Having NASA's version of skunk works standing behind the device with peer-reviewed data is a pretty sure sign it's real, however.
Not really. Peer-review is not perfect and only means that they found reviewers who found the paper acceptable. It is a step up from crackpot papers, but you should in no way take this as a sign this is real.
Uppi, if you read the article would you mind commenting on the physics arguments for and against the EM Drive effect? You're much better versed in physics than I am and better at explaining it all to boot.
Thanks!
Sure, let's get started with the theoretical side. The physics in the paper is a load of crap. The mumbo-jumbo about interpretations of quantum mechanics misses an important point: The reason that these are called interpretations is that they lead exactly to the same physics. So any explanation of a physical effect that relies on a particular interpretation and cannot be reformulated in another interpretation is extremely likely to be wrong. Of course, there might be an as of yet undiscovered difference between interpretations (at which point they would stop being interpretations), but many theoretical physicists have tried to discover any and failed.
Within the current framework of physics the effect they claim is impossible. Generating thrust without ejecting something is a violation o the conservation of momentum. There is no guarantee that our universe conserves of momentum, but it is mathematically linked to the symmetry of space (it does not matter where I perform an experiment). If this device was violating momentum it would require the space at one end to somehow have different properties than the space at the other end. I might not be fully convinced that space at some distant point of the universe might be different, but I would say that we should have noticed by now if space behaved differently on the scale of a meter (Obviously you can induce changes to space, w.g. by applying an external magnetic field, but then the device would be pushing against that field and you would be in the real of conventional physics again).
You can get around the restrictions of conservation of momentum by pushing against "something else". According to Relativity, energy can be converted to mass and momentum. If we want to keep conservation of energy (which results from time symmetry, i.e. under the same conditions I get the same result, no matter when I perform the experiment), there is an upper limit to that. The formula for the conversion is E = sqrt(m^2*c^4 + p^2*c^2), (which reduces to the famous E = m*c^2 for a particle at rest). To maximize the momentum p for a given energy E, we have to set m=0 (which would be true for photons) and get E = p*c as an upper limit. So if you have nothing to push against, creating and emitting photons is best possible option.
If you take this upper limit, you see that the generated thrust is 3 orders of magnitude higher than if you would create and emit photons.
That means that if you want to conserve both energy and momentum you would need some extra energy from somewhere. The pseudo-physical explanation given in the paper suggest that you can siphon vacuum energy and somehow use that for a drive. As vacuum energy is very poorly understood, there is some wiggle room here, but it is tiny: QFT suggests that this vacuum energy should be extremely large, but actual measurements of the cosmological constant reveal it to be quite small (the prediction was off by over 100 orders of magnitude and is called the most embarrassing misprediction in physics of all times). In fact, it is so small that the vacuum energy in the device is more than 15 orders of magnitude smaller than the device would require to generate the specified thrust. I suppose that there is still a small loophole, because the device could siphon vacuum energy from a huge volume (larger than the earth), but why and how would it?
If the claims about this device are true, there has to be a very serious bug in our current understanding of physics. You would have to tear down at least one of the pillars of modern (and maybe even classic) physics.
But, of course, this might well be the case, and we would be very unscientific, if we threw away evidence because it does not fit our theories. Nevertheless, extraordinary claims should require extraordinary evidence and I am not seeing that. In my view, the measured force is most likely due to thermal effects, because you cannot heat anything and not expect it to move. And indeed, one of the measurement shows that in one direction (perpendicular to the supposed thrust), the displacement is 8 micrometer (which they explain by thermal expansion), while the so called thrust only results in a displacement of 4 micrometers. This shows that thermal expansion is at least on the same scale as the supposed effect. They make some handwaving arguments why thermal expansion should lead to a different curve, and there is some merit to that, but it is far less convincing than it would need to make me accept such an extraordinary claim.
The potential for this effect for both practical applications and our theoretical understanding of physics would be huge if it were true. So if they have any reasonable suspicion that this is a real effect, they should try to further investigate this effect until they can unambiguously confirm it or find out were they went wrong. I just would go differently about it and try to find out why this works until I build it bigger and in space. But that might be the physicists point of view and I admit that the evidence would be pretty compelling if they took this thing and flew it to Mars and back.
OMG... How many middle east countries do you need to destroy to amortize that?
