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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.
Who are "Lawrence, Vera, Sylvester, Brady and Bailey"? Their cats?
Reviw is sooooo important....
-- Make America hate again!
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.
That's all? I'm fully prepared for the Armored Space Nutter division to come out in full force waving their Star Trek box sets and preparing their trip to Andromeda.
Never give up! Never surrender!
That's all? I'm fully prepared for the Armored Space Nutter division to come out in full force waving their Star Trek box sets and preparing their trip to Andromeda.
In the meantime, you're filling in nicely for them.
The shepherds did so well protecting the flock that the sheep no longer believed that wolves existed.
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
The efficiency is very low. Read TFA: "[...] the system is consistently performing with a thrust to power ratio of 1.2 +/- 0.1 mN/Kw ()".
According to TFA, however, they are working on a far more efficient design.
This is your sig. There are thousands more, but this one is yours.
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.
I do not want your cheap brainburning drugs. They are useless for work. And I am a working man today.
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.
The trouble is that the thrust is so low that measuring it reliably is so hard that nobody knows if there is thrust at all or just measurement problems. It's said to be about 1mN/kW, much lower than even an ion drive.
I think there is just noise and no signal and people are seeing a rabbit in the clouds because they're looking for it very hard.
Well within experimental noise - and certainly nothing you're going to propel anything anywhere with.
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. But if there's new physics, then who can say what the eventual application will be? Our first experiments with radioactive materials made things a little warm and glowy (and poisonous) but then fast forward a few decades and we've got mushroom clouds and nuclear reactors.
We don't have a state-run media we have a media-run state.
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.
Its massively inefficient. Its probably the least efficient use of electricity ever invented actually. It works without a fuel tank though. People are only really excited about its potential for space travel because of that. See, if it works entirely on solid-state electronics, without needing fuel reserves, then in theory you can power this from outer space forever just on solar radiation. Up until now, all other rocket technology was limited in range by the physical weight of its own fuel.
I think people don't really get the difference in scale between 1mn and 1kw, so why having the two together makes things so hard.
1mn is of course the weight exerted by 0.1g. That's about half a grain of rice. To get that, you require 1kw. Think about the things that take pr process 1kw of power, e.g. an electric bar fire, a very high end PC, a mid-size UPS and so on and so forth.
They're all large, heavy things, which require considerable cooling to dump that much heat.
So the question is how do you transport 1kW from one place to another. The awnser is of course, wires. Consider the size of the wires, interaction with the earth's magnetic field, thermal expansion of the equipment and so on.
And you've got to figure out the half grain of rice's worth of force from all that.
SJW n. One who posts facts.
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
"It is a good rule not to put overmuch confidence in a theory until it has been confirmed by observation. I hope I shall not shock the experimental physicists too much if I add that it is also a good rule not to put overmuch confidence in the observational results that are put forward until they have been confirmed by theory."
- Sir Arthur Eddington
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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.
You can never take Sir Newton out of the equation.
Well that's the question, isn't it?
We don't have a state-run media we have a media-run state.
There is no similarity. Space nutters are usually tech people who are uneducated in the hard sciences that believe that you can just "scrape dust off of an asteroid" and "turn it into fuel" and "attach scramjets" to a planet (actual quotes from space nutters on Slashdot). And if they believe hard enough, a dream big enough, that everything will happen - because after all: technological progress is inevitable. It will never end!
100% correct. But you will notice they alway shove "NASA" in there anyway. It has all the hallmarks of a hoax.
I'm interested in space exploration as well. There is a difference between an enthusiast and a space nutter. And no: Science Fiction is fiction. "Dream big" only works if you also "work hard" and are realistic about what is possible given the KNOWN LAWS of Physics. Just because you read Ringworld doesn't mean one can be built.
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.
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.
If they verify an observable thrust, then it is a Big Deal because that IS New Physics.
When Fascism comes to America, it will call itself Anti-Fascism, and tell you to give up your guns.
First, "Sir Newton" is incorrect. If you're going to use "Sir", you have to go with "Isaac". "Newton" is correct, as is "Sir Isaac Newton".
Second, Einstein is more correct than Newton. Relativistic physics is pretty much the same as Newtonian for most practical purposes, but diverges under conditions Sir Isaac had no way to consider or test. We've tested relativity to death, and it's always at least as accurate, and in more extreme conditions much more accurate, than Newtonian physics. Meanwhile, we know that relativity is incomplete (we don't know how general relativity works on the quantum scale, for example), and presumably we'll eventually have even more accurate physics. It's conceivable that we'll get the laws of physics just right sometime, but it isn't happening right now.
"When you have eliminated the unacceptable, whatever is left, however improbable, must be the truthiness" - Holmes
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.
The reports are that it's far more efficient than a straight EM drive. Photons make really inefficient reaction mass, since the amount of momentum change you get per unit energy is very, very low. Assuming that the reported thrust is accurate, it means that the drive is reacting against some external matter.
"When you have eliminated the unacceptable, whatever is left, however improbable, must be the truthiness" - Holmes
It's also possible that there are no new physics here, just an example of a misunderstood corner case of existing physics...
Build it, test it, see what happens. Until it's proven (and I mean really proven, not just dismissed) false, it would seem to be worth the research investment.
"Dream big" only works if you also "work hard" and are realistic about what is possible given the KNOWN LAWS of Physics.
Dreaming bit within the known laws stops progress dead in it's tracks. The laws of physics were derived from experimentation, observation and creation. People were getting shocks from electricity over 3000 years before Cavendish electrocuted himself for science and 40 years before current was properly described as a physical property. None of this gets explained by known laws.
While on the topic of electricity Benjamin Franklin published notes on the paradox that was the Leyden jar, something which was built but not explainable by physics. Here we are a few hundred years later and I'm communicating to you by typing on a keyboard sending 1s and 0s to you stored somewhere else on the planet only for text to come up on your screen.
You think too small. Known laws of physics get in the way of bigger thinking such as sending power wirelessly (thought impossible, along with everything else we take for granted now).
Why not? If this technology works, it changes the game in space travel. It seems there is a large requirement (today) for thrust vs energy, but with experimentation, theory, and improvements in understanding this may become viable for flying car type energy/thrust requirements. It really surprises me whenever I read a story about the EmDrive. It makes hypocrites of all the "scientists" and our general application of science, in general.
Skeptics claim:
"It violates Newton's law"
It is a bunch of tomfoolery
Its a measuring error
Horseshit. Any real scientist knows: Nullis in verba, or question everything. We thought the world was flat, we thought the world was at the center, then the sun, now... there is no center. We experiment, we learn, we work out what we think is right is right, or what we thought was right is wrong. The universe is mysterious, and full of wonder. Offer no ridicule until you have proven someone wrong, conclusively! Otherwise, your no better than a religious zealot. Science itself deserve better.
If it manages to violate conservation of momentum and that stands up to the inevitable scientific pig pile that follows, I'll be impressed.
One theory of how it works...
http://www.emdrive.com/theoryp...
I am not a physicist, and don't *really* understand what they are theorizing, except that they are suggesting that special relativity applies to the engine instead of newtonian mechnics. (which isn't really a surprise).
If you can follow the math and the judge the theory, have at it...
I think it's a prevailing attitude on Slashdot -- look at the comments of any article that has a positive outlook on future technology. But it's not just slashdot, it's true in most educated circles too -- general skepticism and cynicism. Most people's BS filters are turned to 100% -- which keeps them safe against the crazies, but saps the imagination. Even at work, doing natural language processing research, I find it a little depressing that the common view among my colleagues is essentially "human level intelligence will never happen".
You find it depressing because you can't handle reality. That is sad. No one has time to chase down every crackpot who comes up with a "magic machine". We have plenty of those. You cannot produce a machine that violates known laws and expect people to take it seriously.
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
Unless that machine's characteristics are reproducible, and there's no attempt at obfuscating the experiment to keep others from attempting to reproduce the results... You know, like publishing a peer-reviewed article and such.
Most of the time, the known laws of physics are adhered to because, most of the time, people are exploring avenues where they can achieve a desirable, expected result. Sometimes, though, those laws are broken. That's called a discovery, and it means that, actually, those known laws are an approximation, not laws at all.
We will never be the change to the weather and the sea
Well, we don't have the technology to accelerate the ions to anywhere near the speed of light in a rocket engine. The Dawn spacecraft for example was 35% Xenon by mass.
SJW n. One who posts facts.
Nonsense. Name one of the basic natural laws that has been 'broken'.
And no, Newtons' theory of gravity wasn't broken by that of Einstein: http://soi.blogspot.be/2013/05...
I'm saying this in front, because it the typical thing people who are not to knowledgeable about the topic come up with. No, it's not been 'broken'. It is *incorporated* into GR as a special case, but within its domain and a given framework, it remains valid.
--- "To pee or not to pee, that is the question." ---
Of course there is bullshit out there. The so called "perpetual motion machines" and "1MW generators in a shipping container", etc.. etc.. are all bullshit.
But, don't throw out the baby with the bathwater. Here is a machine, that exhibits a thrust in a closed system with no fuel or mass leaving the closed system. The engineers wrote a paper on how to build another unit. Other units were built, and the measurements done by independent observations confirm the measurements of the first team.
These observations conflict with *understood* laws of physics and nature. There is obviously one of two things happening:
1. We have an experimentation error. OK. No problem. The more teams we have working on it, the more likely we will find the flaws in the method if this is the case.
2. We have an issue with the law of physics that are being contradicted. Let is revise the law and move the question back to the theorists to write a better law.
If we have in fact discovered a violation of one of the laws, then thats a really really big deal. It will change the game in terms of transportation technologies with regards to space travel. It would vastly change the useful life of satellites that require fuel to maintain orbits. It would open up vast amounts of resources to research and develop our ability to apply the new principle. It would be as big a deal as when we learned how to use sails to move against the wind.
But to just write it off as horseshit just because we don't like how it violates what we think we understand? No. A question has been asked. Science must answer. And if we have found a new principle, to quote John Hammond:
"How can we stand in the light of discovery, and not act?"
Sure, here you go, since you couldn't be bothered to check the link:
We will demonstrate that the Einstein Field Equations reduce to Newton's Law of Gravity in the case of a weak field and slow-motion of a particle (v less than the speed of light, c).
As we have already seen, Newton's Gravitation Law can be written as
(1) 2 = 4G, Equation (16) in Newton's Law of Gravity.
In free-fall, a particle satisfies,
(2) d2x/dt2 = F/m= –, Equations (4),(15) in Newton's Law of Gravity.
In tensor notation, this is written as,
(3) ,ii 4G
(4) d2x/dt2 –,i
Corresponding to (1) in General Relativity is the Einstein Field Equations, which can be written in the trace-reverse form,
(5) R = (8G/c4)[T – ½Tg]
And corresponding to (2), is the geodesic equation,
(6) d2x/d2 = –(dx/d)(dx/d)
Our task is to show that (5) will reduce to (1) in low gravity, low velocity.
The first approximation we make is that the particle is moving at velocity near zero,
(7)(dx/d) (dt/d,0,0,0)
The only non-zero term for the 's in (6) will be =i, = =0. The equation becomes,
(8) d2x/d2 = –i00(dx0/d)(dx0/d)
Or
(9) d2x/d2 = –i00(dt/d)(dt/d), (x0 =t)
But by the chain rule of calculus,
(10) d2x/d2 = (dt/d)(dt/d)d2x/dt2
Therefore,
(11) d2x/dt2 = –i00
Equation (4) and (11) yields,
(12) ,i = i00
Using the Christoffel symbols of the second kind ( Torsion =0 in GR),
(13) = ½ g(g, + g, – g,)
Again setting =i, = =0, equation (12) becomes,
(14) ,i = ½ gi(g0,0 + g0,0 – g00,)
Since the time derivative of the metric is zero (Einstein Equivalence Principle), the only surviving term is = i. Then,
(15) ,i = ½ gii(– g00,i)= (–½g00,i)
A solution is,
(16) g00 = – c2 – 2
Turning to the Einstein Field Equations (5), and from (16), we only need the time-time equation, = = 0
(17) R00 = (8G/c4)[T00 – ½Tg00]
But
(18) T00 = c4 and T = g00T00 = (–1/c2)c4= –c2
Substituting (18) into (17), we get,
(19) R00 = 4G
Now to get to Newton's Law, equation (1), we need to work on the left-hand side of equation (19).
For that we use the definition of the Ricci tensor,
(20) R = /x – /x + –
From (19), = = 0,
(21) R00 = 00/x – 0/x0 + 00 – 00
In low gravity, the square of the 's is zero, and its time derivative is also zero. The only surviving term is,
(22) R00 = i00/xi i00,i
But from (12), repeating below,
(23) i00 = ,i
Take the derivative, and then use (23)
(24) i00,i = ,ii = R00
Using (19),
(25) ,ii 2 = 4G
And that is Newton's Law of Gravity (1).
--- "To pee or not to pee, that is the question." ---
We don't want to just have a neat little gimmick, we want to know how it works and what else we can do with the concept. Knowing whether it is pushing on a magnetic field or not is a step towards that.
"When you have eliminated the unacceptable, whatever is left, however improbable, must be the truthiness" - Holmes
You can't just claim to have a machine that violates known laws and expect to be taken seriously, but if you actually *produce* such a machine and it really does violate known laws, I would most certainly hope that everyone pays attention. Regardless of whether or not that's the case here, if someone makes a conclusive and reproducible observation that violates our knowledge of the laws of physics, then our knowledge needs to be reexamined. To act otherwise would be like saying that Michelson and Morley should have tossed out their interferometer because the results it produced violated the laws of physics known at the time.
As far as the EM drive is concerned we're still waiting on the "conclusive" bit, but we seem to be getting closer and closer.