The QDrive: a "radiation pressure imbalance" drive for space travel

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80 Responses to “The QDrive: a "radiation pressure imbalance" drive for space travel”

  1. iamlegion says:

    So… it’s like a solar sail, without the ‘solar’?

  2. angrydroid says:

    The term “resonating cavity” just makes me giggle a little bit.

  3. yri says:

    Will these hubcaps improve the mileage on my ’89 Festiva?

  4. kattw says:

    It SOUNDS like a version of what I saw in college, almost…  They took, essentially, a flying metal cone, and shot a laser under it to superheat the air.  This kind of tech is clearly different, since that was just utilizing hot air, but still.

    Maybe it’s like those little spinning gizmos in the vacuum bottles?  They look a bit like weathervanes, with each pole being black on one side and white on the other, and you shine a light on them and they spin.  Something like that could, theoretically, propel something through space, where there should be relatively few other forces.  Around here on earth though?  Probably too much gravity to get much done.

    Of course, I could be crazy, and read the web, and see what it REALLY does…

  5. Chuck says:

    Finally!  I was getting sick of those radiation burns from using my Norelco shaver.

  6. dustbuster7000 says:

    I’m going to go with ARG promotion for some new TV show until I get a chance to look over their site… 

  7. RadioSilence says:

    It’s a… space ash tray?

  8. Max Kaehn says:

    “Currently accepted physics states that creation of an unbalanced force is impossible. The QDrive is a device that generates an unbalanced force.” Keep a big bag of rock salt on hand for taking this with.

    • Daniel Tose says:

      I think that’s mostly using the wrong term. In one of the other videos he says the device must be powered at a specific frequency so he isn’t actually trying to claim the device is unpowered when he says it’s unpowered. Alternatively, he’s flat out pants on fire lying when he says that it’s fuel-less. 

      So once we’ve determined that it must be powered, we need to determine if the thrust per kg of fuel is better than what is currently available. Since they don’t directly answer this, the answer is pretty much certainly no. If they are trying to rely on solar panels to get the power, they run into the issue of more effective ways to redirect the energy of sunlight. 

      General rule about claimed new technology. If a company is talking about both inventing something thought to be impossible and making millions off of applications of that technology, it’s fake. They are looking to rip off investors.

    • John Oehler says:

      Nope, Ion drives have reaction mass, namely Ions. :)

      It sure seems like a new type of EmDrive, which has been criticized and would have been reproducible by now. 

      Although I do find reactionless drives fascinating, I think we would be leaving normal spacetime at that point.

  9. angusm says:

    Is this any relation of the EmDrive? http://en.wikipedia.org/wiki/EmDrive

    And, if so, what happened to N, O and P?

  10. moosestudiospottery says:

    I Call BS-  its a “reactionless drive”  which violates a number of laws of physics, Ill just put this right next to the perpetual Motion motor and the unbalanced wheel……

    it is pretty though

  11. pfooti says:

    I think it’s pretty straightforward. If this “imbalanced force” (time-averaged or otherwise) can actually cause a directional push over time (and not, say push in random directions averaging out to nothing), then it’s doing work. If it’s doing work, it’s using energy. Propellant or no, you pretty much get work from energy, and you don’t get energy from nothing.

    With all the equations and whatnot, there’s always a chance I’m overlooking something. But if that’s the case, then they should be able to put that there doohickey on the ground and watch it levitate.

  12. Jim Nelson says:

    They’re talking about generating 14 mN of force with a 10 watt pulse in the proof of concept. For an efficiency rating of around 0.15%. And that’s with their numbers…

  13. GeorgeStanton says:

    I’m not sure what the point of this device is. If it’s using some externally generated photons, then it sounds like a glorified solar sail. If it’s generating the photons internally and then spewing them out the back, then it sounds like it’s the same as every other rocket except emitting electromagnetic waves instead of some kind of particle. Maybe it’s more efficient somehow?

    That bit about “creation of an unbalanced force is impossible” is completely wrong. If it were not possible to create imbalanced forces then nothing could move.  (Momentum is conserved, not force.)

    Given how inaccurate that one statement is, I wouldn’t trust the rest of their explanation either.

    • ackpht says:

      Forces sum to zero. Newton’s third law.

      Acceleration is indeed possible without propellant. You can be under the influence of gravity, for example. Or there can be a force applied to you due to radiation pressure from the sun. But a force has to come from somewhere, or there’s no acceleration (Newton’s first law).

      Wading through the physics jargon, it sounds to me like this device purports to provide a net acceleration force by virtue of local imbalances in an oscillating EM field- no matter ejected, no interaction with external E or M fields. Bogus. As if the jargon didn’t give it away.  

      • John Oehler says:

        Right on. Now all we need to do is truly understand spacetime, gravity, and be able to generate huge amounts of energy required to bend it around – and we could have reactionless drives. Of course at that point we would also know how to time travel and bend space so that such drives would immediately be obsolete. 

  14. darue keller says:

    this is just a rip off of the emdrive, which may be real. This however looks like sucker-bait for an investment fraud.

  15. ADM says:

    Since I don’t know anything about physics, I’ll just go with the ad hominem argument instead.

    Googling the inventor’s name is not confidence-inducing. There are not many references to him on the web, but the substantives ones are related to (1) His wife’s retreat for people traumatized by abortions, and (2) Homeopathic remedies related to fiber intake. His food company — CNI — is onomastically similar to his space propulsion company, Cannae. (It’s also called Colloides Naturels.)

    But, I wish him the best of luck with his invention, which is filed with WIPO:

    http://www.wipo.int/pctdb/en/ia.jsp?ia=US2006/035265

  16. darue keller says:

    GUIDO FETTA? please. somebodies running a scam and it’s NOT FUNNY.

  17. Jim Nelson says:

    What it looks like they’re doing is using RF energy to create a magnetic field in the “QDrive” and then use that same RF pulse to impart motion due to its interaction with that induced magnetic field. Interesting, if it can be independently verified. But the documentation is kind of wonky and not well written, and I’d call myself at the level of a pretty fair amateur physicist. I have my doubts…

  18. stuck411 says:

    My question is how long would it take the engine to pop a bag of popcorn? Those long distance flights make me hungry.

  19. darue keller says:

    note the media “leaders” supposed name – JOEL HODGSON

    Invention exchange time? we’ve got commercial sign in 3… 2… 1…

  20. geekcalif says:

    Unless it  emits a spooky, green-ish glow like in all those Stephen King movies, it ain’t worth the titanium alloy it’s made of.

  21. eth0 says:

    I needed a new hair-trap for the Bath, this’ll look Q-uite nice

  22. dustbuster7000 says:

    Searching for some of the jargon in the Cannae website pulls up some pages that are identical to the Cannae website but fall under the SiteCats URL.  The Cannae website specifically lists SiteCats as their web developers, so this might not be anything.  Also SiteCats state that they are in the same town as listings for Guido Fetta.

    But a lot of the stuff on the site is plausible, but a bit odd.  What is equatorial symmetry for example? Do they mean rotational symmetry?

    I’ve found physics paper as that reference resonating cavities using masers, but they are super conducting, made of exotic materials and not related to propulsion.  More work needed…

  23. darue keller says:

    Look into the reality this seems to be spoofing… the emdrive… which has been developing for many years…
    http://emdrive.com/
    http://emdrive.com/principle.html

    • ADM says:

      If you look at the WIPO patent documents from my previous comment, you will see that it appears to be the SAME as the emdrive — just with a new name. There’s even a reference to the “Q” segment of the emdrive in the documents, which date back to 2005 or so. (The “EM” in emdrive, btw, is for electromagnetic, apparently.)

      There’s also some great lines buried in the documents, like this one: “The inventor is uncertain how the unidirectional thrust generated…comports with conservation of momentum.”

      • darue keller says:

        not the same, it’s very different in shape, and the qdrive text doesn’t mention ‘group velocity’ or wave guides. but sure seems to borrow and reconfigure a lot of half-baked jargon. Which in the case of the emdrive, isn’t jargon, but actual descriptions of how it works. (btw, things do seem to be happening with the emdrive, and China has become interested in it as well.)

        • ADM says:

          Interesting. The patent documents do mention the Emdrive repeatedly by name — but it’s unclear whether he’s calling the device “Emdrive” or just saying, the Emdrive is an example of such a device. I wonder who wrote all the text in the patent application.

          BUT it looks like we don’t need to pick it apart too much: amazingly, the folks at WIPO evaluated all the documentation themselves and issued a verdict in March 2008:

          “The claimed systems…allegedly operate in a manner clearly contrary to well-established physical laws and thus the invention cannot be carried out.” They cite Encyclopedia Brittanica and the conservation of momentum.

          See page 4 and 5: http://www.wipo.int/patentscope/search/docservicepdf_pct/id00000006155563

  24. dustbuster7000 says:

    Nope never mind, equatorial symmetry is something else.  Like I said, more work needed (mine).

  25. Mac says:

    From a quick look it appears to be the same as the EmDrive.

    The experimental results are particularly poor.  They have a device in a liquid helium bath and bring it up to atmospheric pressure.  Then they pump 10.5 Watts of power into it (for an unknown time – so the energy of the pulse is unknown) which provides the most minute stresses in the device – equivalent to 8-10 mN?  

    The result exactly matches conventional theory – that pumping energy into a device cooled by liquid helium will cause  tiny thermal stresses that can be picked up by load cells.  Worst still – the bumps that we are meant to be impressed with are only about half a millivolt – when it drifts by a couple of millivolts over the experiment.   

    The good thing about the setup is that they can run tests over and over  and over again to get plenty of data try to help eliminate these kinds of concerns.   They can do an identical run with a while blocking the EM wave (but generating things normally apart from that) and compare the data.  They can run the experiment at a different angle to see if the change in force changes with expectations.  They can run the experiment with different H field strengths to see if the  force is linear with field strength or fairly arbitrary.

    And yet, despite this, they don’t present a single one of the these results.

    Instead – they only provide a single ambiguous graph from a single run.  That is exactly what you would do if you were cherry-picking ambiguous data to pick the one where thermal stress could be interpreted as a consistent force. 

  26. Jim Nelson says:

    The one big problem I have with it is that it’ll need a whacking big RF source to operate. At a huge inefficiency. 10W is not that big here on earth, but it’s a pretty stout amount of juice to beam to a satellite.

    Let’s assume a 10x increase in efficiency and be charitable. It takes 10 newtons to counteract gravity on 1 kilogram. Back of the napkin calculations tell me they’ll need to dump something like 715 watts into it to counteract the forces of gravity on 1 kilogram, assuming a 10x efficiency increase. Extrapolating that to a 500 kilogram package (say, a small space experiment) says you would need a 350 KW RF pulse to drive it.

    As it is, it would require a 7 Kilowatt RF pulse AT THE DRIVE UNIT ITSELF to merely counteract gravity, and lift 1 kilogram. And that’s assuming:

    1. This isn’t completely bogus.
    2. There isn’t some other kind of force operating on the experimental apparatus.
    3. This effect does not change under more powerful RF fields.

  27. It’s certainly possible — photons may be massless, but they do have momentum and therefore a stream of photons can and does exert force. That’s how a solar sail works. However, the amount of energy you have to expend per unit of force is breathtaking — enough to that the amount of mass you have to turn into energy in order to power it becomes significant. At the end of the day, it’s just a rocket with an exhaust velocity equal to the speed of light.

  28. ispivey says:

    The world can’t have enough phallic logos.

  29. Happler says:

    Please see the turbo encabulator:

    http://www.youtube.com/watch?v=rLDgQg6bq7o

  30. echolocate chocolate says:

    I’ll leave it up to the real scientists to talk about why or why not this is a legit device–but the combination of (1) attractive, expensive graphic design, and (2) mention of the laws of thermodynamics, in the context of “why this device does not violate them”, suggests VERY NOT.

    The branding IS very nice though. Nothing fake about that.

    I bet you real vendors of aerospace propulsion devices have absolutely atrocious branding.

  31. Jim Nelson says:

    Just for a laugh, I carried this forward. To get up to escape velocity and out of Earth’s gravity well, 1 kilogram would need 37 newtons of force per second for 5 minutes, in addition to counteracting gravity.

    That would require a pulse of 3200W. Per kilogram. For 5 minutes. While it’s accelerating away from you.

    Even more fun is getting it going fast enough to head towards the outer solar system. That requires a 10.7 KW pulse for that same 5 minutes. a 500 Kilogram package would need 5 megawatts (at the same theoretical 10x efficiency improvement) for that same 5 minutes  to launch. Delicate electronics don’t like that kind of RF field…

    Of course, IANAOME (I am not an orbital mechanics expert) and I may have my math off. But it’s enough for a basic extrapolation – unless they can prove the effect happens with multiple KW of energy getting dumped into the thing, it just won’t work for launching objects into orbit. And there are better low-energy drives out there that are being proven to work right now.

  32. V says:

    I’m going to put it on the shelf over here right next to my 100 mpg carburetor….

  33. taintofevil says:

    “draw your own conclusions” seems like a bit of a giveaway.  I don’t think actual physicists use that phrase very much.

  34. Bobby Martin says:

    I am not a physicist, but I do have a BS in Physics.  (And that’s not some unsubtle way of saying I’m BSing you ;-) )

    Either:
     a) they’re claiming that a closed chamber from which nothing escapes is imparting momentum to the chamber, hence violating conservation of momentum, hence their claim is total bullshit
     b) they’re claiming that they have some fancy thing that emits something in one direction and moves in another direction, which is boring without some nice efficiency numbers

    Either way, it wasn’t worth the time any one of us spent thinking about it, much less the cumulative time spent.

  35. Grant Bugher says:

    So, this doesn’t violate conservation of energy — the drive requires energy to operate and converts that energy to thrust, and quite inefficiently.  However, if it worked — and that’s a *huge* if — it would be revolutionary for long-distance space travel.

    Some people have pointed out that it would be worthless for launching something into orbit — yes, it would be.  But we can already do that with conventional technology.  This thing purports to produce a small amount of thrust without spewing anything out the back — and for long-distance space travel the lack of propellant is an enormous benefit.

    If I want to get from here to Alpha Centauri, 4 light years away, at half the speed of light and a 3,000-pound payload, we will have to carry an amount of fuel that exceeds the mass of the observable universe!  Even an ion drive would need a propellant tank the size of several hundred supertankers.  Carrying a nuclear reactor to power this reactionless drive would be a lot more practical than carrying several planets of propellant to spew out the back.  This thing is designed for propulsion in hard vacuum outside a gravity well, not for launching into orbit.

    But then… that’s if it works.  Unbalanced forces violate conservation of momentum and require a new physics.  I’ll believe it when they demonstrate it in space and not in a lab where there’s plenty of crap around for electromagnetic forces to interact with and throw off their measurements.

  36. Peter Park Nelson says:

    Yeah… Joel Hodgson… I’m not the first to notice that but hah!

  37. dculberson says:

    “And draw your own conclusions.”

    Annnd that’s all I needed to know it was a scam or a joke.

  38. dross1260 says:

    Wait. You can find these leaning next to any mailbox.

  39. NelC says:

    I recall that there was an article in New Scientist a few years ago describing a conservation of momentum-violating device in very similar terms. Was that the emdrive that other people are mentioning? Anyhow, I recall that several blogs I read at the time got absolutely disgusted with NS for publishing such a lot of woo. If this is a real thing, then I suspect it’s probably wonky physics that isn’t going to lead anywhere.

    Edit: I think this is the article.

  40. p96 says:

    Hogwash! It be for crispin’ yer pizza crust.

  41. technogeekagain says:

    Extraordinary claims require extraordinary proof.

    Pretty metal, pretty logo…. pretty obviously bogus.

  42. pjcamp says:

    Physicist here.

    Yes, this is bullshit. It is essentially a variation on the EmDrive, which Wikipedia has a minimal article on.

    The trouble is that conservation of momentum is a direct consequence of translational invariance of the Lagrangian (via Noether’s Theorem), which the Lagrangian of the electromagnetic field satisfies. So no electromagnetic phenomena can possibly generate non-zero total momentum in the entire system of interacting objects if they started with zero total momentum. Translational invariance is so deeply embedded in the structure of electromagnetic theory that it is pretty well inconceivable that it would be violated. It is an essential property of Maxwell’s equations, as well as quantum electrodynamics and the electroweak unified field theory. Without it, about 200 years of physical theory and experiment falls apart.

    It also violates the principle of relativity since it would require the total energy of the universe to be a frame dependent quantity. In fact, energy could only be conserved in at most one reference frame since in any other frame the kinetic energy of the ship would differ from the energy expended by the ship.

    This is also an idea deeply embedded in centuries of physics theory and experiment. Conservation of energy is a consequence of time invariance of the Lagrangian (Noether again), which the electromagnetic Lagrangian does satisfy. If it did not, Maxwell’s equations would vary in form over time.

    And am I the only one who thinks that Q is excessively excited?

    • Hey PJ, you forgot the bit where photons have momentum. Therefore, it doesn’t violate conservation of momentum or relativity. It is, however, utterly impractical. 

      • pjcamp says:

        No, I didn’t. Photons are quanta of the electromagnetic field. So when I talk about the EM field conserving momentum, that includes photons.

        Conserving momentum doesn’t mean simply “everything has momentum.” What is means is that the total momentum of a system of interacting particles never changes. And momentum is a vector quantity. So if something acquires momentum in one direction, something else must have acquired momentum in the opposite direction. That isn’t happening here (in fact, its sort of the point) so this thing violates a major tenet of physics that underlies very nearly everything we understand about the world. In over 300 years, not one single violation of momentum conservation has ever been observed.

        • There is a professor at Cal. State working on similar device. The reasoning behind the momentum (conservation) is that it is indeed conserved, if one takes the whole universe into account, i.e. the rest of the universe is moving (infinitesimally) in the opposite direction. The name of the propulsion system is Mach Effect Propulsion.

          • pjcamp says:

            Interesting idea. I doubt it will work, but I’d be happy to be proved wrong. Mach’s principle (that inertial mass is determined entirely by interactions with the rest of the universe) was something Einstein tried to incorporate into General Relativity but it just wouldn’t fit. That suggests to me that Mach’s principle is probably wrong, though it doesn’t prove anything. Our current understanding of the origin of inertial mass is through the Higgs boson, which has nothing to do with Mach’s Principle.

  43. kP says:

    A Steorn by any other name….

  44. ndarnton says:

    Another physicist calling BS on this.

    Whether it’s called the EM-drive or something else, this device unquestionably violates conservation of momentum.  The spontaneous acceleration of a *closed* device is not consistent with physics as it is currently understood.  If you emit something out the “tailpipe” (be it ions or electromagnetic radiation) that’s another story, but no closed system can change its own momentum simply by interacting with itself.  I should confess that there are non-standard (read: highly speculative with no evidence that they correspond to reality) mechanisms for this type of phenomenon.  However, I believe that this device is supposed to have been designed (and analyzed) according to the normal laws of physics: if so, it cannot work as claimed because it would violate conservation of momentum (and probably relativity), which are built into all standard laws of physics.I use the EM-drive as an example of a violation of Newton’s third law (the action-reaction one) in my intro physics class.  They can make the design complicated enough that no reputable physicist is willing to wade through the analysis to find their errors, but that doesn’t mean there isn’t an error in there somewhere.  That’s the beauty of a conservation law: I don’t need to examine every detail to know that momentum cannot be created out of nothing. 

  45. It’s called the Reverse Casimir Effect. Yeah, it’s real. Google it.

    • pjcamp says:

      Reverse Casimir effect is real but has nothing to do with this device. What they describe is a resonant cavity much like the EmDrive.

      Even if that were not the case, it still wouldn’t work. Various Casimir-dependent devices have been proposed over the years. They don’t work.

      The Casimir effect is a weird byproduct of quantum field theory due to the face that the vacuum is simply the ground state of a field and, while it is the lowest possible energy of the field, it is not zero energy. That would violate the uncertainty principle. Furthermore, also because of the uncertainty principle, virtual particles emerge from and then vanish again into the vacuum all the time. They are called virtual because they don’t exist long enough to be observed. Again, that would violate the uncertainty principle.

      So you create a Casimir force by creating boundary conditions for the vacuum. For example, you can put two plane mirrors facing each other. Since the electric field must go to zero on a reflective boundary, this reduces the number of allowed vacuum fluctuation states between the mirrors compared to the unbounded area outside. That in turn creates a tiny force pushing the mirrors together. Some clever guys in Scotland think they have come up with a way to jigger the process so that you can push things apart as well as together.

      There are two problems with trying to use this for propulsion.

      First, the force is truly tiny. It is proportional to Planck’s constant, which is small to begin with, and inversely proportional to the fourth power of the plate separation, which means it diminishes rapidly with distance between the mirrors. That makes it far too small to use for propulsion over anything greater than nano distances.

      Second, momentum is still conserved. Whether reverse or not, each mirror experiences an equal force in opposite directions all the time. That means that it is not functionally different from a regular rocket. You use some sort of force to throw mass out the back, therefore throwing yourself forward. The total momentum of the system is still zero.

  46. HenryPootel says:

    It’s either modeled after one of those “Sex in a CAT Scanner” images, or Beavis.

  47. An Infinitude of Tortoises says:

    Destined, no doubt, to take its place alongside the Dean Drive.

  48. the lurch says:

    I call bullshit.  I’m not a physicist, but you don’t need to be.  Guido Fetta?  The man is a marketing guru (20 years experience!) , not an “inventor”.  His presentation was carefully crafted to sound authentic but he provides no real facts.  Unbalanced force?  Yep. Cash flows from the wallets of investors, with no net result.   Where do these people (and the gullible dopes that follow them) come from anyway?

  49. Cowicide says:

    It runs on Chaos Magic.

  50. Stefan Jones says:

    Wait . . .  they’re not claiming that Big Rocket is out to suppress their invention to ensure their monopoly on space travel?

  51. moosestudiospottery says:

    here is a consice explanation of how it works (spoof)

    http://www.youtube.com/watch?v=SjxfAjAyp5k

  52. 3William56 says:

    Isn’t it obvious? The Interossiter’s Dilithium Flux Capacitor clearly interacts with a resonance cascade in the  bloater drive warp core to distort a subspace anomaly quantum flux via a net imbalance of 1 point 21 jigawatts  in the etherical phlogiston density surrounding the epicycles resulting in… PROFIT!

    Shame on those questioning the physics here. I believe this is already established as the practical power source of the beloved Nyan Cat.

    Q is for Quack.

  53. Guest says:

    Very cool!  The limiting factor would be providing energy to the system, and making sure you don’t lose your helium to fast.  Seems legit.

  54. garyg2 says:

    So it won’t make the Kessel Run in less than twelve parsecs?

  55. Peter Hill says:

    I’m not sure if anyone has posted the actual reason why this is wrong, but the creators have basically missed a term. From their “Principles of Operation” section:

    “In linear-accelerator applications, the EM electric-field energy is used to accelerate charged particles. After accelerating a charged particle (and increasing the charged particle’s momentum), the EM wave retains a zero net momentum”

    This is wrong. The electromagnetic field has a momentum of its own (proportional to its energy). In accelerating the particle, the field has done work – so its energy must decrease, which means that its momentum must also decrease. The only way the field could retain zero  net momentum is if it also accelerates a particle in the opposite direction. Side-note: “EM electric-field energy” is a very strange thing to say.

    In their device, even if the wave imparts some momentum to the cavity walls, it will be *exactly* balanced by the loss of momentum from the wave itself.  They don’t give the right numbers or anything usual enough to actually check any of their calculations.

  56. serpent says:

    Anyone else noticed the dark, deep, low key humming during the videos?

  57. tolkes says:

    There is something very phallic about their logo

  58. These things show up every few years. For example, in the 1950s there was the
    http://en.wikipedia.org/wiki/Dean_Drive

    Dean Drive, which supposedly provided momentary unidirectional force. If was even demonstrated on the popular TV show “I’ve Got a Secret”, where the inventor placed the device on a common bathroom scale, and as we watched the gadget would momentarily register less weight. It was highly promoted by John C. Campbell, the editor of Astounding/Analog  SF Magazine, the man who also introduced the world to Scientology.

    The video listed here shows the bathroom scale trick.
    http://www.youtube.com/watch?v=mtBvzCjpPcE
    it seems obvious that what is really happening is that when the gadget generates is sudden shifts of momentum it is overwealming the scale’s ability to register.

  59. Richard says:

    also doubles as a birth control pill holder

  60. Halloween_Jack says:

    I suspect that the real purpose of this device is to create a career for the “inventor” on the woo lecture circuit, where he’ll entertain an audience of fellow cranks and slack-jawed fans of second-rate science fiction with his tales of how he almost invented warp drive, but The Man kept him down. 

  61. Daniel says:

    They admit right on the site that it overturns really fundamental conservation laws but they decided to announce it with a really slick website instead of, you know, a peer reviewed physics paper or something?  I would think a physicist with new physics would be trying to get people to replicate xir results.

    It doesn’t look like the Woodward effect (on which  “mach effect propulsion” mentioned in the comment above is allegedly based) has been widely replicated or accepted either. 

  62. Mark Harrigan says:

    Cannae… as in “she cannae take it cap’n”?

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