# Update on the EmDrive? Warp bubble speculated? **URL:** \ **Category:** Factual Questions\ **Created:** [April 27, 2015, 7:04am UTC](https://boards.straightdope.com/t/update-on-the-emdrive-warp-bubble-speculated/718623 "2015-04-27T07:04:56Z")\ **Posts on this page:** 20\ **Page:** 4
**Author:** ![Stranger\_On\_A\_Train](https://avatars.discourse-cdn.com/v4/letter/s/13edae/32.png) [@Stranger\_On\_A\_Train](https://boards.straightdope.com/u/Stranger_On_A_Train)\ **Post date:** [July 29, 2015, 2:48am UTC](https://boards.straightdope.com/t/update-on-the-emdrive-warp-bubble-speculated/718623/61 "2015-07-29T02:48:38Z")
> [@Chronos](#): > > I’ve often said that the great tragedy of Maxwell is that, of the two or three physicists in all of history who were greater than him, one happened to come along a mere few decades after him to overshadow him. I’m not sure that I’d cite Albert Einstein as even being his intellectual superior; Maxwell’s accomplishments across a variety of fields, both theoretical and practical, were extremely impressive, and the full extent of his work was not appreciated in his lifetime, or indeed, until the early 20th century. Another ten or twenty years might well have had him fleshing out statistical mechanics and developing basic relativity theory. His intuition about physical principles, combined with his extremely advanced grasp of mathematical methods that were not in wide use in his day show him as comparable to the greatest physicists of the succeeding generations; he was the first (and one of the very few) to appreciate Faraday’s description of magnetic lines of force as a permeating field, and although his full twenty equations for electrodynamics were long thought to be just confusing and incomplete, a more extensive reading of them shows very deep insight unequaled for the next twenty years. He was also a very charitable person and although not a great lectuer, an enthusiastic mentor to his students. I think the most comparable 20th century physicist is John Archibald Wheeler; a brilliant, creative thinker who just never quite achieved renown but fosted an entire generation of leading physicists. Stranger ---
**Author:** ![Lumpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lumpy/32/446_2.png) [@Lumpy](https://boards.straightdope.com/u/Lumpy)\ **Post date:** [July 29, 2015, 3:11am UTC](https://boards.straightdope.com/t/update-on-the-emdrive-warp-bubble-speculated/718623/62 "2015-07-29T03:11:08Z")
Didn’t someone post somewhere here that they repeated the experiment _with the power turned off_ and got the same measured thrust? ---
**Author:** ![Stranger\_On\_A\_Train](https://avatars.discourse-cdn.com/v4/letter/s/13edae/32.png) [@Stranger\_On\_A\_Train](https://boards.straightdope.com/u/Stranger_On_A_Train)\ **Post date:** [July 29, 2015, 3:25am UTC](https://boards.straightdope.com/t/update-on-the-emdrive-warp-bubble-speculated/718623/63 "2015-07-29T03:25:55Z")
In an earlier test (also without vacuum conditions because of their difficulty operating the amplifier in near vacuum conditions), yes. Which gives more question as to the precision and reliability of their test measurement setup. Stranger ---
**Author:** ![Terr](https://avatars.discourse-cdn.com/v4/letter/t/839c29/32.png) [@Terr](https://boards.straightdope.com/u/Terr)\ **Post date:** [July 29, 2015, 6:39pm UTC](https://boards.straightdope.com/t/update-on-the-emdrive-warp-bubble-speculated/718623/64 "2015-07-29T18:39:31Z")
> [@Stranger\_On\_A\_Train](#): > > In an earlier test (also without vacuum conditions because of their difficulty operating the amplifier in near vacuum conditions), yes. Which gives more question as to the precision and reliability of their test measurement setup. Apparently in this (German) test as well. > **[No, German Scientists Have Not Confirmed the “Impossible” EMDrive](https://gizmodo.com/no-german-scientists-have-not-confirmed-the-impossibl-1720573809)** > > Two German researchers claim they have produced measurable amounts of thrust using a copy of NASA’s controversial EMDrive. It’s a result that has many A much more balanced (well, a bit on the skeptic side) article on the latest German paper. ---
**Author:** ![SlackerInc](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/slackerinc/32/275_2.png) [@SlackerInc](https://boards.straightdope.com/u/SlackerInc)\ **Post date:** [July 29, 2015, 7:09pm UTC](https://boards.straightdope.com/t/update-on-the-emdrive-warp-bubble-speculated/718623/65 "2015-07-29T19:09:36Z")
If the measurements of thrust can be chalked up to MOE, wouldn’t they at least sometimes get a measurement of _negative_ thrust? ---
**Author:** ![Stranger\_On\_A\_Train](https://avatars.discourse-cdn.com/v4/letter/s/13edae/32.png) [@Stranger\_On\_A\_Train](https://boards.straightdope.com/u/Stranger_On_A_Train)\ **Post date:** [July 29, 2015, 8:59pm UTC](https://boards.straightdope.com/t/update-on-the-emdrive-warp-bubble-speculated/718623/66 "2015-07-29T20:59:28Z")
Since no detailed paper or open data review has been made available (as far as I’m aware) it is difficult to say how the reported thrust level was developed or validated. For instance, if they’re just taking an the measured force and subtracting a runnning average in a crude attempt to debias the data, the result would be essentially meaningless from a trendwise perspective in terms of filtering out all of the other potential contributions. Realistically, the only way to discern a real trend at this level is to attempt to fit the data to a prediction and see how well the regression fits the actual data, then convince yourself that you haven’t forced a fit to the data, i.e. that the prediciton is so flat or the distribution is so relaxed that any trend encompassed by the data would appear to fit. And even showing a positive trend isn’t sufficient to demonstrate that the proposed mechanism is what is causing the anomalous thrust; there are all nature of biases that could be introduced into the measurement that have to be accounted for before you could conclude that the data is genuinely demonstrating the proposed phenomenon. Stranger ---
**Author:** ![coremelt](https://avatars.discourse-cdn.com/v4/letter/c/4491bb/32.png) [@coremelt](https://boards.straightdope.com/u/coremelt)\ **Post date:** [November 14, 2015, 7:54am UTC](https://boards.straightdope.com/t/update-on-the-emdrive-warp-bubble-speculated/718623/67 "2015-11-14T07:54:39Z")
Haven’t seen the most recent news on here as yet. Tested and confirmed to be a real effect again by NASA Eagleworks just over a week ago: > **[NASA's 'Impossible' EmDrive Actually Works, New Tests Show | Digital Trends](https://www.digitaltrends.com/cool-tech/researchers-conduct-successful-new-tests-of-emdrive/)** > > Researchers at NASA's Eagleworks Lab just conducted careful testing of the controversial EmDrive and reported signs of thrust -- despite stricter testing procedures More testing to continue and apparently a peer reviewed paper to come soon. ---
**Author:** ![eburacum45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eburacum45/32/8690_2.png) [@eburacum45](https://boards.straightdope.com/u/eburacum45)\ **Post date:** [November 14, 2015, 6:41pm UTC](https://boards.straightdope.com/t/update-on-the-emdrive-warp-bubble-speculated/718623/68 "2015-11-14T18:41:56Z")
NASA Eagleworks is still only a very small subset of NASA, and I’d be happier if some other group with a slightly bigger budget were to have a crack at this. ---
**Author:** ![Grey](https://avatars.discourse-cdn.com/v4/letter/g/b782af/32.png) [@Grey](https://boards.straightdope.com/u/Grey)\ **Post date:** [November 15, 2015, 12:59pm UTC](https://boards.straightdope.com/t/update-on-the-emdrive-warp-bubble-speculated/718623/69 "2015-11-15T12:59:57Z")
**coremelt** , it is not tested and confirmed to be real. Did you even read your own cite? ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [November 15, 2015, 1:28pm UTC](https://boards.straightdope.com/t/update-on-the-emdrive-warp-bubble-speculated/718623/70 "2015-11-15T13:28:38Z")
They’ve ruled out one possible source of noise, but other possible sources of noise remain. And until all of those known sources of noise remain, that’s by far the explanation to be preferred (even after all the known sources are accounted for, unknown sources of noise are still a preferred option). Real science is a lot more slow and plodding than the media makes it out to be. ---
**Author:** ![Quartz](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/quartz/32/267_2.png) [@Quartz](https://boards.straightdope.com/u/Quartz)\ **Post date:** [November 15, 2015, 6:22pm UTC](https://boards.straightdope.com/t/update-on-the-emdrive-warp-bubble-speculated/718623/71 "2015-11-15T18:22:22Z")
Why is there a problem? They’re putting electrical energy in and getting thrust out, right? Does the alleged thrust violate E=mc2? ---
**Author:** ![leahcim](https://avatars.discourse-cdn.com/v4/letter/l/b4bc9f/32.png) [@leahcim](https://boards.straightdope.com/u/leahcim)\ **Post date:** [November 15, 2015, 9:15pm UTC](https://boards.straightdope.com/t/update-on-the-emdrive-warp-bubble-speculated/718623/72 "2015-11-15T21:15:45Z")
> [@Quartz](#): > > Why is there a problem? They’re putting electrical energy in and getting thrust out, right? Does the alleged thrust violate E=mc2? It isn’t proposed to violate conservation of _energy_, but conservation of _momentum_. In conventional rockets (or ion drives, or anything else of the like) the change in momentum of the rocket is exactly compensated for by the momentum in the opposite direction of whatever gets thrown out the back. EmDrive, if it works, would generate momentum without anything at all getting thrown out the back. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [November 15, 2015, 9:54pm UTC](https://boards.straightdope.com/t/update-on-the-emdrive-warp-bubble-speculated/718623/73 "2015-11-15T21:54:33Z")
> [@](#): > > Quoth me: > > And until all of those known sources of noise remain,… I mangled that sentence. That should be either “as long as any of those known sources remain…” or “until all of those known sources are ruled out…”. ---
**Author:** ![Dr.Strangelove](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dr.strangelove/32/6613_2.png) [@Dr.Strangelove](https://boards.straightdope.com/u/Dr.Strangelove)\ **Post date:** [November 15, 2015, 10:21pm UTC](https://boards.straightdope.com/t/update-on-the-emdrive-warp-bubble-speculated/718623/74 "2015-11-15T22:21:34Z")
> [@leahcim](#): > > It isn’t proposed to violate conservation of _energy_, but conservation of _momentum_. You can’t really separate the two, though. Photon drives exist–they don’t violate conservation of momentum. But the EmDrive can’t be a photon drive because if it were, it would violate conservation of energy (photon drives require much more energy for a given level of thrust). The other possibility is that is that it violates relativity. That is, it could work if the laws of physics are different across inertial reference frames. This is the “quantum foam” explanation, where the EmDrive is actually pushing on some sort of neo-ether. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [November 15, 2015, 10:36pm UTC](https://boards.straightdope.com/t/update-on-the-emdrive-warp-bubble-speculated/718623/75 "2015-11-15T22:36:48Z")
More precisely, one consequence of relativity is that conservation of energy implies conservation of momentum. If momentum isn’t conserved in one reference frame, and relativity is true, then there’s some other reference frame where energy isn’t conserved. ---
**Author:** ![Tabby\_Cat](https://avatars.discourse-cdn.com/v4/letter/t/6a8cbe/32.png) [@Tabby\_Cat](https://boards.straightdope.com/u/Tabby_Cat)\ **Post date:** [November 16, 2015, 12:38am UTC](https://boards.straightdope.com/t/update-on-the-emdrive-warp-bubble-speculated/718623/76 "2015-11-16T00:38:16Z")
Man you scientists are such killjoys. 😉 Seriously though, I for one thought that everything that would be relevant to “real life” and produce actual real world benefits had already been discovered, that my generation wouldn’t have the “computer age” moment where something that wasn’t possible before would suddenly be possible, that it was all incremental progress from now on. IF this thing is real, and reactionless thrust is a thing, and space travel becomes a thing, in my lifetime… I will be stoked. ---
**Author:** ![billfish678](https://avatars.discourse-cdn.com/v4/letter/b/7bcc69/32.png) [@billfish678](https://boards.straightdope.com/u/billfish678)\ **Post date:** [November 16, 2015, 12:40am UTC](https://boards.straightdope.com/t/update-on-the-emdrive-warp-bubble-speculated/718623/77 "2015-11-16T00:40:52Z")
I’m really outa my wheelhouse here but don’t some of the proponents of this sort of drive claim that it IS actually consistent with the math of relativity and the like? ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [November 16, 2015, 1:16am UTC](https://boards.straightdope.com/t/update-on-the-emdrive-warp-bubble-speculated/718623/78 "2015-11-16T01:16:05Z")
I’m sure some claim that, but that doesn’t make it so. ---
**Author:** ![billfish678](https://avatars.discourse-cdn.com/v4/letter/b/7bcc69/32.png) [@billfish678](https://boards.straightdope.com/u/billfish678)\ **Post date:** [November 16, 2015, 1:23am UTC](https://boards.straightdope.com/t/update-on-the-emdrive-warp-bubble-speculated/718623/79 "2015-11-16T01:23:46Z")
> [@Chronos](#): > > I’m sure some claim that, but that doesn’t make it so. Well, no duh 🙂 What I would like to see (not that I would understand it) is something like the following. Proponent: Equation X Equation Y Bunch more equations Equation Z Conclusion: This shit works Skeptic Physics dude (aka Chronos with evil Spock goatee): See, equation 1234x is where you screw the pooch on this. It won’t work. ---
**Author:** ![Francis\_Vaughan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/francis_vaughan/32/3093_2.png) [@Francis\_Vaughan](https://boards.straightdope.com/u/Francis_Vaughan)\ **Post date:** [November 16, 2015, 1:27am UTC](https://boards.straightdope.com/t/update-on-the-emdrive-warp-bubble-speculated/718623/80 "2015-11-16T01:27:58Z")
The popular press articles (which seem to be all we get on this) claim that there is mathematics, and that the maths has been checked over and found to be “OK”. Which is close to ridiculous for a number of reasons. One - if the maths is any good it should predict a precise thrust. Rather than looking for any thrust and trying to sort out if there is anything under the noise, there should be a clear prediction as to the numbers. Two. The machine contradicts relativity. What maths do they have that is “OK” and yet specifically contradicts accepted theory? [Previous page](https://boards.straightdope.com/t/update-on-the-emdrive-warp-bubble-speculated/718623.md?page=3) [Next page](https://boards.straightdope.com/t/update-on-the-emdrive-warp-bubble-speculated/718623.md?page=5)