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from the that-still-doesn't-mean-it-will-work dept.
After months of speculation and leaked documents, NASA's long-awaited EM Drive paper has finally been peer-reviewed and published [open, DOI: 10.2514/1.B36120] [DX]. And it shows that the 'impossible' propulsion system really does appear to work. The NASA Eagleworks Laboratory team even put forward a hypothesis for how the EM Drive could produce thrust – something that seems impossible according to our current understanding of the laws of physics.
In case you've missed the hype, the EM Drive, or Electromagnetic Drive, is a propulsion system first proposed by British inventor Roger Shawyer back in 1999. Instead of using heavy, inefficient rocket fuel, it bounces microwaves back and forth inside a cone-shaped metal cavity to generate thrust. According to Shawyer's calculations, the EM Drive could be so efficient that it could power us to Mars in just 70 days.
takyon: Some have previously dismissed EmDrive as a photon rocket. This is addressed in the paper along with other possible sources of error:
The eighth [error:] photon rocket force, RF leakage from test article generating a net force due to photon emission. The performance of a photon rocket is several orders of magnitude lower than the observed thrust. Further, as noted in the above discussion on RF interaction, all leaking fields are managed closely to result in a high quality RF resonance system. This is not a viable source of the observed thrust.
[...] The 1.2 mN/kW performance parameter is over two orders of magnitude higher than other forms of "zero-propellant" propulsion, such as light sails, laser propulsion, and photon rockets having thrust-to-power levels in the 3.33–6.67 μN/kW (or 0.0033–0.0067 mN/kW) range.
Previously: NASA Validates "Impossible" Space Drive's Thrust
"Reactionless" Thruster Tested Again, This Time in a Vacuum
Explanation may be on the way for the "Impossible" EmDrive
Finnish Physicist Says EmDrive Device Does Have an Exhaust
EmDrive Peer-Reviewed Paper Coming in December; Theseus Planning a Cannae Thruster Cubesat
(Score: 4, Funny) by EvilSS on Tuesday November 22 2016, @03:28PM
(Score: 1, Funny) by Anonymous Coward on Tuesday November 22 2016, @04:11PM
Now excuse me, I need to go grab some popcorn.
Do you know what kind of science it takes to pop that popcorn? Of course you don't because science can't explain it! Popcorn Creationism for the win!
(Score: 0) by Anonymous Coward on Tuesday November 22 2016, @04:16PM
fuckin magnets how do they work
(Score: -1, Troll) by Anonymous Coward on Tuesday November 22 2016, @04:46PM
Take apart a vibrator to find out.
(Score: 2) by fritsd on Tuesday November 22 2016, @07:04PM
fuckin microwaves [wikipedia.org] how do they work, and what's the connection between popcorn and VASIMR?!?11?
(Score: -1, Troll) by Anonymous Coward on Tuesday November 22 2016, @07:17PM
Oily lube.
(Score: 0) by Anonymous Coward on Tuesday November 22 2016, @07:22PM
Simple: Intelligent Attraction.
(Score: 2, Funny) by khallow on Tuesday November 22 2016, @06:31PM
(Score: 2) by DannyB on Tuesday November 22 2016, @04:43PM
Will this drive improve our understanding of physics? Or is the principle of its operation already well understood?
In an earlier millennium there was this thing called "The Edison Effect". Where somehow current could flow from the filament of a light bulb to a plate within the same glass bulb. This explained and confirmed some things. But it must have seemed quite spooky at the time.
The lower I set my standards the more accomplishments I have.
(Score: 2) by mcgrew on Tuesday November 22 2016, @05:56PM
But it must have seemed quite spooky at the time.
In 1926, Hugo Gernsback called electricity the mysterious fluid. [mcgrewbooks.com]
mcgrewbooks.com mcgrew.info nooze.org
(Score: 3, Interesting) by ledow on Tuesday November 22 2016, @08:09PM
Well, according to what I read, we know that the wave-particle dualities are there. Every schoolboy has done the double-slit experiment to prove that light acts like a wave, even if it acts like a particle elsewhere.
And we know that we don't yet have a conclusive interpretation of the quantum world, just a few good guesses.
But even back in the 20's when this stuff was in its infancy, fluid-modelled stuff was showing promise but then sidelined by other interpretations.
The paper's authors appear - but I can't say they are doing so impartially - to imply that such a thing could explain the extra force generated by... well... nothing. It's literally using waves in a vacuum (all vacuums have waves and energies and all kinds of stuff in them, just not classical particles) to get a small "bounce" off it - it's literally bouncing off empty space and gaining energy from a wave field that permeates all space, even vacuums. It's a little like surfing - the wave is there, going up and down, and normally you just bob up and down with it, but if you get the right conditions, you can use it as a form of propulsion. That's what they say is happening here... they are riding a wave that other quantum interpretations don't have or don't rely on to explain things.
And the background material linked has a classical-physics demo that appears convincing to my mathematician-but-hate-physics eye. Bounce a tray of fluid enough at the right rate and you can drop a drop of the same fluid into it and the drop will bounce forever, hitting the fluid and bouncing back up, staying separate the whole time, generating ripples in doing so, which become waves which help it bounce again the next time in a form of resonance. Do it right, and the drop will not only bounce forever, though, but - on a otherwise flat but vibrated surface - it will actually surf a little tiny wave in the underlying fluid with each bounce. There's some videos linked via the fluids discussion in the conclusion of the paper. The drop is going bounce-bounce-bounce up and down but a wavefront forms and gives it a tiny nudge in a direction.
If you track that "wandering" enough, you'll see that it confirms to a lot of the probabilities that quantum physics tries hard to explain. You can't guarantee where the particle will be but if you measure it long enough it conforms to quantum expectations, including peaks and troughs where you'd expect if the probability were higher/lower. Bouncing "walkers" interact like quantum particles. Steer them through double-slits and you see the same kind of phenomenon that we see with double-slit experiments. The waves break up, interfere, reinforce and cancel out, like a wave does, and that affects where the particle (the bouncing drop) could end up too. Get enough particles and probabilistically you see them act like waves, overall. It would seem - to an amateur - to marry quantum and classical worlds quite nicely. It's certainly an interpretation of quantum physics that I "prefer" as a mathematician, but I have no idea of the maths behind it.
It seems to be a theory undergoing some recent resurgence, but whether that's just bandwagons and opinion or fact isn't proven or disproven by this paper. It merely suggests it as a possible explanation, that isn't explained by other interpretations. It could be bunkum. But the underlying theory sounds plausible, the effect is measurable and unexplained, and nothing else comes close to telling you what could be happening. Everyone else basically says you shouldn't be able to get energy from a vacuum like they are provably doing.
All this proves, though, is that there's an effect in there that we can't really explain completely. Experimenting in a reproducible test is the best way to learn and discover, and it appears that we have a reproducible test to work with. That means, whatever happens, we're about to learn something about the universe. How important that is, whether it will completely blow out Copenhagen interpretations, etc. is unknown.
But - like me reading the paper and background citations - we will definitely learn something that we don't currently know.
(Score: 1) by Demena on Tuesday November 22 2016, @11:21PM
Ack! You 'believe' in Hawking radiation, right? Produced by one of a pair of particles from a black hole escaping? What happens to the other particle left behind the event horizon? Cue: Unruh radiation. Unruly was not what you would call an armchair physicist
(Score: 2) by ledow on Wednesday November 23 2016, @07:58AM
The Hawking radiation that nobody has ever observed, despite several missions designed to find it? Given that it was first proposed in 1970-something, that's quite a time to remain without any experimental evidence whatsoever.
To be honest, I'm not saying I don't. I'm saying that having an easy, imaginable method of how particles and quantum-level entities operate is much more useful and simpler tool, and simpler is often better.
And I'm not sure that either are somehow excluded by such effects anyway.
(Score: 1) by Demena on Wednesday November 23 2016, @08:39AM
That Hawking radiation has not been observed is a legitimate statement but it also applies to an electron. For both there is lots of evidence but neither is directly observable. Sure Hawking radiation is buried a little deeper but if it is not there we lose too many good explanations for too many things. But it is the other side of the coin, Unruh radiation, that I am intrigued by. If we find meta materials that can affect if or be affected by it then magic may happen. And there is an experiment or two that may be almost direct observations.
One of the beauties of MiHsC is that it is so simple and so much falls out of it. MiHsC predicts effects that that are observable and measurable. Many of them. It provides a simple model for inertia that explains the dynamics we observe throughout the universe on multiple scales more accurately than any dark matter/dark energy hypothesis. It also provides an explanation of the EM drive and provides formulae to calculate the thrust produced by different designs. It explains a lot of current anomalies really well.
http://physicsfromtheedge.blogspot.com.au/2014/01/mihsc-101.html [blogspot.com.au]
(Score: 1) by Demena on Tuesday November 22 2016, @11:13PM
Well it is not understood by it's discoverer (not inventor) but it is well explaned (predicted even) in MiHsC.
(Score: 0) by Anonymous Coward on Tuesday November 22 2016, @04:48PM
I didn't know that the physics of armchairs is such a popular topic. :-)
(Score: 2) by bob_super on Tuesday November 22 2016, @06:03PM
If you're gonna spend a quarter or a third of your life sitting on something, you should get familiar with it.
An elder gentleman, when I was in college, pointed out that we spend more time holding a mouse, running our fingers on a keyboard, and staring at a screen than we do the same actions with our sex partners. And the lifespan of our relationships is often much longer with the former. Yet we usually don't dedicate anywhere near as much time or money picking them...
(Score: 0) by Anonymous Coward on Tuesday November 22 2016, @07:57PM
yeah. do you realize most people actually don't spend any time at all choosing their own children?
this is a person who will live with you for 20 years, you will have to provide for all their wants and needs, and deal with all of their problems, but you spend zero amount of time choosing between the different options. unless you adopt.
(Score: 2) by bob_super on Tuesday November 22 2016, @08:02PM
I'm also gonna spend a lot less time deciding the color of the asteroid that will obliterate civilization than I did choosing today's socks.
Thanks for false equivalences, but I don't live in a place where my spouse was chosen for me.
(Score: 0) by Anonymous Coward on Wednesday November 23 2016, @01:33AM
"Yet we usually don't dedicate anywhere near as much time or money picking them..."
Men used to just marry a cute female child.
They didn't used to have to spend too much time picking which roastie whore would stab them in the back.
(Score: 1, Interesting) by Anonymous Coward on Tuesday November 22 2016, @03:33PM
Use red + blue or green + blue next time. Are NASA really the journal of propulsion and power really ignorant of this issue? I thought altered colored perception was supposed to be correlated with proclivity to engineering/math.
(Score: 0) by Anonymous Coward on Tuesday November 22 2016, @03:49PM
Only as long as it's pure red vs pure blue. My flavor of colorblindness can distinguish red, but it's vastly diminished. I struggle with some purples. Same deal with brown. Strangely, orange is generally safe though.
(Score: 2, Informative) by Anonymous Coward on Tuesday November 22 2016, @04:25PM
Any line graph should be done in a way that you still can distinguish them on black/white prints. Usually for more than one curve, this means using dashed or dotted lines in addition to different colours. Quite obviously, this also helps with all sorts of altered colour perception.
(Score: 2) by DeathMonkey on Tuesday November 22 2016, @06:58PM
The above post is my nomination for the EvilSS Golden Armchair award!
(Score: 2) by takyon on Tuesday November 22 2016, @07:04PM
I pick https://soylentnews.org/comments.pl?sid=16638&cid=431343#commentwrap [soylentnews.org]
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
(Score: 2) by takyon on Tuesday November 22 2016, @03:33PM
There are a couple of grammar errors in the paper, but it is described as an "Article in Advance", and it's not December yet. This paper was leaked a while back, but this release should be official enough to address your basic concerns.
This thread [nasaspaceflight.com] actually contains Paul March answering questions (his nick is Star-Drive [nasaspaceflight.com]), and may be an interesting read if you have the time to deep dive into it. You might want to skip to page 150 or so and just read the last couple of days.
As excited as I am about the implications of a working emdrive, I have to admit that I glaze over when I try to think how an emdrive-equipped spaceship with solar panels could beat a solar sail by orders of magnitude. Emdrive could still be a giant fraud/mistake. If it does work, it will cut down on various solar system travel times at the least, although solar panels won't be ideal for some journeys.
Keep in mind that Roger Shawyer is teasing upgraded systems that supposedly put out an obscene amount of N/kW, even enabling terrestrial flight (Back to the Future II style). This might affect your view of the feasibility/scamminess of all this.
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(Score: 2) by GreatAuntAnesthesia on Tuesday November 22 2016, @04:09PM
> even enabling terrestrial flight (Back to the Future II style).
In that case the next NASA paper on the subject will be an investigation into the environmental / health effects of this thing. It's all very well up in space where there is very little to pollute, but I know I wouldn't want BTTF-style flying cars & hoverboards buzzing about over my head until I knew they weren't going to give me cancer or catastrophically poison the environment somehow. And if we don't know exactly how it works, the only way we can assess the potential impact on our surroundings is by lots and lots of long-term animal (and maybe later human) experiments, which could be a decades long process.
But yeah, the space applications are very exciting. Asteroid mining, off-world colonies, it all suddenly looks a lot more achievable.
(Score: 0) by Anonymous Coward on Tuesday November 22 2016, @04:15PM
It is new so there is always some concern, but it is more like a weirdly shaped microwave oven. As long as it doesn't leak too much there shouldn't be a problem.
(Score: 2, Insightful) by Anonymous Coward on Tuesday November 22 2016, @04:52PM
The point is, it has effects that we cannot explain and didn't expect. So it also might have other effects we cannot explain and didn't expect.
It's just like with the discovery of X rays. People didn't think of them as dangerous until people started getting cancer from it.
(Score: 2) by turgid on Tuesday November 22 2016, @10:54PM
In Soviet Russia. microwave ovens were banned, or at least so said a young earth creationist with an interest in nutrition. Make of that what you will :-)
I refuse to engage in a battle of wits with an unarmed opponent [wikipedia.org].
(Score: 2) by takyon on Tuesday November 22 2016, @04:22PM
And why would you want a NASA paper on it? Roger Shawyer is the one with the secret magic flying car sauce known as EmDrive 2.0, not NASA. And he has supposedly partnered with a previously unnamed UK aerospace company [ibtimes.co.uk], which is now said to be Gilo Industries Group [ibtimes.co.uk], the makers of Parajet Skycar [wikipedia.org]. Not NASA. He also claims that the US Department of Defense and UK Ministry of Defence are interested in it, not NASA.
I guess it would be bad if the thrust was some kind of crazy radiation that was extremely harmful to life, but if it is, it will probably be found out before it ever hits market or demo stage. Just gotta get some poor sap from engineering to stick their hand in front of the RF resonant cavity (actually, the new version might not have anything that looks like a cavity/nozzle).
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(Score: 3, Insightful) by bob_super on Tuesday November 22 2016, @06:20PM
> the thrust was some kind of crazy radiation that was extremely harmful to life, but if it is, it will probably be found out before it ever hits market or demo stage
By the defunded EPA, the defunded OSHA, the defunded DOE, or the defunded NASA?
Oh! I know, I know! Thanks to the negative studies and lawsuits generously financed by the established corporations fighting a new entrant in the propulsion market!
Thanks for protecting us, FreeMarketMan!
(Score: 2) by takyon on Tuesday November 22 2016, @06:55PM
It's energy thrust, not asbestos/dioxin/benzene spray. The only thing complicated about it is making more of it.
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(Score: 1) by Demena on Tuesday November 22 2016, @11:34PM
It works by changing the inertial weight of in-flight photons. Thus the drive needs to move -thrust- for conservation of momentum. Basicly it is a giant Casimir effect. It should not be a problem. Nor do we have to imagine dark matter or dark energy anymore. This, MiHsC, explains all four effects.
(Score: 0) by Anonymous Coward on Wednesday November 23 2016, @01:37AM
This, MiHsC is hitler though?
(Score: 2) by takyon on Wednesday November 23 2016, @04:34AM
Back away from the Amazon Prime TV!
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
(Score: 0) by Anonymous Coward on Wednesday November 23 2016, @06:14AM
But MiHsC is hitler, right?
"I will raise from the grave and then you will know that I was right"
Direct conversion of energy to momentum is what he was speaking of, correct?
(Score: 2) by mcgrew on Tuesday November 22 2016, @06:04PM
You guys don't seem to understand this thing. You only get tiny amounts in thrust, but with no friction and only microgravity just a tiny bit of continuous thrust will get you moving really fast, but getting up to speed takes a while.
You're not going to defeat gravity with one of these.
And the only environmental hazards would be your source of electricity, since this drive doesn't leak anything. Before you get a hoverboard out of this, you're going to have to have the equivalent of a municipal power plant or more in its batteries.
mcgrewbooks.com mcgrew.info nooze.org
(Score: 2, Interesting) by Anonymous Coward on Tuesday November 22 2016, @06:44PM
FTFY. The very fact that it thrusts, together with the very fact that space is homogeneous, strongly suggests that there is something leaking out, even if we don't know what it is.
Maybe this drive actually exhausts dark matter. Can you exclude that possibility? (Well, if it does, I'd expect the exhaust to be harmless — but the only way to know is to test.)
Of course as long as it is only useful in space, the exhaust doesn't really matter. I don't think many people care about polluting interplanetary space.
(Score: 1) by Demena on Tuesday November 22 2016, @11:43PM
Sorry but you appear to be in error. Consider the thrust produced by the Casimir effect. No radiation. The "EM" drive is a Hubble scale Casimir effect. It is relying on radiation (Unruh radiation) that is already there.
What I like is what it does for Mach
(Score: -1, Troll) by Anonymous Coward on Wednesday November 23 2016, @06:17AM
"Consider the thrust produced by the Casimir effect."
Nazi CIS white male bullshit.
Probably want to rape young girls too.
AOC should be 25, fucking white males.
(Score: 3, Interesting) by takyon on Tuesday November 22 2016, @06:59PM
Maybe you haven't read around. The inventor is claiming to do just that - defeat gravity - with the second generation of emdrive.
If one version of his devices produces anomalous thrust, the newer claims should at least be taken seriously.
I'm still waiting for the paper that disproves the first iteration of emdrive. Now we have a peer-reviewed vacuum test.
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
(Score: 2) by mcgrew on Wednesday November 23 2016, @02:43AM
Well, if and when, then I'll have Dewey's ships upgrading from the terrawatt ion drives.
mcgrewbooks.com mcgrew.info nooze.org
(Score: 2) by takyon on Wednesday November 23 2016, @04:33AM
*terawatt [wikipedia.org]
sexy though
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
(Score: 2) by mcgrew on Friday November 25 2016, @02:04AM
I hate typoos!
mcgrewbooks.com mcgrew.info nooze.org
(Score: 2) by JoeMerchant on Wednesday November 23 2016, @03:42AM
Yeah, that theory is a bit farther out there, but having already knocked one set of "known physical laws" on their ear, we should at least give the guy some funding to work on his next idea - no matter how wonky it seems.
🌻🌻 [google.com]
(Score: 0) by Anonymous Coward on Tuesday November 22 2016, @06:21PM
but I know I wouldn't want BTTF-style flying cars & hoverboards buzzing about over my head until I knew they weren't going to give me cancer or catastrophically poison the environment somehow.
I think gravity and unanticipated crainial displacement should be your primary concern.
(Score: 0) by Anonymous Coward on Tuesday November 22 2016, @05:19PM
Color me underwhelmed. For starters, I'm not going to run out and open my wallet based upon their Figure 19. The best possible outcome, in my mind, for these guys, is that this attracts enough attention for it to be tested by people who know what they're doing. This paper still keeps it at the cold fusion level and I'm sure, just like with cold fusion, there could develop a whole slew of garage labs (both literally, as well as the "using borrowed equipment and doing it on my own time at night at a research institution" like "Eagleworks") that pop up "confirmed" or "suggestive" results that will linger for decades.
(Score: 3, Interesting) by bd on Wednesday November 23 2016, @01:53AM
Fig. 19 is not that bad, considering they have a good explanation for it. They had thermal issues (the cavity changing shape and size)
due to the heat sources in a vacuum and those get worse when they increase power. They really should have motorized their three-stub
tuner, so that they could match the cavity to 50 Ohms while operating. Would have been like 100 $ of hardware if they bought expensive
stuff. Strange that they worked with such a shoe-string budget. They could have gotten higher power amplifiers for 50 bucks on ebay
if they were lucky... Beats me, I spend more money on my hobbies.
Or they could have, like, asked someone with serious power microwave stuff for a few hours of playtime. Guess it would be easyer to
measure the effect at 80 KW feed power as opposed to 80 W...
What really makes me sceptical though, is why this is not observed at optical frequencies.
For example, mode-locked disk lasers routinely have several orders of magnitude more energy in their cavities than this glorified
80 W microwave oven. Like, Gigawatt pulse powers and tens of kilowatts average. And beam diameter varies at the end mirrors,
just like the tapered waveguide expands.
Why do pulsed lasers then not disturb other experiments on the optical table, such as interferometric experiments?
(Score: -1, Troll) by Anonymous Coward on Wednesday November 23 2016, @02:03AM
"Color me underwhelmed. For starters, I'm not going to run out and open my wallet based upon their Figure 19. The "
No one's asking you to, cunt.
(Score: 3, Interesting) by JoeMerchant on Tuesday November 22 2016, @05:47PM
To me, EM drive isn't about competing with solar sails, EM drive is about utilizing a plutonium pile vs a dark-side radiator plate to generate electricity for thrust. If you're "headed into the dark" and don't want to radiate heat against your acceleration, radiate to the sides instead.
Long ago, I heard a reasonable explanation of why the EM drive might not "break physics" having to do with relativistic properties of the microwaves changing in the chamber so that they struck one side and reflected at a different relativistic state (fraction of the speed of light) than the other side - so, from the wave's perspective it's bouncing back and forth equally, but from the chamber's perspective, it's hitting one side harder than the other.... Yes, this is oversimplified like explaining relativity with a rubber sheet and a bowling ball, but I think the world needs a NdGT level explanation of things like this to help people get their heads around it, instead of always presenting it as "breaking all known LAWS of Physics."
🌻🌻 [google.com]
(Score: 0) by Anonymous Coward on Tuesday November 22 2016, @06:47PM
Why not to the back? In the worst case, it has no non-negligible effect at all, and in the best case, it adds to your thrust.
(Score: 2) by JoeMerchant on Tuesday November 22 2016, @07:44PM
If you're headed "into the black" the back side would be solar heated, decreasing the efficiency of the radiator - lower temperature differential with the Plutonium pile means less useful energy captured.
🌻🌻 [google.com]
(Score: 0) by Anonymous Coward on Tuesday November 22 2016, @07:46PM
That would be cool of Roger called a press conference, and said, "I've prepared a demonstration to address the skepticism surrounding our new drive."
He pushes a button on the arm of his chair, and the chair floats up and buzzes around, over the heads of the reporters.
(Score: 0) by Anonymous Coward on Tuesday November 22 2016, @08:22PM
I see many going "no it can't work _because_ the theory says it can't" or "it can't work because the claimed theories behind it don't make sense" which is actually very unscientific.
I'm assuming the NASA isn't conducting a fraud so at worst there could be experimental errors. But even if it doesn't work in space, if the actual effect is significant in other scenarios someone might be able to find another use for it.
It's just like the Cold Fusion stuff. A lot of scientists and people went unscientifically crazy _against_ it. Even if it wasn't fusion, "cold fusion" could be an interesting and novel way of storing energy. It might not be practical or useful at the moment but lots of scientists study stuff that's useless with no practical application. But no many went against it as if someone had just insulted their religion. The theories and claims could be wrong, but as long as the phenomena is real, there's potential for science to be done.
(Score: 0) by Anonymous Coward on Tuesday November 22 2016, @09:33PM
I'm assuming the NASA isn't conducting a fraud so at worst there could be experimental errors.
At least read the abstract. 1.2 +- 0.1. That's well outside any errors. And these numbers match whether it was tested in air or in vacuum.
If currently it can't be explained (AFAIK), maybe we are getting EM gravity angle for some reason?? That would be just awesome.
But no many went against it as if someone had just insulted their religion.
Seriously, dude, you don't know how science works, do you? Extraordinary claims require extraordinary proof. Which means repeatable, correctly done experiments. Now first experiments were done. See the number above. It's no more extraordinary claims. What we have is something that is interesting that has to be explained. Which is actually exciting. Now let's see if real scientists can actually explain it :D
Scientists, like most people, don't like to have their chain yanked by quacks, which actually happens over and over and over again. Just search the internet for "zero point energy" and other bullshit that doesn't take more than elementary physics to show to be wrong. Anyway, getting off track....
Hopefully exciting months ahead!
(Score: 1) by Demena on Tuesday November 22 2016, @11:47PM
MiHsC seems to cover it. Not old science or new science but ignored science.
(Score: 0) by Anonymous Coward on Wednesday November 23 2016, @11:45AM
But I want a zero point energy manipulator. On second thought, screw that. I want an ASHPD. That would cut down on my travel times a lot.
(Score: 0) by Anonymous Coward on Wednesday November 23 2016, @05:10PM
Seriously, dude, you don't know how science works, do you? Extraordinary claims require extraordinary proof. Which means repeatable, correctly done experiments.
When a phenomena is newly discovered and poorly understood, it's not always easy for others to reproduce it. Doesn't mean it's not real.
And from what I recall lots of people (even on the sceptic side) managed to reproduce the suddenly heating up bit of the cold fusion stuff. That bit was repeatable. They just didn't see any "net energy gain". e.g. the heating up heat was not more than the energy they supplied. So it should have been clear that it was not like any of the quackery stuff - there was an actual new phenomena. Whether that phenomena matched what P and F claimed was a separate issue.
See also: https://www.technologyreview.com/s/402679/is-cold-fusion-heating-up/ [technologyreview.com]
The physics establishment continues to scoff, but some scientists who have been watching the field carefully are convinced something real is happening.
The scoffing isn't scientific. And that's a fairly accurate description of what the establishment has been doing- scoffing instead of science.
(Score: 2) by Geotti on Wednesday November 23 2016, @02:28AM
although solar panels won't be ideal for some journeys.
Why would you use solar panels, if you can have it nuclear-powered and thus independent of external power sources?
(Score: 2) by takyon on Wednesday November 23 2016, @04:29AM
Compact fusion on a spacecraft would be great. There are also designs for fusion rockets that are similar to ion engines. RTGs have some problems, and fission reactors would run out of fuel somewhat quickly. Both of those have the risk of spreading radioactive material if the ship blows up in Earth's atmosphere. However, if an emdrive (2.0) that can counteract gravity was used, the ship could ascend slowly and more safely than any chemical rocket.
If emdrive 1.0 and/or 2.0 are successful, then it will be the time to figure out how to power it.
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(Score: 0) by Anonymous Coward on Tuesday November 22 2016, @03:39PM
...so long as they're fitted with noise makers. This needs to be a law!
(Score: 1, Touché) by Anonymous Coward on Tuesday November 22 2016, @04:02PM
In space, nobody can hear you drive.
(Score: 0) by Anonymous Coward on Tuesday November 22 2016, @04:21PM
I, for one, welc - THWOMP!
(Score: 0) by Anonymous Coward on Tuesday November 22 2016, @10:14PM
What's the coolest movie spaceship sound?
How about mixing together a jet engine starting up, Forbidden Planet-ish 50's sci fi sounds, and a bass throbbing sound, kind of "wumm wumm wumm wumm...", increasing the tempo but not the pitch as the engine warms up.
And put neon blue-purple lights coming out of one end, and throbbing Tron-like blue-green light patterns around the outside surface.
And a stage-mist sprayer for a slight engine exhaust haze.
Even if it failed to fly, people would still be going "oooh, aaaaah!"
(Score: 3, Interesting) by VLM on Tuesday November 22 2016, @03:46PM
This ALMOST but not quite sounds like something I could do in my basement.
Weird as hell waveguide, essentially, check, got a full (small) metalworking shop
A bit under the ham radio 2 GHz band, check. I think their work is below waveguide WR340 cutoff, I'll have to use WR430 size, I'm sure the similarity in name won't totally confuse the hell out of people, LOL. Or WR510 probably better yet.
40 60 80 watts at 2 GHz, check, not a problem, how about some 200 watt-ish Spectrian rack mounts? 40 watts aint nothin, would have been impressive when I was a kid and hams still thought 6146 vacuum tubes were cutting edge technology, but not so much today. My dad actually built a sideband HF transmitter that used a pair of 6146 tubes...
Glances at the paper abstract, a fraction of a KW should provide... a couple milligrams of force? Um that ain't getting measured in my basement, naw. And I'm not going to be building a "jet pack" out of that technology with anything less than a nuclear power plant tethered to my ass by a giant power cable (well, roughly, if I'm many thousands of grams and the force is thousandths of grams thats at least a factor of millions and nuke plants output millions of KW so forces that would shove me around at modest G force would requite gigawatts)
I can see why, if its all legit, nobody noticed the almost infinitely small forces involved before. I can see why microwave towers I worked with/at did not get tipped over by the tremendous thrust LOL. Or NOAA wx radars or ATC.
(Score: 2) by bradley13 on Tuesday November 22 2016, @03:57PM
The thing is: if this pans out, optimization will "only" be a engineering problem. You just have to machine that waveguide to maximum the quantum effects.
Consider any ground-breaking technology: a couple of orders of magnitude improvement in efficiency would be entirely normal. We could be living in exciting times - here's hoping!
Everyone is somebody else's weirdo.
(Score: 3, Informative) by takyon on Tuesday November 22 2016, @04:00PM
Here's some elaboration on how much the technology "could" be improved:
https://soylentnews.org/comments.pl?sid=15357&cid=397782#commentwrap [soylentnews.org]
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
(Score: 3, Insightful) by VLM on Tuesday November 22 2016, @04:16PM
Hmm tons of force that sounds a bit outlandish. Imagine a (formerly) hydraulic press powered by a COTS microwave magnetron instead.
Something about that sounds wrong like someone would have noticed in an accident at a transmitter site in the past, oh whoops a bird landed on the feedhorn and the tower flipped over due to the forces involved, etc. I made a serendipitous mistake hooking up the microwave waveguide and the system grenaded and took out the whole floor of the lab, that kind of thing would tend to get noticed historically.
(Score: 2, Interesting) by Demena on Tuesday November 22 2016, @11:59PM
It has been noticed. Casimir effect. Changes in orbits sometimes add velocity. Lots and lots of really little things - and lots of Hubble scale effects to. Check out MiHsC
(Score: 3, Informative) by VLM on Tuesday November 22 2016, @04:57PM
"only" be a engineering problem
There are some basic physics problems to solve such as a given dimension of waveguide can only carry X amount of power which even lowly humans decades ago could generate resulting in flash over inside smaller waveguide sizes. You can pull a hard vacuum (good luck maintaining that) or pump in sulfur hexaflouride or whatever, there's a really heavy decent dielectric gas that might gain you a factor of less than 10 of voltage. Or operate at high pressure, more atoms in the way of the big spark. Going higher freq means lower efficiency RF sources and smaller apparatus that flashes over at lower power. So higher freq is out.
Meanwhile you can't just cheat and go low in frequency because first of all it gets big and really heavy really fast and the skin effect of conductors means at some power level if you don't cause a spark between voltage maximas you'll be conducting so much RF current in current maximas thru such a thin layer that you'll vaporize some off and obviously nothing conducts between voltage maxima better than air saturated with vaporized copper so things rapidly go downhill fast. Red hot waveguide is a non starter at current technology levels.
Another second reason you can't cheat and go low is the ole surface area to volume ratio that at a fixed KW per unit volume its harder to cool something big than something small.
Of course you can abandon single mode operation and run multimode. That is a lot of fun to model and control, like fusion research level of fun and games. But its at least theoretically possible? There is a certain interesting symmetry that fusion power plants try to control and maintain a plasma when pumping a GW thru a giant ass waveguide, while this EM drive thingie would seem to also pump a GW thru a giant ass waveguide while NOT creating or maintaining a plasma discharge. Both are kinda difficult and on bad days at work would likely wish they worked at the opposite facility!
So in summary unfortunately electrical engineering is advanced enough that we're already operating near-ish basic material limits as understood by the physicists. Its quite easy to arc over a coaxial cable for example, and mankind hasn't invented the materials that a sufficiently lazy engineer or tech can't arc over. I've also melted cables while doing stupid things and yes you can "in theory" replace that low melting temp polyethylene foam or whatever with something like titanium oxide or beryllium oxide but those are a PITA to work with.
(Score: 2) by bradley13 on Tuesday November 22 2016, @06:48PM
At the moment - assuming the effect is real - the device is at the stage of using a flame thrower to light a candle: lots of power for very little effect.
My rough understanding of the device is that the geometry of the chamber is what causes the quantum effects. Assuming that this is the case, it may be possible to refine that geometry to increase the proportion of photons that experience the effect. It may be that no increase in power is required to achieve increased thrust.
Or this may be cold fusion all over again. There's no way to tell for sure, except through further experiments.
Everyone is somebody else's weirdo.
(Score: 2) by takyon on Tuesday November 22 2016, @03:58PM
Yeah, better ramp that power up to about 5 kW. No vacuum needed!
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
(Score: 0) by Anonymous Coward on Tuesday November 22 2016, @04:32PM
We've got the power source. [extremetech.com]
(Score: 3, Interesting) by takyon on Tuesday November 22 2016, @04:35PM
http://www.lockheedmartin.com/us/products/compact-fusion.html [lockheedmartin.com]
https://en.wikipedia.org/wiki/Lockheed_Martin_Compact_Fusion_Reactor [wikipedia.org]
http://www.defensenews.com/story/defense/innovation/2016/05/03/lockheed-nuclear-fusion-generator-investment/83870398/ [defensenews.com]
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
(Score: 4, Interesting) by VLM on Tuesday November 22 2016, @03:57PM
optimal thrust was present if the system had a quality factor of at least several thousand
Replicate with superconductive material at liq helium temp. Because dumping 80 watts of RF into heat would be an epic engineering challenge at liq He temps (LOL) and even if you can only pulse it for a few milliseconds at a time, the Q of a superconductive resonator should be pretty high.
Assuming that resonance isn't just coincidental at peak thrust etc.
(Score: 2) by fubari on Tuesday November 22 2016, @06:09PM
VLM, +1 for combining "liquid helium" and "LOL" in a single sentence. First time I recall seeing that :-)
epic engineering challenge at liq He temps (LOL)
What do you do for your day job?
I follow the rough ideas of what you say, and am amazed you conceive of such things just because they seem like fun.
Thank you for sharing (really!) :-)
Now just out of curiosity, why liquid helium vs. liquid nitrogen super conductors?
(Score: 4, Interesting) by VLM on Tuesday November 22 2016, @09:25PM
Because the liq N2 superconductors are all annoying ceramics that have to be shaped and fired and are brittle (last time I checked) but the liq He superconductors are just boring old metals. Weird metals, but still, just metals. There are some non-fun limits to current and magnetic fields for high temp conductors too.
Whats not funny is liq He has very low heat of vaporization, you look at it funny and a liter boils off at like $10/liter. Its not like water where boiling takes like 600 degrees of heat or whatever it is exactly. So the idea of boiling off Liq He at 100 watts rate is kinda funny, someone has way too much money to be doing something like that...
(Score: 2) by Flyingmoose on Wednesday November 23 2016, @02:33AM
But wouldn't the superconductor stop it from boiling? I mean MRI machines have huge amounts of current running through them...
(Score: 2, Interesting) by Scruffy Beard 2 on Wednesday November 23 2016, @06:29AM
A neighbour was asking about a super-conducting flywheel one time (using electrons to store momentum).
I found the super-conduction stops under high magnetic field strengths.
Random wiki article [wikipedia.org]
(Score: 0) by Anonymous Coward on Tuesday November 22 2016, @04:05PM
Would this type of engine only work in space, or could you also use it on earth (e.g. on an aircraft or (hover)boat)?
(Score: 2) by MrGuy on Tuesday November 22 2016, @04:18PM
Short answer? Yes, but no. You could use it, but it's incredibly inefficient.
The amount of thrust is INCREDIBLY small. The devices being tested have thrust measured around 0.001 Newton per kilowatt of power. That's about enough thrust to life a grain of rice off a table, for a kilowatt of input power. That's many, many, many orders of magnitude less force than you'd get with an electric motor.
The big deal here is that this is force we can get in a vacuum, without propellant. The need to carry (and eventually exhaust the supply of) propellant is one of the hardest problems in rocketry. So the ability to generate thrust without carrying around propellant is a huge advance.
(Score: 2) by VLM on Tuesday November 22 2016, @05:12PM
That's about enough thrust to life a grain of rice off a table
If you could project that force or field, its interesting to consider that a commercial success on the ground might be a force thats un-noticable to anything bigger than a butterfly but covers an area the size of a back yard patio with a force stronger than a mosquito can fly against. Or a force that pisses off mosquitos so they fly away.
You can just use an electric fan like we did when we were kids and those keep the bugs away and on a hot summer night they keep you cool out on the deck/patio probably for less electrical power but a no moving parts gadget might sell to Dyson type customers.
Also you could make a tiny little hole in the thruster's waveguide and provide a couple KW so the kids could roast marshmelons (what maybe 1% of SN is going to get that reference? Thats an old movie now...)
(Score: 2) by MrGuy on Tuesday November 22 2016, @06:02PM
Yeah, but now you're talking about a completely different theoretical device.
One of the things that has people so flummoxed about this device is that it appears to produce thrust with no exhaust. It appears to violate conservation of momentum. So, there's no "force" from the exhaust to use like this.
Even if you did have a useable exhaust force, this method is an incredibly inefficient way to generate it. You're much better off using a physical device like a fan to produce the effects you're describing.
(Score: 2) by VLM on Tuesday November 22 2016, @09:26PM
Yes but it would be really, really cool...
(Score: 0) by Anonymous Coward on Tuesday November 22 2016, @04:24PM
Anywhere you can turn it on. But low thrust means space is likely where it would be useful.
(Score: 3, Funny) by DannyB on Tuesday November 22 2016, @04:31PM
What about practical low thrust applications on Earth, such as keeping ghosts out of your house?
(ducks, hides under desk)
The lower I set my standards the more accomplishments I have.
(Score: 0) by Anonymous Coward on Tuesday November 22 2016, @06:51PM
I'm pretty sure the desk doesn't protect you from ghosts.
(Score: 2) by takyon on Tuesday November 22 2016, @04:30PM
The version NASA is testing is comparable to an ion engine capable of making a sheet of paper flutter at best. Roger Shawyer claims that the second generation of emdrive would make a hovering electric vehicle possible:
http://www.ibtimes.co.uk/emdrive-roger-shawyer-paper-describing-space-propulsion-uavs-finally-passes-peer-review-1513223 [ibtimes.co.uk]
http://www.ibtimes.co.uk/emdrive-exclusive-roger-shawyer-confirms-mod-dod-interested-controversial-space-propulsion-tech-1586392 [ibtimes.co.uk]
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
(Score: 3, Interesting) by VLM on Tuesday November 22 2016, @04:11PM
If I did my math right (LOL) and if you skip the idea of a rocket engine and go for sound speaker, and you make the construction extremely light, I think the forces would be measurable although inaudible to human ears in a top quality anechoic sound chamber at sane-ish power levels. Feed in an AM modulated signal instead of CW and there you go, the worlds most exotic speaker. So it won't be replacing car subwoofers any time soon, but it should be able to almost generate audible (well, in theory) sound. Quiet sounds don't require much force.
This would explain why no level of casual screwing around in the microwave RF lab results in sounds, not just no movement. Just at the border under ideal conditions of almost making a sound before it melts.
Which is creepy because there's no reason it has to be that close in the physics, why not 1e-24 times too low. That could indicate scam like someone reverse engineered why a microwave RF lab can be silent yet the effect exist then worked backwards. Then again everything new that's discovered has always been just outta the noise level, just at the border of possible.
(Score: 2) by quintessence on Tuesday November 22 2016, @04:59PM
I had read they are making microphone transducers out of graphene. Only a skip and a jump to speakers. Just insane having a near translucent cone that strong.
Anyhoo, the transducer should be able to pickup even the slightest perturbation in the air. Even if not audible, it can be measured.
(Score: 2) by VLM on Tuesday November 22 2016, @05:06PM
Yup there you go. A graphene microphone and a graphene disk with the thruster attached as if a speaker cone. Maybe make the whole thruster out of graphene.
Stuff like slow thermal expansion should average out if you feed an ultrasonic 100 KHZ AM modulation of microwave power into the thruster, and the microphone should just barely be able to hear it.
Now good luck dumping kilowatts to megawatts into one thing and having no capacitance affecting the electronic transducer.. which is where the true brilliance comes in with this design, look at the phase of what you transmit vs what you hear because sound is immensely slower than light (microwave RF) so the signal you're wanting to listen to syncs up after sound travels 5 feet not after light travels 5 feet. You can subtract any signal that syncs up after light travels 5 feet. Heck you could hook up a white noise source to the thruster and correlate sonar style that the microphone heard sound from 5 feet ago, or 5 feet away, however you want to look at that..
(Score: 3, Informative) by JoeMerchant on Tuesday November 22 2016, @07:49PM
All too easy for the power cables to generate audio as the signals they carry modulate... the magic here is thrust without mass, it's not a big deal when you're swimming in mass, sucked down onto a giant ball of mass by its gravity... it becomes a big deal fast when you leave that gravity well.
🌻🌻 [google.com]
(Score: 2) by Scruffy Beard 2 on Wednesday November 23 2016, @06:32AM
You do get coil whine. The coils change shape slightly when you run current though them.
(Score: 0) by Anonymous Coward on Tuesday November 22 2016, @04:19PM
Can we please have all the extremely vocal naysayers actually admit that they were narrow minded fools disregarding things they barely understood?? Of course not... denial seems to be intimately tied to the human condition.
(Score: 2) by WillR on Tuesday November 22 2016, @04:57PM
(Score: 0) by Anonymous Coward on Tuesday November 22 2016, @05:03PM
Ya about what I expected. The EM drive was much different from the thousands of weird pet theories on the net, people actually did experiments with positive results. Also, I wasn't talking to the skeptics who think it is unlikely but are interested to see what comes of it... I'm talking about the rabid "that violates XYZ and is obviously garbage". I'm hoping here that some people realize their deep held beliefs can be wrong, and that they start applying such critical thinking to all aspects of their lives.
But as you point out, most will turn to such statements as yours to validate their thought processes (not that you were one of the vocal naysayers).
(Score: 2) by tangomargarine on Tuesday November 22 2016, @06:36PM
It's a question of pragmatism. You can safely ignore people whose theories violate the known laws of physics 99.9% of the time, and allocate the time you would've spent debunking it doing something else more productive.
people actually did experiments with positive results
As far as I'd heard until now, nobody had done the experiments and obtained statistically significant positive results other than the original guy. Positive results within the margin of error of measurement != positive results.
"Is that really true?" "I just spent the last hour telling you to think for yourself! Didn't you hear anything I said?"
(Score: 1) by WillR on Tuesday November 22 2016, @07:35PM
And I'm fine with people reading that as validating their "if it appears to violate conservation of mass/energy/momentum, it's probably measurement error or a scam" thought process, because it's still a useful filter for all the free energy bullshit out there.
(Score: 0) by Anonymous Coward on Tuesday November 22 2016, @08:05PM
Gotcha, I'll just take the lesson that narrow minded folks are self-reinforcing. I expected better from this crowd, but I guess the genie is out of the bottle. When NASA got involved it became time to shut up with the "obviously will never work it violates conservation laws!" I get annoyed when a bunch of techies look at physics type stuff and assume they are more intuitively correct than NASA. Perhaps NASA involvement means its time to put on the skeptic hat instead of the authoritative hat.
As with most things in life it is better to be skeptical instead of absolute, the latter leads to rigid thought processes that prevent growth. Since you seem to have a thing for science you should understand the value of definitive proof, guesses and assumptions are terrible methods of finding a conclusion. If you can't grasp that concept then please don't comment on things unless you're willing to actually research with an open mind.
For a more relevant metaphor: RTFA before you comment!
(Score: 2, Insightful) by WillR on Tuesday November 22 2016, @09:29PM
(Score: 1, Informative) by Anonymous Coward on Tuesday November 22 2016, @10:12PM
You just plain and simple miss my point. I was never accusing you since this is the first time I've discussed the EM drive with you. I was an optimistic skeptic, based on what I read I thought there was potential for this to be real (yay confirmed, now for useful versions...) My commentary is aimed at all the people that dismissed it because they did little research and couldn't get past the no propellant issue. Besides, there actually is propellant, pure energy!
There is no free energy (barring spiritual "let there be light" type stuff) and even the quacks that think they're getting free energy from magnets could be on to something. Not free energy, but quenching a magnet over a long period of time could be a decent type of "battery", haven't done any calculations about energy density so don't know if that would be useful but whatever. You never know where something interesting might pop up, it could be surrounded by lots of quackery but that doesn't mean there isn't SOMETHING there.
Put in whatever effort you'd like, but dismissing something without actually engaging the topic and teasing out the bullshit from the facts is just intellectual masturbation to make yourself feel good. Also, we can miss major scientific breakthroughs with such thinking. For another good example: Snowden and his revelations about mass surveillance. Ten years ago you were a crackpot for saying all the governments were spying on literally everybody. Now it is just accepted as fact. Again, I'm not saying you should believe every crackpot theory, just don't approach things with a closed mind (meaning you already know the "answer"). I was educated in physics, I read the early reports years ago, and the idea was that the reflected photons lose momentum in one direction only. I saw no inherent reason why this couldn't work so I gave it cautious optimism. Everyone else stopped at "no propellant, no easily understood momentum transfer, QUACKER!" Height of hubris.
(Score: 0) by Anonymous Coward on Thursday November 24 2016, @06:10PM
Unless you are actually working in a related field, or are responsible for funding decisions that may affect research on it, your thinking about it has exactly zero effect on the progress of science.
What I think about entanglement-related stuff does have an effect on the progress in the field (at least I hope so), because that's the field I work in. What I think about EmDrive or the theory behind it is completely irrelevant to the progress of science, as I'm not working in that field.
What matters is not what I, or probably anybody on Soylent News thinks. What matters is what NASA did: Actually test the thing. If the tests continue to be positive, you can expect the theory to gain traction. That's how science works.
Scepticism is at the heart of science. Don't believe it, test it. The day when people no longer distrust new theories is the day that science has died.
(Score: 2) by JoeMerchant on Tuesday November 22 2016, @07:51PM
I wouldn't expect apologies until after the first demonstration spacecraft has flown, and even then, not complete acceptance - there will be "flat earth" theorists as long as there are people who don't travel enough to experience the curvature of the earth.
🌻🌻 [google.com]
(Score: 2) by tangomargarine on Tuesday November 22 2016, @06:32PM
"Narrow minded fools" to believe the laws of physics, yes. How silly of us.
"Is that really true?" "I just spent the last hour telling you to think for yourself! Didn't you hear anything I said?"
(Score: 2) by takyon on Tuesday November 22 2016, @07:00PM
Laws were meant to be broken.
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
(Score: 2) by turgid on Tuesday November 22 2016, @10:56PM
Jon Bon Jovi, is that you?
I refuse to engage in a battle of wits with an unarmed opponent [wikipedia.org].
(Score: 0) by Anonymous Coward on Tuesday November 22 2016, @08:32PM
Substitute "laws of physics" for "laws of god" and you can go persecute Galileo!
Seriously, this is the problem. If you want to deal with fringe theories then you have to be comfortable wading through dubious scientific theories and giving them some critical thought. If you just adhere to "violates the law" then you're just looking to reinforce your intellectual superiority.
THAT is what I have been trying to address in this thread, but as you make clear some people are comfortable in their worldview because it makes them feel secure "knowing" the truth. It is much like religious believers, they need something to believe in so they can continue about their day to day and thus they persecute anyone who says differently. At least with scientific theories, and the scientifically minded, its possible to get a more objective truth and most scientists will acquiesce once that objective truth is proven.
(Score: 0) by Anonymous Coward on Tuesday November 22 2016, @10:01PM
There are TWO problems with existing test results. First is that they appear to violate the known laws of physics, and second the results are very weak such that undiscovered testing errors could still very well be a factor. These together warrant a lot of skepticism. If one or the other didn't exist, it might be a different game.
For example, if the force was so strong that the device launched itself off the table, then most agree more experimentation is immediately warranted regardless of whether it seems to violate known laws.
(Score: 0) by Anonymous Coward on Tuesday November 22 2016, @10:18PM
I'm fine with skepticism, its the outright "this is stupid it violates conservation" comments I'm talking about. Skepticism == good, absolute decrees == bad (until evidence supports it). This could still turn out to be nothing, though with this paper that seems unlikely.
TL:DR for this thread: don't leap to conclusions, this isn't psychology :P
(Score: 0) by Anonymous Coward on Tuesday November 22 2016, @09:10PM
Trump? I'm still highly puzzled.
(Score: 2) by DannyB on Tuesday November 22 2016, @04:23PM
Would you need a solar panel as large as a space sail? Nonetheless, it would be two orders of magnitude more efficient.
According to Wikipedia
https://en.wikipedia.org/wiki/Sunlight [wikipedia.org]
you get 1367 watts per square meter, in space, at 1 AU. (Earth-Sun distance.)
Since that's just over 1 KW, that gets you somewhere in that 3 to 6 micro newton thrust range.
Increase KW and thrust by adding more square meters of solar panel.
But, then how efficient are the solar panels? Surely you don't get 1367 watts per square meter out of a solar panel. So just how big a panel to you need?
If this decreases as the square of the distance, then at 2 AU you need four panels to get the same power as 1 panel when you started out the journey at 1 AU. But by the time you are at 2 AU, you would have a greater velocity than when you started at 1 AU.
Or would it be better to use RTGs? (Radioactive Thermoelectric Generators, the kind of things like on on Curiosity, and deep space missions like New Horizons.) With RTGs you don't need a "sail" (or sale) of solar panels.
Can you place this engine anywhere in the spacecraft? Does it have to be at the "tail" end like an engine that expels particles to provide thrust?
The lower I set my standards the more accomplishments I have.
(Score: 2) by DannyB on Tuesday November 22 2016, @04:28PM
> Since that's just over 1 KW, that gets you somewhere in that 3 to 6 micro newton thrust range.
I realize I was using the wrong number here. That's the thrust of the competing technologies. (solar sales, etc)
This is 1.2 milli-newton per KW.
Wouldn't that be THREE orders of magnitude more thrust, or do I misunderstand something?
https://en.wikipedia.org/wiki/Order_of_magnitude [wikipedia.org]
"Orders of magnitude are written in powers of 10."
The lower I set my standards the more accomplishments I have.
(Score: 2) by inertnet on Tuesday November 22 2016, @10:08PM
1.2 milli is 200 to 400 times 3 to 6 micro, so 2 orders of magnitude.
(Score: 3, Interesting) by VLM on Tuesday November 22 2016, @04:30PM
I ran another creepy or bad or maybe good set of numbers and if you built a somewhat bigger version and bolted it to the ISS with a realistic amount of solar power, it would just be in the noise of accepted noise level of ISS orbital parameters. If you could get ten times the power out the panels with the same weight or area they'd already have done it (cost is no object). The ISS orbital parameters are always changing a little and its always slowly re-entering and needing boosts but at an even lower level there's just random noise from the thing like thermal radiation or whatever, and the drive as reported isn't quite powerful enough to bolt on, power up, and show a statistically noticable provable kick in the graphs. Close but not there.
Again, either exciting that its close, or if its a scam the quy who put the scam together really did his physics to max out the result without making it too obvious and too easily testable. Its inconclusive to a peculiar same level as my theoretical speaker experiment.
(Score: 0) by Anonymous Coward on Tuesday November 22 2016, @06:03PM
First good news since the election. Sulu, away, warp factor 11!
(Score: 0) by Anonymous Coward on Wednesday November 23 2016, @04:10AM
If you're going above warp 10 you need an alien and some serious meditation to make sure your mind is focused....
Silly nerds deliberately being silly
(Score: 0) by Anonymous Coward on Tuesday November 22 2016, @06:06PM
Put it on something isolated in space and see if it accelerates.
(Score: 3, Funny) by bob_super on Tuesday November 22 2016, @06:30PM
Trying that, but spherical cows are back-ordered.
(Score: 2) by JoeMerchant on Wednesday November 23 2016, @03:49AM
The Holstein spherical cows are available, but nobody wants to do the math - we're waiting for homogeneously colored spherical cows.
🌻🌻 [google.com]
(Score: 2) by takyon on Tuesday November 22 2016, @07:02PM
If it produces enough thrust, it doesn't need to be tested in space. Ion engines are tested on Earth, vacuum or no vacuum, without issue. Stop repeating that meme.
You might get your wish anyway from Cannae Inc. [soylentnews.org]
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
(Score: 0) by Anonymous Coward on Tuesday November 22 2016, @07:31PM
For business as usual, I agree that tests on the ground should be sufficient.
Ion engine don't violate our understanding of physics.
This gadget appears to.
For that, experiments on the ground still leave too many claims of possible instrumentation error.
I think this one is worth a better experiment that eliminates as much possible error as can be done.
It might be a lesson in we should have caught the experimental error on the ground.
It might be a lesson in basic physics.
Either way, given the experimental results to date, it seems worth the extra effort.
(Score: 0) by Anonymous Coward on Tuesday November 22 2016, @08:29PM
(Score: 2) by fritsd on Tuesday November 22 2016, @07:24PM
Years ago I read about VASIMR [adastrarocket.com] and I thought NASA was going to test it at the ISS.
Is this "EM drive" just a more pronounceable word for VASIMR, or is it a different type of microwave + shaped cavity + no electrode trellis that can be worn away?
And why haven't they tested the VASIMR yet, it sounded well promising for use outside of geostationary orbit, and it has been built and tested on the ground years ago.
(Score: 3, Informative) by butthurt on Tuesday November 22 2016, @10:31PM
VASIMR creates a plasma, which is expelled. This appears, so far, to have no reaction mass.
(Score: 2) by JoeMerchant on Wednesday November 23 2016, @03:52AM
It seems to me that everybody is getting worked up about "no mass" - but didn't Einstein make this famous over 50 years ago? E=mc2... so if we've found a way to convert pure energy to force, or momentum, maybe there's some energy to mass (perhaps and back again) conversion operation at work?
🌻🌻 [google.com]
(Score: 4, Interesting) by butthurt on Wednesday November 23 2016, @05:33AM
Pure energy--light--does indeed have momentum and exerts a force, called radiation pressure. That is how a solar sail works. Microwave radiation is a kind of light; if that were leaking from the device, it could explain the force that's observed. However, the experimenters checked for that and didn't find it happening. That leaves open the possibility that the force is caused by a hitherto unknown mechanism. That is interesting, as is the possibility that forces generated with this device could exceed (for the same power) what we'd expect from radiation pressure.
https://en.wikipedia.org/wiki/Radiation_pressure [wikipedia.org]
https://en.wikipedia.org/wiki/Solar_sail [wikipedia.org]
(Score: 0) by Anonymous Coward on Wednesday November 23 2016, @09:40AM
I still think there's something wrong.
They're saying "we have this electro-magnetic device that will accelerate in a certain direction".
Momentum has to be conserved, so either there are photons taking away the corresponding momentum, or they don't have an electro-magnetic device.
If this article passed peer review, I would like to see the experiment replicated, but I still say it's a lot less likely they discovered some unknown field than it was for neutrinos to go faster than light a few years ago (and that turned out to be an experimental error).
The alternative: momentum is not conserved.
I personally find the concept of the bible being literally true much less disturbing than the idea that momentum is not conserved.
(Score: 2) by JoeMerchant on Wednesday November 23 2016, @02:05PM
Some previously unknown interaction between what appears to be a "normal" EM field and momentum would seem to me to be: A) less disruptive to current paradigms than FTL travel, B) much more plausible than a literal transformation of clay into a living, breathing homo sapiens (unless a billion years of evolution was left out to make the story flow better... but then there's still the rib thing.)
🌻🌻 [google.com]
(Score: 3, Interesting) by dak664 on Wednesday November 23 2016, @02:11PM
More generally, the electromagnetic interaction transfers action (4-momentum dot 4-distance) between two points in space time. Action transfer is quantized which can be described mathematically by raising and lowering operators on the number of "photons" in a field. However these photons by definition have no space-time existence and can not be detected during transit. To say the photon or field "has" or "carries" momentum is misleading, the action transfer occurs between the endpoints only.
So not being able to detect EM emission from the device would not preclude momentum transfer to some more distant region. The Aharonov–Bohm effect is an example of such a transfer through a region that contains no EM field (e.g. zero E-squared + B-squared energy).
However it seems way more probable to me there is some parasitic coupling from the power generator to the thrust-measuring device. Maybe a loose ground connection.
(Score: 2) by butthurt on Wednesday November 23 2016, @05:28PM
[...] photons by definition have no space-time existence [...]
I don't understand. There's evidence that they propagate through space. Are you saying that a resting photon can't exist?
To say the photon or field "has" or "carries" momentum is misleading, the action transfer occurs between the endpoints only.
I'm reading it as though you're suggesting that radiation pressure can only occur when there is something to absorb photos. For example, if a space traveller turns on a flashlight and points it at a nearby planet, the traveller's momentum will change, but if the traveller aims the flashlight into deep space, the traveller's momentum will be unaffected because there's no end point to receive the light. Am I misunderstanding?
(Score: 2) by dak664 on Wednesday November 23 2016, @06:12PM
Correct, the phase velocity of a massless particle is always C. The group velocity can be different through regions of varying potential.
Classically the fields do contain energy that propagates in 3 space, and your flashlight launches energy and momentum into the field whether or not it is ever absorbed by distant matter. If it *is* absorbed somewhere the event-separation of that light-like interaction is by definition zero and there can be no intervening events in the space-time manifold. If it is *not* absorbed then it seems there is nothing to enforce the quantized field. But relativistically there has to be some recipient for the action since the emission and absorption of the "photon" is the same event.
If the EM waves were propagating through some stationary ether, special relativity and quantum mechanics would probably both go away. Along with everything else, I suspect.
(Score: 0) by Anonymous Coward on Wednesday November 23 2016, @12:59AM
Same reason AC generators don't burn up anymore propels this engine forward.