17 ms·

What we know about the EmDrive and Cannae Drive

208 points by curtis 12y ago

ComputerGuru 12y ago
I'm not a physicist but as someone that's always looked at over-the-top headlines and groaned while internally wishing they were true, I just want to say: this is all so very cool and I'm so excited to see where this takes us. Even if it's not the start of a Star Trek-eseque future, this is some pretty neat stuff and I'm really anxious to hear more about what new gates of knowledge this unlocks. The plot line is right out of sci-fi and it's what makes me love technology so much: we truly never know what we will find.
- aetherson 12y ago
  Understand that the most likely gate of knowledge that this unlocks is, "oh, there was some kind of magnetic interaction between the test drive and the harness," or something to that effect. The proper Bayesian approach to these tests is to downgrade your prior of "drives require reaction mass" from 99.99999999% to 99.999999%
  - kristjankalm 12y ago
    exactly -- I'd guess not too many non-physicits realise what's a prior for 'conservation of momentum violated'
- kristjankalm 12y ago
  the problem is that the excitement is generated by the use of exotic terminology. you wouldn't get excited if a single study reported that alzheimer's was reversed by copious praying and sprinkling of holy water.
binalpatel 12y ago
I know it's unlikely that the EmDrive is real, and even more unlikely that the "warp drive" effects that some have been talking about are real. But...I really hope they are. What a world it'd be if these things prove out to be real.
- higherpurpose 12y ago
  I think even if it proves real, it would still take around 50 years to put in flying cars and such. But perhaps a bit less for using it in satellites. Still it's not too long on the humanity scale of time.
  - astrodust 12y ago
    Why would it take fifty years? This isn' the 1800s where it takes a half century for flush toilets to catch on. We're in an era where things go from laboratory to ubiquitous inside of a decade.
    - mahranch 12y ago
      This is less like flush toilets and more like computers. It took nearly 50 years for the first computers to sit in consumer's home offices. It took time for the technology to be miniaturized and cheap enough to make its way to consumer electronics. Or even cell phones. We were using radio signals in hand held devices for nearly 50 years before a vast majority of consumers were walking around with phones in their pockets in the mid to late 90s. Sure, there were early adopters in the late 80s and early 90s, but the technology was still expensive. And the technology (like walkie talkies) had existed for decades before...
      - danielweber 12y ago
        If this were proven true, there would be a completely manic gold-rush of capital into the area. Flying cars that operate at less than 1/10th the energy of cars on the road now? This would very quickly move from "let's wait for NASA to do more tests" to "let's beat NASA to the test." That's all assuming it's real, of course. I'd bet against it.
        ZoFreX 12y ago
        Who says this will use less energy? The remarkable property of it is the (seeming) violation of conservation of momentum, not its efficiency.
Steuard 12y ago
This is not worth getting excited about. Really. Extraordinary claims require extraordinary evidence. These drives would violate conservation of momentum.[0] Conservation of momentum is built in to the known laws of physics at an extraordinarily deep level. It is obviously not impossible that our known laws are wrong, but the alternative would be to somehow produce a radically different set of physical laws that nevertheless reproduce every test of existing theory to high precision (as much as 14 digits of accuracy in some cases). And you probably also need to explain why the existing theory worked so very well if its bedrock foundation doesn't describe our universe. So really, don't get excited. And don't send these folks money that could do real good elsewhere until they give at least some small reason to expect that it's not a wild goose chase. (Edit to add: I wish this were real, too. With all my heart. But it's not a realistic wish.) [Re-edited to cut some less-appropriate phrasing.] [0] Yes, I know the EmDrive site FAQ (http://emdrive.com/faq.html http://emdrive.com/faq.html) claims that it doesn't violate conservation of momentum. The explanation of why it doesn't actually indicates that it does: "The electromagnetic wave momentum is built up in the resonating cavity, and is transferred to the end walls upon reflection." But the wave's momentum has to come from somewhere, too. So either this is just equivalent to a photon drive (propelled by shooting light out the back), or their device is pulling momentum out of nowhere.
- Tossrock 12y ago
  Why isn't it worth getting excited about? I get excited about lunch. It costs me nothing to follow the progress on low-probability, high impact technological advancements (see: space elevators, commercial fusion power, etc)
  - Steuard 12y ago
    I guess this is really the point: space elevators and commercial fusion are many, many orders of magnitude more likely to pan out than this is. Both of those are engineering challenges, and materials science challenges. They may be insurmountable ones, or they may not. But neither one would unconditionally require changes to the bedrock principles of physics. Human beings are not good at distinguishing between levels of "very low probability". Getting excited about space elevators is awesome, even though we're awfully unlikely to see them in our lifetimes and they might never pan out. But these drive theories are pretty literally too good to be true.
tlb 12y ago
1 micronewton / watt is a surprising amount of thrust. The implied velocity of whatever it's pushing against is 1e6 m/s, which is 1/300 the speed of light.
- hliyan 12y ago
  How does one calculate this?
  - TheLoneWolfling 12y ago
    (1 micronewton / watt)^-1 Units cancel out to give m/s. This is just specific impulse. Though Isp is generally measured in seconds (implied gravitational field of the Earth gives s * m/s/s = m/s.)
- heliumcraft 12y ago
  isn't that super low? if 1 micronewton = 1 newton * 10^-6 then to push against 1kg it would require 1.000 MWatts?
  - tlb 12y ago
    Super-low compared to pushing against matter. But 300x higher than pushing against photons.
    - TheLoneWolfling 12y ago
      Not to mention you don't have a high-powered beam of photons cooking everything behind you.
- MertsA 12y ago
  What's more surprising is that every number I've seen for the higher power Chinese test was 750 milinewtons for 2.5kw of power. That's 300 micronewtons per watt of power.
  - 12y ago
railgun2space 12y ago
Can such a drive be built at home? Would be a wonderful maker pet project.
- ivanb 12y ago
  Easily. Here is one created by a Russian guy https://youtu.be/vcaOKX7Ko7w https://youtu.be/vcaOKX7Ko7w
digitalzombie 12y ago
Sweet. Best case, we get a new awesome thrusters. Worst case, we get the learn new things. So far these drives have pass tests and stumped experts and researchers. So even if it doesn't violate the current laws of physic, it'll paint a better picture of the current laws of physic and better testing method in the future.
- issa 12y ago
  This is exactly my attitude. I'm shocked that people don't think twice about spending money on frivolous or even harmful things, but balk at the idea of paying for pure research.
  - Retra 12y ago
    You don't want to shovel fuel into a crackpot industry. That actually prevents real science from being done.
    - Intermernet 12y ago
      Being snarky, but a lot of the world's consumer economy can be seen as shoveling fuel at crackpot industries. You're correct, but I'd rather a few million dollars going to this research than a few million dollars going to some magnetic-healing-band toting pseudo-guru. The "first world" wastes ridiculous amounts of money every second. Can we divert at least some of it to disproving crack-pot scientific ideas? It'd at least be entertaining (like Mythbusters on steroids!).
    - issa 12y ago
      This isn't an example of a "crackpot" theory. Everyone seems to agree that SOMETHING is happening. Even if the explanation is simply known-physics (which is overwhelmingly likely) there is still value in solving the mystery.
wbhart 12y ago
Comparing the Chinese results with the American results, it seems that raising the wattage by a factor of 50 raises the thrust by a factor of 15000. That's somewhat hard to believe. On the other hand, the linked pdf from the Chinese team suggests that at just 3 times the wattage of the American group, they got 1500 times the thrust. I think there is some confusion somewhere.
- Tossrock 12y ago
  It seems like an impossibly basic mistake, but confusing micro- and milli- newtons would make the math a lot more reasonable.
  - Bud 12y ago
    Not impossibly basic at all. Space missions have failed because of these kinds of basic math errors: http://www.wired.com/2010/11/1110mars-climate-observer-report/ http://www.wired.com/2010/11/1110mars-climate-observer-repor...
    - oldmanjay 12y ago
      I almost want another failure so people will stop pulling this out as an all-purpose rhetorical showstopper.
- waterlesscloud 12y ago
  Well, the natural world is full of non-linear and/or discontinuous responses, so it's not crazy if there's some sort of threshold at work. But yeah, it's more likely there's some confusion in there.
  - wbhart 12y ago
    It's an important question because the article claims "The applications for a device that functions as these appear to would basically replace every form of transportation and thrust invented by humans to date. Such a device would easily be used to make cars, planes, bikes, boats, etc., all more efficient, clean, and cheap." Given that the thrust required for a car would be something like 40,000N, unless the device scales far better than linearly, you'll need a 25GW power station in your car to even make it go.
narrator 12y ago
I think this technology, if real, should be shut down and controlled by the government. Officially, it should be denied and declared to be quackery. It would likely cause grave security problems. Just think of the capabilities this would give the bad guys. We already went too far with technology with the discovery of nuclear weapons and enormous effort has been invested in controlling that technology for decades. The whole reason we went into Iraq was to prevent them from getting technology (WMDs) that we think they shouldn't have access to. I don't think humanity will be ready for this kind of technology until we have elevated our civilization to a "higher level".
- heliumcraft 12y ago
  > to prevent them from getting technology (WMDs) WMDs = pretext, real reason: Oil and GeoPolitical
- astrodust 12y ago
  The irony of your misinformed statement is that the alleged WMDs were American made and sold to Iraq. The classic quote from the time "We know they have WMDs because we have the receipts!"
  - lotsofmangos 12y ago
    Hey, don't forget the British. We tried to build them that super-gun thingy.
- narrator 12y ago
  Hmm.. I was hoping somebody would write a well reasoned response to why this point of view is wrong so I could reasonably change my mind. Well at least I got it out there, even if I had to sacrifice karma.
hooo 12y ago
I'd really like this to be real. I think they need to precisely measure the mass of the whole device before and after the experiment, to make sure the thrust isn't coming from ionization or some decay.
- TheLoneWolfling 12y ago
  They also need to check their vacuum. There's a whole lot of power being thrown around inside those boxes.
nsxwolf 12y ago
As far as I have seen, NASA hasn't actually said anything about this. Is the story even real?
mrfusion 12y ago
If (big IF) this turned out to be real, could we use these on helicopters instead of blades? Or are blades more efficient? Also would it make the hoverboard feasible, or does it require way too much energy?
- indrax 12y ago
  Blades are much more efficient. I've done some back of the napkin estimates that this would levitate if paired with lockheed's supposed small fusion reactor. (and works at all, and if the drive reaches improvements that one paper thought possible, and if it scales with power input, and ....) This inefficiency would still be great in space because you don't have to carry reaction mass with you. (and hovering on earth would mean sustained 1g acceleration in space, which is fantastic.) But if you're swimming through reaction mass anyway, then just push it as efficiently as possible.
MCRed 12y ago
I've some direct experience with a similar situation. I can speak to the issue of "why hasn't spaceX or other major company experimented with this". During the "Cold Fusion" era, when Pons & Fleishman had claimed to develop room temperature fusion, I worked for a major US lab doing superconductor research. (We invented the first superconductors that operated at liquid nitrogen temperatures-- Y1B2C3O) While fusion isn't our area of investigation we, being physicists, were curious. We managed to get our hands on a pre-print of the Pons & Fleishman study and did our own experiments. We kept this very hush hush. We didn't want it getting out that we were doing the experiments or people would claim that we replicated them. So, I believe that SpaceX and other companies are experimenting with this, and if they found good results (as the eagle works tests imply they would) they would continue to do so, but in secret.) We eventually published our paper because we constructed a novel experiment that disproved the P&F observation, from our perspective. None-the-less, true to our fears, this was later reported by "Mondo 2000" (The "arse technica" crossed with WIRED of the day) that we had "confirmed cold fusion is real!!1!1". The letter to the editor I wrote and got our most eminent physicist to sign was never printed by the magazine (IIRC). When you get to the fringes-- that's where the action is-- but it's also where you can have confusing or odd results. And even 30 years ago the media was not trustworthy enough to reveal these results to. Our paper was published in a journal, and yet the media still mis represented the results.
- ableal 12y ago
  Wishful thinking, if not base motives, overpowers most common sense. This seems to be about "reaction-less drives" - I remember reading about how hard-headed SF editor J.W.Campbell had a weak spot for such devices, several decades ago. He entertained a few demos, if memory serves. Didn't pan out then, probably won't now.
- drzaiusapelord 12y ago
  This is one of the many reasons why I consider all "fururist" media as just sci-fi wish fulfillment for kiddies. Its just incredible how unreadable /r/futurology is, for example. Its just a lot of pats on the back about some amazing life-changing technology, that is eternally 10 years away. I don't have access to the Mondo 2000 stuff today, but if any of that was to believed we'd have AI masterminded rockets to moon condos and eternal life by now. The big advances were actually missed as things like interchangable and standardized protocols, power saving SoCs, incremental battery improvements, touchscreens, and fast networks are "boring" compared to spacetravel and robots and such. I feel I'm also seeing the same hype train today with VR, which has unsolved major issues like motion sickness and questionable applications in gaming, let alone anywhere else. To a lesser extent I see the same thing with electric cars that are always somehow 2-3 years from affordability and economic and range parity with ICE cars. These 2-3 years keep blowing past us, but there's no 200 mile range $20,000 car yet, if there will ever be. Its a shame that practical and real advances are often "boring" to the typical sci-fi obsessed INTJ males who dominate science on the internet. I see so much spilled ink about SpaceX and very little about the upcoming SLS and its planned pioneering manned missions or NASA's robotic and science missions, which are all mindblowingly amazing to me. Sadly, this has all become politicized in the most asinine way possible with a dedicated libertarian group on the web voicing this private vs public rivalry to attack NASA, which is ironic as SpaceX is more or less a welfare program of NASA and the US taxpayers. I hope this fad doesn't last long and good science, real breakthroughs, and the largely unpredictable and usually unsexy, in terms of whiz bang space operas, future continues to unfold before us in a wonderful way. The SLS will have us on an asteroid with just boring old chemical rockets, while the futurists continue to sell snake oil to the low information true believers and diminish the amazing and real accomplishments of the day. "Everything's amazing and nobody's happy." - Louis CK.
techdragon 12y ago
I would like to suggest to anyone really interested in understanding this topic better, read about the Casmir effect http://en.m.wikipedia.org/wiki/Casimir_effect http://en.m.wikipedia.org/wiki/Casimir_effect The Casmir effect and the Casmir-Polder Force is considered by many scientists to be a result of asymmetrical forces being generated by and or from the quantum vacuum based on the materials and geometries being used. It did take decades to verify to the level people don't consider it experiment error, and we're sill arguing over if it's really a quantum mechanical effect. Some people do not like the whole quantum field theory thing and their efforts to disprove things related to it is important for science. Personally QFT makes a lot of sense to me so I look at the work being done at Eagleworks and wish there was a way to help accelerate the pace of research because this thing isn't the LHC its not trillion dollar stuff, a few million is probably the total bill to do all the work and the subsequent re verification by JPL, NASA and Johns Hopkins that they want to do. This could be "done" in a year if we stop going slowly. It's 2015 and I would like my hover car next year thanks.
tmp-20150107 12y ago
The Cannae Drive was obviously not invented by a Scotsman... ;)
FrankenPC 12y ago
What's the deal with power scaling? The OP says: 50W of power = 50uN. That's 0.05mN. 2500W of power = 750mN 2500W is 50x 50W of power. 0.05mN x 50 = 2.5mN, not 750mN. That's a hell of a ramp up in thrust. Does it keep ramping the more power you put into the cavity? If so, how much power is required to say get a fighter jet to fly which is around 100,000N of thrust? Or is my math WAYYY off?

208 points by curtis 12y ago

I'm not a physicist but as someone that's always looked at over-the-top headlines and groaned while internally wishing they were true, I just want to say: this is all so very cool and I'm so excited to see where this takes us. Even if it's not the start of a Star Trek-eseque future, this is some pretty neat stuff and I'm really anxious to hear more about what new gates of knowledge this unlocks. The plot line is right out of sci-fi and it's what makes me love technology so much: we truly never know what we will find.

aetherson 12y ago
Understand that the most likely gate of knowledge that this unlocks is, "oh, there was some kind of magnetic interaction between the test drive and the harness," or something to that effect. The proper Bayesian approach to these tests is to downgrade your prior of "drives require reaction mass" from 99.99999999% to 99.999999%
- kristjankalm 12y ago
  exactly -- I'd guess not too many non-physicits realise what's a prior for 'conservation of momentum violated'
kristjankalm 12y ago
the problem is that the excitement is generated by the use of exotic terminology. you wouldn't get excited if a single study reported that alzheimer's was reversed by copious praying and sprinkling of holy water.

binalpatel 12y ago

I know it's unlikely that the EmDrive is real, and even more unlikely that the "warp drive" effects that some have been talking about are real. But...I really hope they are. What a world it'd be if these things prove out to be real.

higherpurpose 12y ago
I think even if it proves real, it would still take around 50 years to put in flying cars and such. But perhaps a bit less for using it in satellites. Still it's not too long on the humanity scale of time.
- astrodust 12y ago
  Why would it take fifty years? This isn' the 1800s where it takes a half century for flush toilets to catch on. We're in an era where things go from laboratory to ubiquitous inside of a decade.
  - mahranch 12y ago
    This is less like flush toilets and more like computers. It took nearly 50 years for the first computers to sit in consumer's home offices. It took time for the technology to be miniaturized and cheap enough to make its way to consumer electronics. Or even cell phones. We were using radio signals in hand held devices for nearly 50 years before a vast majority of consumers were walking around with phones in their pockets in the mid to late 90s. Sure, there were early adopters in the late 80s and early 90s, but the technology was still expensive. And the technology (like walkie talkies) had existed for decades before...
    - danielweber 12y ago
      If this were proven true, there would be a completely manic gold-rush of capital into the area. Flying cars that operate at less than 1/10th the energy of cars on the road now? This would very quickly move from "let's wait for NASA to do more tests" to "let's beat NASA to the test." That's all assuming it's real, of course. I'd bet against it.
      - ZoFreX 12y ago
        Who says this will use less energy? The remarkable property of it is the (seeming) violation of conservation of momentum, not its efficiency.

Steuard 12y ago

This is not worth getting excited about. Really. Extraordinary claims require extraordinary evidence. These drives would violate conservation of momentum.[0] Conservation of momentum is built in to the known laws of physics at an extraordinarily deep level. It is obviously not impossible that our known laws are wrong, but the alternative would be to somehow produce a radically different set of physical laws that nevertheless reproduce every test of existing theory to high precision (as much as 14 digits of accuracy in some cases). And you probably also need to explain why the existing theory worked so very well if its bedrock foundation doesn't describe our universe. So really, don't get excited. And don't send these folks money that could do real good elsewhere until they give at least some small reason to expect that it's not a wild goose chase. (Edit to add: I wish this were real, too. With all my heart. But it's not a realistic wish.) [Re-edited to cut some less-appropriate phrasing.] [0] Yes, I know the EmDrive site FAQ (http://emdrive.com/faq.html http://emdrive.com/faq.html) claims that it doesn't violate conservation of momentum. The explanation of why it doesn't actually indicates that it does: "The electromagnetic wave momentum is built up in the resonating cavity, and is transferred to the end walls upon reflection." But the wave's momentum has to come from somewhere, too. So either this is just equivalent to a photon drive (propelled by shooting light out the back), or their device is pulling momentum out of nowhere.

Tossrock 12y ago
Why isn't it worth getting excited about? I get excited about lunch. It costs me nothing to follow the progress on low-probability, high impact technological advancements (see: space elevators, commercial fusion power, etc)
- Steuard 12y ago
  I guess this is really the point: space elevators and commercial fusion are many, many orders of magnitude more likely to pan out than this is. Both of those are engineering challenges, and materials science challenges. They may be insurmountable ones, or they may not. But neither one would unconditionally require changes to the bedrock principles of physics. Human beings are not good at distinguishing between levels of "very low probability". Getting excited about space elevators is awesome, even though we're awfully unlikely to see them in our lifetimes and they might never pan out. But these drive theories are pretty literally too good to be true.

tlb 12y ago

1 micronewton / watt is a surprising amount of thrust. The implied velocity of whatever it's pushing against is 1e6 m/s, which is 1/300 the speed of light.

hliyan 12y ago
How does one calculate this?
- TheLoneWolfling 12y ago
  (1 micronewton / watt)^-1 Units cancel out to give m/s. This is just specific impulse. Though Isp is generally measured in seconds (implied gravitational field of the Earth gives s * m/s/s = m/s.)
heliumcraft 12y ago
isn't that super low? if 1 micronewton = 1 newton * 10^-6 then to push against 1kg it would require 1.000 MWatts?
- tlb 12y ago
  Super-low compared to pushing against matter. But 300x higher than pushing against photons.
  - TheLoneWolfling 12y ago
    Not to mention you don't have a high-powered beam of photons cooking everything behind you.
MertsA 12y ago
What's more surprising is that every number I've seen for the higher power Chinese test was 750 milinewtons for 2.5kw of power. That's 300 micronewtons per watt of power.
- 12y ago

railgun2space 12y ago

Can such a drive be built at home? Would be a wonderful maker pet project.

ivanb 12y ago
Easily. Here is one created by a Russian guy https://youtu.be/vcaOKX7Ko7w https://youtu.be/vcaOKX7Ko7w

digitalzombie 12y ago

Sweet. Best case, we get a new awesome thrusters. Worst case, we get the learn new things. So far these drives have pass tests and stumped experts and researchers. So even if it doesn't violate the current laws of physic, it'll paint a better picture of the current laws of physic and better testing method in the future.

issa 12y ago
This is exactly my attitude. I'm shocked that people don't think twice about spending money on frivolous or even harmful things, but balk at the idea of paying for pure research.
- Retra 12y ago
  You don't want to shovel fuel into a crackpot industry. That actually prevents real science from being done.
  - Intermernet 12y ago
    Being snarky, but a lot of the world's consumer economy can be seen as shoveling fuel at crackpot industries. You're correct, but I'd rather a few million dollars going to this research than a few million dollars going to some magnetic-healing-band toting pseudo-guru. The "first world" wastes ridiculous amounts of money every second. Can we divert at least some of it to disproving crack-pot scientific ideas? It'd at least be entertaining (like Mythbusters on steroids!).
  - issa 12y ago
    This isn't an example of a "crackpot" theory. Everyone seems to agree that SOMETHING is happening. Even if the explanation is simply known-physics (which is overwhelmingly likely) there is still value in solving the mystery.

wbhart 12y ago

Comparing the Chinese results with the American results, it seems that raising the wattage by a factor of 50 raises the thrust by a factor of 15000. That's somewhat hard to believe. On the other hand, the linked pdf from the Chinese team suggests that at just 3 times the wattage of the American group, they got 1500 times the thrust. I think there is some confusion somewhere.

Tossrock 12y ago
It seems like an impossibly basic mistake, but confusing micro- and milli- newtons would make the math a lot more reasonable.
- Bud 12y ago
  Not impossibly basic at all. Space missions have failed because of these kinds of basic math errors: http://www.wired.com/2010/11/1110mars-climate-observer-report/ http://www.wired.com/2010/11/1110mars-climate-observer-repor...
  - oldmanjay 12y ago
    I almost want another failure so people will stop pulling this out as an all-purpose rhetorical showstopper.
waterlesscloud 12y ago
Well, the natural world is full of non-linear and/or discontinuous responses, so it's not crazy if there's some sort of threshold at work. But yeah, it's more likely there's some confusion in there.
- wbhart 12y ago
  It's an important question because the article claims "The applications for a device that functions as these appear to would basically replace every form of transportation and thrust invented by humans to date. Such a device would easily be used to make cars, planes, bikes, boats, etc., all more efficient, clean, and cheap." Given that the thrust required for a car would be something like 40,000N, unless the device scales far better than linearly, you'll need a 25GW power station in your car to even make it go.

narrator 12y ago

I think this technology, if real, should be shut down and controlled by the government. Officially, it should be denied and declared to be quackery. It would likely cause grave security problems. Just think of the capabilities this would give the bad guys. We already went too far with technology with the discovery of nuclear weapons and enormous effort has been invested in controlling that technology for decades. The whole reason we went into Iraq was to prevent them from getting technology (WMDs) that we think they shouldn't have access to. I don't think humanity will be ready for this kind of technology until we have elevated our civilization to a "higher level".

heliumcraft 12y ago
> to prevent them from getting technology (WMDs) WMDs = pretext, real reason: Oil and GeoPolitical
astrodust 12y ago
The irony of your misinformed statement is that the alleged WMDs were American made and sold to Iraq. The classic quote from the time "We know they have WMDs because we have the receipts!"
- lotsofmangos 12y ago
  Hey, don't forget the British. We tried to build them that super-gun thingy.
narrator 12y ago
Hmm.. I was hoping somebody would write a well reasoned response to why this point of view is wrong so I could reasonably change my mind. Well at least I got it out there, even if I had to sacrifice karma.

hooo 12y ago

I'd really like this to be real. I think they need to precisely measure the mass of the whole device before and after the experiment, to make sure the thrust isn't coming from ionization or some decay.

TheLoneWolfling 12y ago
They also need to check their vacuum. There's a whole lot of power being thrown around inside those boxes.

nsxwolf 12y ago

As far as I have seen, NASA hasn't actually said anything about this. Is the story even real?

mrfusion 12y ago

If (big IF) this turned out to be real, could we use these on helicopters instead of blades? Or are blades more efficient? Also would it make the hoverboard feasible, or does it require way too much energy?

indrax 12y ago
Blades are much more efficient. I've done some back of the napkin estimates that this would levitate if paired with lockheed's supposed small fusion reactor. (and works at all, and if the drive reaches improvements that one paper thought possible, and if it scales with power input, and ....) This inefficiency would still be great in space because you don't have to carry reaction mass with you. (and hovering on earth would mean sustained 1g acceleration in space, which is fantastic.) But if you're swimming through reaction mass anyway, then just push it as efficiently as possible.

MCRed 12y ago

I've some direct experience with a similar situation. I can speak to the issue of "why hasn't spaceX or other major company experimented with this". During the "Cold Fusion" era, when Pons & Fleishman had claimed to develop room temperature fusion, I worked for a major US lab doing superconductor research. (We invented the first superconductors that operated at liquid nitrogen temperatures-- Y1B2C3O) While fusion isn't our area of investigation we, being physicists, were curious. We managed to get our hands on a pre-print of the Pons & Fleishman study and did our own experiments. We kept this very hush hush. We didn't want it getting out that we were doing the experiments or people would claim that we replicated them. So, I believe that SpaceX and other companies are experimenting with this, and if they found good results (as the eagle works tests imply they would) they would continue to do so, but in secret.) We eventually published our paper because we constructed a novel experiment that disproved the P&F observation, from our perspective. None-the-less, true to our fears, this was later reported by "Mondo 2000" (The "arse technica" crossed with WIRED of the day) that we had "confirmed cold fusion is real!!1!1". The letter to the editor I wrote and got our most eminent physicist to sign was never printed by the magazine (IIRC). When you get to the fringes-- that's where the action is-- but it's also where you can have confusing or odd results. And even 30 years ago the media was not trustworthy enough to reveal these results to. Our paper was published in a journal, and yet the media still mis represented the results.

ableal 12y ago
Wishful thinking, if not base motives, overpowers most common sense. This seems to be about "reaction-less drives" - I remember reading about how hard-headed SF editor J.W.Campbell had a weak spot for such devices, several decades ago. He entertained a few demos, if memory serves. Didn't pan out then, probably won't now.
drzaiusapelord 12y ago
This is one of the many reasons why I consider all "fururist" media as just sci-fi wish fulfillment for kiddies. Its just incredible how unreadable /r/futurology is, for example. Its just a lot of pats on the back about some amazing life-changing technology, that is eternally 10 years away. I don't have access to the Mondo 2000 stuff today, but if any of that was to believed we'd have AI masterminded rockets to moon condos and eternal life by now. The big advances were actually missed as things like interchangable and standardized protocols, power saving SoCs, incremental battery improvements, touchscreens, and fast networks are "boring" compared to spacetravel and robots and such. I feel I'm also seeing the same hype train today with VR, which has unsolved major issues like motion sickness and questionable applications in gaming, let alone anywhere else. To a lesser extent I see the same thing with electric cars that are always somehow 2-3 years from affordability and economic and range parity with ICE cars. These 2-3 years keep blowing past us, but there's no 200 mile range $20,000 car yet, if there will ever be. Its a shame that practical and real advances are often "boring" to the typical sci-fi obsessed INTJ males who dominate science on the internet. I see so much spilled ink about SpaceX and very little about the upcoming SLS and its planned pioneering manned missions or NASA's robotic and science missions, which are all mindblowingly amazing to me. Sadly, this has all become politicized in the most asinine way possible with a dedicated libertarian group on the web voicing this private vs public rivalry to attack NASA, which is ironic as SpaceX is more or less a welfare program of NASA and the US taxpayers. I hope this fad doesn't last long and good science, real breakthroughs, and the largely unpredictable and usually unsexy, in terms of whiz bang space operas, future continues to unfold before us in a wonderful way. The SLS will have us on an asteroid with just boring old chemical rockets, while the futurists continue to sell snake oil to the low information true believers and diminish the amazing and real accomplishments of the day. "Everything's amazing and nobody's happy." - Louis CK.

techdragon 12y ago

I would like to suggest to anyone really interested in understanding this topic better, read about the Casmir effect http://en.m.wikipedia.org/wiki/Casimir_effect http://en.m.wikipedia.org/wiki/Casimir_effect The Casmir effect and the Casmir-Polder Force is considered by many scientists to be a result of asymmetrical forces being generated by and or from the quantum vacuum based on the materials and geometries being used. It did take decades to verify to the level people don't consider it experiment error, and we're sill arguing over if it's really a quantum mechanical effect. Some people do not like the whole quantum field theory thing and their efforts to disprove things related to it is important for science. Personally QFT makes a lot of sense to me so I look at the work being done at Eagleworks and wish there was a way to help accelerate the pace of research because this thing isn't the LHC its not trillion dollar stuff, a few million is probably the total bill to do all the work and the subsequent re verification by JPL, NASA and Johns Hopkins that they want to do. This could be "done" in a year if we stop going slowly. It's 2015 and I would like my hover car next year thanks.

tmp-20150107 12y ago

The Cannae Drive was obviously not invented by a Scotsman... ;)

FrankenPC 12y ago

What's the deal with power scaling? The OP says: 50W of power = 50uN. That's 0.05mN. 2500W of power = 750mN 2500W is 50x 50W of power. 0.05mN x 50 = 2.5mN, not 750mN. That's a hell of a ramp up in thrust. Does it keep ramping the more power you put into the cavity? If so, how much power is required to say get a fighter jet to fly which is around 100,000N of thrust? Or is my math WAYYY off?