China's Radical New Space Drive 419
First time accepted submitter Noctis-Kaban writes "Scientists in China have built and tested a radical new space drive. Although the thrust it produces may not be enough to lift your mobile phone, it looks like it could radically change the satellite industry. Satellites are just the start: with superconducting components, this technology could generate the thrust to drive everything from deep space probes to flying cars. And it all started with a British engineer whose invention was ignored and ridiculed in his home country."
I'm pretty sure it doesn't work (Score:5, Interesting)
The principles behind the EmDrive have serious theoretical problems, and the original builder and designer never tested it in a vacuum chamber.
Taking a sealed container and pumping a few kilowatts of microwaves into it, chances are any thrust developed is actually air that's getting heated up and expanding out of the container. Unless the EmDrive has been put in a vacuum chamber where this can be demonstrated to definitely not be the case (i.e. low enough that their couldn't be enough reaction mass) then it's not actually working.
Devil's (angel's?) advocate: (Score:3, Informative)
That effect would not last long. If it produces continuous low thrust in atmosphere, that can't be it.
More likely, as one of the groups that looked at this observed, is that all that RF (2kw) is simply interfering with the instrumentation.
Re:Devil's (angel's?) advocate: (Score:5, Interesting)
The thrust is reported to be from the large end towards the small end. The entire body of this thing that's heating up from a few kilowatts of microwaves would be warming air that flowed over the surface and thus imparting energy to it and providing a source of thrust. It would easily provide continuous thrust.
Re:Devil's (angel's?) advocate: (Score:4, Funny)
"The thrust is reported to be from the large end towards the small end. "
No, TFA says:
"... experiences a net thrust towards the wide end."
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"The thrust is reported to be from the large end towards the small end. "
No, TFA says:
"... experiences a net thrust towards the wide end."
"Thrust towards" is ambiguous. Dig through the website on the proposed theory [emdrive.com]. The implication is the force is exerted on the large end, so the contraption moves large end first.
Which - again - is the same behavior you'd get from heating air along the length of the taper.
Stop arguing and TEST IT! (Score:3, Insightful)
Just get one of these things and test it under rigorous scientific conditions and scrutiny.
If it works, it works; If it doesn't it's back to the drawing board and we can all move on.
Al this fucking shitbrained arguing over nitpicky sematic points is just maddening. Put up or shut the fuck up, because we don't want to hear your not-based-on-anything-that-counts armchair scientist opinions.
Re:Stop arguing and TEST IT! (Score:5, Insightful)
Just get one of these things and test it under rigorous scientific conditions and scrutiny.
If it works, it works; If it doesn't it's back to the drawing board and we can all move on.
Al this fucking shitbrained arguing over nitpicky sematic points is just maddening. Put up or shut the fuck up, because we don't want to hear your not-based-on-anything-that-counts armchair scientist opinions.
"Just get one of these things"
You know who has one of these things? The people who built it. You know what evidence they can't put up? The type which discredits a very obvious criticism. One would think with that type of headstart and knowledge of its operation and experience with test setups, this type of demonstration would be an obvious one.
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Just get one of these things and test it under rigorous scientific conditions and scrutiny.
If it works, it works; If it doesn't it's back to the drawing board and we can all move on.
From TFA:
Boeing's Phantom Works, which works on various classified projects and has been involved in space research, went as far as acquiring and testing the EmDrive, but say they are no longer working with Shawyer.
So either it didn't work, or Phantom Works already has/came up with something better. On a related note, the article makes kind of a big deal about the "propellant-less" claim, even though we already have a propellant-less drive with extremely low thrust: solar sails. Although, admittedly you'd need a pretty huge sail to reach 720 mN (the claimed thrust) in Earth orbit. Actually, 720 mN is quite large compared to current ion engines, so I'm curious to know what Phantom Works found.
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... , and the original builder and designer never tested it in a vacuum chamber.
maybe try reading the context of a post before inserting the snark next time?
Mach-Woodward Effect (Score:3, Informative)
Well, that's what people have said about the Mach-Woodward experiments, but an opposed piston design is now being tried out to isolate any noise-producing effects for remediation:
http://arxiv.org/abs/1301.6178 [arxiv.org]
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In the case of the LED I'd say you are using the mass of the fuel as a propellant, just a very tiny amount of it (mass/energy equivalence and all). A very inefficient type of drive. A better term for these kinds of drives would be matterless. The propellant is created in situ from the energy released by the fuel in the form of photons.
It's never going to be efficient though, when you have all that spent fuel you might as well accelerate it and use it as propellant ... always going to give you more bang for
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"There's a video of it pushing an experimental apparatus, so it's definitely not an instrumentation thing. I'm not saying it works, I'm just saying that's definitely not it."
(Playing Devil's Advocate here): videos say next to nothing about it. I've seen videos of objects disappearing, and of Faeries. In most cases they are to be disregarded as any evidence of much of anything.
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Re:Skepticism (Score:5, Informative)
Sorry, no. The whole point of skepticism is to assign a negative (false) value to anything but proven assertions.
That's a related concept properly called positivism.
Re:Skepticism (Score:4, Insightful)
"Sorry, no. The whole point of skepticism is to assign a negative (false) value to anything but proven assertions. You may still be in the realm of empiricism, but you are not being skeptical."
Not at all. As a skeptic, it behooves me to judge which is more likely, based on actual evidence. (And if I do the job properly it should be good, solid evidence.) But if I waited until everything was proven I'd be waiting past the heat death of the universe. As "causality" pointed out, what you advocate is positivism, not skepticism.
I'll never understand why simply saying "I really don't know, but it may be possible" is so damned difficult.
It seems to me like another silly ego game to declare something false when it has not been falsified, (ab)using the concept of positivism by taking it to an extreme just so you can tell somebody else that they're wrong. Yes, the burden of proof is indeed on the person making a claim, but hiding behind that to smugly declare that something "is false" is a roundabout way to make a claim yourself (that something is false) while excusing your own burden of proof (falsify it or admit you don't know). It's an attempt to put the other person at a disadvantage to "get even with them" for having a different inclination.
If you look deeply at human behavior, you will see for yourself that most people have a desperate need to feel superior in some way to another human being. It is not enough that someone be right; someone else must also be wrong. It is not enough that someone explains their opinion; someone else's must be bullshit. It's not enough to disagree with something; the other person must be put down or mocked or denigrated in some manner. Always there is an attempt to hide this by giving it the appearance of legitimacy.
Yes, in hard sciences positivism is a good thing. It prevents a lot of pseudoscience and weeds out a lot of false notions. But there is a distinction between "we're going to treat this as though it were false for now, but if you have other evidence please show me" and "this absolutely is false and I'm closing my mind now".
As far as it concerns Slashdot, I wish people would grow up, get some emotional maturity, deal with their petty little insecurities, and realize that the only real sense of worth human beings ever find comes from within yourself. It does not come from the relativity of making another person look worse than yourself and the attempt to do that is completely childish. Sadly it's also accepted as normal because it is so common.
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"It seems to me like another silly ego game to declare something false when it has not been falsified, (ab)using the concept of positivism by taking it to an extreme just so you can tell somebody else that they're wrong."
Yet I have seen it ridiculously often in "scientific" discussions, and it drives me up a wall. I mean it's gotten to the point that sometimes it downright pisses me off.
I am perfectly happy to say "maybe it works, maybe it doesn't, let's wait for tests and evidence". It just drives me nuts to see other people saying "No. It can't be real. It violates my worldview, so it must be false." Without, of course, any actual evidence either way.
Sure... you can say: "I doubt it's real, because it SEEMS to be vi
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http://www.youtube.com/watch?v=KDqh-r8TQgs [youtube.com]
Your post made me smile and remember the soviet headless dog.
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chances are any thrust developed is actually air that's getting heated up and expanding out of the container.
Sure but what if this turns out to be an efficient way to turn a small amout of gas into high energy reaction mass, with a high specific impulse?
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Yeah but this to me looks like an ion thruster with lower specific impulse and higher thrust, because microwaves give the ions less kinetic energy than existing thrusters. There is a niche for high thrust ion drives.
Re:I'm pretty sure it doesn't work (Score:4, Funny)
Good! now we can start building TIE Fighters
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Evidence?
Re:Primitive and woefully inadequate (Score:5, Insightful)
From my perspective, Einstein muddied the entire subject by equating reality with what is observed and using that false premise
The new scientific method is here! Make some wild guess about how the universe must work because that's how you'd like it to work, then call all previous work foolish and flawed. Done. Wait, didn't we used to do something similar to that?
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FTFA:
> Shawyer continued to produce and test more advanced demonstrators, working out elaborate ways of ensuring that the test results are valid and not the result of air currents, friction, ionization, interference or electromagnetic effects.
Re:I'm pretty sure it doesn't work (Score:4, Informative)
Some rather talented scientists evaluated this first hand:
Boeing's Phantom Works, which works on various classified projects and has been involved in space research, went as far as acquiring and testing the EmDrive, but say they are no longer working with Shawyer.
I'm sure if the drive was useful in any meaningful way it would have been utilized. So this does not bode well for the practicality of the drive for real-world applications.
Re:I'm pretty sure it doesn't work (Score:5, Insightful)
I'm sure if the drive was useful in any meaningful way it would have been utilized.
Kind of like if Robertson screws were better than Phillips screws, they would have been utilized by Henry Ford? That stuff often doesn't work out the way sane people think it ought to.
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I'm sure if the drive was useful in any meaningful way it would have been utilized.
Kind of like if Robertson screws were better than Phillips screws, they would have been utilized by Henry Ford? That stuff often doesn't work out the way sane people think it ought to.
Ah, but no one ever said that Robertson screws wouldn't work or violated fundamental laws of physics without explanation. Robertson screws are easily measurable... microwave drives, not so much. Bad analogy on you.
Re:I'm pretty sure it doesn't work (Score:4, Informative)
Ford wanted to use the Robinson since it was shown to be a better screw for mass production, but couldn't come to an agreement with him to license the screws in order to allow them to be made in sufficient quantity for Ford's manufacturing use.
So Ford moved on to another screw type.
Re:I'm pretty sure it doesn't work (Score:5, Interesting)
No, it's not like that at all. Ford didn't choose Phillips over Robertson because Phillips was better, he did it because Robertson wouldn't license the patent and wanted to be the sole supplier. Phillips, on the other hand, did license it, and the rest is history.
On the other hand, this crackpot was so desperate to find someone to license his "drive" to he gave up trying to sell it to any American companies and tried out China...
Re:I'm pretty sure it doesn't work (Score:4, Funny)
And, that makes 3 hands... next time I should proofread to limit my trite opening phrases to one per post :)
Re:I'm pretty sure it doesn't work (Score:4, Funny)
So as usual in capitalist societies, it was all a matter of who screws who.
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No, given their nature, if it worked they would be producing glossy brochures showing spacecraft flying to Mars or where-ever. There is no reason why they would keep this a secret; the spy satellite world is not suffering from a lack of reaction mass. If they even thought it possibly could work, they would hire Shawyer.
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They wouldn't if Shaywer had independently produced something that Boeing had already developed as part of a black project.
Re:I'm pretty sure it doesn't work (Score:4, Interesting)
No, given their nature, if it worked they would be producing glossy brochures showing spacecraft flying to Mars or where-ever.
While that might be true for Boeing in general, for true black project departments, this is a no-no. For example, at Perkin Elmer, which was doing the engineering for the KH-9, one of the engineers had a heart attack on the job and died. The other engineers were not permitted to tell the guy's widow even how he died (e.g. peacefully, etc.) until after the project was declassified some 25 years after the last KH-9 was decommissioned. That's how secretive they can be.
There is no reason why they would keep this a secret;
Once again, I think you underestimate just how deep and dark these projects sometimes are.
the spy satellite world is not suffering from a lack of reaction mass.
Most KH satellites don't just go around in a fixed [polar] orbit. Their orbits must be constantly adjusted so they can observe a trouble spot in real time (e.g. they can't wait 5 days for the orbit to pass over the spot naturally--they must burn fuel to change the orbit so it's in the right place on the next pass). Considerable mathematical effort is expended in the orbital adjustment calculations, designed to minimize the fuel cost of adjusting the orbit. Sometimes, compromises have to be made, to conserving fuel cost against getting there ASAP. Having a satellite that has no such downside, would be a [closely guarded] strategic advantage.
If they even thought it possibly could work, they would hire Shawyer.
Given that he's a U.K. citizen, it's unlikely he could get the security clearance necessary. Or, the Phantom Works people had reservations about him specifically, for whatever reason (e.g. either his general ability to work well with others, or his desire to keep his work public--to name just a few).
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Boeing's Phantom Works, which works on various classified projects and has been involved in space research, went as far as acquiring and testing the EmDrive, but say they are no longer working with Shawyer.
I'm sure if the drive was useful in any meaningful way it would have been utilized.
Maybe (though Western Union first dismissed the telephone as a worthless toy). But note that they didn't say they weren't using the drive, or principles thereof. They just said they weren't working with Shawyer. If it's classified, who would know if you were infringing on a... does Shawyer even have a patent?
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> Government work cannot infringe a patent, because the
> government was kind enough to give itself an exemption.
Not true in the USA. They can, of course, practice your patent even if you refuse to give them permission, but doing so is an eminent domain taking and so you can go to court and get compensation.
Re:I'm pretty sure it doesn't work (Score:5, Insightful)
I first saw a working model of a scramjet in 1986. It wasn't the first one. now it's 2013 and it hasn't been "utilized" yet in a "real-world application" but it is on track to do so. That should show you that you can't expect instant results with propulsion systems and that your assumption that something is worthless if you don't get quick results is wrong. Instead the thing itself has to be considered on it's own merits and not whether it's on the shelf at Walmart yet. There are plenty of reasons why Boeing may not immediately jump on a new and unproved technology that have nothing to do with whether it's viable or not. We'll need to get information from another source instead of just making a wild assumption based on it not being commercially available this instant or other unreasonable expectations.
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This device, on the other hand, seems to be an implementation before there is a theory of how it could possibly work in a vacuum. In other words, we should most certainly be skeptical of what the supposed observed results mean because it simply doesnt make any theoretical sense that it would work in a vacuum.
Consider the team that reported f
FAQ from Dr. Shawyer answers a lot of questions. (Score:5, Informative)
Here are some of the FAQ answers:
Q. Why does the EmDrive not contravene the conservation of momentum when it operates in free space?
A. The EmDrive cannot violate the conservation of momentum. The electromagnetic wave momentum is built up in the resonating cavity, and is transferred to the end walls upon reflection. The momentum gained by the EmDrive plus the momentum lost by the electromagnetic wave equals zero. The direction and acceleration that is measured, when the EmDrive is tested on a dynamic test rig, comply with Newtons laws and confirm that the law of conservation of momentum is satisfied.
Q. Are there any convection currents which might affect the results?
A. Convection currents did not affect the results, as measurements were taken with the thrust vector up, down and horizontal. Test runs were also carried out using a thermal simulation heater to quantify the effects of change of coolant temperature.
Q. Have electromagnetic effects been taken into account? These include interactions between current-carrying conductors and between such conductors carrying RF currents and nearby metallic structures in which currents might be induced.
A. Stray electromagnetic effects were eliminated by using different test rigs, by testing two thrusters with very different mounting structures, and by changing the orientation by 90 degrees to eliminate the Earth’s magnetic field.
Re:FAQ from Dr. Shawyer answers a lot of questions (Score:5, Insightful)
It blatantly violates conservation of both momentum and energy. It's advertised as being useful for spacecraft propulsion, changing the momentum of the spacecraft without emitting anything that would carry equal momentum in the opposite direction. If Shawyer's claims were true, an EmDrive placed on end in a gravity field would be either an energy sink or source (depending on orientation) with infinite capacity. I see no reason why anything else on the site should be treated as any more trustworthy.
Re:FAQ from Dr. Shawyer answers a lot of questions (Score:5, Informative)
EM can serve as reaction mass, but it creates very little momentum.
This shows the problem :
http://en.wikipedia.org/wiki/Nuclear_photonic_rocket [wikipedia.org]
PS. with antimatter/matter fuel a photonic drive would make sense.
Re:I'm pretty sure it doesn't work (Score:4, Insightful)
Considering that energy must be supplied to it, it no more violates conservation than an electric motor.
How about a different headline.... (Score:5, Funny)
Re:How about a different headline.... (Score:5, Funny)
The most inviolable law in the universe is that everything flies pointy end first.
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The most inviolable law in the universe is that everything flies pointy end first.
Actually it's that there's no limit to human stupidity. Oh, and the chinese astronauts will probably die of lead poisoning shortly after returning.
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The most inviolable law in the universe is that everything flies pointy end first.
That's Hollywood's view. In their view, explosions in space make big booming sounds and fast things make zooming sounds.
Re: everything flies pointy end first. (Score:2)
http://www.youtube.com/watch?v=dmLh1sSFs8Y [youtube.com]
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Indeed. Even classical mechanics already states this cannot work.
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Indeed. Even classical mechanics already states this cannot work.
Of course, it's good to be open to new physics and ideas, but this guy needs to come up with a plausible mechanism for how this could work, and at a minimum he needs to tell people how he did it, so we can reproduce it.
He doesn't do that, instead he talks about how none of his critics actually examined his device. Right. I hope this guy has an IPO so I can short his stock.
We can always hope, but... (Score:2)
...you'd think that if high energy in a closed, conical microwave cavity produced thrust, someone would have noticed before this. We've done a lot of work with microwaves.
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...you'd think that if high energy in a closed, conical microwave cavity produced thrust, someone would have noticed before this. We've done a lot of work with microwaves.
Of course it does, there are photons coming out of it.
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Yes, but they are VERY light photons
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...you'd think that if high energy in a closed, conical microwave cavity produced thrust, someone would have noticed before this. We've done a lot of work with microwaves.
"You'd think that if the world were a sphere circling the Sun, someone would have noticed before this." I imagine Copernicus hearing something along those lines, then Galileo.
Re:We can always hope, but... (Score:4, Insightful)
If you imagine that - you need to study up on your history. It was known that the earth was round and orbited the sun a long, long time before those two showed up.
Doesn't work (Score:5, Insightful)
From the article: "Seems to violate law of conservation of momentum". - Yup it does. Imagine putting an invisible mass-less box around the entire system. Almost nothing comes out the back (only microwave energy - more on that later). The center of mass of the box accelerates. This is a violation of conservation of momentum - one of the most well understood and best tested laws in physics. If there were some exotic high energy physics effect proposed for this at least it might be worth listening, but this is just electromagnetism - very well understood. The "group velocity / phase velocity" is just jargon that has nothing to do with this since it is the Poynting vector that carries momentum.
You CAN make a reaction drive using photons (microwaves in this case), this idea has been around for many decades. The problem is that photons carry a lot of energy relative to their momentum so it takes an enormous power source to produce any thrust. So far no one has found a practical application where there was a large enough energy (and high enough power ) source to make this practical.
There have been a lot of experiments with microwaves - I've personally worked on a 600MW pulse microwave system. There have even been attempts at microwave driven spacecraft sails. Some early experiments seemed to indicate more thrust than would be expected from momentum conservation. Eventually this was tracked down to gas absorbed on the surface being heated and released by the microwaves - essentially a conventional rocket. With very high microwave powers you can generate forces in all sorts of ways in a closed laboratory environment that would not work in space.
This will not work.
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From the article: "Seems to violate law of conservation of momentum". - Yup it does.
And from the article, in more detail: "It seems to violate of the law of conservation of momentum, implied by Newton, which says that no closed system can have a net thrust. However, Shawyer says net thrust occurs because the microwaves have a group velocity which is greater in one direction than the other and Einstein's relativity comes into play."
Is the article and/or Shawyer trying to say here that "Einstein's relativity" magically makes the law of conservation of momentum go away (perhaps the idea is t
Re:Doesn't work (Score:5, Interesting)
Conservation of momentum is extended in relativity to conservation of 4-momentum, basically a combination of momentum and energy. In a rest frame this means that standard Newtonian momentum is conserved, it just makes conservation also work when you are observing a system that is moving past you at relativistic speeds.
Re:Doesn't work (Score:5, Funny)
It's not a device for extracting momentum from the relativistic differences between the group and phase velocity of resonating microwaves.
It's a device for extracting money from people who don't understand physics.
I would call this device a total success so far.
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And for everyone still reading: that's where it all ends. Nothing more to be said. Anyone who's not deluded understands that seeing any measurable thrust in such experiments is a prima facie evidence that your experimental method is broken. The better your experiment, the less thrust you should measure. That's all there's to it. Undergrad physics lab, it sounds like -- to me at least.
There's also some indirect evidence of fraud, even if non willful. How the heck is it that all such "genius", "unappreciated"
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I'd agree with all that except that its actually tricky to do the experiment correctly. With lots of microwave power, high currents, etc in the system it would be easy to fool yourself. Of course if you have any brains you know it can't work from first principals and wouldn't' bother trying.
Re:Doesn't work (Score:4, Insightful)
I do know that it's tricky to do this stuff correctly, that why you should doubt yourself more when faced with supposedly extraordinary results. Doubt more, not less. All I remember from numerous labs that extraordinary results meant you'd have to keep redoing it until it got ordinary again. I'd have really thought that people who did any sort of engineering or physics undergrad labs should have had such basics explained to them. I'm playing with getting the 4th digit to agree well with theory in a simple mechanical pendulum, and the dreaded thing highlights that everything you thought could be ignored, can't. You have to engineer it to work -- look at all the numbers, for all effects you can think of, estimate their magnitudes, verify that you do in fact see the effects, and then mitigate. Good old experimental engineering. You get small but cumulative payoffs for diligence and a certain sense of accomplishment -- I do at least. Simple life's pleasures :)
This non-drive, given the power pumped into it, simply magnifies all the effects people can ordinarily ignore. It's a nice educational tool. I think good schools should add such a thing to their lab curriculum, so that the students will get some experience in how easy it is to fool oneself. There are probably other similarly spectacular experiments that would serve the same purpose, of course -- even a basic large mechanical pendulum.
I can't get over the fact that people with money who fund that sort of thing are so gullible, though. I mean, give me a fucking break, they seem to be just as gullible as the investors were 100+ years ago when faced with all sorts bullshit when the telegraph, telephone and electricity were getting into high gear. Hans Camenzind's little jewel of a book "Much ado about almost nothing. Man's encounter with the electron" is a sad testament to how little things change in that respect. The dumb will be parted with their money, all the time, all the same.
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Bravo, Joe. It's another water carburetor, and your explanation is succinct and to the point. Props.
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Since when is magnetism a closed system within range of the Earth or Sun?
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I've personally worked on a 600MW pulse microwave system.
Yes, but did you work with resonating microwaves? Clearly that is how this guy can violate the law of thermodynamics (I would mock you now but my sarcasm wouldn't come through).
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In fact the 600MW were used to drive microwave resonators (X-band accelerator structures). Not only that but they had different group and phase velocities. I guess I should be surprised they didn't launch themselves into low earth orbit....
Maybe we should have used Tesla coils instead,
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Well, you'd be fascinated and intrigued by this new research and working model then? surely?
Surely you'd be interested in replicating his experiment, if only to prove it doesn't work.
Seems to be there's a lot of not-science going on here...
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Actually, the burden is on the promoter to prove that it DOES work. Until then, I have the position it doesn't, and I don't need to provide a thought experiment or anything else.
Indeed. The claim basically violates a lot of _very_ well established physical principles. By "Extraordinary claims require extraordinary evidence" (Carl Sagan), this is already a complete fail. They do not even have the evidence ordinarily required to demonstrate that a propulsion engine works, namely a test in a vacuum chamber.
Hence I deduce this is just an ordinary scam, in line with countless others. That explanation fits the facts very well.
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Nope, GP is right. They accounted for radiation pressure with the paragraph "You CAN make a reaction drive using photons...". But the EM drive doesn't emit photons, so it can't work like this. The comment you criticize is at a much higher level of understanding than yours.
By the logic of the EM drive, a champagne bottle would also accelerate, as it is also a pressurized (approximately) conical volume.
The EM drive claims to mix a bunch of standard physics (Newtonian mechanics, electromagnetism, special relat
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Whatever happens in the box, the momentum change of the engine will be the same as the amount of momentum that exits as exhaust. If the only thing that exits the system is photons, then the ratio of power to thrust is extremely large - it is not a useful means of propulsion for any application that I can think of (not counting antimatter powered starships that is).
Ridiculed Brit? (Score:2, Funny)
So they found the guy who invented the Triumph?
emdrive.com web site explains the theory (Score:2)
http://emdrive.com/principle.html [emdrive.com]
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I want it to be true, but I'd bet against it:
http://xkcd.com/955/ [xkcd.com]
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There is a description of the Sagnac effect on wikipedia, this is the basis of a laser gyroscope. Interestingly Newtonian physics and relativity give the same answer for this. I isn't related to the microwave drive. I think they mention it because laser gyroscopes are conceptually complicated and they hope that the reader won't understand them, and therefor not understand that if anything they are yet more evidence that this trick doesn't work.
Ungrounded assumptions (Score:4, Informative)
From TFA: Propellant can account for as much as half the launch weight of a geostationary satellite. This means that, in principle, fitting one with an EmDrive rather than a conventional drive, could halve launch costs.
That depends entirely on the power system needed to operate the drive. That's the real Achilles heel of various non chemical propulsion systems - they eat a lot of juice and the resulting power supplies negate most (if not all and then some) of the savings of not carrying conventional fuel.
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They say the existing unit uses about half as much power to produce 4 times the thrust of the ion drive.
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And unicorns fart rainbows.
It's a magic drive. It doesn't produce any thrust.
Yes, but think of the advantages. It can have any weight or power consumption you want ! (For a small additional fee, natch.)
Are there plans so I can try it myself? (Score:2)
It doesn't sound very sophisticated, are there plans anywhere so I can build one and see for myself?
Without wanting to comment on this particular (Score:5, Insightful)
experiment (since IANAP), I do want to say that there seems to be a troubling trend amongst the best and the brightest in many STEM fields to mistake theory for reality. Theory is great and proceeds under the scientific method from empirical observation, but as we've seen throughout history, new phenomena and corner cases to arise and require theory to be amended.
It's fine to say "this is clearly unlikely to work under current theoretical understandings" but let's also refine and do the experiments to the best of our ability so that science remains scientific (i.e. nominally empirical and ultimately practical in nature). There's a difference between taking "current theory suggests this is likely to fail" as a statement of fact and mistaking theory instead to be *evidence* about experimental outcomes.
No theoretical argument can be evidence for the reality or unreality of phenomena, no matter how well-formed. That's not to say that we ought to mistake the phenomena at issue—it's obviously critical to be able to understand, rather than misconstrue, the reality that we observe—only that sometimes a generation or two of scientists seem to get complacent and imagine that they've got the world all figured out after all.
Let's continue to do, and—to the best of our ability and within reason (but with "within reason" here broadly defined—allocate resources for, actual experimentation and empirical observation of the world around us.
Not that we don't—but to my eye, the attitude that if theory doesn't support it, it's always a waste of money to test it out experimentally, is a dangerous one for the future of a science that is far less uniform, linear, and accumulative in its progress than we often tend to remember.
Re:Without wanting to comment on this particular (Score:5, Informative)
experiment (since IANAP), I do want to say that there seems to be a troubling trend amongst the best and the brightest in many STEM fields to mistake theory for reality. Theory is great and proceeds under the scientific method from empirical observation, but as we've seen throughout history, new phenomena and corner cases to arise and require theory to be amended.
While it is certainly worthwhile to keep an open mind and question our assumptions, there are a variety of different levels of confidence we have in different ideas. The major conservation laws (linear momentum, energy, angular momentum) are mathematically equivalent (via Noether's theorem) to symmetries of the space. If the laws of motion are independent of position then linear momentum is conserved. If linear momentum is not conserved, than the laws of motion are not independent of position. (similarly for rotation invariance angular momentum conservation and time invariance conservation of energy).
http://en.wikipedia.org/wiki/Noether's_theorem [wikipedia.org]
So this goes way beyond understanding of EM theory - if we have a case where momentum is not conserved, that will fundamentally change how we think the universe is put together. In my mind it is much much much more likely that there is error or fraud or psychosis than momentum is not being conserved.
Re:Without wanting to comment on this particular (Score:5, Insightful)
Agreed.
Also just trying random stuff to see what happens is likely to end up with experiments that are subject to all sorts experimental errors. If you have a theory that electromagnetic radiation doesn't conserve momentum, then you design a specific experiment to look: If you think its a high field effect, you do particle collisions, or relativistic particles in intense laser beams. If you think its a small but linear effect you do superconducting microwave cavities suspended on ultra-sensitive force balances. You don't start out trying to build a rocket engine.
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Please stop the BS. The effect you describe does not exist. We just know enough with high probability that a lot can be ruled out. There is room for residual uncertainty, i.e. deviation between theory and reality, but it is not large.
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And the most annoying tendency amongst people outside of STEM disciplines is the conflation of the terms hypothesis and theory.
BS (Score:4, Funny)
All the usual signs of pseudoscience.
Show it works (note : that is not the same as saying that you have shown it works), and I'll be interested. Until then, this goes in the cold fusion circular file.
"Flying Cars"? WTF? (Score:2)
Is it non-sense time again? Flying cars are a bad idea for a large number of reasons. Those that still ignore this are not qualified to report on anything in science or technology.
It *is* possible to build a reactionless drive... (Score:5, Informative)
... sort of. And it is established physics. See Swimming in Spacetime: Motion by Cyclic Changes in Body Shape [mit.edu], Science, 2/27/2003, by Jack Wisdom.
But this mechanism relies on general relativistic effects, and only works in curved spacetime. Momentum conservation is not violated, because while the location of the object changes, its momentum (thus velocity) does not -- it simply cyclicly translates itself through space.
My first thought reading about the EmDrive was that Shaywer had found a way to reproduce this effect using a microwave cavity. But unless I'm mistaken, this does not appear to be the case, and I don't follow the arguments that Shaywer's drive should work.
what? (Score:5, Funny)
I find it hard to believe that the Nation that is home to the Ministry of Silly Walks has ridiculed a scientist for his strange ideas. . .
Re:this post will be remembered (Score:5, Funny)
No more Anonymous Coward posts? Whatever shall we do?
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Riiight. Get back to us when one of those "inventions" that break the laws of physics to work aren't bunk.
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http://www.youtube.com/watch?v=L397TWLwrUU [youtube.com]
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If you are conducting experiments that violate fundamental physics they will fail every single time. You can't beat the laws that govern the universe.
Do you honestly believe that this guy has discovered a fundamental principle of the universe that violates principles that have been known and tested for almost 400 years? EM emissions, Microwaves and EM generated thrust are some of the most studied areas of human knowledge. I wouldn't bet a penny that this guy has figured out anything but how to separate unsu
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And if you had ignored all the people who said "you can't do that" or "it won't work" or "no one has ever done that", you... probably wouldn't have survived grad school in chemistry. Or, for that matter, driver's education.
Sometimes, when everybody says you're wrong, it's because you're wrong.
You never know how far you go until you finish failing.
I don't know how far you're going to go with this.
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And in related news, there is a sucker born every minute and you are right on time. There _are_ people that had breakthrough insights and had trouble publishing as a result. But these were never scientifically deconstructed, but always "because that is not the way to do it". But there never, ever has been anyone that apparently managed to violate fundamental laws of physics as understood for about a century in a macroscopic context that was not a fraud. There have been lots of frauds though.
So, no, it is qu
Re:Conservation of momentum (Score:4, Insightful)
A surprisingly non-sceptical article; I'd expect a bit more critical thinking from Wired. Terms like "group velocity" and quantum theory", used vaguely, don't help you avoid the fact that conservation of momentum is fundamental to modern physics. It's just as inviolable as conservation of energy.
To put it another way, this article makes Wired look just as gullible as they would if they wrote "Scientists in China have built and tested a perpetual motion machine."
It's really the same thing as the conservation of energy. What we really have is the conservation of four-momentum, which is standard special relativity. You can Lorentz transform one (energy) into another (momentum) (within limits).
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Yeah, you should stick to reputable magazines like "New Scientist" [wikipedia.org] instead.
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The EM drive doesn't hypothesize any new science, it claims that our existing science can give this reactionless drive. That is provably wrong, as they've combined a bunch of physics which all conserves momentum and claimed a result which does not conserve momentum.
Just possibly their device might work, due to new physics. But as their explanation is provably wrong, if it did work, it would be a complete fluke. In other words, constructing an EM drive is no more or less likely to demonstrate new physics tha
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