It violates conservation of momentum (i.e. why solar sails work).
This is a pretty big problem with any evidence purporting that it does work because it requires a massive reinterpretation of our understanding of existing physical laws: i.e. it's mechanism of operation has to simplify to existing theory in such a way as to also explain why the effect is undetectable at the staggeringly high resolutions of measurements we've been making of other physical constants for decades now.
There is a big difference between "does violate" and "appears to violate".
The orbital motion of Mercury "violates" Newtonian gravity. There are other examples but I'm not trying to make a history lesson. I just want to point out, that science moves forward by impartial investigation of EVERYTHING. It's misguided to assume we know all and that there cannot be some thing we don't understand.
I'm as sceptical as anyone else about the EM Drive, but I want to understand "what the heck is going on with this thing that appears to move" more than I want to dismiss it as "not possible and obviously flawed because $ABC"
There are plenty of possible ways the drive could operate, and if it does work, it has the potential to significantly advance several fields of physics in a way no less valuable than other large expensive "hope this works" experimental physics experiments that no one is complaining about.
Mercury's motion does violate Newtonian gravity. General Relativity however simplifies to Newtonian gravity for various low-dimension applications though (i.e. an Apple falling from a tree, the orbit of the moon for most astronomical guidance purposes over that distance etc.)
In much the same way we don't account for the curvature of the Earth when building a house's foundations.
That's my point though: when you violate a fundamental physical law, it can't just be wrong. You have to somehow also account for why it doesn't happen all the time elsewhere (i.e. the effect is small to within experimental error over common measurement cases) and by necessity the new theory to explain it has to encompass the predictions of the old i.e. the benefit of Newtonian gravity was that it easily recovers the behaviour of nested epicycles of orbital motion (and made new predictions successfully where epicycles could not).
>"General Relativity however simplifies to Newtonian gravity"
I still don't see how this is possible. In GR gravity travels at the speed of light, in Newtonian mechanics it is instantaneous. I have been unable to find an acceptable explanation for how these two very different universes can be compatible.
As far as I can tell, the quote given by fapjacks is saying that the reactionless drive is impossible. Note that it is in a paragraph that begins "The other major kind of shonky coverage covers mythical propulsion..." (I had to look up 'shonky', but it is consistent with the above reading.)
Correct - Casey believes that the drive is impossible, given our understanding of physics. Given his background and credentials, I'm happy to defer to his opinion on the matter, over my own optimism.
Both he and I are firm believers of the scientific method though, so if researchers can show it experimentally then that's where the fun really begins. To my knowledge, the experiments until now have been fairly poor, with barely significant results (on the edge of noise).
But that's not what he's saying, now is it? He is dismissing it entirely as "impossible". Care to point me to the part of the scientific method which says "Feel free to dismiss outright things that don't make sense to you"?
Everything in science starts out impossible. It doesn't even get considered in science unless it has a chance of being impossible. Then it is up to the scientist to demonstrate that it is possible and explain how it is possible.
Edit:
The 1) demonstrate and 2) explain parts are critical and it's not science unless you have 1). Preferably 2) also. EM has neither to match the magnitude of the claims until they can push something across the solar system and back (such that loss of mass is ruled out and the propulsive effect is without a doubt not instrument error).
I think he's just expressing a healthy degree of skepticism, with a touch of hyperbole for flavour. He's likely just a bit sick of being asked his opinion on the drive until there's further experiments and research conducted on the matter.
I'm not dismissing your interest and excitement in the topic either. I'd love for it to be functional, and for us to learn new information on the way our universe works. The bar for entry is set particularly high on this, that's all :)
Unfortunately - even if you had some weird results that didn't fit the prevailing theorems, publishing would likely destroy your professional credibility. See: Fleischmann/Pons and their publications of abnormal results that others speculated might be related to cold fusion, the decades of slander and defamation of them as quacks (despite the fact that they themselves had not claimed anything of the sort), and their recent vindication.
> Perhaps most surprising is that, in the formative years of atomic science in the early 20th century, some scientists reported inexplicable experimental evidence of elemental transmutations. In the 1910s and 1920s, this research was reported in popular newspapers and magazines, and papers were published in the top scientific journals of the day, including Physical Review, Science and Nature. The experiments, using relatively simple, low-energy benchtop apparatus, did not use radioactive sources so the results defied prevailing theory. Several researchers independently detected the production of the gases helium-4, neon, argon, and an as-yet-unidentified element of mass-3, which we now identify as tritium. Two of these researchers were Nobel laureates.
To think that our current models adequately explain every phenomenon in the universe is truly the height of hubris. They can't even explain every phenomenon that has been observed on Planet Earth, let alone universally.
Of course extraordinary claims require extraordinary proof - but we do a tremendous disservice by disincentivizing scientists from ever reporting a novel finding that disagrees with the prevailing theories.
Sure, but it's not about whether or not the thing works. When I read his comment, I thought to myself, "What else has this guy missed in his work with such a dismissive attitude?" It's a messy mentality IMHO. And, you know, all seriousness aside, here he is saying the EmDrive is impossible, yet he's actually working on the hyperloop. Badum-psh!
I think, given the structure of phrase, we can assume some irony there - not only baseless dismissal.
EM drive remains pretty controversial, and does present significant problems with explanation, and as an extraordinary device requires extraordinary evidence. So it could be conceivable not to focus too deeply on a remark which isn't the main point of the article.
That, and that the amount of energy you put in to produce a unit of impulse with a theoretical EM drive is 10 times larger than the amount of energy required to produce that same impulse with a Hall effect thruster. For the journey to Mars that means the EM drive would tend to be much slower in practice even if it worked.
I'm pretty sure that fapjacks believes that the reactionless drive is possible, and all of the "No, this is silly" folks are just contrarian deniers who are holding back progress.
Woah there horsey, you're basically sticking anyone that thinks reactionless drive might be possible into the crazy conspiracy theory category, and there are plenty of people that are interested in honest reproducible research on the topic.
Just blanket suggesting that it is in no way possible without any evidence is no better than blanket suggesting it is possible without any evidence (well, it's a little better, since the laws of physics are on your side, but...)
Right. That's the spirit of my original comment. There are obviously people here with some serious investment in their own educations and egos that think this thing is impossible. Yet, here we are, peer-reviewed evidence[0] mounting.
