Please watch this Feynman video ten times.

Thank you.

I love this: when somebody complains that the theory of operation is total gibberish, the response is: "But we don't need a theory! Experiment trumps theory!" Then when somebody suggests that one needs much, much stronger evidence before you should even consider tossing out conservation of momentum, one of the most basic principles of physics, the response is "But they have a theory that shows it doesn't violate conservation of momentum".

Rinse and repeat.

I have always been kind of astonished that a group of self-selected tech geeks would repeatedly display such abysmal scientific understanding. Global warming? Not nearly enough evidence for that. Decades of studies and a broad scientific consensus are still not enough to draw an actionable conclusion. But two or three crackpots claim they have a warp drive, and everybody is lining up for their tickets for Alpha Centauri.

Very sad.

Damn. Our evil plot is exposed.

They don't prove any such thing. All they prove is that a bunch of questionable researchers claimed to measure a marginally significant effect, and have been hyping the fuck out of it. Scientific openness is not equivalent credulously accepting the claims of every whacko and charlatain who makes a claim, just because it "hasn't been disproven".

We do know things about the world. Nothing is absolute in science, but some things come very, very close. Conservation of momentum is one of those. You don't toss that aside without utterly overwhelming evidence. There is no such evidence here.

Poor comparison. High-Tc superconductivity was a demonstration of a known phenomenon (zero resistance current) under new physical circumstances. A better comparison might have been the photoelectric effect, which really had no explanation under the then-known laws of electromagnetism. The explanation for the photoelectric effect in fact did require a deep and radical revision of the basic laws of physics: Quantum Mechanics. Sometimes this happens.

These guys have not measured something which clearly requires such a revision of physics, yet they are full of breathless claims about its significance. Red flags all over the place.

If they simply wrote a paper saying "we noticed an anomalous force in this experimental setup, and we don't understand why", then nobody would have a problem with it. They're not doing that. They are claiming that it can be used as a reactionless propulsion system, a claim which is entirely incredible without a solid physical theory to justify it.

They're measuring an anomalous force in an electromagnetic cavity. That's a measurement, a concrete fact. They're claiming that they'll be able to make a starship with it. That's beyond any credibility. It's totally delusional.

Have you actually read the paper? Hint: there's a very, very good reason why it is not in a peer-reviewed journal.

This is way more believable than the answer they give.

If I were to peer-review a paper on this, I would insist on a plausible physical explanation for the claimed measurement. The burden of proof is on them: they are making a truly extraordinary claim, one that, if true, would entail revising all of physics from its very foundation.

When somebody sounds like a total fucking crackpot, they almost always are.

Of course not. The total momentum of the system stays zero.

When I was a kid, I tried to make a self-propelled car by putting magnets on the back and front bumpers of a toy car, reasoning that the front magnet would attract the back one, and therefore produce thrust. When I built it, I learned a valuable lesson: it doesn't work. Because the force pulling the back magnet forward is exactly counterbalanced by the force pulling the front magnet backward.

The EM drive is closely analagous to this idea. Except that they didn't figure out when they were eight that this will never work.

Well, the article says it, so it must be true.

If you're not throwing anything out of the back of the rocket, you're violating conservation of momentum.

Let's see: we can violate conservation of momentum by invoking some sort of vaguely defined quantum woo. Riiiight. Where do I send my check?

Continued car analogy: Mozilla, to this end, builds a car that shuts down when you try to drive it on a dirt road. Why would anybody want to buy a car that did that?

You'd think that they would take a hint from their declining usage, instead of doing crazier and crazier shit.