Leaked NASA Paper Suggests The 'Impossible' EM Drive Really Does Work (sciencealert.com) 711
A source close to NASA Eagleworks has leaked the test results of the 'impossible' EM Drive. While it's important to note that the results that have been leaked haven't been published in an academic journal, they do suggest that the system works and is capable of generating force of 1.2 millinewtons per kilowatt in a vacuum. ScienceAlert reports: The paper concludes that, after error measurements have been accounted for, the EM Drive generates force of 1.2 millinewtons per kilowatt in a vacuum. That's not an insignificant amount -- to put it into perspective, the super-powerful Hall thruster generates force of 60 millinewtons per kilowatt, an order of magnitude more than the EM Drive. But the Hall thruster uses fuel and requires a spacecraft to carry heavy propellants, and that extra weight could offset the higher thrust, the NASA Eagleworks team conclude in the paper. Light sails on the other hand, which are currently the most popular form of zero-propellant propulsion, use beams of sunlight to propel them forward rather than fuel. And they only generate force up to 6.67 micronewtons per kilowatt - two orders of magnitude less than NASA's EM Drive, says the paper. The NASA Eagleworks team measured the EM Drive's force using a low thrust pendulum at the Johnson Space Centre, and the tests were performed at 40, 60, and 80 watts. They were looking for any sign that the thrust could be a result of another anomaly in the system, but for now, that doesn't appear to be the case. "The test campaign included a null thrust test effort to identify any mundane sources of impulsive thrust, however none were identified," the team, led by Harold White, concluded in the paper. "Thrust data from forward, reverse, and null suggests that the system is consistently performing with a thrust to power ratio of 1.2 +/- 0.1 millinewtons per kilowatt." But the team does acknowledge that more research is needed to eliminate the possibility that thermal expansion could be somehow skewing the results. They also make it clear that this testing wasn't designed to optimize the thrust of the EM Drive, but simply to test whether it worked, so further tweaking could make the propulsion system more efficient and powerful.
This is interesting (Score:5, Funny)
Because if Trump wins, we need a way to leave this planet...
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To use this drive, you have to have already left the planet (be in orbit)
I think gravity (at the suface) is about 10 Newtons per Kg
so you'd need 8.5 MW per Kg of spacecraft
So 17 Gigawatts forsomething the size of a shuttle
We'd need a fusion reactor to power it
Re:This is interesting (Score:5, Funny)
I thought we invented a fusion reactor that would go on the back of your car? Back in 2015, or before.
Re: This is interesting (Score:5, Insightful)
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Re:This is interesting (Score:5, Funny)
I'm assuming you didn't get very good grades in spelling, grammar, that sort of thing...
That said, if you're ignoring units and just assuming, you don't deserve very good grades in a physics exam. Math exam, maybe....
Re:This is interesting (Score:5, Insightful)
Not quite. A bit of cart-before-horse.
Once there's enough testing done to prove it has potential, then engineers will take it, play with it, improve it, apply it, then sometime later, physicists and other scientists will figure out precisely why it works and why what the engineers did worked.
Strat
Re:This is interesting (Score:5, Interesting)
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Re:This is interesting (Score:5, Interesting)
If you have enough delta v you can fly on a hyperbolic orbit, which can be as fast as you like. That dv can be delivered all at once, at the beginning (and hopefully the end) like we do it now, or it can be delivered continuously, like we'd do with this engine.
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What it'd really be useful for is an interstellar probe. Propellant-less acceleration can get you near the speed of light in a few years.
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You are a perfect example of the anti-intellectualism that is destroying the UK. Literally destroying it, as Scotland and maybe Gibraltar look likely to leave the union in some fashion.
I hope you enjoyed seeing men-of-the-people like Boris Johnson and Michael Gove, both of whom went to Eton and are millionaires, win that referendum. Especially now our future looks bleak, the Pound has crashed and continues to fall, and bigots have been emboldened by what they perceive as support.
Of course, in reality only a
Re:This is interesting (Score:4, Informative)
According to https://en.wikipedia.org/wiki/... [wikipedia.org] the UK (etc) turnout was 72.2%, of which 51.9% voted to leave and 48.1% (including me) voted to remain. Put another way, of the eligible voters about 37.5% voted to leave, 34.7% voted to remain, and 27.8% did not vote.
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It's about 28% of the adult population. About 1/4 are not registered to vote. Of the ones who are, 72% voted, and of those just over half voted to leave. The number of adults who are not eligible to vote (mental health, prison etc.) is negligible.
My bad, I typoed it, I meant 28%, not 18. Also, keep in mind that the question was "do you wish to remain in the EU, or leave the EU", it didn't say anything about immigration controls, leaving the common market, repealing EU laws or any of the other issues that ne
Re:This is interesting (Score:5, Funny)
Kudo's to you. You're the hero we really need, if somebody tells you "Don't touch the stove it's hot and will burn you" you slap your hand on their and hold it there till it's a piece of crispy bacon. Thanks Anonymous Hero guy.
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I'm curious though, why a lefty wanted to do so?
"Leaving the EU would undoubtedly weaken the ability of British, European and even US imperialists to dominate the globe, thus taking our struggle for socialism one small step forward"
Official CPGB position [cpgb-ml.org]
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In short: people who think the status quo is a horrible disgrace will vote for anything that'll tear it down. That's also why some liberals are voting for Trump, they hate the system and want it to go down in flames. How one can hate the status quo that much while living in one of the world's wealthiest countries, I'm not sure (speaking as an American below the poverty line who would much rather change the system gradually than have a revolution).
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A Commons vote will pass. The SNP would vote against and Sinn Fein might turn up at Westminster for the first time ever to vote against but that's only about 55 votes, a tad short of the 325 a full turnout requires. Someone did an analysis immediately after the referendum on how MPs would be required to vote to reflect their constituents choice in the event that Parliament had to ratify the referendum. Some approximation was required since the referendum count was not by Westminster constituency, but their
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"I am planning to get out while I can whichever candidate wins. They are all mentally ill, more than a few sociopathic,..."
Sure, but one of them is also yuugely stupid.
I blame 2016 (Score:5, Funny)
The physical laws went out the door months ago.
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Re:I blame 2016 (Score:4, Insightful)
This is literally what it is, specifically it's acceleration that is being rounded up.
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The computer in which our entire Universe is simulated was designed by their version of Intel and has a floating point error.
Re:I blame 2016 (Score:4, Insightful)
Well, laws of physics are created by humans to understand and explain how things work, they are far from absolute (yes some scientists really believe they are absolute, dumbass scientists that is).
The laws of physics are absolute even if we don't know exactly what they are yet. If they're not then you're essentially saying that anything can happen at any time for any reason, i.e. magic exists.
There are still so many mysteries that cannot be exlpained using the 'laws of physics' as they are now, so even in that regard you know these 'laws' are not definite..
That's just flat-out mysticism.
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Well, then explain how this EM drive works! ;-)
It doesn't. All the effects seen so far are experimental error.
I need to see more (Score:2, Insightful)
I need to see more than this article to convince me this works.
Re:I need to see more (Score:5, Interesting)
Here's a link to the NASA paper on the apparently successful test: https://drive.google.com/file/... [google.com]
And here is a presentation by the technology's inventor, Roger Shawyer https://vimeo.com/channels/Emd... [vimeo.com]
Warning: Shawyer may well be brilliant, but he is the Anti-Musk in terms of his presenting and motivational skills. This guy could seriously announce a working warp drive in a way that would make people walk out of the presentation half way through. If he has funding problems, he needs to get someone else to present his technology and business case for him.
Re:I need to see more (Score:4, Interesting)
Warning: Shawyer may well be brilliant,
Nope. He first "derived" it using relativity and then ran with the result. It was obvious to just about every physicist ever that the result MUST have been bogus because relativity probably conserves momentum. The thing is, that's a mathematical proof so it holds always, no matter how clever your shape, how many springs or magnets you have or how smart you seem to be.
It is literally impossible to have a reactionless thruster while constrained by the bounds of relativity. This is well known and thoroughly proven and is basic undergrad level physics, yet was apparently unknown to Shawyer.
Not only that, he wouldn't even accept the result (i.e. Noether's theorem) until someone found the actual error in his working. It wa eventually found.
Not a great start for brilliance.
Re:I need to see more (Score:5, Informative)
Well, if the drive works, then either the symmetry underlying conservation of momentum isn't entriely true (it wouldn't be the first time we discovered a surprising lack of symmetry, you know), or the drive isn't entirely reactionless. I think it is important to always be willing to keep an open mind, when we don't know for certain; what you are saying is "No, impossible, so I am not even going to look". Personally, I think preservation of momentum is true; so in my view there must be an escape of momentum that we haven't figured - if this works. This doesn't strike me as unthinkable - after all, energy is put in, so it must go somewhere. We just need to find an explanation.
Re:I need to see more (Score:4, Insightful)
Well, if the drive works, then either the symmetry underlying conservation of momentum isn't entriely true (it wouldn't be the first time we discovered a surprising lack of symmetry, you know), or the drive isn't entirely reactionless.
Yes, and that would mean it's a perpetual motion machine too. This would be pretty much the largest result in physics ever. You can see why people, including myself reckon it's completely bogus.
or the drive isn't entirely reactionless
Then it has to be generating reaction momentum from something. The thrust is too high for that.
I think it is important to always be willing to keep an open mind, when we don't know for certain; what you are saying is "No, impossible, so I am not even going to look".
No. You need to be open minded, but not so open minded that your brain falls out. What makes *this* perpetual motion machine different enough from all the others that it's worth a look? People can come up with bogus ideas faster than you can find flaws in them if you're barred from using tests like "does it conserve energy and/or momentum".
so in my view there must be an escape of momentum that we haven't figured
But we already understand the mechanisms for such things. You can synthesize mass from energy and then accelerate it, or just generate photons (which have momentum) and dump them out the back. But we know what the theoretical maximum efficiency for those is too. And the thrust here is too high. And if the thrust is too high, then it's a perpetual motion machine.
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What makes *this* perpetual motion machine different enough from all the others that it's worth a look?
Well, the lack of someone trying to sell something while hiding how it works. That and there have been several independent groups that have already looked and haven't found something obviously wrong. So the chances of this being a real effect have gone from one in millions to one in hundreds. The smart money is still on "there's something that's been overlooked". (Faster than light neutrinos = dodgy cable???) But at least this is now interesting.
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>What makes *this* perpetual motion machine different enough from all the others that it's worth a look?
The fact that we've had endless tests all apparently showing it working ? Don't get me wrong, I'm sceptical myself - it's entirely possible this will prove to be a measurement error in some subtle area we've never known to look for one - but if that is, that in itself would lead to new discoveries.
Figuring out WHY this appears to produce thrust is basically guaranteed to lead to an advancement of physi
Re:I need to see more (Score:4, Insightful)
And yet, it does seem to work.
The main takeaway here is that if it really does works we have no idea on how. Zero. Nil. Nada. Worrying about conservation of momentum/energy when when don't really know what physical process is at play here does not make sense - for all we know we live in the aether and the device materializes invisible paddles to row it.
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And yet, it does seem to work.
The keyword here is "seem". In physics, not everything is as it seems. Figuring out why we have something that seems to violate existing theories is what's fascinating. It could lead to an expansion of existing theories, or it could turn out that we simply overlooked something already known. But let's not jump from "seem to" to "do".
Re:I need to see more (Score:4, Interesting)
"for all we know we live in the aether and the device materializes invisible paddles to row it."
We do live in the aether. The qualitative description of modern quantum field theory is pretty much indistinguishable from qualitative descriptions of some aether theories. Relativity suggests that you can't paddle through the aether, but one of the theories for how this thing works is essentially that.
Read up on this guy - Physics from the Edge (Score:3)
A better and far more plausible explanation for what's happening is here. [blogspot.com]
And this fellow doesn't just do some hand waving. He has a theory, it is coherent, it is testable and falsifiable, and it also explains the galaxy rotation problem and the flyby anomaly accurately. As well as the EmDrive.
He's worth reading.
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The trouble with questioning our current understanding of physics is that its so damned accurate. QED in particular has been tested to obscene levels of accuracy.
So if its truly new physics at work, it means that its either a) a smaller effect than we can currently measure (in which case, how does it generate so much force?) Or b) something within our current realm of experiments that somehow everybody since Newton or even before has managed to just overlook continuously.
Or of course there's option c) hum
Re:I need to see more (Score:5, Informative)
The problem with the paper is twofold:
1) After one year, it is still not published in a peer reviewed journal. This happens on occasion. However:
2) The data is about as flakey as it gets. Eg. the forces measured for the 60W power level range from 40 micronewton to 120 micronewton. This goes completely unexplained and all they do in the paper is some statistics voodoo to get some nice looking numbers out of this mess.
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You should give an explanation when you do an experiment six times under the same conditions (60W power) and you get the following results (in micro newtons): 42, 67, 83, 92, 105, 128
Leaving this unexplained is a very good argument against it.
I thought... (Score:2)
I thought the science was settled on Newton's laws...
Re:I thought... (Score:5, Informative)
I thought the science was settled on Newton's laws...
First rule of science: Science doesn't settle
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First rule of science: Science doesn't settle
Unless it's global warming. Then if you don't agree that the science is settled it's
Silence ... I kill you
Re:I thought... (Score:5, Informative)
http://www.americanthinker.com... [americanthinker.com]
http://www.killclimatedeniers.... [killclimatedeniers.com]
http://www.climatedepot.com/20... [climatedepot.com]
Calling upon the government to execute those with a different point of view is something I'd consider a death threat.
So not settled... (Score:3)
No, it really does. Conservation of momentum is a principle very deeply baked into physics and has had a vast amount of testing. It's reached the point where anyone claiming otherwise is quire reasonably considered a crackpot unless they have some quite amazingly compelling evidence.
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I thought the science was settled on Newton's laws...
Is this post from 1905?
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How about you read TFA and then comment?
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You should probably read about science since 1905 before commenting then because there are many situations where newtons laws don't hold up. Relativity is one example. So no, they're hardly settled.
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Is this post from 1905?
No, it's from ignorance.
Casimir effect (Score:5, Informative)
I thought the science was settled on Newton's laws...
Firstly, Newton's laws are based on observation and assumptions.
The observations gives us formulas that seem to fit, but there's no guarantee that those formulas describe all situations in the universe.
The assumptions, from Noether's theorem stating that symmetries imply conservation laws, are that the universe is smooth, in the mathematical sense of smooth being that space is infinitely divisible. We know that last part isn't true: you cannot measure position to an arbitrary precision in the universe.
It is therefore seen that Newton's laws become increasingly inaccurate when the scale is very large (relativity), or very small (quantum mechanics).
You might check out the Casimir effect [wikipedia.org] some time.
It's not predicted by Newton's laws, but measurable and predictable using QM.
Anyone who says "EM drive cannot work because it violates my understanding of physics" should really check out the Casimir effect.
If your understanding of physics does not predict the Casimir effect, you probably shouldn't be commenting on the EM drive, or results from NASA rocket scientists.
Re:Casimir effect (Score:5, Insightful)
This is ridiculous. Conservation of momentum is valid in both quantum field theory and general relativity, there are an appropriate versions of Noether's theorem for them. And I don't see why are you harking about the Casimir effect: it doesn't violate conservation of momentum either.
Your suggestion that conservation of momentum might fail because of some fundamental discretization of space is also insane: first of all this is just speculative physics at this stage. Second, everyone that does speculate about it agrees that to probe the existence of this discretization would require particle collisions with energy around the Planck energy, about 10^28 eV. For comparison, the maximum we can do now, in the LHC, is to collide particles with energy of 10^13 eV.
To think that some lame tabletop experiment using only classical electrodynamics, running at most at 80 watts, somehow magically found a way to probe phenomena from an energy scale 15 orders of magnitude larger than the LHC scale, just shows a complete lack of knowledge of all the science involved. At the very least, it would show that the whole particle physics community are complete idiots for spending billions of euros in the LHC, while even more revolutionary science could by done on spare change by Eagleworks.
LEDs, Axions and Scotch Tape (Score:4, Interesting)
Second, everyone that does speculate about it agrees that to probe the existence of this discretization would require particle collisions with energy around the Planck energy, about 10^28 eV.
That's a rather strong statement considering that there are groups on ATLAS and CMS looking for evidence of Large Extra Dimensions which would reduce the energy scale for this to a few tens of TeV. Personally I don't think they will find anything but certainly they are clearly speculating about it at far lower energy scales.
To think that some lame tabletop experiment using only classical electrodynamics, running at most at 80 watts, somehow magically found a way to probe phenomena from an energy scale 15 orders of magnitude larger than the LHC scale, just shows a complete lack of knowledge of all the science involved.
Unfortunately again this is not really a correct thing to say because there are such experiments [wikipedia.org] hunting for axion models of Dark Matter. The LHC is one way to get at high energy physics that is almost guaranteed to find new physics in our energy reach so it is worth the huge cost. However this does not rule out others trying lower budget approaches which can afford to be riskier and to only probe certain models. It is worth remembering that only a few years ago the Nobel prize was awarded to a group which essentially used scotch tape to separate graphite layers something which far more expensive approaches had failed to do.
Re:LEDs, Axions and Scotch Tape (Score:5, Insightful)
Separating graphite layers does not contradict our basic understanding of physics. I don't have any problem with doing it with scotch tape. Ditto for hunting axions: it is an extension of known theories, not a breakdown of our fundamental theories (that is speculated to happen at high energies). But even hunting axions is already much harder than building this stupid EM drive: they had to make a very specialized very sensitive apparatus, for the simple reason that if axions were easy to detect they would have already been detected.
Large Extra Dimensions, on the other hand, is another story: there is no half-way decent theoretical model that predicts them, they are just pure speculation. And they were predict to show up at the LHC scale, with the prediction now changed to just above LHC scale, since they did not show up. And doing that is free, since there is no model to build, you just need to throw some numbers in the air.
Contrast this with fundamental discretization, which is expected to happen for good theoretical reasons, and there are actually some speculative theories (string theory and loop quantum gravity) that implement it.
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You seem to be arguing against reality here: The EM drive is doing something. Fine, you reject all theories of why it "works". No problem. Regardless, your arguments that it can't work fly in the face of reality because it actually does seem to work.
The real question here is why does it seem to work? Observational error? Exotic physics? No matter how many theories you shoot down, a theory still has to be advanced otherwise, the results can never be explained. That leaves us in a much darker place.
Re: LEDs, Axions and Scotch Tape (Score:4, Insightful)
This paper does not show new physics. It shows a combination of experimental error and wishful thinking.
take THAT, Slartibartfast! (Score:5, Funny)
Re: Casimir effect (Score:3, Insightful)
Logic and math can't prove anything is true in the ultimate sense. All math is built on unprovable assumptions called "axioms". Logic cannot prove truth, only consistency, or contradiction. That's why science has to complement math and logic with actual observations.
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Has this been tested? No. That is an assumption. If the nature of the effect is not understood, then such an assumption may well be wrong, along with your conclusion.
Please if you're going to argue about this then think through the consequences of what you say! If it's power is not constant and so depends on its speed then that means absolute speed is a thing and BAM there goes the rest of relativity.
And there's the thing, people have already tried in the past to measure absolute speed, back when the lumini
Re: I thought... (Score:3)
It's not so much newtons laws per se, but energy and momentum conservation laws which are a consequence of very fundamental symmetry laws. See Noether's theorem. That's why physicists have very hard time buying anything that violates these very fundamental principles.
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t's not so much newtons laws per se, but energy and momentum conservation laws which are a consequence of very fundamental symmetry laws.
1. The EM Can't Call It A Drive In Good Conscience Yet consumes energy.
2. Photons have momentum.
But yeah, it's still very hard to believe.
Re: I thought... (Score:5, Informative)
Yes photons have momentum and a photon drive would be 1kW / 0.00334 millinewtons.
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I'm sure we'll find some explanation that requires only a fairly moderate change in our understanding of what constitutes action and reaction.
It's vastly more likely it's experimental error. We're talking about 10mn/kW or so. Most people just don't understand the difference in scales.
Go bust open your microwave, that's got nearly 1000W of microwave generating capacity in it (probably 700-800W). Now find something weighing a milligram. About half a mosquito should do. Now figure out how to get that much powe
1/3 lightspeed (Score:5, Interesting)
Ran some numbers. Assuming the power generator and thruster itself has zero mass (obviously not, but it lets us set an upper limit), the energy available in 1kg of U235, at 1.2 millinewtons/kw, would accelerate that 1 kg mass to about 0.35 C, over the course of about 1000 days.
Add in mass of ship, generators and thrusters and you're looking at considerably less acceleration and top speed, but if this thing works at all (a big IF, granted), manned starships are just within the range of possibility. It'd still be a multi-year (probably multi-decade) trip, but hey.
Actually, 0.043 c (Score:5, Informative)
I believe your math is wrong. U235 releases 202.5 MeV per atom undergoing fission, so that means 1 kg can generate 83.14 TJ from fission [wikipedia.org]. Assuming 100% efficiency, a massless drive, and no mass loss from propellants, that means there is enough energy from fission to reach a velocity of 0.043 c relative to the rest frame.
dE = (m - m') c^2 = m' c^2 (gamma - 1) => m' c^2 = m c^2 (1 - dE/(m c^2)) = m c^2 (1 - rho)
rho = dE/(m c^2) = 83.14 TJ / 89.88 PJ = 9.25e-4
rho = (1 - rho) (gamma - 1) => gamma = 1/(1 - rho) = 1/sqrt(1 - beta^2)
(1 - rho)^2 = 1 - beta^2 => beta^2 = rho (2 - rho) = 1.85e-3
beta = sqrt(rho (2 - rho)) = 0.0430
Re: 1/3 lightspeed (Score:5, Funny)
Police Officer: "The light was red; you went through an intersection on a stop light"
Starship Officer: "It was green at the speed I was going"
Re: 1/3 lightspeed (Score:4, Informative)
Police Officer: "The light was red; you went through an intersection on a stop light"
Starship Officer: "It was green at the speed I was going"
Did you know that before he wrote the novel The Martian, Andy Weir had a geeky web comic called Casey and Andy? This strip was very popular:
http://www.galactanet.com/comic/view.php?strip=39 [galactanet.com]
Re:1/3 lightspeed (Score:5, Interesting)
I suppose the first thing we'd do if this worked would be to send out a bunch of unmanned probes towards interesting targets, and they would send back information as they cruised by these targets at 1/3 c. Earth is about nine light minutes from the Sun, so 1/3 c means you travel about 1 AU in a half hour. Assuming you start searching for Earth-like planets at a 2 AU out (you'd probably start sooner), the probe would have a couple hours in which to look around for planets, and take telescopic pictures (panning the telescope to compensate for motion during exposure) and other measurements of any planets found. That should be enough to determine whether it's worth sending a probe that would decelerate, or possibly humans. And the initial probe would either go off into empty space, or be re-directed to another star.
For Alpha Centauri, time to periapsis for a non-decelerating probe would be s.t over 12 years (not taking into account how long it takes to accelerate at 1/3 c, and assuming you don't try to accelerate faster than that). Four+ years to get the signal back. So we could know within 20 years whether it's worth exploring any given star system, although for the closest and most interesting targets I'm sure we'd send probes capable of decelerating immediately after the non-decelerating probes, just because we know so little about other stars.
I want to believe.
It's the Flux Capacitor (Score:5, Funny)
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I'm no where near as smart as most of you.. (Score:2)
Can someone clued up here, please explain to me more about the figures of this thing in regards to propulsion?
It's obviously generating very little propulsion, but it's "free" if electricity is free, right?
So if we had a massive reactor shoveling power into it, would it generate more, or the device need to be larger or we need more of them?
Could we build a ship with the existing one, assume again unlimited power reactor somehow and then fire the thing up, would I be right in thinking this thing would incred
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It's usefulness as a propulsion device remains to be seen.
First, it may ultimately be determined to be the result of experimental errors or failure to account for various effects. Good science, but boring outcome.
Or it may be found to work, and be proven to be exploiting some currently unknown or poorly understood area of physics. Understanding then how it works and how it produces its force will lead to potential useful applications. If it's understood how it works its possible one could be designed to hav
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I get the no fuel and I get the very little force but I can't imagine the implications for it.
A slow, steady thrust. In the vacuum of space, there's no thrust wasted to keep you at speed, like flying in the atmosphere. Over time, even a tiny thrust can build you up to phenomenal speeds. Just make sure you turn your engine around and start to slow down at the halfway point of your journey.
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That's why it's so hard to test, YET so enticing at the same time.
There may indeed be a very minor oddity, in terms of effect, in quantum physics that we haven't discovered yet that allows the phenomenon without throwing out all prior knowledge. We just may be applying existing knowledge wrong, assuming a spherical cow somewhere when it's really an octahedron or the like.
I'm at a loss to think of something from technological history that i
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I'm at a loss to think of something from technological history that is comparable to this possibility: something that didn't seen possible or feasible under the known laws of physics or nature, but turned out to actually "fly".
The laser perhaps? I don't think it could be conceived of until Einstein.
https://en.wikipedia.org/wiki/... [wikipedia.org]
The difference with this discovery (if true) is that Einstein laid the theoretical framework and then the laser was built 43 years later (36 years for the maser) while in this cas
Yes, nobody knows, yes, poop in some bamboo (Score:5, Insightful)
I'm no physicist myself, and physicists don't understand this thing anyway, but here's my understanding:
Yes, appears that the only input is electricity, and it seems to produce thrust. So if electricity is free, a tiny amount of thrust is free. I say it APPEARS that the only input is electricity- many reactions which we now understand include oxygen from ambient air as an input, and that might have easily go unnoticed in an experiment before the reaction was understood. Similarly, it's possible that this thruster is using some non-obvious input, such as ambient radiation.
We don't know if one could be built much larger, or what the current capacity is for a given size. Maybe a 100,000 watt one could be small, maybe it would need to be very large. Maybe it would be far more efficient, maybe far less. We're still trying to confirm that the thing works at all.
> would I be right in thinking this thing would incredibly slowly start moving the ship and over a ridiculous amount of time, eventually be moving very rapidly and in theory (?) just keep on accelerating?
Yes, in theory, up to near the speed of light. Or maybe not. 1500 years ago someone discovered that if you burned charcoal mixed with livestock poop in a bamboo shoot, you got a similarly weak thrust. Later we figured out it was the dried pee, not the poop, that mattered and adding sulfur helped. So a thousand years ago they had black powder rockets, which kept accelerating through the air as long as the engine kept burning. Now we know that a rocket won't keep accelerating forever in air, but it took a thousand years to figure that out. We're still in the "poop in a tube" stage of EM drives, so we really don't know what the potential is.
Re:Yes, nobody knows, yes, poop in some bamboo (Score:4, Funny)
Or maybe not. 1500 years ago someone discovered that if you burned charcoal mixed with livestock poop in a bamboo shoot, you got a similarly weak thrust. ... We're still in the "poop in a tube" stage of EM drives, so we really don't know what the potential is.
1,500 years ago people also discovered (repeatedly) how to turn base matals into gold, that draining one of the humours fixed the disease causing that humour and that barnacle geese hatched from barnacles attached to driftwood.
We're not at the poop-in-a-tube stage of the EM drive, we're at the leeches to drain blood stage.
Re: Yes, nobody knows, yes, poop in some bamboo (Score:3)
Btw you know we actually have medical leaches and use them after surgeries like finger reattachment?
Re: (Score:3)
The errors of thought made herein:
1)The 'empirical testing' has showed nothing that isn't FAR more likely to be explained by a measure error than by a breaking of all known physics. The fact that Tajmar found NO force anymore merely by inverting the direction of the device is strongly indicative of that. After all, if it were a reactionless device, the direction (left, right, upwards, downwards,...) would not matter in measuring the force if that force would really be due to the 'resonance of microwaves',
Re: (Score:2)
The practical implication is that if such reactionless drives are possible, the spacecraft will still need to carry a power source to run it, but not the huge masses of fuel to be spewed out the back to provide Newton's "equal but opposite reaction".
This is a technology that you hope for (new physics) but bet against (conservation of momentum). Very telling in the Wikipedia writeup is that one proponent got thrust in all of 7 tests - but 4 were in one direction and 3 in the opposite direction. This strong
Test it in space? (Score:2)
I think the next logical step is to test "fire" an EM drive in the vacuum of space and see if it is still producing thrust when moving around the earth in both zero gravity and zero atmospheres.
A positive (speaking) result in that instance would go a long way to proving whether or not it was capable of driving future space exploration
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I think the next logical step is to test "fire" an EM drive in the vacuum of space and see if it is still producing thrust when moving around the earth in both zero gravity and zero atmospheres.
A positive (speaking) result in that instance would go a long way to proving whether or not it was capable of driving future space exploration
Problem is, that requires a pretty big cash investment just to test an unproven and scientifically dubious technology.
massive irony (Score:3)
Re: NASA Eagleworks is NOT NASA! (Score:4, Informative)
They are directly related. https://ntrs.nasa.gov/search.jsp?R=20110023492
Re: NASA Eagleworks is NOT NASA! (Score:4, Informative)
They are directly related. https://ntrs.nasa.gov/search.j... [nasa.gov]
As the NASA document you cite [nasa.gov] (HTML FTW!) says, it's "an advanced propulsion physics laboratory, informally known as "Eagleworks"" being implemented by NASA Johnson Space Center (NASA/JSC), so it is part of NASA.
Re: (Score:2)
You read it here first!
All speculation (Score:2)
If it really does work (and extraordinary claims do require extraordinary proof) we have absolutely no idea how. The current explanations do not make any sense within known science. Who knows, maybe we have stumbled onto a way of directing dark energy. At this stage, I am not dismissing the possibility that it is the science discovery of the century, though I still consider it more likely than not that further study will debunk it.
Re: (Score:2)
Re: (Score:2, Informative)
You can't just "use the name" of any government agency unless you are properly affiliated, or the man will drop the hammer on you hard.
Re: (Score:2)
Except NASA doesn't have the budget for lawyers... (que super sad music)
Re: (Score:2)
queue, not que (which is spanish for what).
NASA isn't reputable?? (Score:3, Interesting)
Eagleworks is NASA's "check weird shit and see if its real" department, so they are exactly the place to check this.
How is this any different from "magical force that synchronizes photons across space and time.... but only if I pre-filter the results of my experiments before shoving them into my statistical test"?
Higher physics is absolutely full of magic pseudo science shit, and this might be something real and simple, that just isn't understood by the current bogus nature of magic fluffy physics.
Re:What is this, Omnidot? (Score:5, Informative)
The Eagleworks paper has already been accepted [ibtimes.co.uk] by the AIAA [wikipedia.org], which could fairly be described as "reputable". It will appear in the December 2016 issue.
Re: (Score:2, Interesting)
If you use 1 kW to generate photons and use them as your rocket exhaust, then you produce (1 kilowatt / speed of light) = 0.00334 millinewtons. This EM drive produces 360 times more thrust, so it can't be explained that way.
Re: That's easy. And it doesn't violate the 3rd pr (Score:3)
Here's the thing people that don't really understand the physics don't get. Mass is energy energy is mass. If you're throwing photons out the back that you are creating then you are ejecting mass.
While a photon rocket is efficient in terms of mass it's actually terrible in terms of the energy required to accelerate something.
Re: That's easy. And it doesn't violate the 3rd pr (Score:5, Informative)
That's not why the EM drive is neat. The force provided by emitted radiation is a fairly well understood and predictable phenomenon. The EM drive has a sealed microwave cavity, so it doesn't emit many photons, and those that it does through thermal radiation are measured and accounted for. Despite that, the EM drive appears to produce an additional force, that is what makes it neat.
Re: (Score:2)
Yes I understand that. I probably should have made it clearer, but I was replying to the original poster explaining to him why his idea of "just bouncing around photons/internal solar sail" isn't what an EM "reactionless" drive would be since it would still be ejecting mass and the rocket would be getting lighter just like any kind of rocket would.
I was about to do a back of the envelope calculation on the energy requirements of a traditional photon rocket, but it looks like a poster ahead of me just did. 1
Re: (Score:2)
Here's the thing people that don't really understand the physics don't get. Mass is energy energy is mass. If you're throwing photons out the back that you are creating then you are ejecting mass While a photon rocket is efficient in terms of mass it's actually terrible in terms of the energy required to accelerate something.
Argh. More people who think they understand physics without ever having studied it.
Light does NOT have mass. But it does have momentum. And that momentum is what can be used to produce force.
But how can it have momentum without having mass? To understand that, STUDY PHYSICS. I mean the hard mathy stuff, not the hand wavey stuff.
Even in Europe this is Wrong (Score:4, Informative)
Here in Europe (specifically Germany) we always say a photon has mass because E=mc^2 but its rest mass is 0
No we do not say this in Europe and none of the Germans I have worked with at CERN have ever said this either because it is provably wrong. Photons have momentum but no mass. Either you had a really bad physics teacher or you did not understand what you were being taught. For a photon E=pc where 'p' is the momentum.
Re:Even in Europe this is Wrong (Score:5, Interesting)
If it has mass, how can it travel at c?
It doesn't, but not for that reason.
A simplified answer is that because it travels at c, spacetime doesn't apply to it, only to what it passes through. c is an asymptote, which other particles can only approach. Photons live inside the asymptote, and are not subject to the standard rules for what occurs.
In E=mc^2 (or the general expanded version), "c" is a constant for distance divided by time. As Einstein discovered, time itself is suspect - it varies. Which is fine as long as you only approach c, because distance compensates exactly. But when time no longer approaches zero but is zero, "c" becomes infinity divided by zero, which is meaningless. A single photon is then everywhere, anywhen, which doesn't match our observations.
We can only assign a photon "mass" through equivalence - what mass changes occur when a photon is created or destroyed. While[*] it exists, it's meaningless to assign it mass, but it's meaningful to assign it a mass change potential, or momentum.
[*]: Also a meaningless term for a photon, as a photon's life span is instantaneous or infinite, never anything in-between. Any "while" only affects the surroundings, not the photon itself. It laughs at clocks.
Re: (Score:3)
There is nothing new to be discovered in physics now. All that remains is more and more precise measurement
-- Lord Kelvin, 1900, when people still believed in the luminiferous aether.
What physics revolutions appeared in the early 1900s, do you think?
Re: (Score:3)
Yes, and none of the paper authors are related in any way to Shawyer or Fetta. You know, like in the definition of "independent".