That NASA EM Drive Paper: An Expert Opinion

A week or two ago we featured a research paper from NASA scientists that reported a tiny but measurable thrust from an electromagnetic drive mounted on a torsion balance in a vacuum chamber. This was interesting news because electromagnetic drives do not eject mass in the way that a traditional rocket engine does, so any thrust they may produce would violate Newton’s Third Law. Either the Laws Of Physics are not as inviolate as we have been led to believe, or some other factor has evaded the attempts of the team to exclude or explain everything that might otherwise produce a force.

As you might imagine, opinion has entrenched itself on both sides of this issue. Those who believe that EM drives have allowed us to stumble upon some hitherto undiscovered branch of physics seized upon the fact that the NASA paper was peer-reviewed to support their case, while those who believe the mechanism through which the force is generated will eventually be explained by conventional means stuck to their guns. The rest of us who sit on the fence await further developments from either side with interest.

Over at they have an interview from the University of Connecticut with [Brice Cassenti], a propulsion expert, which brings his specialist knowledge to the issue. He believes that eventually the results will be explained by conventional means, but explains why the paper made it through peer review and addresses some of the speculation about the device being tested in space. If you are firmly in one of the opposing camps the interview may not persuade you to change your mind, but it nevertheless makes for an interesting read.

If EM drives are of interest, you might find our overview from last year to be an illuminating read. Meanwhile our coverage of the NASA paper should give you some background to this story, and we’ve even had one entered in the Hackaday Prize.

167 thoughts on “That NASA EM Drive Paper: An Expert Opinion

  1. Unless and until nuclear fusion or antimatter reactors become practical, the power requirements for even a satellite sized craft are simply too large for any current power source. The efficiency will also have to be improved by many orders of magnitude from the current mN/kW otherwise it would make more sense to mine methane from moons, comets, and planetary rings.

    /Pedantry alert

    Assuming the EM drive utilizes some undiscovered phenomena, it would not violate any of Newtons laws. Especially the 3rd law. Just because the claimed action of the drive does not eject any matter does not mean it does not generate a force.
    Its claimed action still has an equal and opposite reaction.

    1. Thank you for that ending, It’s all I have been thinking. We may not be ejecting matter from it, however some form of energy is being used to propell it.

      Another thing I have a issue with is the “Fuel-less” claim. It might not use a conventional propellant, however it still ultimately uses some kind of chemical fuel somewhere, be it the fuel burnt and stored in its batteries to the solar panels collecting energy from the fusion in the sun (or a future fusion reactor)

      1. Conservation of energy is one law, conservation of momentum is another. Some claims say this device can break conservation of energy (eg constant force leads to kinetic energy rising with v^2), but all claims say this device breaks conservation of momentum. Both laws are mathematically proven. Noether’s theorem is extremely well accepted.

        1. What’s rarely mentioned with these EM drive articles is that if the drive undergoes movement/acceleration, then energy is consumed from the waveguide cavity and needs to be replaced. That makes it highly attractive for stationary thrusters (eg hovercars).

          Conservation of energy is working fine and not in question, it’s really only the apparent lack of conservation of momentum that causes issues.

          1. To keep CoE intact you would need the universe to have an absolute frame of reference (for example in the frame of the thruster, energy is being destroyed in your scenario). If you accept that the universe is expanding that means acceleration should require vastly more energy in the direction of expansion, than, say, parallel to it and accelerating in the other direction should generate huge energy (or again CoE fails because a return trip destroys energy). Given this is missing from the data CoE cannot be working fine if the EM drive results are valid.

            This is typical with physics. You can’t pick and choose which bits you want, it’s a perfect jigsaw. Taking pieces out leaves holes only those pieces can fill. If you want to replace physics, you have to replace the whole thing.

          2. Mach’s principle, or “the distant stars determine the local laws of physics” doesn’t help the case.

            Imagine that the EM-drive thruster was the only thing that exists in the universe. There’s no other object, so the energy you put into it dissapears into… nothing? After all, momentum is relative, not asbolute. Therefore the device would destroy energy.

            If you add another object to the scene to have some point of reference for your momentum, the EM-drive would appear to be pushing the other object away no matter how far away it was. The other object is your “distant stars” which would have to feel the fact that you turn your engine on – instantly – for you to push against them.

            That would mean an influence that travels faster than light.

        2. I’m curious as to what happens to CoM if a mass that has momentum is converted into energy such that the energy is radiated out in symmetrically. Say a moving back hole evaporates (in the LHC, perhaps), or a proton and an anti proton on near parallel paths attract and eliminate. Can one say that since energy is released the ‘momentum’ of the system is preserved? What if the black hole was attracting a massive body, and its release of radiation was perpendicular to that body (so that the body was not affected by it), would the body not have gained momentum without ultimately incurring an opposite loss of momentum?

          The core of what I’m getting at is this: is it not possible that since momentum is kinetic energy of a mass, and both have pure energy equivalents (one is energy, the other is equal to energy by Einstein’s equation), that the conservation of momentum is a narrow extrapolation of conservation of energy in a world of largely stable massive objects?

          1. “I’m curious as to what happens to CoM if a mass that has momentum is converted into energy such that the energy is radiated out in symmetrically.”

            That doesn’t happen. In special relativity, conservation of momentum and conservation of energy are the same thing – it’s just conservation of 4-momentum.

            “or a proton and an anti proton on near parallel paths attract and eliminate.”

            The emitted photons have the equivalent forward momentum of the proton/antiproton pair. In the center-of-mass frame of the proton/antiproton pair, the photons gets radiated symmetrically. However, if you boost the frame (which is your example) the photons are now forward beamed.

    2. Newton’s third law says that a change in momentum must be accompanied by an opposite change in momentum. Newton’s laws are also axioms, not proofs. The proof for conservation of momentum comes from Noether’s theorem. That requires that the total momentum of a closed system must be constant, and that prohibits movement if something does not also move in the opposite direction.

      1. That is funny. People propose using lasers based on earth to provide thrust to things in space. The last time that I checked, the photon was massless. Since momentum is mass times velocity, and photons have a mass of zero, that means that photons could not possibly transfer momentum.

        1. Under Newtonian mechanics a massless object can’t carry momentum. But our Universe appears consistent with Einsteins theory of Relativity where a massless photon does carry momentum. Momentum = gamma*M0*V, gamma approaching infinity as V approached C. Or in terms friendlier to a massless photon, avoiding the infinities, momentum = E*V/C^2. Relativity simplifies to Newtonian mechanics at slow speeds, but a photon is hardly slow.

    3. Yep even it it works, it’s a matter of power and we are not anywhere smart enough to build a fusion or anti-matter reactor. Nuclear is maybe a possibility however people are terrified of it and the notion of stuffing a nuclear reactor into satellite or manned space craft is a political hot potato. I remember the freakout over Cassini.

      Right now we just need more testing to see if there is anything there or if it is just a nothing burger.

      1. Don’t judge things like this by the power requirements in the current form. If there is new physics here, we will eventually understand it and likely find that it can be made much more efficient. Look at internal combustion engines from the 19th century vs today’s engines for an example.

    4. “Unless and until nuclear fusion or antimatter reactors become practical, the power requirements for even a satellite sized craft are simply too large for any current power source. ”
      Also while not yet built beamed microwave and laser are also possible.

      1. While it’s true the temperature of the few atoms in space is near 0 Kelvin, space is as close to a perfect vacuum as you can get. We use vacuums on earth as insulation for vessels that contain both hot and cold substances. In space, spacecraft have to dump excess heat by radiating it away as infrared light. This is cooling via thermal radiation. Here on earth we use conductive cooling, were heat is transferred from one substance to another (the coolant) by direct contact. Then the coolant it spread very thin so that it’s thermal radiation can be dumped into the air very quickly, and also as thermal radiation.

        The overall temperature of space has no real effect on cooling objects other than the fact that it itself does not contribute any more heat into the object. So in reality, putting a fusion reactor in space means that’s its now a whole lot harder to keep it cool. If space was a gas or fluid at close to zero, then yeah your assumption would be valid. But there are too few atoms in space for its temperature to play a role in any cooling system.

        1. Interesting, I understand. Conductive cooling not available because of the lack of other material in space – had not thought of that. You would think because it’s cold in itself that it would be enough – but it makes sense. I have noticed the number of posts on here quoting laws of physics and the like. Unless I’m wrong – doesn’t the book on physics get thrown out the window at the quantum level? For example – the speed of light is no longer the threshold at the quantum level. I do find it interesting though, and I’m guessing that a number of different types of tests would need to be constructed to prove the theory anyways.

          1. The book on physics doesn’t become invalid at the Quantum level, you just refer to a different section of the book. The best way to think of physics is as a rule book that has two sets of rules, and depending on the size of the things you’re trying to describe via science, you pick one set of rules over the other. The first set of rules governs all the big things in the universe, me and you, planets, stars, and galaxies and is called the theory of General Relativity. The second set governs everything really small, like atoms or anything smaller, and is called the theory of Quantum Mechanics.

            Currently we are forced to look at them as separate rules/theories becuase we have yet to discover the true transition point were one ends and the other begins. However it is almost universally accepted that both theories are actually one single set of rules for describing everything in the universe, and that we are very close to unifying both theories. It’s understandable to think of the two as separate things, and that they are somehow incompatible, because without the unifying piece of information we need to see them as one single theory they kind of are incompatible. Most researchers believe that the missing bit lies with gravity, as it’s the last of the four fundamental forces that we have yet to fully explain.

            As far as the speed of light goes, it’s still the max speed at the Quantum level too. Quantum teleportation allows you to circumvent certain aspects of the speed of light, but not in any useful sort of way. For instance you can’t send matter this way, nor can you send useful information from one pit to another.

        2. ” Here on earth we use conductive cooling, were heat is transferred from one substance to another (the coolant) by direct contact.”

          Nitpicking: the advantage on Earth is that *convective* cooling is available, not that conduction is available. Conductive cooling is used in spacecraft systems all the time, and there’s nothing that would prevent you from using a heat transfer fluid in a spacecraft either (… which they do). If CPUs had to work only via radiative cooling in space, they’d all blow up.

          The difference is that on Earth, when you want to cool the coolant, you can dump it into something with a lot of fins/surface area for *air* to convect the heat away. But in space, you can’t do that – you have to radiate the heat away. And while radiative cooling is actually pretty efficient, the problem is you can’t “fake” a large surface area like you do for heatsinks and convective cooling – fins would radiate into each other, so there’d be no extra heat loss from them. You really need outer surface area.

    5. These statements are true. However, continued study of this effect is very important. Also, if we could find a way to power it, it’ll be very useful. The “fuel-less” claims get under my skin a bit. I prefer just to think about the amount of power the reaction takes and ignore the fuel source other than to think about how much the stored power would be in terms of mass/weight.

  2. > an interview from the University of Connecticut with [Brice Cassenti], a propulsion expert

    Who cares what a mechanical engineer thinks of a paper which potentially stumbles upon some new physics.

    That’s like getting “an expert opinion” on chemotherapy from a Crufts judge.

    Experienced and skills as they may be it’s not relevant.

        1. I agree, as far as has been published and discussed on the matter, it just looks like the true parts are not new (i.e. a laser or a directional yagi antenna already is a photon rocket) and the new parts are far from confirmed true (rather it seems like interaction with the lab, multiple reflections between DUT and lab allow photonic “rocket” propulsion forces over the classical photon rocket which is assumed to be in free space, like the “ground effect” of a rocket where the exhaust gas can build up pressure between ground/silo and rocket, whereas in free space this would not be the case)…

  3. “The rest of us who sit on the fence await further developments from either side with interest.”

    Here’s the thing. There’s no fence-sitting if you have any understanding of what the EM-drive is actually about: it’s a device based on pseudoscientific theories backed by experimentally and theoretically discredited versions of quantum physics, and the rest is just someone spewing jargon – it’s right in the ballpark of Jean-Louis Naudin, Andrea Rossi, or Steorn.

    The fact that a party like NASA is studying it is nothing new. They’re known to sometimes dip into the “free energy” sector as well either to study some alleged phenomenon or simply to debunk it in their spare time. They put some junior engineer or new recruit on the task as a learning opportunity, because of one simple principle: “a fool who persists in his folly becomes wise”.

    When you study these pseudoscientific claims, you either become so entrenched in them that you become a kook yourself, at which point you get a footprint on your ass, or you become that much wiser and able to recognize the error that lead to the “discovery” in the first place. For NASA it’s a win-win – weeds out the crazy people and makes the sane ones more so.

    Unfortunately the public isn’t as wise.

    1. And yet, despite the kooky and pseudoscientific theories, we actually have several working devices that produce thrust, despite all efforts to eliminate sources of error.

      The explanations might be wild but it really does appear we have a genuine phenomenon.

      1. Genuine measurement error, you mean. The thrust isn’t consistent between forward/reverse thrust (so it’s interacting with something), it’s not consistent with being proportional to power (the peak is actually at the middle power value), and the scatter from run to run vastly exceeds what they believe the measurement error is.

        There’s no evidence for a genuine phenomenon, just evidence for poor measurements.

          1. Well, I’ve got a guess. They ran twisted pair for power everywhere, but grounded everything to prevent electrostatic buildup. That defeats the purpose of the twisted pair, so the “no magnetic interaction is likely” claim in the paper isn’t true.

        1. they made a zero thrust control at eagleworks, simple stuff like your twisted pair example would show in such a test.

          also i find it disingenuous towards the scientific method to refuse to believe the results, i can understand not believing the explanation but it would be very far from the first time that we have had bad explanations for new phenomena before we figured them out, but if everyone dismisses it out of hand, refuses to do replication studies and simply denies what happens we will never get anywhere,

          it might very well be bogus but before you make an experiment that shows this we have to take the results as made in good faith, that doesn’t prevent measurement error or experimental issues from being critiqued but it does prevent the flat out refusal to contemplate the issue.

          1. In other cases you have a phenomenon first and then the bad explaination to why it happens.
            Here we have the bad explaination first, and then people who claim to have measured the phenomenon.

            See the difference? The problem here is that people don’t know where the whole EM-drive malarkey comes from, so they think that someone actually stumbled across the “effect” – that’s not at all what’s going on. It’s bogus from the start.

            In fact it started out as a grant money scam in the UK in 2000 when a guy Roger Shawyer made up the bullshit theory and set up a company Satellite Propulsion Research Ltd. to goad the UK Department of Trade and Industry to pay them a grant for a feasibility study. Shawyer completed the prototype in 2002 and claimed it produced thrust, and then a second prototype in 2006 which he claimed produced more thrust which is when the press picked it up. Shawyer started claiming he can fly the thruster in space by 2009.

            From there it got completely out of hand with Shawyer being invited to the Pentagon and Boeing looking to license the technology, and soon enough Shawyer claimed that he had delivered a demonstration drive to Boeing that produced 18 grams (!) of thrust in 2010. Boeing on the other hand said they were in no communications with Shawyer. They saw the man was a total fraud and cut off communications – which was the start for the conspiracy theories that Boeing and Pentagon knew the drive works and hushed it up.

            So here we are now, with people still trying to make heads or tails whether Roger Shawyer did or didn’t measure any thrust back in 2002, arguing about a phenomenon which was never actually shown to exist in the first place.

          2. it has gone that way a couple of times too, still isnt a good enough reason to outright dismiss the eagleworks team, dont get me wrong i have no love lost on shawyer, his theories or his original prototype, the second test directly showed that his proposed method of operation wasnt true, the thrust plate hypothesis.
            in that test thrust was also produced.

            what i am saying is this, we cant dismiss the results of experiments as our whim, if there are errors peer review and replication will find it, trying to reject the entire concept out of hand is as unscientific as shawyers guesswork.

          3. “trying to reject the entire concept out of hand is as unscientific as shawyers guesswork.”

            There’s nothing to reject. This is a Russel’s Teapot kind of situation – the actual concept was already tried and rejected, the source of it shown to be a fraud, and now people are arguing over nothing.

            It’s kinda like arguing about God – nobody knows what they’re talking about because nobody knows what God is supposed to be, but since the word “God” exists we think it refers to something and therefore there might or might not be this “God”.

            Likewise, we have this EM-drive which is no longer anything more than the copper cone in a torsion pendulum – get what I mean? There’s no theory, no phenomenon, nothing to talk about – just the device itself and the people who want to believe without knowing what they believe in.

          4. Dax, I’d like to see evidence for those assertions above, otherwise they sound like an ex post facto pontification from some tenured twonk who still doesn’t get that argument from authority is a fallacy.

          5. “argument from authority”

            I’m not making an argument from authority. Unsubstantiated claims can be dismissed with just as much evidence as was given for them in the first place: nothing.

            The problem is that since the original hypothesis was already rejected, and no new (plausible) hypotheses have been put forward, testing the copper cone as proof of concept for an EM-drive is like praying to God in order to prove that it exists. Even if your prayers are answered, you’re no wiser about God or the EM-drive. It’s just cargo cult science.

          6. Oh, so we’re going to go with the practice of skepticism as an “ism”… It’s untrue because it’s an obvious fraud, why is it a fraud? It’s a fraud because it’s obviously untrue.

            I am asking what evidence you have that it was fraud at the outset, beyond “because (authority) said it must be.”

          7. “I am asking what evidence you have that it was fraud at the outset,”

            The original author of the EM-drive was proven a fraud when he went on to lie about having produced a test article for Boeing which they never recieved, which he claims to have produced 18 grams of thrust (0.18N) which is obviously bunk considering all anyone else replicating the same experiments has managed was in the micronewtons.

          8. “they made a zero thrust control at eagleworks, simple stuff like your twisted pair example would show in such a test.”

            Nope. The zero thrust test was actually a “parallel axis” test – so the device under test was just turned 90 degrees, and the test repeated. If it’s something like a loop current, then turning it 90 degrees could also kill that interaction. Again, it’s interacting with the apparatus somehow, so it’s not surprising that turning it changes things.

            The article’s explanation against magnetic interaction is completely wrong, which you can tell if you just *look at the pictures*. They claim that “[t]he test article is tested in forward, reverse, and null thrust orientations, but dc
            power cable routing and orientation is the same for all three configurations.” Look at the pictures for the null thrust and forward/reverse thrust, and you can see that’s wrong… because you can *see the power cables turned*.

            “also i find it disingenuous towards the scientific method to refuse to believe the results,”

            I’m not refusing to believe the results. I’m saying the results that they have don’t match the conclusions they’re making.

            The fact that the reverse thrust and the forward thrust don’t match is an absolute dead giveaway that the device is interacting with the apparatus. If they had done the reverse thrust test and the thrust *hadn’t* reversed… they would’ve known that what they were measuring wasn’t real, right? Instead, the thrust reversed, so they said “aha! It’s real!”

            Except it didn’t reverse completely. The reverse thrust was much weaker – like, 12 standard deviations smaller in the ‘middle power’ case. It’s ridiculously obvious – only 1/9 of the runs showed higher thrust (at equivalent power) in reverse thrust than *any* of the forward thrust examples. So the obvious conclusion is that a sizable portion of the thrust observed (at least ~1/3) is not real.

            Add to that the problem that they have absolutely no evidence the thrust is proportional to input power (the 60 and 80 watt tests give completely consistent thrust results) and you start to realize that really, there’s no evidence here.

          9. I woulds say that production of such documents allowed in the public domain as

            Demonstrates a relationship with Boeing, and that statements such as “Boeing is not working with Shawyer” should be taken as precisely as intended, that is present tense at time of statement.

            Issues such as “our measurements differ from his measurements” does not adequately demonstrate the intent of fraud, when the effect is poorly characterised. Yes you can call VW a fraud for fudging emissions, because that is well characterised. If VW came out with a car that did “1 mile per 2 bananas” according to them, and Consumer reports tested it as needing 5 bananas to the mile, they are not a fraud then per se, because the novel claim is that it runs off bananas at all.

            Please discriminate in your use of terms such as scam and fraud, to only use them in cases where criminal intent to deceive at the outset can be proven beyond reasonable doubt.

          10. >”Please discriminate in your use of terms such as scam and fraud, to only use them in cases where criminal intent to deceive at the outset can be proven beyond reasonable doubt.”

            Why? A fraud like talking yourself a research grant to “test” a bullshit theory is a civil matter, not a criminal matter. It’s up to the defrauded to sue the scammer and if they don’t then nothing happens. Claiming you’ve delivered a non-existing thruster to Boeing isn’t a crime either – it’s just a lie – and presenting such lies makes you a fraud.

            That’s why overunity scams like Steorn are able to operate – they get people to invest essentially by charity. You make some vague claims and pull off publicity stunts and tell all the porkies you want about your grand invention, but you don’t actually sell anything or promise any return of interest; as long as you make no direct promises you are not committing a crime by taking people’s money. It’s caveat emptor.

          11. It would be disingenuous had we not confirmed to a very high level of confidence our modern theory of electrodynamics that says that this local conservation violation should not happen.

            Its not about belief; there simply is not enough quality of evidence to raise the posterior probability beyond a very small level given the very poor prior probability that a result violating momentum conservation could have been obtained.

            The fact that the replication studies that have been made have featured very different results for the amount of useable thrust that can be obtained also casts the reliability of the experiments into question.

    2. My “Sitting on the fence” comment puts me like Fox Mulder in the “I want to believe” camp.

      Of course I want to see working EM drives, who wouldn’t!

      But before I get off that fence I guess I share with most Hackaday readers that I’d like to see proof, either a practical EM drive, or an explanation of the mechanism in an impractical one. And yes, if that mechanism turns out to be explainable by conventional means and there is no EM drive, that will be fascinating too.

      Meanwhile sitting on the fence and reading the arguments for and against is both educative and entertaining. I like that, and I suspect so do many readers.

      1. And who wouldn’t want to see working overunity generators?

        It’s the same sort of junk. See the history explaination above: the whole EM-drive started out as a research grant scam by a guy who made up a bunch of pseudoscience to get funded for a feasibility study.

        There is no EM-drive. There’s no phenomenon. There’s just a copper pot and some crackpots and charlatans claiming to measure thrust out of it.

        1. Maybe, maybe not. I’ve always wondered about Microwave cutoff frequencies in a waveguide. If there is some possibility of a weird asymmetrical thrust effect, thats where I’d look….

          The em drive as it stands is close to that, so it could be plausible, or at least the documentation debunking it, should develop better models to show what is going on….

          Win – Win


            Tell me you believe this man is not a fraud.

            >”The UK MoD agreed to an export licence, and we designed, built and tested a Flight Thruster for use on a test satellite. The thruster gave 18 grams of thrust,” said Shawyer.

            This man is telling you, that he has a thruster that is capable of 180 milliNewtons of thrust which is already on-par with top of the line ion thrusters, while the rest of the world including NASA are still unable to show any evidence that the device works at all.

          2. Plus, there’s the previous NASA experiment where they directly disproved Shawyer’s ideas of why the device works, so how can the guy have a working thruster built on a theory that is shown not to work?

            Simple: he’s a fraud.

          3. Elon Musk has been accused of overpromising and underdelivering multiple times with the Tesla cars range.

            Thus, by applying the exact same principle we can assert that Tesla vehicles do not work at all, and all videos use a truck towing them with a rope that’s photoshopped out….

            Again you’re stretching for that skepticism “as an ism” circle of self confirmation, they’re crackpots because they measured thrust, and they only measured thrust because they are crackpots.

          4. @RW

            If Elon licensed a car that would get 100 mi on a charge but every licensed manufacturer couldn’t get his design to leave the garage, yes, Absolutely he would be a fraud.
            The claim is not just that ‘I’ve discovered a new phenomena’ but also ‘The phenomena is this big *stretches arms*’. If this were a fishing trip he’d be claiming Moby Dick on the end of this line for a sardine.

          5. There, you’ve gone black and white again, either it goes 100 miles or it stays in the garage. Crawls a few blocks and sputters out, hand wave away, didn’t happen, nothing to see here, same as never leaving the garage.

            Small net thrust after errors accounted for is not nothing. Maybe if you really, really flap those hands you can negate it, though to be fair, we should pull a 10^-6 Torr vacuum on you first.

          6. @ RW

            >>Small net thrust after errors accounted for is not nothing.

            That’s the thing, I and many others aren’t convinced that the errors have been accounted for. Keep in mind that JPL is measuring near the noise floor for most of their sensors. Other groups were just above this and got statistically insignificant results.
            Furthermore there’s concern that there are interactions between the test rig and the EM fields generated in the wiring or feed horn themselves; that is fields aside from the claimed interaction, fields explained through current physics. Then there’s concern that this may be a reaction to the Earth’s own magnetic field.

            The fact that everyone who has tried to replicate Shawyer’s design has gotten orders of magnitude smaller thrust suggest this guy is either selling snake oil, or takes terrible notes. 214mN/kW on his demonstrator ‘thruster’ compared to the most successful independent test thus far; 1.2 mN/kW.
            This isn’t a car backfiring down the country lane or idling a bit rough at red lights, this is a car struggling to turn over while you’re spraying ether down the intake.
            If this were a car you could sue the dealership under US Lemon Laws. Best case scenario, He’s sold you a sports car with a lawnmower engine in it.

          7. Well call me a gullible fool, but I’d believe that JPL have pretty much one of the largest bodies of experience in the world with measuring electric, magnetohydrodynamic and electromagnetic thruster designs and therefore may have a clue as to the usual sources of error.

            If you’re claiming an unusual source of error, then it’s doing something unusual.

          8. @RW
            Yes, NASA should know better.
            JPL and NASA have made mistakes before. Ignoring o-ring temperature ratings, not using the same unit system in communications between cooperating divisions, claiming to have found arsenic based life.
            They have a great track record of doing the improbable but the fact that no one has gotten close to the claims of the inventor don’t bode well for this being a real phenomena. Peer review is a necessary but not sufficient requirement to be taken seriously. More than a few bunk papers have made it through the process.

            >>If you’re claiming an unusual source of error, then it’s doing something unusual.
            No, I and most other people claiming a perfectly normal sources of error.
            Every day magnetic interactions, heat effects (yes, even in a vacuum), hell it could be something completely unrelated to the experiment. We’re talking absurdly sensitive instruments it doesn’t take much to introduce error. Ever other respectable institute has failed to generate statistically significant thrust.
            To date, the claims by the inventor are unsubstantiated and explained in his own words with quackery.
            If the JPL results are anything other than experimental error, the methodology outlined by JPL should provide reproducible results at similarly equipped institutions.

          9. JPL and NASA are not a hivemind. These are individual researchers within the organization put to the task, and if they mess it up and produce bad science it’s going in their review later – the whole organization is not going to be concentrating on this one thing; they have much more important things to do for the money and that is also the reason why they’re not necessarily testing it properly – they’re not putting all their resources into it.

            After all, if the device works as Shawyer claimed it does then there should be a clear unambiguous signal – the claimed phenomenon is supposed to be a hundred or a thousand times more powerful so that’s what they’re testing.

            The fact that they get “results” down in the noise margins of their meters is just saying that Shawyer lied and there’s nothing going on.

        2. “And who wouldn’t want to see working overunity generators?”

          If you think about it for a moment, nobody should. If local overunity was possible it would also be possible to set up a feedback loop that would grow to swallow the entire Universe. In fact that this hasn’t occurred somewhere, (given the size and age of the Universe) is a good indication that such a effect is utterly impossible.

          1. ” In fact that this hasn’t occurred somewhere, (given the size and age of the Universe) is a good indication that such a effect is utterly impossible.”

            Apart from we create isotopes and particles in the lab not believed to naturally occur.

            Also, I believe we could have an energy leak the size of several galaxies and not notice.

          2. Clearly you do not understand the point I was making, the nature of the conservation laws, or the implications of violating them. Furthermore your examples are nonsense, as they show no grasp of what is meant by the term ‘naturally occurring’ when referring to these things. It is very simple: if one has a complete grasp of the underlying physics it is very clear that overunity is simply not possible. It’s not that one little corner of the field would be cracked – the entire edifice would fall; things are that tightly interrelated and nothing else would work the way it clearly does now. Not just in theory, but in actual fact – the whole Cosmos would look very different on many different levels. The fact that the current model works as well as it does is the problem for those that contend that something might turn up that would allow overunity to occur – they just don’t realize it.

          3. Laws, violation, pshaw, they are statistical principles, on average, without self organisation, or due to that statistical principle tending towards self disorganisation, it doesn’t happen. Doesn’t mean it can’t, especially when you define the scope as local.

            Even when trying to fully describe local we’re invoking blank u turn universes to give somewhere for the math to go before it does another 90 degree rotation or two to flip back into our 3 spatial dimensions.

            So anyway, local overunity, why should it be spontaneous? If the forcing factors on the general randomness that get misnamed “laws” and get peoples brain bent wrong, stop it from happening by random chance.

            Generally these forcing factors are quite strong, otherwise you’d know someone whose hand had been blown off by their pencil randomly exploding, which is theoretically possible, but very highly unlikely. But from that you conclude it’s a law that pencils don’t explode. There’s now a few dozen people sitting here thinking, “But I could make a pencil explode if….” …. because there’s no law that stops pencils exploding if external organisation is brought to bear…. but if your thinking is stuck in absolutes, once having seen a pencil explode, you would claim no pencil can exist, because they all explode.

            If you can explode one pencil, without all the pencils exploding, you can explode 1 atom bomb without the entire atmosphere exploding (As was once thought likely by some physicists) and you can suck off some energy from a non-local source without the universe having to immediately collapse. Not that 99% of claims of this aren’t likely spurious. Find the way they don’t work, sure, but call them out for being impossible in concept, bad science. Save yourself the time and effort from even thinking about the crackpots, if you like, by saying “It’s statistically unlikely that your device works” and you’re right, it is. If you just want to blanket it with “That’s categorically impossible in concept”, then time will prove you wrong. However, in the religious zeal to burn the heretics, we’ve probably lost/ignored a few ideas that turn ambient heat or sound into usable energy, because it smelled like heresy and was not investigated.

          4. Rubbish. I know you think you are being open-minded but a response like this only demonstrates profound ignorance and in fact is the modern equivalent of those in the Church that dismiss the findings of science because it violates the Biblical narrative. Chasing nonsense because you want to believe it is true has never worked in this domain, and many, many have tried. The conservation laws are particularly robust and history is littered with failed assertions that they are only an epistemically impossibility. You do science no favor by these sorts of arguments, and as I have written elsewhere in this thread, probably inhibit serious study in these areas.

          5. “Rubbish. I know you think you are being open-minded but a response like this only demonstrates profound ignorance and in fact is the modern equivalent of those in the Church that dismiss the findings of science because it violates the Biblical narrative.”

            I’m not the one defending a dogma.

          6. Yes you are. You’re defending the dogma that anything is possible regardless. Your position is tantamount to the assertion that Biblical cosmology should be given consideration because the version science offers is subject to revision and therefore not absolute. The notion that this drive (or overunity) may be possible is rooted in too narrow a grasp of the concepts of what the conservation laws represent on your part – not a overly rigid view on ours.

          7. Not anything.

            Every time we make better tools, more accurate, more revealing, we discover we were only almost right before. Sometimes, only approximately right, and very occasionally, completely misled. It is inevitable. 50 years from now, current state of the art as taught to undergraduates is going to look as dated and quaint as the plum pudding model of the atom does now.

          8. Do you ever wonder why it is always those that clearly do not have a complete and clear idea of the conservation laws are the ones extending the argument that they may be overturned one day? You only think this might happen because you just don’t understand what you are asserting. That is why these discussions always end with either this hollow appeal to the idea that because some widely held ideas in science have been found wrong, that this one will be too, or the more ludicrous accusation of a conspiracy to maintain the status quo – none of you ever can extend any real arguments based on solid mathematics and established principles. There have been anomalous observations? So what? Everyone that claims to have seen a ghost made an observation of what they believed was an anomaly – that isn’t an argument for non-corporeal entities.

            The fact remains that one after another claims of devices that violate the fundamental structure of the universe have always failed to live up to the promises those that create them and the hopes of those that support them and this will continue to be the case. Not that it will stop the next round of these farces as they progress through the same dreary pattern of wild claims, dismissal by experts, faith-based support, and inevitable disappointment.

          9. “The fact remains that one after another claims of devices that violate the fundamental structure of the universe”

            Now you’re going too far. “Violate all of the physics we’ve observed” is better. Fundamentally, on a global scale, we don’t treat the Universe as conserving energy. Cosmologists don’t conserve energy. This isn’t exactly surprising: conservation of energy just means “there’s no unique time” and, well… there *are* unique cosmological times. Conservation of energy, on a global scale, is just something physicists “like” – you restore conservation of energy by adding additional fields which stored it in the first place, but you do that because you want the laws of physics to be time-invariant. There are other ways to describe the Universe which *aren’t* time invariant, and they’ll generate equivalent observations.

            But believing that a small metal cone, or any small-scale overunity device, is interacting with unification scale fields is just crazy. Is it possible? Maybe. But no one’s going to just stumble over the way to do it randomly.

          10. That’s just it isn’t it? The reasoning you’ve presented, (and statistical arguments) valid as they might be, simply will never yield a theory that will produce a functioning device at these scales – and that’s the real issue here. Yes, there are other ways to describe the Universe; IF you understand what is going on. Too often these are grasped at by those that don’t know that in the end these models are just not going to validate the notion that these devices can do what they claim, or that it is possible that they could. And that, in the end, is a consequence of the way the universe is structured. Semantic arguments just don’t cut it in this domain.

          11. Or shall we put it this way. “Who the hell are you to be the ultimate authority on how the universe is structured?”

            Anyone claiming that at this juncture is the fraud and liar.

        3. Why is it that people arguing against EM-drives almost invariably use genuinely faulty arguments? I’ve seen:

          * Arguments that it can’t work as it goes against physics laws. No, not “very unlikely to work as the mechanism would with high likelihood been detected before or even making the universe unlikely to exist in the first place” (which would be a proper argument if done in more detail). This is science as a religion.

          * Arguments that it would make a perpetuum mobile possible. Failure to understand that if it worked it couldn’t be one (see above: the universe wouldn’t be likely to exist if it were), as the mechanism is unknown one can’t blindly apply existing known mechanisms.

          * Arguments that as it sounds like something unscientific it must be unscientific. That is dogma, something that new discoveries have had to fight against for a long time.

          * Arguments that the tests are obvious failures not taking X into account. This is common from people that haven’t actually read which errors have been compensated for – argument from laziness.

          * Arguments that the tests actually proved that it doesn’t work – a.k.a. “the null-device produced thrust” argument. This is again from people that actually haven’t read that the null-device was a test if the cannea-drive hypothesis was right, not if a real dummy device would register thrust. Why listen to/read people that can’t even be arsed to read what the stuff is about?!?

          * Attacks on persons instead of the research. Bingo – that’s what you are producing. Guess it’s because you are a scamming drug addict yourself not wanting competition the next time you get out of prison yourself?*

          (* see others can also make insinuations without any backup from real-world data and post it – doubt that you will get the point though given your post history)

          The real arguments are that it is unlikely to work given our current understanding of physics and that the measured thrust is so tiny that it is hard to eliminate all error sources. The descriptions how the EM-drive and associated designs (Cannea drive etc.) are nowhere close to enough to describe how it could work, there are errors in them etc.

          1. Because those that support these notions cannot argue from the math and first principles. Ask yourself the question why is it those that can, that do understand, always fall on the side of rejection. Supporting arguments that give too much weight to marginal observation, and then assert that this might be possible evidence of new physics simply because they can dredge up what they think are examples from history where new discoveries were made under similar circumstances are not arguing science. Consequently applicable counter arguments do not need to address the science. I have not seen one good technical argument to date that supports the notion that this apparatus is doing what is being claimed, but plenty suggesting that the observations being made are artifacts of poor experimental design and execution.

            In fact arguing that events in the past in this domain stand as predictors is bordering on cargo-cult thinking – rejection of a novel idea in science by the majority is no guarantee that it will become mainstream in the future. The number of times that has actually happened is rather small. Even then, because Western mythos is heavy with the embattled iconoclast prevailing against the establishment, many of these stories of science revolutionaries are somewhat more sensationalised that the actual facts support.

          2. Actually the real argument is statistical: momentum conservation violation has such a tiny prior probability due to the level of our experimental verification of quantum electrodynamics (which incorporates the necessary symmetries that conserve 4-momentum (energy and momentum combined)).

            It would be extremely difficult to design a single experiment to be of such high quality that a positive result as small as that which was measured can multiply that prior probability to the point where we can consider our previous understanding of physics ‘uncertain’ in the common usage of that term.

          3. >”Western mythos is heavy with the embattled iconoclast prevailing against the establishment”

            The commonly used story is of Galileo.

            The irony is that Galileo was both a lousy scientist, and wrong. He couldn’t support his views by logical argument or empirical evidence, which is probably why they locked him up in house arrest for telling porkies and refusing to back off. He’s venerated now because he was going “in the right direction”, and because he advanced optics by leaps and bounds, but on the science of it he was really a full crank by any modern standard.

            The hypothesis that Galileo proposed was that the Sun is the fixed unmoving center of the universe (wrong) and the motion of the earth around this fixed point is what causes the tides by centrifugal action (wrong again). The problem was that his hypothesis predicted one tide per 24 hours instead of two, and he simply handwaved the disrepancy away by appealing to “shapes of the ocean floor”.

          4. Experiment trumps theory. But in this case the experiment is producing a signal of such minute magnitude, and inconsistently, leaving substantial doubt whether what is being observed is what the experiment is looking for.

    3. “it’s a device based on pseudoscientific theories backed by experimentally and theoretically discredited versions of quantum physics”

      I think you mean “experimentally confirmed and unexplained by current theory”

      ” They’re known to sometimes dip into the “free energy” sector”

      It’s not “free energy”. It’s a propulsion system that consumes a _lot_ of energy. Remember when people thought ion drives would never work?

      “or you become that much wiser and able to recognize the error that lead to the “discovery” in the first place.”

      Translation: “Hur hur hur NASA’s so stupid,I don’t believe something will work so anyone researching it is a moron.”

      1. >”I think you mean “experimentally confirmed and unexplained by current theory””

        I think you’re jumping the gun there.

        >”Translation: “Hur hur hur NASA’s so stupid”

        Not at all. They’d be stupid not to study these fringe claims because one out of a thousand might turn up something, and the ones that don’t are just good training for their researchers, because they work as test cases for their measuring aparatus and methods.

        Eventually, when they figure out what went wrong with the EM-drive tests, they’re that much wiser in how to measure these things and avoid falling into the same trap with other interesting stuff.

      1. The man is a perpetual bullshit mill when it comes to overunity devices, cold fusion, lifters, HHO gas, acetone in fuel, water powered cars, magnets in fuel lines… just about anything you can think of, he’s done it and for some odd reason there’s a whole bunch of people who take him seriously.

  4. The trouble is we have been through these “revolutionary results that threaten to overturn everything” a few times now what with FTL quanta, and Cold Fusion yet the status quo seems to survive. One result does not mean anything on its own and until this experiment is replicated several times under different conditions the question remains open. That doesn’t mean that something of interest isn’t happening, or shouldn’t be explored, but everyone needs to keep some perspective.

      1. Well of course. My only concern is that it is getting to the point where it is becoming difficult to get real science done in areas that have come to the attention of the crazies.

        Twenty-seven years later there looks like there might be something interesting coming out of the LENR field involving interactions of slow neutrons that while unusual and unpredicted, fall well within standard physics. Some of this may be important in predicting hydrogen embrittlement in certain metal alloys with implications in fatigue engineering (an area once of professional concern to me) It irritates me that I and others could not pursue this matter twenty-five years ago when I was working because it was too close to cold fusion and careers could be damaged by being tarred with any association with that idea.

        The results of this experiment may be nothing new, or due to error, or due to some effect that while novel, falls well within the bounds of standard physics, but if it becomes a cause célèbre of nutbars, it may be decades before someone finds out.

          1. True, but the problems start long before when you are looking to start these sorts of projects. Between the office politics and funding issues, its just not worth it especially if you are also putting your neck on the line. Furthermore it still doesn’t help when good science, like the discovery of cyclic water clusters, is leapt upon by the pseudoscientific rabble as justification for their notions. This too creates a chilling effect and limits the number of researchers that will get involved.

          2. plenty of solid science has been laughed at for decades before even other scientists took it seriously, it is an odd assertion to make that serious science would prevent that.

          3. Plenty people laugh, and plenty don’t. That’s how even the charlatans get funded.

            Good science gets picked up when it’s open and properly backed by theory and documented – reproducible. The fringe/pseudoscience is sloppy, poorly documented and non-reproducible / non-falsifiable.

            The real problem is that journals and publications prefer sensational and novel results, and so confirmatory or debunking papers get more or less ignored, and people who do science for money would rather publish ten weak studies that claim a new result, than one strong study that debunks any of it. That’s how bad science leaks through.

          4. Observations validate theories, not the other way round, cart before the horse there.

            The question of whether an observation is a true and reproducible observation is separate from whether it fits known theories.

          5. >”Observations validate theories, not the other way round”

            Observations are nothing without theories.

            >”The question of whether an observation is a true and reproducible observation is separate from whether it fits known theories.”

            Your observation depends on what you think you are seeing – your working theory. If you have no theory about what you are seeing, all observations are just meaningless noise, like shouting random numbers. Maybe they are lottery numbers, or bottles of beer on the wall – you don’t know because you have no theory about what they mean.

          6. A directed experiment does have some theory in mind, but often goes to prove it wrong. Then it’s either rejigging the experiment to get it closer to theory, or rejigging the theory to suit the experiment. Both of which is going on at present at the Large Hadron Collider, because there was a not quite perfect match to standard and alternate theories with the “Higgs Boson” result and they’re still trying to determine whether to fit the particle to the theory or fit the theory to the particle. Obviously refining the experiment and getting the errors and figures really nailed down with a body of supporting data would indicate that a real fact has been collected, and if that is still seems in limbo between standard and alternative models, then both of them have to give. But the more is learned it could strongly confirm one or the other. So in essence, they only started with a halfass idea of what they were really doing and the experiment validates either half of the ass or provides a whole new half an ass to put to test in another experimental series.

        1. ” It irritates me that I and others could not pursue this matter twenty-five years ago when I was working because it was too close to cold fusion and careers could be damaged by being tarred with any association with that idea. ”

          Oh god yes, there’s a dozen now “respectable” areas of physics that had “lunatic fringe” taint 25 years back, several of them piqued my interest then, but there was no way of getting near them. In many cases it wasn’t that the observation and experiment was particularly suspect, it was that they promised to do for a few thousand dollars what some big names in the field were getting multi-million dollar grants for, so they attacked them without mercy.

          1. You forget that things like Cold Fusion were actually tested by respected labs all over when it was first claimed, and they found the evidence lacking, and the lunatic fringe formed out of those who kept rejecting the rejection.

            There were many offshoots and branches in LENR such as the claim that sonoluminence is actually a form of cold fusion, and people did study these as well and they did get funding, and they were all in their turn shown to be just as bunk.

          2. We should just attach a generator to you guys circle jerking on everyone of these posts about the EM drive, boom free energy and enough hot air to propel us to space.

          3. Unfortunately we are entering an era where a very significant portion of the population, (in the West at least) is working under the impression that facts are what you want to believe, and if you believe hard enough, they will be true. In the past something like this would get its fifteen minutes and sink back into well-deserved obscurity, pursued only by cranks. Now it would not be a surprise if a movement to get this device launched into space gets enough traction to be seriously considered on pressure brought to bear by those who buy into this notion simply because they want it to be true. This is not how scientific research should be done, and it is not how public funds earmarked for research should be allocated.

          4. You forget that most of the tests were geared to one thing, proving it didn’t have the signatures of hot fusion, mostly fast neutrons. They proved that, the extension of that proof to claim that no novel, or unsuspected process was happening was specious. The few percent that were actually set up to find out if there was “something” going on, found something going on. As DV82XL mentions, continued investigation into what that something might be, has spun off some verifiable science.

          5. “They proved that”

            Of course they did. If there’s no fusion going on whatsoever, there’s no hot fusion either.

            The original cold fusion experiments were based on the idea that if you put deuterium atoms together close enough, you’ll increase the probability that they fuse spontaneously, and it was known that palladium soaks up hydrogen like a sponge to the point where you can get up to 900 times the volume of hydrogen in a piece of the metal.

            So the idea was that the hydrogen atoms are squeezed inside the crystal lattice under pressure to the point where they start fusing together. They started doing that by putting a rod of palladium in a vat of heavy water and running electricity through it to split it to oxygen and deuterium. Then they put a calorimeter around the vat and measured if the temperature increases. Assuming all the electrical input is used up to split the heavy water, the temperature increase has to be from fusion.

            Problem was, they miscalculated the Nernst equation and got the pressure on the hydrogen wrong by 27 orders of magnitude – cold fusion was not possible that way. Yet they measured anomalous heat production with their calorimeter. Several problems were identified like a dodgy calorimeter, recombination of oxygen and deuterium, faulty wiring with the temperature probe etc. etc. which could throw off the experiment and produce the anomalous results. The direct proof of testing whether the device produces neutrons was just handwaved away, and some people outright lied that theirs did and then later retracted it – few of the tests were replicated or documented properly.

            And year after year, test after test, people found that they sometimes got anomalous heat and sometimes didn’t, and the cranks latched onto all the test where heat was measured and ignored all the null results, basically doing bunk science.

          6. Basically, the same thing as with the EM-drive happened with Cold Fusion:

            The original theory was shown to be in error – it couldn’t have had worked that way – but it was too late. People had already latched on to the idea because they had a device that could be tested and which would by chance or by incompetence sometimes produce “promising results”.

            It didn’t matter that the theoretical bottom was out of the bucket – the pseudoscience of cold fusion was born because people started insisting that cold fusion IS happening and it’s just a matter of showing it. When the physics theory disagreed – out with the physics, “mainstream science is wrong” – obviously because you’re already assuming that cold fusion must be true so anything that claims it isn’t must be wrong.

          7. Yet still results happen, even though experienced researchers still persisting with it get only 50/50 reproducibility, something is going on…. yeah 50% success out of some quirky effect, you’ve gotta down the rabbit hole to research is crap, but if it was a cure for pancreatic cancer the FDA would approve it in a heartbeat, because this is the best science can do normally…..


          8. Or let me put it this way…

            You get 10,000 jars of water, how many do you expect to see anomalous temperatures in? Pretty damn close to zero right, even with ten thousand.

            Get 100 jars of fancy water, dangle stuff in them, attempt to account for every fraction of a joule of energy you might deliver, and get anomalous temperatures in 5…. that’s a pretty fucking big deal statistically.

          9. ” yeah 50% success out of some quirky effect”

            You can prove that prayer works by flipping a coin and praying for heads. There must be something going on, because you get heads 50% of the time.

            I can’t facepalm hard enough for your naivety.

      1. First you have to show that the thing actually worked on the ground. Otherwise you’re just shooting a copper kettle up to orbit on wishful thinking and, no matter how much the LHC did cost, that would be just stupid.

        1. I say let the crazies launch their kettle into space, instead of natural selection things become financial selection over time. They have been warned, and if they want to burn their money through a rocket motor let them! The irony is on them, dreaming about propellant-less propulsion and having to fuel a rocket with hundred dollar bills only to get their little satellite become another symbol of caveat emptor :)

          1. Can I opt out from paying it?

            >” They have been warned, and if they want to burn their money through a rocket motor let them!”

            I don’t want anyone wasting resources for frivolous purposes, because it’s you and I who’s ultimately paying it no matter who does it. Launch a $100 million rocket for no gain, and the whole economy just lost $100 million worth of man-hours, resources and energy that would have been spent elsewhere on something useful.

        2. The correct answer is “Taking all of those costs into consideration, the total cost of finding the Higgs boson ran about $13.25 billion.”

          “$61.2 million list price for a Falcon 9 launch”

          “First you have to show that the thing actually worked on the ground.”
          All of the studies (3) I’ve heard about say they created thrust.

          I made an electric motor but I can’t tell you how it works. You’re just not going to use it? That’s stupid.

          1. “I made an electric motor but I can’t tell you how it works. You’re just not going to use it? That’s stupid.”

            Are you serious? No company on the planet would take this bet. How do you plan and design with something that you have no idea how it works?

          2. [Pat]

            No company on the planet would take this bet. How do you plan and design with something that you have no idea how it works?

            The FDA does it all the time… :(

          3. “The earliest mention of the attraction of a needle is in a 1st-century work Lunheng (Balanced Inquiries): ‘A lodestone attracts a needle.’ ”

            At what level of understanding of magnetism do you think we should’ve started using the compass?

            Maxwell published in 1861.
            For the Standard Model “On 14 March 2013 the Higgs Boson was tentatively confirmed to exist.”

  5. Speaking as a physicist, I can definitely say that it shouldn’t’ve gotten through peer review without them having to explain why the forward thrust and reverse thrust configurations aren’t consistent – the reverse thrust configuration is many standard deviations lower thrust (per kW) than the forward thrust configuration. Which means the device under test is interacting somehow with the apparatus (it knows the apparatus/bench/chamber configuration).

    The data’s really, really poor compared to what they’re claiming. There’s no strong evidence of increasing thrust with power (their maximum thrust points were at the middle power consumption values), and the variation is way outside of what they claim they can measure.

    1. I agree, it’s simply not worthy of publishing. As long as the inconsistency remained and the variation is larger than assumed measurement error the experimenters (and reviewers!) should know there is something wrong with the *measurement process* and the experiment needs to be redone, nothing to publish until then… Its like publishing a paper that describes what the original idea for the experiment was but then halfway becomes a call for help “how is balance formed? how torsion balance is achieved?” then turns into a false nonchalance advice on how to psychovisually integrate transient responses from a torsion balance? wtf

      1. i think most people agree that the experiments until now have been anything but conclusive, especially considering the history of this device, but it would seem some people think that that means we shouldn’t continue experimenting, the really odd thing about a lot of these dubious claims is how hard it seems to be to prove them definitively wrong, the warp field interferometer from eagleworks suffer from similar issues.

        replication then explanation, to me, always seemed like the easiest way of disproving something.

        1. “the really odd thing about a lot of these dubious claims is how hard it seems to be to prove them definitively wrong, the warp field interferometer from eagleworks suffer from similar issues.”

          It’s because no one from real funding agencies believes this stuff, so people throw together tests from bailing wire and duct tape. And really, can you disagree with them? Regardless of what people want to believe, basically nothing in physics has ever been discovered by some guy randomly throwing together crap with no consistent theory as to how it would work.

          “but it would seem some people think that that means we shouldn’t continue experimenting”

          Do you randomly drop an apple every day just to check that gravity hasn’t magically disappeared? The US has an extremely limited research budget. Testing poorly-measured crazy results is just not a good use of research funding. There are *tons* of claims like this. You’d never be able to examine them all with good enough fidelity to get rid of them.

          1. “basically nothing in physics has ever been discovered by some guy randomly throwing together crap with no consistent theory as to how it would work.”

            False, Faraday started with just some kind of idea that electricity and magnetism might be related and did numerous experiments until he proved it. It was up to Maxwell to put all those results in a solid theoretical framework.

          2. Faraday at least had a phenomenon to study – he and others could make electricity and play with magnets even though they didn’t know how it all works. He didn’t start from an empty table and go “Welp, today I’ll invent electromagnetism, whatever that turns out to be”.

            The EM-drive believers don’t have anything. They don’t even have a proven phenomenon to explain – just a bunch of dubious test records and a lot of wishful thinking. They’re trying to invent a reactionless drive from nothing: by first attempting to observe thrust from some copper pot, and then explaining why the thrusts happens.

            They’re essentially just assuming that the EM-drive already works regardless of how it works, the thrust exists no matter how it’s supposed to happen, like someone would assume that magic is real and it’s just a matter of finding it.

          3. Wow, that’s a horrible representation of history.

            Before Faraday, Oersted had already discovered electromagnetism, and he discovered it by noticing that compasses deflect near currents. Note the difference: Oersted *observed something occurring*, and experimented on it, and even then it wasn’t random. That influenced Ampere to figure out a way to describe the magnetic field of a current-carrying conductor. That influenced Faraday to think hey, since currents cause magnetic fields, maybe magnetic fields can cause currents.

            Look at how specific *this* experiment is compared to that. Those were general observations. This is incredibly specific. They need a precision torsion balance, in vacuum, to even measure it and it’s not even being measured repeatably. There’s no way something like this would’ve been noticed by just tinkering – the effect is way, way too small. There was no basis whatsoever to think that this would work.

          4. “They’re essentially just assuming that the EM-drive already works regardless of how it works, the thrust exists no matter how it’s supposed to happen, like someone would assume that magic is real and it’s just a matter of finding it.”

            Yup. In fact, I’d say the sad part is that now there will probably be funding for some other group to prove/disprove it, and they’ll have to spend a bunch of money, and do a ton of careful investigation to show that it doesn’t work. Then the original guys will come out and say “no, you didn’t do it right”, then they’ll respond again, etc. etc. It’s a stupid waste of money. We’ve done it previously, with Pons and Fleischmann. It’s the same thing over again.

  6. Lets test it,
    but it in orbit, it falls down? burns up in the atmosphere ? it doesn’t work,
    it stays up there? it works.

    I can’t make up my mind if it should work or not.
    the laws of physics are pretty clear on this one.

    More tests are needed :)

  7. idk why this particular drive gets all the love.

    meanwhile mach effect thrusters also seem to produce thrust, theoretical explanations exist, and most importantly, the work is heavily peer reviewed. i guess thats more booring than “MAGIC STARSHIP ENGINE!!!”.

    1. Because it is barely more believable than “Wiggling vigorously causes mass fluctuations allowing a stack of piezos to inchworm through space”.

      Also, Woodward claims the EM drive works due to the mach effect.

          1. if you want reactionless you have to do crazy things. you might even be crazy if you think you can get any kind performance out of it. that said a woodward drive is so stupid simple to make attach a capacitor to a pc speaker with a hot glue gun and drive it with an arduino through a couple transistors. its a design that could lend itself to mems type devices and get a woodward drive on a chip. no big resonant cavities or magnetrons, and no gargantuan power requirements. perfect for cubesat propulsion.

  8. While I do love the fervor and attention that this thing has drawn to space propulsion, I am intrigued to see so many use it as a definitive case for a new realm of physics. I work in the field of electric propulsion (I build plasma thrusters for a living) and I must say that the paper in question fails to account for effects rendered by the chamber and test apparatus. We use a very similar test setup to the one mentioned in the paper (torsion pendulum and optical setup.) We use magnetic fields to shape plasma ejections and often need to calibrate the system by firing only the magnets, free of gases, to measure the chamber effects and account for them as we test realistic thrust from the plasma. One of our current pamfers (end cone for shaping magnetic field at the exit of our thruster) has a coil that produces 35 times more thrust than the EM drive. There is nothing near the thruster to push off from, but even a slight field will induce a magnetic current that produces very slight force, probably from the chamber walls or other equipment. It should be noted more clearly in rampant news stories that the thrust is minimal for the EM drive and that even magnetic charge at lower powers produces significantly more thrust. Peer review means only that the results were replicated and agreed upon, not that the thing produces magic thrust.

    1. “I am intrigued to see so many use it as a definitive case for a new realm of physics. ”

      There is a very vocal constituency of those on the margins of science, almost all of them wannabes that couldn’t make the cut, that believe very strongly in the notion that the Conservation Laws can be repealed. They live for the hope that one of their own, tinkering in a basement or a garage will come up with some device that will throw standard science on its ear. The leap on every possible mention that might be news of this being so and push it for all it is worth.

      They have always been with us. In a crueler era, Scientific American would publish the ravings of these deluded fools as letters to the editor in the April edition of the magazine for the amusement of the readers. Today they and their sycophants are all over the net.

        1. That may well be true, but I’m also an old one and it is depressing to realize that I have been seeing this nonsense argued now personally for over fifty years and it still isn’t dead. Furthermore it’s been going on for some centuries before in one form or another, with the same cast of the deluded, the gullible and the frauds. Once marginalized this crowd has grown, organized and in this and other pseudoscientific domains, have gained real political influence, and that gives me cause for concern. The attitude that all points of view should be treated with respect while valid in many areas, simply is not the best way to practice science where some ideas can be just plain wrong and those that believe them just plain fools. We do not do anyone any favors by pretending otherwise.

          1. Sounds like you’re pissed about quantum theory, fine, just for you, we’ll go back to Newtonian billiard balls.

            What has persisted for centuries is persistent railing against improved understanding on the basis of “That wasn’t what I learned in school” … I should damn well hope not, with the light of continued learning we’ve discovered it was facile and foolish.

          2. Apparently your ability to comprehend the written word is no better than your grasp of physics if that is what you think was the point I was making. The arguments you are extending based on your interpretation of the history of science are not new – every single person that believed in a device like this has made the same ones – I’ve heard them dragged out each and every time since I started to notice the over-unity brigade in my early teens. These are not arguments, if anything they are articles of faith, and as such carry the same weight.

  9. I already pointed out how conventional physics can explain it, radiation pressure from the asymmetrical emission of IR photons. At least one person understood and made some comment about solar sails etc. showing that they understood the principle. Except in this case we are having the radiator move itself as it’s output’s vectors do not completely cancel out. I also mentioned the relevance of fusion power etc.

    1. I don’t believe photon emissions can explain the thrust levels reported, or the asymmetry of the measurement of the normal and reversed configurations of the thruster. They’re more likely measurement error.

    2. Like the Poynting–Robertson effect or the Yarkovsky effect. If there is a real effect the magnitude is so small that it will be swamped by interactions with existing electric and magnetic fields along with radiation pressure.

  10. I do find it odd that people take such staunch positions on this device when it hasn’t even been fully tested. Initial results are hopeful but not conclusive. Insisting anything further than that is just ego or rhetoric.

    1. The sillyness of the situation is that nobody has a plausible working theory to explain why the device would produce any thrust.

      If you don’t have a theory, you can’t even explain why the copper cone. You might as well throw a spoon in a microwave oven and put it on a kitchen scale. You turn it on and if the needle budges you can say you have an antigravity device – why? Who cares – “the initial results are hopeful”.

      1. Unlike what you and your ilk knowing what to do to get a certain result without knowing the scientific reasons have been pretty common in the history. In fact many scientific discoveries began like that, something you should know if you actually took some time to research anything. Semiconductor engineering are full of those cases.

        1. Yup, Hall, Seebeck and others were finding things without solid theory appearing for 50 plus years after, though it was really the photoelectric effect that got the ball rolling on the quantum theory that lead to better understanding of semiconductors.

          1. Seebeck effect was discovered because the guy noticed a compass needle turning around his wires. It’s pretty hard to doubt a phenomenon exists when it can be actually seen directly by eye.

        2. In every one of those cases where scientific discover came from observation of an unknown phenomenon, the phenomenon they were seeing was clearly there. Nobody can deny a fact like getting shocked by static electricity, or getting an iron needle stuck to a lodestone, or accidentally discovering that a piece of rock had exposed a covered photographic plate due to radiation.

          The phenomenon was there clear as day for anyone to see: I urge you to present a single one where this was not the case – that someone just fucking around with a random teapot and some incredibly sensitive measuring equipment found a barely measurable effect that turned out to throw all the existing theory of physics out the window.

          This case is equivalent to people listening to satanic messages on records being played backwards – in the absence of a real signal and in the presence of random noise, you hear what you want to believe.

  11. This thing uses quite a bit of power to generate its thrust and I’m sure it heats up quite a bit… Are we sure this isn’t some effect caused by a difference in temperature? Something kinda sorta like a powered Crookes radiometer?

  12. Photons carry momentum. A laser or an led produces a thrust equal and opposite to the photons they emit. Each photon has hbar x k momentum so the conservation of momentum requires that to be the same transferred to the emitter, i.e., thrust

  13. My understanding of how Science is supposed to work says this should be studied.
    The job of science is to come up with constant theories to explain the observations.
    Find the measuring error, or fraud and the problem is solved, failing that start working on new theories.
    Saying this can’t be and holding up theory as proof is putting the cart before the horse, it would be like claiming lodestones can’t exist, and refusing to study them, because your current theories say that all physical reactions require some physical agency.
    Do I believe this is a real reaction-less thruster? No, but the anomalous measurements still need an explanation.

  14. A lot of this discussion has me thinking it would be interesting to have a “Journal of Experimental Error”, documenting experiments and measurements producing noteworthy but ultimately erroneous results. And a clear record of how the results went wrong.

  15. Okay, just throwing this out there…
    What if converting (most) neutrinos is possible, what would it take to prove?!…

    I think this ‘EM drive’ is complete bullshit, but I want to know exactly what is causing the disturbance. (Once again, slightly above standard deviation, something is happening…)
    Either figure it out and/or revolutionize current physics or, I dunno…
    We do need to know what is going on! I’m betting on interactions with the Earth’s magnetic field.

  16. Okay, so, I’m just going to leave my two cents here –
    First of all, there is absolutely no good reason for anyone to think that there is ANY chance the thrust efficiency will go up. Let’s be realistic; without understanding what’s going on, for all we know this is as good as it gets.

    Second – perhaps the wrong people have been looking at this, but this really should at least sound like an interesting application of well known classical/quantum phenomena? I suspect some level of media / layman interst has been fueling these suspicions of something beyond what we already know, but if you look at a few of the really crazy that we can already do these days, none of this should be surprising, I mean, hell, we built LIGO for however much money with however many tens of thousands of subsystems, and confirmed that everything we thought we knew in physics was still correct…

    My immediate reaction when I first heard about this from a friend was that oh, cool, so they did some sort of optical tweezer / photon thruster sort of thing, except they scaled up the wavelength to microwave frequencies. You see all of the necessary conditions you usually need at the nanoscale for laser tweezers to work (or more generally, to see practically meaningful forces from photons) – the system is close to the same order as a wavelengths, and there’s a resonant cavity creating very high field strengths. Conservation is not violated – it’s transferred using photons, essentially.

    Part two: now, if you’ve ever played with RF systems, you’ll also know it’s quite difficult to prevent RF from leaking where you don’t want it to go. At this field strength and this wavelength, it’s really not difficult for RF to leak where you don’t want it to go. In fact, I already see multiple likely candidate in the system, which seem glaringly likely. It kind of looks like most of the components of their cavity aren’t exactly precision machined parts, and my suspicion would be that these guys are not necessarily super experienced with dealing with RF waveguides and flanges. Look up “waveguide flange” on wikipedia for a proper, traditional waveguide flange meant to be bolted together. Note the precision machined (and thick!) flanges that are necessary to ensure perfectly coplanar mating of the flanges.

    Why is that so important? Well, it turns out the most popular unintentional antenna when attempting to make Faraday cages is, well, the slot antenna. It turns out RF radiation through holes in a metal shield is proportional roughly to linear dimension rather than area. So tiny vent holes in your shield are actually usually quite okay, but a solid metal block with an imperfectly flat flange can turn into a wonderful radiating structure, roughly at the wavelength of (un)interest. That’s why when you take apart your cellphone, you’ll see continuous silver conductive gaskets everywhere, or shield fingers, or whatnot. They help maintain a continuous shield, uninterrupted by any linear opening, even ones that are only a tiny gap apart. If you look at their flanges – the bolts are conveniently spaced close not too off (not like, an order off or something) of a half wavelength antenna for 2GHz (about 6cm). It’s also pretty thin brass (for a “conflat” seal, anyway – which typically requires a pretty rigid, thick metal flange that won’t warp when tightened, machined down to .001″ and probably something close to a mirror finish), and that’s probably easily being deformed into a nice array of antennas around the periphery. Incidentally, the side with more slot antennas is the side that gets more thrust…

    Anywho, so all you’ve got here is a low wavelength photon thruster. Unless I’m mistaken, there are practical limits to such a thruster. More importantly, without understanding what’s actually causing the thrust, it’s going to be awfully difficult for anyone to improve the system. I mean, gee, if you need more RF to leak on one side, you could just precision cut a slot on one side of the thruster, rather than relying on how tightly or how much dust the last guy putting it back together left on the flange…

  17. Wonder if the missing technical details/theory for this could be related to the missing technical details/theory that fleichmann/pons attributed to cold fusion back in the 80’s.

  18. The science and mechanism by which the apparatus works is indeed important. But for frig sakes, just launch one out in space and try it. It’s a new discovery. If it works, awesome. If not, that’s too bad.

  19. So, how is it if one substitutes “laser” for rf, it’s a no big deal thing?
    E.g. Solar power to collect light for use in water laser ( ) which can then be used to generate “directed heat exaust” or speed up dust gathered at front of craft for ejection out the back? Obviously, a liquid that didnt freeze in space would be more useful.
    “Theory is well defined” and would be faster than solar sail and/or could be a thermal addion to the solar sail. Isnt an extraordinary claim so wouldnt need extra ordinary proof to put into practice.

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