Hackaday Prize Entry: An EM Drive

As far as engineering feats of the 21st century go (as long as they turn out to be real), we’re looking at two things. Lockheed Martin might build a working, power generating fusion reactor in the next decade. That will solve every problem on the planet. The second is even more spectacular. It’s called the EM drive, and it will take humans to the stars. It violates the laws of physics, but it somehow works, and there’s a project on hackaday.io to replicate it.

The first thing to know about the EM drive is that it doesn’t use propellent. Instead, it simply dumps microwaves into a cavity and somehow produces thrust. This violates [Newton]’s third law of motion, “for every action there is an equal and opposite reaction.” Every rocket engine ever, from the Saturn V to ion thrusters on spacecraft now cruising around the solar system, use some sort of propellent. The EM drive does not; it simply dumps microwaves into a closed cavity. It breaks the tyranny of the rocket equation. If you strap a nuclear reactor to an EM drive, you’ll be seeing attack ships on fire off the shoulder of Orion, and C-beams glitter in the dark near the Tanhauser Gate.

Despite violating the laws of physics, Chinese researchers found this device produces thrust, and these experiments were replicated at Eagleworks at Johnson Space Center. No one can tell you why it works, but somehow it does, at least in the few tests completed so far.

If the EM drive isn’t just an experimental aberration, this is how we’re going to get to Alpha Centauri. Whoever explains how the EM drive works will get the Nobel, and [movax] over on hackaday.io is building one out of a broken microwave oven. It’s a fantastic project for the Hackaday Prize, and even if it doesn’t work, it makes for a great story for the grandkids.


The 2015 Hackaday Prize is sponsored by:

136 thoughts on “Hackaday Prize Entry: An EM Drive

  1. Guys. Tone down the hyperbole. Please. It really makes you lose credibility. This is noteworthy but let’s be realistic about how it’s being characterized.

    1. Hi,

      same thoughts here. A bit more caution in choosing the words – and not just copying from a yellow press headline – is advised.

      Also the insight that most people who tried to violate physics were violated by physics itself – when they thought they could fly without wings ..

      Blind faith and believe in everything that calls itself science is hurting the credibility of science.

      Science is about asking questions and covering up how and why things work.

      Many people need to learn a good deal of things, that having a PHD or being a professor does not hinder people to get unscientific, illogical, corrupt or even falsifying data.

      Remember how many times cloning from adult cells being reverted back into embrionic stem cells was “invented” in South Korea, in Japan, in China, in USA …

      And that actually when other scientists tried to replicate the results by using the same setup it did not work and that in the end it came out that the primary data was manipulated.

      And how often was cancer and aids declared curred by news paper articles that were written by people only copying the headline mashing up fill words and not doing the science.

      Even if somebody is not an expert in a certain field one can evalute the possibility of validity by testing if special terms(by the use of a dictionary) are used in the right context.

      Ethan Siegel[1] summed up pretty good, and he is asking the right questions.

      [1] http://www.forbes.com/sites/ethansiegel/2015/05/04/no-nasa-did-not-accidentally-invent-warp-drive/

      1. “The reasonable man adapts his beliefs to science: the unreasonable one persists in trying to adapt science to his beliefs. Therefore all progress depends on the unreasonable man.”
        — With apologies to George Bernard Shaw

      2. I’m sorry, but I really don’t that this article is too hyperbolic. Are there other articles out there predicting dates at which Star Trek will be a reality? Absolutely. This article, while stirring and exciting, does not draw focus away from the fact that it needs to be tested and proven. You can’t have a “then” without an “if” and you can’t have an “if” without doubt.

        Also, the article is specifically pointing out someone actually testing this experiment, so it’s further illustrating the effort that is being placed into testing this idea.

        I think the best part about science in general is making ideas happen. Yes, one needs to prove that something works consistently and also know how and why it works, but lets not forget that imagination is what got us to this point in history, for better or for worse.

    2. Agree. Nothing ever violates any laws of physics. This is simply a mechanism no one had ever thought of before. Once full characterization is complete, it will look as natural as any other law.

        1. Except its been tested in a vacuum….
          So right now, the evidence is that it produces thrust.

          But more testing is needed, find out WHAT is causing the thrust, then maybe whatever that is can be leveraged .

          1. the “thrust” is just above margin of error (ten times less weight then a snow flake) and it only showed up two or three time out of something like 20 tests. meaning the thrust can still end up being a problem in the equipment and not real.

  2. Microwave photons have momentum, just like any other photon. So they are dumping momentum into the device, then gaining more momentum until they drop below a given energy level. The device is acting like a diode in that the loss of momentum from the photons to the atoms is biased. Improving that bias will boost the currently very low efficiency.

    Now where is my Nobel Prize? And don’t ask me to do the maths, Al Gore didn’t get asked to do no sinking math!

    1. Seriously, I thought that was Physics 101. It is generating a propellent, just not one that is visible to the naked eye. If this was a violation of physics, then you would have to say the same about solar sails.

        1. Has it been tested in a Vacuum. Does it still generate thrust in a Vacuum ? I’m thinking that there could be some kind of standing wave vibration that steams air away.

          1. Maybe. I find it amazing that a guy reporting something on an online forum somehow becomes undeniable fact nowadays.

            Guys working for NASA can screw up, too. Wait until it’s published, or at the very least presented at a conference.

          2. result is surprising, no theory seems correct, but no artifact have survived experimental verification.

            today it is the classical battle between theory from white collar armchair physicist, and experiments done by blue collar experimentalists.

            history says that once it is replicated a handful times, the blue collar win.
            It will be hard and white collar will take 1-2 years to accept the reality after the business take control of the asylum.
            it can take 25 years before business enter the game… few centuries if there is no business (see oliver gordon de aberdeen and before).
            here I bet on 25 years, from 1st Shawyer’s work.

            This is pure experience-based prediction. ;-)
            It can goes faster if EmDrive take the bandwagon of the current similar revolution. (don’t predict, influence!)

          1. @Ed Minchau A Farady Cage does not perform the same function as a Helmholtz coil. Farady cages sheild against EMI, a Helmholtz coil generates a magnetic field that can be used to buck the Earth field…

          2. nasa test measured an effect of magnetic field by a dummy test,a nd they corrected it.
            http://nextbigfuture.com/2014/09/nasa-cannae-drive-and-emdrive.html

            “… of course the setup was also tested with a null 50 ohm load connected, in order to cancel the effect from the drives and detect any detect any spurious force due to EM coupling with the whole apparatus (which exists, at 9.6 µN) and this “null” spurious force was evidently subtracted from any thrust signal due to the drives then tested on the pendulum.”

            Shawyer made the test in many direction, to eliminate many hypothesis of artifacts.
            http://emdrive.com/faq.html

          1. How dare you destroy my ascii art HAD !
            ref…………………abs
            | ( – – – – – -*. . . . |
            | ) – – – – – – – – – x|

        2. What about if:

          a) Your house was placed in the middle of an ice skating rink
          b) You took a run up from one side of the bedroom and smashed yourself up against the far wall
          c) You then picked yourself up and walked back to the other side if the room again
          d) You repeated the process over and over

          Wouldn’t the house move inch by inch towards the other side of the ice rink?

          1. @ Pierce Nichols
            but EM waves can be reflected AND absorbed : one face is pushed the other is heated -> it moves.
            And if you look at Waxwell’s equations, it is clear that EM waves obeys nonlinear laws, that often have to be solved numerically btw.
            Friction when it occurs is often nicely modelled by a linear law at common speeds : it is however an irrveversible transformation as it produce heat.
            Photons have an interesting feature here : they can give 2x their momentum h*f/c when reflected and can be converted to heat when absobed. I think it could work like that, thanks to the heat loss.

          2. @lu

            — Learn what linear means in this context (not what you think)
            — Mark’s example only works the way he says because friction is most certainly non-linear, especially at very low speeds. The word you are looking for is stiction.
            — Heat is re-radiated, as electromagnetic energy. And it transfers the same amount of momentum as the same quantity of energy being absorbed into the material.

          3. @lu –

            If the crookes radiometer works the way you (and nasa) think it does, we have a serious theoretical problem on our hands. If reflected light imparts momentum then every power generator on earth is a horrific waste ( I am just crazy enough to enjoy this idea )

            “One of these things is not like the other ones, one of these things does not belong” – the thing we call light (electromagnetic radiation). Upon reflection (collision) there is no delay in light changing direction. It goes straight until it hits the mirror, then turns around and goes back the same speed without any delay at all (the collision and redirection of energy is instantaneous). Another thing that it does is change speed instantaneously between media (entering water in a glass, the light slows down in the glass and water and speeds up when leaving without any energy loss or time delay. Both of these things are completely impossible for mass bodies, light is not like the other things.

            If feynman logic is to be accepted (wave your hands and say “quantum effect”, “nothing to see here”!) then we are all wasting our f*ing time with every known energy generator.

            Conclusion – If light both imparts momentum to a mirror at reflection and continues on at the same wavelength and amplitude after reflection (it does) then the ultimate free energy device is a few design cycles away from reality (which i do earnestly hope is the case). Unfortunately i find it is much more reasonable that the wifi router, microwave, and laser generate no recoil and momentum couldn’t be generated with massless light in all the years between now and infinity. Please experiment and get back to us (also please remember we are talking about REFLECTION, at absorbtion a photon can do all sorts of things)

            check out hyperflight.com, but steel yourself against the crazy.

    2. What about combining multiple microwave emitters focused on the same point but with resonating frequencies? Or any other combination, like symmetrical waves etc that can provide momentum amplification. There’s much space for experimentation here. Hey use 4 and play goa-psy trance on them and see what happens!

    3. If the microwave source and feed lines are not part of the test apparatus on the force balance, photon pressure through the feed line might easily account for the force observed.

  3. There’s no mystery about the fact that photons (including microwave photons) have momentum. You can use a laser as a space drive… and it would work better than this turkey because all of the photons are (more or less) going in one direction and none of them are being reabsorbed and turned into heat.

    The amount of thrust produced per unit energy is tiny (thrust is power divided by the speed of light). It’s reasonably easy to demonstrate that any drive system that purports to do better than that without using reaction mass violates conservation of energy in any region of curved spacetime… and all spacetime is curved.

    Here’s how you do it. First, realize that curved spacetime just means a gravity field. Let’s start with Earth’s, since we live here. I’ll show a specific case then use induction to prove it’s universal. Let’s use round numbers… g = 10 m/s^2 and a drive that produces one kiloNewton per kilowatt. Let’s specify that our rig masses 100 kg (weight 1000 N) and is fed with 1 kW of power, so the weight is exactly balanced by the thrust. Let’s also pretend for the sake of easy math that air resistance doesn’t exist.

    Now let’s give it an upward velocity of 10 m/s. We’ll define the starting height as 0m, so the initial potential energy is 0 J and the initial kinetic energy is 5 kJ. Now let’s wait 1 sec. The drive has consumed 1 kJ, the kinetic energy is still 5 kJ… but the drive is now 10m higher than when it started, so it has gained (100 kg * 10 m/s^2 * 10m) 10 kJ… for a gain in energy 10x the energy input! Fuck going to space, we’ve just invented free energy! (Not really)

    Now, it should be clear that even if the drive is much less efficient, we can just pick a higher initial velocity and still gain more potential energy than we expended in the drive. Of course we can’t pick an infinite initial velocity… we’re limited by the speed of light. And what efficiency maintains energy conservation? Same place we started: thrust = power/c.

    We’re done here.

        1. Trust and believe you’re not the only one. I mean, I can see where they’re trying to go with it (ion drives do work), but then they are just going completely in the wrong direction by making the leap of logic without the logic (or science for that matter). If we keep trying to skip the immediate steps and say that we have achieved holy grail of goals that violate all we know about physics, we end up holding back. Hell, the leaps and bounds we make are grounded in them. We didn’t just skip from Maxwell’s equations to SR, there were steps in between to support the transition. And those steps even helped us to leap to quantum mechanics, which is still a mess but at least people are admitting it.

        2. The source of the irritation for me is that people imagine a lack of energy conservation would be a good thing. A universe where a few magnets and wood can break energy conservation and produce arbitrary amounts of power would be a universe where this could also occur naturally, which sounds like it could really ruin your day.

    1. Your line of reasoning really makes no sense, because you’re simply asserting that the velocity doesn’t change when the object gains altitude. The energy you gain comes from decrease in the starting velocity AND the thrust provided by the device. The violation of conservation of energy comes simply from your description of it.

      Start with the system without the EM drive component and you get a simple ballistic travel. The object with its intial velocity reaches an apogee and then turns back. Kinetic energy turns into potential energy and back.

      Add the EM drive, or add 1 kJ of energy every second, and since the potential energy is m*g*h where m and g are constants, the object slows down until it reaches a final velocity of dh = dE/mg or v = P/mg which turns out to be exactly 1 m/s in this case regardless of the initial velocity.

      Thrust is not power or energy. Power is a result of thrust multiplied over speed, and energy is thrust over distance. W = Fs : That’s why it’s completely wrong to say that 1 kW of power equals 1000 N of thrust.

      1. I deliberately set up a situation where, if the device produces more thrust per unit energy than a laser, you get violation of conservation of energy. The fact that it is possible to do so proves that the device can’t do better than a laser. The technique is called proof by contradiction.

        1. Read the articles on this thing first. NASA and others have indicated that the drive far outperforms simply throwing energy (laser, microwaves) in one direction. For some reason.

    2. So, as far as I can tell, you’ve just explained how an engine can’t expend less energy than the kinetic potential energy of the object it’s raising. Congratulations? I guess?

      I don’t see how this is relevant to the EM drive, and even if it were, what’s weird about it is that JSC has reproduced the effect but can’t explain it with standard physics.

      1. “reproduced the effect” is an overstatement of the matter.

        The results they’ve had were in a sealed but not evacuated chamber which doesn’t preclude effects like heat imbalance causing differential gas pressure

        But the main probem was that their null hypothesis test – the configuration that wasn’t supposed to generate thrust according to the EmDrive claims, did produce thrust, indicating that the thrust was an anomaly of the testing setup rather than the drive itself.

        1. To elaborate: imagine that you put two identical EmDrives face to face and power them up. You’re not supposed to get any net thrust, yet the torsion pendulum starts to swing around.

          Well obviously something fishy is going on there.

          1. Because reporting things in an online forum post makes it totally true and beyond question. Completely valid way of reporting scientific results.

        2. *sigh*
          The Null test that generated thrust wasn’t a dummy test – it was a test for a hypothesis of how the device worked.
          The fact that the null test generated thrust just means that _that_ hypothesis was wrong, not that the em drive doesn’t work.

          There have been proper dummy tests that haven’t generated thrust.

        1. Why is it a violation of Conservation of energy?
          Just curious since they are converting electrical energy into kinetic energy… so energy is just being converted not lost…

          Now if a laser produces thrust, does a laser loose mass for every photon it sends out? if not, isn’t that a violation itself?

    3. I’ve read your comment and it has no flaw. Simple and concise. However, I’m trying to find a workaround your argument.

      Let’s assume your hypothetical device, somehow, obeys the conservation of energy. How? By dropping its efficiency as soon as it has some velocity with respect a conservative field (for instance, a gravitational field). In your mental experiment, the rig would go upwards losing kinetic energy until it reaches velocity 0, at which point the drive will provide thrust at its full efficiency and will keep the rig stationary.

      I know, it sounds arbitrary and made up, but would it still violate the law of conservation of energy?

      I’ve noticed that in their FAQ (http://emdrive.com/faq.html) they state that the drive loses thrust as the velocity increases (question 7). It is a little vague, but maybe it is accounting for this issue?

      1. If the device worked that way, it would pass the quick energy methods test. However, it still wouldn’t make the EM drive more plausible. It would imply that the EM drive was somehow reacting against the gravity field, which would still demand entirely new physics. Nothing that the EM drive folks have actually done has produced evidence equal to the magnitude of that claim.

  4. Let’s hope it doesn’t leak or he might not be showing any grand kids either way.
    Personally I hope he does find out if it works or not. We could do with some “new” physics from somewhere, either in physics or chemistry. There have been so many advances lately but most out of the range of the average tinkerer. Perhaps a new ere of the Victorian garden shed style inventors is in order.

    1. If he gets the resonance and angles just right, perhaps even increasing reaction area, he might increase efficiancy enough to be a little more viable.
      Maybe a slightly different drive freqency, you’re relying on what’s around you down here. You need to think what’s around you out there. Tesla made that first pioneering leap, knowing the world was not yet ready. Keeping it simple doesn’t have to mean sticking with what’s available.

    1. Indeed. Our models of reality are inferred and incomplete. Just as an atom isn’t explicitly as defined by the Bohr model, with little balls orbiting a grouping of other little balls – but the model helps us gain an understanding of the practical function of the object under study. The hubris is believing that reality is defined by the model. This is just not so, and it is fallacy to believe that the model – by definition a simplification of a complex system – is able to replicate in every way just that – a complex system.

      1. Tell that to people who *believe* that human activity is the be all and end all, maximal driver of climate change, despite the fluctuations in output of the massive natural fusion reactor this planet orbits. Despite the facts that the computer models they’ve put together have *never* come close to predicting what’s actually happened after announcing their predictions they still *believe* they can use them to predict the future 100+ years from now. Despite the fact that the known history of all types of cyclonic storms around the world shows only chaos, no trends in any direction for number, size, strength etc, they still insist there has been a huge increase in the past 40~50 years. Despite the research proving that many low lying islands have suffered erosion on their sides facing water currents and prevailing winds, with corresponding buildup on their leeward sides, and have had land subsidence from overdrawing of fresh water aquifers – they still *believe* it’s all due to “sea level rise” that rather curiously has not been seen at all at various tide gauges firmly attached to solid bedrock.

        It’s not “denial” or “skepticism”. There’s just a long list of factual observations that contradict the *belief* that there’s a runaway warming or change of Earth’s climate, which has steadfastly failed to run anywhere.

        1. I’m going to make this as dirt simple as possible. Imagine two ice cube trays. One containing regular water, the other has water with some kool-aide mixed in. Take both trays and put them in the freezer until they are both frozen solid. Take them out. Now, try to empty both of them into different jars by the usual method of twisting the trays. You will automatically notice the the kool-aide tray doesn’t require that much force to get the cubes out. This is due to the kool-aide preventing the water from forming its normally strong crystalline formations (some do form, but not as much). This will tell us that the kool-aide cubes are weaker than the cubes that are just made of water. Now, with the cubes in two jars, which of these two set of cubes do you think will fully melt first when expose to room temperature? That’s right, the kool-aide cubes, and for the very same reason. It doesn’t take as much thermal energy to break these formations that are already weak to begin with.

          Now, what does all of this have to do with man-made climate change? First, the kool-aide that was mixed into the water represent the particulates that humans have released into the atmosphere that was in the ground. The “mixing” occurs in the air and it drifts to the poles where they condense to a sheet of kool-aide ice. This top layer accumulates enough that it starts to compress under its own weight. The bottom of the kool-aide layer gets a better grip on the pure ice but is still weaker. Now this weaker ice is melting at a lower temperature (and the pressure is helping to do so) which can “cut” into the pure ice creating fissures and cracks that weaken the overall structure of the rest of the ice sheet below. Enough time, a slight warming and we have whole ice sheets falling.

          What’s even worse is that the dilution of the ocean water due to the pure ice being melted into it decreases the salinity of the oceans. This can actually affect the ocean currents that actually help to distribute the energy given by the sun. If this is not properly distributed, there would be places that are hotter or colder than they should be. This also affects weather due to the change in the amount of heat necessary to evaporate water. And before you can say that’s all bullshit, need I remind you that your sweat has salts in it to allow your body to cool down by facilitating the absorption of heat by rapid evaporation.

          1. Actually your sweat has salt in it because there is no such thing as a free water pump at the cellular level. In humans, water is moved by pumping salt (sodium and chloride ions) across a membrane with the water following osmotically. The water in the sweat evaporates on your skin leaving behind the salty taste !

            I agree the colligative property of salt in the sweat also raises the phase change temperature of sweat (and thus enhances heat removal), but the physical reason salt is found in sweat is to make evaporative cooling possible at all, as transport of water would not even occur without it.

          2. @JoeS

            I’ll go along with that. I just wanted to point out a personal example of how the salinity of ocean water helps regulate global temperature. Besides, after being in a desert climate for a year overseas, not seeing salt crystals on my body is a wonderful form of blissful ignorance that I welcome most highly.

    2. I wonder, since it doesn’t appear to rely on clasical action and reaction as we usually see it, perhaps it is fue to the wave form being confined in a resonant cavity and thus producing a stable structure across time as opposed to a stable structure in space. That repeating patern then inducing a secondary force.
      Maybe they need to look at something akin to electromagnetic super cavitation in order to reduce friction in space if they can’t yet find a viable way to increase the output.

        1. Neither is ignoring experimental results – science is the result of detecting and then modeling things that goes against our current understanding.
          Verifying and making sure there are no significant measuring errors in the experiments is the way of the scientist.

          Many that complain about these results doesn’t use science as the method it is but instead uses it as a religion.

          1. They’re make a truly extraordinary claim on very weak evidence. The fact that they don’t acknowledge how big the claim they are making is should lead you to believe that they are most likely mistaken.

          2. Pierce, that’s why having an independent team attempting to replicate the experiment, as is being done on hackaday.io, is so important. We know for a fact that the standard model is incomplete; it doesn’t include gravity. The data trumps any model. If the HaD.io team replicates the device and reports thrust, then it doesn’t matter what conservation of energy or conservation of momentum or any other physical law says. We call them laws because there are no exceptions – until there are exceptions

            It is nearly certain that the laws of nature as we understand them will hold when the HaD.io crew gets its device built; they will almost certainly not detect thrust.

            However, if they do detect thrust, good! It would mean at least one of what we think of as physical laws is not actually a law of nature at all, but a sort of second-order effect of something else. And that might finally lead to a deeper understanding of the universe, and a way to include gravity in the standard model.

          3. @Ed: Difficulties with the standard model are not evidence for the EM Drive, nor are they the fundamental problem with it. Breaking conservation of momentum fundamentally means breaking conservation of energy, as I showed earlier. And that’s a much bigger claim than attempting to wedge something into the gaps in the standard model.

            There’s no-one on the HaD.io team who appears to have the skills to make a credible measurement at the force levels involved. I don’t think any of the teams that claim to have replicated it do either. Accurate measurements at that kind of force level are extremely difficult, because the list of confounding factors are as long as your arm. The fact that the device consumes a great deal of electrical power makes the problem far worse, because generating 50 uN of force from magnetic interactions between conductors can take as little as a few milliamps under the right circumstances. Hell, getting that much force out of interactions with the Earth’s magnetic field only take an amp or two. What that means is that a carelessly routed power cable could easily produce the effect that they have claimed to observe. Or about a million other things. If you’re claiming to break conservation of momentum, it’s up to you to prove that none of those things are causing your observation.

            And I don’t see the kind of exhaustive analysis required to rule these sorts of effects out in anything that’s been published on the subject, nor evidence that such analysis is required. Or anything that even remotely resembles awareness of how big the EM Drive claims really are.

          4. Pierce, might I suggest that you are perfectly positioned to perform the experiment yourself? You’ve come up with a number of objections, so I’m sure your experimental setup would control for those very objections. And if you set it up and run it and conclude they’re full of BS, you’ll have actual data to show.

    1. I doubt it.

      1: It’s almost certainly crap.
      2: Even if it isn’t, it’s phenomenally inefficient. It realistically is only going to be useful in space situations, and even then only NASA-type (long-life) missions. Stationkeeping for satellites is going to be more useful to just use propellant.

      But you have to realize: this is being pushed by a group at NASA that is also reporting *another* “weird physics” effect ( the warp interferometer ) that’s totally unrelated. And also only useful to NASA. And they’re somehow magically related!

      So let’s review: you’ve got a group that’s claimed to discover something that doesn’t make any sense, that’s only useful really to NASA (so it looks *great* on grant applications), employed at one of their own labs (so there’s going to be less credibility skepticism). You can draw your own conclusions, but I would bet on effects disappearing.

      1. I should also add: in those tests, lots of caveats are thrown around about lacking funding for “proper” testing. In other words, there’s strong (financial) incentive to see positive results. Don’t get me wrong: I’m not suggesting forged results or anything. But finding the source of a tiny unknown effect when there’s no incentive (in fact, disincentive) to find it is really, really hard.

      2. Points taken Pat, but the first word in my post is ‘If’. But I do think, that if there was a remote chance of a spacecraft drive that operates without the need for expulsion of mass and seems to violate some long-standing laws of physics, that somebody would be throwing money at it and keeping it quiet. Please note use of ‘if’ in the second sentence.

        1. You don’t understand science – it isn’t a religion. It is a method of successive approximation of a model to measured results giving a better model as a result. The laws of physics are just a model describing our understanding of reality.

          IF* these results are correct our understanding isn’t complete – and that will improve the so called laws of physics! While I’m not one of those that uses the word “quantum” as a magical phrase our understanding of the border between quantum physics and relativistic physics is a known unknown.

          (* I’m not saying it is but so far we have at least 4 experiments indicating there is something novel happening)

          1. Extraordinary claims require extraordinary evidence… and claims that violate fundamental conservation laws are the most extraordinary claims of all. Their evidence is laughably thin for the magnitude of the claim they’re making.

          2. Hey remember when superluminal neutrinos were ‘detected’ at CERN? Incidentally, that team involved had run 4 different experiments and got the same results each time, flying in the face of established knowledge.

            Turned out to be a loose cable and some other stuff. They did their due diligence publishing exactly what went wrong too, which was good.

            Let’s wait and see what happens this time. Hey, maybe they could get funding on Kickstarter?

          3. opera FTL neutrino were just one instrument, one clock…

            here it is 4 teams, and 6 devices.

            about magnetic field, it was measured by a Nasa lab, and corrected.
            the way to correct it was to test with a dummy (a resistor, not the null fetta) and see the effect.

            Shwayer tested even more
            http://emdrive.com/faq.html
            as he changed the position and direction to eliminate some artifacts.

            note also that the effect is clearly appearing only with resonance, so it eliminate many proposed artifacts.

            if artifact it is a microwave resonance effect. not impossible, but it will be a discovery, maybe useful.

        2. @pierce – It’s tricky business remaining skeptical yet still open minded enough to discover. I believe it to be related to the reason why most theoretical physics breakthroughs happen before 30 (and then not again, despite best efforts).

          I am torn. On the one hand I agree that there isn’t time (or funding) to do every experiment, and we should employ rational means to eliminate the ones we are certain would be only wasteful. On the other, all experiments with anamolous results, inconsistent with prevailing model/theory, and multiple verification from seperate legitimate scientists I should think would be worth further study without too much more merit.

          Unfortunately, the more “certain” we become (an unfortunate side affect of aging, it appears) the less likely that we will make scientific progress, and our measure of “what is a reasonable or worthwhile experiment” is more and more marred by the wish that our conception of the world be correct undoubtedly to justify the life we lived and actions we made in the light of those beliefs that naturally mutated from the facts, models, and theories of our youth. More exists in heaven and earth than does in our (natural) philosophies, and most regrettably for your position the negative statements you are positing (this result couldn’t be, my model of reality dissallows the potential possibility for such a thing) requires the totallity of all knowledge to verify, or even defend. Scientists may only make partial positive statements relying on many suppositions and contingencies, absolutes are for the priests although asymptotically “absolute laws” are suggested.

          All that said, I also find the lack of sufficient magnitude of the “anamolous thrust” highly suspect. I’m not a fan of coincidence and the fact that the thrust is so extremely close to the margin of error for the measurement devices being used (and the setup is in no way simple / reduced to examine principle) screams that this is nonsense. However, your assertion that an effect like this, if real, would necessarily be a violation of momentum/ energy conservation seems to me to be nonsense as well. All we would have to do is discover and describe a method/mechanism of/for converting a different form of energy (microwave, perhaps) into momentum and we would have no violation required.

    1. Nah – the first time I saw this it was on nasa.org I think! Or maybe the JPL website – a few years ago.

      It probably works a little – the principles seem familiar enough as noted by other commenters.

      It may be pretty much a lot of hype in the end, or it would have been more fast-tracked by now.

  5. Finally built a quantum interference drive did we? (technobabble ftw) or to be rude and steal a quote from gizmag ,”30 and 50 micro-Newtons. This is a tiny amount, only enough to levitate a mass of three to five milligrams”. However, if it does work, however it works, will it scale up?

    1. Beside the critics in theory, there is no interesting fact in that paper. calling it fraud is …. a fraud.
      it is just armchair critic based on theory.

      I’ll please you, I don’t believe in Shawyer’s theory… I respect just in the 4 replication, as needing more research.
      https://www.reddit.com/r/Futurology/comments/34cq1b/the_facts_as_we_currently_know_them_about_the/

      I follow the MiHsC theory of Michael McCulloch, until I see a better one.
      http://physicsfromtheedge.blogspot.co.uk/2015/05/mihsc-vs-29-anomalies.html

      discussion on theory is fun but premature. we need more experimental data.

      If you have serious data on the 4 experiments, I will relay to interested parts.
      That is my job ;-)
      http://www.scoop.it/t/emdrive

    2. Eh, in Biology we get a lot of perfectly valid messy theories. The Standard Model still seems like a bit of a kludge too, but it did pull off some good success lately.

      Points seem valid in that PDF though, and I thought this was a good general thought : a genius is someone who produces something everyone can understand.

  6. This is just like cold fusion, there is something happening that we can’t explain. If we hype it we can get more money to investigate it on the off chance it will change the world. The burden of proof is on them to prove beyond a shadow of doubt that this thing works. A good explanation of how it works would also help.

    1. Many teams tried to replicate Pons and Fleischmann’s results and none succeeded. The first clue was of course that Pons and Fleischmann were still alive, which they shouldn’t have been thanks to neutron flux from their unshielded experiment had they created the amount of energy they claimed through fusion.

      1. This is a myth.
        Cold fusion (LENR) was replicated, just in more than 40 days as 2 influential labs imagined (MIT, Caltech)… It was also replicate dmostly by competent people, chemist. Physicist are not cometent in such calorimetry (much above their level).

        physicist searched for what ther was nearly not, radiation, neutrons, tritium.
        There is tritium, and BARC (indian nuclear lab) replicated it wall, like many US gov labs, Texas AM, Amoco…

        this video is short and gives the essential.

        McKubre (who did among the best experiments, isothermal flow calorimetry) explain that urban myth
        http://www.currentscience.ac.in/Volumes/108/04/0495.pdf

        today cold fusion is massively proven, replicated,
        http://www.currentscience.ac.in/php/feat.php?feature=Special%20Section:%20Low%20Energy%20Nuclear%20Reactions&featid=10094

        it is even beginning an industry story
        http://elforsk.se/LENR-Matrapport-publicerad/
        http://www.lenr-forum.com/forum/index.php/Thread/1337-LENRG-G-Day-Milano-Airbus-and-LENR/

        note that new technology in LENR is NiH, cheaper and more powerful than PdD.
        Much less scientifically replicated, because it get commercial venture at first results.

  7. “There is no finality of growing science”, “There is not self containing theory possible aside apart from practical meaning” – Oliver Heaviside
    Newton’s 3rd law stands, as it brings a fundamental understanding of the visible for forces round us, but the REaction force can be made to act in any direction even seemingly in that of the action force through a concept called “a virtual ground”. And one who understand that science is not based on theories but on understanding the practical natural phenomena, even if they seem not agree with established theories, will try to explore all validities as theory must follow experience and not vice versa.
    An good read in that direction, supplied with a wealth of practical phenomena:
    http://magneticuniverse.com/uploads/FileUpload/e4/24d9314e3aa202313fd3cf4259d19e.pdf

  8. About the only way this could work is by distorting space/time in such as way as to contrive a ‘push’.
    Picture this: momentary dilation of region of space/time, which shoves matter aside. Two things can’t be in same place, same time and all that. Space/time ‘bubble’ transitory thing. It expands, collapses. During collapse, flash of light, thermal radiation.
    Longitudinal Ampere forces seem to be doing something similar [arc-gap repulsion, water-arc explosions, rail-gun hammering] in action.
    If space/time ‘bubbles’ were to impinge on some object, it would be moved along.
    There is no recoil from the arc-gap [or it can be symmetrically canceled out] so the net result is acceleration without reaction mass.
    Unless space/time could be counted as reaction mass?
    Project Orion on the micro-scale?

  9. What the absolute hell guys. What the fuck is with this clickbait article?

    As has been said in every single sane discussion of this thing: The observations are odd. Therefore we should keep testing. But there is a near negligible chance that this is new physics. Like FTL neutrinos it’s far FAR more likely that there is an unnoticed systemic error in the experiment. Like maybe they forgot to stick the damn thing in a uniform magnetic field and the 2KW(!) of energy they’re dumping in is causing the thing to become an electromagnet. Maybe some of the capacitors are offgassing, or some metal is ablating somewhere. The force is so small that these errors can easily account for everything.

    I’m pretty disappointed that hackaday is promoting shitty science. Get your act together Brian.

    1. HaD is not promoting shitty science. The first link is to someone who is trying to replicate and evaluate the device – that is, seeking to replicate the results.

      That’s the very essence of science: come up with a theory and an experimental setup to test it, get some results, and then other people try to replicate the experimental setup and see if they too get the same results If they do not get the same results, the theory must be modified or scrapped.

      Remember, the map is not the territory, and the Standard Model is, like Camelot in Monty Python’s Holy Grail, only a model.

      1. Exactly. But the strong opposition from people that haven’t bothered to even read the published results (evident by the claim that a dummy test produced thrust – which is clearly wrong) and don’t think the scientific method should be used for claims that goes against the “laws” of nature.
        Or in other words: science worshippers that doesn’t have an understanding of the scientific method.

        It IS to early to claim we have something genuinely new on our hands and we HAVE to have a strong model to describe it – but that is obviously premature without more experimental data. Requiring a good explanation of the model at this early stage is, once again, a case of worship of the existing “laws” and not anything to do with science.

        1. I have read the published results… with the skeptical and analytical eye that you clearly failed to apply. The claim is extraordinary, the authors never really acknowledge how extraordinary it is, and their analysis section writes checks their evidence can’t cash.

          1. Then ignore the analysis? That the analysis is speculative and/or poorly supported by experimental data at this point of time isn’t strange – we are talking about something that apparently goes against our understanding in a relatively well researched area. The analysis are at the “fling shit” stage.

            I don’t see how you conclude I’m not skeptical? I AM! I don’t think the results will hold up, I don’t think the currently presented alternatives of how it could work are realistic and I don’t think measuring errors are controlled enough. But the proper way forward isn’t burying ones head, it is to try to eliminate possible error sources and continue testing prototypes.

            The thing is that we have 4 parties that have tested the principle, all of them have produced what is looks like an anomalous effect.

  10. This could be revolutionary if it is true. History tells me to be cautious, but real test are going on right now.
    If the head of NASA Advanced Propulsion is optimistic then i am too

      1. yes but the best test would be to make a miniature version (like a cubesat) launch it and test it 12-24 months… if it works then a new world begins. Elon could do this …

  11. I can’t help but wonder if this is a simple function of geometry. Maybe the momentum is moving in a pseudo-triangular fashion. One wave bounces off the thrust wall and the remaining counter waves bounce off the other two walls simultaneously cancelling out the reaction momentum.

    1. Sigh. No. That’s not how momentum, photons, EM waves or angles work. Think of it this way: The photons hit the flat wall, transfer momentum and generate their tiny force. They then fly back and hit the triangular wall, bounce off at an angle. They transfer momentum to the sloped wall, generate a tiny opposing force.
      You might go “ah! it’s less force than the first wall! Net force!” That is wrong.
      The photon still has momentum left! It’s still moving away from the flat wall. Eventually it will hit the triangular side again and again, until the rest of the momentum is transferred and the forces equal out.

      All those details aside, the measured force is waaaay higher than photon pressure could possibly provide. Photon pressure is /tiny./

      The stated theory says some QM or SR weirdness is going on, but nobody other than the builder seems to believe that.

      1. This thing is ways too big for Quantum mechanics. This thing is ways too small for the General relativity. And this thing is ways too slow for the Special relativity. What can I do with it? Remove the cone and warm up my lunch as usual.

    1. Newtons laws were written without reference to reference frames. According to the inventor when you factor in the laws of special relativity, Newtonian mechanics is not being violated. When i find the time I’m gonna bone up on inertial reference frames and what the definitions of closed and open systems are.

    2. People probably made sarky remarks about the Wright Brothers’ plane, that only flew 10 feet up and 100 feet forwards, or whatever. Compare it to a jet fighter. It might be this is a really fantastic principle that needs a bit of extra thought to turn it into something interstellar. So far it’s just a tantalising little “wait a minute…”

      If people can compare it to all the known laws of physics, and none of them explain it, then yes it is violating all the known laws. Just means we’ll need a couple of new laws. That happens all the time, historically.

      Or it might just be a glitch, and it doesn’t work at all, and we’re all disappointed. Tends to be the case with most miracles like this. Still definitely worth investigating, even just to learn something, even just to learn where we went wrong in understanding it.

      1. Just read Scientific american laughing at Wrigth brothers
        http://invention.psychology.msstate.edu/inventors/i/Wrights/library/WrightSiAm1.html
        or New York Time ridiculing Goddard
        http://astronauticsnow.com/history/goddard/index.html

        notice how anomalies are impossible to publish until it is very very clear and interesting industrialist
        http://www.mosaicsciencemagazine.org/pdf/m18_03_87_04.pdf

        the hypothesis of a glitch is still possible, but after 4-6 replications done with independent teams and instruments it start to be really improbable.
        Reconsidering our theoretical assumption (I think that CoM/CoE will survive with just new factor integrated, and maybe a total rewriting of physics with more quantum and more relativity, not less)

  12. I read the paper and to me it seems that it causes an inverse wave bubble effect that charges the surrounding photons into an excited state and then funnels that through a small exit opening, causing thrust. It also seems that there may be a type of resonance happening to the chamber walls that also excites said photons, also causing thrust. I have to do some more research but I think that is basically the jest of it.

  13. New from:

    http://www.reddit.com/r/Futurology/comments/34cq1b/the_facts_as_we_currently_know_them_about_the/

    “Every so often an article gets posted here about the state of these devices. These often end up being quite heated arguments between groups of people (on all sides) that are working with partial information, are conflating speculation with what we know, and that misunderstand what scientists are actually looking at.
    So, because this will continue to be a hot topic, and because Eagleworks will be conducting more experiments in full vacuums soon, I wanted to collect what information has actually been revealed, not what has been speculated in sensationalist articles, echo chambers, and comment sections.
    Let me be clear, although I described the news articles as sensationalist, the facts as we currently know them are ALSO quite sensational.

    EmDrive vs. Cannae Drive

    The EmDrive and the Cannae Drive are two different things. They were independently invented by two people. The EmDrive was invented by Roger J. Shawyer, a British aerospace engineer who has a background in defense work as well as experience as a consultant on the Galileo project (a European version of the GPS system).
    The Cannae Drive was invented by Guido P. Fetta and was formerly known as the Q-Drive.
    They both are claimed to use a specially shaped cavity, with constricted openings, cone shaped cavity in metal, closed at both ends, and operate by using some form of electromagnetic radiation in the microwave spectrum to generate a directional force. The EmDrive is claimed to receive its force from the shape of the cavity, while the Cannae drive was claimed to receive its force from the shape of the cavity, and from specially shaped “slots” on the inside of the cavity.
    The EmDrive has been tested in a laboratory twice independently (once by a team at the China Northwestern Polytechnical University (NWPU) in Xi’an, and once by Eagleworks at the Johnson Space Center), under different conditions and setups, while the Cannae Drive has only been independently tested once by Eagleworks.
    Although they are independently invented, and different in shape, and the inventors claim different effects are the cause of the resulting force, because of their similarities in concept and mode of operation, as well as the particular method of interacting with the microwaves, it is likely that if they work they operate on the same principle regardless of what the inventors claim.

    The Inventors Claims

    Both inventors claim that their devices do not actually violate any physics, and instead take advantage of very particular but speculative aspects of existing physics. It is important to note that while both theories are being tested, Eagleworks is testing whether or not the devices work as a SEPARATE thing from why they work.
    Shawyer claims that the EmDrive works only on radiation pressure. Light is both wave-like and particle-like. Though it has no mass, it does have momentum, and the fact that light exerts a very small force on the objects it interacts with is well documented.
    Shawyer claims that the pressure exerted by light is a result of the group velocity of the wave, not the singular velocity of the the photon that interacts. He then uses this to contend that radiation pressure is actually a Lorentz force. As scientists understand it now, the momentum of a photon is related to phase velocity, while group velocity measures the propagation of information.
    Fetta contends that the Cannae Drive creates a bias in the quantum vacuum and pushes against it. Basically, physicists think that at very, very small scales, much smaller than atoms or even protons, space bubbles with quantum fluctuations. This bubbling is represented in the math as sort of imaginary particles that are spawned in pairs, and then very, very quickly the pairs come back together and destroy each other. Fetta contends that the Cannae Drive creates a bias where some of these particles never come back together, and then “pushes” against them.

    Cannae Tests So Far

    The only independent (not conducted by the inventor, the inventor’s company, or by labs hired by the inventor) tests of the Cannae Drive that I can verify have been done by Eagleworks at the Johnson Space Center.
    1. They performed three tests:
    2. The device as the inventor designed it.
    3. The device as the inventor designed it without the slotting that the inventor claimed was critical. (Called the “null test”.)
    A control test that used the same energy, but without the cavity present in the design.
    The results of these tests were as follows:
    1. Approximately 25 micronewtons of thrust at 50 Watts.
    2. The same results as test #1, showing that at the very least, the slotting provided no benefit or detriment to the effect happening.
    3. No measurable thrust.
    For each of these tests they use a torsion pendulum which could measure thrust down to about 10 micronewtons or so. They also ran the test multiple times. In addition, they ran the test in two directions, making sure that the directional thrust changed with the direction of the device (to attempt to eliminate the possibility of noise or instrumentation error). The Cannae Drive passed these test, and the control test showed it was unlikely (although not impossible) to be a heating or air current effect.
    The confusion over the naming of the “null test” however led many people to think that NASA reported the same thrust in the control test. This was not the case. The fact that the null test showed only that the inventor’s ideas for why thrust was being measured were incomplete or wrong, but it is certain that thrust was measured. That still does not eliminate other factors in measurement or the test setup that might have accounted for the measured thrust, although the control test does make the list smaller.
    The “null test” also was only performed on the Cannae Drive, and has no bearing on the EmDrive tests, as the EmDrive has no such features which might have be tested in this way, which has been another point of confusion among many people.

    EmDrive Tests

    The following independent tests have been performed for the EmDrive.
    1. A test at 2500 W of power during which a thrust of 750 millinewtons was measured by a Chinese team at the Chinese Northwestern Polytechnical University.
    2. A test at 50 W of power during which a thrust of 50 micronewtons was measured by Eagleworks at the Johnson Space Center at ~760 Torr of pressure. (Summer 2014)
    3. A test at 50 W of power during which a thrust of 50 micronewtons was measured by Eagleworks at the Johnson Space Center at ~5.0×10−6 torr or pressure. (Early 2015)
    4. A test at 50 W of power during which an interferometer (a modified Michelson device) was used to measure the stretching and compressing of spacetime within the device, which produced initial results that were consistent with an Alcubierre drive fluctuation.
    All these tests were conducted with a control device that did not produce thrust.

    UPDATED

    NOTE: a better source was found for the Chinese results, and I have changed this section to reflect that.
    Test #1 was conducted at the direction of lead researcher Juan Yang. She tested the device at several power levels and frequencies using the same equipment used to test Ion Drives. The given result above was the largest result produced. Her team estimated that the total measurement error was less than 12%. Source 1 | Source 2
    Tests number 2 and 3 were performed multiple times, changing direction of the device and observing a corresponding change in the direction of force. They were not especially careful about controlling for ALL variables however, mostly owing to the lack of funding for the project. The positive tests have resulted in more funding becoming available, although it is still very, very little, and possibly not enough to explain where the error occurred if the measurement is error of some kind.
    Test #4 was performed, essentially, on a whim by the research team as they were bouncing ideas off each other, and was entirely unexpected. They are extremely hesitant to draw any conclusions based on test #4, although they certainly found it interesting.
    The Eagleworks team has been able to dedicate very little hardware towards this experiment, as there has been almost no dedicated funding for this experiment. The lack of funding is related to how outlandish the claims are to those who understand physics very well, and the lack of adequate explanation on the math behind the devices from the inventors.

    Criticism

    Much criticism has been given to the experiments. Some of it is warranted, but some of it is confusion.
    The idea that the control produced thrust is false, and has been perpetuated due to people interpreting the name “null test” to correspond to the control test. Other physicists have attacked the results based on the null test as well, although they have limited the criticism mainly to showing that the explanations provided by the inventor are wrong, not to invalidate the data collected so far.
    There has also been much criticism over not testing in a vacuum, (although they have since tested the device at approximately 5.0×10-6 torr pressure and achieved identical results), while others have claimed the team did not account for the Earth’s magnetic field.
    I can’t find any definitive accounts that the team accounted for Earth’s magnetic field, but many find it hard to believe that they would be putting so much effort into these tests without accounting for something that is so easy to account for.
    Others have criticized the measurement devices, specifically that so little force was measured. While the measured thrust was over 5 times the sensitivity limits of the torsion pendulum, with such small forces it is much easier for some sort of noise or other factor to appear to be thrust.
    Relatedly, some have claimed that tests at such small power are useless. The main reason the tests were conducted at such low wattage have to do with the hardware that was available to test with, and Eagleworks is planning on conducting a higher power test sometime this year.
    Some have questioned why no companies such as Boeing, Lockheed Martin, or SpaceX have attempted to investigate the device, but regardless of how likely these companies find the results so far, the largest reason is almost surely that the devices are both patented by their inventors.
    Most however have criticized the tests based on the fact that there is no explanation for such results, and that they apparently contradict known laws of physics. With no understanding of the mechanism of such a device, the obvious answers seem to violate principles that nearly every other experiment in history have followed. For some, this alone is enough to dismiss the data, regardless of the controls used and the directional results.

    What’s Next

    Following the positive results last year and early this year, Eagleworks have been able to dedicate more and better hardware to the experiment. They plan to conduct the experiment with more controls at higher power this year, and when they are able to achieve results higher than 100 micronewtons for either device, they plan on having the test replicated at the Glenn Research Center, the Jet Propulsion Lab, and John Hopkins University Applied Physics Lab.
    If the experiment for either or both devices is replicated at higher power, and again at the other labs, it is likely that the physics community will work very hard to try and invalidate the experiments as there is little explanation for the results. This is good. This is science. You don’t do science by proving correct things, you do science by disproving wrong things.
    If either device gets to that stage however, it is likely that someone will start on a test in space very quickly. The applications for a device that functions as these appear to would basically replace every form of transportation and thrust invented by humans to date. Such a device would easily be used to make cars, planes, bikes, boats, etc., all more efficient, clean, and cheap.
    There are many reasons to doubt we will ever be flying to Saturn with one of these things, but it is equally important to talk about science in the context of what we KNOW.
    We KNOW that this experiment is producing results that contradict hundreds of years of other data, although that data was collected under different circumstances with different characteristics.
    We KNOW that thrust is being measured, and that it is beyond the range of “noise”, and that it is directional according to the device, but we do not know if the cause is thrust actually being generated, or some other factor which makes it appear that way.
    We KNOW that Fetta’s explanation for the Cannae Drive did not pass the “null test”, making it extremely unlikely that his explanation is correct. We also KNOW that Shawyer’s explanation for the EmDrive involve physics that won’t actually be directly tested with this device, and so even a positive result doesn’t necessarily vindicate his explanation.
    We KNOW that it’s very likely that the results are spurious, and that is why we are dedicating so few resources to the tests that the team didn’t even have vacuum rated capacitors for over six months. But we also KNOW that a positive result, however unlikely, would be a world changing discovery, and so the possible reward is great, while the extremely limited resources we are committing to the project give us little risk.
    And finally, we KNOW that the teams involved at the moment are well educated, well trained, experienced researchers dedicated to figuring out what is true, not what people wish was true, and so we should have little reason to criticize the researchers personally for their involvement in such a project.
    All of the stuff we know has come out without any results being published, because all the researchers involved, in the US and in China, are committed to doing a thorough job before drawing final conclusions. When you get a peek behind the curtain, science looks incredibly messy, but the result is a better understanding of our Universe, and that’s always worth it no matter how these tests pan out.”

    1. If they claim that it operates using known laws of physics, and violates conservation of momentum, publishing a peer reviewed paper that shows how this is possible would be a great way to receive support and funding. I’ve yet to see any explanation beyond hand waving and making up imaginary things with that involve a misuse of the word plasma.

      1. “4. A test at 50 W of power during which an interferometer (a modified Michelson device) was used to measure the stretching and compressing of spacetime within the device, which produced initial results that were consistent with an Alcubierre drive fluctuation.”

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