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Marc Millis on Mach Effect Thruster, EmDrive Tests

Marc Millis spent the summer of 2017 at the Technische Universität Dresden, where he taught a class called Introduction to Interstellar Flight and Propulsion Physics, a course he would also teach at Purdue University last November. The former head of NASA’s Breakthrough Propulsion Physics project and founding architect of the Tau Zero Foundation, Marc participated in the SpaceDrive project run by Martin Tajmar in Dresden, an effort that has been in the news with its laboratory testing of two controversial propulsion concepts: The Mach Effect Thruster and the EmDrive. Marc’s review comments on modeling for the former were almost as long as Tajmar’s draft paper. Described below, the SpaceDrive project is a wider effort that includes more than these two areas — neither the EmD or MET thruster had reached active test phase during the summer he was there — but the ongoing work on both occupies Millis in the essay that follows.

by Marc Millis

You may have noticed a renewed burst of articles about the EmDrive. What prompted this round of coverage was an interim report, part of the progress on Martin Tajmar’s ‘SpaceDrive’ project to carefully test such claims. Tajmar’s conference paper [citation below] is one of the early steps to check for false-positives. I expect more papers to follow, each progressing to other possibilities. It might take a year or so more before irrefutable results are in. Until then, treat the press stories about certain conclusions as highly suspect.

On Tajmar’s work, this quote from his conference paper:

Within the SpaceDrive project [6], we are currently assessing the two most prominent thruster candidates that promise propellantless propulsion much better than photon rockets: The so-called EMDrive and the Mach-Effect thruster. In addition, we are performing complementary experiments that can provide additional insights into the thrusters under investigation or open up new concepts. In order to properly test the thruster candidates, we are constantly improving our thrust balance facility as well as checking for thruster-environment interactions that can lead to false thrust measurements.

The Mach Effect Thruster is a different approach to the goal of a non-rocket spacedrive, but one that is rooted in unsolved questions in physics where there is a chance for new discoveries. Its theory led to a testable prediction that then evolved into an idea for a propulsive effect.

The unsolved physics question is: “What is the origin of inertial frames?” One attempt to answer that is called “Mach’s Principle” (term coined by Einstein to describe Ernst Mach’s perspective), which is roughly: “inertia here, because of matter out there.” The idea is that the phenomenon of inertia is an interaction between that mass and all the surrounding mass in the universe (presumed gravitational in nature). Jim Woodward picked up on a version of this from Dennis Sciama, and noticed that the inertial mass of an object can fluctuate if its energy fluctuates (think energy in a capacitor). That led to an idea for a propulsive effect by varying the distance between two fluctuating inertias. Unlike the EmDrive, this idea has been in the peer-reviewed literature from the beginning, with some of the more relevant papers being:

Woodward, J. F. (1990). A New Experimental Approach to Mach’s Principle and Relativistic Gravitation, in Foundations of Physics Letters, 3(5): 497-506.

Woodward, J. F. (1991). Measurements of a Machian Transient Mass Fluctuation, in Foundations of Physics Letters, 4(5): 407-423.

Woodward, J (1994), “Method for Transiently Altering the Mass of an Object to Facilitate Their Transport or Change their Stationary Apparent Weights,” US Patent # 5,280,864.

Woodward, J. (2012). Making Starships and Stargates, Springer.

Fearn, H. & Wanser, K. (2014). Experimental Tests of the Mach Effect Thruster. Journal of Space Exploration, 3: 197-205.

Martin Tajmar’s laboratory results can be summarized this way: False positive thrusts were observed under conditions where there should be no thrusting or only minor thrusting. More systematic checks have to be made prior to testing the thrusters at their nominal and maximum operating parameters. The mismatch was more pronounced for the EmDrive than for the Mach Effect Thruster. In both cases it is premature to reach definitive conclusions since this is a work in progress. And if any thrusters do pass all those tests, then more tests will commence to figure out how the thrusters operate (varying conditions to see which affect the thrust levels).

In the case of the EmDrive, only 2 W of the more normal 60 W of power was made available to the thruster. Even at that low power level, thrusts of about 4 µN were observed, which is more than the 2.6 µN expected from the claims from Sonny White’s tests. The more revealing observations were that thrusts were observed when the EmDrive was not supposed to be thrusting. When the EmDrive was pointed to a non-thrusting direction, thrusts were still observed. When the power to the thruster was sent to an attenuator to further reduce the power to the thruster by a factor of 10,000, thrusting at the prior level was still observed.

These observations do not bode well for the EmDrive’s claims of real thrust, but it is too early to firmly dismiss the possibilities. One suspect for the false positive is the interaction with the current to the device and the Earth’s magnetic field, where a current of 2-amps in a few cm of wires can produce a thrust in the µN range. Further tests are planned after adding more magnetic shielding and operating over different power levels.

In the case of the Mach Effect Thruster – which by the way, none of the press articles mentioned – the findings were less pessimistic. Again there were thrusts measured in excess of what was expected for the low power levels (0.6 versus 0.02 µN). Unlike the EmDrive’s mismatch, no thrust was observed when the Mach Effect Thruster was pointed to a non thrusting direction. There was, however, a case where the thrust direction did not change when the thruster direction was flipped. The suspected causes to be further investigated include both magnetic and thermal (expansion) effects.

A word of advice: if you plan to look at Tajmar’s paper. When I tried my usual “rush read” through the paper by reading the abstract and scanning the figures, I misled myself. Read the full text that accompanies the figures to know what you are really looking at. It’s a short article.

Regarding some representative press articles, here is a quick assessment

(1) David Hambling, New Study Casts Doubt on the “Impossible” EmDrive, But this weird propulsion idea isn’t dead yet

This one goes into more detail than the other articles about what was actually done and not done and does link to its information sources. It does not mention the Mach Effect Thruster.

(2) Mike Wall, ‘Impossible’ EmDrive Space Thruster May Really Be Impossible

This one mentions the doubt, but leaves the door open just a bit. Although it does not mention the Mach Effect Thruster also under test, it does at least give a link to the core article and mentions where it came from.

(3) Ethan Siegel, The EmDrive, NASA’s ‘Impossible’ Space Engine, Really Is Impossible: Many tests have reported an ‘anomalous thrust’ where there should be none. A researcher has finally shown where everyone else has messed up

This article talks more about the old claims and expectations than what was really in the new paper. It does not mention the Mach Effect Thruster.

(4) Mike Wehner, NASA’s ‘impossible’ fuel-free engine is actually impossible

More short-hand opinion, and again, no mention of the Mach Effect Thruster.

The takeaway: Science does not proceed by proclamation. Despite what headlines may say, laboratory work is a matter of refining techniques and bringing precision to bear on prior claims. At the moment, evaluation of the EmDrive and Mach Effect thruster continues, with no guarantee that either of these effects may prove genuine, but let’s let the process play out.

The Tajmar paper is Tajmar et al., “The SpaceDrive Project – First Results on EMDrive and Mach-Effect Thrusters,” presented at the Space Propulsion 2018 conference in Seville, Spain (full text).


Comments on this entry are closed.

  • Ron S. June 18, 2018, 13:49

    After all these years I think the only thing we’ve seen positively demonstrated is the importance of the null hypothesis in Bayesian statistics. I’ve had my own frustrations explaining this to a few roomfuls of smart people with a variety of engineering and science degrees.

    • Thomas Hair June 18, 2018, 23:40

      Ron S.,
      I could not agree more with your observation. Even among those who should know better, there is still a desire to believe in a God of the gaps. Heck, I want to believe as well in some super space drive, but the Universe has been able to create 5 billion year old environments like we find our selves in long before the formation of our solar system. Life and intelligence are probably very very rare and extremely isolated, otherwise we would not exist since at 1% of the speed of light a 5 billion year old intelligence could have traversed the Galaxy hundreds of times…and our planet 700 million years ago with nothing but cyano-bacteria and an oxygen rich atmosphere would be an easy moral choice for a biological intelligence. But maybe they’re robots ;-}, though again, more silly sophistry of the type you rightly point out. The most reasonable answer to the Fermi Paradox is that we are probably alone and that there is no magic space drive.

      • Andrei June 24, 2018, 7:30

        Hello Thomas.
        We certainly have the same idea / hypothesis here for the solution to the Fermi paradox. Though I think life is fairly common, but held back by less benign conditions than here on Earth as well as developing more slowly and never getting to the stage or counterpart of a “Cambrian revolution”.

        I played around with the idea of possible alternative means for a genetic code last week. Instead of wrapping the DNA ladder into the known X or H-shaped cromosome, my genetic strange would fold into a ball when not active.
        And the use of enzymes and heligase/ligase/polymerase/primase replaced by trace metals as a triggering swith and direct use of proteins instead of going via RNA.
        (Trace metals are also used in our type of life and use metals like cobalt, chromium, copper, manganese, molybdenum, nickel, silver, vanadium etc and to us is a necessary part of nutrition and physiology.)
        To my own amazement, I came to the conclusion that this alternative and simpler system for a genetic code actually could work. Yes expected to find a detail that would make it impossible.
        It’s quite simpler in several ways than what life on Earth use, ans so it could get started more easily, but it would also be more stable.
        That’s bad news for the idea of finding advanced life elsewhere, more stable means less mutations, and so such life might never get past the microbiological stage.

        Now as for the main entry here, its good to see that they keep looking into the matter of these ‘massless drives’ if not for anything else than to debunk the weird claims that have been made.
        In my opinion the Mach Effect Thruster do show promise, there is after all a good hypothesis why it would work, and as noted it have been published as peer reviewed papers from the start. So I find it sad to note that only the fringe science idea of the EM drive continue to get this attention in the press.

  • Robert June 18, 2018, 14:04

    I doubt the issue will really be resolved until or unless some experiments get well beyond the micro-Newton level. I really wouldn’t trust a grand proclaimation of either device’s impossibility by any micro-Newton level experiment. Could always be bad engineering irregardless of the precision of the supposed tests, but it could end interest which would be tragic if the effects were real. Since large scale effects beyond what could possibly be ascribed to subtle effects are necessary anyway to make use of these devices, I wish those replicating the effects would get out of the micro-Newton level experiments and go for broke by scaling it up. I’m assume Cannea and Roger Shawyer are both working with larger scale effects.

  • Robert June 18, 2018, 14:21

    It also needs to be said that issues that come up or cast doubt in Tajmar’s work do not necessarily apply to all other replications or implementations of these effects. I say that because in controversial work sometimes critics latch on to negative results to falsely proclaim something is dead and all other positive results must be wrong.

  • Greg Matloff June 18, 2018, 14:34

    Dear Marc

    Excellent article! Let’s remain skeptical but open. It would be so nice if a shortcut to the stars actually exists.

    Regards, Greg

    • Robert June 19, 2018, 12:53

      I see no valid reason not to be more optimistic about Woodward’s work. It seems to me it’s been replicated enough and simply cannot now be pronounced dead at some micro-Newton level by any particular setup without calling into question that setup first. There is an over developed sense in general to feign more skepticism with new ideas. Broad and startling implications of a new idea do not make it any less likely to be true yet that’s what most people seem to think. It’s faulty logic.

      • Mike Lorrey August 20, 2018, 12:35

        Agreed, I’ve followed Woodward’s work for 20 years, and he and his team have always been paragons of scientific rigor and objectivity. They’ve had too much positive results, and intentionally run experiments to rule out sources of false signal and bias, for the Mach Effect to not be valid. Running an experiment at a very underpowered state seems to me like putting your finger on the scale, hoping the signal disappears into the noise of known false signals. How about building a higher power model for once? Put some money into the materials science to make much more rugged, higher K value dielectric materials that can handle the thermal and vibrational loads? Put a test article up on a Cubesat in LEO, changes in orbital trajectory that cannot be ascribed to solar wind, or ionospheric/thermospheric drag, or gravity assist, are results that skeptics and critics cannot deny.

  • Alex Tolley June 18, 2018, 14:36

    Can anyone put acceleration values for these devices in context of solar sails at 1 AU?

    • Robert June 19, 2018, 13:14

      The NAIC team numbers work out to about 0.38 m/s^2 assuming it gets to about 0.4c in about ten years then decelerates to ten years. The Planetary Society estimates the acceleration of a typical solar sail at about 0.001 m/s^2 at 1AU with the solar force about 8.5 micro-Newtons/m^2.

      • Alex Tolley June 19, 2018, 19:27

        I was asking about the numbers they can get now (uN for the test devices) with the test equipment. Speculative projections are not of any interest.

        Solar sails have accelerations in the 10^-6 to 10^-5 m/s^2 range, with far higher performance possible with lighter materials. The EMDrive with just the engine and without the needed power supply mass looks like it is in the same range, or less, assuming it even works. Compactness and easier deployment are the values it offers if that is the performance.

        • Robert June 20, 2018, 12:41

          “Speculative projections are not of any interest”. CD is chock full of scientifically based and informed ‘speculative projections’ and that’s what makes it interesting, at least to me.

          • Alex Tolley June 22, 2018, 9:32

            Let me clarify. The premises are:
            1. There is a real effect behind the EMDrive
            2. The measured thrust for the power used is reasonably accurate.
            3. The thrust is linearly related to the power.

            Even if one accepts for the moment that 1 & 2 are true, that does not mean 3 is true. Hence very speculative.

            For photon sails, the physics is established, and test sails have flown. We know that scaling will work, and that light intensity, whether from the sun or lasers, will influence the acceleration, as well as areal density. Therefore, we can speculate about large, laser-driven sails as they are grounded in known physics. This is most certainly not true of the EMDrive.

    • Mike Lorrey August 20, 2018, 12:41

      According to Eagleworks Lab at NASA, the EM Drive thrust is two to ten times greater than what you would see from a light drive (i.e. a laser propulsion shooting photons out the back), which is reasonably identical to a solar sail where the sun is the light source. Woodward and Eagleworks have seen similar but more solid performance from the Mach Effect thrusters, and given thrust effects of the EM Drive are most pronounced when the dielectric disk is installed in one end of the resonant cavity, the growing consensus is the EM Drive also operates by Mach Effect physics, but using microwave photons as the working mass (shifting momentum from end to end by changing frequency or photon density as the resonant cavity cross section changes) instead of the capacitors in the ME thruster.

  • Thomas Goodey June 18, 2018, 16:09

    I thought this forum was for exploration of possibilities for interstellar travel that are not directly contradictory to (supposedly) known physics.

    I by no means discount the possibility that physics will be completely set head-over-heels next year by some epoch-making new discovery, but I thought consideration of such a development would be outside the scope of Centauri Dreams.

    Anyway, if you are going to consider the “Mach Effect Thruster” and the “EmDrive” (bad sign, that: having a catchy name figured out already, before any proof) as possible candidates for ways to get to the stars, no doubt you should consider the venerable Dean Drive as well.

    But if you are going to embrace claimed fringe-science effects as possible means to go interstellar, I think you should certainly be considering the concept of deriving nuclear binding energy via cold fusion. There’s a lot more evidence for that phenomenon than for the above rather flimsy proposals, and moreover it is not actually contradictory to established physical law. It is intrinsically much more plausible – which doesn’t of itself mean that it is true.

    • Robert June 19, 2018, 13:26

      Woodward’s work is not fringe physics. It’s a new application or discovery of previously well known physics. And it’s not in contradiction to known physics as those studying it have repeatedly tried to explain. Labeling things new as fringe is a disservice to those doing the work and those testing it. This is a perfectly reasonable and balanced interest here in that it doesn’t show up often and is always measured and in context.

      • RAS June 19, 2018, 15:16

        I wish these two devices wouldn’t get lumped into together as too me the Mach Effect thruster is an entirely different ‘beast’ with a much better theoretical basis than the EM Drive. It doesn’t surprise me that it is the one that gets the NAIC funding.

    • Antonio June 20, 2018, 17:13

      I totally agree with Thomas Goodey. It’s embarrasing that these topics keep appearing here.

      • Robert June 21, 2018, 13:41

        It’s valid and current research. I find it embarrassing some folks want to censor the discussion if it. I could argue that various schemes for interstellar travel discussed here with enthusiasm are equally embarrassing because they have virtually zero chance of ever being built but it’s fruitful to discuss all scenarios with an open mind.

        • Antonio June 21, 2018, 17:12

          Seriously? Are you comparing technologies that aren’t yet built for lack of money and will but based on solid physics, like fusion or radiation pressure, with ideas that contradict well stablished physics and that whose theoretical “deduction” contained elementary mistakes?

          On open minds:

          “Suppose you are a chef, cooking soup for two hundred diners. You say to yourself ‘Well, I know if I put arsenic in this soup it’ll kill everyone. But hey! Gotta be open-minded!’ And you go ahead and add the deadly metalloid to the goats’ cheese crostini and float it atop the watercress and mint broth. Are you being open-minded or… just ignoring important information?”

          • Robert June 25, 2018, 14:03

            NASA NAIC research grants have been granted to explore the Mach Effect Thruster concept so I’m not being closed minded to note that with a little enthusiasm.

  • Geoffrey Hillend June 18, 2018, 17:29

    I don’t think there is any new physics that can be discovered with the Emdrive and Mach Effect Thruster. I agree physicists should test them anyway to eliminate them. Mach’s principle has been made completely obsolete by general relativity. P. 238-239 Cosmology, 2nd ed, Harrison.
    The laws of physics are the same for all observers so there are no preferred or privileged reference frames. “The nature and existence of space time is not dependent on the existence of matter.” p. 239, ibid. “There can be no inertia relative to space, but only an inetria of masses relative to one another. If, therefore, I have a mass at sufficient distance from all other masses in the universe, it’s inertia must fall to zero.” Quote by Einstein, P. 239, ibid. http://physics.muni.cz/~novotny/-CSMLG/(Harrison%20E.-Cosmology_%20The%20Science%20of%20the%20Universe-Cambridge%20University%20Press%20(2000)).pdf

  • Project Studio June 18, 2018, 18:54

    Isn’t “There can be no inertia relative to space, but only an inertia of masses relative to one another” really a modified form of the Mach principle? The ‘privileged reference frame’ would be that of an observer traveling at c, but of course that observer (were it possible) would not have the time to make any observation. Mach-Effect and EM Drive are attempts to exploit the empirical reality behind these thoughts and concepts. We’re bound to discover something, if only the limits of our conceptualization.

  • Charley June 18, 2018, 18:55

    “When the EmDrive was pointed to a non-thrusting direction, thrusts were still observed. When the power to the thruster was sent to an attenuator to further reduce the power to the thruster by a factor of 10,000, thrusting at the prior level was still observed. ”

    kind of says it all

    • Robert June 19, 2018, 13:45

      No, it says that setup didn’t work or had issue but it can’t negate other work going on. The problem is some people are too quick to latch onto seemingly negative results because they really want to. They may be right but we have to overcome our tendency to eagerly throw out new ideas too soon.

  • Andrew Palfreyman June 19, 2018, 1:06

    Any “propellantless drive” is a perpetual motion machine of the first kind. As such it is an impossibility.

    These microNewton- (and below) -level apparent thrust measurements are experimental artifacts. Most likely they are Lorentz forces from the Earth’s magnetic field.

    • Robert June 19, 2018, 13:40

      I think you need to read Woodward’s work to understand what’s being proposed before making broad charges like that. Momentum is conserved in Woodward’s theory so in a sense it’s not truly propellent-less. It’s just that you don’t have to locally carry the propellent. Both the momentum and the necessary energy are provided for in General Relativity.

      Also, just dismissing the experimental results is short sighted. In fact, some claimed results are a lot larger than micro-Newtons.

      • RAS June 19, 2018, 15:18

        As a general point if you’re going to comment on the Mach Effect thruster at least familiarise yourself on the theory behind it.

        • Robert June 20, 2018, 13:05

          As a specific point, I have.

          • RAS June 20, 2018, 15:13

            Sorry. I more meant the person you were responding to.

    • AlexT June 28, 2018, 5:19

      So , if we should conclude that laser (light) sails idea is impossible?

  • john c gilmore June 19, 2018, 4:08

    Why not send up one of the small cubesats into space and see what happens. They send mice up to see if they can breed in space and they weigh more than a cubesat emdrive.

  • Rob Flores June 19, 2018, 10:32

    Not surprised the EM-drive is being falsified[metal+electricity =Not trivial interference]

    To test a Mach Effect thruster even if placed
    into deep space, is there not a galactic
    magnetic field out there? that would affect these testing results.
    Considering the low level of thrust, one would think it’s almost
    impossible to remove magnetic field interference for the MET.
    Sure Maybe in Intergalatic Voids, but we dont have those handy.

    • Robert June 19, 2018, 13:42

      The EMDrive hasn’t been falsified. Some people can’t replicate it or have issues with there setups but no has yet definitively proven Roger Shawyer’s results aren’t real.

      • Ron S. June 19, 2018, 16:16

        “no has yet definitively proven Roger Shawyer’s results aren’t real”

        Science doesn’t work that way.

  • J. Jason Wentworth June 19, 2018, 15:01

    Arthur C. Clarke pointed out in “The Promise of Space” that many even highly-qualified scientists and engineers who were well-versed in the physics of rockets doubted that they could produce motion in the vacuum of space (and even that their propellant combinations could burn in a vacuum), and:

    “They felt in their bones” (his words) that such a device, releasing a “mere” stream of gas into an infinite vacuum, couldn’t produce motion, despite Goddard’s vacuum chamber tests of small rockets. Only the space-capable V-2 ballistic missile dispelled all doubts that rockets can indeed produce thrust in a vacuum. Also:

    The only way we will ever know, with certainty, whether any of these novel non-rocket space drives actually work (or do not) is to test them in space–in suborbital, orbital, and/or Earth escape (solar orbit) flights, with the devices pointed in various directions to rule out the possibility that they might be reacting against the terrestrial or solar magnetic fields. Otherwise, we will be forever arguing that the laboratory test set-ups weren’t (or were) proper, or that the instrumentation was (or wasn’t) sufficiently sensitive and/or properly rigged. Ion engines were first tested in suborbital and orbital space flights (SERT I and SERT II) to see if they would really work–and after that, for how long–in free fall and then free orbit, under the vacuum and magnetic conditions in space.

    • Ron S. June 19, 2018, 16:18

      That there were fools 100 years ago is no excuse for the vanishingly thin claims of modern mavericks.

      • J. Jason Wentworth June 20, 2018, 5:52

        Gravitational and inertial forces aren’t quite indistinguishable (which Arthur C. Clarke also pointed out, in one of his essays about possible lines of investigation into exotic propulsion systems). If you were aboard a spaceship accelerating at 1 g, your weight would register the same on a scale located anywhere on board, from the stern to the bow, but:

        On Earth, while you would be under 1 g on the surface, your weight would change if you went down into a mine (or into an oceanic trench, aboard a bathyscaphe), or up into the atmosphere or into space, closer to or farther away from the Earth’s center. Now, this difference doesn’t necessarily mean that any of the exotic space drives work, but it does suggest–just as Einstein’s very basic question (“What do we mean when we say that two events are simultaneous,” which led him to formulate relativity) illustrated un-examined (and previously un-conceived) small aspects of the universe whose implications turned out to be profound–that there may be overlooked or un-thought-of corners of physics that might turn out to enable non-rocket propulsion (the Cannae Drive is a microwave radio frequency photon rocket, so it should work, although not with high energy conversion efficiency), and:

        If the experiments are paid for by the experimenters, or–even if NASA-funded–they are inexpensive (sounding rocket-borne space flight tests would be), they’re worth trying. At the very worst, physics as known will be on an even firmer footing, if they don’t work (and physics has gaps–in the Standard Model, gravity “stands alone” from the other fundamental forces, which have not been unified in a general field theory, as Einstein and others have attempted to do).

      • J. Jason Wentworth June 20, 2018, 6:14

        They were wrong about rockets, but they weren’t fools–they were prominent physicists and mathematicians of the 1920s – 1940s, who were engaged in fundamental research. One of them was Professor Bickerton of the British Association for the Advancement of Science, and:

        Dr. Edward Purcell, who famously (or infamously) declared in his 1960 Brookhaven lecture (“Radioastronomy and Communication Through Space”) that interstellar travel was impossible, saying that “all this stuff about traveling around the universe…belongs back where it came from, on the cereal box,” was no fool, either. He was just wrong, having assumed that only relativistic matter/antimatter propulsion would be used (a concept whose huge requirements he attacked), not having considered “Sun-diver” solar sails, laser-pushed lightsails, or ion drive or nuclear rocket propelled world ships traveling much slower than light. It wasn’t a lack of intelligence on his part, but a paucity of imagination (a mental commodity that Einstein considered to be very important for solving scientific problems).

        • tesh June 20, 2018, 10:18

          Is it certain that he was wrong? The jury is still out for me.

          We are vary, very, very far away from even sending the tiniest probe imaginable to our nearest stellar neighbor let alone a world ship using the tech you mentioned. Vast amounts of energy and infrastructure will be required even for that tiny probe and the time likely required for us to have the same (scaled up) set for humans we may have already left this plane in quite another way…

          • J. Jason Wentworth June 21, 2018, 3:36

            Interstellar travel isn’t difficult, and it has already begun (we don’t even need to provide all of the energy to do it, as freeloading off Jupiter’s gravity provides much of the needed solar escape velocity); the issue is the transit time. Even here, we already have an engine that could accelerate an interstellar probe up to at least 1% of the speed of light, and possibly up to 5% or even 10% of c, depending on our level of cleverness:

            Our Sun can “blow” close-flyby (“Sun-diver”) solar sail probes out of the Solar System at such velocities. The same sail materials technologies that are being developed for the Breakthrough Starshot project (the giant laser array-pushed, 20% of c lightsail starprobes) could also be employed for Sun-diver solar sail starprobes, whose sails could be made of graphene, or refractory metal foils (or laminates or woven matrices). Such sails would be deployed (perhaps partially at first) behind a shadowing occulter (which could be made of–or coated with–hafnium carbide, an extremely high-temperature-resistant solid compound) during its approach to the Sun, then would emerge from behind the occulter at around perihelion, to catch the strongest possible sunlight pressure that the sail could withstand, and:

            The payload could be fitted with an erosion shield, and it could use alphavoltaic or betavoltaic fission batteries (with rechargeable chemical batteries) to power its instruments and communications laser during the interstellar cruise. Near the target star, the probe could use photovoltaic cells for power (radiation-hardened and radiation damage self-healing transistors and solar cells already exist).

            • tesh June 21, 2018, 18:18

              You mention lots of possibilities and ifs and buts. Though much of the individual “bits and pieces” maybe within grasp (though I’m not wholly convinced they are) to send a tiny probe out of Sol, they are have not been assembled for that purpose and this will unfortunately remain the case for the remainder of my life time (30-50 yrs) – and possibly much longer.

              True interstellar probes will likely not be sent out in my life time and interstellar travel (with humans) will still be only written about when my grandchildren (if my kids have children) are contemplating immigrating to Mars or the Moon for their careers.

        • Ron S. June 20, 2018, 15:13

          My main point seems to flown past you while you latched on to a single objectionable word I used. That’s a nit which I will happily concede. What you didn’t notice me saying is that the existence of a historic and unrelated error is never an acceptable excuse for any purported scientist to fail to conduct proper and reproducible experiments in support of a hypothesis, especially one containing an extraordinary claim.

          • J. Jason Wentworth June 21, 2018, 3:06

            No, you missed mine. Without a flight test in space, the EmDrive issue (and probably those of other purported exotic space drives, such as the Mach-Lorentz Thruster) will forever remain an unresolved argument–“No, it doesn’t work!” / “Yes it does–the lab test rig wasn’t sensitive or isolated enough!” Also:

            There are many cases of inventions that were tinkered-up long before the principles upon which they work were discovered (the whip [whose loud crack is a tiny sonic boom created by its tip] and the boomerang are just two examples), so the lack of a fleshed-out theory of the EmDrive’s supposed thrust production doesn’t trouble me. If an in-space test shows that it produces acceleration, its operating theory can be worked-back to. While I doubt whether the EmDrive would produce acceleration in space (the Mach-Lorentz Thruster and the Cannae Drive appear more promising–or at least less unpromising), a suborbital or orbital test of the EmDrive would settle the matter. Even if it doesn’t work (which I think would be the most likely outcome), it might serve as a point of departure by inspiring other concepts (Robert Forward worked on a few rather similar exotic propulsion concepts that haven’t yet been tested).

            • Ron S. June 21, 2018, 10:23

              Please pay attention to the investigations being done. There is nothing to test. There is nothing to support funding for what you (among others) suggest. All we have is a theoretically and experimentally unsupported hypothesis.

              • Robert June 21, 2018, 13:43

                That’s a blatantly false statement.

                • Ron S. June 21, 2018, 22:16

                  Go back and read my first comment on this article and then familiarize yourself with Bayesian analysis. The data to date favor the null hypothesis.

                  Further, as I already stated, there is no theoretical basis to favor something other than systematic error and measurement error (by the proponents) the experimental data to date.

                  On the latter point I direct you to a description of “tooth fairy science”, a description that fits.

                  You are of course welcome to believe what you wish.

                  • Robert June 22, 2018, 12:21

                    The Mach Effect device has a definite theoretical basis and experimental support from several independent sources as well as support from NASA and other research institutions. If it were ‘tooth fairy science’ it wouldn’t and I seriously doubt Paul would have allowed the topic included here or that Marc Millis would even write about it here. They were both correct to do so.

                    • Ron S. June 23, 2018, 7:56

                      A wild hypothesis, not a sound theoretical basis. Paul discusses many fringe topics in CD related to interstellar travel, which I support since there is indeed much we do not yet know. That does not mean I accept extraordinary claims with weak experimental support. Sticking “NASA” or any generally respected name on something does not make it credible. As I said believe what you wish.

  • Geoffrey Hillend June 19, 2018, 16:20

    One has to understand the physics which supports the EmDrive. It’s only uses radiowaves or microwaves and I don’t see how there can be any new physics with that other than photons leaking or going through the cavity body or when the radiowaves heat the body of the cavity and cause the emission of a small amount of thermal infrared blackbody radiation. It would be nice to have a simple solution to the interstellar travel problem, but we really have to put time energy and money into new physics especially with the FTL.

    There is a difference between Mach’s principle and general relativity. According to Mach motion and rotation centrifugal force don’t exist. p. 239. ibid. This idea reminds of the idea of Descartes Einstein wrote about his book on Relativity, Crown, 1961. P. 136. “Space is only the extension of bodies and without bodies there is no space.” Space is undifferentiated from bodies so space was thought to be non existent by the philosophers of the past. Space really does exist. It has energy in it theorized by the Heisenberg uncertainty principle and proven by the Casimir effect. There is also the Lorentz Covariance of general relativity. “the laws of physics stay the same for all observers that are moving with respect to one another within an inertial frame.” Lorentz Covariance, Wikipedia.

  • Geoffrey Hillend June 19, 2018, 16:28

    My point was when we remove the false positives with the EmDrive, there will not be any new physics. The false positives would be small hard to detect emissions of radiation like the infrared thermal radiation from the radiowaves heating up the cavity body or any other anomalies which can be explained by ordinary physics when the testing has not been rigorous or strict enough.

  • Geoffrey Hillend June 19, 2018, 17:05

    Gravitational and inertial forces produce effects that are indistinguishable. This is the principle of equivalence. P. 220 Cosmology, 2nd ed., Harrison. Mass times acceleration equals gravity. Acceleration equals gravity. Inertial mass equals gravitational mass p. 222, ibid. With general relativity, inertia must be the effect of matter and energy on space-time. If we add kinetic energy to a rocket, then its momentum increases when we reach relativistic speeds and the rocket experiences a length contraction. It’s the kinetic energy that we add which is what that makes it more massive which is explained by general relativity.

    • J. Jason Wentworth June 20, 2018, 7:29

      In his 1979 non-fiction book about the possibilities and ramifications for/of ETI contact (“Extraterrestrial Encounter: A Personal Perspective,” with Foreward by Professor A. E. Roy, see: http://www.abebooks.com/servlet/SearchResults?sts=t&cm_sp=SearchF-_-home-_-Results&an=Boyce%2C+Chris&tn=Extraterrestrial+Encounter&kn=&isbn= ), science fiction author Chris Boyce, in addition to examining the possibilities of von Neumann probes in detail (among many other things), wrote (in Appendix 2) in some detail about a novel starflight method I had never heard of before:

      After reviewing the Einsteinian universal speed limit of c and why it exists, he covered Professor John Wheeler’s Superspaces, which–although apparently permitting higher velocities within them–don’t contravene General Relativity, and are actually based on GR, and:

      Then he speculated about (and derived the appropriate equations to describe it) a possible method for turning a starship into what he called a Relativistic Black Hole (RBH), possibly allowing either rapid wormhole-type travel between elsewhere (and elsewhen), or virtually “time-frozen” (for the ship and its occupants) interstellar travel. He used the term “Relativistic Black Hole” because the ship would only be a black hole to outside observers, not to its occupants. At sufficiently high near-c velocities, the combination of the starship’s relativistic mass increase and density increase (due to its relativistic shortening) could give it the mass and density of a black hole. Also:

      Boyce did not say that this speculated method would certainly work (he put it forward as a possibility), but that it might, and that–when (hopefully not “if”) near-c spaceflight becomes feasible–it would be worth trying. I agree, although I’m certain that I’ll never live to see the ability to try it become possible (and he was sure of that as well). The point is that we don’t know everything, and that some as-yet-un-conceived-of method of reaching the stars quickly may one day be discovered. That is why it pains me to read confident declarations that “nothing new about physics can be learned from testing the EmDrive [or the Mach-Lorentz Thruster].” In addition:

      Those who make such statements are probably right, but they might be entirely wrong, and such self-assurance has delayed advancements many times in the history of science. (Knowledge of the true nature of meteorites, ball lightning, and red sprite & blue jet high-altitude storm-related plasma phenomena are just a few examples of attitude-delayed scientific discoveries.)

  • Harry R Ray June 20, 2018, 9:52

    Speaking of “thrusters”: An absolutely INGENIOUS use for the Shkadov Thruster! ArXiv:1806.05203. “Life Versus Dark Energy: Howan advanced Civilization could resist the Accelerating Expanse of the Universe.” by Dan Hooper. PREMISE: Even though this is ONLY going to be a problem 100 billion years from now, because stars can be moved ONLY VERY SLOWLY, YOU HAVE TO START NOW! This also ASSUMES “cosmological constant” Dark Energy” and NOT the BAD forms(quintessence or phantom energy). Dyson Sphere blackbody radiation models have already been derived and astronomers are searching for them based on these models(in fact, Jason Wright has a fairly decent candidate provided that a GAIA “bad fit” is an ARTIFACT and not an actual TRUE discrepancy – keep your fingers crossed!). Similar models for Shkadov Thrusters should be developed PRONTO, and an active search should commence ASAP!

  • Geoffrey Hillend June 20, 2018, 15:57

    The philosophy of science is that it’s principles are assumed to be mind independent and objective especially first principles. If an idea does not fit into these it is considered wrong. Scientists will test such an experiment anyway to make sure and if it is wrong they move on to another idea and experiment. The psychology of scientific thinking has something impersonal about it, so that a good scientist does not worry if an idea is not supportable by principles. The scientific intuition has a detachment from emotion, so that they are not too personally identified with their ideas. Kepler’s five perfect solids is a good example.

    One of the good characteristics of the Alcubierre warp drive idea is that it’s occupants do not feel any inertial affects from acceleration and FTL speed since according to physics of general relativity they are in a free fall geodesic. Consequently, there is no time dilation because the warp drive drags it’s local space reference frame with it. Time moves at the same rate inside the warp drive as it does everywhere outside it in normal space or as on Earth. Time only slows down in a spacecraft at relativistic speeds without a warp drive. There is no time in a black hole due to the extreme gravity. Black holes can only be detected indirectly by the starlight they block, their strong gravity, emission of black body radiation from their accretion disk etic. If it looks like a black hole, then it must be one. Anything that falls into a black hole is crushed down to the infinitesimal.

    • J. Jason Wentworth June 21, 2018, 2:32

      Not quite, as Boyce pointed out. At a velocity extremely close to that of light, a vehicle’s mass would be virtually infinite, it would be of virtually zero length along its direction of motion, and its passage of time would be all but zero, ^to outside observers^. But to the ship and its occupants, nothing would be unusual–its mass and length (and the crew members’), and the time as measured by its on board clocks, would all be perfectly normal, and:

      The ship’s mass, length, and passage of time, as outside observers would see them, would be well in excess of those parameters’ values for stellar-mass black holes. They would be more akin to those of the super-massive black holes at the cores of galaxies, yet the ship’s and the crew’s circumstances–to them–would be no different from ours (particularly if the ship was accelerating at 1 g [except that their 1 g weight would be the same everywhere onboard, while our 1 g weight changes if we go below or above the Earth’s surface]). The appearance of the surrounding universe would certainly be different to such a starship’s crew, though.

    • J. Jason Wentworth June 21, 2018, 3:45

      The philosophy of science is out of date regarding science’s principles being mind-independent. The observer effect in quantum physics experiments shows that in those cases, the experimenter’s mind is part of the experiment and affects (and in some cases, such as the photon/slit experiment where the photon appears as either a particle or a wave) or even determines the result. Einstein didn’t like these magical aspects of quantum physics (especially what he called “spooky action at a distance”), but the universe didn’t agree with him. :-)

      • Mephane June 25, 2018, 7:21

        > The observer effect in quantum physics experiments shows that in those cases, the experimenter’s mind is part of the experiment and affects

        This is not correct. The “mind” plays no role whatsoever. What is often used in this concept is the term “measurement”, which means the specific physical interaction between the measured system and the measurement device. In other words, a quantum mechanical measurement will affect an experiment whether a human ever looks at the data or not. The word “measurement” itself is a bit misleading, better would be “interaction”.

        • AlexT June 29, 2018, 3:25

          I suppose that belief in “mind” influence to quatntum experiments is cause by noncorrect representation of quantum mechanic by many of science popularisation sources.
          I suppose that every engineer that have to use different type of measurements in his job knows well that every instrument has influence on the measurement results, the difference that in quantum mechnic experiments this dependence (influence) is many orders higher.

  • Antonio June 20, 2018, 17:10

    I can’t understand at all why so much time is devoted to the EmDrive BS by any scientist.

    • J. Jason Wentworth June 21, 2018, 2:06

      The same thing was said for centuries by scientists regarding meteorites (“Everyone knew that stones couldn’t fall from the sky, because there were no stones in the sky”)–even after actual meteorites were given to scientists by the meteorite fall witnesses (the scientists said that the strange rocks were struck by lightning, or came from volcanoes), and:

      Johannes Kepler could easily have dismissed as errors the few tiny–no more than eight minutes of arc–angular measurement discrepancies in Tycho Brahe’s observations of the positions of Mars, which eventually showed him (after Kepler’s years of attempts to make the data fit a circular orbit) that the planets follow elliptical rather than circular orbits. Had he done so, he might never have formulated his three laws of planetary motion, from which Isaac Newton formulated his laws of motion and gravitation, which Einstein used as the basis of general relativity, and speaking of Einstein:

      For some time his ideas were also rejected out of hand because the premises or relativity sounded absurd. As in the above cases, observations and/or experiments showed that Einstein was right. We do not yet know if some novel–if subtle–effect is behind the EmDrive results (and/or any of the other purported exotic space drives), but refusing to follow the evidence wherever it leads just because it seems absurd is unscientific, as the history of science shows. Maybe there are no space propulsion system principles other than the Newtonian (action-reaction) one, which also includes photon, magnetic, and stellar wind sails and charged tethers. But if other such space propulsion principles do exist, we will never find them if we do not look and test for them, and if we do find any, it or they will profoundly affect far more than just space travel.

  • Michael Fidler June 21, 2018, 2:21

    See R.C Jennison work on interia:

    Jennison, R.C. “Relativistic Phase-locked Cavities as Particle Models”, J. Phys. A. Math. Gen. 11, 1978, pp 1525-1533.

    Jennison, R.C. “Wavemechanical Inertia & the Containment of Fundamental Particles of Matter”, J. Phys. A. Math. Gen. 16, 1983, pp 3635-3638.

    Jennison, R.C. “Proper Time, Proper Length & Some Comments on the Concepts of Time & Distance”, 1988, incl. in Vol. 1 of Duffy & Wegener (q.v.), pp 73-83.

    Jennison, R.C. “A New Classical Relativistic Model of the Electron”, Phys. Lett. A., Vol. 141, Nos 8-9, 20 Nov 1989, pp 377-382.

    Jennison, R.C., Jennison, M.A.C. & Jennison, T.M.C. “A Class of Relativistically Rigid Proper Clocks”, J. Phys. A. Math. Gen., 19, 1986, pp 2249-2266.

    • Michael Fidler June 21, 2018, 16:16

      Confinement of Light: Standing Wave Transformations in a Phase-Locked Resonator.
      L. J. Reed
      Torrance CA
      Electromagnetic resonant wave interactions in a phased-locked resonator at rest and in motion are compared. The origin of mass and inertia as a standing wave interaction in a phased-locked cavity as demonstrated in work by Jennison is reviewed and phase relationships illustrated. For matter (composed of resonant EM standing waves) in motion, the Lorentz contraction is interpreted as a physical wavelength compression due to variation in EM field energy density as measured by vacuum refractive index K
      PV. Dipole radiation emitted from a phase-locked resonator in motion is described. A graphical representation of Ivanov-LaFreniere standing wave transformations is shown. Experimental possibilities for potential phase conjugate wave phase-locked resonator development are discussed including inertia modification and propulsion.

      electromagnetic (EM), standing wave, travelling wave, phase-locked resonator, confined light, Lorentz, mass, frequency, oscillator, inertia, phase conjugate waves, de Broglie, Doppler, photon, electron.


  • Geoffrey Hillend June 21, 2018, 15:48

    Quote by J. Jason Wentworth. “Not quite, as Boyce pointed out. At a velocity extremely close to that of light, a vehicle’s mass would be virtually infinite, it would be of virtually zero length along its direction of motion, and its passage of time would be all but zero, ^to outside observers^. But to the ship and its occupants, nothing would be unusual–its mass and length (and the crew members’), and the time as measured by its on board clocks, would all be perfectly normal,” This idea is NOT supported by general relativity. I very much like it to be true but unfortunately it isn’t. 1) The length contraction of GR is not an illusion as proven in the LHC (Large Hadron Collider). Those protons are accelerated to 99.9999 percent of the speed of light. They undergo length contraction so they are smaller and are flat like pancakes. They also have many additional virtual quarks and gluons in addition to the valence quarks and gluons of rest mass. E equals MC squared so that kinetic energy is momentum (mass times velocity) which can be converted into new particles and at relativistic speeds since those protons are 7,000 times their rest mass. Also the time on a neutron star is 30 percent than normal space due to the extreme gravity. This is not a good environment for clocks and astronauts. Consequently a ship near infinite mass will crush the ship, occupants and any instrumentation. Astronauts will feel more and more g forces as the ship approaches the speed of light. One has to do the thought experiments to see if an idea conforms to GR. It’s the system of physics and its rules that are invariant, mind independent and objective. If it does conform to these principles, then it does not represent physical reality but an imaginary view like some ideas in science fiction.

    • Robert June 22, 2018, 12:45

      “Consequently a ship near infinite mass will crush the ship, occupants and any instrumentation.”

      I don’t think that’s correct. Consider the frame you currently exist in. You are already moving at very near c wrt some observer somewhere in the universe. Do you feel infinitely heavy and are you being crushed? If you were then you could always tell you were moving and how much which contradicts Relativity. And how would to your body know which fast moving observer to compute these effects in reference to anyway?

      Just because an observer sees you as thin as a pancake going by doesn’t mean you actually are within your own reference frame.

  • Geoffrey Hillend June 21, 2018, 15:49

    Time moves 30 percent slower on a neutron star than normal space.

  • Geoffrey Hillend June 21, 2018, 16:24

    Excuse me, It’s special relativity that concerns length contraction.

  • Geoffrey Hillend June 21, 2018, 21:13

    Michael Fidler: Thankyou for posting this paper: Confinement of Light: Standing Wave Transformations in a Phase-Locked Resonator. It shows how light can acquire mass due to the effects of inertia and a moving reference frame which is proven by special relativity.

  • Geoffrey Hillend June 21, 2018, 22:05

    If it does NOT conform to these principles, then it does not represent physical reality but an imaginary view like some ideas in science fiction.

  • Geoffrey Hillend June 22, 2018, 16:29

    Quote by Robert: “I don’t think that’s correct. Consider the frame you currently exist in. You are already moving at very near c wrt some observer somewhere in the universe.” I don’t believe this to be correct. This idea you mention deals with astrophysics and our perception of space on the large scales and different spaces moving at different speeds relatively to each other which is not the same one adding energy to an object to make it accelerate it in a moving reference frame. The time is a variable which is also involved. This idea gets into some serious astrophysics so I don’t wish to explain here.

    My scientific intuition tells me if a neutron star experience a 30 percent slower than normal time dilation, then that is how much gravity one would have to endure in order to make time go that slowly since in GR an accelerating reference frame is equal to the gravity of a rest state. One has to have a stronger gravity than what one would experience on the surface of a neutron star to make time go even slower.

    • AlexT June 29, 2018, 3:44

      Should we conclude from your explanation that astrophysics laws allaws things that are no allawed by physics laws?

  • Geoffrey Hillend June 22, 2018, 16:50

    The Hubble constant must be included.

  • RAS June 27, 2018, 6:46

    Interesting posting about the background on Tajmar’s testing. I leave it up to the reader to draw their own conclusions.


  • RAS June 29, 2018, 6:14


    Find attached Jim Woodward’s June 2018 critique of Tajmar’s spring 2018 Mach Effect Gravity Assist (MEGA)-drive Seville report that Dr. Woodward sent out to his email distribution on June 25, with some editorial clean-ups from me. I hope you find it informative.

    Best, Paul March, Friendswood, TX”

    From here where you’ll find the attached report.


  • AlexT July 2, 2018, 2:41

    When I compare commenters reaction on EMDrive and MACH drive concepts and reaction on the Dipole drive (that is published on this site later).
    I can see that exactly same commenters that are very pessimistic relatively EMDrive and Mach drive concepts, very optimistic relatively the Dipole drive concept, when Dipole drive conteins so obvious authors mistakes , faults and non correct application of known physical laws.
    Very strange bias.

  • Dan O August 9, 2018, 16:17

    We can already make a worldship. Project Orion conceptualized such a vessel already. Largest model capable of reaching 60% the speed of light and the bigger the better. With a rotating living sectioned interlocked during acceeration extended and rotating during cruise. With such a ship a physical shield could be used to to shield the ship from micro impacts. Make it out of graphite to deal with heat and radiation created. We could launch her from a moon or mars base we spend the next few years setting up. We have the texh to go to alpha centauri. We just need a probe to go first to see if its worth it.