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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."
"The latest New Scientist has an article about an engine that exploits relativity and microwaves to generate thrust.
That sounds a bit more advanced than these two guys, who exploit explosives and a microwave to generate thrust.
The theory of relativity doesn't work right in Arkansas.
A) Any pressure from the microwaves on the walls.
and
B) Conservation of Momentum
Ewige Blumenkraft.
It also warms soup, and is great for reheating food.
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
Of course, his first effort was to create a drive that ran purely on improbability, but you could never be sure where you'd end up or even what species you'd be when you get there.
The theory of relativity doesn't work right in Arkansas.
Seriously, we were supposed to have these things *years* ago. The scientific community should be ashamed of themselves.
( yes, this is a joke )
Mod me down with all of your hatred and your journey towards the dark side will be complete!
The complete and utter bogosity of this story has prompted Greg Egan to try to start a movement to save New Scientist. Anyway, check out this story.
Doesn't it make you feel good to know that our freedoms are protected by politicans, lawyers and journalists.
Interesting post from the aRocket list, that basically blows up this guy's argument. At least, this guy SOUNDS like he knows what he's talking about... Peter Fairbrother zenadsl6186 at zen.co.uk Tue Sep 19 17:56:42 PDT 2006 Russell McMahon wrote: > As already noted on ARocket - it "*can't* work - but wouldn't it be nice if he > was right, even though he's not :-(.
I don't know that a reactionless drive can't work - although I don't know
how to build one :( - but I do know that this particular one doesn't work.
> For those who haven't met the emdrive before - it's not your usual snake oil
> and mirrors type device - the inventor is highly capable and has convinced a
> number of substantial organisations, including the US Air Force, British Govt
> research granters and NASA to be cautiously interested. All of which just
> means that it's not yet obvious to all where the hole in his theory is.
>
Without having gone into it in detail, his math seems okay up to eq 6 (when
he is quoting well-known math), but thereafter he veers into the realms of
error and fantasy.
Eqation 7 is incorrect in so far as it purports to describe the total forces
on the waveguide - while it does correctly describe the sum of the
forces on the ends of the waveguide, it does not take into account the
forces produced on the sides of the tapered waveguide.*
All by itself that is enough to blow the conclusions of the paper completely
out of the water. It is simply wrong. It doesn't work. You can stop reading
here.
Now we get into the rather more dubious portion of the paper.
Eq. 8 is also in error - it is based on the incorrect statement " ...as the
two forces Fg1 and Fg2 are dependent upon the velocities vg1 and vg2, the
thrust T should be calculated according to Einsteins law of addition of
velocities." - but the conclusion does not follow, and use of Einstein's
equation is inappropriate. There is no real-world summing of velocities, it
is a mathematical trick (and there is an error int the math too). The ends
of the waveguide are stationary relative to each other.
That is an elementary schoolboy (or snake-oil salesman's) mistake.
There are several other obvious mistakes in the paper, and he frequently
states as fact things that are unjustified and on occasion untrue. There are
also parts of it which seem to be meaningless.
For example, this is also incorrect: "The second effect is that as the beam
velocities are not directly dependent on any velocity of the waveguide, the
beam and waveguide form an open system."
The conclusion does not follow.
This is actually very confused - I don't think he even knows what he is
saying. Relativity theory does not (directly) come into it at all.
I stopped looking for more errors about here.
Snake oil or error?
There was some mention of licencing the technology, but as it is in the UK
patenting it here would be impossible - it is, after all, a perpetual motion
machine (or it would be if Q approached infinity, which there seems no
theoretical reason to suppose impossible), and you cannot patent a perpetual
motion machine in the UK.
Even if it worked.
The question of how he got a grant is still ... puzzling, but not totally
unexpected. Grants are often assigned by managers and politicians rather
than scientists or engineers.
To the DTI, NASA etc: Please can I have half his grant for pointing out his
mistakes? I promise I will use it do space r+d. :)
*Of course if you want to consider the waveguide as two pieces, forces on
the tapered walls do not affect the result - but the math in eq7 would be
wrong if you are looking at it that way, eg the lambda-g1 and lambda_g2
figures are for the ends of the waveguide, not the middle.
I think he first went wrong in his mind here - in fig 2.4 there is a
vertical line in the middle of the diagram, implying that he was looking at
the waveguide as two pieces, rather than as two ends and a tapered middle.
You can of course look at it in either way, but in his analysis (even before
we get into the error-full "relativity" stuff) he is trying to do both at
once, and that will and has lead to error.
--
Peter Fairbrother
Slashdot never loses its appetite for junk science, it seems. Couldn't we at least file this crap under "humor"?
"In this house we obey the Laws of Conservation of Momentum!"
What's the difference between letting the microwaves bounce around in a cavity and just shooting them out the back? Or if you must bounce them, just bounce them off a 45 degree reflector. What's the benefit of the multiple bounces?
I wouldn't tell anyone. I'd maybe show a few keen investors what my prototype could do, but that's it. Then I'd develop a flying car, a launch vehicle, whatever, and insidiously take over existing markets. "So, SpaceX has made you the best offer for launch services eh? I'll beat it." "What kind of safety guarentees can you give us?" "Err, umm, what kind of safety guarentee is SpaceX giving you, I'll beat it!" "Right.. hmm, ok. You don't even have a rocket do you?" "Look, do you want your satelite in orbit or what?" and so on. That's me though, could be this guy just doesn't have balls that big.
How we know is more important than what we know.
More advanced versions might allow cars to lift from the ground and hover. Correct me if I'm wrong, but aren't microwaves dangerous? In space, hardly anyone is around so blasting microwaves all over the place doesn't hurt anyone, but on a crowded street, wouldn't it harm people?
However, it talks about hovering. There's nothing intrinsically unscientifically sound about two black boxes that exert a force on each other despite being physically disconnected (think maglev), effectively hovering one on the other - the transmission of force just doesn't happen via a physical carrier. I, for one, look forward to my hoverboard.
I am one of many. My idea is not unique, nor do I expect my voice alone to sway you. I speak in a chorus of opinion.
Would somebody please just go right ahead and post a scanned copy of Roger Shawyer's maths paper online after tracking him down and ordering the paper version from him? He says he has a maths paper, so let's cut out these waffling, nonsensically hand-waving explanations much loved by New Scientist that "relativity somehow causes microwaves to create thrust but we don't really know how it works but it does because I say so" and see the maths paper. Show us the maths and it will quickly become apparent whether he is a quack or a clever guy deliberately being a honeypot taggant for Chinese military procurement folks.
1 kilowatt for 16 millinewtons of force.
He'd probably have better luck with an ion drive.
- The law of conservation of momentum is never violated.
- The drive is a closed system.
- So it cannot accelerate.
Also he made a mistake in his calculations. The forces at the end might be different, but forces aren't only being exterted on the ends.Inventions have long since reached their limit, and I see no hope for further development.-- Frontinus, 1st cent. AD
you can have it for free:
</i>
If you don't know what AltaVista is (was), get off my lawn.
Finally a use for microwave burritos!!
Because that would be a photon drive. And we already know how well those work - the amount of energy you need to input to get even a tiny amount of thrust out of them is astronomical (pun not intended). We've had the basic idea of light propulsion for at least fifty years, and it's been a major cornerstone of hard science fiction. But it just isn't workable with modern power generation.
You could describe either a photon drive, or it's passive counterpart, the light sail, as a "relativity drive", since they too operate on the oddities of conservation of momentum as it applies to light. Doesn't mean we're going to be using them in lieu of rockets anytime in the next few centuries.
Either this guy has found a revolutionary new way to build a photon drive (and I'm more than a little skeptical), or else the device doesn't actually work. I'm more optimistic about this than I am about the usual lot of crackpot science, since from TFA it sounds like this guy is applying good scientific procedures to his work (documenting, trying to get outside review), but I'm not exactly holding my breath.
Erotic is when you use a feather. Exotic is when you use the whole chicken.
Um, I didn't read TFA, but wouldln't this require a power source? Specifically, eletricity? How does one generate that much wattage? Flux capacitor?
-matthew
"THERE IS NO JUSTICE, THERE IS ONLY ME." -Death
...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?
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The benefit of the multiple bounces is that they never leave the chamber. The chamber is shaped like a horn, and he's claiming that the force on the big part of the horn is greater than the forces towards the little side of the horn. An imbalanced force inside the chamber result in a net force from a closed system. Plus side, no moving parts and sealed. Minus side, current physics indicate this to be impossible. I know of no theory, even including the magical "relativistic" physics that allow for or predict unbalanced forces in a closed system. I'll believe it when I see it demonstrated to move a satellite in space. If he can do that, I'll drink the cool-aid.
Learn to love Alaska
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."
I'd call it the em-motive... or e-motive (if it weren't for IBM's probable copyright for e-anything) e
Mi domando chi à il mandante di tutte le cazzate che faccio - Altan
Now I can have what I've always dreamed of, a flying car with a Phantom game console running Duke Nuke'em Forever on HURD with Copland running in virtualization on a BitBoys Oy Glaze3D graphics system whose driver was programmed in Perl 6 running on top of Parrot!
I love it when dreams come true.
Use really dark window tinting and dont' put your real license plate on the flying car! Also, use that rubbery bouncy paint.
Isn't that the same for every rocket engine? If you burn one unit of fuel to get 1/2 light speed, burning a second unit of fuel will not get you to lightspeed.
I'm rolling on the floor laughing at that article, but have to remind myself that it's probably an ignorant reporter and (not necessarily) Shawyer.
"Since the microwave photons in the waveguide are travelling close to the speed of light"... no, the microwave photons ARE light and are, by definition, moving at the speed of light at that point. I'm not really weaseling -- 'c' is the speed of light in open vacuum and is the same thing for all photons, but a waveguide is only a few multiples of the photon's wavelength and various weird things (to us) happen. See also the (Shamir?) pressure you can get when you hold two conductive plates close together. Longer wavelengths can't exist between the plates but can exist outside of them so you get a very slight net force pushing the plates together.
"any attempt to resolve the forces they generate must take account of Einstein's special theory of relativity."... no, standard EM theory will suffice. (Well, you might need some QM in there, but definitely not special relativity.)
and my favorite
"by mounting it on a sensitive balance, he has shown that it generates about 16 millinewtons of thrust, using 1 kilowatt of electrical power."
Let that sink in. This is as much power as a hair dryer or stove element, and it generates 16 mN of thrust. Could it be, oh, Satan?! I mean, thermal?!
This is particularly ironic since the article referred to the discovery of light pressure earlier. Everyone knows those little bulbs with white and black fans that "demonstrate" this effect. What most people don't know is that it isn't a perfect vacuum in there and, gosh, the dark side gets slightly hotter than the white side. That means the gas heats up on one side, expanding, you know the rest. IIRC they spin leading with the white side. It should be the other way since you have twice as much momentum transfer to reflect light (white) than to simply absorb it (black).
(BTW, I agree 100% with everyone who's pointing out that the walls of the cavity account for the rest of 'thrust' and that the device will just sit there driving up your power bill.)
For every complex problem there is an answer that is clear, simple, and wrong. -- H L Mencken
My understanding of the basic math suggests that a photon-creating drive will tend to be inefficient. The amount of light energy necessary to get a significant amount of momentum is simply enormous, which is why you don't feel flashlights, even very bright ones, pushing backwards perceptably when you turn them on.
The article makes this guys thing sound like some kind of perpetual motion machine limited only by his ability to build a perfecct cavity. I haven't read his paper yet, but I'm skeptical of his ability to get more momentum out of a photon that the photon itself contains, unless he has some other reaction mass. If his photons are transfering momentum to the cavity on each continually, then the photons should be losing momentum as they do so (in the form of dopler shift?), and therefore the total momentum gained should be no greater than merely shining a flashlight backwards.
Or at least, that's my understanding. I Am Not A Physicist.
. . .from TFA it sounds like this guy is applying good scientific procedures to his work. . .
The proof that his working model, well, works, are measurements taken at the limit of the ability to measure the effect. This is not good scientific procedure. You are right not to hold your breath.
KFG
Tue Sep 19 17:56:42 PDT 2006
Russell McMahon wrote:
I don't know that a reactionless drive can't work - although I don't know how to build one
Without having gone into it in detail, his math seems okay up to eq 6 (when he is quoting well-known math), but thereafter he veers into the realms of error and fantasy.
Eqation 7 is incorrect in so far as it purports to describe the total forces on the waveguide - while it does correctly describe the sum of the forces on the ends of the waveguide, it does not take into account the forces produced on the sides of the tapered waveguide.*
All by itself that is enough to blow the conclusions of the paper completely out of the water. It is simply wrong. It doesn't work. You can stop reading here.
Now we get into the rather more dubious portion of the paper.
Eq. 8 is also in error - it is based on the incorrect statement "...as the two forces Fg1 and Fg2 are dependent upon the velocities vg1 and vg2, the thrust T should be calculated according to Einsteins law of addition of velocities." - but the conclusion does not follow, and use of Einstein's equation is inappropriate. There is no real-world summing of velocities, it is a mathematical trick (and there is an error int the math too). The ends of the waveguide are stationary relative to each other.
That is an elementary schoolboy (or snake-oil salesman's) mistake.
There are several other obvious mistakes in the paper, and he frequently states as fact things that are unjustified and on occasion untrue. There are also parts of it which seem to be meaningless.
For example, this is also incorrect: "The second effect is that as the beam velocities are not directly dependent on any velocity of the waveguide, the beam and waveguide form an open system."
The conclusion does not follow.
This is actually very confused - I don't think he even knows what he is saying. Relativity theory does not (directly) come into it at all.
I stopped looking for more errors about here.
Snake oil or error?
There was some mention of licencing the technology, but as it is in the UK patenting it here would be impossible - it is, after all, a perpetual motion machine (or it would be if Q approached infinity, which there seems no theoretical reason to suppose impossible), and you cannot patent a perpetual motion machine in the UK.
Even if it worked.
The question of how he got a grant is still
To the DTI, NASA etc: Please can I have half his grant for pointing out his mistakes? I promise I will use it do space r+d.
*Of course if you want to consider the waveguide as two pieces, forces on the tapered walls do not affect the result - but the math in eq7 would be wrong if you are looking at it that way, eg the lambda-g1 and lambda_g2 figures are for the ends of the waveguide, not the middle.
I think he first went wrong in his mind here - in fig 2.4 there is a vertical line in the middle of the diagram, implying that he was looking at the waveguide as two pieces, rather than as two ends and a tapered middle. You can of course look at it in either way, but in his analysis (even before we get into the error-full "relativity" stuff) he is trying to do both at once, and that will and has lead to error.
--
Peter Fairbrother
--a different AC
Potentially, it could pack the punch of a rocket in a box the size of a suitcase.
That seals it. The terrerists could use this, so we must ban all further research!
By the way, this engine would violate conservation of momentum, and is thus incredibly dubious. On top of that, the "working" prototype was measured to generate an incredibly tiny force, a measurement which was given without error bars in the only numbers I've seen, so he's probably just measured his noise floor. It has never been published in a peer reviewed journal. Because of this article, John Baez has posted an open letter from Greg Egan to the editors of New Scientist, which includes gems like "I really was gobsmacked by the level of scientific illiteracy in the article".
In other words, reader beware. Crackpots abound.
Simple example
Case 1: (Ion engine)
If you tossed something where there is no gravity (space) and it is a vacuum (you have nothing to push against (the earth)) you will gain the momentum that the object you tossed gained. (Conservation of energy thought you might have lost some due to the effort of the toss.)
Case 2: (This engine)
If you now build a box in space and toss something inside of it (dose not mater if it is a vacuum or not) you are going to go one way and the object is going to go the other. Now you will both hit the walls and transfer some energy to the box and you will probably bounce around a bit to. The thing is the over all energy transferred is zero. The box will vibrate, but will not really go anywhere.
So what dose this mean? For you to gain momentum you must expel something in the opposite direction you want to go. Rocks and jets don't push they throw partials out.
Now yes there will be heat lose and other energy but in these cases that is negotiable though in this engine could make a difference (heat is just another form of radiation). So assuming that the microwaves end up as heat and all that goes out the wide end of the tube instead of randomly dispersed. It could work.
This is the best I can do with out giving math examples if someone can do better please do.
Sorry I did not answer your question I just ended up saying that the bouncing should cause the engine not to work. Hummm... Oh well...
I've always thought "New Scientist" was mostly junk. If I see something on /. that is scientifically questionable it is usually from "New Scientist". I thought the name even sold itself as being on the fringe. "New Scientist" being a scientist working on new stuff on the fringe that may or may not be valid.
I'm pretty sure that the Phantom gaming console has that business model patented...
Nephilium
It's not enough to be able to pick up a sword. You have to know which end to poke into the enemy. -- (Terry Pratchett, Lords and Ladies)
It's always been a pseudo-scientific journal.
Perhaps we can save it from itself, and recreate it as something which doesn't promote every crank making metaphysical claims.
I'm very surprised that this is being reported on. There's nothing to this.
What's probably happening is that the microwaves are leaking out heating up one side of the thruster more than the other causing the air on that side to warm up and become bouyant which is whats creating the apparent thrust. I could make a lot more thrust with a 700 Watt fan than 88 millinewtons.
I'm starting to dispair over the state of science in this so called modern world when I see articles like this. Maybe next we could have an argument over whether sidereal or tropical based astrology is more accurate at predicting the future.
microwaves are interesting and stuff
but why don't we just use nuclear bombs for propellant.
After all the first man-made object that went into space was that giant manhold cover that the US was using in 1955 for underground nuclear weapons testing
"..much of it bemoaning the abysmal standards to which New Scientist has slipped. "
well.ets be honest here, scientist always have a habit of doing that when something they don't agree with is published.
". Not only does the article suggest that this "drive" violates conservation of momentum,"
There is nothing in Relativity that says this someone can't exploit the difference in frames.
Do I have my doubts? certianly, and strong ones at that. strangly, the article doesn't ring the BS meter.
Having a working prototype(alledgedly) is a good start. His credtionals seem good.
Agreeing to independent review is also good. Most people BSing about this stuff say things like 'the scientific community is keeping me down.' and won't allow third parties to review the work unless they are paid money in advance.
The Kruger Dunning explains most post on
It was a really bad article. It was clearly a dodgy claim and you would think they would have an expert in the area totally vet the article, but alas no.
/ YaBB.pl?num=1157719780/0)
There are some other worrying things in the article. For example, the author says...
What of the impact of such a device? On my journey home I have plenty of time to speculate. No need for wheels, no friction.
Yet it is precisely the friction between the wheels and road which make a car go forward. Friction with the car wheels is not bad, you need it. Friction with the air is bad, but not the wheels.
If I had do the EM Drive story, a story which sounds highly suspect, I would have looked at some critiques of similar schemes. Within a few minutes of searching I found similar "Reaction-less Drive" schemes which all turned out to be Oscillation drives. It's the same phenomena as when you move across the room in a swivel chair (without touching the floor) by shifting your body-weight around. When you do that you are exploiting the non-linear nature of friction between surfaces. A similar thing can happen with these reaction-less drives interacting with air, water or other surfaces. So it's quite possible that a prototype drive would appear to work. So I would have asked for some kind of proof that this was not an oscillation drive.
Another issue is that it's not clear that this Em Drive prototype has been tested in a vacuum. In one of the other articles on it, it says that the thrust only reaches the maximum after a few seconds. Now that sounds much more like a mechanical oscillation effect (building up to maximum amplitude) than a photon/microwave effect.
Some of what I have said here is re-posted from a discussion I had on the Elmurst Solutions Science forums. (http://www.elmhurstsolutions.co.uk/cgi-bin/yabb2
The latest New Scientist has an article about...
The New Scientist is a weekly publication. This article is from the Sept. 9th edition. In what way does this make it 'the latest', given that two subsequent editions (16th, 23rd) have been published?
Hey, guys, while you are at it, I have this idea for an infinate power source! You see, you take an electric motor and you connect the axel to a lot of generators! You see one of the generators would power the motor and you could run the whole world on as many other generators as you tacked on! Use it! My gift to humanity! ;P
Seriously, all this guy is missing is the smoke.
It doesn't matter that one end of the frickin copper has a bigger diameter than the other, the walls are not normal to the surfaces and will absorb any force from the collisions with the photons as well. The 2 normal forces would be equal in each direction and thus would be 0 net force for the system. The only thing that would happen is the can would have a tendency to expand a very small amount more that what could be accounted for by thermal expansion alone at best.
Think about it. Otherwise conical objects would have a tendancy to rocket around on their own because of air pressure.
You seem to be under the impression that the poor science somehow disqualifies it from consideration by Slashdot editors. I think there's a flaw in your underlying assumptions. Perhaps you'd like to spell some of them out, and we could work together to find which assumptions are erroneous?
Ce n'est pas un vrai mouvement de robot!
Even if this did have a chance of working... I would love to be the one who walks on the sidewalk while the "floating cars" send out their microwaves to cook me...
but that's the point, anything that spits out photons (microwave or any other frequency), can only be a photon drive, and bouncing the photons internally accomplishes absolutely nothing, it doesn't make more microwaves nor does it increase microwave energy (and I'd like to poke the writer of that article in the eyes just for speaking of near-light speed of microwaves). In short, this "invention" is a load of crap and a waste of time based on a lack of understanding of EM.
My first reaction was: "you must be new here..."
No folly is more costly than the folly of intolerant idealism. - Winston Churchill
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.
Erotic is when you use a feather. Exotic is when you use the whole chicken.
RTFA
I would have to surmise that whatever thrust he gets against the wide end will be offset against the force not only on the narrow end, but also against the oblique walls of the chamber!
-jcr
The only title of honor that a tyrant can grant is "Enemy of the State."
He actually made the Infinite Improbability Drive! He just left a Brownian motion producer in the microwave when he turned it on creating a Really Hot cup of tea.
It's a bit harder to drive your car into the side of a highrise buidling.
How, exactly? Do the highrises where you live float above the surface the cars drive on?
I can accept that controlling a craft in three dimensions is more complicated than doing it in two, but I don't see stationary buildings as a greater threat than they already are.
The ground itself, though, you have to learn to watch out for.
The US free market: two halves of a government-granted duopoly are free to set the market price.
At the bottom of the "official" web site, emdrive.com, there's the contact info, that consists solely of an AOL email address.
Confidence builder if I ever saw one.
"Win treats sysadmins better than users. Mac treats users better than sysadmins. Linux treats everyone like sysadmins."
Yeah. Get the prototype tested. Evidence beats theory any day, well almost.
Bitter and proud of it.
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Does this take into account the several inches of lead required on all vehicle bodies to keep the radiation out?
Yet it is precisely the friction between the wheels and road which make a car go forward. Friction with the car wheels is not bad, you need it. Friction with the air is bad, but not the wheels.
I thought it was the exhaust coming out of the back that propelled the car forward.. I mean, if electromagnetic radiation can propel something forward surely gaseos exhaust can?
// MD_Update(&m,buf,j);
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.
Oh, there have been any number of people who have put forward various intertialess drives for independant review. You are right, there is a difference between the honest crackpot and the snake oil salesman (thank god, or I might be in real trouble myself), but sometimes tests actually just waste time and resources when the theoretical failures can be defined without actual test.
And my point was that he hasn't actually built anything legitimately testable in a lab yet. The forces are so small that we'll need to fly the puppy to judge it at all. This is different from the solar sail which already know could work by theory and ground based test.
I can build you three or four mechanical variations on the theme that will even stand up to review in the sense that they seem to work perfectly well in the lab, much better than this one does because they'll actually scoot across the airtable, but the reason why they won't work in space are well enough understood that no one is going to waste a bird to send one up.
It's perfectly possible to become an honest crackpot by simply getting a bit of the equations wrong and have that failure perfectly obvious to other people.
KFG
Comment removed based on user account deletion
Is there no-one with a modicum of common sense vetting slashdot stories? Please, please, spare us these ludicrous something-for-nothing 'physics' stories! But then, maybe I'm wasting my breath. I'm beginning to think that they are put forth with full knowledge, just so we can all get worked up over the silliness and generate thousands of posts. Hmm. I think I'll start charting their occurrence. I'll bet there is a slashdot formula, much like a Star Trek: TOS episode formula, calling for a certain number of blatantly silly pseudo-physics (or provably impossible data compression) stories per week.
Those who would give up essential liberty to purchase a little temporary safety, deserve neither liberty nor safety.
Maybe they are just borrowing the momentum from a future frame of reference.
...i'm addicted to free pr0n!
After reading the critiques here and at some U of Texas physics site, the best I can figure is that this setup may be plausible as weak thruster, and is plausible as a strong levitator.
If you take a couple of magnets and place like poles together, they push away from each other until they're too far away to push anymore. Yet no material has been exchanged between them, and no particles have been thrown out one and hit the other.
That's the best analogy I can draw- this is like setting up a repulsive magnetic field without magnets. The precise physics are above my pay grade, but viewing it in this manner doesn't appear to violate any laws of physics.
(For those of you who didn't RTFA, it states that the thrust dissapears if the 'engine' actually moves. I think I might have had that bit in my original submission, and Zonk cut it out.)
Alcohol, Tobacco and Firearms should be the name of a store, not a government agency.
Hm.. it looks like there isn't a Wikipedia article on Roger Shawyer, but there is an article on his "EmDrive":
http://en.wikipedia.org/wiki/EmDrive
It's a fairly interesting read, and even though it's still rough in spots it's certainly better-informed than the scientifically-confused New Scientist piece linked in the submission. I particularly suggest reading through the analysis of Shawyer's claims.
While the idea sounds interesting, and I'm sure it would reduce drag significantly, I don't really like the idea of plummiting to the ground like a rock if there's an electrical failure. Hell, you wouldn't even need that - just a thrust imbalance would do the trick.
The ability to glide to a landing is sort of a big deal for me.
Who is John Galt?
- One is that you're trying to develop something really cool, and you're raising money to let you do that
- The other is that you want to have a company that pays you a lot, so you're trying to develop something cool as a hook to get investors to give you money.
It wasn't just during the Boom, and it wasn't just Internet projects, but back when you could go to Menlo Park and shake a tree and a venture capitalist would fall out, both kinds of projects were quite popular and ran like well-oiled snakes.It sounds like the inventor *might* have the physics to be able to develop a little drive for steering spacecraft, which is a much much smaller problem than launching them, and having steering drives that ran for a long time on electricity without physical fuel could be really useful. I can't tell for sure from the article if there's really an existing prototype that generates thrust, or if it's just physics on paper. The launch engines / flying cars / etc. sounds like Pure Hype, not only without a prototype but without even the basic physics or engineering work that says that the thing can not only generate thrust, but can generate *enough* thrust to lift its weight and the weight of it's power feeds. (For steering engines that's not necessary - the big hulking chemical engine has enough power to lift the thing, and your Magic Engine only needs to be able to nudge the ship around slowly for a long time, which is much simpler.
Bill Stewart
New Fast-Compression-only CPR http://preview.tinyurl.com/dy575ks
cover my private parts while standing in front of it? You know, so I can have children in the future. :)
The latest New Scientist has an article about an engine that exploits relativity and microwaves to generate thrust.
Ok, so when can we expect the patch to protect users from the exploit?
"Beware of he who would deny you access to information, for in his heart he dreams himself your master."
So I could be wrong, but, IIRC, momentum of EM radiation p=E/c. Therefore, Force = Power/c. 1kwatt/c = 3.3 millinewton. So, unless I'm mistaken, 3.3 millinewton is the theoretical maximum thrust you can get from 1kwatt of power (assuming 100% efficiency). The entire shtick about oscilations sounds like an attempt (apparently successful) to confuse government dumbasses with purse strings. You can oscilate microwaves all you want but until you shoot them out into space, you don't get any momentum out of them.
Ok, after reading the article and the PDF "theory paper" I'm curious as to why the data from his 450 or so tests wasn't published along with the paper? Not saying that it doesn't work, but being in an academic environment and seeing scores of published engineering works, I'm a bit suspicious of someone making a claim like this without publishing the data. Sure, the mathematics might be clean (not a mathematician nor an engineer personally, so I can't really say), but where's the data? The intellectual property portion he's published in the form of the mathematics and schematics of the device (although also crude), so trade secrecy is certainly not at stake. Bottom line, "Where's the beef?"
Did anyone else immediately think "Infinite Improbability Drive" when they read the blurb? It also had no moving parts -- just a bistro!
I am not left-handed, either!
That's the, um, string nature of reality acting up again. Should be worked out by the next prototype, after my next grant cheque.
I have freaks! I did something right...
Yet it is precisely the friction between the wheels and road which make a car go forward. Friction with the car wheels is not bad, you need it. Friction with the air is bad, but not the wheels.
We could do without the friction on the wheels for propultion without much difficulty. Stopping is entirely another matter...
No, that is not true. Scientists actually have a habit of looking at new ideas - they do that every day - and doing their best to evaluate the new ideas using a suite of rational and emperical methods. Just like in Open Source, a great new idea might occassionally be missed, but history shows that the scientific consensus is amazingly good at converging on what can be seen in hindsight to be the 'right' understanding.
A fair comment for you to make, relativity is a difficult subject and claims based on its theories are not easily tested using common sense. Unfortunately those who understand relativity know that the statement is completely wrong. Others have linked already to the views of a wide range of scientists with a better understanding of relativity than I.
In theory, there's no difference between theory and practice; in practice there is.
When you asked the scientistic community in the hundreds of years ago if flight would be possible, they'd only laugh at you.
Coaches moving at high speeds without horses? Ridiculous!
Visiting other "planets"? With a special cannonball perhaps.
I'm not an expert in this area - as I suppose most of slashdot readers aren't - but unlike most I won't just call him a "Crackpot" based on some bias. He seems work to scientifically, though it sounds unlikely, if his protype really worked as he claimed he has shown some interesting results. Personally I won't touch relativity with a ten-foot-pole (not matter the speed of the pole or the frame of reference) - we love to pretend to live in a nice, orderly universe without relativity and quantum effects, but in reality those things happen all the time, they just have too small effects to be really noticed. But they exists, and if they are exploited correctly things might be done that are "impossible" for our normal world view.
+++ MELON MELON MELON +++ Out of Cheese Error +++ redo from start +++
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.
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
Although seemingly unlikely, I couldn't convince myself from the article that it was impossible so I took a look at the paper. After looking at equation (1) I already suspect the guy doesn't know what he's talking about. He uses the group velocity of microwaves in the Lorentz equation, but the Lorentz equation only makes sense for charged particles, not light. That "q" in the equation in charge, so I guess he's claiming light is a charged particle?
His magic box to provide upward lift & a fan to provide forward motion.
Removing rolling friction isn't a bad thing, but then you have a ground effect vehicle and have to design accordingly.
If his idea ever pans out, I think the best compromise would be an electric motor + wheels for the initial acceleration, then pull up the wheels and use the electric motor to power a fan.
Good luck in a cross wind though.
[Fuck Beta]
o0t!
Well, just thinking about something: if the path of the waves isn't exactly parallel to the axis of the waveguide, so that the waves/particles are bouncing off of the walls every so often on their way down, then although the particle may have a velocity equal to c, the component of its velocity in the direction parallel to the waveguide will be slightly less than c.
So it might be a true statement from that perspective. Only if the wave is going directly down the waveguide's axis, so that all of its velocity is in that direction, would the speed "at which it is moving down the waveguide" be equal to the speed of light. In most cases, the speed in that direction would be slightly less.
"Ladies and gentlemen, my killbot features Lotus Notes and a machine gun. It is the finest available."
Horn.
... (=big-small) to the left.
Small end to the left, big end to the right. Bouncing stuff inna middle (photons in this case).
Force onna left end - small, to the left. Right end, big, to the right.
Force onna walls - radial component cancels out due to symmetry. Axial component
net force right: big
net force left: small + (big-small) = big
net force = zero
next
But even if this is the reporter's goof, confusing acceleration and velocity, the inventor claims that the device would work better for hovering (presumably in Earth's gravity) instead of accelerating. This shows that the inventor does not understand relativity or basic physics. If his device could make a car hover then it could also accelerate the car at 1 G.
According to the physics fact book, a 2001 Jaguar KX8 and a 2000 Mitsubishi Eclipse can each accelerate at 3.8 m/s^2 which is less than 1/2 G.
Since the inventor does not understand one of the simplest applications of relativity (gravity is the same as acceleration) I do not trust his calculations that claim some relativistic effect is giving him a force that will violate the conservation of momentum and energy.
We don't see the world as it is, we see it as we are.
-- Anais Nin
We're fucking tired of free energy and hovercar posts! Give us real inventions to drool over!
Create a new kind of license for flying cars, one that requires more training and stricter tests.
You already need a different license than a regular car license if you want to drive busses or trucks or whatever so the same should apply to flying cars.
Basicly, if you want to fly a flying car, you have to demonstrate that you can fly a flying car without crashing it.
Doesn't take much to make a turbo version of this microwave drive, simply add eggs!
Carbon based humanoid in training.
Not without ditching wheels altogether. And with wheels
...with no moving parts. Take a tube, open at one end, pack full of solid rocket fuel. Aim the open end away from your destination, and light.
As I can tell from his paper and the article, the thrust generated is very very small. This is fantastic for spacecraft where you have a lot of time available for acceleration, but we won't be seeing flying cars any time soon. :-(
If it works it is a FANTASTIC technology, however, the writers of the article had to hype it beyond reason to get the attention of ordinary people.
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.
--
Mad science! Robots! Underwear! Cute girls! Full comic online! http://www.girlgeniusonline.com/
That's the best post on this page.
All right, so you're a theorist. I'm an experimentalist. I can accept that it may violate the laws of physics as we know them. That would only mean that we need to rethink a couple of things. (Long term that's a given anyway.) All I want to see is a working model verified by a third party. Show me that and I'll accept that we need to change a few theories. After all, it's not like it hasn't happened before. (like with Copernicus, then Gallileo, then Newton, then Maxwell, then Einstien, then with Born and friends, then with... Well, you get the idea.) Meanwhile, all the stunts of 'respected scientists' starting a drive to 'save' a magazine are just stunts, probably part of jockying for funding. They don't want the competition in a set government grant pie. Let it pass. It's (the criticism) just meaningless drivel. Like Cold Fusion, this idea will stand or fall based on whether it can be reproduced or not. If it can, then all the 'proof' that it can't work will be like the mathematical proof that the Wright brothers couldn't fly. Bumble Bees can't fly either, in theory (old theory by the way). Stupid bees are too dumb to know that, so they fly anyway. Maybe this guy is like the bee. Let him either fly or fall. he doesn't need us to do either.
Everybody knows 3 people with my name.
(If that sounds dubious, you can see why I'm skeptical of the premise.)
I realize that the parent post is supposed to be a joke, but the paper indicates that the thrust measurements were not done in vacuum. The heating of the water vapor in the air would likely be significant (since the microwave oven magnetron frequency was chosen to be that of the resonant frequency of H2O). The resulting steam might propel the 'engine' and skew any measured thrust results.
Sorry for being so skeptical. Also, the efficiency of this thing at its theroetical limit is something like 0.03%. Any spacecraft using it had better have a BIG on-board nuclear power source (RTG).
Shawyer has decades of experience designing systems in the space industry, gotten £250,000 to research his theories, been reviewed by independent experts from UK's Department of Trade and Industry, and may well deploy this system in a satelite within two years.
Most of the high mod comments I've seen so far boil down to, "He's a fake!"
Well...what have you skeptics done lately?
Cheap, non polluting power engines that never wear out AND power my flying car?
*That's when I realized this was all a simulation*
I don't know the meaning of the word 'don't' - J
His invention seems bogus - the crux where resonating the microwaves produce more thrust than just pointing them seems like he's getting both relativity and Newton wrong.
But what about the simple case of conservation of momentum in a regular laser? If I fire a laser in space, lots of photons with tiny, but real mass go flying in one direction, all lined up very consistently along one force vector at near the speed of light. That seems like some momentum transferred in one direction. Won't the laser move in the opposite direction? Accelerating its much greater mass at a smaller rate, but still a cumulative rate?
Lasers can convert stored energy at a very high efficiency. They don't have to heat up or mechanically vibrate much, compared to other transducers. And they direct the energy in on narrow direction so practically all of its force vector is summing in one direction. And microchip laser arrays mean lots of photons can be lased by a relatively small mass of laser.
If that actually works, how about positioning another projectile in the path of the beam? Won't the same amount of momentum that's pushing the laser also push the target in the opposite direction? Two projectiles moving apart away from their starting point, conserving momentum to zero but pushing both away into space. Make both into lasers with "solar" sails to catch each others' beams, and they're moving apart with double the momentum.
This one doesn't harness relativity, just Newton's re/action law, and something like the photoelectric effect. So Einstein gets some credit, but in devices already cheap and proven. If it actually works.
--
make install -not war
More advanced versions might allow cars to lift from the ground and hover.
Meet George Jetson!
~~ Behold the flying cow with a rail gun! ~~
Then you and your investors could start publicly referring to the invention in a grandiose code-word, like "IT", and make sweeping claims like it's going to change the way we design cities. That way, when you finally reveal it, no matter how impressive it actually is, people will be disappointed that their lives weren't instantly changed overnight.
This apparatus is a Radiometer. And it's not really working by the expansion of gas on 'hotter black side' -- the pressure throughout is essentially constant. The effect is caused by the movement of the rareified gas at the edges of the vein due to the temperature gradient.
Better explanation (and historical context): http://math.ucr.edu/home/baez/physics/General/Lig
When the apparatus is refined, by using a much better vacuum, suspending the 'blades' in a way with less resistance, and coating them in inert material the light pressure can be observed directly -- it will spin with the dark side leading. The link above says this was first achieved in 1901.
Read Heinlein's 1953 Revolt in 2100, now more than ever.
It's only a closed system if you think in terms of eletro-magnetics. Assuming the prototype works to any degree, what if he's found an electro-gravitational effect? Yes, I'm reaching a bit here, but gravitational effects aren't limited to an enclosure... or maybe even our dimensions... so it wouldn't be a closed system.
Forget thrust, drag, lift and weight. Airplanes fly because of money.
Jet-powered supercooler.
Think a little harder.
Ever tried to accelerate in the snow?
Acceleration and deceleration essentially work via the same friction between the tires and road.
Unfortunately logic does not work like that. Exploiting relativistic effects will not allow you to violate 4-momentum conservation, which is a conserved invariant in relativity. 4-momentum is conserved in every inertial reference frame. I don't care what frame you switch to, you can't make 1=0.
Well, photons do have momentum, and that momentum is proportional to their wavelength. If their wavelength increases, they lose momentum that can be transferred to something else.
If that is the case, then his derivation from known theories is completely wrong. In which case, even he doesn't know how his magic device works.
Actually, special relativity covers this pretty well.
The idea that the internal forces will balance is Newtonian. If we have a ping-pong ball bouncing back and forth in a horn-shaped chamber, we have two cases to consider: when the ball is close to the center, it bounces from one flat end to the other and the force of each bounce balances the force of the bounce at the opposite end. When the ball is close to the edge, it bounces from the large flat side and then hits a wall. The force of the impact with the wall transfers some energy from the ball to the chamber, and slows the ball down slightly. The energy transferred to the chamber has one component perpendicular to the chamber's axis, and that component moves the chamber sideways a little bit. There's also a component that's parallel to the chamber's axis, and that component precisely matches the loss of force when the ball hits the small flat side moving at a slightly lower speed.
Problem is, we're talking about photons. They don't have the option of slowing down.
When a photon loses energy by reflecting off the chamber wall, it can't lose speed, so it loses mass. The energy gained by the chamber wall is translated into heat, not linear motion. When the photon gets to the small end of the chamber, it's still moving at the speed of light, but has less effective mass, so it imparts less energy to the chamber with that reflection.
The energy is conserved properly, even if the traditional notion of Newtonian momentum isn't, and it's well established that relativistic mechanics don't preserve the Newtonian concepts of mass or momentum.
It's also worth noting that this isn't a perpetual motion machine. As soon as the whole system moves, the photons inside the chamber lose their energy and have to be re-excited.
But the thing that I think most people don't really think about is that an object isn't really ever "alone" out there. There are incredibly massive forces at play all over the place as far as I can see. The Earth zooms around the Sun with a huge connection keeping it in orbit. The Sun has a relationship like that to the galactic core, and so on out to larger scales. I'm no scientist of course, but I can certainly see for instance that a device similar to what is described in the article could interact with the Earth itself. As in, the Earth is the giant gravimagnetic object and you circulate power in this object, which creates a powerful repulsive force. It doesn't seem much different to me than the coil and magnet example I gave earlier.
Anyway, I'm sure the explanation this guy is giving is balogna, but that's not to say that what he's doing doesn't have a tangible interaction with Earth's gravitational or magnetic field for other reasons. Or maybe it is. You tell me ;-)
I have a swimming pool with a tapered bottom. The force on the wall at the deep end is much greater than the force at the shallow end. I drive it around the city all the time. As soon as I can figure out how to turn it upright, I'll be giving free flights to slashdotters and Jerry's Kids.
Where can I locate the anonymous "Air Force visitor" who always gets trotted out as "proof" the inventor isn't a crackpot?
Here is an old article from 2002 with pictures. You would think in 4 years he would have already proven this... http://www.shelleys.demon.co.uk/fdec02em.htm
But look at what Shawyer has actually provides: he says he has a working model, but what he publishes is theory about why his device should work, not a detailed protocol of his experiments. At this point it's his theory against "establishment" theory, and the establishment theory is the one that's got all the published experimental evidence.
The New Scientist article makes much of the fact that major corporations are looking at his work, presumably to give us confidence that competent people are reviewing his work. I am put in mind though of several major electronics firms that embarassed themselves investing in a plan to send video over plain old phone lines. See for example: VisionTek
So assuming that New Scientist fail to noticeably pull their socks up, what should I replace my New Scientist subscription with when it expires?
Scientific American? Annals of Irreproducible Research?
Weight : 9 kilograms Thrust : 88 milinewtons Quite better than the european ion engine but still awfully far away from being able to lift its own weight (in earth gravity field). And I don't even speak about the weight of a car or a plane. Still an interesting effect though, but the reporter obviously overhyped it. I'll reconsider when it can thrust its own weight, that would only be a x1000 factor...
The Wise adapts himself to the world. The Fool adapts the world to himself. Therefore, all progress depends on the Fool.
If you look at the articles today about 95% of them are not really science articles, more social science or political. For example there are articles on animal testing, an editorial about the possibility of bird flu, a huge section on religious fundamentalism, and an eco-law special in the latest 8/2005.
Its seems they got a bunch of writers from the Guardian and let them loose, at the same time putting a tabloid womens magazine editor in charge: (those terrorists are out to get us: "where holy writ must hold no sway"; a psychology special: "the empathetic ape" both 8/2005)
Its worse scientific content than Popular Mechanics now I think. Years ago there was a maths article per magazine. That held out for ages and made it worth picking up since its hard to spin maths. That doesn't exist any more. There might occasionally be good articles but I don't see them because I can't stand trawling through the rubbish.
Having a look at the most recent one to back up my post confirmed my worst opinion. I started off being tongue in cheek but after looking through it for examples, things are worse than I thought! If you're looking for a serious scientific magazine forget it. In fact a big chunk of both Nature and Science are also going like this. (Nature is terrible, seems to be a UK thing). These mags have gone from science to science wankery. Articles about "the french oyster ban mystery" podcasts and wifi are not scientific articles, they are pap journalism.
Same AC, just to follow up - the date I gave, 8/2005 is correct, but its obviously not the latest. someone must have grabbed it off the shelves. You can tell I don't follow them very hard.
Those examples are a year old. So if a year ago it was this bad, not going to waste more time trying to find the current one.
I hate people sit around and pronounce that they KNOW that something without even trying it.
(Brain calcification has set in.)
If you read the article it says that he has been documenting this whole thing very carefully.
I don't know enough about physics to know if this is posssible or not, but if he has documented it, someone else should be able to build one and see if it does what he says it does.
Every wrong attempt discarded is a step forward - T. Edison
Bogus or not, don't we have the technology now for a global ocean-based nanotech entropy engine to suck the extra heat out of the atmosphere, solve our planets heating problems and generate energy at the same time? SF writers have been theorizing about this since the 50's.
I think the key part of your debate falls down with discounting things by predicting theoretical failures before a test is made.
Theory always alters to fit the observed facts. And every now and then, something pops out of the hat that changes everything.
It may be possible to be an honest crackpot by getting the equations wrong, and have that failure obvious to everyone else.. It's also possible to find something that works despite what the equations say..
That's called advancing science..
Wrong or right though, it'll be interesting to see how it pans out..
..nuff said
"Fix it"
> Shawyer proposed that the company develop his idea. "I was told
> in no uncertain terms to drop it," he says. "This came from the very top."
Bzzzzt! Baloney detector alert! Baloney detector alert!
> What's crucial here is the Q-value of the cavity
What does how much girls 13-29 think the cavity "is their friend" have to do with this?
(-1: Post disagrees with my already-settled worldview) is not a valid mod option.
The speed of light is c. The speed of light in air is slightly lower. This isn't a contradiction because the light rtavels between absorbtion/radiation actions at the speed of light in a vacuum (c) but the absorbtion/radiation takes a little while where the light is (effectively) not moving.
So you're wrong and the article is not clear.
I know of no theory, even including the magical "relativistic" physics that allow for or predict unbalanced forces in a closed system.
This guy is a crackpot, and New Scientist is irresponsible to have published it without the most basic checking of whether his ideas make any sense or not.
But there are physical theories in which forces are unbalanced, at least in the sense that Newton's third law is not true. In particular, take classical electromagnetism.
Suppose you have a point charge 'A' which is moving forward. Directly ahead of it let there be a point charge 'B' which is moving perpendicular to the velocity of 'A' (i.e. moving so as to "cross the T").
From the Biot-Savart law, we know that 'B' generates a magnetic field at the location of 'A'. By the same law, 'A' does not make a magnetic field at 'B'.
The electric fields of 'A' and 'B' contribute equal and opposite forces. In addition, as described by the Lorentz force law, 'A' experiences a force due to the magnetic field from 'B'. But 'B' does not have any corresponding force acting on it.
But this would also seem to mean that the total momentum of the system is not conserved! Fortunately, we can keep conservation of momentum, if we expand our idea of 'momentum' to include also a certain quantity described by the electromagnetic field. So even though we lost the mechanical notion of 'even and opposite reactions', we can still make use of conservation of momentum, which is just as good (and more true) anyway.
If you pre-order Duke Nukem Forever now, you'll get a free relativistic microwave flying car when the game ships.... ;-)
"'I pass the test,' she said. 'I will diminish, and go into the West, and remain Galadriel.'"
- JRR Tolkien.
But this seems to me to be unlikely. Either the microwaves are in phase, in which case you have a maser and the pressure will be equal regardless of the shape of the waveguide, or they're not in phase, in which case destructive interference is going to result in less pressure on the wide wall, per unit, but the same amount total, regardless of the shape of the wave guide.
This looks a lot more like one of those things where the 'thrust' is within the error of the experiment and nobody else can reproduce it than a new propulsion mechanism. He may not even be a con artist, just bad scientist. See "Hafnium Triggering"
See what peer review says. I could be wrong.
Pug
An Invisible Entity of Vast Power whose existence must be taken on faith alone: Liberal Media
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.
Real Daleks don't climb stairs - they level the building.
Surprisingly, New Scientist used to be a great magazine.
I'm not convinced. I recall seeing a letter written by R. A. Fisher in the 1950s in which he lit into New Scientist pretty good.
certainly, the "old" New Scientist would never have allowed an article to be published which suggested that conservation of momentum can be overcome by messing around with frames of reference.
That may be true. New Scientist may never have been great, but I doubt it was in former times so bad as it is now.
The chamber gets very hot due to microwave heating. It's larger at one end that the other. It heats up the air, which becomes less dense. There is more less-dense air at the large end than the smaller, so it "sucks" itself round.
Can I have a banana?
Stick Men
... and make trains, planes and automobiles obsolete ...
Obsolete??? Nooooo...I LOVE that movie!
Slashdot: News for Crackpots, members of the Flat Earth Society, and proponents of Gene Ray's "Time Cube". Stuff that really, really matters.
> "The prototype generated 16 millinewtons of thrust, using 1 kilowatt"
Is it me or is that a truly microscopic amount of thrust for that much input power?
No such negative thoughts ;-0
Pitty it doesn't make it through Feynman's criterium, though [http://en.wikipedia.org/wiki/Polywater and http://www.hyle.org/journal/issues/8-1/bauer.htm]
Just to let you know, momentum is conserved under relativistic conditions, it is just divided by a factor of gamma (the sqaure root of: 1-(u/c)^2 where u the relativistic velocity and c is the speed of light.
Meanwhile, all the stunts of 'respected scientists' starting a drive to 'save' a magazine are just stunts, probably part of jockying for funding. They don't want the competition in a set government grant pie.
That's an asinine statement. Neither Roger Shawyer nor New Scientist are competing with any of these people for grants, and even if they were, what New Scientist does or does not publish has absolutely no influence on funding decision. You are completely ignorant of how science is actually done.
As it happens, I know one of the scientists in question personally (John Baez, actually a mathematician, as is Peter Woit). Greg Egan isn't a professional scientist at all; he's a science fiction author. The people supporting the "Save New Scientist" campaign are not doing work in any way related to Shawyer's ridiculous EM Drive. Rather, they are all science popularizers (check out Baez and Woit's blogs as well as Egan's science essays in SF magazines). They are tired of trying to undo the damage to the lay public being done by New Scientist; their audience can't tell when New Scientist is reporting on real science, highly speculative theories, or pure crap.
If it can, then all the 'proof' that it can't work will be like the mathematical proof that the Wright brothers couldn't fly. Bumble Bees can't fly either, in theory (old theory by the way).
Those are both urban legends to one extent or another. Nobody ever had a mathematical proof that the Wright brothers couldn't fly. There were some arguments that other designs using particular materials couldn't fly. As for the bumblebee story, it's probably apocryphal, and nobody ever thought that aerodynamics was incompatible with bumblebee flight. (At best, certain simplifying approximations may have been incompatible with bumblebee flight — but simplifying approximations are incompatible with any kind of flight, if they're crude enough.)
It's (the criticism) just meaningless drivel. Like Cold Fusion, this idea will stand or fall based on whether it can be reproduced or not.
If it violates conservation laws that have been experimentally confirmed millions of times over, you don't need to bother reproducing it. The criticism is perfectly on target. It's not like this guy's apparatus is working at some scale or energy regime that hasn't been thoroughly tested before, where there might still be new physics lurking.
After all, it's not like it hasn't happened before. (like with Copernicus, then Gallileo, then Newton, then Maxwell, then Einstien, then with Born and friends, then with... Well, you get the idea.)
If you think those cases are comparable to this wingnut's claims, you need to go back and read your history of science again.
But i doubt it would genereate much thrust. Its a lot like the ion engines nasa has.. You toss out charged particles from one end and you get tiny amounts of thrust.
Any more claims then that, id call crackpot..
---- Booth was a patriot ----
I think the editors should have at least some basic understanding of physics. Obviously some do not....
Most ACs are not even worth the keystrokes to insult them. Be generically insulted by this and ignored otherwise.
(A big IF no less) Under the premise that this thing works, he's found a replacement (almost) for the ion drive/thruster. One thing that the article ignores until its reaching a bit past the claimed results is the cooling of the "thruster". That will add weight & require some engery too. Adding 1kw+ heaters to any spacecraft should be done carefully. I doubt this thing can radiate heat faster than it will generate it. (add a coiled cooling tube, have the microwaves heat the working fluid and use that thrust?)
Excuse me, for I am not educated a physicist, but I have some small questions on how this works.
Judging by the drawing, it seems that a lot of microwaves are released into a chamber which they bounce around in, only that one wall is less bouncy than the other walls (i.e. flat and nonreflective) so more of them hit this wall.
My questions are:
- Why can't this be replicated organically, by putting a herd of mice into a room with one hard broad end and the rest padded material, so that most of the mice will exert most force on the broad end?
- Why can't it be replicated with sound waves?
- Why can't it be replicated with photons?
- Why can't it be replicated with a tank of water? (hard jagged wall on one end, rounded on all others, create motion in the water)
- Is the thought behind it that microwaves DO exert force when they hit something, but DO NOT exert backwards force on their point of release? In that case fair enough - sound waves would probably be out - but what about thermal energy? Couldn't you put a match in a room where every wall but one is mirrored and achieve the same effect?
- If the concept is so simple, surely it should have been discussed even in fairly simple textbooks? Basically, if you have a system with a source that generates waves with momentum without itself being subject to the momentum, what happens if you place it inside a box on a trolley and most of the waves are absorbed by one side?
When a photon loses energy by reflecting off the chamber wall, it can't lose speed, so it loses mass.
Photons don't have mass. I think you'll find that it loses frequency, i.e. it gains wavelength. It becomes "redder."
Stick Men
This was the problem with hovercraft (as a replacement for cars - I remember articles from 40 years ago claiming that roads would soon be obsolete). Precise steering is tough, and emergency stopping is really tough, if all you have is thrust from a fan. Not so bad if you are crossing a lake or the Channel, bad if you want to use it in traffic.
I think the key part of your debate falls down with discounting things by predicting theoretical failures before a test is made.
.
.however, if you tell me you have created a "free energy" device by a particularly clever arrangement of magnets I do not have to pay much attention to you, because I have tested magnets. I do not have test every arrangement of magnets in the world.
.nothing.
.
I'm an empiricist. Testing is what I do.
Theory always alters to fit the observed facts.
You'll find my other posts littered with statements that the equations are only models, not the reality and that reality always, always, always trumps the model. In this particular case, however, we are dealing with some of the most basic and rigorously tested facts in history.
There's nothing I like better than running a test that destroys a bad model, because I loath bad models. If the model is suffieciently established there could even be something like a Nobel in it. .
It's also possible to find something that works despite what the equations say.
. .
This is, in fact, one of the primary functions of a model. To allow us to spend our time persuing that which is likely to be true and ignore that which is certain to be false, not on the basis of a priori assumptions, but on the basis of a priori test.
This guy has come up with a scheme with all the hallmarks of a clever arrangement of magnets. From obvious misunderstanding of the phenomena he is dealing with to the belief that if he could just find his way around some insoluable problem with another layer of misunderstanding things will come out all right.
Well, all of that, I acknowledge, is neither here nor there if the device can actually be shown to work. If it works we've got to get back to work on the models. That is how science is supposed to work and you'll find my posts littered with complaints that science is dying because no one works it that way anymore.
But here's the thing. It's his crackpot idea. As a crackpot idea he has to show that it works. As a bystander it's simply my role to retest to find out if/how/why his tests are bogus or not. If they work, he get the Nobel, not me. The onus is on him.
And he hasn't produced results yet. All his careful documentation and measurement show . .
Except a device that just keeps getting bigger and bigger, more and more complicated, heavier and heavier, as he chases down solutions to more and more insoluable problems.
As an old school empiricist I know something that most, even most scientists, seem to have forgotten, that measurement is an inexact science and for a result to be meaningful it has to, inherently, be above a certain threshold. Anything below that threshold is a null result. Any outlying result beyond the threshold is almost always a bringer of false hope if the main bulk of the data is still inside the threshold.
Results at the margin only serve, in the end, to demonstrate the validity of the margin.
Now, a modern automobile engine is a large, heavey and complicated mechanical and electronic object that has evolved over time to solve a whole slew of engineering problems that have arisen in trying to extract useful work from the device, but. .
I can demonstrate that it will, in the end, work with nothing more than a bit of PVC pipe, a bit of potato, a shot of hairspray and a match. The basic principles are, well, basic. I can do an analogous demonstration that a particle accelerator will work with a couple hundred dollars worth of stuff I've got just lying around the lab, on a lab table.
All I can do for his device in the lab is show that it won't work, because the basic principles do not support it.
Based on actual test I have to predict that his machine will just keep getting bigger and bigger, more and more complicated while doing nothing but returning "better" and "bette
>> this engine would violate conservation of momentum ... an incredibly tiny force, a measurement which was given without error bars ... he's probably just measured his noise floor.
If his engine works, none of the above matters.
Indeed, it would be hugely important to Science if it were shown to violate conservation of momentum, because then a heretofore rock-solid theory would have to be re-examined to discover where it's gone wrong.
Science doesn't deal in Truth, and existing fundamental theories are certainly not Truths, they're merely our best current mathematical models representing how reality works.
But reality herself is the ultimate authority, and if the engine works, and if old theory says that this has violated conservation of momentum, then the old theories are flawed.
Let him prove his engine at high Q before criticising the work. All truly new discoveries require old theory to be invalidated under new conditions, otherwise they're not really new. That's how Science works. Theory will catch up, if required.
>> And he hasn't produced results yet. All his careful documentation and measurement show . . .nothing.
He reports in his PDF paper to be generating 214mN/kW at the moment. By no stretch of the imagination is that *nothing*.
I think what you really mean is that you don't believe him, personally. And in addition, you believe that the independent testers were either fooled or not thorough in their testing or their oversight.
Although you claim to be an empiricist, all in all, most of your post is a rant based on your prior beliefs. That's not being empirical.
This purported 'invention' will surely not work. Relativity or not, conversation of momentum still holds true. A closed system (which his cylinder appears to be, at least in terms of E/M radiation) will never generate any net thrust. Even when E/M radiation can escape, it will impart at most a momentum of E/c - a very tiny amount indeed.
And what about the artifacts? Like currents by the microwave field induced in a surrounding metal parts with further standard EM interaction? Or just say magnetic force from a transformer (like for the powerful source for magnetron) to surrounding steel pieces? Or other milion possible explanations - most probable probable of which is pure hoax?
From the very low level of the article I do not believe this guy can properly design an experiment. And from the way he is trying cover up inconvenient laws I do not believe in his honesty either. Pure rubbish.
In association with Steorn!
"and use liquid hydrogen, which boils at 20 kelvin, as the coolant"
Yeah, right. Reminds me of this joke
...then you simply hook the logic circuits of a Bambleweeny 57 Sub-Meson Brain to an atomic vector plotter suspended in a strong Brownian Motion producer (say a nice hot cup of tea).
I mean, if electromagnetic radiation can propel something forward surely gaseos exhaust can?
Like this, right?
What?
Wheel friction is a huge waste of power. Yes, cars are currently designed to propel themselves via their wheels, but only because wheels were necessary at the time, and nothing much better has come along.
If you have a method to allow cars to float, you can change the propulsion method, and have MUCH more effecient cars all-around. See maglevs vs trains for a good example.
Slashdot gets worse every day... Pipedot: News for nerds, without the corporate slant
"Since the microwave photons in the waveguide are travelling close to the speed of light"
... I always thought that speed of the photons is the speed of light ...
...
Hmmm
NEW Scientist indeed
I couldn't care less whether it was reactionless, oscillating or made entirely of fish. What I want to know is does the damn thing work?
I hate to break it to everyone who wants to look so smart by making this point over and over (could we have a few dozen redundants put out there?) but we certainly don't know everything there is to know about physics, and we've been known to be wrong and/or imcomplete in the past.
Yet it is precisely the friction between the wheels and road which make a car go forward. Friction with the car wheels is not bad, you need it. Friction with the air is bad, but not the wheels.
Friction between the wheels and the ground is good. It is usually referred to as 'traction'. However, wheels also have an internal friction known as 'rolling resistance' that is bad. That's why your tires get very hot when you drive. That and the friction with air is bad.
If you could make your car float a bit off of the road and still drive AND that floating didn't cost as much energy as the rolling resistance of the tires, it would be a good thing.
The interesting part of the microwave thruster is that it wouldn't directly expend energy to levitate since no work is being done (the same reason you can levitate a small object on perminant magnets without violating conservation of energy).
In practice, the thruster is nowhere near 100% efficient at this point, so would be a net energy loss.
Actually his real goal is to make a drive going faster than light. Ok, you ask, there isn't any obvious relation of this "invention" to going FTL, is there?
Well, there is: As everyone knows, nothing can be faster than light, with the exception of bad news. So if you want to go faster than light, you'll need a lot of bad news. So how do you get that bad news?
Now, his strategy is as follows: He "invents" some device which contradics the laws of physics. Now what will happen? Lots of people will tell him: "I have bad news for you: Your invention will not work." Now all he has to do is to collect all that bad news until he has enough of it for his FTL drive.
The Tao of math: The numbers you can count are not the real numbers.
Actually, there has been som confusion regarding the ever god damned "speed of light"!!!
/Anon coward who forgot his slashdot pw, and who lost the mailaccount years ago... :(
Now, everyone agrees on that everything in the EM (all of the freq range) "travels" at the "speed of light", so could PLEEEEEAASSE we just say "speed of EM" instead?? Please?
Now, some (and some more than a few) will get confused or at least forced to THINK before they start to treat "photons" different then the rest of the EM range!
Couldn't you just point the fan backward, you know, like this?
My amazing wife - Artist, Author, Philosopher - Laurie M
Shouldn't emergency stopping be quite easy to achieve by switching the hovering mechanism off?
The Tao of math: The numbers you can count are not the real numbers.
Well, it's quite easy to win energy by changing the frame of reference. Let's say I start with a frame of reference where earth is at rest. Now I accelerate a car to, say, 50 km/h. This needs some energy, which now is in the car in the form of kinetic energy (since this speed is hardly relativistic, the kinetic energy of the car is well approximated by 1/2 m v^2, where m is the mass of the car).
:-)
Ok, now I change my frame of reference, so that in my new frame of refernce, the car is at rest, and the earth moves at 50 km/h in the opposite direction. Now I've won a lot of energy, because the earth's mass, and thus the earth's kinetic energy at the same speed, is much larger than the car's. By taking a tiny amount of that won energy to accelerate the car even further, I can repeat that proocedure, thus producing as much energy as I want.
Note to humour-impaired readers and moderators: It's funny, laugh!
The Tao of math: The numbers you can count are not the real numbers.
Forgot to mention Phantom runs on Vista....
Guys I think we are going to get our floating city soon. We take a few of these reactionless drives and hook them up the the free energy from these guys http://www.steorn.net/ and we are good to go.
I'm very doubtful of this. But if the thing really works, then wonderful. Remember, most science is a set of ideas describing observed behaviors in nature. This might be something yet unobserved.
I really didn't pay much attention in physics, but I seem to recall that when a thing is moving faster, that is, it has a great deal of energy relative to one point of observation, that, from that point of observation, it can be said to have gained mass. Kind of like how a baseball thrown at around a hundred miles an hour will weigh a few thousands of a gram more while in motion than when at rest.
Edward@Tomato - /home/Edward/ man woman
man: no entry for woman in the manual.
"Qua!?"
It can only gain mass with speed if it has rest mass. Photons have zero rest mass. Zero times anything is zero.
Look up the Lorentz Transoform for how to calculate length contraction, mass increase and time dilation. Now try your baseball thrown at 100 miles an hour. You'll see that you have to be going at over half the speed of light to make any appreciable difference.
The momentum of the photon has nothing to do with mass.
See also "Special Relativity" by A P French, ISBN 0-412-34320-7, if it's still in print.
Stick Men
Yes, acceleration would be easy enough to replace with another method, though. Controlled deceleration would be much harder.
Comment removed based on user account deletion
That would hardly be a controlled stop, and I don't know how functional the vehicle would be aftewards...
> 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.
Sounds like he's already sold £250,000 worth of snake oil.
Warning: this article may contain humor, sarcasm, parody, and perhaps even irony. Read at your own risk.
Im not a physics major or anything, but to me alot of what of he is proposing sounds alot like some of the stuff Tesla was talking about. Is this really new??
Doesn't the cosmic background radiation from the big bang create an effective
"stationary" frame of reference? In other words you measure your velocity in relation to a projection of the original singularity that created the universe.
We are the 198 proof..
In a vacuum, photons travel at "the speed of light", since that phrase is usually shorthand for c, the speed of light in vacuo. However, in a medium such as air, the speed of photons is less than c, and varies (slightly) depending on frequency.
Not that I'm saying that this isn't rubbish. "Relativity" is not the magic word the author seems to think it is.
Ben Hocking
Need a professional organizer?
The CMB does indeed provide one (useful) stationary frame of reference. Of course, there are lot of other useful stationary frames of reference. The CMB does not have some magical power in special, or, general, relativity.
Ben Hocking
Need a professional organizer?
It's the same phenomena as when you move across the room in a swivel chair (without touching the floor) by shifting your body-weight around.
Overly simplistic. Add in some vague references to quantum mechanics, mass vs. trajectory dynamics in thermal ambiguousity and at least one pi.
...you're going to have to show me that they are there before I go spending time and money putting food out to mollify them.
Wait - should I now infer that all those cookies I left *weren't* actually eaten by Santa Claus?
"I shall call it, Project Jiffy Pop" -Dr. Evil
Wait - should I now infer that all those cookies I left *weren't* actually eaten by Santa Claus?
I'd set 'em in a bear trap if I were you.
KFG
> Even a cursory glance at the article would have been enough to convince
> anyone that it's unintelligible garbage.
Only if the person doing the glancing understands elementary physics. That lets out the Slashdot editors (and most of the posters as well).
Warning: this article may contain humor, sarcasm, parody, and perhaps even irony. Read at your own risk.
It's worthwhile here mentioning that the speed of light, from the photon's "point of view", is nigh-meaningless because from it's point of view it's traveling instantaneously. Very few non-scientists, even those who know a bit about Relativity and think that the concept of Time Dilation is cool, understand the rammifications of Space Dilation as well. It's not just about time bending--space bends, too. The entire universe actually contracts on the axis on which the photon travels. This is not an "illusion"--from its own point of view, the photon actually doesn't "travel" at all because the universe has become two dimensional--up, down, right, and left still exist, but the universe has contracted so much that forward and back have no meaning anymore--from the photon's point of view. c as a measurement of velocity only has a meaning for those of us out here moving at non-Relativistic speeds. People say that it would take you millions of years to go from one side of the galaxy to the other even if you traveled at the speed of light, but that's blatantly false. If you could travel at the speed of light, it would be instantaneous... for you. For the rest of the galaxy, millions of years will have passed.
A bit tangential, maybe, but it's worth keeping in mind when people start talking about a photon's frame of reference.
Doesn't the cosmic background radiation from the big bang create an effective
"stationary" frame of reference?
The Big Bang did not happen in a particular location of the universe you perceive; the Big Bang was the entire universe at the time. Cosmic background radiation propogates in all directions from all reference points.
There simply is no such thing as a "stationary" frame of reference...they are all identical.
Big Oil kills this guy and everyone who knows anything about?
If you could reason with religious people, there would be no religious people
I enjoy reading your comments, but your sig bugs the tar out of me. The line should be "Kinky is when you use the whole chicken." I've also seen it as ""Kinky is using a feather -- Perverted is using the whole chicken."
But "exotic" (which basically means "foreign" or "not native to this area") makes no sense and kills the joke. I know it looks like "erotic" but it's a completely unrelated word.
--MarkusQ
Human accomplishments are catching up to our vocabulary, if you get run over by one of those mofos you really are "toast" and not just "mangled".
http://www.shelleys.demon.co.uk/fdec02em.htm
Jet engines take massive amounts of air in on one end and blast it out on the other end, it's not the exhaust that's propelling it, it's the air that got sucked in.
// MD_Update(&m,buf,j);
Ok, I was with the rest of the crowd on this one as obviously a pathetic snake oil attempt, but then I have a revelation. I thought, we'll if it worked for microwave pressure, surely it could work with air pressure. I machined an aluminum cavity in my shop, roughly canonical, with two flat ends to match his drawings as best I could, fitted a pressurization fill pipe to it and then welded it together. I pressurized it to 40 psi, and then measured the thrust just like he did, on a scale, first with the smaller end up, than the smaller end down, and sure enough I obtained a difference between the two of 3.7 pounds.
I was ecstatic. I wondered about higher pressures to obtain yet more thrust and soon I had built a high pressure vessel out of high carbon steel (the boss won't miss small amounts of stuff) and I decided to pressurize with with nitrogen instead. I got it up to around 980 psi and sure enough, when I pressurized it, I noticed that the restraint system I had built started to strain and I was pleasantly pleased when I finally got the readings of some strain gauges I had added to the restraint tie downs. I didn't have to turn it over this time, as the whole system only weighed in as 60 pounds and yet it delivered 2,398 pounds of thrust.
I'm not going to include my drawings as I'd like to get someone to pay me for my work before I share some of the details. If someone would like to send me money, just let me know. I'm eager to prove to everyone that cheap space travel it possible and this would be great technology to get to Mars and beyond.
Search patents for Dean Drive
Repeat after me: They did not stop a photon! c is still c! I WILL NOT SHOW MY IGNORANCE ON THE TOPIC OF PHYSICS ANY MORE!
Maybe it does radiate some massive photons if movement occurs. I mean it would have to, right?
Which might not be very good on Earth.
I wonder if this is something that works only if no work gets done, i.e. you can measure the force if everything is fixed, but if you let it accually do work, all the power drains as it emits something to conserve momentum.
I have to think about this more. Whatever the truth of this, it is an interesting idea. I haven't thought about Physics for awhile.
I really do not trust that "Relativistic Correction Factor".
That is a transformation that is appropriate for calculating how things change when you change your referenece system, and I don't see him mentioning that here at all. Like maybe that would be appropriate if he were trying to calculate the thurst from the point-of-view of something riding along with the waves, but that is pretty irrelevant to trying to move a satellite.
His reason for using them are all wrong. For example if you see two spaceships moving directly away from each other at 75 percent of the speed-of-light, then you see them moving away from each other at 1.5 times the speed-of-light, and no correction is needed in your reference system. Of course the spaceships would see something different, and that is what the addition law is all about.
He starts out with that equation in his whitepaper, but I can't see it applying here.
Maybe I am looking at it too simply, but that Lorenz force equation describes forces on charged particles (with a charge of q), and he is talking about Electromagnetic waves here. When these are considered as particles (photons) they have no charge.
Of course it is maybe irrelevant, because the argument he describes there is not actually used anywhere else in his paper where he elaborates his theory, as least as far as I can see.
This is a working model. All they need to is improve a piece of ingeniousely designed waveguide to reduce energy losses (improve the 'Q' value) using cryogenically induced superconductivity. The article mentioned 30000 Newtons from a kilowatt of input power. This is with one device!
Put three or more on one craft with a crew compartment pressurized for hard vacuums an shielded from cosmic and alpha radiation, etc.; and with a nuclear power source of, say, half a megawatt or so and you have a true shuttle. Scale it up and you have a starship. From what Shawyer has, a working device, this is no longer science fiction. The only real question is why our defense establishment and the English defense establishment refuses to see the value of this. Certainly the Chinese do. Could it be that traitorous individuals rule the defense departments of both England and the United States?. Or could they be so shortsightly stupid as to believe that something THIS bis could be hidden until 'the oil runs out' or 'the last fossil fuel profit dollar has been squeezed from an exploited world'? Now WE know about it! Are WE to be now targeted by 'extraordinary RENDition' for torture in Syria or Afghanistan because we 'know too much'? Barring a convenient car accident ala 'Princess Diana' or a convenient helicopter accident like ex Democratic leader Brown who 'crashed unfortunately in Bosnia' in the 1990's, Mr. Shawson may well become: a billionaire; a Nobel Prize winner MULTIPLE TIMES; and a transportation tycoon greater than any in the history of man. The inventor of star travel in the Star Trek series was named Cochran. The real star travel inventor may well prove to be Mr. Shawson.....if he is allowed to live and doesn't end up like Gene Mallove. But now the world knows how to do this trick with unbalanced forces in a waveguide, and will not forget it!
No matter how the monopolists try to bury it.
Excuse me, the article said "30 millinewtons". That's three hundredths of a newton, not thirty thousand newtons.
It's still more impressive than the ion drives in use on some probes, but it's no fucking shuttle.
When I was a kid, I used to think that New Scientist and Scientific American were somehow comparable because they both have "science" in the title. That's misleading, though. The point of this microwave drive article is really just so the author can say at the end "gee whiz, imagine if we had such a drive". The fact that it isn't going to happen doesn't matter. In that sense, New Scientist is much more like the old Omni magazine - a blend of scifi and questionable gee-whiz science news from the fringe. Except Omni was more interesting.
Oh, and BTW, the inventor of the microwave drive isn't dumb - he's already built in his prediction of why the drive won't work - buried in the article is the observation that once the drive starts moving, it's output will drop[*]. But even assuming the drive somehow works, the goes the "strap a nuclear reactor & go to Saturn" scenario is ruled out by the inventor's own description of the drive's capability.
[*] This is perhaps a restatement of conservation of momentum, and once the tests are done it'll turn out that the net useful energy this drive can produce is... zero. How surprising!
Until I got near the end of the article, it seem as though things were a little screwy (e.g. 30 KN of force with a KW of energy). However, the whole part a bout bleading off energy as it accelerates makes some sense.
Think of a table. If you place a paper clip on it, it puts a few millinewtons of force on the table and vice versa. If you place an elephant on the table (assuming it doesn't collapse), there are a lot of Newtons. How much energy was expended by the table to hold up the paperclip or the elephant? None. The objects didn't move, even though there was a significant force on them.
Other thoughts
-It sounds to me like this guy figured out a way to make a hover-board type drive a la "back to the future".
-Can the device "slide" out of the earth's gravitational well? As it moves further away from an inital point with its axis pointed at the earth's center, the plane perpendicular
-What happens if you try to change the orientation of the emdrive? Compare with re-orienting a spinning gyro.
-If power is not a problem (think nuclear), what mass/thrust ratios are possible?
science is a religion
"There simply is no such thing as a "stationary" frame of reference...they are all identical."
Not all reference frames are equally "stationary".
Consider this example: imagine an inertial reference frame with three motionless spacecraft. Time passes equivalently in each spacecraft as long as they remain motionless relative to each other. Consider what happens if the first two spacecraft depart in opposite directions from the third: the rate of the passage of time is now different for each spacecraft.
Question: In which spacecraft does time now pass the most swiftly (i.e. where you grow older most quickly)?
One anser is the third spacecraft, i.e. the spacecraft that didn't change its velocity. What the answer be if you were told that all three spacecraft had initally accellerated in the same direction as the first spacecraft and that the second spacecraft ended up accellerating in the opposite direction by the same amount? In that case, the spacecraft where time passes the most quickly may be the second spacecraft. I use "may" in the second part because we don't know how the spacecraft may have been traveling prior to the above.
So if such a reference frame exists, we should be able to find it, right? Do this by measuring the mass (or gravity) produced by an object as it moves in different directions. One way may be to spin a disk i and carefully measure the grafitational pull along the edge.
As long as the disk is forced to spin about its geometric center and it is not moving along its axis, the center of mass should shift to one side. Repeating the experiment in multiple orientations could allow one to back-calculate the velocity of the reference frame where the experiment was performed relative to the "non-moving" reference frame.
There has to be a reference frame where time passes moste quickly. I have encountered several well-credentialled physicists (one a NASA physicist giving a graduate seminar lecture at the U of MN) who agree that there must be a "universial" reference frame that is "stationary", or "at rest", relative to all other "intertial" reference frames.
Your thoughts?
science is a religion
Okaaaay...How 'bout this?
What?
More thoughts:
-What happens to an emengine in a structure fixed to the earth's surface as the earth rotates?
-What happens to it as the earth orbits the sun? Milky Way? Etc.
-Would it a "fixed emengine" actually put a force on the Earth, changing its orbital mechanics (by a tiny bit)?
science is a religion
If so, obviously not for the reasons given by Roger Shawyer. But, what if we could generate an enormous amount of stored electromagnetic energy that was somehow asymetrically distributed? How would it affect local gravity? We know that the Reissner-Nordstrom solution of Einstein's General Theory creates a "repulsive" curvature which at some point cancels out the gravitational curvature, then dwindles rapidly with distance. Einstein's curvature equations haven't been and probably can't be solved in closed form for this problem. Does anyone out there know if there are numerical solutions which show what might be the curvature surrounding a resonating cavity?
You can find the flaming here and the grovelling apology on their blog.