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New Test Supports NASA's Controversial EM Drive
An anonymous reader writes: Last year, NASA's advanced propulsion research wing made headlines by announcing the successful test of a physics-defying electromagnetic drive, or EM drive. Now, this futuristic engine, which could in theory propel objects to near-relativistic speeds, has been shown to work inside a space-like vacuum. NASA Eagleworks made the announcement quite unassumingly via NASASpaceFlight.com. The EM drive is controversial in that it appears to violate conventional physics and the law of conservation of momentum; the engine, invented by British scientist Roger Sawyer, converts electric power to thrust without the need for any propellant by bouncing microwaves within a closed container. So, with no expulsion of propellant, there’s nothing to balance the change in the spacecraft’s momentum during acceleration.
I want a non-Newtonian drive as much as any other nerd out there, but it's still more probable that (assuming it works) it uses conventional physics, just in ways they haven't figured out yet.
That said, I think this result is the point where NASA, DOD, Lockheed Martin, Boeing et al should turn on the money spigot for research. There's obviously something going on, even if it's just conventional physics in unexpected ways. And on the odd chance it *is* new physics, the results could change the world.
They've gone into plaid?
In Dr. White’s model, the propellant ions of the MagnetoHydroDynamics drive are replaced as the fuel source by the virtual particles of the Quantum Vacuum, eliminating the need to carry propellant.
Let's see: we can violate conservation of momentum by invoking some sort of vaguely defined quantum woo. Riiiight. Where do I send my check?
I see you like to comment on something without reading it.... try taking a look at the article... it says specifically that conservation of momentum is NOT violated...
Well the tests keep showing the damn thing works! Maybe it's just magic. Works based on fairies flying out of an engineer's butt, or something. Hopefully it doesn't break the universe :-/
I'm trying to teach myself to set people on fire with my mind... Is it hot in here?
I see you like to comment on something without reading it.... try taking a look at the article... it says specifically that conservation of momentum is NOT violated...
Well, the article says it, so it must be true.
If you're not throwing anything out of the back of the rocket, you're violating conservation of momentum.
When it spends 99% of its launch mass lifting itself to orbit, you have a bad system. Nice to see people trying to think outside the box.
Technically, they're keeping it all in the box.
The cesspool just got a check and balance.
I am willing to accept that maybe they have found a corner case where Virtual Particles can be converted to real particles and used as fuel, since it's basically just converting energy back to mass to be used a propellant. That's not a violation of the laws of physics, it's just reversing the normal flow of matter in to energy.
That being said, the claims of 'warp bubbles' being suspected I am skeptical about. They are going to have to show me a dozen of independent tests before I am willing to get my hopes up about possible FTL applications.
Extraordinary claims require Extraordinary evidence.
Let's see: we can violate conservation of momentum by invoking some sort of vaguely defined quantum woo. Riiiight. Where do I send my check?
The practical result says that it works anyway.
I suspect that there is a balance in physics somewhere... just that no one knows where or what that is yet.
I am kind of curious though - does it have the acceleration curve of a VASMIR/Ion engine, or can we build something with it that will give greater speed in less time?
(...also, is the acceleration graph linear, curved sharply in either direction, hits a curve at a certain point... what?)
Quo usque tandem abutere, Nimbus, patientia nostra?
If nobody knows how it works, how did the guy invent it?
This posting is provided 'AS IS' without warranty of any kind, implied or otherwise.
Don't write "physics-defying", this is not a tabloid for uneducated morons, or is it? Nothing is physics-defying, motherfucker.
Nice snark. Explain why they're still seeing observed results in testing then. The latest test in a vacuum chamber is the interesting one as a lot of people expected it to fail as they surmised the other teams were observing thrust from convection. Now that it has succeeded, things look exciting. Obviously it doesn't violate the physical laws of the universe, but it's also apparent nobody knows WHY it works just yet. More study is needed.
In Dr. White’s model, the propellant ions of the MagnetoHydroDynamics drive are replaced as the fuel source by the virtual particles of the Quantum Vacuum, eliminating the need to carry propellant.
Let's see: we can violate conservation of momentum by invoking some sort of vaguely defined quantum woo. Riiiight. Where do I send my check?
Although I haven't seen the math or read the articles yet, the above sentence makes sense to me. Instead of inputing energy to fuel and kicking out the back, they input the energy to the virtual pairs that are in all space. That gives the drive it's thrust as they are pushing against the virtual pairs which then recombine and cease to exist. However, when they cease to exist, they should still have a higher net energy over free space which would result in EM radiation being released when the virtual particles cease to exist. They might not cease to exist and thus the new particles never recombine and become actual particles, but the energies of the two particles (minus what was inputted into them) would be opposite of each other.
Actually, the test shows that is not fairies flying out of the engineer's butt, but rather invisible unicorns pushing the unit. Those tricky magical bastards....
I suspect that there is a balance in physics somewhere... just that no one knows where or what that is yet.
This.
Just because we can't see the balance doesn't mean it isn't there.
My guess is it's the same sort of testing magic the latest cold fusion dude in italy is peddling.
Some drink at the fountain of knowledge. Others just gargle.
This might be another Cold Fusion moment. Or, it might be the start of something very interesting.
When an experiment contradicts a theory, there are two possibilities: (1) there's something wrong with the experiment; or (2) there's something wrong with the theory. If the correct answer is (1), then it's par for the course: mistakes happen, and the process of science corrects them eventually. But if the correct answer is (2) then it's cork-popping time, because you have discovered new science.
If it weren't for deadlines, nothing would be late.
There is no law of physics that says physical propellant is necessary. Any light bulb and mirror can create momentum, with no propellant expended. SF writers have known for a long time that, in principle, electromagnetic effects like powerful lasers can create thrust. I need more details to make sense of this article.
That is what peer review, replication of results and further study are for...and I am biting my lip not to add "dumbass" to the end of that sentence.
And BTW: those things are already happening. Other scientists are critiquing (constructively rather than your sort of nonsense) and others are carrying out new experiments in the same and novel situations to eliminate confounds. You know, the scientific world doing what they do.
What I find absolutely amazing here (apart from the *potential* discovery) is how everyone is more interested in bagging on the science than commenting on how this might be a major breakthrough after NASA (FFS) has been confirming the results.
Yes, it may not be as it is. But it is also WAAY too early to cry foul.
Some days the internet its like watching a tribe of chimps...
It is the same as if you are locked in a cage and bump yourself against the wall - the cage eventually moves. yet nothing is expelled outside of the cage.
Doesn't that only work because of static friction though? Bump hard enough to break the static friction and scoot across the floor, then move slowly when reversing such that you don't break the static friction on the way back.
(...also, is the acceleration graph linear, curved sharply in either direction, hits a curve at a certain point... what?)
As long as you don't change power input, acceleration is always linear.
No idea why you ask this, that is a no brainer.
Cost free eBook I read (by iBook/Kobo/Amazon/ObookO/Gutenberg etc.): "The Green Odyssey" by Philip Jose Farmer.
They say one of the limiting factors (aside from violating the laws of physics) is the political will to launch a large nuclear power plant into space. The solution is obvious: use Cold Fusion to power the EM drive. There is great efficiency here because they can get two Nobel prizes with only one gadget.
We don't see the world as it is, we see it as we are.
-- Anais Nin
If two magnets get close enough and snap together are they violating conservation of momentum when forces are acting on them to accelerate toward each other?
Of course not. The total momentum of the system stays zero.
When I was a kid, I tried to make a self-propelled car by putting magnets on the back and front bumpers of a toy car, reasoning that the front magnet would attract the back one, and therefore produce thrust. When I built it, I learned a valuable lesson: it doesn't work. Because the force pulling the back magnet forward is exactly counterbalanced by the force pulling the front magnet backward.
The EM drive is closely analagous to this idea. Except that they didn't figure out when they were eight that this will never work.
The inventor knows.
He formulated the theory of the device. And actually it is pretty easy to grasp for a layman. http://en.wikipedia.org/wiki/E...
Can't be so surprising that a scientist draws/imagines a "thing" and engineers build it and: surprise, surprise, it works like the scientist thought it out. (*facepalm*)
The creationists must have done good work in america to destroy the "faith" in science!
Cost free eBook I read (by iBook/Kobo/Amazon/ObookO/Gutenberg etc.): "The Green Odyssey" by Philip Jose Farmer.
A lovely summary from the Physics StackExchange which sums up my thoughts:
"The initial tests were at atmospheric pressure. To test the fan hypothesis, an easy way is to vary the pressure, another easy way is to put dust in the air to see the air-currents. The experimenters didn't do any of this (or at least didn't publish it if they did), instead, they ran the device inside a vacuum chamber but at ambient pressure after putting it through a vacuum cycle to simulate space. This is not a vacuum test, but it can mislead one on a first read.
In response to criticism of this faux-vacuum test, they did a second test in a real vacuum. This time, they used a torsion pendulum to find a teeny-tiny thrust of no relation to the first purported thrust. The second run in vacuum has completely different effects, possibly due to interactions between charge building up on the device and metallic components of the torsion pendulum, possibly due to deliberate misreporting by these folks, who didn't bother to explain what was going on in the first experiments they hyped up. Since they didn't bother to do a any systematic analysis of the effect on the first run, to vary air-pressure, look at air flows with dust, whatever, or if they did this they didn't bother to admit their initial error, this is not particularly honest experimental work, and there's not much point in talking about it any more. These folks are simply wasting people's time."
http://physics.stackexchange.com/questions/23725/is-the-emdrive-or-relativity-drive-possible
In conclusion, they did a really really bad experiment and got a bad result. Wow!
was based on the physics of this theory. So real world results will prove very interesting when time travel is thrown into the equation.
The other thing you get when you generate RF is eddy currents in nearby materials, generating magnetic fields from nearby materials. Nothing to see here, move along...
Instead of inputing energy to fuel and kicking out the back, they input the energy to the virtual pairs that are in all space.
"Impulse Drives" don't work by pushing "against something".
Cost free eBook I read (by iBook/Kobo/Amazon/ObookO/Gutenberg etc.): "The Green Odyssey" by Philip Jose Farmer.
Try NASA or the guy that invented it.
I prefer the "u" in honour as it seems to be missing these days.
Or maybe, as the case was here, you document your experiment in a paper, publish it through proper channels, then science reporters get wind of it, blow it out of proportion and completely distort what you said, then someone else links to that distortion on an internet forum.
Impulse Power Mr Cuthulu!
Well the tests keep showing the damn thing works! Maybe it's just magic.
If it is based on magic, then scientists are ill prepared to detect that. Instead you need a professional magician, who is skilled in the art of deceit and deflection. Is James Randi available?
Asking because apparently no one knows just yet exactly *why* this thing is putting out, err, 'thrust'. They know how, well, sort of...
Quo usque tandem abutere, Nimbus, patientia nostra?
this gem ... hidden in the article:
"... whether it is possible for a spacecraft traveling at conventional speeds to achieve effective superluminal speed by contracting space in front of it and expanding space behind it. ..."
They've been playing at that for a while. It would allegedly work by creating a condition of cosmic expansion behind the craft and its converse in front of it, so the spacecraft is in a bubble where it's running slower than lightspeed (i.e. stopped) but the cosmic expansion and contraction regions behind and ahead of it each total to the opposite sides retreating or advancing faster than light (which is allowable).
I'm not holding my breath waiting for that to fall out of this - or anything. Effective superluminal translates to "Sending messaages into the past." and "Violating causality." if you pick your reference frames correctly. So I expect flies to appear in this ointment at some point: Like something broken about what happens at the sides, needing big-bang energy levels (and not being able to transfer them between the front and back so they're free), or not being able to set up the condition in front because the agency making it happen must involve actual superluminal signal propagation.
Nevertheless, an "electric motor" that works by pushing against virtual particle-antiparticle pairs (or the total mass of the matter in the universe, or of an inverse-square weighting-by-distance of it so it's mostly the local stuff, or dark matter, or the neutrino background, or whatever), instead of ejected exhaust, is just DANDY! Let's see if they can make it work for real at human-palpable, nontrivial, efficiencies and power levels.
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
https://xkcd.com/1404/
I see you like to comment on something without reading it.... try taking a look at the article... it says specifically that conservation of momentum is NOT violated...
Well, the article says it, so it must be true.
If you're not throwing anything out of the back of the rocket, you're violating conservation of momentum.
So... You're now arguing that you can violate the conservation of momentum. Interesting.
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There's nothing currently practical about it. It's in the experimental stage. If we had a spacecraft flying around on one of these, I'd be much more confident. The last time an observation violated the laws of physics like this, it turned out to be a loose cable connection.
By Noether's theorem, if we're violating the law of conservation of momentum, the laws of physics must vary from place to place in the Universe. (Unfortunately, I don't understand general relativity well enough to generalize this.) If this actually works, we're going to need a rewriting of physics comparable to Special Relativity. We definitely should push ahead with testing this thing, although I still think it's going to turn out not to be a reactionless space drive.
"When you have eliminated the unacceptable, whatever is left, however improbable, must be the truthiness" - Holmes
He's asking if 2x the electricity means you get 2x the speed.
"I like to lick butts!" by MobileTatsu-NJG (#32700246) (Score:5, Informative)
This would be really awesome and exciting if it really worked, but, well, it's apparently challenging models of physics which have withstood a tremendously diverse battery of scientific tests. Smart money is on the measurements being a mistake with the experimental apparatus.
More like tests keep showing that it IS working, and nobody is sure why. Either the problem is with the test, or there's something else happening that we don't understand, but either way, nobody is sure yet what's going on.
I think it's likely that the test is faulty, but they need to figure out why or how the test is faulty.
Area man refuses to accept that something was demonstrated by a scientific experiment can possibly be true - insists that his knowledge of science as an 8 year old was more advanced than that of actual actual specialized scientists.
The inventor knows.
He formulated the theory of the device. And actually it is pretty easy to grasp for a layman. http://en.wikipedia.org/wiki/E...
Have you actually read the paper? Hint: there's a very, very good reason why it is not in a peer-reviewed journal.
That's just silly. The people reporting this observable phenomenon do not claim to understand why this happens - in fact the point of the article is that we should strive to understand why this works.
Just because YOU don't understand why this works doesn't mean that they are claiming to be violating the conservation of momentum - especially since they are not. Most especially because there's a clear expenditure of input energy - a grossly inefficient (it would seem) one.
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What are we calling "propellant"? It requires power to generate the radiation. How is this diff than say an ion engine? It needs SOME energy source, just not necessarily traditional sources such as flammable chemicals.
And as the radiation bounces around inside the Gumby-head-shaped chamber, it does lose some energy on each bounce such that the radiation generator has keep doing its job.
What's unknown is if we get "bonus" energy beyond what say an ion engine can do with the same amount of electricity.
The speculation is kind of like cold-fusion for space: direct matter-to-energy conversion without the messy side-effects such as high temperatures and dangerous radiation found in traditional nuclear reactors.
Table-ized A.I.
For the physics you can google yourself. /. since 3 or 4 years, and the physics is published since at least 2000, which was 15 years ago if you are bad in math, it should not be difficult for you to figure how the drive is "supposed" to work.
As articles about the EM drive are showing up on
How exactly do you want to be spoon fed? If you have not even read up the basics, what exactly do you ask me to tell you about it?
When somebody sounds like a total fucking crackpot, they almost always are.
Did not know that NASA is meanwhile down to crackpots. (Regarding the EM drive)
Or that the US Navy is now down to crack pots as well. (Regarding cold fusion)
You must have a strange definition of "crackpot" ... or must live in some basement playing counterstrike all day and night.
(If you want to know how to get banned from a server by doing 10 head shots in a row, obviously without cheating, I tell you ... it is super simple)
Cost free eBook I read (by iBook/Kobo/Amazon/ObookO/Gutenberg etc.): "The Green Odyssey" by Philip Jose Farmer.
Correct.. But you can jump inside the case as well. When you are not into contact with it, it just transfer your momentum. Imagine that you apply X amount of momentum when you are inside the case to bump into a wall, yet apply only half to return to the center of the cage. At the end you have X/2 momentum applied over the cage wall for your entire movement. If you use waves to carry particles, or accelerate particles through EM, you can do the same. Accelerate them for a time X till they bump into the container, then accelerate them back with X/2 to move them back inside.. Since the container is heavy you can't accelerate it with the EM changes, only the particles inside, then repeat.. Not very effective, but with a big and light container and a lot of particles inside (you want them to stay inside) the container will eventually get moving even in the frictionless environment of space. And the nice part it you can actually leave some of the effort to return the particles to their original positions to diffusion. All you have to do is manipulate where in the volume the mass is and how it is distributed.
Everybody's busy bagging on the science because reactionless space drives are known to be impossible, and if it turns out this is actually one, it's going to be a real interesting time to be a physicist because some really basic assumptions are going to have to be replaced.
The chance that this is due to some systemic experimental effect that nobody's noticed yet is still way higher than the chance that this actually works as advertised, so it's WAAY too early to cry fair either.
"When you have eliminated the unacceptable, whatever is left, however improbable, must be the truthiness" - Holmes
Why do you keep saying this? They aren't giving an answer. They don't understand why it works, they clearly suggest that we should figure out why it does...
You seem to be building a straw man argument so you can rant about the COM.
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If I were to peer-review a paper on this, I would insist on a plausible physical explanation for the claimed measurement. The burden of proof is on them: they are making a truly extraordinary claim, one that, if true, would entail revising all of physics from its very foundation.
When somebody sounds like a total fucking crackpot, they almost always are.
You might have missed high temp super conductivity entirely then. The phenomenon was measured and replicated in many labs - but it was at least a few years before any plausible theory came out - and 20 years on we do not have firm agreement on the cause.
They power up the device, and apparently it works by providing thrust somehow. What fault? I really need one of those for my car ASAP.
Except he in involved with all the tests and sets the parameters. This has been replicated by 3 different teams using their own manufactured cavity chambers and one of those teams works for NASA. Just a wee bit of a difference.
Or, rather than all of physics being wrong, maybe they have an erroneous measurement setup.
That doesn't mean you shouldn't investigate anomalous measurements. But at this stage you shouldn't be writing fluff pieces with page after page of how much your new technology will change spaceflight. You should be publishing a paper with a name like "Measurement of anomalous thrust in a microwave apparatus operated in a hard vacuum" and trying to avoid the media insomuch as possible - and when you need to talk with them, trying to explain "we don't know what's going on... we have some theories but they're controversial... we need to do more testing." etc.
Sigur RÃs: I didn't know that Heaven had a rock band.
I wonder if radiation pressure from the solar panels supply the power would alternatively augment or inhibit the effectiveness of this drive.
That's just silly. The people reporting this observable phenomenon do not claim to understand why this happens - in fact the point of the article is that we should strive to understand why this works.
They're measuring an anomalous force in an electromagnetic cavity. That's a measurement, a concrete fact. They're claiming that they'll be able to make a starship with it. That's beyond any credibility. It's totally delusional.
Haha, my concept as a child was to have a buoyant container on wheels in a tube full of water that would rise up, roll down a ramp on the other side, and re-enter the tube through an airlock on the bottom.
Wish my dad had taken the time to tell me why it wouldn't work rather than just saying "perpetual motion is impossible".
Sigur RÃs: I didn't know that Heaven had a rock band.
So NASA didn't build the device, they weren't allowed to control the device, they weren't allowed to check the wires going into the device but assumed that the chamber was emptied to a hard vacuum and that the force sensors worked right?
There's no comparison.
There is already a proposed mechanism that doesn't require "revising all of physics from its very foundation".
Send it to Larry Niven. I always wondered how his "reactionless drives" worked, and now I finally und-- actually, no, I don't understand how this works at all.
As copyright owner of this comment, I authorize everyone to defeat any technological measure which limits access to it.
Before we call this real, we need to put one on some object in orbit, leave it in continuous operation, and use it to raise the orbit by a measurable amount large enough that there would not be argument regarding where it came from. The Space Station would be just fine. It has power for experiments that is probably sufficient and it has a continuing problem of needing to raise its orbit.
And believe me, if this raises the orbit of the Space Station they aren't going to want to disconnect it after the experiment. We spend a tremendous amount of money to get additional Delta-V to that thing, and it comes down if we don't.
Bruce Perens.
Does that mean we have to send that blessed engineer into space to power the probe? I'd rather "have to" send politicians. If bullsh1t turned out to be a powerful propellant, we could hook it up to the bozo's in Washington DC and visit Andromeda.
P.S. don't walk into the EMD lab wearing a red shirt until they find out how it works.
Table-ized A.I.
Um.. "The EM drive is closely analagous to this idea. Except that they didn't figure out when they were eight that this will never work."
How so?
I mean, it DOES work.. So just because you don't understand it does not stop it from working. Child toy playtime and not understanding things has nothing to do with it.
They also never claim it has anything to do with two magnets repelling each other. It works by pumping microwaves into a asymmetrical resonate cavity. They get thrust. Two main ideas for why this is are that there is either direct interaction with Quantum Vacuum virtual particles so that if functions like a normal ion drive but without having to use stored actual particles for thrust, or perhaps instead it acts like a virtual toroid and that due to the asymmetric group velocity of the microwaves in the cavity the energy 'lost' to the Quantum Vacuum interactions of the virtul toroid must be made up, thus for conservation of momentum to be intact there must be the same amount of thrust as the energy 'lost' to the Quantum Vacuum.
Also, don't forget, regardless of anything else the entire universe is awash with magnetic fields from various sources. So in the end if you had a big enough electromagnet, a large enough power source and an understanding of what fields were naturally present you could propel yourself anyplace in the universe with it.. No strings or propellant needed.
If you learn of an alleged unusual phenomenon, and you have an immediate rigid response, please stay away from science. Go into religion or politics. The only appropriate response is "Hmmm interesting, let's look into this". Human knowledge is always provisional. Careless, absolute, knowledge claims are the currency of religion.
Seriously in the links provided there was absolutely nothing that made it possible to evaluate the claims.
Nope, they're not. It's generating three orders of magnitude more thrust than would be generated merely by the momentum of emitted microwaves.
"If I were to peer-review a paper on this, I would insist on a plausible physical explanation for the claimed measurement." That's stupid. Providing proof that something interesting is happening and repeatable is viable science all on its own. I've read quite a lot of highly-respected papers from highly-respected people in highly-respected journals which did nothing other than document a pattern of behavior without explanation. In fact, most scientists I know will say they rarely ever really think they know *why* something happened, but that doesn't stop them from wanting to know. Some things get thousands of perfectly cromulent papers written prior to anyone really having a firm grasp on the "why" - hell, if you have the "why" then you probably have the last paper that will ever need to be written on the subject. Even farking *gravity* is still a bit of a mystery. We're pretty good on exactly *how* it works, but the *why* that you insist is necessary, for even something we all pretend to understand, isn't really yet known.
So it's powered by a typical Comcast bill
Table-ized A.I.
There's no 'seem to be' about it. That's exactly what he's doing.
There are two types of people in the world: Those who crave closure
To an outside observer. I don't think it's the same in the inertial frame.
Bruce Perens.
I prefer Penn and Teller. Much more entertaining.
Yes it's an anecdote! Were you expecting original research in a Slashdot comment?
"If I were to peer-review a paper on this, I would insist on a plausible physical explanation for the claimed measurement." That's stupid. Providing proof that something interesting is happening and repeatable is viable science all on its own.
If they simply wrote a paper saying "we noticed an anomalous force in this experimental setup, and we don't understand why", then nobody would have a problem with it. They're not doing that. They are claiming that it can be used as a reactionless propulsion system, a claim which is entirely incredible without a solid physical theory to justify it.
So, you're limited to, what, 5000 characters and can't/won't/haven't pointed it out?
Stop making vague insults and actually say something meaningful for or against the theory or test. Because you haven't come close to that yet.
There are two types of people in the world: Those who crave closure
Except the test results seem to indicate that it does.
But then you are a world class physicist and know better than this NASA team that's been testing this device for years, eh?
Wouldn't a more reasonable person think that there must be some interesting physics going on here instead of poo pooing the idea like a modern day Baron Kelvin.
When Fascism comes to America, it will call itself Anti-Fascism, and tell you to give up your guns.
Over 27,000 cycles of data (each 1.5 sec cycle energizing the system for 0.75 sec and de-energizing it for 0.75 sec) were averaged to obtain a power spectrum that revealed a signal frequency of 0.65 Hz with amplitude clearly above system noise. Four additional tests were successfully conducted that demonstrated repeatability.
Is that enough?
When Fascism comes to America, it will call itself Anti-Fascism, and tell you to give up your guns.
> When somebody sounds like a total fucking crackpot, they almost always are.
At this point, we need to ask if he does indeed sound like a total crackpot.
A crackpot would say: "THIS WORKS! By mechanism xyz, this Definitely works, and you should PAY ME!"
A real scientist would say "Umm, when I do this, it does that. Anybody know why? This doesn't make sense." Then, with enough people saying the same, things get exciting.
The question is, are we the former or the latter? The former sounds like Rossi with his e-cat. The latter sounds like this situation. I think we're just starting to get to the exciting phase; let's hope we get more experiments to confirm what we think is happening is really happening.
Tests are showing the damn thing works. When the Chinese said worked I would have rather believed there where fairies flying out someones ass. But now that NASA tests are showing repeatable results there might be something here.
But no matter what, if the damn thing does work, it does not defy the laws of physics. It might work based on some laws we don't understand or some principal that we haven't thought of. But it isn't magic.
Supporting World Peace Through Nuclear Pacification
Why not discuss the current experiment setup and results in an online forum? If the experiments pans out, then publish in a journal.
If Mr. Edison had thought smarter he wouldn't sweat as much. --Nikola Tesla
> Except that they didn't figure out when they were eight that this will never work.
This one goes to 11.
The expulsion (should that not be expulsion or something?) are micro waves ...
hence the name: EM drive.
What you are describing is a photon drive where photons are the propellant. But the fine article explains:
After consistent reports of thrust measurements from EM Drive experiments in the US, UK, and China -- at thrust levels several thousand times in excess of a photon rocket, and now under hard vacuum conditions -- the question of where the thrust is coming from deserves serious inquiry.
The reason I don't believe it is real is the same reason I don't believe cold fusion is real. They put in metric ton-loads of energy and measure a very small effect. They say they will need to increase the efficiency by many orders of magnitude to create a practical device. I say they probably made a mistake somewhere and the tiny effect they measured is either noise or due to something else they haven't yet accounted for.
We don't see the world as it is, we see it as we are.
-- Anais Nin
Whatever happened to those guys?
When Fascism comes to America, it will call itself Anti-Fascism, and tell you to give up your guns.
again, we can have a very good grasp on *what* without having a grasp on *why*, as in the example I gave: gravity. We use it as a law, it's an accepted thing in nearly any super-particle physics, yet we don't really know *why* it works. And again, as soon as we know *why* something works, that's the last paper that will ever need to be written on the subject. Every paper should explain how to repeat the experiment, with observations about the experiment. You're demanding of this paper something few - if any - papers in the history of science has ever attempted to accomplish.
Piffle, you don't need a theory to prove it works. Build a test engine in a microsat, release it in orbit, point it at the moon and fire it up. If it sits there and sputters, then yeah it's probably bogus, if on the other hand the thing accelerates for a couple of days then slams into the lunar surface, well then you've got grant money for the next 30 years easy.
from "The hobo guide to travelling the galaxy"
After a certain amount of many many many yrs. and hopefully not your energy source running out you will have gained mass by speed without jogging and not by eating:
but relativistically which is why it is sooo hard to reach even near relativistic speeds[1].
So with this "flash light" with a certain amount of power and energy (and direction) you can travel the universe.
Back to topic:
So the described idea is basically that of a "photon gun" or flashlight or microwave gun
Micro waves are "also" part of the electromagnetic spectra therefore we can ask them "wave" or "particle" and they will answer "trans" and decide politcally correct in a s(p)lit to interfere into a figure of light and shadow.
But therefore the laws of physics still apply:
Photons have a mass equivalent to their energy the energy of a photon can be descbribed by it's frequency, the higher the frequency the higher the energy the higher the mass and if there is mass there is an impulse.
final advise to travel the universe with a flash light, a wodden back plate and some mylar sheets:
And for goods sake if you're in space use a monochromatic high power photon gun (L.A.S.E.R.) or a (M.A.S.E.R.) or a Magnetron for propulsion. Not an old flash light!
And use some solar sails where solar sailing is ultimatly cheaper.
rubber bullet point
And if you want to be initially driven by your friend standing on the moon shooting with objects at you, demand (s)he takes elastic objects like a rubber ball and make sure to have your solid deflection plate perpendicular to the intended flight vector but between you and the "ball" otherwise your journey start will be painful or deadly (but it would work, however not that good)
And if you think after all these experiments that you have violated the laws of physics .. No you don't have.
physical bullet points to rubber ball propulsion
The rubber ball will transmit force when hitting you and when bouncing off instead of an inelastic object (Elastic collision)[2].
- "solar sails"
- photonic impulse
[1] http://en.wikipedia.org/wiki/M...
[2] http://en.wikipedia.org/wiki/E...
At the same time, when you hear hoofbeats, you think horses, not zebras.
The problem we're having is a whole bunch of people claiming we have unicorns.
Let's wait and see what happens before we all go to Mars, eh?
Not believing a word of this till they let some practical types have at it. Scientists are really easy to trick - just ask Penn and Teller.
Uh, no. Eagleworks is the name of an experimental propulsion lab that is part of NASA. It's located in Johnson Space Center. It is not a "private shop".
Why the fetishistic obsession with balance? Isn't anti-symmetry the reason we exist at all?
You might have missed high temp super conductivity entirely then. The phenomenon was measured and replicated in many labs - but it was at least a few years before any plausible theory came out - and 20 years on we do not have firm agreement on the cause.
Poor comparison. High-Tc superconductivity was a demonstration of a known phenomenon (zero resistance current) under new physical circumstances. A better comparison might have been the photoelectric effect, which really had no explanation under the then-known laws of electromagnetism. The explanation for the photoelectric effect in fact did require a deep and radical revision of the basic laws of physics: Quantum Mechanics. Sometimes this happens.
These guys have not measured something which clearly requires such a revision of physics, yet they are full of breathless claims about its significance. Red flags all over the place.
Well, to be fair, when someone notices that their experiments repeatably cause propulsion, it's probably not a huge stretch to say it could have applications in propulsion even if we don't know how it works. Hence the "further discussion" section of most scholarly journals.
"If I were to peer-review a paper on this, I would insist on a plausible physical explanation for the claimed measurement." That's stupid. Providing proof that something interesting is happening and repeatable is viable science all on its own. I've read quite a lot of highly-respected papers from highly-respected people in highly-respected journals which did nothing other than document a pattern of behavior without explanation. In fact, most scientists I know will say they rarely ever really think they know *why* something happened, but that doesn't stop them from wanting to know. Some things get thousands of perfectly cromulent papers written prior to anyone really having a firm grasp on the "why" - hell, if you have the "why" then you probably have the last paper that will ever need to be written on the subject. Even farking *gravity* is still a bit of a mystery. We're pretty good on exactly *how* it works, but the *why* that you insist is necessary, for even something we all pretend to understand, isn't really yet known.
Dr. Schweitzer will tell you the same thing. She found what looked like soft tissue in a T-Rex bone back in 1993 and published her results, in shock herself and knowing that it was impossible to really be that. She checked and rechecked to rule out contamination and other causes, never finding one. The entire scientific community though refused the possibility it was soft tissue because Schweitzer couldn't explain how it could be preserved. By the year 2000 though she'd found the same results from enough other fossils that she's finally getting some traction and it's now starting to be taken by others as true, and there is new research now into how the heck it has happened. Not many people would carry that a decade.
Shaping quantum vacuum states was covered in my graduate quantum mechanics class many years ago - by an experimental spectroscopist who was doing it in his lab. This isn't something your average rocket scientist will know about, but mucking around with the vacuum state is well established in physics.
Since the device is a thruster, the question should probably be interpreted as asking whether 2x the electricity means you get to velocity k in 1/2 the time. And, well, since no one really knows how any thrust at all is being generated off virtual particles, it's conjecture that the thrust output scales linearly with electricity, though "locally linear" makes sense, with some likely non-linear relationship at absurdly large scales of electricity.
This reminds me of an article that was posted in Omni magazine back in the 1980s about a company that noticed that an electrically charged metal structure lost weight when it was electrified. The weight loss was not significant but was measurable.(The Omni article called it "antigravity" but it was actually more like electrostatically caused air movement.) The company marketed the technology as an air purifier, seeing as it ionized the air that was passing though the structure and caused an increase of weight in some of the particulate matter in the air.. causing it to either stick to the metal structure or to drop out of the air.
On Youtube there are countless hobbyists who make serpinski style triangular frames of cardboard and aluminum foil and light wires and charge them with an external power supply and note they are "lifters" the amount of thrust is tiny though, not nearly big enough to lift the power source, to say nothing about using it to power a craft to leave the atmosphere or achieve escape velocity. I don't remember where I read it, but I do think it was in Scientific American that the "Lifters" lift was attributed to electrostatic movement of air through the structure and would do nothing in the vacuum of space. (Best buy does have some nice indigo colored fan "rings" that work this way and that are silent because they have no moving parts.I also think that this is the same technology that was supposedly used in the Red October's "Magneto hydrodynamic", "Silent running" drive, and I have heard that something like that was actually used in submarines.) This may be different, though a peer review is needed and some alternative methods of testing are needed to differentiate what is happening here apart from the various notions about what could be happening. This is part of the peer review process to determine what the properties of such a propulsion method are so we can know if it is viable for space travel. My guess is that this is not something that would allow you to build a flying car or anything like warp drive, more like impulse power in theory, but would produce an amount of force close to the weight of a business card on a spacecraft, in Earth gravity, that is.
I am forced to wonder as an electrical engineer, if they are using strain gauges to measure the amount of thrust.. as I understand it, Strain gauges use metal traces that are of a known capacitance the way they are placed on a material and any slight amount of distortion of the surface it is mounted on causes a predictable change in this capacitance, which is how most electronic bathroom scales measure your weight. I wonder if the electrical field of this type of device would mess with the capacitance in their detector.. provided they are using that method of measuring thrust.. it might be a measurement error due to the method they are using to gauge the amount of thrust.
It is funny though, the part of my brain as a kid that loved Doctor Who is forced to wonder, if in a pinch The Doctor could fashion an "impulse thruster" out of the Klystron of an old microwave. I do know this, Those devices are dangerous, point it in the wrong direction, you can cook body parts. Don't try this at home! In a class in my Bachelor's degree we literally "Nuked" grapes in mid air with a Klystron under controlled conditions and, it burned the grape so intensely hot that it created a pinkish glow.. which was Plasma! Don't point this space drive at your junk, was the takeaway I would add. Not to say that all the people that are paranoid about electrical fields from cellular phones and high transmission lines cause cancer are right.. that has been thoroughly debunked. (and I am not interested in hearing from people who believe that I am wrong about that.. The amount of energy put off by a cellular phone transmitting at full power is not even 1/10th of what is needed to even pop a kernel of popcorn.. or even get it perceptibly warm for that matter. It is funny though that they say oh "Cellular phones on planes can cause all kinds of electrical inte
The system bounces microwaves inside a cone. When a photon hits the base of the cone, that pushes the vehicle forward as it bounces backwards. But the conical shape means that the next "bounce" of the photon will be distributed between a sideways movement and a small backwards movement. But because of the circular shape of the cone, the sideways movements cancel out. The forwards force is greater than the backwards force, so the final velocity is forwards.
Vintage computer adverts: http://www.vintageadbrowser.com/computers-and-software-ads
Area man still remembers a couple of guys named Pons and Fleischmann.
"When somebody sounds like a total fucking crackpot, they almost always are."
Aristarchus of Samos sounded like a total fucking crackpot, and if you had called him out your prediction would have been right - for a couple millennia.
What if instead of taking your attitude, the Greeks had devoted their energy to developing better sensors to test Aristarchus's claims about the parallax motion of the stars? Instead of sitting around calling him a crackpot, we could have had an accepted heliocentric model of the solar system some 1800 years before Copernicus.
I'm not a physicist, but could the anomalous force simply be a reaction between electric currents generating the microwaves, and the Earth's electric field? As I recall, wires carrying current generate a force within a magnetic field, and we all live within a magnetic field.
Ha ha, I was 6 I was going to wire a motor to a generator, then connect them via belt, and watch them run forever. Dad explained to me about perpetual motion. Next idea was to take a bunch of one-way mirrors, and make a box of them to trap light.
Right. But this is the era of "one weird trick" and "this revelation shocked scientists" and other wishful thinking. If you can't work "This is the most important video you will ever watch" into the article, nobody will pay attention.
Oliver's law of assumed responsibility: If you're seen fixing it, you will be blamed for breaking it.
If you're accelerating, you're not in an inertial frame.
General Relativity: Space-time tells matter where to go; Matter tells space-time what shape to be.
Area man bases all decisions on the first popular media example that strings to mind.
Correct.. But you can jump inside the case as well. When you are not into contact with it, it just transfer your momentum.
Oops, I meant PMM. I have Lexdysia. My ships travel backward.
Table-ized A.I.
That's not it so much as the fact that pop science "skeptics" don't believe something works until Neil Degrasse Tyson and James Randi say it works.
There is nothing scientific about pop skepticism. It's entirely about hero worship and being a dick.
You are welcome on my lawn.
And what is that reason?
You are welcome on my lawn.
If the observations are confirmed and not explained (which is currently the case), there's still something to talk about. So yes, this again.
Higher Logics: where programming meets science.
With Newtonian physics, if we could find something that wasn't symmetrical with regards to conservation of motion, we have a perpetual motion system and unlimited energy. So far, every process that converts energy from one form to another always has some loss due to friction or heat.
Vintage computer adverts: http://www.vintageadbrowser.com/computers-and-software-ads
Forget the car. I'm packing for Alpha Centauri. By the way, anyone know what the weather is in Alpha Centauri? I mean, will I need a sweater?
You are welcome on my lawn.
So you're one of the swags that believes all physics is right? Puh-leeze lets make up some more shit like dark matter an dark energy to make it so!
Any time you have an assumption based on physical laws, it must be able to be tested and measured and accounted for and predicted, and if the prediction based on those physical "laws" differs from what is observed, one must first, check their math for errors, check their method of measurement and if all of that checks out to be accurate to ask questions along the lines of: "What are the implications of what we have observed and measured and verified here?" or as Einstein asked "What would the universe be like if it operates the way we have observed it to here?" This is what allows science to side step conundrums based on incorrect assumptions and asking poorly worded questions that lead research astray and into asking the "Wrong questions". Before Einstein, the question was "Why does light always seem to be moving the same speed regardless of the point of view or movement of the observer with respect to that light, when we know that it can't?" That is a poorly worded question, because it assumes that what we know, but that we are unable to use to explain what we observe is correct, when it is likely it is not correct. This is why I hate the term "Laws of Physics" because it implies that they way we understand the universe is the way it operates, when these "Laws" are just our shorthand for documenting and understanding what we observe. This is also not to imply that when someone says "This breaks the laws of physics!" that they are pulling a James Dean, rebel attitude and getting something for nothing, it really, most likely means someone does not fully understand the thing they are dealing with and some corrections will be needed to science books of the future. As HAL9000 said in 2001, A Space Odyssey, "The problem can only be attributable to human error."
No that's not enough! I need to know what Penn and Teller say about this or no dice.
You are welcome on my lawn.
Oops, I meant PMM. I have Lexdysia. My ships travel backward.
I think you mean Lexxdysia. (link)
We don't see the world as it is, we see it as we are.
-- Anais Nin
No, not really.. Imagine a box. make it a 2d square to make it simpler. you have sides names a, b, c, d (c is opposite of a, d is opposite of b). Have a few particles in the center.. now accelerate them via EM field towards side a, until they collide with it. They have transferred momentum to side a. Now accelerate them back, towards c, but with a lower force, so it takes them more time to reach c (or just allow them to diffuse because of Brownian motion and skip the next step). Now, before they actually reach c, you accelerate them towards b and d sides with a comb like fields. The particles collide with b and d, effectively cancelling out the momentums on each side, so you reverse the filed until you put them in the center and accelerate towards a again. So at the end, over time you will get a single non-zero vector of the force being applied on a (all others cancel each other out). The tricky part is to be able to split the particles equally in half and collide them in a plane perpendicular to the plane of motion so they cancel each other (or wait long enough for diffusion).. no friction required.
I have an ugly feeling this ultimately involves unpleasantries with cats.
Table-ized A.I.
You might want to look at this nice summary from Reddit of all the experiments performed in China and at NASA about these drives:
The FACTS as we currently know them about the EmDrive and Cannae Drive
How come Slashdot never gets Slashdotted?
But the conical shape means that the next "bounce" of the photon will be distributed between a sideways movement and a small backwards movement. But because of the circular shape of the cone, the sideways movements cancel out. The forwards force is greater than the backwards force, so the final velocity is forwards.
Do realize that after the glancing blow, the photon will continue to move towards the narrow end of the cavity, and continue to bounce against the angled walls, producing a cumulative effect equaling the initial impact on the wide end of the cavity, dropping your net impulse back to zero. Classical mechanics says this doesn't work, so if you want to postulate a theory on its operation, you need to do it using something more complex than classical mechanics.
That's an excellent example. Gravity is still, in some ways, a mysteroius answer. We know a lot about it, and we can use what we know to make a lot of predictions, but we also know there's a lot that we don't know, and some of our theories about its properties are better termed guesses than predictions.
Now, obviously the EmDrive is far more mysterious than gravity, both because it's much more conceptually novel and unexplored, and because we can really easily detect there's *something* causing the effect called gravity while only a handful of labs around the world are equipped to test the thrust of an EmDrive. I'm not attempting to equate the two. But, as you say, the actual mechanism of gravity has never been observed directly, and the theories about it are still unconfirmed. Similarly, the EmDrive offers some (much less mature) theories as to its operation, but nobody has actually been able to confirm or deny those theories.
Of course, the EmDrive itself hasn't been confirmed yet, at least not to the degree that makes it practical for anything real-world. We have repeatable experiments saying that emitting microwaves into a specially-shaped resonant cavity causes a *tiny* thrust, and we've accounted for some of the likely errors in the experiment (atmosphere, whether the same result happens with a dummy load that doesn't generate the microwaves, etc.), but as of writing this, we have no direct evidence that it scales to useful sizes.
There's no place I could be, since I've found Serenity...
That is pretty close to what is going on.
There are now several experiments which confirm the production of thrust, many efforts to falsify the results, and a few efforts to come up with a theory which explains what we are seeing. There may be another test or two on the ground, but the first real space trial is likely coming soon. The only real way to be sure is to launch one and measure the dv.
I had the same thought they did initially, which is that convection of air was responsible for their thrust. That will not happen in vacuum, so that idea is right out.
This is a very promising experimental result, following several other very promising experimental results from different labs. I would say there is now serious evidence that this works, or at least that there is more to it than we can easily explain given our current understanding of physics.
I'm a signature virus. Please copy me to your signature so I can replicate.
Difference:
Pons and Fleischmann announce, others try to reproduce, fail.
vs.
British engineer announces, China tries to reproduce and succeeds, NASA tries to reproduce and succeeds. Supposedly BAE Systems, EADS Astrium, Siemens and the IEE have also gotten positive results.
Of course, there is still a lot of work to be done to see if it isn't some other effect contaminating the data.
While there's still obviously (a lot more) testing to be done, it's hilarious how far people who identify as scientifically minded have gone to dismiss this out of hand.
At no point does scientific principle advocate dismissing repeatably testable results merely because it can't be explained by current understanding.
The unexplained is the epitome of everything that makes science exciting and relevant. It is precisely why science is so important.
I loved the quote from the show "Heroes" by the character Mohinder Suresh: "The default position of science is one of skepticism."
On the actual surface of Alpha Centauri? Probably not.
I think it would be nice to create a test rig, send it up to the ISS in the next supply haul, and let them try it from orbit.
To me, that would an excellent way to test if the propulsion is real, or is just another 'cold fusion.'
Uh, Linux geek since 1999.
No one would ask you to since you have no experience in the field...
Their measured force is far greater than radiation pressure could explain (around 1 newton /kW now, expected to be 500-1000 newtons per kW with some refinement if their current theories are correct), and it was not tested in sunlight as far as I know.
It cannot be simple radiation pressure, of this NASA is certain.
I'm a signature virus. Please copy me to your signature so I can replicate.
Stop being willfully moronic.
NOTHING is known to be IMPOSSIBLE. It is fundamentally impossible to prove something is impossible.
What we have reported here is an interesting experimental result that is being tested as it should be.
It is too soon to cry "Eureka!" but also too soon to be pontificating as if you have a clue about this which you quite obviously don't.
You've basically just described taping a magnet to a pole and suspending it in front of your car in order to make it go forwards, only in a slightly more complex way such that it's hard to see that's what's being proposed.
You seem to be forgetting that accelerating the particle towards A produces a backwards force. By the same token, diverting it sideways doesn't cancel out whatever backwards momentum it still contains, nor does hitting other particles to slow down (they hit other particles in turn and eventually transfer all the way to the back).
it appears to violate conventional physics and the law of conservation of momentum;
No, it does not, otherwise it would not work..
While something appearing to violate conventional physics is damned good reason to be skeptical, it isn't proof that it was a mirage. We've falsified conventional physics many times in history and upgraded physics thereby.
Violate is the wrong word, it is a better indicator that our current explanation of what is happening and how things work is not entirely correct or accurate as we think it is. Skeptical is a good thing to be. This is what makes science better than religion, because the scientific method, properly wielded, has a built in error correcting mechanism called peer-review.
If I remember correctly they oriented the first one (in atmosphere) in several different directions during the test in order to rule this out.
I'm a signature virus. Please copy me to your signature so I can replicate.
Given some of the responses to my above statement I totally agree.
And just to prove I am the bigger Simian:
I apologise unreservedly to all chimps everywhere for any insult that was taken from my statements. I see the error of my ways and am happy to state that, given the evidence that has come to light, that chimps are far and away more valuable to our world than almost all the mouth breathers I have witnessed on the internet.
Live long and prosper.
No offense, but even an AP physics class could point out that this doesn't make any sense. Yes, the perpendicular (sideways) moments (instances of thrust imparted by bouncing particles) would cancel out, but the thrusts at the normal to the back plate (that is, inline) would also cancel out. The inline component of the thrust has to exactly equal the inline-but-opposite component of the thrust caused by the bounce. You don't get to start out the set of all emitted photons with a net velocity in one direction.
If you think about it in terms of where the particles end up, it's pretty obvious this doesn't work: if there's always more thrust on the front side of the chamber (towards the thruster) than on the back, then that means the photons would all end up at the back of the chamber. For that to happen, the back of the chamber must have absorbed their perpendicular components towards itself, or the particles would have bounced back to the front of the chamber. But that would produce a thrust pushing the back plate away, which (since it's attached to the whole assembly) would counter the forward thrust.
Also, your idea just flat-out doesn't make sense: the sloped section is the forward part of the thruster (the cone points in the direction of travel). The back plate perpendicular to the direction of thrust. By what you're saying, the full component of the particle's bounce-imparted momentum would be acting *against* forward thrust, while only part of the thrust in the other direction would. The net thrust would be opposite the observed direction.
There's no place I could be, since I've found Serenity...
... Next idea was to take a bunch of one-way mirrors, and make a box of them to trap light.
This actually works but there needs to be cat inside the box.
Fifty years of Yippie! 1968-2018
"They" are many different people here. The experiment has been reproduced by, what, five different teams all across the world by now? As I understand, only the guy with the original idea is making outlandish claims; everyone else is just trying to figure out what the hell is going on.
One observation that the other teams did make is that the observed output seems to be scaling nonlinearly with input, which implies that there's a peak of efficiency. They have a model that tries to guess what that is, which seems to be consistent with the results to date. If that model is right, the peak efficiency is very high - high enough for practical uses not just in space. That is speculation, of course, but it's strictly fact-driven (and comes with a very big "if" - if the engine actually works by itself).
The rest of it is the usual journalist pop sci.
Things are so much easier now that scientists invented magic!
The "intended environment" is not necessarily space. If it produces thrust (which it does, since that's what they are measuring), it doesn't matter where it does that, it's still useful work that can be tapped.
The acceleration graph is definitely not linear. They have tried to model the relation so far, and if it holds, then it will peak at about 1 newton per watt, which is insane if it really works that way - forget ion thrusters, we could throw away the car engines!
As long as you don't change power input, acceleration is always linear.
I assume the question was rather whether acceleration (i.e. force) scales linearly with power input. In the experiment, it did not.
this gem ... hidden in the article:
"... whether it is possible for a spacecraft traveling at conventional speeds to achieve effective superluminal speed by contracting space in front of it and expanding space behind it. ..."
They've been playing at that for a while. It would allegedly work by creating a condition of cosmic expansion behind the craft and its converse in front of it, so the spacecraft is in a bubble where it's running slower than lightspeed (i.e. stopped) but the cosmic expansion and contraction regions behind and ahead of it each total to the opposite sides retreating or advancing faster than light (which is allowable).
I'm not holding my breath waiting for that to fall out of this - or anything. Effective superluminal translates to "Sending messaages into the past." and "Violating causality." if you pick your reference frames correctly. So I expect flies to appear in this ointment at some point: Like something broken about what happens at the sides, needing big-bang energy levels (and not being able to transfer them between the front and back so they're free), or not being able to set up the condition in front because the agency making it happen must involve actual superluminal signal propagation.
Nevertheless, an "electric motor" that works by pushing against virtual particle-antiparticle pairs (or the total mass of the matter in the universe, or of an inverse-square weighting-by-distance of it so it's mostly the local stuff, or dark matter, or the neutrino background, or whatever), instead of ejected exhaust, is just DANDY! Let's see if they can make it work for real at human-palpable, nontrivial, efficiencies and power levels.
I always wondered if that is how we could be able to go from subliminal.. to super luminal speeds in a fraction of a second while on the ship.. I can be sitting there in a chair and not spill my coffee. I think that might be Star Trek Physics.
A theoretical physicist, an applied physicist, and an engineer walk into a bar.
The engineer says, "Thanks barkeep, may I have another?"
The bartender bets the three that he can serve them beer at FTL speeds.
The theoretical physicist says, "Preposterous! That would violate all sorts of fundamental laws including causality!"
The applied physicist says, "If it works, it doesn't matter what your theory says!"
Consider, for example, the momentum from a photon. We can clearly generate photons through, say, an LED, emit them, and increase momentum of one object without a violation of the conservation of momentum. The thing is that we don't think that energy has momentum
Of course energy has momentum. Photons, in particular, have momentum. That's why there's nothing strange about the experiment as you describe it - you increase the momentum of your rocket, but that increase is exactly counterbalanced by the momentum of the emitted photon. And when that photon hits something eventually, it will transmit its momentum to that thing etc. Overall, momentum is conserved, not just "right now", but at any future point. This doesn't seem to be the case with this engine.
I agree. Some advanced high school physics can explain more.
There is a 3rd option here. That is of force vectors. e.g. repulsion between a number of fixed coils @ 45 degrees to each other in the shape of a cone, causes a magnetic field. The simple vector calculation would show that the field is pushed outward, away from the coils like the shape of a rocket exhaust.
What if you replace the coils with a cone* of electrons? As the repulsive force between parallel streams of electrons is enormous yet shaped as a cone, the repulsive force pushes the electrons away from the center of the cone, outside the cone itself. Again, it is easy to visualize the vectors here. A CRT only uses a single stream of electrons. Add another stream and the resultant force between them will push them away from each other. Nothing remarkable here.
But what if you contain the electrons with an external magnetic field, pushing the repulsive force back toward the center?
You will have force acting on nothing. No law was broken. The electrons are contained, moving from the apex of the cone to its base. The repulsive force is directed out of the base. There are no particles emitted, just force.
There's no magic in this. If you think about it, this force vector engine can have quite a few applications.
*The cone is actually a funnel within a funnel, sealed at the apex and base. The electron streams are in a vacuum between the walls of the funnels, moving from apex to base.
Don't be apathetic. Procrastinate!
A few physicists have already ripped it apart (and the fact that the physics is unsound is why it took so long for anyone to actually try to properly reproduce it). Basically, the thing may well work, but if it does work, it's very unlikely that the explanation that its inventor has provided is legitimate.
Several labs have detected the effect, now NASA has shown it happens in a vacuum.
Theorists must be scrambling to make sense of it.
Here's a paper that uses something called Modified inertia by a Hubble-scale Casimir effect. (MiHsC)
http://www.ptep-online.com/ind...
Note that this is the fifth experiment so far that has reproduced the effect (and every new experiment tries to account for some explanation that could possibly invalidate the previous one; e.g. for the last one, they ran it in vacuum).
Are you saying that you would completely ignore the repeatedly reproducible result of an experiment if there were no good theoretical physical explanation for said result?
I mean, it's your choice, but it sounds extremely stupid. If the thing works, figuring out why it works is definitely a very interesting question well worth devoting resources to, but making it useful doesn't require fully understanding the theory.
Wrong.
Conservation of linear momentum is most certainly NOT derived from Thermodynamics.
Conservation of linear momentum is a mathematical consequence of translational symmetry - in other words, momentum is conserved if the laws of physics are invariant in space. Similarly, angular momentum is conserved if the laws of physics are invariant by rotation.
You forger that when a particle changes its heading due to an EM field, the particle only affects the EM field locally and not the EM field generator. Hence there is no magnet on a pole (no Munchausen pulling himself out of the mire). It is not a perpetum mobile as energy is constantly being brought into the system by the EM field generator power supply.
First of all, you need to be careful of your pronouns. "They" the inventor of the device is mostly just saying it can be used to replace satellite thrusters, which would be a huge weight saving (no need for maneuvering or stationkeeping fuel). "They" NASA are saying that, *if* it scales up the way their current model says (yes, they have one), then after a lot of refinement and with a nuclear reactor powering it, this thing could produce hundreds of Newtons of thrust at a scale that would be feasible for spacecraft propulsion. Some people have worked out, based on the predicted thrust and the likely mass of such a craft generating that thrust, that it can be used to reach Alpha Centauri in under a century. The first of these is an obvious use case for anything that can generate a tiny thrust for a long time. The second is a straightforward application of the current-best (though probably still in need of major refinement) model of thrust detected to power input, which has been measured. The model is a guess, but the fact that more power = more thrust has been demonstrated; it is, as you say, a concrete fact. The third thing - the starship drive - is simply once again a straightforward application of the results of the model. Nobody is saying that the EmDrive makes starships possible, just that if we *had* a starship, and if it was propelled by an EmDrive that corresponds to the current model of power output, then it could reach Alpha Centauri in N years. That's simple mathematics; you can do the same for chemical rockets or solar sails or any other form of propulsion that works in vacuum.
Second, I don't know why you're calling the idea of scaling up an observed result "delusional". The first Wright Flyer could barely get one person off the ground for a few seconds, flew slower than a horse could run, and was so fragile that it was shattered by a gust of wind after only four flights. But, once you've demonstrated that it *works* - that heavier-than-air flight is actually possible (which should have been obvious to everybody, given that birds and bats and insects exist, but plenty of people thought humans would never achieve it) - then scaling that up to WW2 bombers was pretty straightforward: more-powerful-for-their-weight engines (the Wright brothers had to design their own engine; the existing ones at the time didn't have enough power to weight ratio), stronger-for-their-weight materials, lots of refinements to the design (the Wright brothers pioneered the use of wind tunnels and used them to fix several significant errors in the equations that govern aspects of flight like lift, but their first Flyer was still a very primitive design with many compromises or outright flaws), and other simple, iterative improvements. Breaking the sound barrier was a bigger challenge than getting across the ocean in one flight, in terms of theoretical challenges. All this from a craft that could barely get one guy a few hundred feet down a beach.
If somebody had watched the Wright Flyer and said "one day, people will be able to fly to Europe from the US in less than a day" would you have called them "totally delusional" too?
There's no place I could be, since I've found Serenity...
Just put a small version of this thing on some spacecraft/satellite (ISS, Progress, Dragon, etc) and run it for a while, if it works the satellite should show some noticeable change in its orbit if it doesn't its garbage. Unfortunately the supposed thrust of this thing is so miniscule that it is the only way we're going to get definitive proof that there is an actual thrust from this thing.
I get that this is Slashdot and almost nobody reads TFAs, but seriously, the last time this thing was discussed there were plenty of comments pointing out that it had already been replicated in three different labs around the world... *last year*! True, I don't know if the "... in a vacuum" result has been replicated yet (though at least one lab has offered to do so) but considering that the results in the vacuum were consistent with the atmospheric results (and also considering the care that was taken to ensure that the result wasn't being caused by the atmosphere anyhow, like comparing the operational device with a dummy load that still generates the same heat, or turning the device around) I don't think that the error in our expectations is due to vacuum-vs.-atmosphere, so the other experiments are useful examples of the same effect.
There's no place I could be, since I've found Serenity...
There are a number of reactionless drive proposals, not all of them unreasonable:
http://en.wikipedia.org/wiki/R...
Given that space is far from empty (vacuum fluctuations, dark matter, dark energy), the traditional view of reactionless drives is also not entirely supported, since in non-empty media, you can "swim" in one form or another. So, you may not only be able to "swim" against spacetime (see the link), but also against these other backgrounds.
Of course, anything that ejects photos can also be used for propulsion (photon rocket), and you can eject photons even from an antenna, so in principle, even a wire with an oscillator can generate some thrust which looks reactionless.
This experiment doesn't contradict any theory, it only contradicts the Platonic ideal of the vacuum and flat spacetime that Einstein used in the Theory of Relativity. In the real world, all we can say is that there is no good explanation how this setup could generate this amount of force.
Most likely, it's an experimental error, and few people are willing to waste much time on such out-there experiments. But it's good that some people are daring and check up on this stuff.
The more reproductions without someone figuring out what's wrong with the test the more likely it is that it's not the test that's wrong.
This engine is interesting on many fronts, the most important of which is it appears to violate what we know about conservation of momentum and IF it does it's going to actually point to some fundamental constant or principle of the universe that we've missed as long as it's not an experimental error. This is a big hurdle to take so it's going to take a LOT of evidence there is no mistakes with the test or engine.
Could be pretty cool if it turns out real. We won't need to ever worry about fuel for satellites and all you would need to travel to mars or even Pluto or even another star would be an energy source that would last the length of the journey. I wouldn't be surprised to see the DOD put one of these into space ASAP to find out if the work, it would revolutionize spy satellites if they don't have to worry about propulsion fuel.
If it works, then the explanation the inventor provided is irrelevant. Someone else will come up with a better explanation. I doubt anyone would say, "we shouldn't continue testing this EM engine thingy because we don't know why it works."
Sometimes, it's better to be lucky than good, you know?
You are welcome on my lawn.
It is very hard to believe that they are going to send a propulsion system into space without a clear understanding of how it works. They claim that they have a device that violates very basic physics. They shouldn't be thinking about space flight at all. They should be asking the best experimentalists in RF cavities to collaborate with them to win the Nobel prize that will be given to anyone who shows a human scale object that violates the known laws of physics. It would be easily the most important discovery of the last 50 years. But for that same reason, it is 99.9% likely to be a misinterpretation of their experimental results.
Yes, of course. I don't support this ridiculous notion that we shouldn't try to get something useful out of the experiment just because we can't explain the theory.
I can attest that it is not thermal. It works in a vacuum. It works in a Faraday cage and it works when you reverse the device (the thrust reverses).
The fact that the anomalous readings are net thrust is pretty encouraging.
Launching things into space is expensive, devices intended for space are harder to design, and it makes the experiment harder to run and measure. Better to run some tests on the ground first, produce a model on which they can base a more efficient design, test that design in order to maximize the thrust they can easily get, then go design an actual test spacecraft (which will probably be tiny, and take some time to do.)
A series of promising results on the ground are a good sign, and are what make it worthy of the further work and expense necessary to test it in the intended environment. I am sure someone will get around to launching a test vehicle in due time if nobody comes up with a better explanation for the results than generation of thrust.
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This isn't junk science. This is junk sensationalized journalism reporting about science. Rest assured that if any agency capable of orbital launches was actually confident in the merits of this device, it would be in orbit within the month.
Most of those are governments... Maybe you are hoping SpaceX will make this a priority as a non income generating research project? If not, I think there is an important life lesson about the speed at which government agencies and their contractors accomplish tasks in your future.
With five years is more likely, assuming a better explanation which makes it useless as propulsion is not found. Maybe within a year if it gets the attention of those who create the budget.
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I don't care about hearing anything. I want to throw the damn thing up into space and see if we get delta-v. Then we can hypothesize whether we heard anything and if so what the hell animal it was. Given the apparent reproducibility of something so profoundly game changing surely we're at a point to merit putting this thing on orbit to finally decide if we have something here.
Two of my imaginary friends reproduced once
The experiment being discussed was done at a NASA lab by NASA people.
Actually, I would describe the US Navy as being pretty crackpot heavy. ONR houses a rather.. ahm.. special.. community of researchers who go down all sorts of off the wall paths.
I really need one of those for my car ASAP.
Sounds like you need some Flubber?
Well in that case, I've got plenty of Comcast bills to donate. They just need to be paid in full.
Life is not for the lazy.
Which is very good but the yelping of "four days to Mars" distracts a lot from something that may have implications or may not. I know you are not doing the yelping, but there's enough of it about to obscure the issue and have anyone who asks "I wonder what is really going on in that machine" yelled down as a luddite.
In a few years there may be an opportunity to put something like this above the atmosphere and see what happens.
NASA had a manager forced on them who was most definitely a crackpot, but aside from that crackpot ideas do occasionally turn up in respectable places.
Back when I was working in a University mechanical engineering department we had one of those massive fuel saving engine nuts, who was also a famous artist, turn up with his modified car engine that was tuned to idle instead of running under load. Sure enough, it didn't use much fuel, but that's because the power output was buggerall and you couldn't use it for anything. The artist was very paranoid that we would steal his useless work but we managed to work out what he'd done just the same and we had to break it to him gently that it wouldn't have been interesting news in 1880.
So whether this is the next big thing or just something weird just having it tested by NASA is no sign of validity, it's what NASA say about it that matters. At the moment they are still saying it's something weird. That could go somewhere, but not "four days to Mars" as yet.
It took me years before I came to the conclusion that I have no clue how high temp super conductivity works. We've got some ideas that match what happens in one material and then another material that couldn't possibly conduct with that theory goes and does it. I'm no expert but I've been following it for a few decades and made up and examined some of the cheaper to fabricate materials.
Within the realm of laws of physics that people are really, really sure of, it's impossible. Don't be wilfully moronic. This means it's going to take a lot of convincing, and it almost certainly isn't a real effect, but it's going to be a real big thing if it is.
"When you have eliminated the unacceptable, whatever is left, however improbable, must be the truthiness" - Holmes
We already know about photon thrust. As a practical matter, it sucks as a space drive, since the amount of momentum we get from a given amount of energy is pitiful. This engine is claimed to produce a lot more thrust than a photon engine, which means it isn't just transferring momentum to photons.
Are you talking about virtual particle pairs? Where does the momentum go when they vanish? Bear in mind that they appear and vanish faster than we can directly notice them, so how is momentum transferred, and how is it conserved over, say, a millisecond?
"When you have eliminated the unacceptable, whatever is left, however improbable, must be the truthiness" - Holmes
Unless you're like me and purposely ignore such garbage. AND YOU WON'T BELIEVE WHAT HAPPENS NEXT!
Unless it's Clarkeian magic. Then you need a sufficiently advanced scientist to explain it.
There are several medications doctors prescribe although they and even the researchers that invented them don't how or why they work.
obligatory, something something land at night.
To me, she has 2 vaginas and 1 tit
Table-ized A.I.
Its not easy to measure 50 micro-newtons of force when you change a power level by 50 watts.
Currents cause magnetic forces. Things get hot and outgas producing thrust. RF power cables get hot and distort causing a force.
Think about it. The device weighs something like 5Kilos. That is 50 newtons gravitational force. So a 1 micro-radian tilt will cause a 50 micro-newton force. Walking across the lab floor could cause that amount of deflection. If the chamber is 1 meter across, a 0.1 degree temperature change on one side of the chamber (from a nearby power supply) could cause that much tilt.
There of course could be force just from photons - but that is a simple and well understood photon drive - known for at least 50 years now - basically a light-sail.
This is a very difficult experiment to do correctly, and they have not published in enough detail.
Meanwhile: conservation of momentum has been tested under conditions ranging from ultra-cold gas atoms to 100GeV particle collisions, to orbiting neutron stars. The RF fields they use are very modest. At SLAC we run hundreds of megawatts, not 50 watts. We have superconducting cavities where we easily see the deflection caused by the momentum in the microwave fields - operating at many thousands of times higher power than this experiment - we see nothing unexpected.
So: Difficult experiment. No unusual physical conditions. Apparent violation of one of the most carefully tested conservation laws in all of science.
It it literally more likely that the sun will not rise tomorrow (since that is also based on conservation of momentum) than that this experiment was correct.
Woosh....
There are a number of concepts for accelerator driven nuclear reactors. Nothing fundamentally crazy, just none have been made practical yet. I don't know if there is enough room to increase the efficiency of generating and collecting neutrons - it may be that you just can't quite get there. Similar situation to muon catalyzed fusion. It *almost* works, but the muons stick to the helium after it is formed and you can't quite come up with a scheme where it is a net energy producer.
Theses sorts of concepts are being looked at - they may eventually get one to be practical, but so far no.
If you use energy to create real particles out of virtual ones, you are building something very like a photon drive. Its just like an LED converting electricity to matter (photons). Those photons produce thrust - but the thrust / power is extremely tiny. This limit applies to any sort of particles you might produce.
Or it's managing to accelerate something on the opposite direction. It's clearly not air. Perhaps it's this "dark energy" or "dark matter" that doesn't get half the skepticism here even with sparse evidence. Or perhaps it actually is virtual particles. Would it really be all that shocking that there's something about the quantum foam that we don't know yet?
It could be that there is a more conventional explanation. Perhaps not. But stomping and saying impossible won't get us anywhere. Nor will throwing out unsupported theories as if they were established fact. That's not science at all.
Personally, I'd like for the next run to measure electrostatic and magnetic effects though honestly, I doubt that would explain it.
I have spent my life (or at least 35 years) studying physics and doing experiments, many of which include high power microwaves.
There are a lot of ways for them to have gotten this wrong, and it violates very fundamental physics principals. They can publish in a refereed journal with enough details to satisfy other physicists if they really have something.
It is very hard to believe that they are going to send a propulsion system into space without a clear understanding of how it works.
We send drivers on the road every day who don't have a clear idea how cars work.
Knowing how something works is nice, but not knowing how it works won't diminish its utility, so long as it *does*.
We use gravity daily to generate hydroelectric power. Ask a group of physicists how gravity works. We have the math for it, but we don't have the story of it. Either way, the lights come on when the water weight is converted from potential to kinetic energy, and we are still damned if we know the mechanism of conversion. If we did, we'd al be riding around on hoverboards.
I think that the people who are actually doing the real work here (i.e. the scientists) all have fairly realistic expectations. The rest of us can party if it makes us feel better, and it won't hurt if the end result is increased funding for science in general. And if nothing happens in the end, well, there won't be any more articles, and in a month everyone except for those genuinely interested will forget it was even there (well, there will also be the occasional science freak posting about it on Slashdot in every future story on space propulsion, but that's what Slashdot is for).
WHAT'S IN THE BOX!?!?!?
Not logged in I saw a post by someone about Flubber. Can't easily find it (or log in) using an iPhone so here I am.
im a pretty firm believer that gravity has a lot to do with everything. Action over a distance is poop. There's something underneath the vacuum -- we are all just jiggles of whatever that is, and space is just a little less jiggly.
If someone is pulling energy from nowhere, it's likely scooting in nearly undetectable across the aether.
Conservation of linear momentum is a mathematical consequence of translational symmetry - in other words, momentum is conserved if the laws of physics are invariant in space. Similarly, angular momentum is conserved if the laws of physics are invariant by rotation.
And energy is conserved if the system is invariant over a translation in time.
Hooray for Emmy Noether.
If it weren't for deadlines, nothing would be late.
Dude. White did the best he could with the money he had. Not everyone has the facilities to conduct those kinds of tests.
However excessive hype leads to "fatigue" and we end up with the "don't tell me about it until I can buy it at Walmart" attitude creeping into even places like this.
Good on you for mentioning that. The correspondence between symmetry and conservation laws has always been one of my favorite takeaways from the undergrad years. Good stuff that.
Your logic is sound for an eight year old. More mature logic has to deal with the fact that the drive does appear to work.
Try looking up Casimir-Polder force on wikipedia, for another example of quantum level physics producing classical level forces. Oh, I just did that for you.
While in a classical sense these phenomena appear to involve breakage in conservation of momentum, that apparent loss of momentum might well be explained through some aspect of quantum foam behavior. Can energy waves be transferred through quantum foam? Why would that not act like any other medium?
I'm guessing that as we learn more about manipulating quantum events like this drive and Casimir plates, we will get a better understanding of dark energy. But what do I know. I'm much more into woo-woo metaphysics than classical physics or quantum mechanics.
Will
Or just being unable to find a way to have negative energy density in a volume of space required for expansion of the universe (unless there are other ways to expand spacetime, but as far as I know, the quantum physicists haven't yet found a way to replace the Einstein Tensor)... Maybe we'll get our hands on some condensed dark energy ;)
OK, I will try to restate in my baby talk since I don't remember this correctly.
Given that you are accelerating, the appearance to you is that you are doing so linearly, and time dilation is happening to you. It could appear to you that you reach your destination in a very short time, much shorter than light would allow. To the outside observer, however, time passes at a different rate and you never achieve light speed.
Bruce Perens.
It is the same as if you are locked in a cage and bump yourself against the wall - the cage eventually moves. yet nothing is expelled outside of the cage.
No- it is *not* like that.
This is like you throwing yourself against the wall, and it reacting with the force of a Saturn V.
You are still talking shit...and being very small minded.
This is a verified experimental result.
It needs further investigation and is an exciting result.
All your jibber jabber does not change this fact or my previous one.
Have none of you read Three Body Problem??? No spoilers in my post, but the answer is out there... (Yes, I'm going for funny)
Seriously, though that book is awesome and should win the Nebula this year. If you like hard SF you need to read it right now.
...we can violate conservation of momentum by invoking some sort of vaguely defined quantum woo
As far as I can see, Roger Shawyer is not a wild-eyed madman, but a serious engineer, who argues his case soberly. That is not to say that his claims are correct, but simply means that he actually offers something that is worth scientific scrutiny and which can be discussed and tested. On the other hand, since this is not all over the new channels, it is not something that has been demonstrated unambiguously enough yet; if this was definitely proven, then we would hear about it even in the general press.
There are two wikipedia articles:
http://en.wikipedia.org/wiki/E...
http://en.wikipedia.org/wiki/Q...
- that seem relatively trustworthy. To me it looks like a slightly speculative concept, but one that could well have some theoretical support; I am not an expert in QM, but to my eyes it looks somewhat plausible. He doesn't claim to violate fundamental laws of physics - if he is right, and this drive works, then it uses the same phenomenon that lies behind the Casimir effect (well, read the articles, really). It doesn't generate energy from nothing, energy is expended in the process; and it doesn't work like a rocket, it seems, but like a paddle steamer, in that it sort of crawls along in the soup of quantum fluctuations (yes, I don't know what actually means either, but it sounds cool, and apparently it is an observed phenomenon, ie. real).
Which "they" are you talking about? The linked article *does* give an "answer" - "the Quantum Vacuum (the quantum state with the lowest possible energy) behaving like propellant ions behave in a MagnetoHydroDynamics drive".
It also claims that a model based on this theory is being used to guide the NASA team's experimental design. To be fair, that's not necessarily unreasonable, in the absence of a more credible theory.
It is too soon to cry "Eureka!"
Did you read the article? Sounded pretty much like "Eureka!" to me.
I think that if this is valid, the correct theory will follow soon enough anyway, but in principle, why must we know how something works before letting it benefit humanity? Did the early caveman have a deep understanding of fire when they were roasting their woolly mammoth cuisine?
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Just as well the EM drive still requires a source of energy then. What I'd like to know though is where the energy is going to. Is it just bouncing around inside the cavity and heating it up as a result?
Why OpalCalc is the best Windows calc
I am sure they will experiment with a few prototypes and come up with a model of how it works before they launch it.
You want an explanation as to why it either fits with our current understanding of physics or where our understanding was wrong, which is not required in order to make use of it. From an engineering perspective all we need to know is how much thrust it produces, if there are any side effects that could cause problems, and how to keep it functioning.
We can do all of that through trial and error and some basic modeling, without understanding exactly what is happening.
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The EM drive is controversial because it was never shown to work in proper test condition (at rest - starting up by powering it) and excuse are being made up for why it needs to be in motion to be tested , a fact make it magnitude more harder to test if there is ANY effect whatsoever.
C. Sagan : A demon haunted world:
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visit randi.org
I've seen plenty of work on accelerator-drive heavy isotope reactors but nothing for light isotope reactors like lithium. Accelerator driven heavy isotope reactors still deal with many of the problems of conventional fission reactors - they're greatly improved in many regards, but still problematic (you still have some plutonium, you still have some fuel availability/cost limitations, you still have some long-lived waste, you still have some harder to shield radiation, you still have a wide range of daughter products making corrosion control more challenging, etc - just not to the degree of a regular fission reactor). A light isotope reactor using lithium would virtually eliminate all of these problems. And it has a higher burnup ratio, which is of course critical for space uses.
And while everything I've seen about past improvements in accelerator efficiencies and spallation process improvements, and what's being worked on now, suggests no limit any time soon on neutron production efficiencies - at least that's how it looks from the papers I've read. Plus, even if efficiencies couldn't be improved any further (there's not that much further one needs to go), one could hybridize a heavy isotope and light isotope reactor, using a heavy isotope target as a neutron multiplier to bombard the lithium. You'd require significantly reduced quantities of heavy isotopes relative to a pure heavy isotope reactor, and most of the energy from the lithium side could be as mentioned captured without Carnot losses, which is a big bonus. Any non-thermalized neutrons of sufficient energy would produce tritium as a byproduct, which of course would be a value-added product - in fact, given that the tritium-breeding reaction with 7Li and a high energy neutron yields a lower-energy neutron, the thermalization could potentially be done via tritium breeding in the first place. And tritium is a valuable product whether one has interest in D-T fusion or not.
I just think it's weird that I've not come across any work on a lithium-based accelerator-driven spallation reactor, and was just wondering if there's a reason for that. It certainly looks appealing to my non-expert eyes. I mean, it looks even cleaner and more fuel-available than D-T fusion, and looks closer to being viable on a full-system perspective. Versus accelerator-driven heavy isotope fission you get less power per neutron (about a quarter as much), of course, even accounting for Carnot losses in the former - but that's not what matters. Cost is what matters, and if you're eliminating the use of super-expensive fuel, not producing any costly-to-manage waste, have no incident radiation, no proliferation concerns, etc, you're completely changing the cost picture - without even considering the possible joint production of saleable tritium.
Sigur RÃs: I didn't know that Heaven had a rock band.
just having it tested by NASA is no sign of validity :D
Of course it is not.
However when I have to bet on either the NASA or on a basement couch potato, I rather take NASA
Cost free eBook I read (by iBook/Kobo/Amazon/ObookO/Gutenberg etc.): "The Green Odyssey" by Philip Jose Farmer.
It stands to reason: Fairies flying out of the engineer's butt would more likely apply 50 micro-newtons of force to the engineer, not the experiment.
You are in a maze of twisty little passages, all alike.
Has anyone ever taken Randi up on his challenge? Or are they all chicken?
I enjoy his contributions to the field of skepticism, along with his fan Brian Dunning from skeptoid.com.
You are in a maze of twisty little passages, all alike.
The two sources of experimental error that first occur to me are interference with the signal conditioning for the load cell and the Lorentz force.
Electrodynamic propulsion works but conservation of momentum still applies.
http://en.wikipedia.org/wiki/E...
It creates a "Virtual quantum burrito"? As long as there's a burrito in the microwave, thrust is always guaranteed to be generated!
I'm trying to teach myself to set people on fire with my mind... Is it hot in here?
That's pretty much what they're doing. NASA has been pretty quiet about the whole thing. The results have mainly been presented at conferences.
It's an extraordinary claim, but it does seem like they're working to provide extraordinary evidence. Also, the thrust claims aren't really very subtle. 1 N is pretty easy to measure, and the Chinese say they can get that using only 1 kW. It sounds like you could build one of these with a decent metal shop and a household microwave.
The article talks about a model made by the NASA group assuming acceleration of virtual particles. It suggests greater than linear thrust to power ratios with increasing power, up to an optimum. Presumably the details would also depend on the type of device, frequency of microwave, etc.
Possibly momentum imparted to virtual particles can be transmitted through the EM quantum field, eventually being imparted to any real matter along the way.
They're measuring an anomalous force in an electromagnetic cavity. That's a measurement, a concrete fact. They're claiming that they'll be able to make a starship with it. That's beyond any credibility. It's totally delusional.
Jesus H you're dishonest. They HOPE to use it to propel objects from LEO to GEO. The reason that NASA is looking into this is in the HOPE that it bears fruit. NOBODY said they WILL be able to make a starship with it.
Some of the statements get rather ambitious, but they aren't statements of fact they're suggestions about what COULD be possible if this pans out.
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There are still a lot of ways for the experiment to get the wrong result in vacuum. The force is really quite tiny.
Their "hard" vacuum was 1e-6 torr scale. That might still be enough to to produce some force. There can be effects from temperature causing anomolus forces in the suspension mechanism. There can be magnetic field effects from power cables. Torque from RF cables getting warm.
This would be a very difficult experiment to do correctly. Without details, it is much more likely that they got it wrong, than that they have found a violation of conservation of momentum.
As an aside, quantum mechanics still conserves energy and momentum. The pushing on virtual particles from the vacuum doesn't work unless you add enough energy to turn them into real particles - and then you just have a photon drive variant (which would produce far less thrust).
All observed phenomena obey the laws of physics. By definition.
Bullshit. All correctly observed phenomena obey the laws of physics. Funny thing is that the vast majority of observations that apparently violate the laws of physics turn out to be incorrect.
The current case is a good example. NASA used 100 watts and measured a force of 50 microNewtons. You would need a force 20,000 times larger than that to levitate an apple. Unless you increase the efficiency of the effect by many orders of magnitude then, even if it exists at all, it has no practical application.
In these sorts of situations where experimentalists measure a very very small effect (the measurement made in China, which was not in a vacuum, was over 100 times larger) and there is no reasonable theoretical explanation for the effect and the effect contradicts the established laws of physics then the explanation is almost always experimental error.
We don't see the world as it is, we see it as we are.
-- Anais Nin
First let me grant that this is obviously worthy of more study due to all of the experimental confirmations. However... you can't go through life saying "hmm, interesting" to every weird claim everyone makes. For example, if you listen to a moon hoaxer or 9/11 truther you will very quickly hear something that is either:
1. Complete nonsense, delusions and/or lies
2. A gross distortion of the actual facts
3. A somewhat interesting and entirely truthful claim about reality, but one that has a much simpler explanation than the one the nutjob is putting forth.
4. (not yet seen this one) an unexplained phenomenon
5. (not yet seen anything remotely resembling this one) Proof that explains away the evidence that appears to support conventional wisdom and supports the nutjob's theory instead.
You literally can spend your entire life examining the claims made by these nutjobs--just these two specific types of nutjobs (nevermind the homeopaths and miracle workers and such.) You occasionally run into item #3, which is cool but doesn't significantly add to our understanding of the world. It's not reasonable to chastise us that we must keep digging, we must stay perfectly neutral and agnostic because of the possibility of #4 or #5. The world is utterly teeming with nutjobs and cynical snake oil salesmen. The burden of proof must remain on those with the extraordinary claims, even if us skeptics do not have a ready alternative explanation.
One main issue here is the nutty behavior and statements of the original inventors). This is somewhat alleviated by experimental replication, but the other outstanding issue is, as others (and XKCD) have noted is the very low efficiency. If you pump a large amount of power into something and there is a small unexplained movement, the natural assumption is there is some unnoticed flaw in the system that is somehow allowing the apparatus to turn a small portion of that energy into physical motion through conventional, well-understood physical laws. It's a mystery, sure. But it's not one that automatically demands huge amounts of our attention and money.
Somebody please +1 this guy informative. This was a perfect, simple explanation after a sea of gobbledygook
Every rule has more than one consequence.
5 citations required. Note that they have not been published and have all have large issues with experimental procedures.
If information wants to be free, why does my internet connection cost so much?
Which was my point. The Italian scam (by a convicted scammer even) haven't allowed a scientific examination of the device but have allowed the scammer himself unhindered access to the device.
This is something done in a NASA lab with NASA people using a scientific methodology.
Oh and your definition of magic might also need adjusting using the same declination.
My definition of "magic" doesn't need to be adjusted. There is no such thing as magic. Just laws and principals that we do not understand at this current time. To define them as "magic" would put us on the same level as the homo erectus cowering caves as the thunder and lightning flashed in the storm.
Supporting World Peace Through Nuclear Pacification
but the simple thing is, all those 'laws of physics' are not actual facts, they are based on stuff 'we' think we know, and need to put into some laws just so we can try to understand what is going on, up to a moment when the laws don't count for something we see happening but can't understand due our self defined laws of physics... remember, the smartest people in the world also said the world was flat and if you said otherwise you were a heretic, but later we knew the world wasn't flat.........
It's one thing to be open to the possibility that something is incomplete.
It's quite another to write a long web page with grand predictions for something that is unproven and has no theoretical explanation yet.
It's also ludicrous to make a computer model without any sort of theoretical basis. I can "invent" a warp drive by imagining that $_phenomenon is a good approximation of $_supposed_operating_principle and making a computer model of that. Naturally, the results are pure bullshit and profoundly meaningless.
Neither of the above disproves very solid physics. It'll take something a lot more formal to reasonably conclude that space is asymmetric.
This is an experimental result. It means something, and it might even mean something interesting. It should be investigated further until we know what's going on.
If it is a reactionless drive, it violates some very fundamental and well-tested physics. That would be an extraordinary claim, and hence requires extraordinary evidence. I haven't seen extraordinary evidence, and am 99% sure it isn't a reactionless drive.
"When you have eliminated the unacceptable, whatever is left, however improbable, must be the truthiness" - Holmes
I asked Teller once... He was silent on the matter.
Yes it's an anecdote! Were you expecting original research in a Slashdot comment?
But NASA already has it working in their laboratorie...... And it does work.....
If they simply wrote a paper saying "we noticed an anomalous force in this experimental setup, and we don't understand why", then nobody would have a problem with it. They're not doing that. They are claiming that it can be used as a reactionless propulsion system, a claim which is entirely incredible without a solid physical theory to justify it.
Eppur si muove always trumps "all the laws of physics say." Always. No exceptions. Our understanding of the laws of physics will just have to try to catch up to the reality. That's assuming, of course, that the gizmo really does muove.
the expected thrust from 10GW of power beam is 33 Newtons
And the expected thrust from 1W is 3.3 nanonewtons. See the problem? I'll give you a hint- they measured ~1millinewton/W.
They're measuring more thrust than the photons they're generating actually have to give.
The problems of no leaking emissions, thus making this not a photon drive, or what they're theoretically pushing against (magical quantum vacuum effects at microwave photon energies) are secondary to the problem that they have magically generated more momentum than they put into the system.
We use gravity daily to generate hydroelectric power.
Really, we use the sun to generate hydroelectric power. We use the gravity and terrain to reclaim the energy the sun gave the water in a less complicated fashion ;)
Wait- really?
The system is both magnets... the sum of the momentum change is 0.
Now put 2 magnets in freefall, and get one of them to move another without moving itself, now you've recreated the EM Drive.
Alpha Centauri??? With a perpetual motion drive? To hell with that. I'll see you at the end of the Universe.
No, it won't.
They haven't even completed the first round of formal experiments. You know, the kind with scientific write-ups and peer review of experimental setup and such.
So far there have been some tiny anomalous observations that may or may not be due to a force we don't understand. They are far more likely due to a force that we understand perfectly, but have failed to take into account while making the observations.
NASA hasn't published anything definitive on this. The have (quite stupidly, IMHO) given some of their initial results to the press, who (of course) blew the story up beyond any sensible measure.
The next thing we will likely see is a better experimental setup at higher power, which will likely explain the completely conventional reasons we see these results. These will be published, and not picked up by the press (cause it's "boring"), and in a few years people will wonder "whatever happened to that EmDrive thing?" Conspiracy nuts will claim government cover-up, illuminati, stolen by bigfoot, etc.
"Something weird is going on" is not the same as "it works and we can actually do stuff with it".
The universe seems to be speeding up its expansion. Doesn't that violate every conservation law?
I think it's likely that the test is faulty, but they need to figure out why or how the test is faulty.
There is actually a better chance that curiosity, need, whatever, will continue to drive development of practical technology without science having uncovered the secrets of how it achieves its practice until long after its wide adoption. You may have heard of boat building, which our species invented here on Earth a long time ago and long, long before anyone realized what water really was and why things sink or float. NASA is one of the few organizations that justifiably has been long prided by I think everyone to be a group of ideally dedicated smart likeably cooperative over-achievers that successfully apply science rationally to develop technology to achieve the goals set before them. If you had the capital and need to do so, who would you hire to get you safely there and back if "there" was Earth's orbit or beyond? NASA's on everyone's short list. I'm interested because this is pretty good nerd news, and not any weekly world tripe, that some scientists with merit have (with transparency and established process) produced eye-popping results in an experiment and with an apparatus that does not share the secret of its result in any obvious way, IOW, wtf, that's impossible... what gives? I can't just hand-wave off that obviously one of these bozos messed up... it's NASA, they really can't afford bozos... just the regular type of professional scientists and engineers that excelled in such a way professionally to interest NASA into hiring them, and they're neither a dime a dozen nor are there very many dozens of them to begin with... considering... Merica... today... a little soft in the middle, but some of our agencies and facilities are still intact. NASA is one of them, and very much alive... everyone, everyone, should just fucking send NASA $10, you know they won't steal it, they'll actually use it to complete their mission. The first thing I'd doubt before doubting NASA was the fidelity of the information between reports and what NASA really did and said. So you can bet that somehow NASA did a faulty test, while I can bet that somehow between you me, the editer, reporter and the laws of physics something might have slid a little and a small error, in comprehension or reporting, whatever it was... a small error has turned into something now widely reported. Or maybe there is no error... something really great is happening and our best guys don't know why but they're sure the best guys we have to mess around with this and develop if it indeed is doing what they're reporting... even if it reads like a practical joke, I don't really care, its so much better news than... you know all the other crappy news... crime... war... etc...
The Admin and the Engineer
Ah, so it's like Bistromatics?