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Thrust from Microwaves - The Relativity Drive
dfenstrate writes "The latest New Scientist has an article about an engine that exploits relativity and microwaves to generate thrust. There is a working prototype." From the article: "Roger Shawyer has developed an engine with no moving parts that he believes can replace rockets and make trains, planes and automobiles obsolete ... The device that has sparked their interest is an engine that generates thrust purely from electromagnetic radiation — microwaves to be precise — by exploiting the strange properties of relativity. It has no moving parts, and releases no exhaust or noxious emissions. Potentially, it could pack the punch of a rocket in a box the size of a suitcase. It could one day replace the engines on almost any spacecraft. More advanced versions might allow cars to lift from the ground and hover."
It does seem rather bogus
His references include an undergrad level textbook on physics, as opposed to the usual slew of papers outlining new developments in the field. Undergrad physics books are geared towards undergrad courses... which is why you see things like: "assume no friction due to air" in trajectory problems. His second reference is Maxwell's treaty on electricity and magnetism... hardly a new work.
In short, odds are he picked up a textbook and started playing with simplified equations and figures he's made a "discovery" that no one else has noticed until now.... HUGE HUGE Kudos if it's true.... but the magic 8-ball's sayin "outcome not likely"
Oh god, that woman is John Romero!
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Joke well taken, but in all honesty the bigger joke is that we technically could have had flying cars already. You know what the problem is? the general public couldn't be trusted not to crash the things left and right. In no time there would be more flying lawsuits than cars.
I hope his invention is better than his explanations for why he has no investors (I know, I know, it's not).
"'Yrch!' said Legolas, falling into his own tongue."
Assuming that part of TFA is true, then he's already way ahead of the usual "free energy" crowds.
Typically when somebody's claims violate the laws of physics, the usual challenge is for them to provide a repeatable experiment for others to test the theory in question with. This challenge is most often met with weaseling or silence. When such theories are tested from outside, they most often do not pan out (see the cold fusion experiments as an example).
If he's willing to get outside review already, then I at least will acknowledge that he is an honest crackpot rather than a snake oil salesmen. And it's always better to actually test the blue sky ideas than it is to dismiss them out of hand.
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It's a bit harder to drive your car into the side of a highrise buidling.
It's possible that it's covered more accurately in his paper, I haven't got around to reading that yet, but TFA is certainly not the place to go for a serious treatment of this information.
Yes, that's the part where you should finally realize the whole thing is nothing but bullshit.
He's claiming that the effect depends on the absolute velocity of the engine - a concept that has been meaningless ever since we did away with the coelestial aether and Maxwellian electrodynamics.
He's not using relativity, he's using the exact opposite.
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But, he does claim to have a working prototype, and it will be interesting to see if anything does come of it. I've been known to be wrong in the past, after all.
It really is sad that NewScientist published this. When I was a grad student we used to get sent the crackpot letters addressed to the professors - its an education! In this case the 'crackpot' signs are all around.
/.ers commented that at least there were some experiments, presumably a reference to:
Some
"by mounting it on a sensitive balance, he has shown that it generates about 16 millinewtons of thrust, using 1 kilowatt of electrical power."
One of the many problems here is how incredibly easy it is to stuff up sensitive measurements. For example, I have seen electronic balances and other equipment read a lot more than 16mN in error due to em interference (could be the microwaves, could be slop-over RF, could be induction into the mains. Remember Cold Fusion? Did you know the neutron detectors they were using were incredibly sensitive to temperature? No? Nor did Pons and Fleischmann, unfortunately...
In theory, there's no difference between theory and practice; in practice there is.
Is anyone else reminded...of those cartoons where Bugs Bunny or someone is sitting in a sailboat, pulls out a fan, aims it at the sail... ...and the boat moves?
That actually works. A little bit.
But it works MUCH BETTER if you just point the fan to the rear.
The fan sucks air from a lot of directions and ejects it in one direction, creating a net thrust (and reaction - backward - on the boat via the person holding the fan) and a net wind.
Diverting that wind to the rear via the sail produces somewhat more reaction forward on the boat via the sail and the mast than the reaction backward from the fan - IF the trim is good enough that the diverted wind ends up going backward rather than just off to the sides. Result: Slight net forward thrust on the boat.
But pointing the fan to the rear - using it as a jet - eliminates the inefficiencies of using the sail in this way, putting the fan's whole reaction into moving the boat forward.
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He then proceeds to derive a maximum speed this engine can attain, relative to this arbitrary stationary frame, to illustrate the consequences of this idea. He has, as far as I can see, recreated the ether in his attempt to justify the machine using relativity.
Um, I have to ask. What about the air being deflected off the fan? Doesn't it create thrust in the opposite direction from the sail? In fact, I'd expect the boat to move backward, because most of the air from the fan would disperse and not hit the sail.
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If there is a sustained, measurable deviation not explained by known physics, the guy will get a Nobel. That's 1.1 million dollars. If I was sure I had a winner for getting a million, I'd certainly be ready to invest into a vaccum chamber and build a prototype.
If we don't see this happen, then the drive doesn't work. End of story.
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Newton was wrong with his description of gravity. It was the best he could do to describe it, however in the end, its wrong. Could this be the same?
Almost certainly not. Newton's Laws were incomplete, not wrong. Newton's Laws are today seen as a mere special case of General Relativity, and yet we still use Newton's Laws on a day to day basis, and when some new theory of quantum gravity replaces GR, Newton's Laws will still be used on a day to day basis, because they're not wrong.
The "EMDrive", on the other hand, would throw out one of the most established principles of physics, Conservation of Momentum, a principle found in every coherent system of physics a human being has ever written (at least, those systems of physics meant to describe the universe we live in). And while it's conceivable that we really do need to rewrite the physics textbooks from scratch and add an error bar to Conservation of Momentum (then figure out why it's possible to break it in the first place), the article hardly constitutes a good reason to do so. Science isn't done by asking "Wouldn't it be great if X were possible?"
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But what really got me fuming wasn't the author's total failure to notice that any of these were an issue - which I'll grant got me quite livid, being as bad as a football report from someone who doesn't know the offside rule. That it violates basic physics is bad, and should certainly have been seriously raised as an issue in the article, but if it works then that's just too bad for basic physics.
What upset me most of all was the lack of imagination. What if this thing works as advertised? Oh, then we can have planes that work a bit differently. Hovercars, perhaps. For the love of God, man, it's a reactionless drive! Strap a few to a nuclear reactor and go to Saturn and back in a week! A rocket that doesn't have to carry vast tanks of reaction mass around with it? The whole galaxy would open up!
I'll buy this week's New Scientist in the hope of some sort of grovelling apology for this appalling mess of an article. Or at least of a proper flaming of the editors in the letters pages. And then I think I'll see if I can't get a reliable supply of Scientific American - it's quite scarce in UK newsagents but always has some really solid science in it.
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