Slashdot Mirror
EmDrive: NASA Eagleworks' Peer-Reviwed Paper Is On Its Way (ibtimes.co.uk)
An anonymous reader quotes a report from International Business Times UK: An independent scientist has confirmed that the paper by scientists at the NASA Eagleworks Laboratories on achieving thrust using highly controversial space propulsion technology EmDrive has passed peer review, and will soon be published by the American Institute of Aeronautics and Astronautics (AIAA). Dr Jose Rodal posted on the NASA Spaceflight forum -- in a now-deleted comment -- that the new paper will be entitled "Measurement of Impulsive Thrust from a Closed Radio Frequency Cavity in Vacuum" and is authored by "Harold White, Paul March, Lawrence, Vera, Sylvester, Brady and Bailey." Rodal also revealed that the paper will be published in the AIAA Journal of Propulsion and Power, a prominent journal published by the AIAA, which is one of the world's largest technical societies dedicated to aerospace innovations. Although Eagleworks engineer Paul March has posted several updates on the ongoing research to the NASA Spaceflight forum showing that repeated tests conducted on the EmDrive in a vacuum successfully yielded thrust results that could not be explained by external interference, those in the international scientific community who doubt the feasibility of the technology have long believed real results of thrust by Eagleworks would never see the light of day.
Underwhelmed.
I do not want your cheap brainburning drugs. They are useless for work. And I am a working man today.
Who are "Lawrence, Vera, Sylvester, Brady and Bailey"? Their cats?
Guh!
Reviw is sooooo important....
-- Make America hate again!
How does the energy efficiency of this drive compare to a normal rocket? Could this allow interstellar travel, by humans, within a normal human lifespan? What kind of reletavistic effects happen at high speed? I would assume thrust would drop as you approach C.
EmDrive: NASA Eagleworks' Peer-Reviwed Paper Is On Its Way
But we're not sure how long it'll take because we're not sure it puts out any thrust.
systemd is Roko's Basilisk.
How does the energy efficiency of this drive compare to a normal rocket?
If it works as advertised, it violates the law of conservation of energy, so its energy efficiency can be infinite.
(it produces a force with no reaction mass. Since energy is 1/2 mV^2, power is force times velocity, and thus the change in energy (per unit time) is proportional to velocity. So, if it runs at a given power level to produce a given thrust level, you can get more energy out than you put in simply be starting out in motion.)
Could this allow interstellar travel, by humans, within a normal human lifespan? What kind of reletavistic effects happen at high speed? I would assume thrust would drop as you approach C.
Well, if it violates the theory of relativity, anything could happen, I guess. Right now the thrust level quoted is micronewtons, so it would take millions of years to get up to the speed of light. But if the machine works, even at all, all bets on physics are off.
http://www.geoffreylandis.com
...but hey, it is peer reviewed by some people.
I imagine that there will be replicability tests. It's possible, but not certain, that we may have found Clarke's "space drive", a drive requiring no reaction mass. On the other hand, so many of these things have fizzled, I'm remaining VERY cautiously optimistic.
Portuguese trolling. He is insulting your parentage. Please, somebody mod down.
Someone needs to Peer-review slashdot, so article titles don't have words like: "peer-reviwed".
For me, even when there seemed to be some effect, it was simply far, far too small. Well within experimental noise - and certainly nothing you're going to propel anything anywhere with.
Yep. When part of their original paper stated "our test set up was so sensitive we could see noise due to waves in Galveston Bay twenty miles away!", my reaction was "omigod, that's a very bad thing," rather than the "wow, they made a great sensor" reaction I think they were looking for.
Well, if it violates the theory of relativity, anything could happen, I guess.
The guy ("scientist"?), Roger Shawyer, who invented it claims that it's actually due to the theory of relativity that it works.
Yes, but their test results explicitly falsified that theory. They tested this. The device (was claimed to) produce thrust whether or not it had the asymmetry that Shawyer claimed was required by his theory
...I'm not a physicist, so I can't speak to whether his explanation makes sense.
I am a physicist. His explanation makes no sense.
Not necessarily a bad thing. You can observe effects over a very long period and filter out noise statistically.
For the love of Christ, could we have the headlines peer Reviwed?
Author of this topic title should be peer reviwed. REVIWED
EmDrive: NASA Eagleworks' Peer-Reviwed Paper Is On Its Way
Ow ow ow, I think they just broke my irony meter!
"I love animals! Some are cute, others are tasty, what's not to like?" - Betsy Schroeder, Jeopardy contestant
This isn't the only way to make a reaction mass less drive. If you fire a laser it produces thrust. Light carries momentum. Not a lot so you need a big laser.
A laser thruster is not a very efficient device, but it is probably as efficient as the EM drive the way it is right now.
The new physics is very likely to be how the light escapes the cavity at one of the ends of the cavity. I've already seen a paper proposing this. The physics isn't really so new and it is more like of an application of QED explaining why it is hard to detect the escaping light.
Notice they always shove "NASA" in there as if it lends it any credibility. The truth is that anyone can rent "NASA" lab facilities. This is just another hoax. Also, it "soon will be published" in AIAA. Uh huh. Sure it will.
If you want to do some armchair physics, these forums are really interesting. https://forum.nasaspaceflight....
People are attempting to recreate the "thrust-less" momentum at home basically. Lots of skepticism, lots of optimism, but real numbers being thrown around.
We're almost past the point of whether or not it works and moving onto why it works.
Not necessarily a bad thing. You can observe effects over a very long period and filter out noise statistically.
That's assuming your noise is random.
I agree I'm still far from sold on the EM drive. I want to see it working in a vacuum, away from earth's magnetic field, and I want an explanation for the physics behind it.
Yes, the real test is to put one in space and see if it moves the spacecraft away from a ballistic trajectory in a direction consistent with its supposed thrust. Then you can start looking for "new physics" behind it. Given the tiny magnitude of the supposed effect*, i doubt any Earth-bound measurements can be convincing. Right now, this is strongly reminiscent of cold fusion.
*To quote the original paper: "Our test set up was so sensitive we could see noise due to waves in Galveston Bay twenty miles away."
I wonder if this thing is more efficient than radiating the same amount of microwaves or laser light out the back of a rocket. That is does it derive thrust resonantly with no loss of photons (other than imperfections) or is it a trade of one photon for one photons worth of impulse (same as a laser thruster).
And I also wonder how they cooled this thing. if it was in a vaccuum and power goes in then it heats up. It would heat up indefinitely if it did not radiate somehow. Perhaps the radiation isn't isotropic?
e.g. a selective absorber heated up should do the same thing right?
Some drink at the fountain of knowledge. Others just gargle.
are here: http://www.projectrho.com/public_html/rocket/reactionlessdrive.php
Space nutters are usually tech people who are uneducated in the hard sciences
Yet you don't seem to be able to discern who they are. You accused me of being a "space nutter" and I do have a background in hard science and engineering and accounting as well. I've built parts that have actually gone into space. I'm actually largely a voice of caution for those who spout overly optimistic timelines or economic absurdities regarding space travel.
You seem obsessed with that term "space nutter" like others are with hipster and you throw it at anyone who shows the least optimism about space travel. Lighten up. Someone who thinks that someday we might actually develop the technology to go to other planets or leave our solar system is just being optimistic. Nothing wrong with that even if they don't understand the technical details. It amounts to nothing more than fanciful musing. As long as they aren't hurting anyway with their day dreaming what do you care?
Yeah, space travel is an incredibly difficult problem and it will take a long time before we can do really useful things. This is not news.
A rather large majority of circuitry and electromagnetic knowledge was stumbled upon from the time period between the light bulb up to the semiconductor. I should add the models most electrical engineers were taught during that time had nothing to do with solid quantum mechanics or even correct chemistry.
I'd love to see this be a real effect, but it just sounds like cold fusion, or polywater, or homeopathy -- a tiny effect, where the more closely you examine it, the harder it becomes to see.
Then again, high-temperature superconductors looked the same way for a bit, and they have worked out quite nicely, with theory trying desperately to regain its footing as it's dragged along behind practice.
And as for fishing small signals out of large backgrounds, yes, that makes things tricky, but my working GPS receiver shows that it's not only possible but practical -- when the signal you're fishing for actually exists.
Brazilian Portuguese. And it's not insulting anyone's parents. Just some random "Samanta".
Dark matter/energy
- Cannot be seen or detected through usual means
- Speculative existence is one way to reconcile observed behavior with current mathematical models
- OMG IT'S REAL IF YOU DON'T BELIEVE BURN THE HERETIC!!!
EM Drive
- Proponents have actual physical apparatus that can be built and tested independently
- Effect is claimed to be measurable and significant
- If proven true would suggest flaws in current mathematical models
- OMG IT'S FAKE IF YOU BELIEVE BURN THE HERETIC!!!
You ever read and understood code written by physicists? Neither have they.
Google Translate: "The fucking Samanta goes away today? Bah, it was late this motherfucker. I'll put the rest of the wafer package in the trash, because I do not put my hand where this delayed puts it. If prorate will fill my mouth pereba."
Then you were reading (very likely mislabeled) fantasy. The whole point of science fiction is to embed a story within the context of plausible science. Nothing wrong with fantasy, but it isn't, and never has been, science fiction.
Between the "speculative fiction" rendering down of that specific distinction, and the marketing-driven labeling of fantasy as science fiction, and the tendency of bookstores for decades to lump fantasy and science fiction together, your experience is the rule, rather than the exception.
But there's still science fiction being written. The trick is finding it.
I've fallen off your lawn, and I can't get up.
So every single successful reproduction is due to bad science, even from NASA...
There aren't any "successful reproductions." Their work has not confirmed any of the previous results-- they have seen different things-- and other people haven't confirmed their results, at least, not to date.
So far, every new test has failed to reproduce the results of the previous tests.
http://www.geoffreylandis.com
In most of the mundane pursuits we understand, it goes to producing heat. In physics, one fairly valid viewpoint is that heat is motion, in that a "hotter" result has more motion activity going on at the particle level.
One of the reasons that perpetual motion is impossible is that within a closed system, we can't make anything 100% efficient. Typically the lost percentage wanders off in some fairly easily identifiable thermal guise.
The first thing to keep in mind is that not all energy expended does useful work.
But that's not really the problem here. the problem is that motion in space, as we understand it, depends entirely on imparting momentum to something. The only way we have practically been able to do that is to send stuff out one end of a spacecraft, which causes, due to the equal and opposite rule of newtonian physics, the spacecraft to go in the opposite direction.
But it's not really about "where does the energy go." This thing is being sold as "doesn't send stuff out one end of spacecraft" and "imparts momentum." The physics folks are looking at that claim very dubiously, because so far, there's no generally accepted science that could account for such a thing.
If it turns out to be a real effect (and I'm not saying it will), then we're going to have some new science to learn.
I've fallen off your lawn, and I can't get up.
Step 1 I have this crazy thing that seems to work in this experiment.
Step 2 That's impossible, try a better experiment.
Repeat a couple of times hasn't killed it yet.
Seems like the next, better experiment is to put it on a real space craft and see how fast they can make it go.
At some point, either a better experiment will show a flaw, or we will understand physics a little better.
On the contrary, the less random your noise is, the easier it is to filter out.
I really get tired of the whole modern age skeptic culture. Yeah, I get it that in order to learn and master science you kind of have to get interested in it. And yeah I get it that having some dummies to shoot down helps you improve your aim. But the universe isn't all dummies, and not all experimental scientists are dummies either.
At any rate, skepticism in our culture is so profoundly ingrained that even when you see people accepting a new theory they are still finding a way to shoot it down to keep themselves comfortable.
You wouldn't actually use a set of these things to push a fucking rocket around space, morons. You would put a set of these things around an axis like a chinese fire wheel, and allow their greater than 100% efficiency to spin them around the axis producing a limitless energy production in the zero gravity.
Then you would harness the power they're generating and do something like fire an incredibly silly, impossibly powerful laser and ride the equal and opposite reaction to quickly achieving absurd speeds.
"Stratigraphically the origin of agriculture and thermonuclear destruction will appear essentially simultaneous" -- Lee
Was this not recently identified as an insufficiently shielded power cable inducing thrust via the earth magnet field?
Most ACs are not even worth the keystrokes to insult them. Be generically insulted by this and ignored otherwise.
why don't they just build one aim it at uranus and fire it? the ship itself can be built out of lego for all it matters, If it moves an gets there it works, physics needs to be revised if not no worries its settled.
- mostly by people with NO CLUE! ( PhD in Physics here )
'Space Nutters' and 'DOGMA' and such are the particular terms used by psychologists, politicians, SJWs, fundamentalist religious types,
and people who either want to cause loud voices or people who are so sure they are right that they qualify for the stone-head award.
The theory here is not like anything covered below grad school physics. Being able to spell the words DOES NOT qualify you to express
an opinion on the science. Maybe an on the others comments, but not on their sanity, or on the science. Get a PhD in Physics and Math and spend a couple more years actually working in Electromagnetics before you comment on the science. Become a successful con man AND get a PhD in psychology and then you can express opinions on the sanity of others.
Now go back to the lego sets and stay off my lawn!
As for the science:
Since the cavity experiments have never been performed, maybe no one knew about this. Plenty of microwave cavities out there, firmly bolted in place,
and no force measurement devices on them, so it was never noticed... Scalability may be a problem for actual use in space or on earth.
eggs-fucking-zachary
"Stratigraphically the origin of agriculture and thermonuclear destruction will appear essentially simultaneous" -- Lee
But they are hurting real science. Look at this fucking EmDrive nonsense for example. It is complete crap, but is a distraction.
In all likelihood you are correct about that. Extraordinary claims needing extraordinary proof and all that. It sounds like another cold fusion fiasco to me. But part of science is testing even the seemingly absurd claims. Once in a while something seemingly ridiculous actually works and we learn something new. That doesn't mean we should believe unsubstantiated claims but science does require one's mind to be both open and skeptical at the same time.
Optimism is one thing, but you need to be real: humans will never travel to another star. NEVER. It is too far. Space is big, and time is even bigger.
And your evidence for this is what exactly? Yes even the closest star is absurdly far away. The nearest star is about 25.3 trillion miles away (4.3 light years). The technology it would require to get even a probe there much less a human is manifestly beyond our current capabilities. But it doesn't follow that because something is difficult that it is also impossible. I seriously doubt we will even get a human to Mars during my lifetime. But I don't think it is impossible - just very hard. I doubt we will travel to another star system within the next 1000 years. But is it possible? I have no evidence that it cannot be done and neither do you.
You claim to care about science but your aren't using the scientific method. If you want to claim scientifically that we cannot ever get to Promixa Centauri you need to have actual evidence to back that assertion up. Show us how we cannot get enough energy or how there are irreducible problems with keeping humans alive during such a journey or some other problem we have no way to get around. Saying "space is big and time is even bigger" proves nothing about the question.
Although it's amazing that you can produce thrust without a mass output it doesn't seem to be very efficient at doing it considering the amount of energy expended vs the thrust generated. Laser pushed spaceships have been theoretically possible but the megawatt lasers and precision focusing required have made the technology largely impractical. It does however warrant more research to see if the technology can be improved and understood. (If it's actually a real effect.) Otherwise other than being a scientific oddity, it's not very useful.
Hopefully the peers that review it will spell better than the /. editors.
https://www.google.com/#q=revi...
errr....umm...*whooosh* *whoosh* Is this thing on ?
I spend my day editing peer-reviewed journal articles. People really need to understand what peer review means, and what it doesn't.
All peer review means is that someone in the respective field looked over the manuscript and didn't see anything *glaring* stand out that would disqualify it from publication. For example, if someone put "E=mc" for special relativity, peer review would catch that mistake and fix it, disqualify the paper, or send it back to the author to fix. However, it does NOT mean that the article is fact-checked or verified for accuracy or scientific rigor.
Peer review is far less important than *replication*, which is what EMDrive requires.
If it's so wimpy, why not use ion drives? I thought it was roughly 100x more efficient than ion drives (in tests), and that's why space-travel enthusiasts were excited about it. Your statement seems to say otherwise.
A key difference between EM and ion drives is that ion drives spew radiation to produce thrust while the EM drive allegedly doesn't. While that may be interesting from a physics perspective, it's not a practical issue from a space travel perspective because spewing radiation (ions) is not a significant problem.
In other words, it's not the apparent "something from nothing" aspect that excites travel enthusiasts, but the allegedly efficiency, because moving fast in space requires a hell of a lot of energy.
EMD titillates (or teases) physicists because of the perpetual-motion-machine-like qualities, but it titillates wannabe space-travelers because it's allegedly far more efficient than anything we have, meaning we could approach the speed of light without mountain-sized fuel tanks/reactors.
Table-ized A.I.
Hold on, wasn't the EM Drive debunked some months back?
https://www.reddit.com/r/EmDri...
If the pseudo random noise is influenced by the state of the EmDrive then it would be very difficult to filter out.
Knowledge = Power
P= W/t
t=Money
Money = Work/Knowledge so the less you know the more you make
>Except that we already have engines which are *more* efficient: photonic drives
Not hardly. If that were the case nobody would care aside from physicists searching for new physics.
Wikipedia says the maximum thrust for a perfectly collimated nuclear photon drive is 300MW/N
https://en.wikipedia.org/wiki/...
and that NASA did done laser-thruster experiments last year reaching 500kW/3.5mN = 142MW/N
- over twice as efficient, I assume because it was a (possibly recycling) "light-sail" design with an external laser, and thus gains twice the momentum per photon (more if they're recycled)
https://en.wikipedia.org/wiki/...
Meanwhile according to the article, the EagleWorks EmDrive experiment claims 1kW/1.2mN = 0.8MW/N
Or almost 400x more efficient than a perfectly collimated photon drive.
And the inventor claims to have improved the ratio by orders of magnitude beyond what's generated by the crude prototype EagleWorks is testing.
--- Most topics have many sides worth arguing, allow me to take one opposite you.
There is no such thing as a proven scientific law. Proofs are for mathematics - i.e. conceptual worlds entirely bound by laws of our own creation.
Scientific laws are simply iteratively improved models of an unknown reality that have thus far failed to be disproven despite many qualified people attempting to do so until the consensus emerges that they are valid. And often they're not even that - Newton's Laws have been disproven yet are still honored as laws because they are easy to work with and, for most things within the realm of human experience, they hold true to the limits of our ability to measure, despite the fact that we now know they are only a special case of a far more complicated relativistic model.
Furthermore we know with certainty that our current laws are flawed - for example both General Relativity and Quantum Mechanics cannot be true as they require conflicting values for the vacuum energy constant, implying that one or both models are flawed. And I could give you a list of well-documented phenomena that are unexplained by currently accepted scientific law, implying that either the existing laws are flawed, or their are further laws that we have not yet discovered.
--- Most topics have many sides worth arguing, allow me to take one opposite you.
Sometimes laws are made to be broken...
A reactionless drive, and the likelihood of it existing, can be compared to a perpetuum mobile. And there is a reason why patents are not granted for perpetuum mobile: it's because they don't work, and can't work.
The further discussion in this, thus, is whether one indeed 'need' to test it, seen the fact there is a limited budget, time and money, of scientific research. And if one deems it is, then why should you then also not claim the same for any perpetuum mobile or other crack-pot idea that pops up, to be researched?
It then is often argued 'because three tests have confirmed it', but that is exactly the crux of the matter: they didn't. There is as much proof or evidence or confirmation for that microwave-oven to be a reactionless device, then there is for any perpetuum mobile to be truly working, or for the 'thrust' to be due to dragon-magic.
My suggestion is: that those who are so convinced of it actually working start a kickstarter, and pay for it that way. Then, everyone is happy: the EM-believers, the sceptics, and the taxpayers.
Most physicists worth their salt realise how EXTREMELY (and I'm using an euphemism here) unlikely this is, and that's exactly why the scientific community at large doesn't jump on it: they have better things to do than waste their time and money on such a thing.
The inventor claims it can be explained by conventional (Newtonian) physics. That is utterly impossible. Newtonian laws (nor GR, *nor* classical QM for that matter) allow for such a thing.
At least White realised this, which is why he invented the "pushing against the virtual plasma" as an 'explanation'. Only problem is, there is no such virtual plasma, at least not in any known theoretical framework (or even an unknown but consistent one), and I didn't see White put one forward neither. So, basically, it has the same validity as saying 'it's pushing against dragon-magic'. It explains *nothing* at all, and thus can't be considered a valid explanation for the force measured neither.
Basically, for all intents and purposes, it IS a reaction-less drive, because it adheres to all the hallmarks of one. Claiming it is not doesn't change that fact. It would be akin to someone claiming the apple he throws and comes down is not due to gravity, but due to dragon-magic. Now, one might *CLAIM* it' not due to gravity, but it doesn't change the fact it IS still due to gravity. And until one comes up with proof or at least a consistent theory which is better than the explanation of gravity (aka, a falsifiable explanation of dragon-magic) such claims change nothing and are nonsensical statements.
To the defence of Tajmar, White, and maybe even the inventor: I don't think it are *deliberate* falsehoods. Contrary to say, Rossi with his scam of the E-cats. I don't think they are scamming or consciously deluding people. I've seen the presentation of White, and noted the critical stance of Tajmar: they don't seem to be deliberately confusing people into believing this story. Certainly not the latter. White might have been a bit too speculative, and the scoop-searching press and EM-fanfappers do the rest.
That said, one can rationally argue, or at least ask the question: with a limited budget for scientific research, if it's warranted to put taxpayers' money in such an extremely unlikely claim - without any theory nor decent experimental data to back it up. Even if it's only 500K, it could be better spend on some other scientific projects.
Or, alternatively, the fanfappers could make a kickstarter for it. I've asked this 6 times already, but: where *is* that kickstarter? What's keeping them from doing one? If everyone of the EM-believers would put their money where their mouth is, it would already have gotten 500K. Everyone happy.
I love new things. Only, I don't *believe* every new thing that comes along, until proof of it has been delivered.
And, as usual, you are reversing the burden of proof. And you know it. I have told you numerous, numerous times in the past, so you AR
--- "To pee or not to pee, that is the question." ---
According to the theory, thrust will increase by orders of magnitude if a high-Q-factor device is used.
And then, the signal would be quite distinct from the noise.
So why hasn't that been tested already? High-Q-factor devices have been manufactured for other purposes.
That that is is that that that that is not is not.
If it works, perhaps they can then find out what we are missing in physics theory. We are obviously missing something, since we can't adequately explains dark energy / dark mass.
If it does, then if they can develop a working theory perhaps it can be optimized for greater thrust. In the vacuum of space I don't think you need a lot to push something.
Perhaps the most common way to measure the efficiency of a traditional rocket is specific impulse: total impulse (or change in momentum) delivered per unit of propellant consumed. Note that this is not a measure of energy efficiency; it's a measure of how efficiently propellant is used. (It's possible to waste a lot of energy in the process of getting your propellant up to extremely high exhaust velocities.)
By that measure, sure, a propellantless thruster's use of propellant is infinitely efficient. But that's not a good way to measure the efficiency of a propellantless thruster.
People who follow the Em Drive usually use a metric of thrust per kilowatt of electric power. Much better; and by this measure, efficiency is definitely not infinite.
That that is is that that that that is not is not.
If it's a reactionless thruster, it's can be made into a perpetual motion machine of the first type. If you design it right, you can get more energy out than you put in. That's infinite efficiency. Or better than infinite efficiency.
Any thruster that violates conservation of momentum also violates conservation of energy.
People who follow the Em Drive usually use a metric of thrust per kilowatt of electric power. Much better; and by this measure, efficiency is definitely not infinite.
People who follow the Em Drive don't typically understand conservation of momentum or conservation of energy. Don't bother using it to fly a rocket, use it to run a generator. Run the generator fast enough, and your one kilowatt of input power will product two kilowatts of output power. Use the first to keep it running, and you get one kilowatt is free power: efficiency, infinite.
http://www.geoffreylandis.com