What's going to happen with this newfangled EM drive?

New article today: http://www.sciencealert.com/independent-scientists-confirm-that-the-impossible-em-drive-produces-thrust

Basically it’s saying another knowledgeable person has surprised himself by finding the thing actually works, for reasons he can’t discern.

Still no peer reviewed research, and there still exists more to be done, according to the article, to rule out side effects from things not controlled for.

But what’s the big picture here? Is this something that should be laughed off or is it really possible somebody is on to something here?

It seems like the thing keeps surprising people by continuing to work as predicted by the apparently loony theory of its original inventor.

I’m basically awaiting peer reviewed testing. I seem to recall that there were some questions about the vacuum testing, especially, being flawed. Basically, if this thing actually works as asserted it would IIRC re-write Newton’s 3rd law, as well as the conservation of momentum, so that’s going to take some serious independent testing by a lot of folks before it becomes accepted that it’s doing what people say it’s doing. Part of the problem has been that it hasn’t been taken seriously by the scientific community because it breaks fairly fundamental laws of physics, which sets off the nutter alarm in most main stream scientists. But if it actually works AND can be independently verified by multiple labs in peer reviewed journals then it could really be something new.

Personally, I’m not holding my breath, but could be a major breakthrough if it pans out.

Even if there is no reaction mass photons carry momentum. I don’t know how much thrust they claim but it sounds a little like a solar sail with its own light source.

Harold White describes the drive as being like a propeller, but is pressing against the virtual particles of space. That is seriously weird, but doesn’t seem like it would re-write Newton. From what I understand it doesn’t really explain the efficiency, either.

Long thread at emdrive.wiki where this drive is debated.

Wolf: Probe now closing at 15.3 meters per second. Collision course.

Data: Captain, sensors are reading no particulate emissions or subspace field distortions.

Picard: Then how is it able to move?

Data: Method of propulsion is unknown, sir.

-The Nth Degree

Follow the money, after all, no bucks no buck rogers. You can put this thing into orbit within a few months, and let the science follow later, if it moves beyond the starting line and goes where no man has gone before.

Until someone ponys up the cash, I’d say its got limited appeal.

Now if a bunch of people crowd fund it for shits and giggles, well thats just ducky.


reading the article update the data appears to be flawed.

Well, as far as I can tell, there’s really no theory there to speak off, apart from some handwaving claim in the direction of ‘virtual particles’ to get around the apparently blatant violation of conservation of momentum. The problem is that this can’t work: the QFT vacuum carries no momentum, so if you start out with the ship stationary in a vacuum, and end up with the ship moving, you either still have some violation of conservation of momentum, or the QFT can’t be in the vacuum state any longer. In the latter case, you’d have produced a bunch of particle pairs, and then simply accelerated them—which is basically possible, but is far less inefficient than even using a photon rocket, which yields thrusts orders of magnitude less than that of the EM-drive purportedly produces.

So it seems that whichever way we slice it, we loose conservation of momentum if this thing works. One might say, well, then so much for conservation of momentum, but the problem is that ultimately, COM really just amounts to the statement ‘physics over here works like physics over there’, that is, how physical processes occur is independent of where they are performed—physics is invariant under arbitrary spatial transformation. Noether’s theorem then tells us that with any such symmetry, we get a conserved quantity, and in the case of spatial translations, that’s momentum (in the case of translations in time, i.e. ‘physics works the same today as it does tomorrow’, for instance, the conserved quantity is energy; of course, in special relativity, space and time, and hence, momentum and energy, are deeply connected, so if we loose one, and SR is right, we’ll also loose the other).

All in all, while it’s of course the case that any scientific tenet must be open to experimental revision, given the fact that pretty much the entire well-tested and intricately connected edifice of physical science would come tumbling down if you’d unravel that particular piece of string, the hardness of measuring very small forces, and the amount of evidence available today, I feel pretty comfortable in asserting that the thing probably does not work as advertised. The evidence for FTL neutrinos at Gran Sasso was much more persuasive, given that an entire team of highly trained experts couldn’t locate the fault with their own experiment, while here, we have scattered reports trying to replicate somebody else’s work, and yet, scepticism also was the right reaction then, even though the implications would probably have not nearly been as far-reaching.

Of course, it could always be the case that something unknown is doing we don’t know what, and if that could indeed be substantiated, I’ll be the first to get excited; but before that happens, a lot of research would have to be done.

How much force has the latest experiment reported? The earlier one was 50 micronewtons, which to put it in terms we Americans can relate to, about one ten-thousandth of an ounce of force.

So what would you bet on, that an outsider lone wolf has overturned basic laws of physics that we thought were solid, or that there is a small experimental error somewhere that no one has yet thought of the source?

It’s a fun puzzle, but I’m not betting on the result being real.

It reminds me of the results from a couple of years ago, where researchers reported something (photons?) going faster than the speed of light. That was a fun puzzle too, but the researchers there handled it properly: they reported the results, not making any wild claims, and invited the rest of the community to help find the error. Which they did.


and who could forget cold fusion before that.

History is full of ground breaking discoveries that turned out to be technical errors.

Even so -

The most exciting phrase to hear in science, the one that heralds new discoveries, is not “Eureka” but “That’s funny…” - Isaac Asimov.

Steven Novella:

Despite Headlines, The EM Drive is Still Bullshit

Bumping this thread because another test seems to show that the drive works.

Really weird, if I’m understanding it right.