China's Radical New Space Drive 419
First time accepted submitter Noctis-Kaban writes "Scientists in China have built and tested a radical new space drive. Although the thrust it produces may not be enough to lift your mobile phone, it looks like it could radically change the satellite industry. Satellites are just the start: with superconducting components, this technology could generate the thrust to drive everything from deep space probes to flying cars. And it all started with a British engineer whose invention was ignored and ridiculed in his home country."
Doesn't work (Score:5, Insightful)
From the article: "Seems to violate law of conservation of momentum". - Yup it does. Imagine putting an invisible mass-less box around the entire system. Almost nothing comes out the back (only microwave energy - more on that later). The center of mass of the box accelerates. This is a violation of conservation of momentum - one of the most well understood and best tested laws in physics. If there were some exotic high energy physics effect proposed for this at least it might be worth listening, but this is just electromagnetism - very well understood. The "group velocity / phase velocity" is just jargon that has nothing to do with this since it is the Poynting vector that carries momentum.
You CAN make a reaction drive using photons (microwaves in this case), this idea has been around for many decades. The problem is that photons carry a lot of energy relative to their momentum so it takes an enormous power source to produce any thrust. So far no one has found a practical application where there was a large enough energy (and high enough power ) source to make this practical.
There have been a lot of experiments with microwaves - I've personally worked on a 600MW pulse microwave system. There have even been attempts at microwave driven spacecraft sails. Some early experiments seemed to indicate more thrust than would be expected from momentum conservation. Eventually this was tracked down to gas absorbed on the surface being heated and released by the microwaves - essentially a conventional rocket. With very high microwave powers you can generate forces in all sorts of ways in a closed laboratory environment that would not work in space.
This will not work.
this post will be remembered (Score:1, Insightful)
...as the point in interweb non-spacetime where/when slashdot's u-turn from interesting to crass became self-evident.
so long, /. been a fun 10 years. my gratitude, respect & good will as i permanently depart.
Re:I'm pretty sure it doesn't work (Score:5, Insightful)
I'm sure if the drive was useful in any meaningful way it would have been utilized.
Kind of like if Robertson screws were better than Phillips screws, they would have been utilized by Henry Ford? That stuff often doesn't work out the way sane people think it ought to.
Re:I'm pretty sure it doesn't work (Score:3, Insightful)
Re:Doesn't work (Score:3, Insightful)
And for everyone still reading: that's where it all ends. Nothing more to be said. Anyone who's not deluded understands that seeing any measurable thrust in such experiments is a prima facie evidence that your experimental method is broken. The better your experiment, the less thrust you should measure. That's all there's to it. Undergrad physics lab, it sounds like -- to me at least.
There's also some indirect evidence of fraud, even if non willful. How the heck is it that all such "genius", "unappreciated" world-altering inventions go through hype, secrecy, bilked investors, and nothing ever comes out of them. Nothing. Na da. Whatever grants this guy got pretty much amount to defrauding the taxpayer. You can't do this kind of shit in good faith. Pretense of being on a verge of something big is just that. It's not about any conspiracy to maintain any sort of a status quo by the "big guys/industry/villain-du-jour", or about suppressing anything. It's just that we've got basic physics figured out quite well already, and it doesn't seem like simple experiments that don't involve billion-scale investment are really going to be redefining our basic understanding of things. There are quite few engineering accomplishments to be had with small monetary involvements, but not basic law-of-nature type experimental results in physics -- not anymore, I don't think. I'd love to be proven wrong on that, of course.
Re:Doesn't work (Score:2, Insightful)
Well, you'd be fascinated and intrigued by this new research and working model then? surely?
Surely you'd be interested in replicating his experiment, if only to prove it doesn't work.
Seems to be there's a lot of not-science going on here...
Without wanting to comment on this particular (Score:5, Insightful)
experiment (since IANAP), I do want to say that there seems to be a troubling trend amongst the best and the brightest in many STEM fields to mistake theory for reality. Theory is great and proceeds under the scientific method from empirical observation, but as we've seen throughout history, new phenomena and corner cases to arise and require theory to be amended.
It's fine to say "this is clearly unlikely to work under current theoretical understandings" but let's also refine and do the experiments to the best of our ability so that science remains scientific (i.e. nominally empirical and ultimately practical in nature). There's a difference between taking "current theory suggests this is likely to fail" as a statement of fact and mistaking theory instead to be *evidence* about experimental outcomes.
No theoretical argument can be evidence for the reality or unreality of phenomena, no matter how well-formed. That's not to say that we ought to mistake the phenomena at issue—it's obviously critical to be able to understand, rather than misconstrue, the reality that we observe—only that sometimes a generation or two of scientists seem to get complacent and imagine that they've got the world all figured out after all.
Let's continue to do, and—to the best of our ability and within reason (but with "within reason" here broadly defined—allocate resources for, actual experimentation and empirical observation of the world around us.
Not that we don't—but to my eye, the attitude that if theory doesn't support it, it's always a waste of money to test it out experimentally, is a dangerous one for the future of a science that is far less uniform, linear, and accumulative in its progress than we often tend to remember.
Re:Conservation of momentum (Score:4, Insightful)
A surprisingly non-sceptical article; I'd expect a bit more critical thinking from Wired. Terms like "group velocity" and quantum theory", used vaguely, don't help you avoid the fact that conservation of momentum is fundamental to modern physics. It's just as inviolable as conservation of energy.
To put it another way, this article makes Wired look just as gullible as they would if they wrote "Scientists in China have built and tested a perpetual motion machine."
It's really the same thing as the conservation of energy. What we really have is the conservation of four-momentum, which is standard special relativity. You can Lorentz transform one (energy) into another (momentum) (within limits).
Re:Doesn't work (Score:4, Insightful)
I do know that it's tricky to do this stuff correctly, that why you should doubt yourself more when faced with supposedly extraordinary results. Doubt more, not less. All I remember from numerous labs that extraordinary results meant you'd have to keep redoing it until it got ordinary again. I'd have really thought that people who did any sort of engineering or physics undergrad labs should have had such basics explained to them. I'm playing with getting the 4th digit to agree well with theory in a simple mechanical pendulum, and the dreaded thing highlights that everything you thought could be ignored, can't. You have to engineer it to work -- look at all the numbers, for all effects you can think of, estimate their magnitudes, verify that you do in fact see the effects, and then mitigate. Good old experimental engineering. You get small but cumulative payoffs for diligence and a certain sense of accomplishment -- I do at least. Simple life's pleasures :)
This non-drive, given the power pumped into it, simply magnifies all the effects people can ordinarily ignore. It's a nice educational tool. I think good schools should add such a thing to their lab curriculum, so that the students will get some experience in how easy it is to fool oneself. There are probably other similarly spectacular experiments that would serve the same purpose, of course -- even a basic large mechanical pendulum.
I can't get over the fact that people with money who fund that sort of thing are so gullible, though. I mean, give me a fucking break, they seem to be just as gullible as the investors were 100+ years ago when faced with all sorts bullshit when the telegraph, telephone and electricity were getting into high gear. Hans Camenzind's little jewel of a book "Much ado about almost nothing. Man's encounter with the electron" is a sad testament to how little things change in that respect. The dumb will be parted with their money, all the time, all the same.
Re:Without wanting to comment on this particular (Score:5, Insightful)
Agreed.
Also just trying random stuff to see what happens is likely to end up with experiments that are subject to all sorts experimental errors. If you have a theory that electromagnetic radiation doesn't conserve momentum, then you design a specific experiment to look: If you think its a high field effect, you do particle collisions, or relativistic particles in intense laser beams. If you think its a small but linear effect you do superconducting microwave cavities suspended on ultra-sensitive force balances. You don't start out trying to build a rocket engine.
Re:FAQ from Dr. Shawyer answers a lot of questions (Score:5, Insightful)
It blatantly violates conservation of both momentum and energy. It's advertised as being useful for spacecraft propulsion, changing the momentum of the spacecraft without emitting anything that would carry equal momentum in the opposite direction. If Shawyer's claims were true, an EmDrive placed on end in a gravity field would be either an energy sink or source (depending on orientation) with infinite capacity. I see no reason why anything else on the site should be treated as any more trustworthy.
Re:Primitive and woefully inadequate (Score:5, Insightful)
From my perspective, Einstein muddied the entire subject by equating reality with what is observed and using that false premise
The new scientific method is here! Make some wild guess about how the universe must work because that's how you'd like it to work, then call all previous work foolish and flawed. Done. Wait, didn't we used to do something similar to that?
Re:Without wanting to comment on this particular (Score:2, Insightful)
Without wanting to comment on this particular experiment (since IANAP), I do want to say that there seems to be a troubling trend among the laypeople of the world to mistake crackpots for scientists.
Re:I'm pretty sure it doesn't work (Score:4, Insightful)
Considering that energy must be supplied to it, it no more violates conservation than an electric motor.
Re:Skepticism (Score:3, Insightful)
Re:I'm pretty sure it doesn't work (Score:5, Insightful)
I first saw a working model of a scramjet in 1986. It wasn't the first one. now it's 2013 and it hasn't been "utilized" yet in a "real-world application" but it is on track to do so. That should show you that you can't expect instant results with propulsion systems and that your assumption that something is worthless if you don't get quick results is wrong. Instead the thing itself has to be considered on it's own merits and not whether it's on the shelf at Walmart yet. There are plenty of reasons why Boeing may not immediately jump on a new and unproved technology that have nothing to do with whether it's viable or not. We'll need to get information from another source instead of just making a wild assumption based on it not being commercially available this instant or other unreasonable expectations.
Re:We can always hope, but... (Score:4, Insightful)
If you imagine that - you need to study up on your history. It was known that the earth was round and orbited the sun a long, long time before those two showed up.
Stop arguing and TEST IT! (Score:3, Insightful)
Just get one of these things and test it under rigorous scientific conditions and scrutiny.
If it works, it works; If it doesn't it's back to the drawing board and we can all move on.
Al this fucking shitbrained arguing over nitpicky sematic points is just maddening. Put up or shut the fuck up, because we don't want to hear your not-based-on-anything-that-counts armchair scientist opinions.
Re:Stop arguing and TEST IT! (Score:5, Insightful)
Just get one of these things and test it under rigorous scientific conditions and scrutiny.
If it works, it works; If it doesn't it's back to the drawing board and we can all move on.
Al this fucking shitbrained arguing over nitpicky sematic points is just maddening. Put up or shut the fuck up, because we don't want to hear your not-based-on-anything-that-counts armchair scientist opinions.
"Just get one of these things"
You know who has one of these things? The people who built it. You know what evidence they can't put up? The type which discredits a very obvious criticism. One would think with that type of headstart and knowledge of its operation and experience with test setups, this type of demonstration would be an obvious one.
Re:Skepticism (Score:4, Insightful)
"Sorry, no. The whole point of skepticism is to assign a negative (false) value to anything but proven assertions. You may still be in the realm of empiricism, but you are not being skeptical."
Not at all. As a skeptic, it behooves me to judge which is more likely, based on actual evidence. (And if I do the job properly it should be good, solid evidence.) But if I waited until everything was proven I'd be waiting past the heat death of the universe. As "causality" pointed out, what you advocate is positivism, not skepticism.
I'll never understand why simply saying "I really don't know, but it may be possible" is so damned difficult.
It seems to me like another silly ego game to declare something false when it has not been falsified, (ab)using the concept of positivism by taking it to an extreme just so you can tell somebody else that they're wrong. Yes, the burden of proof is indeed on the person making a claim, but hiding behind that to smugly declare that something "is false" is a roundabout way to make a claim yourself (that something is false) while excusing your own burden of proof (falsify it or admit you don't know). It's an attempt to put the other person at a disadvantage to "get even with them" for having a different inclination.
If you look deeply at human behavior, you will see for yourself that most people have a desperate need to feel superior in some way to another human being. It is not enough that someone be right; someone else must also be wrong. It is not enough that someone explains their opinion; someone else's must be bullshit. It's not enough to disagree with something; the other person must be put down or mocked or denigrated in some manner. Always there is an attempt to hide this by giving it the appearance of legitimacy.
Yes, in hard sciences positivism is a good thing. It prevents a lot of pseudoscience and weeds out a lot of false notions. But there is a distinction between "we're going to treat this as though it were false for now, but if you have other evidence please show me" and "this absolutely is false and I'm closing my mind now".
As far as it concerns Slashdot, I wish people would grow up, get some emotional maturity, deal with their petty little insecurities, and realize that the only real sense of worth human beings ever find comes from within yourself. It does not come from the relativity of making another person look worse than yourself and the attempt to do that is completely childish. Sadly it's also accepted as normal because it is so common.