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NASA Still Trying to Verify Anti-Gravity Claims
uncoda writes "The L.A. Times has an article about NASA research into a phenomenon in which the effect of gravity is supposedly reduced. It sounds like cold fusion or polywater to me, but who knows?" We've posted two previous stories about Podkletnov's research: one from a couple of years ago and another more recently.
If the experiments succeed it may give us some insite into gravity but don't look to this device to free us from the bonds of Earth.
A super cooled, electrically charged, rapidly spinning super conducting disc that reduces the gravity field above the disc is interesting. However, taken as a whole, the entire system would still crash to earth.
Sort of like putting a sail on one end of a skateboard and a fan blowing air on it on the other end. It still isn't going anywhere.
The race isn't always to the swift... but that's the way to bet!
Is this effect similar to that of the levitating frogs? [I dont have a link handy... anyone care to help?]
If so, could the rotating simply be acting to create a focus point of magnetic energy at some point on the axis of rotation, above the superconducting disc? If the object being tested has any magnetic substace in it at all, then a strong magnetic field could cause it to seem less weighted, right?
I also question the use of the Cavandish balance to measure the mass of the item above the spinning disk. We're dealing with a superconductor in a magnetic and electric field... What is preventing this device from causing some strange magnetic effect. What about ionization of the air around this device?
These are just my inital reactions to the article, and I'm no Physics expert. What are your thoughts, friends?
All the space probes we can measure are slowing down. The ones where the effect is most oticed are teh GPS sats since they have real good clocks and we know where they are and the long distance Pioneer and Voyagers. NASA isn't sure why this is happening. They know its going on and need to find out why.
If I do an experiment where I can show gravity doesn't work like its expected to, they will look into it. Most of the time the result is that somone put an Acme magnet in the wrong place. NASA doesn't care what the experimentor's (or crackpot's) theory is, they want to duplicate the experiment and try to find out the real reason for the change in mass. If your respected enough to do an expirment, its worth their time to look into it even if your theory is the disk weighs less because of the magic elves.
Actually, perhaps, mass loss. AFAIK, mass is the constant of proportionality between weight and acceleration. If the rotating disc is lowering the weight of something, still on Earth, why do you assume the disc is disrupting gravity and not lessening the mass of the object?
Antigravity is a lot older than 1992 kids. That's just when it became fashionable to be an antigravity crackpot again. Here's an idea, rather than wasting your time trying to make antigravity devices to power some future space ship, why dont you spend your time trying to make a gravity device that we can put on our existing space ships and space stations? A decent gravity simulator is desperately needed for the human mission to mars (which may never happen in this economic climate) and other long term space projects, and frankly, if you cant make a gravity device, what chance do you have of making an antigravity device?
How we know is more important than what we know.
Leaving aside the trivial counterexamples some others have offered (F=GM1M2/R^2), this is actually 100% wrong, as would be known if you consulted anything higher than a high school physics textbook. Even if you want (as the post seems later to imply) to disavow a connection between gravity and inertia, you'd be wrong. Gravitational mass is the same as inertial mass. This has been both empirically validated for 350 years and theoretically established by the Equivalence Principle in General Relativity. Gravity and inertia are one and the same, in ways we don't entirely understand.
So if you could actually reduce G, which is what these guys basically claim, you would indeed be reducing the inertial mass as well. Of course other weird effects would have to propagate, as well.
The Mongrel Dogs Who Teach
To be fair, most things that NASA does are crackpottery, until they work.
But in this case, they really are pushing the boundaries of credibility.
A (crack)potted history of Podkletnov goes something like this. Podkletnov throws together a bunch of superconducting junk that he has lying around his lab, and spins it up. He then waves some instruments at it, decides that he's seeing a 2% reduction in weight, and ascribes that to a reduction in gravitic mass (he can't test inertial mass, as he can't move the mass).
So far, so good. Stranger things have happened through serendipity. Podkletnov has no theory to explain it, but that's incidental. All he needs to do to obtain credibility is to publish all details of his experiment so that it can be replicated.
He fails to do this.
Instead, he publishes a vague description of the apparatus, and continues to make the claims. He refuses to disclose further details, or to let anyone examine his apparatus. Eventually, his university becomes so tired of his antics that they terminate his employment.
Various people with more money than sense try to replicate the experiment. Nobody who claims to have seen the weight loss will publish their details. Sound familiar? To anyone who reports that they cannot replicate the result, Podkletnov replies that they have the details wrong, but he still won't tell them what the details are.
Enter NASA. With some input from Podkletnov, NASA spends $1 million and thinks it maybe kinda might be seeing a 2e-6 reduction, sorta. Podkletnov suggests a few changes, but he still won't just give them his details, and NASA spend another $1 million, at the end of which, they stop claiming that they even might be seeing an effect.
And so here we are again. Someone's scraped together the spare change from other projects, and they've maybe, kinda, sorta got some details out of Podkletnov now. Or not. Who knows? Probably not NASA, and almost certainly not Podkletnov.
Podkletnov is a poor scientist, but a great publicist. Maybe that's what gets funding in NASA these days. It certainly gets publicity, as this discussion proves.
If you were blocking sigs, you wouldn't have to read this.
Er, no. If you've read "The Structure of Scientific Revolutions", you'll see that 95% of all science is hidebound to their assumptions. Great leaps forward happen when enough young scientists (not bound to the previous theory, since they didn't build their career on it) find enough data that doesn't 'fit' with the current theory.
Once the weight of these new scientists is great enough, there is a violent 'paradigm shift' to a new theory that fits all the old data and all the new.
Zapman
(first, correction in your post: you want F = GMm/r^2, not g: g is 9.8 m/s^2, which means it can't have any variables in it. it's g = GM/R^2, where M is the Earth's mass, and R is the Earth's radius)
Not really: G is a conversion factor between mass and force, making it a coupling constant (like Coulomb's constant) - it's more a field strength than anything else.
Note that you can make G go away with a convenient choice of units (mass is mass is mass: they would still have the same units - grams - even if you had inertial and gravitational, just like kinetic energy, potential energy are both measured in joules). For the rest of this, we'll work in units (call them 'statgrams') such that G = 1 Newton-m^2/statgram^2.
When people say that gravitational mass is the same as inertial mass, we mean: force is equal to inertial mass times acceleration, and force is equal to gravitational mass of the two objects divided by radius squared.
OK, so F = (m_i)a , and F = (m_g)M/r^2. Now, when we say that gravitational mass is the same as inertial mass, we mean that if you set these two forces equal, so gravity's providing all the acceleration, the inertial and gravitational masses cancel, that is, g = (m_g/m_i) M/r^2 goes to g= M/r^2.
There are several ways to test this, and all any of them can test is that the ratio is constant (indep. of radius, indep. of inertial mass, etc.) and so we set this constant to 1.
It's a subtle difference, but there: there're two different things that're in the force equation, a coupling of matter to matter (G) and a conversion between gravitational mass and inertial mass (m_g/m_i). Setting one of them to 1 doesn't necessarily set the other to 1, but since they're both 'unit choices', you can freely set them both to 1. The important thing is that since all derivatives of m_g/m_i appear to be zero, it IS merely a unit choice. If there WAS a difference, you could set G to 1, but not m_g/m_i.
One other thing: quantum-mechanically, it's not surprising that gravity is solely attractive: it's a tensor (spin-2) field, which IS solely attractive. That part's understood (We know that a spin-2 field can mimic linearized GR - that is, GR in the weak field limit).
I am concerned that NASA is funding non-falsifiable research. It is certainly true that it would be mind-blowingly neat if this experiment happened to demonstrate something that we couldn't explain.
However, suppose the experiment fails to demonstrate the sought-after effect. This does not constitute a victory for the existing models, because Podkletnov just says, "Oh, you didn't use the right superconductor," or the right temperature, or something.
There is no way to disprove his theory. That's called "non-falsifiable". Non-falsifiable theories are generally unproductive because you can never stop trying to prove them; you're caught in an infinite loop. Eventually you just lose interest, or start to apply Occam's Razor.
It does not bother me that NASA should pursue research with a low likelihood of yield when the potential benefits are high. But whenever someone posits a non-falsifiable theory you must be suspicious, because it's the mark of somebody who is trying to get you to waste time and money.
Note that "falsifiable" is different from "not easily proveable". I can't really go out and check that those points in the sky are really massive hot balls of gas. But at least theoretically it's possible, just not convenient. And I can run other tests which could disprove my hypothesis. I can prove that they're not real close, for example, by sending up a rocket ship. I can check that they happen to produce light in the same fashion that really hot things do. If these tests fail, you know that my theory is wrong.
Inventing non-falsifiable theories is easy; you just leave a variable unbound. (That's the more general, and more useful, form of saying "you can't disprove a negative." You _can_ disprove a negative; I can prove that there's no elephant between me and my monitor right now.)
Because creating non-falsifiable theories is both easier and less productive than creating real scientific theories, but make it possible to fool people into believing something they want to believe, such theories must be treated with extreme suspicion, especially when somebody has something personal to gain out of it. The theory is not necessarily wrong, but the odds decrease drastically, to the point where the probability * cost is lower than the potential value.
The potential value may be very high here, but $2.6 million is non-trivial money, even for NASA, and the probability is vanishingly small.
In order to make Interstellar travel a reality, we need to make a revolutionary jump in technology. Since examining the known laws of physics isn't producing the answers we need, NASA is looking at the prospect that we may not understand the nature of the universe as well as we like to think we do. We need to remember that the "Laws" of physics are theorys that have merely been proposed based on experimentation and observation. Throughout scientific history there have been some discoveries that some things we though were proven absolute, were only true for the many different situations in which they had been tested. The ability to shield an object from the effects of gravity is pretty far fetched, but so is interstellar travel. NASA is going to have to spend a lot of money checking out some radical theories. In the end most of the research won't turn up anything useful. In some cases it will turn up usefull information but not prove what they are trying to prove. One of the important things to note here is that this kind of research needs to be funded by the government because private industries just aren't likely to invest money on concepts that are such longshots, and would take far too long to produce a return on investment. It's true that most of these ideas won't pan out, but through NASA, our government is making a long term investment in our futures. Maybe this isn't as important as some more short term needs like Welfare and Defense budgets, but that's why we spend billions on those things, and millions over years on ideas like this one.
In this case, the money spent on this project is rather small, in a NASA budget expense -- but even with a 2% chance of partial success, the amortized savings as a result of even a pointer in the right direction are enough to make the fool's rush more than worth it.
As was vaguely aluded to in the article, the possible PR cost to NASA's credibility was probably more of an impediment to funding this venture than the financial cost.
Think what would have happened if people had refused to fund semiconductor research? I mean, really! Electronics on silicon??? That stuf is almost an insulator!!!
Sometimes boldness is in fashion. Sometimes only the brave will be bold.