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[Reelya]

Here's a typically scientifically illiterate news report about the Em-Drive.
http://www.news.com.au/technology/science/space/impossible-em-drive-engine-produces-thrust-from-nothing-and-science-cant-explain-why/news-story/4f58c35ec63e42d77e7fe443af1f47d6

IT’s impossible. But science appears to say it’s happening. A prototype space engine seems to be producing energy from nothing. And it’s just passed peer review.

The reactionless thruster was met with a surge of excitement — and scepticism — when reports of its science-fiction sounding ability to pull fuel out of the void of space itself emerged in 2001.

...

SOMETHING FROM NOTHING

The EM Drive is essentially a chamber with a hole at one end with microwaves bouncing around inside.

There is no fuel supplied.

But, when turned on, the drive generates thrust.

Worse, it violates some of the most fundamental laws of physics that our understanding of the universe — and all of our technology — is built upon.

Or not.

“It’s looking stronger,” Dr Neumann says. “But it’s still breaking the law of conservation of momentum — which is something we’d really like to keep as it’s the basis of some really important bits of science and technology.”

What should make the engine impossible is Newton’s Third Law: “For every action, there is an equal and opposite reaction”. Put simply, something doesn’t move unless an outside force pushes it.

This is why engines need fuel. The fuel contains energy.

The EM Drive carries no fuel. So there is no energy to release.

This makes me really angry that such illiterate people write articles.

[Dozebôm Lolumzalìs]

Ugh, the "nothing moves without a force" law is the First!

[MetalSlimeHunt]

Funnily enough, Scott Manley's video on the EM Drive does discuss how one of the alternate explanations for it doesn't violate the third law, but does violate the first.

[Max™]

Less excitingly but more plausibly, we know the Casimir effect is a thing, wrongly and horribly put, you could sorta think of the vacuum as being fizzy, two plates a small distance apart prevent the fizz from getting between them, and as you move them closer to exclude smaller and smaller scale fizziness you observe an ever greater force between the plates.

Mathematically it works out in a way which doesn't really fit the metaphor, but it's close enough for nuclear hand grenades I guess.

If the EM Drive is doing anything new and exciting it is probably not an "omigawsh we gotta throw away physics" type of thing, and more along the lines of "assume the far side of the universe is an infinite plate, and our drive is the other plate" I think. Without a way to get the sexy Casimir-Polder forces from two plates with a tiny gap, you're left pushing against the fizz to eke out 1.2 mN/kW or so apparently.

Super neat for long range probes, could probably be handy for certain station keeping roles even?

The uses as a drive aren't as interesting as the different things you might be able to do if it turns out we can alter the geometry completely from the tested design, if it's actually doing what it looks like then the big takeaway might not end up being "reactionless drive" at all, it might be "fuckin' wormholes yo" eventually.

[Shadowlord]

Does the paper actually say that the emdrive is producing negative energy, or are you just using your ~imagination~?

[Il Palazzo]

Don't go building your spaceships yet. The paper might have been published, but it doesn't mean it's meaningful.

What I've seen so far is media jizzing all over the place, fanboys building galactic empires, and the few scientists who bothered to read it scathingly criticizing the methods used in the paper.

In the end, any publication has the goal of convincing other people. This seems to be aimed more at convincing the press rather than their peers.


I actually disagree with MSH as to the nature of this development - this doesn't look like the FTL neutrino case, since those people used everything at their disposal to make sure that the null hypothesis doesn't fit the data before going public. It was as water-tight as they could make it. Here, we've got people using sloppy analysis to push their preconceptions - similar to what you get in cosmology from time to time, with various papers seeing structure where there is none. Or what you get with the cold fusion crowd.

My prediction for the future is: a number of rebuttals will get published, somebody will use the paper to get grant money, and a number of EM drive building scams will pop up.

[TempAcc]

Several possible situations that could have caused a false reading have been pointed out in the peer reviews, though. Since this is just a paper review, they didn't go out and build their own versions of the drive (the drive itself seems simple enough to build, the problem is having the entire array of measuring equipment at your disposal, like eagleworks does, being a NASA branch and all that, which isn't exactly something anyone can have), they just evaluated how the experiment was carried out within the limits of the content of the paper.

[TempAcc]

Woops, I got confused, actualy. The possible errors pointed out in the paper are actualy by the authors, including justifications pointing out that said possible errors have been accounted for.

[Dozebôm Lolumzalìs]

If the EM Drive is doing anything new and exciting it is probably not an "omigawsh we gotta throw away physics" type of thing

It never is. That kind of paradigm shift isn't common. Take relativity, ferex - Newtonian mechanics still worked, as long as gravity and speed were negligible. Science is very accurate at describing the everyday realities that we are used to - that will never be thrown away. We won't have a "shit, the Earth isn't flat after all" moment, ever. What we will have is a "whoa, if we look at the small scale, physics is completely different and weird" moment, at most, or a "whoa, the value of this force is 0.999999999999999 of what it should be, because of the X Effect" moment.

We could disprove the more speculative theories, like string theory. But that is quite different from "physics" as a whole.

TL;DR: Science builds on top of itself. The foundation will never be thrown away; some speculative scaffolding on the top may. Also, I'm preaching to the choir and tilting at windmills.

[Max™]

Does the paper actually say that the emdrive is producing negative energy, or are you just using your ~imagination~?

Note that I said if it works as they posit, which--according to the general description of these that I've seen in that paper and elsewhere--hinges upon there being virtual particles in the vacuum that you can interact with in certain ways to generate thrust and so forth.

IF that is the case, all sorts of fuckery would be implied, this is by no means a certainty, and indeed attempting to construct different devices using the claimed effect would probably be informative.

[x2yzh9]

My question here is how is it circumventing the law of conservation of momentum, if in fact the fuel source in and of itself is electromagnetic microwaves? That's a force in physics in its own right. Or am I wrong here?

[MetalSlimeHunt]

TL;DR: Science builds on top of itself. The foundation will never be thrown away; some speculative scaffolding on the top may. Also, I'm preaching to the choir and tilting at windmills.

This I do not agree with. While the foundations of physics will never be suddenly eliminated, our advancements are not limited to the speculative and uncertain. The issue is that we do not necessarily know that our understanding of the "foundation" is complete, and in fact it probably isn't. Higgs boson, Special relativity, dark matter, how gravity functions, etc. The context of these discoveries can alter our context all the way down to the most basic assumptions, and change all of them as a result.

For example, if the EM Drive were to function properly, you might end up with "For every action there is an equal and opposite reaction, except for resonance carried through radiation of energy". Which would fundamentally alter damn near everything else that follows it, but in a way we were able to miss up until now due to existing presumption and lack of good experiments because of Earth's gravity.

Not that I have changed my bet that the EM Drive won't work.

[wierd]

The virtual particle theory is also implicated in other theoretical phenomena, like hawking radiation, where the antimassed virtual particle falls into the event horizon, and the massed one does not, resulting in mass zipping away from the black hole's horizon in the form of radiation, while the mass of the singularity is reduced, as it absorbs the antimass of the particles streaming in, causing annihilation, and turning the mass into spacetime to satisfy the field equations.

Virtual photons are also demonstrated and used regularly by humans. Near field communication between cellphones and credit cards makes aggressive use of virtual photons which make up the bulk of the EM near field.

The secret sauce I am seeing here is the de broglie-bohm interpretation of physics being used instead of Copenhagen. Bohm says that particles are always particles, but that they are constrained by the pilot wave they ride on. (A bit like a surfer rides a wave, and can only ride on certain parts of a wave) the pilot wave can experience constructive and deconstructive interference, and this impacts the trajectories of particles riding on them.

It is that secret sauce that would permit manipulation of the pilot wave to permit only antimassed virtual particles to ride in one place, and massed ones in another, to create concentrated populations. That would satisfy the negative mass requirements for the alcubierre metric to be created, and thus create warp drive.

That's a big if though.  Physics likes Copenhagen for a reason, and I expect that the universe would have to pry it from their cold dead hands before it loses favor.


Time will tell.

[TempAcc]

Having physics being thrown around and changed is relatively normal, just look at the whole conundrum happening atm with dark energy and etc. The problem is that the EM drive violates some of the very known basics of physics as we know them. So it either works and doesn't violate physics because of some sort of yet undetected phenomena, or we were terribly wrong from the beginning and yet have been able to create consistent models off said mistakes, somehow.

Both are unlikely to happen, so its likely that the drive is simply doing something other than what people think its doing, something that doesn't actualy violate known physics, but just seems to do that.

But there's yet one phenomena unaccounted for in the paper: its 2016

[Max™]

Note that I wasn't questioning virtual particles, just dubious at the idea that we can encourage them to play nicely for effects like the EM Drive, but cautiously excited at the implications of being able to dig our fingers into the guts of the universe and root around like that.