This is an archive of past discussions. Do not edit the contents of this page. If you wish to start a new discussion or revive an old one, please do so on the current talk page. |
Archive 1 | Archive 2 | Archive 3 | Archive 4 | Archive 5 | Archive 6 | → | Archive 9 |
We have:
While this may be strictly true, it is equally true that if pigs could fly it would have important implications for aerospace. Since the consensus is that have not been found to work as claimed, and are extremely unlikely to be found to work as claimed, this speculative marketing claim does, IMO, not belong in the lede. Guy ( Help!) 09:51, 24 March 2016 (UTC)
This has already gone on rather long, the statement is backed up by a reliable source and therefore is not original research, and helps the reader establish context for why people care about the device. There isn't more for me to say really. Insert CleverPhrase Here 02:01, 25 March 2016 (UTC)
I edited the sentence again to increase clarity and better reflect the sources and to address any potential
WP:CRYSTAL issue.
Insert
CleverPhrase
Here
02:13, 25 March 2016 (UTC)
This sentence:
The claims of proponents, especially in respect of independent validation, are disputed.
This is the final part of the lede and is rather vague. I'm not sure exactly what point it is trying to impress upon the reader, but I feel it could do it with more precision. What claims, how are they disputed, and what independent validation is claimed/disputed? Any suggestions? Insert CleverPhrase Here 05:36, 24 March 2016 (UTC)
A few new sources that mention or are about the em drive that I found having a quick scan of recent news articles. Some of these might be useful in editing the article, particularly the Forbes article and the Next Big Future article.
InsertCleverPhraseHere InsertTalkHere 04:37, 15 February 2016 (UTC)
I have to admit this edit summary [1] justifying why we should say it's been published in "journals" (plural), even though it's only been published in one journal, made me smile. Any volunteers to rewrite this article? Note that, if time is an issue, "Deleting every single statement that doesn't have an inline cite with solid WP:WEIGHT" is a perfectly valid way to conduct a rewrite for an article such as this. Rolf H Nelson ( talk) 07:11, 8 February 2016 (UTC)
One initial reason for believing the article is NPOV is that this I disagree with the reversion [3]. I believe the scientific consensus is that the anomalous results are extremely likely to be experimental error. In addition, I believe that all weakly-cited information should be removed; an initial removal of things that are obviously weakly cited and controversial would be a helpful first step. Rolf H Nelson ( talk) 01:43, 9 February 2016 (UTC)
InsertCleverPhraseHere: [4] "section does not belong in the 'history' section as it is simply a collection of claims by the inventor in his patent, belongs in the 'emdirve' section instead". I was totally with you until the comma. If you're going to illogically block its removal, I think the thing to do is to pause my edits and see if someone steps forward within the next month to rewrite. If they don't maybe I'll go ahead and rewrite it myself, using appropriate dispute resolution methods if it's tendetiously blocked. Rolf H Nelson ( talk) 03:46, 16 February 2016 (UTC)
I've removed the tag since I'm satisfied with the current version. Rolf H Nelson ( talk) 04:24, 19 February 2016 (UTC)
I removed the 'too technical' warning from the top of the page, as the page is almost unrecognisable from the July 10th version when the warning was last updated. See the following diffs that show the changes between that version and the current one [5]. If anyone thinks the article is still too technical for most readers, please specify here which sections require cleanup prior to reinstating the warning box. Thanks. InsertCleverPhraseHere InsertTalkHere 03:29, 23 January 2016 (UTC)
The result of the move request was: not moved. There is a consensus against renaming this article "Asymmetric cavity drive". However, some participants were happy with the nominator's alternate title, "Radio frequency resonant cavity thruster", and I would recommend starting a new RM to see if there is a consensus to move to that title. Sorry if that feels overly bureaucratic, but in my experience starting a new discussion for the variant is often the best way to get a clear outcome that isn't muddied by the previous proposed title. Jenks24 ( talk) 06:35, 16 November 2015 (UTC)
RF resonant cavity thruster → ? – My proposal is to rename the article Asymmetric cavity drive or Radio frequency resonant cavity thruster. Rationale for Asymmetric cavity drive can be found in section above by Tokamac. Rationale for Radio frequency rather than RF is that it makes more sense to the reader.
Brian Everlasting (
talk)
02:59, 8 November 2015 (UTC)
I see that KRAPENHOEFFER has linked this article to Pseudophysics, and proposes a major rewrite.
I agree with the assessment of this article as Pseudophysics, of the 4 reasons for considering an article as pseudophysics on that page, the second reason stated on the article in question seems appropriate. I'm disappointed that you didn't bring up the need for a distinction between PS and QS in your recent post on the Fringe noticeboard, as it was, all people said was that it was fringe, which is obvious, it was already listed as a fringe article. I don't agree that this subject is unambiguously pseudoscience, as it seems somewhere between that and questionable science.
Be careful of pushing the 'it's impossible' viewpoint too strongly, as you seem to have a very strong viewpoint on this subject. Please maintain NPOV and realise that as a fringe article, while we should make it clear that while wikipedia supports the mainstream viewpoint, there must be room to discuss and present fringe viewpoints fully. I also maintain that at least one of the fringe theories discussed in the article claims not to break conservation of momentum. This theory isn't universally accepted of course, but it does leave you with a little less room to stand on in terms of claiming that it definitely breaks the law of conservation. Please propose and discuss any major Edit Proposals on the talk page before going ahead with them. InsertCleverPhraseHere InsertTalkHere 20:14, 19 October 2015 (UTC)
1. It is worrisome for now that the main features of the EmDrive: its asymmetry and the fact the asymmetric cavity is specifically shaped as a frustum for most test articles, are not explicated in the main section of the article but appear later in the text as almost side notes. This should be addressed. The asymmetry is so important that the title of the article should perhaps be asymmetric cavity thruster.
2. As already explained elsewhere, 'cavities are resonant in principle, rendering the name "resonant cavity" tautologous'.
3. RF should also be dropped, as RF is generally said to be comprised between 1 and 3 GHz, but the EmDrive could theoretically scale to work below and above those frequencies.
4. Also already explained elsewhere: "drive" is a little better than "thruster" since we're still not sure it's pushing rather than pulling.
5. For the above reasons the name of the article should perhaps be asymmetric cavity drive — Tokamac ( talk) 20:18, 22 July 2015 (UTC)
A while back, I decided to be bold, and re-wrote the lede to use stronger language to reflect the scientific consensus that this thing doesn't work. I see that it has been changed back to the weaker language. My proposal is to reword "Their design principles seem to be not scientific, because they violate the fundamental law of momentum conservation." in the lede to the more accurate "Their design principles are rejected by mainstream science, because they violate the fundamental law of momentum conservation."
Without reliable sources indicating otherwise, failing to include the stronger language gives WP:UNDUE weight to a fringe position. If there aren't any objections, I will make the edit myself in 24 hours. -- KRAPENHOEFFER! TALK 20:56, 15 October 2015 (UTC)
This line in the lede:
A small thrust has also been observed in devices deliberately built to not produce thrust.
is disingenuous at worst, misleading to readers at best. The test in question was a control, and was used to determine if the Cannae drive creators' theory of radial slots being necessary was correct. it wants 'designed not to produce thrust' it was 'designed to test if radial slots are necessary for thrust production'. In science you might design something so that under a certain persons theory (if correct) it would not produce thrust, but you aren't making a device to specifically not produce thrust, you are doing it to test that theory. This test was a SUCCESS in testing the canna drive radial slot theory, (disproving it in favour of the competing theory that radial slots were not necessary). When this is taken into context, the line that has been inserted into the lede is very misleading, and instead suggests that there was some error in measurement, or that thrust measurements were badly made. Im reverting the edit again. InsertCleverPhraseHere InsertTalkHere 00:27, 14 October 2015 (UTC)
changed to:
A small thrust was also observed in a null test with a device lacking radial slots, indicating that the slots are not necessary for anomalous thrust production.
This both indicates that it was a null test, and makes clear what was accomplished by said null test. InsertCleverPhraseHere InsertTalkHere
I added quiet a lot to the history section which seemed to be missing a context for general public readers. Isaac Newton as reinterpreted after General Relativity was presented as a way to show that the RF resonant cavity thrusters are attempting to alter a perception that has survived several hundred years of scrutiny.
The intervening history was discussed to show that there are long standing theories and proofs about how thrust can be generated without violating conservation of momentum.
Some other writer has removed one sentence about gravity waves about which much is researched and published, but does not have a consensus and is not essential for the purpose of history.
I deleted one other sentence about interference patterns canceling Poynting vectors found objectional to one of the editors as too technical to convey a meaning.
All of the other editors are welcome to improve on the history section, hopefully to show there is a robust science of mechanics since Galileo and dynamics since Newton that Einstein didn't overturn, and many theories about thrust force have been created and tested since then without violating a long standing principle.
I'm not a fan of RF resonant cavity thrusters, but feel every topic gets a fair chance, and there are new things waiting to be discovered and published that haven't found a place yet in Wikipedia guiding principles. In that regard I have left out some of the recent history that is most contentious and is best contained in private correspondence.
As always thanks to the people who helped so far. Astrojed ( talk) 17:39, 15 September 2015 (UTC)
This page is not a forum for general discussion about EmDrive/Archive 4. Any such comments may be removed or refactored. Please limit discussion to improvement of this page. You may wish to ask factual questions about EmDrive/Archive 4 at the Reference desk. |
Using numbers representing the thrust of the EM generator shown here in Wikipedia and using the aid of superconductivity, the drive could be used on the perimeter of a wheel which drives an electrical generator which will then give vast amounts of power above what is needed to maintain the thrust. This will use one moving part plus electronics and cooling.
Development for domestic power generation will give the world a new standard of living with clean air and little need for energy from coal and petroleum.
Richard Smith — Preceding unsigned comment added by Power102 ( talk • contribs) 20:52, 4 September 2014 (UTC)
The power input for the Emdrive is electricity. It cannot be made into a perpetual motion machine because the output force could not produce enough electrical energy for self perpetuation. It's best use presently appears to be as a better propulsion system than ion drive since it does not require fuel; it can generate electricity for itself through solar cells. It also seems to be more efficient than a solar sail for acceleration. Of course all experiments so far have been small-scaled and tentative. Its biggest potential for the next century might be as a much more efficient lift-to-orbit system/ engine, and for solar system touring crafts, heavy freighters, and landing craft. This would involve large Rocket sized devices but with very small acceleration, noise, and G forces. Maybe a perfect low-cost passenger craft to the moon, mars, Jupiter's moons, and the asteroid belt, mining etc.. Much larger prototypes need to be built involving superconductive, and supercooled electrical and internal components, to show the proof-of-concept for multi-flight heavy-lift devices -- possibly at production costs as low as large aircraft. It has also been mentioned that time efficiency to get started would require rocket fuel once orbital heights have been reached. Forrestnoble ( talk) 04:51, 10 September 2014 (UTC)
...addressing the question of whether an EmDrive can drive an electrical generatoris off-topic for this talk page. It has nothing to do with the Wikipedia article. This whole thread has been purely speculative, so nothing can have been "hijacked". __ E L A Q U E A T E 18:57, 10 September 2014 (UTC)
We really should avoid presenting the working of these devices as implicit fact in the intro. Whether they work as claimed or not, their operation is still being investigated, and the jury is still out. No-one (except perhaps their inventors) would be more excited if they work than me (new physics! flying cars! etc.!) but we need to be very cautious in our reporting. The null hypothesis must still be that they don't work, until iron-clad experimental evidence is available to answer the question one way or another. -- The Anome ( talk) 10:05, 30 July 2015 (UTC)
I've now changed the intro paragraph to read like this:
RF resonant cavity thrusters are a proposed new type of electromagnetic thruster. Unlike conventional electric thrusters, they not designed to use any form of reaction mass, nor to emit any directional radiation. They have not as yet been proven to work as claimed, nor are their design principles accepted by mainstream science, which predicts that they should be unable to produce thrust. However, small thrust effects have been measured in some experiments using prototype devices, and research is in progress to see if these effects are caused by some as yet unknown phenomenon, or artifacts due to experimental error.
I hope this combines necessary skepticism with fairness to those involved. The experiments do show measurable effects, theory predicts that they must be experimental error, and experience shows that in cases like this theory is almost certainly right -- but the preliminary results are intriguing enough that it's worth keeping on researching, just in case.
And, yes, cold fusion does come to mind as a very similar situation: impossible in theory, tantalizing experimental results suggesting theory might be wrong (but with a small effect size that is hard to measure reproduceably), massively exciting consequences if real. Even though I expect the story is likely to have a similar ending to the cold fusion work a decade or so ago, I think this is currently a valid example of fringe physics, and I've added this article to Category:Fringe physics to reflect that. -- The Anome ( talk) 10:59, 31 July 2015 (UTC)
Also: I believe most of Quantum vacuum thruster should really be split off and merged into this article, as it overlaps this topic almost completely. -- The Anome ( talk) 11:19, 31 July 2015 (UTC)
The table at the top says "violates conservation of momentum" as if that was an established fact. It should say something like "Claimed by some critics to violate conservation of momentum", or "apparently violates conservation of momentum". Until we know how it works, if it does work, you can't say it violates COM.
For now all we have is the experimental data, which suggests a thrust of micronewtons, in a stationary apparatus (we don't have any kind of a spaceship drive yet).
This does appear to violate COM - but then - new physics can do that - as happened historically with beta decay before the discovery of the neutrino.
The inventors of the drive and the experimenters - neither of them say that it is a reactionless drive. And the io9 article you link to refers to an opinion of a single scientist. That is not the same as a consensus, and there seems to be a diversity of views here amongst scientists.
The theory section also should probably be filled out with more theories. For instance in the Eagleworks presentation available on video (if that is an acceptable source for the article) they gave several ideas of how it might work. Including for instance, the idea of a mild space warp (their most "out there" idea which got a lot of publicity) which would work similarly to the Alcubierre drive - and of some new kind of very weakly interacting particle to carry the momentum - and talked about ways they could test for these possibilities with experiments.
Robert Walker ( talk) 14:06, 1 August 2015 (UTC)
One suggestion, what about dividing up the theory section, and moving this block down there and using it to flag just the section on Roger Shawyer's theories? And then in that section, also give his own explanation of why he thinks it doesn't violate COM, and say why others find his explanation not convincing. And similarly label any other theories that most people think would violate COM / COE. Robert Walker ( talk) 12:57, 4 August 2015 (UTC)
I think also that this should be changed, as in accurate
" particularly because there are no compelling explanations for the apparent violation of the law of conservation of momentum,[9] and claims of such a surprising result would need especially thorough efforts to rule out possible sources of error." (end of lede)
It is sourced to a single io9 article, which in turn does voice the opinion of a scientist - but one scientist saying something doesn't make it a consensus, and it is not even a peer reviewed paper but just an interview quote. The main problem is not the apparent violation of COM, you can say that of course, but when it goes on to say "claims of such a surprising result". That suggests that the experiments if they verified the effect would also prove a failure of conservation of momentum. Which is untrue. They wouldn't prove that, any more than the experiments on beta decay proved failure of COM / COE. Just prove an apparent violation which would lead physicists to scratch their heads and try to find a new physical theory or new particles to explain it. Only a perpetual motion machine, or an infinite energy source or similar would immediately prove a failure of COM / COE with no hope of rescuing the laws with new physics. Robert Walker ( talk) 13:03, 4 August 2015 (UTC)
BTW I'm author of an article on the EM drive which may be a useful source of citations. I'm not sure how many of my citations would pass muster as citations on wikipedia, e.g. can you cite the Eagleworks video?? Or forum posts by members of the Eagleworks team and other scientists? And some of it would surely count as original research also, and it is not peer reviewed, is just a news story, but it does have a few links that may be useful. Suggestion: The EM Drive Is Getting The Appropriate Level Of Attention From The Science Community Robert Walker ( talk) 13:07, 4 August 2015 (UTC)
Anyway to explain this without violating the laws of physics. 176.252.136.138 ( talk) 17:50, 31 August 2015 (UTC)
Also it is worth mentioning that all the intermediate steps ie superconducting cavities, RF feedback at resonance are well established engineering principles. The problem is that because teams are reluctant to report null results the scientific community do not take them seriously.
I've actually run into a variant of this with my HTSC research, noticed significant resistance drops in heavy metal doped pyrolytic graphite but no journal will even look at my draft because it is not from an established research institution. — Preceding unsigned comment added by 185.3.100.53 ( talk) 10:37, 8 September 2015 (UTC)
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Removed from the article:
The only peer-reviewed article about these drives that I know of is Shawyer's recent article in Acta. Which doesn't show any positive thrust; it is a hypothetical and theoretical paper (with extraordinarily optimistic predictions). – SJ + 01:51, 8 September 2015 (UTC)
The overwhelming academic consensus is that the subject of the article is pseudoscientific. In this regards, the article clearly lends the subject undue credence, although there has certainly been a lot of hype and speculation in the media. I appreciate any help editing this to be move NPOV and I have requested the help of an expert in physics on their page. 139.222.202.221 ( talk) 11:10, 31 August 2016 (UTC)
I undid the revisions to the lede by IP above. Contrary of his claim to remove POV, their changes essentially changed the lede to be from only one POV. Furthermore, many of the changes recreated many of the older problems with the lede that were corrected via extensive talk page discussions and compromises. Insert CleverPhrase Here 21:31, 31 August 2016 (UTC)
This is an archive of past discussions. Do not edit the contents of this page. If you wish to start a new discussion or revive an old one, please do so on the current talk page. |
Archive 1 | Archive 2 | Archive 3 | Archive 4 | Archive 5 | Archive 6 | → | Archive 9 |
We have:
While this may be strictly true, it is equally true that if pigs could fly it would have important implications for aerospace. Since the consensus is that have not been found to work as claimed, and are extremely unlikely to be found to work as claimed, this speculative marketing claim does, IMO, not belong in the lede. Guy ( Help!) 09:51, 24 March 2016 (UTC)
This has already gone on rather long, the statement is backed up by a reliable source and therefore is not original research, and helps the reader establish context for why people care about the device. There isn't more for me to say really. Insert CleverPhrase Here 02:01, 25 March 2016 (UTC)
I edited the sentence again to increase clarity and better reflect the sources and to address any potential
WP:CRYSTAL issue.
Insert
CleverPhrase
Here
02:13, 25 March 2016 (UTC)
This sentence:
The claims of proponents, especially in respect of independent validation, are disputed.
This is the final part of the lede and is rather vague. I'm not sure exactly what point it is trying to impress upon the reader, but I feel it could do it with more precision. What claims, how are they disputed, and what independent validation is claimed/disputed? Any suggestions? Insert CleverPhrase Here 05:36, 24 March 2016 (UTC)
A few new sources that mention or are about the em drive that I found having a quick scan of recent news articles. Some of these might be useful in editing the article, particularly the Forbes article and the Next Big Future article.
InsertCleverPhraseHere InsertTalkHere 04:37, 15 February 2016 (UTC)
I have to admit this edit summary [1] justifying why we should say it's been published in "journals" (plural), even though it's only been published in one journal, made me smile. Any volunteers to rewrite this article? Note that, if time is an issue, "Deleting every single statement that doesn't have an inline cite with solid WP:WEIGHT" is a perfectly valid way to conduct a rewrite for an article such as this. Rolf H Nelson ( talk) 07:11, 8 February 2016 (UTC)
One initial reason for believing the article is NPOV is that this I disagree with the reversion [3]. I believe the scientific consensus is that the anomalous results are extremely likely to be experimental error. In addition, I believe that all weakly-cited information should be removed; an initial removal of things that are obviously weakly cited and controversial would be a helpful first step. Rolf H Nelson ( talk) 01:43, 9 February 2016 (UTC)
InsertCleverPhraseHere: [4] "section does not belong in the 'history' section as it is simply a collection of claims by the inventor in his patent, belongs in the 'emdirve' section instead". I was totally with you until the comma. If you're going to illogically block its removal, I think the thing to do is to pause my edits and see if someone steps forward within the next month to rewrite. If they don't maybe I'll go ahead and rewrite it myself, using appropriate dispute resolution methods if it's tendetiously blocked. Rolf H Nelson ( talk) 03:46, 16 February 2016 (UTC)
I've removed the tag since I'm satisfied with the current version. Rolf H Nelson ( talk) 04:24, 19 February 2016 (UTC)
I removed the 'too technical' warning from the top of the page, as the page is almost unrecognisable from the July 10th version when the warning was last updated. See the following diffs that show the changes between that version and the current one [5]. If anyone thinks the article is still too technical for most readers, please specify here which sections require cleanup prior to reinstating the warning box. Thanks. InsertCleverPhraseHere InsertTalkHere 03:29, 23 January 2016 (UTC)
The result of the move request was: not moved. There is a consensus against renaming this article "Asymmetric cavity drive". However, some participants were happy with the nominator's alternate title, "Radio frequency resonant cavity thruster", and I would recommend starting a new RM to see if there is a consensus to move to that title. Sorry if that feels overly bureaucratic, but in my experience starting a new discussion for the variant is often the best way to get a clear outcome that isn't muddied by the previous proposed title. Jenks24 ( talk) 06:35, 16 November 2015 (UTC)
RF resonant cavity thruster → ? – My proposal is to rename the article Asymmetric cavity drive or Radio frequency resonant cavity thruster. Rationale for Asymmetric cavity drive can be found in section above by Tokamac. Rationale for Radio frequency rather than RF is that it makes more sense to the reader.
Brian Everlasting (
talk)
02:59, 8 November 2015 (UTC)
I see that KRAPENHOEFFER has linked this article to Pseudophysics, and proposes a major rewrite.
I agree with the assessment of this article as Pseudophysics, of the 4 reasons for considering an article as pseudophysics on that page, the second reason stated on the article in question seems appropriate. I'm disappointed that you didn't bring up the need for a distinction between PS and QS in your recent post on the Fringe noticeboard, as it was, all people said was that it was fringe, which is obvious, it was already listed as a fringe article. I don't agree that this subject is unambiguously pseudoscience, as it seems somewhere between that and questionable science.
Be careful of pushing the 'it's impossible' viewpoint too strongly, as you seem to have a very strong viewpoint on this subject. Please maintain NPOV and realise that as a fringe article, while we should make it clear that while wikipedia supports the mainstream viewpoint, there must be room to discuss and present fringe viewpoints fully. I also maintain that at least one of the fringe theories discussed in the article claims not to break conservation of momentum. This theory isn't universally accepted of course, but it does leave you with a little less room to stand on in terms of claiming that it definitely breaks the law of conservation. Please propose and discuss any major Edit Proposals on the talk page before going ahead with them. InsertCleverPhraseHere InsertTalkHere 20:14, 19 October 2015 (UTC)
1. It is worrisome for now that the main features of the EmDrive: its asymmetry and the fact the asymmetric cavity is specifically shaped as a frustum for most test articles, are not explicated in the main section of the article but appear later in the text as almost side notes. This should be addressed. The asymmetry is so important that the title of the article should perhaps be asymmetric cavity thruster.
2. As already explained elsewhere, 'cavities are resonant in principle, rendering the name "resonant cavity" tautologous'.
3. RF should also be dropped, as RF is generally said to be comprised between 1 and 3 GHz, but the EmDrive could theoretically scale to work below and above those frequencies.
4. Also already explained elsewhere: "drive" is a little better than "thruster" since we're still not sure it's pushing rather than pulling.
5. For the above reasons the name of the article should perhaps be asymmetric cavity drive — Tokamac ( talk) 20:18, 22 July 2015 (UTC)
A while back, I decided to be bold, and re-wrote the lede to use stronger language to reflect the scientific consensus that this thing doesn't work. I see that it has been changed back to the weaker language. My proposal is to reword "Their design principles seem to be not scientific, because they violate the fundamental law of momentum conservation." in the lede to the more accurate "Their design principles are rejected by mainstream science, because they violate the fundamental law of momentum conservation."
Without reliable sources indicating otherwise, failing to include the stronger language gives WP:UNDUE weight to a fringe position. If there aren't any objections, I will make the edit myself in 24 hours. -- KRAPENHOEFFER! TALK 20:56, 15 October 2015 (UTC)
This line in the lede:
A small thrust has also been observed in devices deliberately built to not produce thrust.
is disingenuous at worst, misleading to readers at best. The test in question was a control, and was used to determine if the Cannae drive creators' theory of radial slots being necessary was correct. it wants 'designed not to produce thrust' it was 'designed to test if radial slots are necessary for thrust production'. In science you might design something so that under a certain persons theory (if correct) it would not produce thrust, but you aren't making a device to specifically not produce thrust, you are doing it to test that theory. This test was a SUCCESS in testing the canna drive radial slot theory, (disproving it in favour of the competing theory that radial slots were not necessary). When this is taken into context, the line that has been inserted into the lede is very misleading, and instead suggests that there was some error in measurement, or that thrust measurements were badly made. Im reverting the edit again. InsertCleverPhraseHere InsertTalkHere 00:27, 14 October 2015 (UTC)
changed to:
A small thrust was also observed in a null test with a device lacking radial slots, indicating that the slots are not necessary for anomalous thrust production.
This both indicates that it was a null test, and makes clear what was accomplished by said null test. InsertCleverPhraseHere InsertTalkHere
I added quiet a lot to the history section which seemed to be missing a context for general public readers. Isaac Newton as reinterpreted after General Relativity was presented as a way to show that the RF resonant cavity thrusters are attempting to alter a perception that has survived several hundred years of scrutiny.
The intervening history was discussed to show that there are long standing theories and proofs about how thrust can be generated without violating conservation of momentum.
Some other writer has removed one sentence about gravity waves about which much is researched and published, but does not have a consensus and is not essential for the purpose of history.
I deleted one other sentence about interference patterns canceling Poynting vectors found objectional to one of the editors as too technical to convey a meaning.
All of the other editors are welcome to improve on the history section, hopefully to show there is a robust science of mechanics since Galileo and dynamics since Newton that Einstein didn't overturn, and many theories about thrust force have been created and tested since then without violating a long standing principle.
I'm not a fan of RF resonant cavity thrusters, but feel every topic gets a fair chance, and there are new things waiting to be discovered and published that haven't found a place yet in Wikipedia guiding principles. In that regard I have left out some of the recent history that is most contentious and is best contained in private correspondence.
As always thanks to the people who helped so far. Astrojed ( talk) 17:39, 15 September 2015 (UTC)
This page is not a forum for general discussion about EmDrive/Archive 4. Any such comments may be removed or refactored. Please limit discussion to improvement of this page. You may wish to ask factual questions about EmDrive/Archive 4 at the Reference desk. |
Using numbers representing the thrust of the EM generator shown here in Wikipedia and using the aid of superconductivity, the drive could be used on the perimeter of a wheel which drives an electrical generator which will then give vast amounts of power above what is needed to maintain the thrust. This will use one moving part plus electronics and cooling.
Development for domestic power generation will give the world a new standard of living with clean air and little need for energy from coal and petroleum.
Richard Smith — Preceding unsigned comment added by Power102 ( talk • contribs) 20:52, 4 September 2014 (UTC)
The power input for the Emdrive is electricity. It cannot be made into a perpetual motion machine because the output force could not produce enough electrical energy for self perpetuation. It's best use presently appears to be as a better propulsion system than ion drive since it does not require fuel; it can generate electricity for itself through solar cells. It also seems to be more efficient than a solar sail for acceleration. Of course all experiments so far have been small-scaled and tentative. Its biggest potential for the next century might be as a much more efficient lift-to-orbit system/ engine, and for solar system touring crafts, heavy freighters, and landing craft. This would involve large Rocket sized devices but with very small acceleration, noise, and G forces. Maybe a perfect low-cost passenger craft to the moon, mars, Jupiter's moons, and the asteroid belt, mining etc.. Much larger prototypes need to be built involving superconductive, and supercooled electrical and internal components, to show the proof-of-concept for multi-flight heavy-lift devices -- possibly at production costs as low as large aircraft. It has also been mentioned that time efficiency to get started would require rocket fuel once orbital heights have been reached. Forrestnoble ( talk) 04:51, 10 September 2014 (UTC)
...addressing the question of whether an EmDrive can drive an electrical generatoris off-topic for this talk page. It has nothing to do with the Wikipedia article. This whole thread has been purely speculative, so nothing can have been "hijacked". __ E L A Q U E A T E 18:57, 10 September 2014 (UTC)
We really should avoid presenting the working of these devices as implicit fact in the intro. Whether they work as claimed or not, their operation is still being investigated, and the jury is still out. No-one (except perhaps their inventors) would be more excited if they work than me (new physics! flying cars! etc.!) but we need to be very cautious in our reporting. The null hypothesis must still be that they don't work, until iron-clad experimental evidence is available to answer the question one way or another. -- The Anome ( talk) 10:05, 30 July 2015 (UTC)
I've now changed the intro paragraph to read like this:
RF resonant cavity thrusters are a proposed new type of electromagnetic thruster. Unlike conventional electric thrusters, they not designed to use any form of reaction mass, nor to emit any directional radiation. They have not as yet been proven to work as claimed, nor are their design principles accepted by mainstream science, which predicts that they should be unable to produce thrust. However, small thrust effects have been measured in some experiments using prototype devices, and research is in progress to see if these effects are caused by some as yet unknown phenomenon, or artifacts due to experimental error.
I hope this combines necessary skepticism with fairness to those involved. The experiments do show measurable effects, theory predicts that they must be experimental error, and experience shows that in cases like this theory is almost certainly right -- but the preliminary results are intriguing enough that it's worth keeping on researching, just in case.
And, yes, cold fusion does come to mind as a very similar situation: impossible in theory, tantalizing experimental results suggesting theory might be wrong (but with a small effect size that is hard to measure reproduceably), massively exciting consequences if real. Even though I expect the story is likely to have a similar ending to the cold fusion work a decade or so ago, I think this is currently a valid example of fringe physics, and I've added this article to Category:Fringe physics to reflect that. -- The Anome ( talk) 10:59, 31 July 2015 (UTC)
Also: I believe most of Quantum vacuum thruster should really be split off and merged into this article, as it overlaps this topic almost completely. -- The Anome ( talk) 11:19, 31 July 2015 (UTC)
The table at the top says "violates conservation of momentum" as if that was an established fact. It should say something like "Claimed by some critics to violate conservation of momentum", or "apparently violates conservation of momentum". Until we know how it works, if it does work, you can't say it violates COM.
For now all we have is the experimental data, which suggests a thrust of micronewtons, in a stationary apparatus (we don't have any kind of a spaceship drive yet).
This does appear to violate COM - but then - new physics can do that - as happened historically with beta decay before the discovery of the neutrino.
The inventors of the drive and the experimenters - neither of them say that it is a reactionless drive. And the io9 article you link to refers to an opinion of a single scientist. That is not the same as a consensus, and there seems to be a diversity of views here amongst scientists.
The theory section also should probably be filled out with more theories. For instance in the Eagleworks presentation available on video (if that is an acceptable source for the article) they gave several ideas of how it might work. Including for instance, the idea of a mild space warp (their most "out there" idea which got a lot of publicity) which would work similarly to the Alcubierre drive - and of some new kind of very weakly interacting particle to carry the momentum - and talked about ways they could test for these possibilities with experiments.
Robert Walker ( talk) 14:06, 1 August 2015 (UTC)
One suggestion, what about dividing up the theory section, and moving this block down there and using it to flag just the section on Roger Shawyer's theories? And then in that section, also give his own explanation of why he thinks it doesn't violate COM, and say why others find his explanation not convincing. And similarly label any other theories that most people think would violate COM / COE. Robert Walker ( talk) 12:57, 4 August 2015 (UTC)
I think also that this should be changed, as in accurate
" particularly because there are no compelling explanations for the apparent violation of the law of conservation of momentum,[9] and claims of such a surprising result would need especially thorough efforts to rule out possible sources of error." (end of lede)
It is sourced to a single io9 article, which in turn does voice the opinion of a scientist - but one scientist saying something doesn't make it a consensus, and it is not even a peer reviewed paper but just an interview quote. The main problem is not the apparent violation of COM, you can say that of course, but when it goes on to say "claims of such a surprising result". That suggests that the experiments if they verified the effect would also prove a failure of conservation of momentum. Which is untrue. They wouldn't prove that, any more than the experiments on beta decay proved failure of COM / COE. Just prove an apparent violation which would lead physicists to scratch their heads and try to find a new physical theory or new particles to explain it. Only a perpetual motion machine, or an infinite energy source or similar would immediately prove a failure of COM / COE with no hope of rescuing the laws with new physics. Robert Walker ( talk) 13:03, 4 August 2015 (UTC)
BTW I'm author of an article on the EM drive which may be a useful source of citations. I'm not sure how many of my citations would pass muster as citations on wikipedia, e.g. can you cite the Eagleworks video?? Or forum posts by members of the Eagleworks team and other scientists? And some of it would surely count as original research also, and it is not peer reviewed, is just a news story, but it does have a few links that may be useful. Suggestion: The EM Drive Is Getting The Appropriate Level Of Attention From The Science Community Robert Walker ( talk) 13:07, 4 August 2015 (UTC)
Anyway to explain this without violating the laws of physics. 176.252.136.138 ( talk) 17:50, 31 August 2015 (UTC)
Also it is worth mentioning that all the intermediate steps ie superconducting cavities, RF feedback at resonance are well established engineering principles. The problem is that because teams are reluctant to report null results the scientific community do not take them seriously.
I've actually run into a variant of this with my HTSC research, noticed significant resistance drops in heavy metal doped pyrolytic graphite but no journal will even look at my draft because it is not from an established research institution. — Preceding unsigned comment added by 185.3.100.53 ( talk) 10:37, 8 September 2015 (UTC)
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The only peer-reviewed article about these drives that I know of is Shawyer's recent article in Acta. Which doesn't show any positive thrust; it is a hypothetical and theoretical paper (with extraordinarily optimistic predictions). – SJ + 01:51, 8 September 2015 (UTC)
The overwhelming academic consensus is that the subject of the article is pseudoscientific. In this regards, the article clearly lends the subject undue credence, although there has certainly been a lot of hype and speculation in the media. I appreciate any help editing this to be move NPOV and I have requested the help of an expert in physics on their page. 139.222.202.221 ( talk) 11:10, 31 August 2016 (UTC)
I undid the revisions to the lede by IP above. Contrary of his claim to remove POV, their changes essentially changed the lede to be from only one POV. Furthermore, many of the changes recreated many of the older problems with the lede that were corrected via extensive talk page discussions and compromises. Insert CleverPhrase Here 21:31, 31 August 2016 (UTC)