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EM Drive System No Longer Further Confirmed

Vaermina said:
Honestly Einstein would be ashamed of some of the so called scientists in this thread. Clutching onto their existing mathematical models like misers clutching gold coins.

Einstein would drive down there himself to see if the thing actually worked and if so revise his mathematical models till everything fit with the new information. And be absolutely ecstatic about the whole thing because it confirmed his world view that there was always new things to learn.
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*eye roll*
 
Vaermina said:
I assume you have something to contribute other then showing off your surely mythic level eyerolling abilities?
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I don't know are you done being super edgy and implying that if only those darned scientists weren't so dogmatic we'd all be living in gravy-land?

See this?

Vaermina said:
Honestly Einstein would be ashamed of some of the so called scientists in this thread. Clutching onto their existing mathematical models like misers clutching gold coins.

Einstein would drive down there himself to see if the thing actually worked and if so revise his mathematical models till everything fit with the new information. And be absolutely ecstatic about the whole thing because it confirmed his world view that there was always new things to learn.
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This isn't contributing this is you casting aspersions and not actually having the slightest understanding of what was being pointed out earlier in the thread.

pheonix89 said:
In case you skipped to the end of the thread, Vorpal ripped these guys a new bleed hole for their absolutely shit theoretical explanation.
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I think you missed Vaerminas previous post which amounted to "What the fuck do 'theorists' know.
 
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Vaermina said:
Honestly Einstein would be ashamed of some of the so called scientists in this thread. Clutching onto their existing mathematical models like misers clutching gold coins.

Einstein would drive down there himself to see if the thing actually worked and if so revise his mathematical models till everything fit with the new information. And be absolutely ecstatic about the whole thing because it confirmed his world view that there was always new things to learn.
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Einstein spent his twilight years trying to disprove the quantum mechanics that he had helped found. He was not the paragon of open-mindedness that you're trying to paint him out to be.

And the point that you're missing is that we're "clutching" at these models because they are INCREDIBLY well-supported by the evidence we've collected so far. It would be akin to someone claiming they have proof that Sun is an optical illusion based on something they saw while looking at the Moon through their home telescope. Literally every experiment conducted for the past several centuries says that what Dr. White is advancing is impossible, which is a humongous weight of evidence to try to refute.

We're not even saying that this isn't an interesting result that warrants further study. We're just saying that it's exceedingly unlikely that it is what Dr. White thinks it is.
 
pheonix89 said:
In case you skipped to the end of the thread, Vorpal ripped these guys a new bleed hole for their absolutely shit theoretical explanation.
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Which assuming Vorpal was right only means the math they used to explain how the engine works was wrong.

There is an interesting fact about the universe however that you seem to be ignoring. If something is shown to work in a repeatable way by multiple sources and the math says it shouldn't, the math is likely in the wrong.
 
Vaermina said:
Which assuming Vorpal was right only means the math they used to explain how the engine works was wrong.

There is an interesting fact about the universe however that you seem to be ignoring. If something is shown to work in a repeatable way by multiple sources and the math says it shouldn't, the math is likely in the wrong.
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You would have a point if this had in fact been shown to work in a repeatable manner by multiple sources. Too bad it hasn't.
 
Vaermina said:
There is an interesting fact about the universe however that you seem to be ignoring. If something is shown to work in a repeatable way by multiple sources and the math says it shouldn't, the math is likely in the wrong.
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Nobody's even arguing that they're not measuring force, as far as I'm aware. What people are calling bullshit on is their explanation for what is causing that force.
 
Overturning a huge swath of our scientific knowledge requires extraordinary proof. Measuring an almost-unmeasurable force on a pendulum when pumping in a very significant amount of energy is... not particularly extraordinary. Especially when the device in question is very poorly understood and could be (and almost certainly is) interacting with the surrounding environment in any number of ways.

Vaermina said:
Actually people were saying the entire thing was bullshit not just the math.
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Quote somebody in this thread denying that the device produced a force.
 
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Vaermina said:
There is an interesting fact about the universe however that you seem to be ignoring. If something is shown to work in a repeatable way by multiple sources and the math says it shouldn't, the math is likely in the wrong.
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Or that they have common sources of error that they haven't properly accounted for.

Case in point, Wikipedia on th EM Drives says that the previous set of tests at Eagleworks returned about 90-100 μN of force from 17 W of power. Testing it near vacuum, they measured about 50 μN of force (about half as much) from 50 W of power (nearly three times as much). Now, maybe part of that's because the vacuum adapted components might be substantially less energy-efficient, but otherwise it looks like over half the force they were measuring was coming from atmospheric effects.

And you can certainly object that they're still measuring a force in a vacuum, but that only rules out atmospheric effects and not other sources of error.
 
Ehh I still remain cautiously hopeful. Yes I realize the chance this becomes true went from a needle in a haystack to a needle in an entire cornfield, but hey there's always a chance, as utterly minuscule as it may be.
 
Bah, science as a rational project is but a fleeting ahistorical myth dreamed up by rationalists desperate to sort knowledge into tiny little boxes.

Down with the tyranny of the scientific method! Burn down the establishment! Solidarity! Stand together for (Epistemic) Anarchism!

Cite not Einstein to support the cause but Lakatos or Feyerabend (you'll find a lot more argument for what's being pushed in Against Method than anything Einstein wrote.)


That said, the EM Drive is still almost certainly bullshit though. I'll be (very) pleasantly surprised if it turns out to be anything but, but I'm not going to hold my breath.
 
Still doesn't change anything.

You have that backwards, Boristus. Harold 'Sonny' White is actually employed by Eagleworks Labs at NASA, and the "quantum vacuum thruster" is his idea to explain the EmDrive. In contrast, van Tiggelen is at CNRS in France (as are all co-authors), whose work has nothing to do with the EmDrive. One can find a preprint of van Tiggelen's paper here, which builds on an older discussion started by Feigel, with a preprint here.

I wonder if van Tiggelen is even aware that EmDrive exists, but regardless, saying 'it' has been accepted for publication in the thread about EmDrive is grossly misleading at best, because such a statement implies that the antecedent refers to the EmDrive.

There is no connection between van Tiggelen and the EmDrive outside the hallucinations of some subset of EmDrive's proponents. The EmDrive had several 'explanations' already, from Shawyer's confusions on special relativity to Sonny's pathetically obvious nonsense about 'Q-thrusters'. Perhaps this time will be the charm, but until such an account appears, I think a more plausible explanation given the track record is that a near-pathological inability to avoid blatant untruths is not limited to Sonny.

Energy conservation for the electromagnetic field requires a Poynting vector S = E×H giving the electromagnetic energy flux density. For crossed (perpendicular) electric and magnetic fields, this is nonzero, and therefore we can say that electromagnetic energy is circulating even in the absence of electric charges, indeed even if the fields are unchanging and uniform. This shouldn't show up classically as a net force over bulk neutral matter, but both Feigel and van Tiggelen argue that an appropriate quantum-mechanical generalization can indeed be measurable.

The Feigel effect is wrapped up in the so-called Abraham–Minkowski controversy, which is a surprisingly contentious mountain made out of a tiny molehill. It is center-stage to Feigel's paper and covered in the introduction of van Tiggelen's. Elsewhere, van Tiggelen correctly says that Feigel doesn't actually address the controversy at all (despite Feigel's claims), but incorrectly implies that the controversy is a real problem to begin with. To summarize the issue, the dispute is over the electromagnetic momentum density in a medium. According to Minkowski (1908), it is D×B; according to Abraham (1910), it is E×H/c² = ε₀E×μ₀H; according to Nelson (1991), whose approach van Tiggelen largely parallels, it is ε₀E×H.

One can simply substitute the relations D = ε₀E+P, B = μ₀(H+M), where P and M are polarization and magnetization fields, from which it is easy to see that:
ε₀E×μ₀H = ε₀E×B + M×E/c² = D×B + B×P + M×E/c².​
Fundamentally, Minkowski is right because momentum is the generator of spatial translations, which for the electromagnetic field matches Minkowski's D×B exactly. That's directly implied by Noether's theorem (1915/1918), so people who don't grok that Minkowski is correct are literally a century out of date. The B×P term is the momentum density of the bound charges. Since Nelson derived ε₀E×H by considering the Lorentz force coupling matter and radiation for both bound and free charges, it is not surprising that Nelson's momentum includes both, as ε₀E×H = D×B + B×P exactly. Finally, conceptually both Minkowski and Nelson are leagues ahead of Abraham because in the topological formulation of Maxwell's equations, both the electromagnetic and bound charge momentum densities directly correspond to differential forms that are definable without any constitutive equations or spacetime metric whatsoever, and are therefore more fundamental than the Abraham momentum density (which is quite unnatural).

Practically, though, it doesn't matter: it's just a dispute over book-keeping. It's fine to re-group various terms and perhaps give them special names such as 'canonical momentum' and 'kinetic momentum' and what-not. The only practical problem is that such a proliferation of different conventions can make it difficult to sort out who's done their book-keeping correctly and who hasn't. Van Tiggelen argues that Feigel hasn't done it correctly, but that a similar effect should be present nonetheless.

Quite appropriately, the same kind issues are related to the interpretation of the Feigel/van Tiggelen effects, should they prove real. The setup van Tiggelen is talking about involves a squeezed vacuum (à la Casimir) and an external magnetic field. The ground-state of this setup is a vacuum in the sense of having the lowest energy, so van Tiggelen is not wrong for interpreting his hypothetical effects in terms of virtual particles in a vacuum (or if he is, it's not for those reasons), but... and there's a big but... there's an external system responsible for those experimental conditions.

It's written plain as day in the paper: external magnetic field. So what's responsible for it? In real experiment, you can't just chunk your sources to infinity. It's an interpretational choice to say whether the momentum extraction is from the vacuum field or from an the experimental setup mediated by that field. Once again, it's simply a question of book-keeping conventions.

So what does this have to do with EmDrive? Diddly-squat. Unless the claim is that an external magnetic field in the test chamber is responsible for the EmDrive's force measurements, as that's essential to van Tiggelen's setup, in which case the EmDrive is dead. Literally, if the effect in the van Tiggelen paper is responsible for the EmDrive force measurements, then EmDrive is dead as a useful space propulsion device.

Rather, what's likely going on is that some clueless sods are grasping at anything that even vaguely sounds like the 'Q-thruster' nonsense, regardless of whether it connects to the EmDrive or not, in order to pretend that it has any kind of coherent theoretical basis. Well, I'd prefer to call them lying liars who lie, but foamy might object, and it is certainly possible that some people could be that genuinely nutty.
 
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Speaking of people spitballing explanations for the EM Drive, clearly the drive works because of the quantization of inertia:

Article:
Can the Emdrive Be Explained by Quantised Inertia?
controversial, emdrive, physics, propulsion, science, space

An Introduction to MiHsC - a model for inertia called: Modified inertia by a Hubble-scale Casimir effect (MiHsC) or quantised inertia.

The idea of inertia is that in a vacuum, where there is no friction, objects move along in a straight line at constant speed until you push on them. This tendency was first isolated by Galileo, who rolled balls down inclined planes (balls feel less friction). This tendency, inertia, has always been assumed but never explained.

Meanwhile physics has moved towards a study of information, and it has been realised in the past few decades that when you accelerate something, say, to the right, information from far to the left can never catch up to it, this means there is an information-boundary or 'horizon' to its left which is like a black hole event horizon (it is called a Rindler horizon). A kind of Hawking radiation comes off this horizon, which is called Unruh radiation (it was proposed by Bill Unruh) and is seen as background radiation, but is seen only by the accelerated object.

The new prediction from the model then is that objects with very low acceleration lose inertial mass in a new wa

It has been shown that cone-shaped cavities with microwaves resonating within them move slightly towards their narrow ends (the emdrive). There is no accepted explanation for this. Here it is shown that this effect can be predicted by assuming that the inertial mass of the photons in the cavity is caused by Unruh radiation whose wavelengths must fit exactly within the cavity, using a theory already applied with some success to astrophysical anomalies where the cavity is the Hubble volume. For the emdrive this means that more Unruh waves are "allowed" at the wide end, leading to a greater inertial mass for the photons there. The gain of inertia of the photons when they move from the narrow to the wide end, and the conservation of momentum, predicts that the cavity must then move towards the narrow end, as observed. This model predicts the available observations quite well, although the observational uncertainties are not well known.

(H / T Adam Crowl at Crowlspace )

Three independent experiments have shown that when microwaves resonate within an asymmetric cavity an anomalous force is generated pushing the cavity towards its narrow end.

This force can be predicted to some extent using a new model for inertia that has been applied quite successfully to predict galaxy rotation and cosmic acceleration, and which assumes in this case that the inertial mass of photons is caused by Unruh radiation and these have to fit exactly between the cavity walls so that the inertial mass is greater at the wide end of the cavity. To conserve momentum the cavity is predicted to move towards its narrow end, as seen.

This model predicts the published EmDrive results fairly well with a very simple formula and suggests that the thrust can be increased by increasing the input power, Q factor, or by increasing the degree of taper in the cavity or using a dielectric.



SOURCES - Physics from the Edge, Progress in Physics
Source: Next Big Future

(For those not in the know, modified inertia theories are somewhat controversial as an alternative explanation for dark matter. Still a lot less controversial than the EM Drive and its experimental results.)
 
McCulloch's idea is strange because the inertial mass of photons is zero in vacuum. Well, whatever; let's assume he meant to define m = E/c² instead; since E = pc, that would actually make his starting equations tautologically true. Then offhand, the biggest problem with this "mass is affected by Unruh radiation through a Hubble-scale Casimir effect" idea, which is interestingly vaguely similar to Sonny's (except not based numerology of the Planck force), is that we've seen exactly the same thing before regarding the Pioneer anomaly [arXiv:astro-ph/0612599], where it actually overestimated the anomalous acceleration... which means that it's just plain falsified, because to statistical significance, the anomalous acceleration is the result of thermal radiation.

So ironically enough, the fact that the acceleration in the Pioneer probes is no longer anomalous now provides falsification to McCulloch's modified inertia idea. This is very much controversial and outright far-fringe.

I think you may be confusing this is Milgrom's 'modified inertia', which despite being called the same, is a very different thing, being a path-dependent offshoot of MOND. As far as I know, it never went much of anywhere. However, MOND itself does have a relativistic formulation, so it is indeed far less controversial, though the main problem with things like TeVeS is that they're worse that the 'disease' they're trying to cure. But that's a wholly different story.
 
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