Talk:EmDrive/Archive1

content-free
This article is amazingly content-free. The only cites to modern science support the idea, and the article offers nothing besides hand-wavey insults to debunk the idea.

I'm thinking of putting a "delete" template on it shortly. 04:27, 8 June 2009 (UTC)


 * Don't diss our resident "science-wiz". 04:31, 8 June 2009 (UTC)
 * Argh, I never want to relive those days. Except for the stealing commas from Wikipedia part, anyway.  "Human, I'm no idiot. And I know a great deal more about cat species, and indeed zoology in general, than anyone else on this site."  Crickets and tumbleweeds come to mind.  05:01, 8 June 2009 (UTC)

Rather than delete, it's worth looking into. http://www.emdrive.com/ I think is the main page for it and http://en.wikipedia.org/wiki/EmDrive can act as a decent starting point. Snark is one thing, but we do need to make the articles accurate first and then go on to the funny parts, not the other way around. 14:31, 9 June 2009 (UTC)
 * Very interesting that New "Darwin Was Wrong" Scientist picked up on it and published it. 14:33, 9 June 2009 (UTC)
 * Let's not delete. This article is an example where we can do better than wikipedia. From what I have read it seems that the EmDrive does not work. It would great to present a coherent argument for this case. Or, in the event we determine that it might work, we could argue the opposite. What I'm getting at is that Wikipedia is constrained to present well-sourced published views from experts. We are not constrained in this way. I have studied math to PhD level and mathematical physics to masters level so I'm willing to have a go at this. Does this sound reasonable or is this sort of thing outside the scope of RW? JoeDuffy 14:39, 9 June 2009 (UTC)
 * Well, the article idea appears on mission to me. If you can improve it, have at it.   14:45, 9 June 2009 (UTC)
 * I've looked at reactionless drive on wikipedia and am wondering if any RW minded people have been at it. It's very much in the style of an RW rather WP article, quoting ProjectRho and making snarkastic references to "Big Science" in only the third paragraph. Reads much better than most of WP's drier stuff. 15:04, 9 June 2009 (UTC)

Reversion
I reverted BoN's recent additions/subtractions because it seemed to be all based on a YouTube video displaying a "working" model EmDrive. The edits made the page read exactly opposite from its direction. 00:18, 12 December 2009 (UTC)
 * Is that a toaster I see to the left of Nacelle B? 01:40, 12 December 2009 (UTC)
 * I've readded the link anyway. If it's a claim that it works, we can't ignore it. Even though it looks as conclusive as... well, I'll have to think up an appropriate similie but it doesn't particularly look impressive compared to, say, the clip of VASIMR working. 14:54, 12 December 2009 (UTC)
 * Speaking of things going the wrong direction...am I the only one who's noticed that the video appears to show it rotating toward the narrow end of the cavity...the opposite of the direction of the claimed thrust? Cjameshuff (talk) 22:18, 5 July 2012 (UTC)
 * This one? No, it's hard to tell what direction it's supposed to be turning from that set up. But those most recent comments remind me why you don't discuss physics on YouTube. Scarlet A.pnggnostic 23:39, 5 July 2012 (UTC)
 * There's more pictures and video here and here which more clearly show the setup and the orientation of the cavity. There's videos at the latter link which may be somewhat better quality than the YouTube video. It definitely looks like it's rotating toward the narrow end, not the large end of the cavity.
 * Another bit...it supposedly works best when "stationary relative to their thrust", a phrase that is physically meaningless (he's not referring to inertial, non-accelerating motion, as Earth's gravitational acceleration is somehow not an issue...guess that whole equivalence principle thing was really more of a guideline). Shawyer's papers are generally muddled and confused about reference frames and seem to be assuming a universal rest frame. In his update from September of 2012, he even seems to claim it can act as a generator while decelerating. Given that a deceleration is just an acceleration in a particular direction...wouldn't just turning it around turn it into both an energy source and a reactionless drive? (For extra irony, the page is titled "Conservation of Energy"...) --Cjameshuff (talk) 02:19, 3 November 2012 (UTC)

Latest results
The Chinese are now reporting thrust of .72N (about 2.5 ounces) from their latest 2.5kW device. That's pretty meaty. See this Aviation Week article for more. -- 68.144.54.246 (talk) 06:15, 29 November 2012 (UTC)
 * On the Chinese involvement: two papers have been published, the most recent was submitted in mid 2011, Yang Juan doesn't even mention it on her faculty page, and there's been nothing else since. Looking over the version of the paper on the emdrive.com site reveals rather obvious problems...they used a stationary magnetron coupled to the cavity via a flexible waveguide. The force measured may simply have been the force between the cavity and the magnetron, transmitted mechanically or electromagnetically via the waveguide...there's nothing to indicate they tried different cavity orientations or symmetrical cavities to exclude this. Also, the thrust measured is in the opposite direction to that claimed by Shawyer, from the large end to the small end of the cavity. And contrary to the recent edit by 24.70.185.204, the claimed behavior does violate conservation of energy: a device on end in a gravity field would be an infinite energy source or sink. Cjameshuff (talk) 19:40, 2 February 2013 (UTC)
 * There's another article by the same author (David Hambling) at Wired, just as mindlessly accepting and ignorant of the reasons for criticism as the previous one. "Criticism was unsophisticated: Newton said it was impossible, therefore he must be a fraud. Even the most advanced theoretical critique, produced by John Costella, a PhD in relativistic electrodynamics, amounted to arguing about the direction of an arrow on one of Shawyer's diagrams." What difference could the direction of one little arrow make, right? And he says it doesn't violate conservation laws, and he's the inventor so he must be right, right? Cjameshuff (talk) 22:06, 8 February 2013 (UTC)
 * Both the theoretical work and the experimental evicence have been published in peer-reviewed papers, and it's been replicated independently. There has been no critique fo the Chinse theory paper. Sounds like science. biohazard
 * Sum lynx? (would be helpful is all I'm sayin') Scream!! (talk) 11:13, 20 February 2013 (UTC)

Seems that this article may be wrong
Nasa tested the drive and found it produces a net force... http://ntrs.nasa.gov/search.jsp?R=20140006052 Weird 06:49, 2 August 2014‎ (UTC)
 * In reading NASA's report it is shown that the device tested was not the same design as patented by SPR Ltd (emdrive.com) but of a different patent and design.&mdash; Unsigned, by: 184.91.165.66 / talk / contribs
 * The described tests and measurements were rather flawed (they did their tests in a vacuum chamber, and described in detail the design and operation of that vacuum chamber...and then they did their tests with the door shut, but at ambient atmospheric pressure), and they also measured an apparent thrust from a null test article that had been modified to not produce thrust. The force measured was just 30-50 micronewtons, easily measurement error due to air currents or some other factor.

https://plus.google.com/117663015413546257905/posts/WfFtJ8bYVya

https://plus.google.com/117663015413546257905/posts/C7vx2G85kr4

http://space.io9.com/a-new-thruster-pushes-against-virtual-particles-or-1615361369 Cjameshuff (talk) 23:35, 5 August 2014 (UTC)


 * The null test device was a proper emdrive just without the slots to prove the slots are not needed for operation. There was a third device that didn't produce thrust. And citing io9 is laughable - it's scifi blog.

Have to agree. There's a long way to go before Roger Shawyer's hypothesis is proven, but this page needs to be updated now that there are several positive results from reputable sources. The primary debate should be about test methodologies, but this is starting to look less like pseudoscience and more like a possibility based on NASA's latest findings. Definitely not in the same category as Time Cube anymore. 20:37, 6 August 2014‎ (UTC)

Science scepticism is about as "rational" as religion. Science needs to be open to new ideas and theories, and liberals who want knowledge to stop evolving are a funny sect. 13:05, 8 August 2014‎ (UTC)
 * The experiments were complete crap, though. In the Chinese experiment, the force per watt is ridiculously high but points the wrong way and there was an ample opportunity for classical forces. NASA's forces per watt are much much smaller, with drifts of comparable magnitude visible in the graphs as measured, because it was done in the air. It's obvious what needs to be done: dual suspension that measures force and torque independently (and which will not react to minor bending of cables under load), equipment and electronics in a sealed container with a battery, made of permalloy to shield magnetics and electrostatics, the whole thing under high vacuum. But they don't want the equipment to be shielded in a box, they want a vacuum rated RF amplifier, which is expensive, and will outgass producing reaction forces and screwing up the measurements to the point where they'll produce more publicity yet. Dmytry (talk)


 * Can someone look at this? It details some test methodology that the NASA abstract didn't mention (which addresses some issues brought up by the previous comment). I can't seem to find the full report from NASA's experiments though.
 * http://www.wired.co.uk/news/archive/2014-08/07/10-qs-about-nasa-impossible-drive
 * I may not be a scientist, but NASA definitely isn't new at testing propulsion systems. I don't know how many of you here are actually experts in the relevant firlds, but may be we should be careful about dismissing all these experiments as "crap". &mdash; Unsigned, by: Lorien / talk / contribs
 * NASA is new at testing such tiny forces; they just built the apparatus. Dmytry (talk) 13:45, 26 April 2015 (UTC)
 * Yeah, I'm from the land of the big forces (or at least the land of the museum of the big forces), which are kind of NASA's thing. PacWalker 13:49, 26 April 2015 (UTC)
 * Even the ion thrusters usually produce forces at least 1000 times larger. Dmytry (talk) 03:30, 29 April 2015 (UTC)


 * Some comments on the validity of experimental results: These folks are pumping substantial microwave power into a closed metal box at resonance. There is heat, of course, which has to go somewhere; this will expand and twist structures. But, at resonance there will be extremely high voltages and magnetic fields. Pumping a kilowatt into a closed cavity, as the Chinese and German groups did, is going to cause some highly dramatic effects--Corona discharges, sparks. Magnetic fields that can interact with the enclosures. Blown Cavity Magnetrons. Showing that measured 'thrust' is not due to one of these phenomena is nearly impossible.


 * The Eagle Work results were actually much more negative than they presented them. They tested 3 cavities of completely different designs (and supposed theories of operation) and got essentially the same results. In particular the "Cannae Drive" lacking the special slots claimed necessary by its inventor gave the same thrust as the supposedly working model. That device appears symmetrical; there is not even a technobabble explanation for the thrust. The obvious conclusion is that the thrust is due to some conventional effect.


 * The work was extremely preliminary and crude (8 days of work). Making these conclusions public was deeply irresponsible.


 * Until there is work published in legitimate refereed journals, the EmDrive should remain classified as a Perpetual Motion Machine.MervinFerd (talk) 05:08, 22 August 2015 (UTC)

Let's talk about conservation of energy and relativity
Why isn't anyone mentioning that EmDrive necessarily violates either conservation of energy or the lack of an absolute reference frame, regardless of whether or not it violates conservation of momentum?


 * $$E_k = \frac{m_0 c^2}{\sqrt{1-\frac{v^2}{c^2}}} - m_0 c^2$$

Let's suppose that we have a spaceship with a mass of 1 million kilograms, and it accelerates at 1G, or 9.8 m/s2, and it is powered by an EmDrive with a thrust of 10N/kW. Therefore, it will require 981 MW, or 980.7 MJ per second. (Lower efficiencies will delay the spaceship's transformation into a free energy machine, but it will happen sooner or later unless it is equal to or less efficient than a photon rocket, which is a hideously inefficient method of propulsion.)

After one second, the ship will be traveling at 9.8 m/s. Its kinetic energy from a reference frame in which it is traveling at 9.8 m/s is 48 MJ. It will have spent 980.7 MJ.

After two seconds, it will be traveling at 19.6 m/s. Its kinetic energy from the same reference frame as the first is 192.1 MJ. It will have spent 1,961 MJ. The kinetic energy has quadrupled, despite the velocity only doubling, and the expended energy only doubling.

After ten seconds, it will be traveling at 98 m/s. Its kinetic energy from the same reference frame is 4,808 MJ. It will have spent 9,807 MJ. The kinetic energy is 100x what it was the first second, but it has only spent 10x that amount of energy.

After 100 seconds, it will be traveling at 980 m/s. Its kinetic energy from the same reference frame is 480,886 MJ. It will have spent only 98,066 MJ. Oops.

This tends to be hand-waved away, saying that the device becomes less efficient at higher speeds. But that requires a reference frame (which a reactionless propulsion device doesn't have); otherwise, there is no difference between a stationary object and a moving one. But perhaps Einstein was wrong. But that's still an extraordinary claim, and we all know what that means. EmDrive and friends deserve every bit of skepticism it was met with 10 years ago, and it will continue to deserve every bit of skepticism until they get a lot more thrust than 116 µN. Show me a completely sealed EmDrive floating in a vacuum, and then we'll talk. — 22:40, 8 April 2015 (UTC)
 * Good point as well, albeit the types that want to believe will just say, there's a preferred reference frame, so what. Also, it would've been okay with 116 micronewtons, if they didn't have drifts that size. See this shit: http://i.imgur.com/VbriL4J.jpg . Now what we should be studying, is this *increasing* thrust the other way, requiring no energy input, after they had charged the hyperdrive. lol. Dmytry (talk) 13:57, 26 April 2015 (UTC)
 * I pointed out some conservation problems earlier on, actually, and it's even simpler than you show. Among the things Shawyer claims is that the EmDrive is a reversible electric machine: that it'll produce power output from acceleration. Gravitation on Earth's surface provides 9.8 m/s^2 for an unlimited amount of time for no power input.
 * Amusingly, not only does Shawyer assume a universal rest frame, with gravitational acceleration being somehow special in violation of the equivalence principle, his various vehicle concepts using the EmDrive to hover and other propulsion systems to accelerate make it clear that the special rest frame he has in mind is that of Earth's surface. Shawyer's evidently a geocentrist. Cjameshuff (talk) 16:17, 30 April 2015 (UTC)

-- There is a simpler demonstration of Conservation of Energy violation. If the Gizmo is attached to an arm on a rotating axle, power output will exceed input when (Thrust X Velocity) exceeds the input power. A dynamo on the axle could harvest the power, keep the thruster going and send excess to the power grid: It's a Perpetual Motion Machine of the First Kind.

MervinFerd (talk) 04:35, 22 August 2015 (UTC)
 * Yeah, but they can handwave about loss of efficiency due to motion and keep things confused with that example. That's why my example uses an EmDrive that is stationary w.r.t. Earth's surface, using gravitational acceleration to either create or destroy energy. It makes it harder to hide that Shawyer's blather about static thrust and dynamic systems is in direct opposition to basic physical principles.--Cjameshuff (talk) 13:25, 23 August 2015 (UTC)
 * Though if you want a "dynamic" example, construct a typical float belt setup (http://rationalwiki.org/wiki/File:Prepex2.svg) with a belt of EmDrives, turned on for the climb and turned off for the descent. The EmDrives don't "accelerate" in Shawyer's terms and so they don't consume power, they are turned on while moving upward, continue to rise at constant velocity (assuming mechanical power is constantly removed from the system at the rate they add it), and are then turned off. --Cjameshuff (talk) 13:37, 23 August 2015 (UTC)
 * Ahh, Hell, none of this makes any sense. Some nice perpetual motion machine using the EmDrive, nicely drawn out, would be a useful teaching tool. A lot of people who do not understand how fundamental Cons of Momentum is, but understand that there is no free lunch.


 * I hadn't seen that particular PPM before. Took me a minute to figure out the problem. MervinFerd (talk) 17:07, 24 August 2015 (UTC)

Let's talk about conservation of no net linear momentum
"The propellant expelled by a reaction drive need not be a material substance: photons carry momentum proportional to their energy, and so a drive that simply directionally emits photons will produce thrust (albeit very small amounts of thrust for a given power input)."

Sorry, the above is wrong: https://www.quora.com/Can-you-help-me-expose-the-radiation-pressure-theory-behind-solar-sails-as-a-sham. Lysdexia (talk) 19:31, 17 November 2015 (UTC)
 * I am not sure I am reading it as intended. I think the EM drive is shit, but wp:radiation pressure is completely real.  EM radiation pressure corresponds with the nature of light, and it can be seen easily in comets, which caused its discovery by Kepler.  -EmeraldCityWanderer (talk) 19:46, 17 November 2015 (UTC)
 * You neglected to account for the fact that the IKAROS sail is not perfectly flat (it's actually rather wrinkled) and you assumed it would be pointed face on toward the sun. The measured thrust is right where it should be for radiation pressure, and several orders of magnitude higher than anything the solar wind could provide. The objections listed on that page are gibberish (as far as they make sense at all, you seem to be arguing that light doesn't exist), and the solar wind simply doesn't carry the momentum required to produce the thrust, no matter how much you wave your hands about unspecified photoconductivity effects. The existence of radiation pressure is just not something that is in doubt. It is easily tested, and in some fields has to be taken into account in real-world engineering. If your analysis shows it doesn't exist, what you have found is an error in your analysis.--Cjameshuff (talk) 00:51, 18 November 2015 (UTC)

2015 tart-up
This is stupidly big news for no good reason, so I've just given this a restructure. Needs moar. User:Dmytry has been arguing with idiots on this topic, and will hopefully contribute - David Gerard (talk) 20:58, 3 May 2015 (UTC)
 * What is the policy on using images from a pseudoscience forum or website? I chased down the (only two) in-vacuum graphs they ever released, http://imgur.com/a/oosju, I can explain the legend on them in the article. Pictures like this speak louder than words especially if contrasted to a representation of what you would expect from an experimental apparatus that is working right (plots where the thrust looks as neat as the first calibration pulse, where they apply a known force to the pendulum), and a zoom-zoom-zoom-Cavendish Experiment . The only truly mind blowing thing is that 217 years ago, Henry Cavendish had measured a force smaller than a single pixel on NASA's charts, and his error comparing to the modern value was 1.1% Dmytry (talk) 15:58, 4 May 2015 (UTC)
 * I bet you as long as it isnt promoting psuedoscience, you can post it if you can find a place for itBubba41102 Taste the shortness` 16:01, 4 May 2015 (UTC)


 * I think you could probably reasonably claim fair use, since the images in question (the ones you showed me?) would be the ones supporters are putting forward. Put in full source and a reason we're using them and we should be fine. If they're originally from NASA, of course, they're US Federal Government public domain - David Gerard (talk) 21:19, 4 May 2015 (UTC)
 * I hunted down the original post with one of the graph but not the other yet. The understatement of the year: "The reverse thrust signals for the 1937.15MHz thrust signals are not the negative going mirror images of the forward or positive going thrust signatures as one would have liked" . Also everyone involved has prior involvement with "Woodward Effect" drive; the portrayal of this as an independent confirmation by initially skeptical NASA seems rather misleading to me; if NASA hired Pons to test cold fusion, that's very different from assigning a skeptical electro-chemist to the task. Dmytry (talk) 21:29, 15 May 2015 (UTC)

Welp
According to NASA itself, EmDrive seems to work so far, as long as it's in a vacuum. It doesn't appear to be an experimental error from the test they made in April. Thoughts? Serocco 01:51, 4 June 2015 (UTC)
 * That's a rehash of the stuff already known. Also, Shawyer as a scientist? - David Gerard (talk) 12:07, 4 June 2015 (UTC)
 * Oh, I didn't know this was already discussed before. Well, what is the consensus over EmDrive? More experiments before proven to be full-on pseudo science or plausible? Serocco 12:38, 4 June 2015 (UTC)
 * If only there were a RationalWiki article on the topic ... - David Gerard (talk) 17:28, 4 June 2015 (UTC)

The article should add a rebuttal to this claim
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20140013174.pdf

This paper claims on page 11 that a regular ion thruster suffers from the same conservation of energy problem as the EmDrive. I believe the author forgot to take the kinetic energy of the propellant into account. If I can wrap my head around the math, I'll try to verify my suspicion personally, but don't count on it. I suck at math. — 22:46, 22 June 2015 (UTC)


 * You are correct, one has to account for the kinetic energy of the propellant. The analysis of ion thrusters is no different from the analysis of any other rocket, and their acceleration actually improves as they consume propellant and become lighter.
 * In the given example, the exhaust velocity is about 18 km/s. He claims an excess of 33649 GJ (significant figures? What are those?). The kinetic energy of the propellant after the burn (assuming an instantaneous burn for simplicity) is: 0.5*540 kg*(371 km/s - 18 km/s)^2 = 33644 GJ. The difference is down to simplifications and rounding, goes away with a little calculus, and certainly isn't two orders of magnitude larger than the output of the thruster.
 * Now, in a reactionless drive, you have no propellant to balance the energy budget with...just handwaving about pushing against the universe and assurances that the math will work out by a guy who just shrugs and calls it a paradox when he finds he's failed to account for a huge chunk of energy. Cjameshuff (talk) 03:33, 23 June 2015 (UTC)
 * Pls add this to article. Cømrade FυzzчCαтPøтαтø (talk/stalk) 13:10, 23 June 2015 (UTC)


 * Okay, I've tried doing the math, and now I'm confused. The author of the paper implied that there was excess energy ("The change in kinetic energy is 33,649 Gigajoules, which is  two orders of magnitude larger than the energy provided by the power system"), yet when I do the math, it seems that the total kinetic energy of the ship decreases as it accelerates (688 TJ at 371 km/s, and 654 TJ at 372 km/s), rather than increasing as implied.  — 22:11, 23 June 2015 (UTC)
 * Yeah, I meant to point that out, but lost it in editing...he's looking at the change in kinetic energy of the spacecraft + propellant and ignoring both the change in mass (and thus the change in kinetic energy of the propellant) and the sign of that change. The spacecraft itself does increase in kinetic energy, but his figure for initial kinetic energy is for that of both spacecraft and propellant together. If you're confused, it's probably because you're looking at an analysis written by someone who is deeply confused. Cjameshuff (talk) 23:15, 23 June 2015 (UTC)
 * Here's a more complete calculation: http://codepad.org/QKTsjIGe
 * ke_start is the initial kinetic energy of spacecraft + propellant, ke_end is the final kinetic energy of the spacecraft, ke_prop_end is the approximate final kinetic energy of the propellant. The overall change in energy is accounted for by the energy put into the system by the engine accelerating the propellant by 18 km/s. Cjameshuff (talk) 00:19, 24 June 2015 (UTC)

Now would that be awesome...
...if that thing'll work. It could be the thing to revive manned spaceflight, but probably it won't and humankind will stay confined to Earth for another long, long time.--Arisboch ☞✍☜☞✉☜ 17:11, 24 August 2015 (UTC)
 * Until a gamma ray burst wipes us off the face of the Earth... 142.124.55.236 (talk) 17:16, 24 August 42015 AQD (UTC)
 * I know, right? It's really a shame.--Arisboch ☞✍☜☞✉☜ 17:21, 24 August 2015 (UTC)
 * Well, I guess if escaping from Earth isn't on the table, I guess all we can do is go undergound. Cue a The Time Machine-future. 142.124.55.236 (talk) 17:24, 24 August 42015 AQD (UTC)
 * Or something like in Space Battleship Yamato, just without these Gamilas fuckers irradiating the surface and hopefully with a chance for survival.--Arisboch ☞✍☜☞✉☜ 17:27, 24 August 2015 (UTC)
 * Or you know, nuclear. Nuclear might work.  ikanreed You probably didn't deserve that 17:31, 24 August 2015 (UTC)
 * Yeah, that can happen, too, cause who knows, when a similar guy to Stanislav Petrov won't be around, right?--Arisboch ☞✍☜☞✉☜ 17:33, 24 August 2015 (UTC)

/r/EmDrive is unhappy
They don't seem to have any serious counterarguments, though. 16:02, 12 September 2015 (UTC)
 * Yes, the bulk of the "criticism" (or rather, disappointment) seem to come from people who whine about the tone of the article, and thus people who are unfamiliar with the mission statement and seem to hope for a Citizendium-type representation of their lovely and totally not pseudoscientific hopes and dreams. Though let me be the first to say that the article can always be improved - just last night stuff was added to it to make it that little better. Oh, and the best part was when people tried to complain via arguing that this article of ours wasn't "very encyclopedic". Reverend Black Percy (talk) 16:52, 12 September 2015 (UTC)

Possible explanation
I found this interesting post on reddit

TL;DR version: it is possible (perhaps even likely) that the EmDrive "works" by ejecting material from the walls of the device. If so, Shawyer accidentally made an inefficient ion thruster. — 04:55, 2 November 2015 (UTC)


 * If anything, he might be looking too hard. The Eagleworks experiments were melting nylon bolts inside the cavity...think they've got a solid grasp of how to control and account for outgassing? They have a wide variety of basic flaws in their experimental setup, any one of which could explain the results.--Cjameshuff (talk) 20:43, 7 November 2015 (UTC)

gravitational force of a penny
My edit changing "gravitational force of a penny" to "weight of a dime" was reverted? Not only does the formula for gravitational force require two masses so that the phrase "gravitational force of a penny" is as meaningless as saying "the magnetic force of an MRI magnet", the writer clearly meant weight of a penny (0.025N) as it is close to the 0.016N. Even then, the force of a dime's weight (0.023N) is at least a bit closer.

Not a terribly rational reversion.

174.56.100.127 (talk) 03:50, 28 December 2015 (UTC)
 * But then "weight of a penny" would also be meaningless, as a penny weighs less on the moon. Also,   "weight" literally IS "gravitational force".  Why do you seem to be making a distinction?  Brianpansky (talk) 05:19, 11 January 2016 (UTC)

distinguishing experimental results from theories
It will be easier to achieve clarify if experimental results from NASA, China, and Germany are considered separately from the theories proposed by the inventors. NASA's Eagleworks experiments, for example, showed the same apparent thrust with or without "slots" which the inventor thought necessary. Similar apparent thrusts were observed for both tested designs, despite quite different inventor theories - clearly they are not both right and more likely they are both wrong. If (just if) the experimental results were to eventually be well validated, I suspect that the inventors' theories would be summarily discarded and new physics would needed (the inventors having only been lucky to stumble upon a new effect they did not understand). Much more likely it will turn out to be experimental error - but we don't know when or how some real anomaly will show up that contradicts parts of our current understandings of physics. Anyway, the point is - discrediting the inventors' theories is barely worth the effort as it's only a sideshow; but it has nothing to do with discrediting experimental results - which is the main thing making these alleged drives newsworthy. So let's keep them separate. Sniping about how some experimental result is inconsistent with the inventors' theories is only a distraction from any real questions. Pointing out that being fully bidirectional implies free energy from gravity only discredits a theory which had no weight to begin with, not the experimental results.

There should be two sections: experimental results so far and their trustworthness, and proposed theories. Shoot at them separately.

And no, experimental success would not destroy science, any more than relativity or quantum theory did. Or for that matter, the anomalies which have been somewhat vaguely attributed to dark matter and dark energy, which are more placeholders for some eventual fuller explanation. Anomalous thrust (in the unlikely case that it eventually panned out) would require some form of refinement built upon but extending the well validated science that we have. It would be more accurate to say:

The key thing about it is that if it works, it would constitute an unexplained exception to several extremely well-tested principles of physics.

Because the areas where the conservation laws have been well validated would remain validated, not be thrown out the window. Newtonian physics was not discarded, nor was non-quantum physics. The focus would be on understanding the nature and limits of the implied exceptions to "normal world physics as we've understood it to date". (Again, my money would be experimental error as much more likely; just trying to be a rational skeptic about it all rather than cling irrationally to "current theories" as known complete descriptions of the universe, even if we know they must be pretty close to accurate under a wide range of conditions) -

Totally agree with above. The whole tone of the piece about how this would destroy the laws of science is completely wrong. Many great experimental results such as Rutherford and Michelson Morley went against accepted science. This is what made them great!

The part about how a preferred frame would contradict all of relativity is particularly cringe worthy. Since this is the exact argument Einstein used to argue against the quantum teleportation experiment working. And it has since actually worked.&mdash; Unsigned, by: 161.200.188.115 / talk / contribs 14:23, 8 March 2016
 * The thing is, it contradicts with experiments that had measured the electromagnetic waves directly, without ever observing any apparent deviation from conservation of momentum or energy down to an extremely high degree of precision when the electromagnetic waves were measured electrically rather than mechanically. The force conveyed by electromagnetic waves is equal to power divided by the speed of light; i.e. for every microNewton of thrust impacted on the cavity by electromagnetic waves (after said waves interacted with the "quantum vaccuum" or what ever), you'll need at least 150 watts worth of electromagnetic radiation "anomaly". If there was an effect of this magnitude that we didn't know about, we would be unable to have this conversation as a large fraction of communication equipment would mysteriously not work; we maybe wouldn't have noticed the extra forces before these guys came around but we sure as hell would have noticed the electromagnetic fields involved back around 1900 or so. Dmytry (talk) 15:41, 26 August 2016 (UTC)