give a break down on my expectations they'd probably be something like 90% Experimental error 9% Unexpected and novel consequence of current physics 1% New physics that doesn't actually violate momentum conservation ~0% Violation of conservation of momentum. But this has gone the point where even if it's experimental error I expect the mechanism will be at least somewhat interesting, as with the Italian speed of light experiment.
stargazer-3 11y ago
I love that the question of this technology's validity is so grand it can be approached with Fermi's Paradox. If such physics indeed exists, allowing interstellar expansion of life, then it increases our chances of detecting a signature of extraterrestrial life out there. Since we haven't detected anything yet, it seems that EmDrive-tech is less likely to be real than if we would have.
- adrianN 11y ago
  This technology doesn't make interstellar travel much easier, even if it works. You only save reaction mass, but you still need huge amounts of energy. Our best bet currently are nuclear pulse engines [1]. Super advanced civilizations might use Hawking radiation instead [2]. [1] https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propulsion) https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propuls... [2] https://en.wikipedia.org/wiki/Black_hole_starship https://en.wikipedia.org/wiki/Black_hole_starship
selimthegrim 11y ago
I can't name sources, but I have it in good confidence that this man ("Sonny" White) was forced to rewrite his dissertation by his PhD committee (mind you not his advisor, who was old and about to retire and had to be cajoled into line by the rest of them) because his first try was apparently all about this EMDrive stuff. This is a pathology.
- ryanwaggoner 11y ago
  Won't they look pretty stupid if this turns out to be real :) I know, I know, it's not real, it's not how science should be done, blah blah. I'm sure you're right.
- selimthegrim 11y ago
  So, I'm being down voted for stating a relevant fact? I was asked not to reveal this by my source.
  - JoeAltmaier 11y ago
    For disagreement, probably with the final line.
  - mikeash 11y ago
    For stating irrelevant hearsay, perhaps.
    - selimthegrim 11y ago
      What, and if I break confidence and name names from the Rice faculty that would somehow be better? Being forced to rewrite entirely at a defense by the rest of one's committee is a BFD, it absolutely impacts his credibility.
      - mikeash 11y ago
        Without knowing the details of what happened, we have no idea how it affects this person's credibility. You have no credibility, so your unverifiable story conveys zero information. All it does is stir things up. Substantiating the story would be good, and failing that, saying nothing would be better than essentially spreading a rumor.
peter303 11y ago
Cold fusion is the power source too.
ohitsdom 11y ago
A lot of skepticism and negativity here, and I get that. But it's exciting to watch science play out. This could be a huge discovery, or it could be crap. I love seeing the methodology in making each test more and more definitive by reducing variables and outside influences.
snarfy 11y ago
Momentum has velocity, but the velocity of light is the same in all reference frames. It seems like there is a conflict between conservation of momentum and special relativity. From the point of view of the light beam, nothing is moving.
- mercutio2 11y ago
  The speed of light in a vacuum is constant in all reference frames, but a photon's frequency is not constant in all reference frames, so it's momentum (hf/c) is not constant. This is bog-standard special relativity.
  - snarfy 11y ago
    Ah, this makes sense.
- nerd_stuff 11y ago
  Momentum and Special Relativity don't conflict. Momentum is modified with a Lorentz Factor which for a particle with mass runs to infinity as the speed approaches the speed of light. For electromagnetic radiation like light the momentum is a function of the energy, not the velocity.
zellyn 11y ago
Why don't they just put one of these things in space, with solar panels, turn it on, and see what happens? I guess the expense? It does seem the most expedient way to verify whether it works or not.
- swolchok 11y ago
  even SpaceX launches cost over 50 million dollars (https://www.google.com/search?q=spacex+launch+cost https://www.google.com/search?q=spacex+launch+cost has a big pullquote to that effect, for example)
transfire 11y ago
Caution is called for. After all, blowing past warp 5 can damage the space-time continuum.
dandare 11y ago
Can someone please explain to me how does one creates new technology without having alt least one of the following? a) working prototype, b) consistent theory why the new technology will work. In other words, what made Roger Shawyer believe his engine will work if he does not know how should it work nor have a prototype?
jcfrei 11y ago
Previous discussion: https://news.ycombinator.com/item?id=10496638 https://news.ycombinator.com/item?id=10496638
saintgimp 11y ago
Seems like they need to do the hardware equivalent of a "git bisect" here. Instead of fiddling around with the current version of the device, trying to figure out if the observed effect is actually propulsion or just an artifact, someone should start tearing the thing apart, testing as they go, and find out at what point the observed effect goes away. That would probably be instructive.
SFjulie1 11y ago
Economical crisis are recognizable by the fact people tends to announce "infinite energy source", "cheap energy", or "perpetual movement" finally made true. It is very interesting that while NASA that has been a clear "cache nez" during cold war to mask the use of nazis scientists and technologies for the USA they are now having a problem: space programs are considered to costly for their return other investment. Especially when you know the budget of ESA for rosetta/philae mission compared to NASA's budget. Being on the grill, NASA is lobbying for even more costly mission to mars and support their own propaganda (intestallar, alone on mars...). And now, miracle, they have an opportunistic new technology that could help achieve "cheap easy journey" to far away distance. I can't help to be a little suspicious. The timing is so perfect. And as numerous comments are spotting there is no new technology until we can explain the causation. Because that is how science work: experiments should be consistent with theory, and vice-versa. Else this is religion or philosophy. Maybe emDriver could be the proof God exists, but it is not likely. Well, if it existed, and since we would have a physical place where to search I would kill it anyway. I hate Gods, I prefer to drive my own destiny without a "père/mère fouettard(e)" looking upon my shoulder like a stalker.
jrjarrett 11y ago
Woo hoo! The reactionless thruster! Next: Outsider hyperdrive! http://news.larryniven.net/concordance/main.asp?alpha=T#thruster http://news.larryniven.net/concordance/main.asp?alpha=T#thru...
alexandercrohde 11y ago
I almost want to flag this link for playing loud sound advertisements on page load, but I'm not sure that's proper in this community. Is there not a better link to this content?
dredmorbius 11y ago
I'd really like to see @dang et all at HN add digitaltrends.com to the penalised-by-default domains on HN. This is simply irresponsible hackery. Rick Stella as well.

198 points by fahimulhaq 11y ago

Very interesting. I've been following this in the news for some time, hoping to learn the results of the latest research. In previous tests it seemed like the significance of the effect was diminishing on each iteration, suggesting it might be experimental error. Anyone have a handle on how the latest results have changed? I don't get a good sense from the article.

threeseed 11y ago
The purpose was to reduce the Lorentz force interactions: 1) Built and installed a 2nd generation, closed face magnetic damper that reduced the stray magnetic fields in the vacuum chamber by at least an order of magnitude and any Lorentz force interactions it could produce. 2) Changed up the torque pendulum's grounding wire scheme and single point ground location to minimize ground loop current interactions with the remaining stray magnetic fields and unbalanced dc currents from the RF amplifier when its turned on. This reduced the Lorentz force interaction to less than 2 micro-Newton (uN) for the dummy load test. 3) Rebuilt the copper frustum test article so that it is now fully integrated with the RF VCO, PLL, 100W RF amp, dual directional coupler, 3-stub tuner and connecting coax cables, then mounted this integrated test article at the opposite end of the torque pendulum, as far away as possible from the 2nd generation magnetic damper where only the required counterbalance weights now reside. Now since they were still seeing 100uN of force that means they have 98uN of force unaccounted for. And the next iteration of the test is trying to mitigate the effect of any thermal forces.
- gambiting 11y ago
  At which point it would be actually cheaper to put this whole thing in space, turn it on and see if it produces any trust? If it does, then it definitely works. As long as it's on Earth, they will spend forever trying to account for extra variables.
  - JohnBooty 11y ago
    Yeah. The general rule of thumb is that it costs $10,000/pound to put something into orbit. The cost would increase by orders of magnitude once you include all of the other resources needed to track the experiment, but this does seem like a relatively cheap experiment to run in space. http://www.nasa.gov/centers/marshall/news/background/facts/astp.html_prt.htm http://www.nasa.gov/centers/marshall/news/background/facts/a... I think what's preventing this is: 1.) NASA can only run a certain amount of experiments at once and I'm sure there's a long waiting list. If they run this one, something else doesn't run. 2.) Space may not be the extra variable-free environment we're hoping for here: tons of intense electromagnetic activity and so forth.

threeseed 11y ago

They didn't confirm anything. It was merely a rerun of tests with more of the potential background causes mitigated. It is going to require a lot more tests before someone like NASA unequivocally states that this works. Especially given that this device relies on physics we don't yet know about. Worth reading here: http://forum.nasaspaceflight.com/index.php?topic=38577.940 http://forum.nasaspaceflight.com/index.php?topic=38577.940

Natanael_L 11y ago
Not much unlike the recent string of Bell tests. Closing one loophole after another until you can feel confident there's no other reasonable explanation left except a single one, the proof or invalidation of the theory you're trying to prove.
- iofj 11y ago
  Except this is more fun. Like a few other devices before it, the emdrive (claims it) doesn't do what physics predicts it should do, without offering either explanation or theories to replace existing physics. This certainly seems to make a certain class of people very angry, but it's really quite exiting.
- gus_massa 11y ago
  This is very different from the Bell inequalities. The Bell inequalities is an easy to calculate result of quantum mechanic, the whole calculation is less than 1 page long. (It's not easy to discover, but once Bell discovered it, anyone can check the calculation.) It follows the same rules of all the other QM experiments that have been thoughtfully tested, so it's totally expected to be true. The problem is that it's unintuitive, or to be more clear it's even more unintuitive that the usual QM results. The loopholes were very weird, like: "The PRNG of my computer is conspiring with the PRNG generator of your computer to get the results of the Bell inequality. They can conspire using signals that travel at less than the light speed, so perhaps we have conspiring hidden variables and not QM." So to close the loophole someone has to use a real RNG instead of a PRNG, and be sure that it random. And do the measurements in a short time so the crystal in one site can't conspire with the crystal in the other site, and do the experiments far away so the light doesn't have enough time to travel from one sensor to the other sensor. The loopholes were totally paranoiac loopholes, but to disprove the hidden variables theories you have to close all the loopholes. (I think it's possible to imagine even more weird loopholes, so expect a few linkbait announcement in the next year with the discovery of an insane loophole in the last Bell experiment.) The EM drive breaks the current accepted physics theories if the thrust/energy ratio if greater than 1/c = 3.33 nano-Newtons per Watt. Some of the loopholes are: The electromagnetic force between the wires in the device (it's like an electromagnet, without the iron core, so it's not as strong as a true electromagnet) The force due to thermal effects, like expansion or convection, because the device get really hot when in use. Some of the experiments measure a delay that is expected when you need some time to heat the device and some time to cool the device after use. The problem is that they still are closing the obvious loopholes, not the weird ones. The usual trick is to have a very strong force that is much more than the expected effects of heating and electromagnetic interactions of the wires, but they have measured only a very tiny force.

tdyen 11y ago

So if an EmDrive worked, what would it give us? A star trek impulse drive type thing? Or is it so low level an effect it would be useless?

Scarblac 11y ago
Impossible to know without knowing _why_ it works. It's in contradiction with what we currently know of physics (so it's still far, far more likely that NASA eliminates a few more possible outside causes of the tiny measured thrust and the effect disappears), but if it does work then who knows what else could also work.
colinramsay 11y ago
The impulse engine in Star Trek was just a fancy fusion-powered plasma rocket. http://memory-alpha.wikia.com/wiki/Impulse_drive http://memory-alpha.wikia.com/wiki/Impulse_drive
- kuschku 11y ago
  Actually, there are several in-universe articles saying otherwise: The interaction between the shields and a conventional propulsive system would be horrible (you’d get fried in your own plasma). Therefore the Interacting Magnetic Pulse system (sorry, I’m translating back here, so I dunno if that’s the correct term in the correct in-universe article in english) actually uses some weird interaction of microwaves to create "gravitational waves on which the ship then rides", as one engineer said poetically.
iofj 11y ago
It would give us one more point of serious divergence between our physics theories and the real world. What would that give us ? Good question. Something between what the discovery of the bandgap in semiconductors got us and what finding out that the speed of sound in cheddar cheese is much more temperature dependent than in brie.
- physPop 11y ago

dzdt 11y ago

Headline is wrong. Correct topic sentence from article : "In essence, by utilizing an improved experimental procedure, the team managed to mitigate some of the errors from prior tests — yet still found signals of unexplained thrust." No, the EmDrive does not work, they just haven't yet figured out yet why they see the spurious acceleration in their measurements. How do we know it doesn't work? Because it violates conservation of momentum, without involving any of the extreme conditions where our current understanding of physics might break down. Basic physics is REALLY REALLY well tested. The chances that some new experimental configuration will expose new physics, without involving extreme energy concentrations or extremely large or tiny spatial dimensions, is so near to zero as to be negligible.

mangecoeur 11y ago
True, but how many clicks would the headline "NASA has not yet eliminated enough errors in its EM Drive experiment to conclusively prove that it doesn't work" have got. But yeah, no one with any understanding of physics is betting money on this thing working.
- AnimalMuppet 11y ago
  I wouldn't bet more than a nickel that it works. But I wouldn't bet more than $1000 that it doesn't, either. (Disclaimer: I actually wouldn't bet anything either way, but I think the sentiment is right.)
grovulent 11y ago
'know it doesn't work' - seems a bit strong here. 1) While a violation of a widely accepted law of nature is indeed unlikely - it's not like it hasn't happened before. 2) There may yet still be some way to model the experimental data that at once makes the em-drive viable, while still preserving conservation of momentum. Still unlikely, but arguably more likely than 1). 3) And while these both remain unlikely - it is yet rational to have an increased credence for them while the experimental data remains unaccounted for. In fact, it's arguable that this increase of credence is significant - for if it were not, performing the necessary experiments to find out either way would be a waste of time. There are of course some very smart domain experts performing these experiments. Your tone and use of the word 'know' implies their irrationality. I would advise greater humility.

hannob 11y ago

Remember the faster-than-light neutrinos? Where they repeated the experiment multiple times with the same result? And nobody could find a plausible explanation for an error? And then, some months later, they found it was just a bad cable. The sane rule of thumb on these kinds of experiments that seem to contradict basic physics is to assume it's just an error in the experiment or the data calculations. Even if they did it multiple times. If this gets replicated by multiple independent teams worldwide with different experiments - then we can talk about new physics. But it's important to understand how extremely unlikely that is. The best you can learn from these kind of stories is how hard it is to get science right and how subtle errors can be. Don't get me wrong: I'd love to see some star-trek-like science becoming real. But it certainly doesn't help to replace critical thinking with wishful thinking.

shin_lao 11y ago
Difference here is that the experiment has been done by two different teams from different countries using different protocols.
- makomk 11y ago
  If I recall correctly, the two teams got different results. Although they both found very small amounts of thrust that they couldn't explain, the actual amount of unexplained thrust was different by something like an order of magnitude.
- marcosdumay 11y ago
  And no team had a conclusive result.
Symmetry 11y ago
I'll agree that experimental error is the most likely explanation by far but I think there's still a noticeable chance that the explanation is some novel effect that doesn't actually violate conservation of momentum. If I were to give a break down on my expectations they'd probably be something like 90% Experimental error 9% Unexpected and novel consequence of current physics 1% New physics that doesn't actually violate momentum conservation ~0% Violation of conservation of momentum. But this has gone the point where even if it's experimental error I expect the mechanism will be at least somewhat interesting, as with the Italian speed of light experiment.

stargazer-3 11y ago

I love that the question of this technology's validity is so grand it can be approached with Fermi's Paradox. If such physics indeed exists, allowing interstellar expansion of life, then it increases our chances of detecting a signature of extraterrestrial life out there. Since we haven't detected anything yet, it seems that EmDrive-tech is less likely to be real than if we would have.

adrianN 11y ago
This technology doesn't make interstellar travel much easier, even if it works. You only save reaction mass, but you still need huge amounts of energy. Our best bet currently are nuclear pulse engines [1]. Super advanced civilizations might use Hawking radiation instead [2]. [1] https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propulsion) https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propuls... [2] https://en.wikipedia.org/wiki/Black_hole_starship https://en.wikipedia.org/wiki/Black_hole_starship

selimthegrim 11y ago

I can't name sources, but I have it in good confidence that this man ("Sonny" White) was forced to rewrite his dissertation by his PhD committee (mind you not his advisor, who was old and about to retire and had to be cajoled into line by the rest of them) because his first try was apparently all about this EMDrive stuff. This is a pathology.

ryanwaggoner 11y ago
Won't they look pretty stupid if this turns out to be real :) I know, I know, it's not real, it's not how science should be done, blah blah. I'm sure you're right.
selimthegrim 11y ago
So, I'm being down voted for stating a relevant fact? I was asked not to reveal this by my source.
- JoeAltmaier 11y ago
  For disagreement, probably with the final line.
- mikeash 11y ago
  For stating irrelevant hearsay, perhaps.
  - selimthegrim 11y ago
    What, and if I break confidence and name names from the Rice faculty that would somehow be better? Being forced to rewrite entirely at a defense by the rest of one's committee is a BFD, it absolutely impacts his credibility.
    - mikeash 11y ago
      Without knowing the details of what happened, we have no idea how it affects this person's credibility. You have no credibility, so your unverifiable story conveys zero information. All it does is stir things up. Substantiating the story would be good, and failing that, saying nothing would be better than essentially spreading a rumor.

peter303 11y ago

Cold fusion is the power source too.

ohitsdom 11y ago

A lot of skepticism and negativity here, and I get that. But it's exciting to watch science play out. This could be a huge discovery, or it could be crap. I love seeing the methodology in making each test more and more definitive by reducing variables and outside influences.

snarfy 11y ago

Momentum has velocity, but the velocity of light is the same in all reference frames. It seems like there is a conflict between conservation of momentum and special relativity. From the point of view of the light beam, nothing is moving.

mercutio2 11y ago
The speed of light in a vacuum is constant in all reference frames, but a photon's frequency is not constant in all reference frames, so it's momentum (hf/c) is not constant. This is bog-standard special relativity.
- snarfy 11y ago
  Ah, this makes sense.
nerd_stuff 11y ago
Momentum and Special Relativity don't conflict. Momentum is modified with a Lorentz Factor which for a particle with mass runs to infinity as the speed approaches the speed of light. For electromagnetic radiation like light the momentum is a function of the energy, not the velocity.

zellyn 11y ago

Why don't they just put one of these things in space, with solar panels, turn it on, and see what happens? I guess the expense? It does seem the most expedient way to verify whether it works or not.

swolchok 11y ago
even SpaceX launches cost over 50 million dollars (https://www.google.com/search?q=spacex+launch+cost https://www.google.com/search?q=spacex+launch+cost has a big pullquote to that effect, for example)

transfire 11y ago

Caution is called for. After all, blowing past warp 5 can damage the space-time continuum.

dandare 11y ago

Can someone please explain to me how does one creates new technology without having alt least one of the following? a) working prototype, b) consistent theory why the new technology will work. In other words, what made Roger Shawyer believe his engine will work if he does not know how should it work nor have a prototype?

jcfrei 11y ago

Previous discussion: https://news.ycombinator.com/item?id=10496638 https://news.ycombinator.com/item?id=10496638

saintgimp 11y ago

Seems like they need to do the hardware equivalent of a "git bisect" here. Instead of fiddling around with the current version of the device, trying to figure out if the observed effect is actually propulsion or just an artifact, someone should start tearing the thing apart, testing as they go, and find out at what point the observed effect goes away. That would probably be instructive.

SFjulie1 11y ago

Economical crisis are recognizable by the fact people tends to announce "infinite energy source", "cheap energy", or "perpetual movement" finally made true. It is very interesting that while NASA that has been a clear "cache nez" during cold war to mask the use of nazis scientists and technologies for the USA they are now having a problem: space programs are considered to costly for their return other investment. Especially when you know the budget of ESA for rosetta/philae mission compared to NASA's budget. Being on the grill, NASA is lobbying for even more costly mission to mars and support their own propaganda (intestallar, alone on mars...). And now, miracle, they have an opportunistic new technology that could help achieve "cheap easy journey" to far away distance. I can't help to be a little suspicious. The timing is so perfect. And as numerous comments are spotting there is no new technology until we can explain the causation. Because that is how science work: experiments should be consistent with theory, and vice-versa. Else this is religion or philosophy. Maybe emDriver could be the proof God exists, but it is not likely. Well, if it existed, and since we would have a physical place where to search I would kill it anyway. I hate Gods, I prefer to drive my own destiny without a "père/mère fouettard(e)" looking upon my shoulder like a stalker.

jrjarrett 11y ago

Woo hoo! The reactionless thruster! Next: Outsider hyperdrive! http://news.larryniven.net/concordance/main.asp?alpha=T#thruster http://news.larryniven.net/concordance/main.asp?alpha=T#thru...

alexandercrohde 11y ago

I almost want to flag this link for playing loud sound advertisements on page load, but I'm not sure that's proper in this community. Is there not a better link to this content?

dredmorbius 11y ago

I'd really like to see @dang et all at HN add digitaltrends.com to the penalised-by-default domains on HN. This is simply irresponsible hackery. Rick Stella as well.