Rakaydos Posted February 9, 2015 Share Posted February 9, 2015 I rather suspect the energy density being higher at one end of an open container might be it. If virtual particle pairs are more likely to spawn in the narrow enf of the cone, simple brownian motion means theres going to be more interactions with the front of the cone than with the back of the cone- this virtual pressure differental is what pushes it foreward. Link to comment Share on other sites More sharing options...
CptRichardson Posted February 9, 2015 Share Posted February 9, 2015 (edited) I rather suspect the energy density being higher at one end of an open container might be it. If virtual particle pairs are more likely to spawn in the narrow enf of the cone, simple brownian motion means theres going to be more interactions with the front of the cone than with the back of the cone- this virtual pressure differental is what pushes it foreward.Uh, no, because they got reverse thrust from reversing the current.- - - Updated - - -It might be an ion drive using the copper plate it's made of as fuel (think ablating it off like you can do with heavy lead etc on some ion drive designs ).It might be a heating/gassing thrust from mistakes in the vacuum seal in testing.It might be magnetic propulsion (can and does happen and is used in some instances).By all means the "thrust" can be real. But it may not be an EM drive as such that it pushes off the quantum foam. Saying it is, is like saying there are rivers on mars because we can see the ravines and valleys through out hand held telescope...Uh, they've gotten as perfect as they can to vacuum. If they had seal errors, it would have been pretty obvious, and given that the test results are within something like 2% of the atmospheric tests, it seems to not be an atmosphere thing. Likewise, they did check the magnetic interactions as stated in the article, and have ruled out most, if not all such events. I will grant that the copper plate ablating is possible, but I don't know.Addendum: Nope, copper ablation can be ruled out. A second article just posted shows that the copper housing doesn't even reach 100 degrees F. Edited February 9, 2015 by CptRichardson Link to comment Share on other sites More sharing options...
Rakaydos Posted February 9, 2015 Share Posted February 9, 2015 Uh, no, because they got reverse thrust from reversing the current.- - - Updated - - -Uh, they've gotten as perfect as they can to vacuum. If they had seal errors, it would have been pretty obvious, and given that the test results are within something like 2% of the atmospheric tests, it seems to not be an atmosphere thing. Likewise, they did check the magnetic interactions as stated in the article, and have ruled out most, if not all such events. I will grant that the copper plate ablating is possible, but I don't know.Reverse the current? I read it as they turned the engine around to rule out some kind of directional enviromental intrraction.What would revercing the current even do, fill it with negative microwaves? Im pretty sure the magnatron uses AC anyway, given that its described in hz. Ac reverse s the current constantly- there wouldnt be any difference. Link to comment Share on other sites More sharing options...
RainDreamer Posted February 9, 2015 Share Posted February 9, 2015 So many awesome science things, so little money. If these people got more fund, they may already figure out a more definitive proof if it works or not from more vigorous testing. Link to comment Share on other sites More sharing options...
Northstar1989 Posted February 9, 2015 Author Share Posted February 9, 2015 Because with infinite delta vee, they could fly to an asteroid and push it into a collision course with Earth. If they fly to an asteroid that turns out to be a rubble pile, they can just fly to a new one.I somehow doubt a cubesat would last long enough to do this (I imagine it would take at least a few years). But is somebody built a satellite the size of a large comsat, it could probably be done... Regards,Northstar Link to comment Share on other sites More sharing options...
magnemoe Posted February 9, 2015 Share Posted February 9, 2015 I somehow doubt a cubesat would last long enough to do this (I imagine it would take at least a few years). But is somebody built a satellite the size of a large comsat, it could probably be done... Regards,NorthstarNo, simply no, let us use Dawn as an relevant example its 1.3 ton and have 90mN trust. Let say the emdrive works better so you have 1N, an now try to move an 10^12 ton asteroid. I leave it to you to calculate how much time an 1 m/s burn will take, hope the evil organization is long lived. Also note that known asteroids who pass close to earth is watched regularly, and you need your own deep space network, and yes you need an non rotating asteroid or you have to stop the rotation first and you need to burn from an direction who give you sunlight.Even if you manage to do so lets hope nobody find out, they would do two thing 1) send an far more powerful probe or some nukes as fallback and move it out of way 2) go to war against you. Link to comment Share on other sites More sharing options...
Scotius Posted February 9, 2015 Share Posted February 9, 2015 Uh, no, because they got reverse thrust from reversing the current.- - - Updated - - -Uh, they've gotten as perfect as they can to vacuum. If they had seal errors, it would have been pretty obvious, and given that the test results are within something like 2% of the atmospheric tests, it seems to not be an atmosphere thing. Likewise, they did check the magnetic interactions as stated in the article, and have ruled out most, if not all such events. I will grant that the copper plate ablating is possible, but I don't know.Addendum: Nope, copper ablation can be ruled out. A second article just posted shows that the copper housing doesn't even reach 100 degrees F.Can you post link to the second article? My Google-fu is failing me. Link to comment Share on other sites More sharing options...
K^2 Posted February 9, 2015 Share Posted February 9, 2015 This is still several orders of magnitude more thrust than they should be measuring. There is going to be a reaction mass involved. Link to comment Share on other sites More sharing options...
Streetwind Posted February 9, 2015 Share Posted February 9, 2015 I just finished reading through the NSF thread on this, and I'm picking up the asploded pieces of my brain as we speak.That's the difference between a bunch of speculating amateurs and a bunch of speculating real scientists, I guess... So yeah, I'll pass. There is nothing whatsoever about this topic that I feel qualified to comment on anymore. Link to comment Share on other sites More sharing options...
CptRichardson Posted February 9, 2015 Share Posted February 9, 2015 Can you post link to the second article? My Google-fu is failing me.http://nextbigfuture.com/2015/02/more-emdrive-experiment-information.html#moreThe official topic on the NASA forums where they're discussing it is here:http://forum.nasaspaceflight.com/index.php?topic=36313.420Interestingly, they seem to have solved how it works without violating the conservation of momentum. The act of kicking against virtual particles transforms them into semi-virtual particles with momentum equal and opposite(ish) to their engine. The issue they're having is that their magnetic confinement isn't very good and they're losing a large percentage of their thrust as random scatter in all directions if their model is correct. Link to comment Share on other sites More sharing options...
Frozen_Heart Posted February 9, 2015 Share Posted February 9, 2015 Does anyone know if they plan to do more tests and when?This is quite intriguing... Link to comment Share on other sites More sharing options...
Northstar1989 Posted February 9, 2015 Author Share Posted February 9, 2015 http://nextbigfuture.com/2015/02/more-emdrive-experiment-information.html#moreThe official topic on the NASA forums where they're discussing it is here:http://forum.nasaspaceflight.com/index.php?topic=36313.420Interestingly, they seem to have solved how it works without violating the conservation of momentum. The act of kicking against virtual particles transforms them into semi-virtual particles with momentum equal and opposite(ish) to their engine. The issue they're having is that their magnetic confinement isn't very good and they're losing a large percentage of their thrust as random scatter in all directions if their model is correct.That's actually exactly how I thought it worked (I even argued in favor of vacuum plasma as an explanation on these forums some time ago) so I'm not surprised... Regards,Northstar Link to comment Share on other sites More sharing options...
Bill Phil Posted February 9, 2015 Share Posted February 9, 2015 http://nextbigfuture.com/2015/02/more-emdrive-experiment-information.html#moreThe official topic on the NASA forums where they're discussing it is here:http://forum.nasaspaceflight.com/index.php?topic=36313.420Interestingly, they seem to have solved how it works without violating the conservation of momentum. The act of kicking against virtual particles transforms them into semi-virtual particles with momentum equal and opposite(ish) to their engine. The issue they're having is that their magnetic confinement isn't very good and they're losing a large percentage of their thrust as random scatter in all directions if their model is correct.If they're losing a bunch of thrust from that, then that means that there might be even more potential from this engine! Link to comment Share on other sites More sharing options...
Rakaydos Posted February 9, 2015 Share Posted February 9, 2015 This is still several orders of magnitude more thrust than they should be measuring. There is going to be a reaction mass involved.Am I correct in recalling tat Vrtual particles are more likely to spawn in areasof higher energy density?My speculation is that by having an energy density gradent inside the tapered resonance chamber, virtual particles appear more often at one end, expand to equilibrium (pushing on the front more than the back) and cancel out. Link to comment Share on other sites More sharing options...
CptRichardson Posted February 9, 2015 Share Posted February 9, 2015 If they're losing a bunch of thrust from that, then that means that there might be even more potential from this engine!That is the case. This is why they believe they can get WTFBBQ grade thrust with superconducting magnets, as they'll be able to magnetically confine the thrust into a near laser beam of semi-virtual particles. Granted, they'll also have to figure out how to cool their engine at that point, as it seems it will climb up to 1000 degrees celsius at that thrust level.- - - Updated - - -Am I correct in recalling tat Vrtual particles are more likely to spawn in areasof higher energy density?My speculation is that by having an energy density gradent inside the tapered resonance chamber, virtual particles appear more often at one end, expand to equilibrium (pushing on the front more than the back) and cancel out.This is actually sort of their explanation, yes. The two dielectric disks are forcing more particles to come into existence on one end, which are then further excited by the radio transceiver inside, then their bounce out is kinda contained by the magnetic fields, forming thrust from the then semi-virtual particles, thus upholding the conservation of momentum and thermodynamics. Link to comment Share on other sites More sharing options...
Frozen_Heart Posted February 9, 2015 Share Posted February 9, 2015 Ok maybe I'm just being dumb but what are virtual particles? What properties do they have? Link to comment Share on other sites More sharing options...
Robotengineer Posted February 9, 2015 Share Posted February 9, 2015 50 thousandths of a newton? I thought ion-electric propulsion was slow. What about using some sort of similar emitter in a blow your own light sail type thing? Link to comment Share on other sites More sharing options...
CptRichardson Posted February 9, 2015 Share Posted February 9, 2015 (edited) 50 thousandths of a newton? I thought ion-electric propulsion was slow. What about using some sort of similar emitter in a blow your own light sail type thing?Uh, it's already about... twice the thrust an ion drive would get with the amount of power being put into it. At a proper kilowatt (they're only using 50 watts right now. For reference, the lightbulbs you use to look at stuff use about 10 watts more), it should be about .1 newton with the current test article. As said, that's twice the thrust of current ion thrusters. If they can tune the thing properly, even without using supercondutor magnetic confinement they believe they can hit .4 newton per kilowatt, which would be 7 times the thrust of current ion thrusters.- - - Updated - - -Ok maybe I'm just being dumb but what are virtual particles? What properties do they have?Virtual particles are the electron/positron pairs that are constantly popping into existence and annihilating in micro-seconds always, everywhere. They're a part of the 'quantum foam' that is the substrate of the universe, and a major part of hawking radiation and other fun stuff. But, as it turns out, kicking them with radio waves and magnetic fields keeps them from annihilating for long enough to be useful. Edited February 9, 2015 by CptRichardson Link to comment Share on other sites More sharing options...
NFUN Posted February 9, 2015 Share Posted February 9, 2015 50 thousandths of a newton? I thought ion-electric propulsion was slow. What about using some sort of similar emitter in a blow your own light sail type thing?You could use energy to create photons to use as propulsion, as mentioned somewhere earlier in the thread, but it is expensive and the thrust is miniscule. Link to comment Share on other sites More sharing options...
K^2 Posted February 9, 2015 Share Posted February 9, 2015 (edited) Am I correct in recalling tat Vrtual particles are more likely to spawn in areasof higher energy density?My speculation is that by having an energy density gradent inside the tapered resonance chamber, virtual particles appear more often at one end, expand to equilibrium (pushing on the front more than the back) and cancel out.Totally irrelevant. Even if EMDrive uses virtual particles for recoil, virtual particles must vanish. The total "exhaust" mass must therefore be zero. Massless "exhaust" is equivalent to photon drive, which has maximum efficiency of 1N/300MW. Efficiency higher than that guarantees presence of reaction mass. It's that simple.Ok maybe I'm just being dumb but what are virtual particles? What properties do they have?Virtual particles are ones that propagate off the shelf. They violate E² = p²c² + (mc²)², which is true for "real" particles. Virtual particles show up in various interactions, as exchange particles, for example. Virtual photons carry electromagnetic forces, etc.Finally, because virtual particles "temporarily" violate conservation laws, they must promptly vanish. That's a hand-wavey explanation of it, but it should do for purposes of discussion at hand. Edited February 9, 2015 by K^2 Link to comment Share on other sites More sharing options...
Sean Mirrsen Posted February 9, 2015 Share Posted February 9, 2015 Ok maybe I'm just being dumb but what are virtual particles? What properties do they have?Most of this science is way above my head in terms of complexity, but the principle itself is ridiculously simple. It's... for lack of a more succinct description, it's the aether theory multiplied by quantum physics. Space is not actually empty at all, you just need very specific circumstances to be able to push off of the stuff that space is filled with. Link to comment Share on other sites More sharing options...
-Velocity- Posted February 9, 2015 Share Posted February 9, 2015 Just don't get your hopes up, EM Drive fans. This is almost certainly not going to work out. Just because NASA is testing something doesn't mean it's reputable. I've actually worked in government. It was depressing. A lot of people just trying to justify their jobs, basically. So NASA isn't exactly the beacon of science it used to be. There are people there who can't be fired, basically, and can do some whacky stuff.So the EM drive is supposedly making thrust in a vacuum. Ok, if that's actually true, now, move the metal walls of the vacuum chamber away. I'm wondering if it's possible it's inducing eddy currents in the walls of the chamber that are providing a "thrust". Link to comment Share on other sites More sharing options...
CptRichardson Posted February 9, 2015 Share Posted February 9, 2015 Totally irrelevant. Even if EMDrive uses virtual particles for recoil, virtual particles must vanish. The total "exhaust" mass must therefore be zero. Massless "exhaust" is equivalent to photon drive, which has maximum efficiency of 1N/300MW. Efficiency higher than that guarantees presence of reaction mass. It's that simple.Virtual particles are ones that propagate off the shelf. They violate E² = p²c² + (mc²)², which is true for "real" particles. Virtual particles show up in various interactions, as exchange particles, for example. Virtual photons carry electromagnetic forces, etc.Finally, because virtual particles "temporarily" violate conservation laws, they must promptly vanish. That's a hand-wavey explanation of it, but it should do for purposes of discussion at hand.Except they're saying that's NOT the case. They're trying to figure out how to check for it, but they believe the push modifies the virtual particles so that they do not immediately annihilate, but instead convey the thrust reaction out. They're trying to figure out how to check for a particle wake right now as part of their continuing study.- - - Updated - - -Just don't get your hopes up, EM Drive fans. This is almost certainly not going to work out. Just because NASA is testing something doesn't mean it's reputable. I've actually worked in government. It was depressing. A lot of people just trying to justify their jobs, basically. So NASA isn't exactly the beacon of science it used to be. There are people there who can't be fired, basically, and can do some whacky stuff.So the EM drive is supposedly making thrust in a vacuum. Ok, if that's actually true, now, move the metal walls of the vacuum chamber away. I'm wondering if it's possible it's inducing eddy currents in the walls of the chamber that are providing a "thrust".Already ruled out from what I understand. Link to comment Share on other sites More sharing options...
Frozen_Heart Posted February 9, 2015 Share Posted February 9, 2015 As I've pointed out I'm sceptical this is real...But there is some people here that still won't believe it works even if we have satellites being propelled by them.Just wait for further test results. Don't denounce it out of hand. Link to comment Share on other sites More sharing options...
N_las Posted February 9, 2015 Share Posted February 9, 2015 As I've pointed out I'm sceptical this is real...But there is some people here that still won't believe it works even if we have satellites being propelled by them.Just wait for further test results. Don't denounce it out of hand.It is just like the faster-than-light neutrinos from a few years back. Most people who knew something about the topic expected it to be a simple error, and of course it was a simple error. This will turn out exactly as that. Link to comment Share on other sites More sharing options...
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