Can Superconductors Block Gravitational Fields?

jswitte writes "Raymond Chiao, of the University of California at Berkel, believes that superconductors can convert electromagnetic radiation into gravitational radiation. His full paper can be found here. His theory is based on the idea that superconductors might be able to block the so-called 'gravitomagnetic' field just as they block the electomagnetic field in the famous Meissner effect allowing superconductors to levitate in magnetic fields. He claims that when he 'adds the gravitomagnetic field to the standard quantum equations for superconductivity, he confirms not only the gravitational Meissner-like effect but also a coupling between the two breeds of magnetic field. An ordinary magnetic field sets electrons in motion near the surface of a superconductor. Those electrons carry mass, and so their motion generates a gravitomagnetic field.'"

Comments

Note that it can't generate antigravity fields

[asavage]

If this works you won't be able to create antigravity fields. Antigravity would require canceling out the very powerful static gravitoelctric field and superconductors have no effect on these fields.

Re:Note that it can't generate antigravity fields

[Chris Burke]

Unless you are a particularly famous physicist posting Anonymously, I'll have to say I question whether you actually came up with that solution to the paradox on your own. Which isn't so much to say that I don't believe as that I heard that explanation for this phenomenon about five years ago or more.

Though regardless, once you know of this explanation, it seems totally obvious. Though really, I think you could just explain it by saying that more sensitive receivers mean signals don't have to be broadcast as far, and thus are going to be harder to detect against interstellar noise. A civilization doesn't need physics to invent a new form of communication to prevent themselves from being detected; they just need to apply a few decades of engineering to the problem of efficient radio. By this argument, we may already be undetectable to any distant civilization that might be searching.

Re:Note that it can't generate antigravity fields

[Chris Burke]

Which isn't to say that I don't think using electrically-controlled graviton waves as a method of communication isn't cool. :)

Re:Note that it can't generate antigravity fields

[hagardtroll]

Yeah, but then the FCC would just come in and regulate the gravitational spectrum, sell it to the highest bidder and japan would come out with all these cheap baby monitors that communicate with gravity waves tying up the spectrum.

Re:Note that it can't generate antigravity fields

[ahde]

Newton and Liebnitz didn't invent calculus independently either. And famous physicists are too bloody inventive these days. Not in physics, at least.

I'll believe it when I see it.

[Cyberdeck]

Extrordinary claims need extrordinary proof. Build the device and demonstrate that it works. Publish the specs. Have other people who are not associated at all with you build these devices. If they confirm the results then the claim can be made relatively authoritatively.

If it doesn't happen then that's also fine, it means that a hypothesis was shown to be not an accurate model of how the universe works.

The method described is science in action, the way it is supposed to work.

Of course if this does work then they are going to have some surprises when they enable those underground superconductive power cables in, IIRC, downtown Chicago. (Detroit? Somebody help me out here, please?)

-C

Re:I'll believe it when I see it.

[God! Awful]

Extrordinary claims need extrordinary proof. Build the device and demonstrate that it works. Publish the specs. Have other people who are not associated at all with you build these devices. If they confirm the results then the claim can be made relatively authoritatively. If it doesn't happen then that's also fine, it means that a hypothesis was shown to be not an accurate model of how the universe works. The method described is science in action, the way it is supposed to work.

Of course the way science really works is that the 99% of people who propose kooky ideas like this, and who don't work for a university, get labelled as cranks while this guy gets recognition and publicity based solely on some back of the envelope speculation.

-a

Re:I'll believe it when I see it.

[Anonymous Coward]

Extrordinary claims need extrordinary proof.

God I get sick of hearing that. Given that we know that current scientific models inevitably get overturned for new ones, and given that a claim can only be considered extraordinary (a judgment on the claim) from within a given scientific model (ie it seems to defy it, or seems very improbable within it), why should extraordinary claims be held to a higher standard of proof? Why can't *all* claims be held to an equally high standard?

Re:I'll believe it when I see it.

[Anonymous Coward]

That's right!
Fuck the Hypothesis!
The Scientific Method is for losers with too much time on thier hands!

Re:I'll believe it when I see it.

[GooseKirk]

Because the phrase "extraordinary proof" is stupid. What the fuck IS "extraordinary" proof? Since when is proof not enough to prove something?

Re:I'll believe it when I see it.

[kevlar]

Very true. Unfortunately though, even some PhD's fail to actually utilize the scientific method when conducting their research. Its all about where they'll get their next round of grants from...

Re:I'll believe it when I see it.

[p3d0]

Carl Sagan's original quote was that "extraordinary claims require extraordinary evidence".

Re:I'll believe it when I see it.

[aallan]

...the method described is science in action, the way it is supposed to work.

No, actually this isn't how things work these days. Science has become so specialised that there are very, very, few people that can do both theoretically and experiemental work at the cutting edge.

Most of us have a fairly good knowledge of a very small corner of one field, a slightly less good knowledge of the entire field, and an educated layman's knowledge of the rest of our discipline. Outside of our own discipline our knowledge is fairly scanty, most physicist's knowledge of chemisty for instance is probably no better than your average layman.

It's just not possible to keep up with everything even in your own field anymore.

The characteristic of bogus (or "junk") science is theories that give predictions that are untestable, or theories that predict things that have already been proved experimentally to be untrue.

While I haven't read the paper, not alot of point as I'm not a quatumn physicist, and my knowledge of quatumn field theory is fairly basic, this guy seems to have made predictions which are provable. This is good science. Whether he is right or wrong is imaterial (to the scientific process), his theory is interesting enough that some experimentalist will pick this up and run with and then we'll find out whether the theory is correct (or not).

Just because he hasn't provided extrordinary proof, doesn't mean that he's doing bad science.

Al.

Re:I'll believe it when I see it.

[Zathrus]

It's not rocket science.

Of course not.

It's quantum mechanics.

Duh.

Re:I'll believe it when I see it.

[pythorlh]

OK...I'm not disagreeing with the general tone of your post, but this part:

. Outside of our own discipline our knowledge is fairly scanty, most physicist's knowledge of chemisty for instance is probably no better than your average layman.

I think you're a tad bit optomistic about that. In the US, the average layman's knowledge of chemistry does not even include how to spell it, much less anything else. I assume that you (and most physicists) could recognise a periodic table of the elements, and even explain what most, if not all of the reference numbers on it refer to. An average layman is more likely to to describe it as "a map of the country. But it looks kinda funny...is that really where Californium is? I thought it was out west!"

Re:I'll believe it when I see it.

[gorilla]

Because some claims are trivial, and we can't spend enough time to validate every claim at the level required to validate the extrordianary ones. If I claim that I've found a fossil of a new species of dinosaur, then that can be validated simply by publishing a description of the fossil. If I claim that I've found a living dinosaur, then I'm going to have to do a little more than just write about it.

Re:I'll believe it when I see it.

[hubie]

Of course there are varying degrees of "proof." For instance, if you are looking for a blip in your data there is a big difference between something like a 1.5-sigma feature verses a 5-sigma feature.

On the other hand, I am not partial to the phrase "extraordinary proof" either.

Re:I'll believe it when I see it.

[osgeek]

I say that the bright orb in the night sky is the Moon, a naturally formed heavenly body to which we've sent astronauts.

Some other guy says that it's really an alien space ship, and that the "Sea of Tranquility" is just a big lens used to spy on us.

My claim is considered "ordinary" because there already exists "extraordinary" evidence for it. The other guy's claim is considered to be extraordinary because there's no real evidence for his claim.

So if you think about it, every theory requires a great deal evidence for it to be accepted as fact.

Re:I'll believe it when I see it.

[Sklivvz]

gravity isn't a force

GR says that gravity is an apparent force which comes out of the bending of spacetime. On the other hand, gravity IS a force according to quantum theory. The whole paper we're discussing treats gravity as a field (author calculates Laplacian and Hamiltonian to derive the coupling). Hence my reasoning. Of course if gravity is NOT a force, but the others are, then you can say goodbye to most unified theories, which sounds wrong to me (Einstein would agree with me on this ;-)

Re:I'll believe it when I see it.

[hubie]

Actually the General Theory was published in 1915. The results immediately agreed with the observations of the perturbations in the orbit of Mercury. It was subsequently verified against a solar eclipse in 1919 (there was an earlier eclipse, but WWI prevented a scientific expedition to view it).

Re:I'll believe it when I see it.

[Nindalf]

Of course the way science really works is that the 99% of people who propose kooky ideas like this, and who don't work for a university, get labelled as cranks while this guy gets recognition and publicity based solely on some back of the envelope speculation.

So?

Those 99% propose kooky ideas with blatant errors in their math and misunderstandings of the previous theories they intend to overturn.

An interesting possibility expressed well is worth something. Incoherent rambling about a random thought is worth nothing.

Some of the most successful scientists and mathematicians were first published before ever setting foot in a university. They just don't stay outside of one for long.

Re:I'll believe it when I see it.

[SIGFPE]

A proof is a proof is a proof. A proof is something that convinces someone that something is true. What is an 'extraordinary' proof? One using surprising methods? One that you didn't expect? One written in a pretty font? If it convinces it convinces. Whether it's extraordinary or not is completely irrelevant. There are no degrees of proof. Either it is a proof or it isn't.

Laws of Motion

Something makes me think that if I were to call your bluff you'd have no idea what these so called 'Laws of Motion' are.

Re:I'll believe it when I see it.

[ahde]

"extraordinary proof" means something besides a stupid writeup in a club magazine. Most scientific "proofs" these days are nothing more than pieces of paper with ink on them that speculation about impossible conditions in nonexistent space with false math that are not observable but may exist (or be incorporated into a science fiction novel) sometime in the future.

By extraordinary proof, they mean "at least some tiny shred of evidence." By which the poster means, it's not possible, and the club magazines sucks these days because the sci-fi has no characterization or plot.

Mmm... Time machine

[ObviousGuy]

Maybe they'll go back and rename the school correctly. Berkel. It is to laugh!

As for the theory, it doesn't seem plausible, but physics is full of implausible concepts that work out in real life. Since gravity is a manifestation of a warpage of space-time, does this also mean that he is claiming superconductors are equivalent to gravity wells?

No doubt that the symmetry between Maxwell's equations and Einstein's equations is stark, but does this also mean that they are equivalent in meaning and applicability? Though the article puts a dig into superstring theory at the end, isn't it exactly this type of theory that is needed to unify such disparate theories as gravity and electromagnetism? If there is a symmetry there, wouldn't it make sense that the two equations would derive from a common principle?

My elementary physics is no match for the mathematics in the paper.

Re:Mmm... Time machine

[sconeu]

No doubt that the symmetry between Maxwell's equations and Einstein's equations is stark, but does this also mean that they are equivalent in meaning and applicability?

If superstring theory is correct, then they've been known to be equivalent since the 1920s. The Kaluza-Klein equations show that in a 5-dimensional space-time (4xspace + 1xtime) or higher, Einstein's equations and Maxwell's equations both come out. See Kaku's Hyperspace for more info.

Re:Mmm... Time machine

[NewtonsLaw]

Since gravity is a manifestation of a warpage of space-time, does this also mean that he is claiming superconductors are equivalent to gravity wells?

Cause or effect?

Does mass produce gravity that produces a distortion in space-time..

or is it a distortion in space-time that produces the illusion of the gravity associated with a mass?

Can we exceed the speed of light? Of course we can -- just combine the theories of Einstein with the observations of Gallileo...

Einstein tells us that the mass of an object increases infinitely as we approach the speed of light. This has been taken by most to mean that accelerating a mass beyond the speed of light would therefore require infinite energy.

But hang on -- Gallileo correctly determined that the acceleration of an object when acted on by a gravitational field is independent of its mass (air resistance not withstanding).

So -- if we use an external gravitational field to accelerate an object, the fact that it will gain infinite mass is irrelevant -- because it will maintain the same acceleration regardless.

Hence -- black holes and their immense gravitational pull are our secret to faster-than-light travel.

Now if I could just hitch one up to my mountain bike I'd be away :-)

Re:Mmm... Time machine

[s390]

Maybe they'll go back and rename the school correctly. Berkel. It is to laugh!

Surely. Isn't it properly spelled "Berzerkely?" ;-)

As for the theory, it doesn't seem plausible, but physics is full of implausible concepts that work out in real life.

True enough. Yet the more implausible they seem, the more I suspect them of being over-convoluted theories that just _happen_ to match the results. Some things that seem implausible from a macro (visible, Newtonian) point of view are believable, but a lot of the quantum-level theories are just guesswork, as far as I'm concerned. Physicists must publish _something_ to keep their jobs, and that's what I think drives too much of the recent scientific theorizing. Publish something! That's their bread and butter. And they can write up for grants to pursue Big Physics research... and jobs. For example, fusion research is all simply a massive boondoggle.

Since gravity is a manifestation of a warpage of space-time, does this also mean that he is claiming superconductors are equivalent to gravity wells?

Another interpretation is that the space-time warp of gravity is a big illusion... that gravity isn't about mass but about energy (and mass and energy are related, thus the illusion). Thus the photons which have no mass _do_ have its analog... energy, and thats what gravity acts upon to bend the path. There _must_ be a consistent explanation for both macro and quantum level interactions, and until we find it, we'll not be intellectually fit to travel into the cosmos. We've got time (depending on when the next major comet intersects Earth's orbit at the wrong moment), but we do really need to figure everything out before our time runs out for us here.

No doubt that the symmetry between Maxwell's equations and Einstein's equations is stark, but does this also mean that they are equivalent in meaning and applicability?

My intuition tells me that such mathematical symmetries are trying to tell us something, but we just haven't figured it all out well enough - yet. We need free thinkers in the physical sciences, but... the entire structure of academia is built to enforce conformity. Some few people survive it and think "outside the box" as it were (Feynmann comes to mind), but the majority are just buried in conformity. The best thing the politicians could do to advance science would be to grant all science graduate students Associate level pay with no obligations to serve their tenured colleagues, but maintaining their freedom to consult and even collaborate with them whenever they find it helpful. This would accelerate big science in a way that would make the last decades seem a backwater.

Though the article puts a dig into superstring theory at the end, isn't it exactly this type of theory that is needed to unify such disparate theories as gravity and electromagnetism? If there is a symmetry there, wouldn't it make sense that the two equations would derive from a common principle?

Yes. Superstring theories (there are several that are trying to agree, convolutedly) are all so very complex that they're ultimately not very credible. Sorry! (To a generation of theoretical physicists.) The Universe _must_ have some simple rules (Einstein would agree with this, I am sure), but you haven't figured them out, so far. Complex systems are the products of insufficient mentality in both science and large-scale software systems. The bottom line for me is that I'm not convinced that they're not just playing with irrelevant and really fantastic math that will never work right. When they go outside five dimensions (3 space, 1 time, 1 energy), I lose interest. Or maybe six (vector/spin). But you maybe will get my drift... ten, twelve, fourteen dimensions? Give it up already!

My elementary physics is no match for the mathematics in the paper.

Mine too. ;-) But my scientific intuition is not satisfied by the embarrassing worldwide failure to integrate General Relativity with the Standard Model of Quantum Theory. It's an intellectual debacle that the so-called "best minds" of science haven't been able to work this out for going on a century here. It's also a shame that kids aren't going into science. Can we rehabilitate the Red Menace to get our politicians and educators back in gear here? That worked real well in the 50s and 60s, but raghead terrorists won't cut it.

Re:Mmm... Time machine

[raistlinne]

"The Universe _must_ have some simple rules"

Why? This is a most extraordinary claim. Are you prepared to produce your extraordinary evidence?

Oh, and a quote from Einstein that I rather like, ""Everything should be made as simple as possible, but not simpler."

"When they go outside five dimensions (3 space, 1 time, 1 energy), I lose interest."

It's funny: when I read this I got a mental picture of a race of blind people discussing physics and introducing this bizarre concept of "energy waves" that travel around, and people getting bored by it because it's obviously just an overly complex theory being shoe-horned onto reality.

Do you have any evidence, or even any reason to believe, that there are in fact not seventeen dimensions and we just don't have the necessary organs to readily percieve them all as being distinct?

Bear in mind that without sight or our kinesthetic sense, there would be no especially good or convincing way to tell that space had 3 dimensions to it.

Btw, when the view that you are currently advancing was put forth on some other topic a few weeks ago, a name for was mentioned that seems highly appropriate: "proof by instant gratification". How do you maintain it with a straight face?

Re:Mmm... Time machine

[s390]

Do you have any evidence, or even any reason to believe, that there are in fact not seventeen dimensions and we just don't have the necessary organs to readily percieve them all as being distinct?

Do you have any evidence or reason to believe that there's not an _infinite_ number of dimensions? Why not? If you accept (with _no_ supporting evidence) 10 or 12 or 14 dimensions, why not go for 10,000 or so dimensions, or 10**80 or so dimensions. It makes no difference! It's all just imaginary, just conveniently approximate math to justify what the so-called "scientists" do with large amounts of public moneys, which they waste.

I'm no Luddite (a step-daughter did theoretical quantum physics until she transferred into astrophysics last year), but I'm skeptical.

Re:Mmm... Time machine

[Sklivvz]

Do you have any evidence or reason to believe that there's not an _infinite_ number of dimensions?

Well, you seem to forget the reason why those extra dimensions were put in string theory! The K-K equations show that adding an extra (curled up) dimension makes EM a consequence of GR. So, in simple terms, you do see the extra dimension, but you "measure" it as EM charge. The other dimensions are added up to provide for the other charges (i.e. weak and strong charges). Is that so strange? Not to me, not stranger than allowing for phantomatic "charges" (what is EM charge made of?).

So basically, we don't have an infinite number of dimensions because we don't have an infinite number of different possible charges.

Re:Mmm... Time machine

[s390]

(Great sig you have - what does it really say?)

See Occams Razor (the original statement, much abused since), which was roughly "Don't multiply entities beyond necessity."

To me, that translates to deprecate imaginary dimensions in quantum mechanics, beyond necessity. Necessary means observable.

To me, superstring theory is just too fantasical to stand. Sorry, Hawking, et al. I don't buy it, the Universe doesn't work like that.

I think we ought to demote most of the physicists in academia to teaching positions - no "research" for about 5 years or so. Then let students loose on the issues, but with none of that former apprenticeship culture that has held back several generations of scientists.

Re:Mmm... Time machine

[raistlinne]

Do you have any evidence or reason to believe that there's not an _infinite_ number of dimensions?

Nope. There might be. Can you provide some reason to believe why there aren't? Until you can provide some reason to believe that there are in fact only 3 (or 4, or whatever exactly it is that you believe in), why do you go on about how nonsensical talking about 5 or 6 dimensions is?

Human knowledge is currently fairly limited. Why do you insist on speaking as if it weren't?

Re:Mmm... Time machine

[Dirtside]

The traditional interpretation of Occam's Razor is that if you have two equally useful explanations for something, the simpler one is more likely to be correct.

The problem with your statement is that there isn't another theory that's equally useful to superstring theory. Even though superstring theory is a lot more complicated than other theories, it also explains things a lot better. Occam's Razor doesn't really apply.

The way I see you looking at it, it appears that you're saying, "Well, superstring theory seems really complicated... too complicated for my tastes. Hence, I'll reject it." This is generally a bad idea when it comes to scientific hypotheses or theories.

Re:Mmm... Time machine

[s390]

The way I see you looking at it, it appears that you're saying, "Well, superstring theory seems really complicated... too complicated for my tastes. Hence, I'll reject it." This is generally a bad idea when it comes to scientific hypotheses or theories.

Well, this thread is getting stale, but let me respond anyway. (I couldn't care less about the karma hits -- sitting at 50 is boring and Slashdot should raise the cap to 100, perhaps with a net plus rating on a post only raising karma by a +1... or something like that).

Yes, I'm arguing against overly complex theories to explain physical reality. Though I'm not sure I agree with Wolfram and his cellular automata analogies, I think they're interesting and worth some thought and exploration. Too bad he's so self-centered....

Simplicity is very compelling, whereas complexity is the enemy of any efficiency -- and the Universe is nothing if not extremely efficient. While I'm not near ready to agree with Wolfram that the laws of the Universe are "four lines of code," I'd also welcome this if turned out to be the case. Simple is a cardinal virtue, when it comes to fundamental physics, at least in my iconoclast book.

The fundamental issue is that General Relativity (GR) doesn't intersect with Quantum Mechanics (QM) whether QM is represented by the (lately dubious) Standard Model (SM) or some variety of Superstring Theory (ST) -- of which there are several competing flavors. My objection is that they are all too complex, and that they don't resolve the basic problem of accounting for GR gravity! Maybe someone well versed in ST might convince me that they have it covered, but I haven't seen that yet. Any better theories?

Sorry, no anti-grav

[sequence_man]

All he is exccluding are gravity-waves. These are different then the basic curvature of space that generates gravity itself. Basically they are little ripples that float on top of the curvature. So blocking them won't levitate us.

Re:Sorry, no anti-grav

[beanyk]

All he is exccluding are gravity-waves. These are different then the basic curvature of space that generates gravity itself.

If you mean "gravitational waves", then no, they are *not* different from the curvature of space. It's exactly the same stuff, though gravitational waves passing close to the Earth are probably very weak.So yes, they look like ripples on our pretty flat curvature, but they're just smaller-scale, generally weak curvature perturbations on a much more uniform background curvature.

As an aside, the term "gravity wave" is usually taken to mean "wave formed by a process where gravity is significant", like some types of water wave. Not actually what's been talked about here.

Re:Sorry, no anti-grav

[Lerc]

I want my zero-G sauna, dammit

Uh dude, can you get a velco towel like the rest of us? It's doing that thing again.

Re:Sorry, no anti-grav

[osgeek]

Ya know, so very little is understood about the underlying nature of gravity. We don't know if there is an associated particle that plays a roll in a gravitational field. We don't even have a basic understanding of how gravity interacts with mass.

Given that lack of knowledge, your statement is really no more than just a shot from the hip (a guess based on your intuition).

This has been around.

[Max Threshold]

Isn't this just a new take on the Podkletnov effect?

Re:This has been around.

[Vireo]

Isn't this just a new take on the Podkletnov effect?

Excerpt of the article in the paper version of SciAm:

(...) Even if Chiao's contraption works, it wouldn't allow the generation of antigravity fields, as Russian materials scientist Eugene Podkletnov, then at Tampere University of Technology in Finland, controversially claimed to have observed in 1992. (...)

Sigh...cynicism kills!

[DaBjork]

Firstly, Fuel cells ARE 8th grade chem, they are just 2H + O = H2O. Secondly, astrophysicists have been theorizing antigravitation as a solution to the "dark matter" problem for quite sometime. Don't get me wrong, I am all for a healthy dose of cynicism, but in order to progress we need to take an open mind. This is not that far out of the realm of possibility. Point to the error in the theory if you feel this person is wrong. Then your point will stand on it's own.

Re:Sigh...cynicism kills!

[prockcore]

"I am all for a healthy dose of cynicism, but in order to progress we need to take an open mind."

Not necessarily.. you should clarify that to *scientists willing to do the research* need to have an open mind. The rest of us can go along with "believe it when I can buy it for $49.95 at Wal*Mart" stance and the world will be just fine.

My not believing (or understanding for that matter) that this stuff works, doesn't have any impact on the future at all :)

Re:Sigh...cynicism kills!

[MulluskO]

I can buy it for $49.95 at Wal*Mart" stance

You'll be seeing this at the Sharper Image.

"Dude! You have a computer game in your bag. My computer has a built-in mouse and this game with goblins. You gotta burn me a copy of that on CD! You suck!"
-Orange-haired employee at the Sharper Image(2 months ago).

Re:Sigh...cynicism kills!

[dillon_rinker]

At the anode the hydrogen molecules give up electrons and form hydrogen ions, a process which is made possible by the platinum catalyst.

And don't forget...hydrogen ions are raw protons, their positive electrical charge unmediated by electrons...

If it sounds too good to be true...

[PurpleFloyd]

Note that the Scientific American article is very cautious: they state the implications if it's true. While, if true, this is a breakthrough on the level of relativity or quantum mechanics, one should take this with a large grain of salt. Plenty of other "revolutionary" theories haven't managed to pan out.

This was in wired a while back

[miahrogers]

This was also in wired about 5 years ago, you can find it here.

Why don't superconductors weigh less?

[khym]

If a superconductor will float in a static magnetic field, why won't it weigh less in a static gravitational field? If it did, they wouldn't have to go throug elaborate tests to verify the theory.

Re:Why don't superconductors weigh less?

[PatientZero]

The weight of an object is precisely the force acting on it resulting from a gravitational field. When the superconducter levitates in a magnetic field, it still weighs the same as neither its mass nor the gravitational field have changed. Instead, the magnetic field applies a force on the superconducter that is larger than the gravitational force.

Similarly, a plane in flight still weighs the same, but the air moving across its wings applies an equal upward force, keeping it aloft.

Re:Why don't superconductors weigh less?

[khym]

Yes, force applied by gravity on a superconductor doesn't change when it's put in a strong magnetic field. But if a superconductor can do the same thing to gravitational fields as magneticc fields (repulse them), then wouldn't there be less gravity acting on a superconductor than an ordinary conductor?

Re:Why don't superconductors weigh less?

[dragons_flight]

Ordinary gravitational attraction is dominated by "gravito-electric" force, or in normal language the force generated by stationary masses. In everyday concerns the Earth is the only mass that matters and it is stationary to a good approximation for nearly everything humans do.

The paper talks solely in terms of affecting "gravito-magnetic" forces, which are those exhibited by moving masses (and generally only significant among masses moving at an appreciable fraction of the speed of light). Simply put there just isn't enough gravito-magnetic force in every day life to notice any change. If there were an appreciable gravito-magnetic force in ordinary everyday gravity then yes you could test it, though I'm not clear how to expect it to react.

To put things another way, Newton described gravity purely in gravito-electric terms and most of us will never notice the more complex gravitiational interactions that Einstein discovered and this physicist cares about.

Re:Why don't superconductors weigh less?

[PatientZero]

It's been a long time since I did this (1988), but in my senior year of high school a couple friends and I made a superconductor with our physics teacher. With it we successfully reproduced magnetic levitation via the Meissner Effect: "If a small magnet is brought near a superconductor, it will be repelled becaused induced supercurrents will produce mirror images of each pole. If a small permanent magnet is placed above a superconductor, it can be levitated by this repulsive force."

Thus, the superconductor is not affecting the gravitational field. It is in a sense becoming a magnet itself, producing an exact-opposite magnetic field. This new field simply repels the magnet, producing levitation. By far the coolest effect was spinning/flipping the magnet over the superconductor and having it remain levitated, as the superconductor's magnetic field was always a mirror of the magnet's.

Now, in this I am not talking about the article or paper (I just started reading it). I'm simply talking about the magnetic field that is induced in a superconductor by magnets. My only experience and knowledge of the subject was the experiment in high school.

Re:Why don't superconductors weigh less?

[Christopher Thomas]

Aren't the Coriolis force and the gyroscopic effect somehow related to "gravito-magnetic" forces ?

No, they're just consequences of Newton's laws of motion.

Coriolis effect is the result of you (or a thrown object) trying to move in a straight line while your point of view rotates.

Gyroscopic effects are the result of conservation of momentum in the flywheel (to change the axis of rotation, you have to apply a torque that makes up for the change in angular momentum).

Podkletnov

[g4dget]

I'm surprised he doesn't have any references to the Podkletnov and Woodward effects.

In any case, I'm not sure I believe any of this, but I think it's good that there are people thinking outside the mainstream.

Re:Podkletnov

[big_hairy_mama]

Maybe he thinks, like most of us do, that Podkletnov is a crackpot, and he wants to dissasociate himself as much as possible.

Re:Podkletnov

[g4dget]

This is science, not a sandbox brawl. You don't get to pick and choose who you cite based on who you don't like. Podkletnov's experimental results are published, peer reviewed, and seem related. If Chiao is aware of them (and he must be), he has an obligation to cite them. If he thinks Podkletnov's results have no bearing on the effects predicted by his own theory, he can explain so in his citation. If he thinks there are fundamental flaws with Pokletnov's experimental setup, he can explain them.

Personally, I think both are crackpots. But if crackpots publish scientific papers, they still should follow the rules of academic conduct, because the rules of academic conduct ultimately are what helps us sort out the real crackpots from the forward thinkers.

Re:Podkletnov

[rsidd]

Personally, I think both are crackpots.

Why do you think Chiao is a crackpot? Have you even read his paper?

Podkletnov's experimental results are published, peer reviewed, and seem related.

But they aren't related. They suggest a screening of a static gravitational field, what Chiao calls a "gravitoelectric" field, which is what we observe in everyday life. As Chiao points out, it's impossible to screen such a field within the setup of standard gravity theory, because (as far as we know) only positive masses exist and they can't cancel. (Equation 34 in his paper, keeping in mind that the mass density is always positive. The only way you could produce a static cancelling field is from Equation 35 with a linearly increasing gravitomagnetic field, which again is not a static solution and not a useful idea.)

What Chiao is talking about is the screening of the "gravitomagnetic" field, which is something we do not observe at all in daily life, but should exist according to Einstein's equations. He's not focussing on magnetostatic flux expulsion either (like the Meissner effect) but about some dynamic effect on gravity waves. This, he claims, would lead to a measurable effect. (I find that astonishing, since the effect comes from electrons which have a really tiny mass). If he can prove it experimentally, it will indeed be huge. But it has nothing to do with Podkletnov's claims and I don't think he's obliged to cite them at all.

Re:Podkletnov

[Bearpaw]

This is science, not a sandbox brawl. You don't get to pick and choose who you cite based on who you don't like.

[cough] Well, um, actually ... that sometimes happens. That's rarely the only consideration, true, but personal loyalties and hostilities and such do actually play a role in real-world science.

Re:Podkletnov

[hubie]

You are not required to cite work that the original author retracted. In most (but not all) cases it would be silly to.

In fact, in Podkletnov's case he withdrew his paper before it went up for peer review, so it was never published and hence there is nothing to cite. If he later did resubmit to a peer reviewed journal than please provide the reference as I would be interested to see it.

Re:Podkletnov

[jaoswald]

You praise crackpots rather glibly. In order to support "often" you ought to be able to name more than one example of a crackpot ending up with a valid contribution to physics from his crackpottery.

To save time, I'll say right off that Newton and Einstein were never crackpots. Einstein's most vocal opponents, however, were. Also, Tesla did not make a major contribution to physics, although he may have ended up a crackpot.

Re:Podkletnov

[g4dget]

Why do you think Chiao is a crackpot? Have you even read his paper?

As far as I can tell, Chiao's paper is pure speculation. If it doesn't work, it wouldn't falsify any of our current physical theories, it merely means that one of Chiao's guesses or assumptions is wrong.

I think both kinds of work are out on the fringe (which is what I mean by echoing the word "crackpot"). Both really just need more credible experimental evidence before one can take them seriously.

They suggest a screening of a static gravitational field, what Chiao calls a "gravitoelectric" field, which is what we observe in everyday life. [...] But it has nothing to do with Podkletnov's claims and I don't think he's obliged to cite them at all.

There are maybe a handful of published papers that claim observation gravitational effects from superconductivity. I think it's appropriate to mention them, even if it is just to make the point you did. (And if Podkletnov's effect were real, perhaps it could be explained using mechanisms other than shielding.)

superconducters

[DaBjork]

I might add after perusing the comments a little about superconductors. First off, liquid nitrogen is not a magic and impossible to find substance. it is cheap and easy to acquire as far as gasses go. Secondly, the city of Chicago has been using superconductors in their power grid for around 2 years. Supposedly the main line carries something on the order of 10s of thousands of amps (I belive 16,000 but I am not sure). Just for scale, you be hard pressed to find a house with any plugs rated above 20 amps, the nuclear structure lab I work at has some lines with 50 amps, but none higher.

Re:superconducters

[Prior Restraint]

[Nitrogen] is cheap and easy to acquire as far as gasses go.

I have some nitrogen for sale, if you'd like. Fair warning, though: it's a little contaminated. I think it's only about 75%-80% pure.

Not the first time...

[Archie Steel]

...somebody claims this. IIRC, someone in the early 80s had claimed to have done this (with "Radio Shack" parts) - I wish I remember where I read this - and of course there's Podkletnov, though the jury's still out on whether it was a hoax or not. Mind you, NASA has its own programme researching this...I'd be curious to hear their take on the issue.

IF this pans out ... :)

[ProfMoriarty]

Where do we donate to erect a statute of him in Montana?

BTW, I've noticed a disturbing trend of really smart people != me ...

Wait for the experimental test

[Animats]

The key point here is that the theory predicts that the conversion of microwaves to gravity waves will be reasonably efficient. So this is testable, and is being tested. There should be a definitive result this year.

Nobel prize material if it works. Footnote in Physical Review Letters if it doesn't.

Re:Wait for the experimental test

[nihilogos]

The key point here is that the theory predicts that the conversion of microwaves to gravity waves will be reasonably efficient. So this is testable, and is being tested.

How? Are they actually *detecting* gravity waves?

Re:Wait for the experimental test

[Wocko]

It is based on the fact that not only should gravity waves convert to microwaves, but that the inverse should be true.

So, if you imagine the following experiment:

Inside a Faraday cage, place a superconductor and a microwave source.

Inside another Faraday cage, place a superconductor and a microwave detector.

From inside the first Faraday cage, fire the microwave source at the superconductor. The theory predicts that a gravitation wave will be emitted.

Aim the (suspected) emitted gravitation wave at the second superconductor (inside the second Faraday cage).

Detect any microwave radiation after the gravitation wave has been converted by the second superconductor.

The Faraday cages block electromagnetic radiation so they ensure that no microwaves can leak from the emitter to the detector, and therefore gravitation waves must be the culprit.

Re:Wait for the experimental test

[kevlar]

Wow... maybe you should be reviewing one of those physical journals...

Re:Wait for the experimental test

[FuzzyDaddy]

This is absolutely right. I was a physics grad student at Berkeley when I first heard about this idea. The excitement was not about antigravity, but about producing and detecting gravitational waves. The predicted coupling of gravitational waves to matter is very weak, and experiments to date (using very large block cooled to very low temperatures, and looking for vibrations) have been inconclusive. Their extistence is pretty well confirmed by the observation, over a long period of time, of the decay in the orbits of a binary star system. (Two people from Princeton won the Nobel prize for this, but I've forgotten who and when). Chiao's idea was that a superfluid would move instaneously, because it was a single quantum state. His proposed experiment is exactely as Wocko describes, and is a version of the classic experiment which detected electomagnetic radiation. If you're into pie-in-the-sky application possibilities, imaging wireless communications, except because the wave interacts so weakly with matter, there is almost no interference from intervening matter or other radiation sources. Sort of like ELF except with some real bandwidth.

Re:Wait for the experimental test

[Illserve]

There's surely better ways to test this theory. Any positive result could be the result of rebounding microwaves or a defective cage. How about simply detecting the gravity waves directly by looking for minute deflections of an object?

Re:Wait for the experimental test

[ocie]

If this were the case, wouldn't the Earth's gravity cause the semiconductors to emit microwaves?

Re:Wait for the experimental test

[Broccolist]

I'm not a physicist, but my understanding is that the Earth's gravity exerts a constant force --- but not a wave, which is a cyclic variation of force.

As an analogy, consider sound waves, which are variations of air pressure. As you know, on Earth there is a constant air pressure of (IIRC) ~100 kPa. One might expect, by your logic, that we would hear a permanent blast of noise even in an empty room. We don't: the point is that sound consists of changes in air pressure, not the pressure itself. Analogously, according to this theory, only fluctuations in gravity (i.e. waves) would cause microwaves to be emitted. The unchanging force of Earth's gravity would do nothing.

Someone correct me if I'm wrong.

Re:Wait for the experimental test

[anonymous loser]

Ok, so that means that semiconductors (actually, I believe the original poster meant superconductors) should emit microwaves as they move through a gravitational field.

podkletnov

[prell]

this observation was made years back by a scientist named podkletnov in Europe (hey, I said it was a while ago ;-). He used a super-cooled YBCO (yttrium boron carbon oxygen I believe) superconductor and was able to "reduce the mass of" (ie affect the gravitational effect on) objects. They actually ran an article in wired on him way back when (96-98 sometime). The "gravity society" had a website at www.gravity.org, but currently I cant reach it.

Re:Thats one camp

[lucifuge31337]

What else weighs that same as a duck?

not yet antigravity

[Anonymous Coward]

First of all, he's talking about blocking "gravitomagnetic" fields, which if I understand correctly you get from moving masses. So the static gravitational effect from e.g. the Earth isn't blocked.

If what he claims is true then first of all he has invented a great new way to emit and detect gravitational waves. It would be awesome for astronomy, useful for submarine communication (and maybe detection), and probably many other things. However, it's not immediately obvious that we're talking "antigravity" here, so don't get too excited.

Also keep in mind that 99+ times out of 100 these sorts of claims are completely bogus and a waste of time. Just sit tight and wait for rebuttals or confirmation to appear on the LLNL server.

Re:Temperature is a hurdle

[Chris Coster]

Correct, but that doesn't mean that they haven't already found significant commercial applications (more than once ) in the real world.

Re:Ginger 2....now this is IT ;)

[Yorrike]

Time to start getting my skills up so I can enter the F-Zero or Wipeout leagues. This innovation will bring about nothing but high speed, heavily armed hover craft racing.

Military applications

[Alien54]

If this works you won't be able to create antigravity fields.

Not that this wouldn't prevent the usual research into military applications. I wonder how much force is generated, how much enhancement of force is created per megawatt?

Insert visions of UFOs with terrawat gravity generators, using this as a weapon to nuetralize gravity at an area of the surface below them. Enemy troops go drifting off into vaccuum or fall from a substantial height back to the ground.

NB the weather effects as well, of all of that atmosphere going up an anti gravity shaft, creating a storm.

Re:Military applications

[Pig Hogger]

NB the weather effects as well, of all of that atmosphere going up an anti gravity shaft, creating a storm.

Ah, like what happens over a chunk of cavorite...

Re:Military applications

[Alien54]

Are you a flaming retard, or do you just play one on TV?

One Word - Tides

You have a mega UFO above a planet enhancing the gravity field of the UFO itself, thereby lowering the gravity beneath it towards the planet.

The gravity of the UFO pulls things toward it. This slightly reduces the gravity of the earth beneath it pulling things towards the Earth. Enhance this effect, and make sure the the UFO has damn strong engines so as to not get pulled into the planet itself.

Also, Storms are caused by low pressure areas. Reducing the gravity on a spot basis will tend to lower the atmospheric pressure in that one spot. This will at least cause wind as air molecules rise due to the lowered gravity. On a large enough area you'll generate storms.

The point is not to create antigravity by nuetralizing it. The point is to fake antigravity be having something above that is pulling things up using its own gravity beam, or whatever.

with a big enough vehicle, you could probably cause earthquakes as well. Need a mega giga tera watt beam, tho.

I wonder how tight a beam you could get from a thing like this.

I'll grant you that these points is not immediately intuitive.

So you are forgiven as well.

Re:Military applications

[Alien54]

I thought your original criticsm was based on the idea of the antigravity field levitating the UFO.

which it was not.

It was a military use of decreasing the intensity of gravity beneath the UFO by increasing the gravity of the UFO itself.

To be fair, it was not clear that your criticism was based on anything other than the understanding of the my writing, that I thought that the effect generated would create antigravity. which is not what I was visualizing.

After all You did say, " Are you a flaming retard, or do you just play one on TV? The post you responded to -- the exact part you quoted -- was stating that you can't generate anti-gravity fields! ". When I think of an anti gravity field, I see the typical mind experiment UFO lifting off gently into the sky by cutting off gravity, reversing gravity so that it is a thrust, not a pull.

The example I imagine for this discussion was still a pull field, not a push. Thus not a use of an anti-gravity field, but rather a clever use of an artificial gravity field.

On the other hand, this new criticism re: a static field may be valid.

although the thought of a gravity field pulsating in my general direction leaves me feeling a bit quesy. Big enough and slow enough, it could be quite nasty.

Re:Thats one camp

[The Cat]

Bread!
Apples!
Very small rocks
Cider
Mud
Churches!
Lead Lead!

A Duck!

Free Advice for Fringe Physicists

[Corvus9]

A few posters, and Scientific American itself, are skeptical of these claims. This is reasonable, because they are so dramatic.

If Dr. Chiao is worried about his reputation, or getting published, or arguing with critics, I have some free advice: discover first, publicise second.

The article claims "By the time the theory is vetted, though, Chiao will probably have conducted his experiment and settled the question." Wonderful! Wait a few months to actually do the experiment, then publicise it. His reputation will be safe, everyone will want to publish it, and critics can try the experiment themselves. He will probably be able to complete it faster because he won't have all these clueless reporters asking him questions.

But you have to discover it first.

Re:Free Advice for Fringe Physicists

[Saoshyant]

Chiao has published the paper describing the theory, complete with mathematical arguments that "seem to be correct." Now, he's moving on to perform the experiments that will either verify or refute the theory. This is the way it's done! Black Holes were nothing more than a theory with mathematical arguments that "seem(ed) to be correct", until CHANDRA started supplying experimental evidence. General Relativity was a theory with mathermatical aruments that "seem(ed) to be correct", until we managed to observe light bending around the mass of the sun. There's nothing wrong with publishing a theory that has yet to be proven; many theoretical physiscists never participate in experimentation. They publish theories.

Re:Free Advice for Fringe Physicists

[g4dget]

I think it's still an open question whether black holes (singularities in space-time) actually exist. All the current observations are compatible with many different kinds of theories. And there is no experimental evidence available at all, only observational evidence.

Re:Free Advice for Fringe Physicists

[snake_dad]

discover first, publicise second

It is not always the scientist who is responsible for publication. It also happens that university staff hear about some discovery that may or may not be valid, and chat about it during lunch with someone who knows a reporter, who then publishes some wild story. Scientist's career is ruined, but hey, at least we sold a couple more newspapers...

I had a friend once . . .

[Ezubaric]

I had a friend who was working on this for a while. He kept building larger and larger metal units, cooling them down more and more, trying to get a rotating disk to speed up in a very, very, strong (par. magnetic field). If it sped up, then this was a reduction in the moment of inertia, and a decreased effective mass.

After two years of working on it, he gave up. He did get a measurable increase, but it was too little to be more than measurement error.

Re:I had a friend once . . .

[SilverSun]

He did get a measurable increase, but it was too little to be more than measurement error.


Do you realize that your statement does not make any sense? If he got not more than a measurement error could acount for, then he did not get a measurable increase.

Re:I had a friend once . . .

[Elbereth]

I had a friend once, too.

The reverse..?

[PRickard]

Can this work in reverse to create a gravity field? Artificial gravity on the space station, for example. Or doubled/tripled/quad gravity in a lab on earth to test equipment intended for planetary exploration. I'm sure somebody could use that, if it's possible.

That said, I think somebody needs a girlfriend... Or the "The Simpsons" Season 1 Box Set and a DVD player.

Special Relativity doesn't work that way...

[tm2b]

Assuming you're not just trolling/joking, here's the thing:

You don't add velocities linearly in special relativity, they add in such a way that they can never exceed c in any reference frame. In order to move faster than light, you need either a discontinuity or an effect in a domain not covered by SR (GR, quantum, ...).

Special Relativity is a really cool system, but it doesn't act intuitively - it all falls out of the simple assumption that everybody always sees light as moving at c relative to their own reference frame (no matter how fast they are moving).

There's a nice intro to a bunch of the concepts involved here (sorry, requires flash).

This might answer some questions...

[RyanFenton]

Note: I'm not especially expecting this to be true, just wondering what it would mean if it WERE true. I'm also just a computer science student, and am acting more as a philosopher than a scientist proper.

If it were true that gravity can be "generated" from matter by setting it up in a special super-conductive state, then sending energy at it, then we could learn several things.

First, we could learn if gravity is faster than the speed of light. This also means that faster-than-light communication would be possible, and eventually a form of faster-than-light information-conversion-based travel.

In addition, a new form of travel may be possible by just sending a small gravity generator where you expect to go, and have the smaller object pull you towards your destination at a cheaper net fuel cost. There's a LOT of assumptions here though, and the very idea itself seems to go against many principles of energy conservation.

It would also mean that humanity would have an interesting opportunity to attract matter, and eventually counter the effects of universal expansion.

Through learning about the speed of gravity, if we find that it is "instant", it may be possible to learn the time scale of the universe.

We may also learn of the nature of the range and shape of gravity over distance. Things such as if it travels as waves that may miss particles, and if there are "weak" spots in it's eminations relative to the polls of an atom, and how often these waves may be emitted if they exist as such.

Of course, nothing says that even if this were true, that it would be in any way efficient to use energy to generate gravity. Perhaps there is no way we could even generate gravity fast enough through energy conversion to match the effects of a marshmellow. Or much worse, perhaps it would be ironically simple to make a device that would slam a distant asteroid, planet, or star into our world within a few decades of the first exeriment!

So, what else might this mean, either if it is true or false?

:^)

Ryan Fenton

Re:This might answer some questions...

[RyanFenton]

Nah - the 9.81 m/s/s value is just the average acceleration in freefall for an object within a few miles of the surface of the earth, not counting the effects of atmosphere. It's the effect of gravity, not the speed of gravity itself. On heavier planets, this value is generally higher, because more mass is exerting gravity, thus pulling objects faster. Here's a link to a page with one discussion on the speed of gravity I'm talking about:

http://www.ldolphin.org/vanFlandern/gravityspeed.h tml

Again, I'm not acting as a scientist proper in this thread - but the speed of gravity in this context is meant to mean the speed at which the force itself "moves", not the speed at which objects affected by it move. The question essentially is: At what rate does the pull from one mass end up having an effect on another mass' acceleration?

:^)

Ryan Fenton

Re:This might answer some questions...

[dragons_flight]

We already know that gravity propogates at the speed of light to within our ability to measure it's effects (which is reasonably good). Doing so is also a requirement of general relativity.

Re:This might answer some questions...

[dragons_flight]

Let me qualify that by saying the way GR ought to be applied, as opposed to the way it often is. We don't generally propogate gravitional effects as travelling distortions to space time because it is too hard. Instantaneous changes are easier.

Ah

[autopr0n]

You mean like getting energy from the tides?

I'm too stupid...

[buss_error]

..to even pretend to understand this. But this much I know: I'll be keeping those old technology wheels on my car for a while longer. I wonder how long it will be before I can't get any one to work on my car, while they sniff and look down their nose, complaining (whining) "That's OLD technology. Upgrade to anti-grav!"

Not Anti-Gravity

[FatlXception]

If I understand the Scientific American article correctly, what we're talking about here is NOT blocking gravitational fields in the standard sense. The normal, static gravitational effect we associate with massive objects is really a manifestation of the gravitoelectric field. Superconductors, however, are believed to block the gravitomagnetic field, which occurs when a massive object is in motion or rotating. This is also referred to as the Meissner effect, or "frame-dragging". Note the effect of earth's gravitomagnetic field is very small; physicists have only barely been able to prove its existence based on minor course corrections needed for satellites in earth orbit, where the earth is the massive rotating object. So no, the effect of superconductors on gravity (if true at all), will not directly lead to hover technology. What it might lead to is a better method of detecting and generating gravitational waves; in theory, such waves could someday be used for communication the way EM waves are today.

Re:Electricity?

[Rhinobird]

Acutally, that's stored solar power. The fern uses solar enery to grow and blah blah..

Nahhhh...

[kyletinsley]

This innovation will bring about nothing but high speed, heavily armed hover craft racing.

Oh, I don't know. The porn industry always figures out how to utilize some new invention before anybody else. I think you'll see some kind of floating blow-up dolls at PornDEX before your precious pod racers come along...

Re:Communication

[Saoshyant]

I though the speed of the propogation of gravitational force was equal to the speed of light. Is there something new that's been discovered that I'm not aware of?

An implausibility with superconductors

[texchanchan]

Obv notes accurately: "...physics is full of implausible concepts that work out..." Superconductors play close to the edge. Take this idea, for instance:

1. Make an ice chest out of single-crystal high-temperature superconductor. (Can't be done in practice yet, but nothing theoretically impossible about it.) The chest is a single crystal, the lid is another single crystal machined to very close tolerance. No gaps when you put it on.
   
2. Cool the ice chest down to liquid-nitrogen temp and run a current through it. It is now superconducting, and it is now non-conductive of heat. Put in this ice chest a solid piece of frozen oxygen or whatever you like that's cold cold cold.
3. Lid on, current now running through lid too.
   

You are now keeping a piece of oxygen frozen solid at little more than the energy expenditure to keep some nitrogen liquid. Sounds like it doesn't compute, but a cryo guy told me it would work. (Shoulda patented it...)

Has a gravitomagneticfield been proven to exist ?

[Edmund Blackadder]

Just because a theory sounds nice and fits well with other known theories (electro magnetism) does not mean it is true.

There is plenty of moving mass in the universe. Has anyone measured a gravitomagnetic effect?

i havent heard of it.

Re:Electricity?

[i_am_nitrogen]

According to a (text)book called Network Analysis I'm borrowing from my uncle, electron propagation rate is approximately 3cm/s. Although, I don't recall if that's in general, or specific to DC circuits, or an ideal rate, or just what...

Finally.... A second use

[LWolenczak]

Finally a second use for those oversized warp coils...

Re:What?

[bigsexyjoe]

No, he is hypothesizing. (I don't know if I spelled that right.) Most scientists seem to think it won't work, but he'll probably get a Nobel Prize if it does.

What evidence do we have so far?

[RyanFenton]

You'll forgive my honest ignorance - but I'm having a bit of a hard time finding more than indirect evidence pointing to the expectation that gravity should act like other recognized massless particle just because it travels like it has 0 mass - since that's just assuming it can't be different in any way in order to stick with one form of relativity.

The closest thing to direct evidence I've found for gravity travelling at light speed is in observation of the changing orbits of binary pulsars, and the like - but this is not really a satisfying set of evidence for me. It assumes so many aspects of gravitational ratiation escaping and the like, that it really doesn't seem a clear picture so much as a loose interpretation based on existing assumptions.

Also, in another part of this thread, I posted this link:

http://www.ldolphin.org/vanFlandern/gravityspeed.h tml

, which seems to be a frequently-posted link in discussions like these. I find that the path of discussion in that link has at least a few points valid enough for me to realistically doubt that gravity must act like a conventional form of radiation. I'd definetly be interested in any evidence, and I'm not at all attached to the notion that gravity acts in one way or another - so, if there's some argument or logic I'm missing, lay it on me!

:^)

Ryan Fenton

Re:What evidence do we have so far?

[rufusdufus]

gravitons are fiction until proven otherwise. I believe this is no evidence that gravity travels at any speed. Relativity predicts it, as do other theories like the one you mention, but it has never been shown experimentally.

Re:Thats one camp

[Spud the Ninja]

therefore you are a witch

Throw 'er into the pond!

Re:Electricity?

[arsaspe]

Kinda... It would be similar to the magnet + coil produces electricity concept... except the magnet has to be moving relative to the coil for it to work. Same goes for gravity + superconducter. If we got a really big superconducter and moved it back and forwards relative to the earth, then it would generate electricity, but it still wouldnt be more then the kinetic energy aplied to it in the first place. If you just thought to yourself "put it in orbit", smack yourself and write out the laws of thermodynamics 100 times. The electricity produced would come from the kinetic energy you give it, so it's just a really fancy way of converting rocket fuel to electricty.

Remember Eugene Podkletnov?

[Byteme]

...and his anti-gravity machine? This looks somewhat similar...

Dr. Podkletnov was discounted as a hoax by many sources (cited that rising gases from the coolant, air flow from spinning or magnetism influenced his results), his university ejected him and now he has retreated to a hermetic existence.

Here is a story on Wired for your reading pleasure.

Much more to look if you search Google.

Re:Remember Eugene Podkletnov?

[julesh]

his university ejected him and now he has retreated to a hermetic existence.

Hermetic? Don't think he'd last very long in an air-tight container.

nasa

[austad]

Isn't this the same type of thing that NASA funded some guy several million to develop? It was on slashdot last year sometime. Apparently, they want him to build a giant rotating superconductor that would sit below the shuttle launchpad. Even if it reduced the effective mass by only a fraction of a percent, it would save huge amounts of fuel.

I've reproduced the experiment

[NewtonsLaw]

I've just finished my own version of the experiment.

I took a tin pie tray and stuck it in the freezer for a couple of hours.

Then I rummaged through the attic and found that old turntable that used to scratch all my Barry Manilow LPs back in the '70s.

After running an extension lead from the socket on the kitchen bench over to the freezer, I stuck the plate on the turntable, set it to 78RPMs and let her rip.

The inital results were somewhat disappointing. Several spiders and a rodent that was either a very large mouse or a small rat ran out the back of the turntable and disappeared into a bag of frozen mince -- but the pie tray didn't lift up an inch.

Not to be discouraged, I figured that perhaps the reduced gravitational field only appeared above the pie tray -- so I grabbed the cat (which just happened to be passing by at the time) and pressed its warm little bottom onto the frozen pie tray.

I guess it was a little cold for him because he didn't half get excited -- or maybe I should have taken that spindle out of the center of the turntable first -- oh well.

Anyway, after a bit of hissing, growling and some bleeding (my blood not his), the cat eventually settled down enough for me to release him.

He sat their with a glazed look in his eyes and once again I flicked the switch to 78 RPMs.

Horray -- Success!

The cat lept several feet into the air, schrieking, hissing, wailing and spinning wildly at what I figured was probably 78RPMs.

But alas, the effect was short lived.

No sooner had this levitated feline lifted into the air than he crashed back down onto the rotating pie tray.

Ah, what the hell -- I slammed down the freezer lid and sat down in front of the TV with a beer.

I'll go back later and see whether he's settled down. Maybe tomorrow.

Anyway -- it looks as if there is some effect there but measuring it requires the use of protective garments and probably a more cooperative cat.

Now there's some guy called Schrodinger at the door asking whether the cat in my freezer is dead but telling me not to open the lid.

What the hell's going on there I wonder?

Re:I've reproduced the experiment

[Rogerborg]

When you take the cat out of the freezer, try buttering its back to get the desired antigravity effect.

Re:I've reproduced the experiment

[Bollie]

It's been done before! There's this experiment based on the principle that cat's always land on their feet and toast always lands butter-side down. Tape a piece of toast to the cooperative cat and presto! Anti-gravity!

Go to some web site if you don't believe me!

Sidebar says no anti-grav

[Wraithlyn]

If you click the sidebar link at the bottom, there is a paragraph that reads:

"Even if Chiao's contraption works, it wouldn't allow the generation of antigravity fields, as Russian materials scientist Eugene Podkletnov, then at Tampere University of Technology in Finland, controversially claimed to have observed in 1992 (see link ). Antigravity requires canceling out a powerful, static gravitoelectric field, yet superconductors have no effect on such fields."

Re:Sidebar says no anti-grav

[Spackler]

"yet superconductors have no effect on such fields."

So, they really aren't so super after all, are they.

-SuperSpackler
(Wow, I did a troll. I feel so dirty.)

Also note the references...

[rufusdufus]

In the abstract, he references no less than six effects with other physists last names. So name dropping probably works better than saying things like "Einstein and his cronies are fools! I am the one true world genius!"

It's not anti-grav.

[Wraithlyn]

If you check the sidebar, it mentions Dr. Podkletnov. This is different.

Re:Thats one camp

[rainwalker]

Who are you sir, who are so wise in the ways of science?

Re:Has a gravitomagneticfield been proven to exist

[XNormal]

There is plenty of moving mass in the universe. Has anyone measured a gravitomagnetic effect?

The problem is that there is either big mass moving slowly or small mass moving fast. You need a big mass to move fast to get a measurable effect. A supernova in our galaxy should generate a gravitomagnetic field big enough to measure with current sensors. On average, they happens once every few hundred years. We just need to wait...

IIRC, the gravitomagnetic field has been measured indirectly by observing the slowdown of a rapidly rotating binary star. The rate of deceleration not accounted for by other effects matched the predicted amount of energy it was supposed to lose by radiating gravitation waves with very good accuracy.

At least 30 names dropped in body of paper...

[rufusdufus]

It appears that science is much more human-interest oriented and (perhaps) less objective than we would like to believe. I counted no less than 30 different names mentioned explicitely (not used as units) in this paper. Thats almost two a page, and I didnt even count the formal acknowledgements!

Starring, in order of Apperance
Raymond Chiao
Meissner
Lense
Thirring
Ginzburg
Landau
Hertz
DeWitt
Lagrange
Hamilton
Papini
Josephson
Anandan
Cooper
Minkowski
Aharonov
Bohm
Sagnac
London
Newton
Cart
Avagadro
Gauss
Ohm
Maxwell
Ampere
Einsten
Faraday
Coulomb
Shroedinger
Fresnel
Fitelson

Re:At least 30 names dropped in body of paper...

[hazem]

What is that saying... copy one person and it's called plagarism.. copy 30 and it's called research.

Scientific American Settles it...

[i1984]

When I first glanced at this thread I figured this was just another crank story like the time machine or the previous anti-gravity superconductor, but then I saw it was in Scientific American I knew that if it wasn't crank science, it was at least probably being blown out of proportion, sensationalized, and/or taken out of context.

Perhaps that's a bit too harsh, but Scientific American has come down in the world quite a bit since the late eighties or early nineties. As I recall, they got a new editor many years ago and he was hell bent on dumbing the magazine down, fluffing it up with low-attention-theshold filler, and generally reducing it to a level of depth, insight, and relevance typical of USA Today or Omni Magazine. He suceeded, and many of the science professionals I knew cancelled their subscriptions shortly thereafter.

This subject strikes me as the researcher noting to himself "oh, hey...if I make some interesting assumptions, I get this cool effect popping out. And I might as well test it since it's so easy to test." Or an April Fools joke*. Which falls short of us dismissing the idea out of hand, but does suggest it doesn't deserve much media coverage -- at least until any positive results are verified. In other words, it was just sensationalist enough to get Scientific American's attention (they dig this kind of stuff), but not so far to the side of quackery that it has (yet) been featured in the Fortean Times.

* By the way, the paper missed April Fools day by four days; the date is stamped April 5, 2002. There's also a second date stamp of April 11, 2002. (A slightly earlier date stamp would have cleared things up pretty quickly!)

Re:Scientific American Settles it...

[platypus]

Perhaps that's a bit too harsh, but Scientific American has come down in the world quite a bit since the late eighties or early nineties. As I recall, they got a new editor many years ago and he was hell bent on dumbing the magazine down, fluffing it up with low-attention-theshold filler, and generally reducing it to a level of depth, insight, and relevance typical of USA Today or Omni Magazine.

You are completely correct. The first time I noticed this was when they began publishing articles about computer security from a person named Carolyn Meinel. You might know her name.

If not, go to google and search for "Carolyn Meinel" and "Scientific American".

You'll find for instance:

http://www.landfield.com/isn/mail-archive/1998/N ov / 040.html

(beware the /. introduced spaces min the URI)

Re:Scientific American Settles it...

[dylan_-]

You'll find for instance:
http://www.landfield.com/isn/mail-archi ve/1998/Nov / 040.html

Try here

I call bullshit

[denshi]

Yet the more implausible they seem, the more I suspect them of being over-convoluted theories that just _happen_ to match the results. Some things that seem implausible from a macro (visible, Newtonian) point of view are believable, but a lot of the quantum-level theories are just guesswork, as far as I'm concerned.

And yet, they're not guesswork. They are powerful predictive models that have enabled the construction of devices such as the one you are typing garbage into.

Physicists must publish _something_ to keep their jobs, and that's what I think drives too much of the recent scientific theorizing.

Every competent university physicist could easily double their salaries by going into industry. Not everyone in the world is as cynical and trite as yourself.

Yes, academic credentialism is driven by publishing. So? How does that translate into your assumption that all the 'recent theorizing' is bunk? Publishing is hard work. You don't just make up crap and watch is magically traverse the gauntlet of peer review.

For example, fusion research is all simply a massive boondoggle.

Oh, right, because there's no such thing as fusion. That's why we know it's a boondoggle. Oh wait. It seems fusion is actually a common physical process! Maybe we should look into it. If, you know, that's all right with you.

Another interpretation is that the space-time warp of gravity is a big illusion... that gravity isn't about mass but about energy (and mass and energy are related, thus the illusion). Thus the photons which have no mass _do_ have its analog... energy, and thats what gravity acts upon to bend the path.

Work up the math, develop a consistent theory with provable axioms, then we'll talk. This isn't consultancy, s390, this is science. Golf, blowjobs, and 'intuition' won't cut it. Oh, and physics on LSD went out 20 years ago.

Have you actually *read* the General Theory of Relativity? Go get Wheeler's "Gravitation". It deals with your confused theory, and much more besides, all coherently.

We need free thinkers in the physical sciences, but... the entire structure of academia is built to enforce conformity. Some few people survive it and think "outside the box" as it were (Feynmann comes to mind), but the majority are just buried in conformity.

There are things to be said in favor of conformity. Science was created in a time of mystics and frauds. Actually having to prove what you claim was a big jump, and conformity is a natural side-effect of that. On the other hand, there is too much conformity in the university environment these days, but for that the blame can be laid at the doors of the administration. Nationwide, administration staff has doubled relative to student&faculty populations. All the bone-headed management theories that the private sector spent the last decade or two working through have trickled into the Uni, and all the 'free thinkers' fear for their jobs. Tenure, the great bulwark of high-performance original thinkers, is on the way out.

The bottom line for me is that I'm not convinced that they're not just playing with irrelevant and really fantastic math that will never work right. When they go outside five dimensions (3 space, 1 time, 1 energy), I lose interest.

Work through the math, get back to us.

But my scientific intuition is not satisfied by the embarrassing worldwide failure to integrate General Relativity with the Standard Model of Quantum Theory. It's an intellectual debacle that the so-called "best minds" of science haven't been able to work this out for going on a century here.

Perhaps if your 'scientific intuition' was better grounded in, say, math and science, then you wouldn't troll with this garbage. Oh, we broke the Standard Model 3 years ago. Better update your notes.

Re:I call bullshit

[SpinyNorman]

What broke the standard model?

Re:I call bullshit

[denshi]

In 1998 guys at Super-Kamiokande in Takayama, Japan found solid evidence for neutrinos having mass, which is a bit of a problem since the Standard Model defines the neutrinos (all of them) as massless. Subsequent experiments have validated these results.

When CERN's next accelerator comes on line in, IIRC, 2006, we can break it a little more by continuing to find the Higgs boson, which is the Standard Model's carrier particle for mass, and has been embarrassingly elusive. Soon after, I'm hoping to collect on my bets that it won't be found.

The Standard Model has been amazingly useful. It is one of the great knowledge unifications of our time. But many working physicists will be glad to see it go, as there are too many magic numbers required, and some troublingly unexplained patterns. Physicists, too, value simplicity.

Re:I call bullshit

[davebo]

Publishing is hard work. You don't just make up crap and watch is magically traverse the gauntlet of peer review.

Oh, really?.

:)

Wot, no Cooper pairs?

[Richard Kirk]

The Ginzberg-Landau original paper just assumed the electrons paired up, and then went on to show that this had some of the right features of superconductivity. It's a tempting idea - add two fermions spin and make a boson, then let them condense. Unfortunately, it's also cheating. The microscopic explanation of why electrons should seem to pair up came a few years later with the Bardeen Cooper Schreiffer paper, and the many papers that followed.

Imagine a discreet electron moving through a positive lattice. The positive lattice will be attracted towards the negative electron. If the electron was still, the lattice would move towards it locally, and screen its charge. Because the electron is moving, and the lattice has intertia, the positive induced charge will lag behind the electron. This will slow down the electron, and also might attract any following electron if it is traveling at roughly the same speed. This is often described as electron-phononon coupling, and is rather more complicated than that simple explanation would suggest, but there is a weak force that does tend to cause electrons to match their velocities provided they maintain a respectful distance.

If electron-phonon coupling was all there was, then metals would only superconduct at a few milliKelvin. However the electrons are moving so slowly, and their wavelengths are so long, that each electron wavefunction may overlap with many thousands of others. If some of the electrons go into some ordered state, then it becomes energetically more likely for the neighbours to fit in too, and all of a sudden you get an energy gap between the ordered (superelectron) state and the disordered eletron states. This energy gap is much larger than the individual pairing energies.

If you are going to get the same sort of coupling and condensation using gravitiational waves, then you are going to need to balance the gravitational force with some sort of other repulsive force with the right sort of range. You might find this sort of balance in a neutron star, but I don't see it happening in the lab. But maybe I'm missing something...

Re:if im reading this right...

[Chris Burke]

No.

The thing that attracts us to the ground is a static field; this is only an effect of dynamic fields. Just like AC + DC. What you feel now is a more or less static field. A dynamic gravitational field at, well, any noticeable frequency would feel, I imagine, incredibly weird, like an fast rollercoaster.

IANAG I am not Alec Guiness

[Kibo]

Yes, academic credentialism is driven by publishing. So? How does that translate into your assumption that all the 'recent theorizing' is bunk? Publishing is hard work. You don't just make up crap and watch is magically traverse the gauntlet of peer review.

Well, from a certain point of view though....

At some level some publishing is, "I've noticed this quirk. It that light at the end of the tunnel illumination, or sunlight shining in my sphincter?" Sometimes in Physical Review Letters I would come across what would appear to be fairly formal flames. And other times the multitude of arguments leading to contradictory conclusions would individually be so compelling I wouldn't know what to think.

At some level all theorizing starts out as bunk, and the successful ideas percolate to the top. But I'm hardly an expert. :)

Finally!

[fleeb_fantastique]

A clear, cogent explanation for how Magneto has been able to float around for all those comics.

Now if they could only explain how The Flash manages to run so quickly without eating the entire national surplus...

Re:Thats one camp

[The Cat]

This new learning amazes me... explain again how sheep's bladders may be employed to prevent earthquakes...

rofl

Re:if im reading this right...

[Beliskner]

The thing that attracts us to the ground is a static field; this is only an effect of dynamic fields. Just like AC + DC. What you feel now is a more or less static field. A dynamic gravitational field at, well, any noticeable frequency would feel, I imagine, incredibly weird, like an fast rollercoaster

Hmmmm, in that case if you can rapidly switch the superconductor between superconducting and non-superconducting states, it might allow motion in the static field. Unfortunately since superconductors require extremely low temperatures, you'd need to rapidly rotate the temperature of the superconducting material somehow.

If the superconductor also resists changes in the direction of the gravitational field, a rotating superconductor will be affected by a static field somehow.

Why a superconductor?

[Christopher Thomas]

Superconductors seem to be the material of choice for antigravity claims nowadays. But if these effects are real, why don't we see them with normal conductors?

Even at relatively low frequencies, the reactance of, say, copper or aluminum by far dominates its resistance. This is how things like transformers and motors work. Most of the effects claimed do not seem to require perfectly resistance-free current flow, so why, in a century or more of electrical experimentation, weren't they found long ago, and why are none of these experimenters claiming results with ordinary conducting materials?

Re:Why a superconductor?

[Christopher Thomas]

The resulting expulsion of magnetic fields is called the Meissner effect. Another consequence of this is that currents can not flow in the bulk of a superconductor, but only at the surface. This is why superconducting wires are always finely threaded, to increase the surface area per weight. All of this is quite different from a normal conductor, even in the limit of zero resistance. It is all a direct consequence of the existence of a macroscopic, coherent quantum state.

My point is that you *do* see effects like this in conventional conductors as resistance approaches zero (i.e. in practice when you're at high enough frequency for reactive effects to dominate resistance). An ordinary conductor will very happily reflect/exclude applied oscillating magnetic fields by setting up opposed currents, and for the same reason you get "skin effect" for high frequency currents.

The underlying mechanisms in a superconductor are different, which causes interesting effects in the transition region (magnetic flux bundles penetrating the superconductor in regions of local breakdown, which AFAIK does not happen with conventional conductors). However, I do not recall any mention of the proposed measured effects being tied to phenomena that were exclusive to superconductors.

Hence, my question. If gravitation couples to EM, you sure as heck *should* see some interaction between gravity waves and ordinary conductors, especially since gravity waves would be coupled with an oscillating EM field.

Far Side

[N8F8]

I'll not pretend to grok the paper entirely, but a casual read remids me of a classic Far Side cartoon where a bunch of scientists are standing around a chalkboard. On the board is one of the scientist's Grand Unifid Theory. Smack dab in the middle of the equation is the phrase "And then a miracle happens".

This paper reads the same way... "When A is time-independent, this equation has the same form as the time independent Schrodinger equation for a particle (i.e., a Cooper pair) with mass m2eff and a charge e2 with an energy eigenvalue except that there is an extra nonlinear term whose coefcient is given by the coefcient x, which arises at a microscopic level from the Coulomb interactions between Cooper pairs [16]. The values of these two phenomenological parameters must be determined by experiment."

But then again, what do I know?

Not antigravity, but perhaps artificial gravity

[FreeUser]

If this works you won't be able to create antigravity fields.

Correct. But it may still have some potentially very useful applications. Artificial gravity, for one, which could make the health risks due to microgravity of a long trip to Mars, or an extended stay in orbit, a thing of the past. No need for big spinning metal canisters (which have their own navigational and structural challenges) ... just keep your superconductor in the shade and gravity will simply point 'down.' It could also be used for propulsion in space ... generate a gravitational field and let your ship 'fall' into it. Repeat as necessary until desired vector is achieved, then reverse when needed.

No, it won't get you off the surface of the earth, but once in space it could be very useful.

Re:Not antigravity, but perhaps artificial gravity

[Kintanon]

This experiment does not provide a way to manipulate anything. He is MEASURING a previously suspected but unverified gravitic wave of some kind. There is no manipulation of this. This may LEAD (In 100 years) to a reactionless drive, but it's not going to let you stick one of these things in your spaceship and set out for mars tommorow morning.

Kintanon

Sounds like the wrong experiment

[Royster]

What is claimed here is not a reduction in mass but an interference with gravity. The object sontinues to have the same inertial mass, but the gravity between the object and the earth is claimed to be blocked by the superconductor. Neat if it can be shown to work.

Re:8th grade chem?

[bluGill]

True, but science is generally required in middle school, while chemistry is optional in latter years. I don't know about your school, but my middle school general science did cover 2H+O = H20 (they didn't go into that it is actually 2H2 + O2 = 2H2O)

Middle school science was actually enough for someone who has no intention of scientific, engineering or medical work in latter years. A musician has no need to know more science, though there is nothing wrong with wanting to know more, likewise for carpenters, mechanics, fast food worker, and many other stuch jobs.

Buttered Cat Antigrav Engine is a Scam

[ShavenYak]

While the interactions between the buttered toast and the cat seem feasible to yield a perpetual motion antigravity machine, in practice the effect is useless. It can be shown mathematically that the force required to attach a piece of buttered toast to the back of a cat can only be acheived by tossing cat and toast into a black hole.

My own experimentation supports the hypothesis that building a Buttered Cat Antigrav Engine is impossible. I plan to publish the results as soon as the lacerations have healed.

Well..

[mindstrm]

I am not a physicist.. but I am reasonably certain that, on our way to a grand unified theory.. we have unified the Electric & Weak forces, yielding what we now call the Electroweak force...

(And by 'unified' I mean we have proven them to be the same thing. The universe unified them already, we just found it)

But as far as I know, and granted, I don't know everything.. we sure haven't unified Gravity & Magnetism. Yes, we see many similarities.... but we haven't unified them. I'm not saying we won't; in fact, I believe we will, it seems logical.

But the article seems to talk about this "Gravitomagnetic" force as if it is something commonly accepted by science as real.

Re:Electricity?

[mindstrm]

Right you are.
This isn't DC or AC though. And it's not a wire, it's a superconductor. Totally different.

No.

[mindstrm]

Not quite.

The idea is to get energy from the spinning of the earth, not the orbital path. You are decidedly NOT simply getting back the energy you used to put it up there; you are sapping energy from the earth spinning.

Re:No.

[arsaspe]

The energy received from doing that would be insignificant.

Help me to understand

[gsfprez]

the experiments where they have a big-ass super conductor donut - then put the frog and feather and other things in the center of the "field" (please, i don't know anything about any of this, which is why i'm asking) just float, as if gravity was cancelled out...

is this at all related to this article?

And if not - what the hell does a superconductor have to do with levitating a frog? Does the frog have metal in him? Or is what i'm refering to the Dr. Podkletnov effect?

thanks.

SR/GR had supporting evidence beforehand.

[Christopher Thomas]

This is the way it's done! Black Holes were nothing more than a theory with mathematical arguments that "seem(ed) to be correct", until CHANDRA started supplying experimental evidence. General Relativity was a theory with mathermatical aruments that "seem(ed) to be correct", until we managed to observe light bending around the mass of the sun.

Not completely true. While many additional predictions of both SR and GR were tested after the theories were proposed, part of the argument for them was that they also explained a lot of existing observations known to disagree with Newtonian mechanics.

Precession of the orbit of Mercury was one of these. Lack of the Ether Wind was another (C appeared constant independent of motion).

A model which explains previously-confusing existing results in addition to making predictions is a lot more promising than one which just proposes new results outside the domain we've already looked at (though both are of course potentially useful).

Extraordinary vs. Ordinary

[Nindalf]

An ordinary claim: My car stopped running because it ran out of gas.

An extraordinary claim: My car stopped running because last night it flew out the asteroid belt and ate three aliens, which gave it indigestion.

Why can't *all* claims be held to an equally high standard?

You go ahead and spend your life either believing that cars fly into space and eat aliens or requiring piles of solid corroborating evidence every time someone claims that cars won't run on an empty tank. The rest of us will continue to consider consistency with previous findings when evaluating new claims.

Not Anti-gravity. Cavorite!

[Remus Shepherd]

He's not going to make antigravity with this theory, no. But he might make Cavorite.

Cavorite is a fictional material that blocks gravity, and it has appeared in science fiction for decades. No, it's not as useful as antigravity...but imagine what you could do with a launch vehicle that was weightless sitting on the ground.

Cavorite is also what Podkletnov was claiming, so the crackpot alarms should be ringing about now. But if it works, this is bigger than the invention of the automobile or airplane.

Experimental flaw

[chainsaw1]

Gravity is an effect of mass, but a lack of gravity does _not_ equal a lack of mass. It equals a lack of downward force. Therefore, as long as the spinning disk was tethered to something, he wouldn't have found anything even if he had decreased gravity.

Re:One simple rule for spotting pseudo-science

[MattEvans]

There are so many grossly misinformed posts on this article, that it's hard to choose which one to respond to. I'll take a crack at this one.

"gravito-xxxxxx" forces are a quite common (among astrophysicists) way of referring to some very real consequences of the Einstein equation. The Einstein equation is the complicated, non-linear equation which describes how mass/energy and pressures couple to the curvature of spacetime. At its face, it is hardly similar to the Maxwell equations which describe electric and magnetic fields.

One way to make the Einstein equation tractable is to linearize it. I.e. start with a flat (Euclidean) spacetime, and only consider 1st-order perturbations on that. This results in a linear theory which is quite capable of describing gravitational waves, Mercury's precession, and many other "common" consequences of General Relativity (not black holes, worm holes, or any other region of strong gravity).

These linearized equations, like the Maxwell equations, do leave gauge freedom. For a particular choice of gauge, you can cast the linearized Einstein equations in a form which bears a striking resemblance to the Maxwell equations. There are some key differences, perhaps the most critical of which is the lack of a displacement current in the gravitational Ampere's Law. This is what prevents screening of the gravitoelectric field (at least to linear order).

In any event, this similarity between the Maxwell equations and the linearized Einstein equations is what gives rise to the gravitoelectric and gravitomagnetic fields (analogues to the electric and magnetic fields, of course). So don't think "bunk" when you encounter these terms. They're quite real, and are commonly found in the General Relativity literature.

Predictable outcome

[Hoi Polloi]

"Nobel prize material if it works. Footnote in Physical Review Letters if it doesn't."

I expect abuse on Slashdot regardless of the outcome. ;)

Re:Has a gravitomagneticfield been proven to exist

[peter]

There is solid evidence for gravity waves. Google for "binary pulsar gravity" if you want to find more about this piece of evidence.

Spare transducers?

[marcus]

>I don't have any spare transducers just lying around
>my garage... do you??

I'll bet you do. Have any old stereo speakers? How about a microphone? Hmm, a thermometer? All of these devices convert one form of energy to another. Do you have a boat with a depth finder? If so you have a transducer that converts electricity to sound and also does the reverse. If you look in the parts list or catalog, you will even find it listed as such: "Optional high performance transom mounted transducer $39.95"

Cheers.

Re:Electricity?

[Dyolf Knip]

And how is that solar power generated? By gravitational compression in the Sun which heats up the core to the point where fusion can take place.

Re:neutrino mass and "Standard Model"

[jaoswald]

I think you've over-emphasized the effect that neutrinos having non-zero mass has on the Standard Model.

As defined in a review paper, neutrino masses are zero only in the "minimal" Standard Model. There is probably still interesting physics in understanding the masses of the various particles, but it seems to me that most physicists don't think that we need to throw away the Standard Model to incorporate neutrino mass so much as "upgrade" it to a slightly more ornate version.

From my point of view as a physicist outside the high-energy field, the reason people say they would be "glad to see the Standard Model go" seems to be that the field of QFT has been pretty boring for a long while now, and they hope that concrete experimental results will start clearing out the dead wood from the forest of possible alternatives that have grown up in the last 30 years. On the other hand, none of those existing alternatives would excite me enough to start caring about high-energy physics again. That says to me that the theorists in QFT have pretty much exhausted their imagination without any earth-shaking possibilities.

I have a nagging feeling that we are going to have about 20 or 30 more years of high-energy physicists hoping for new physics, without getting it. Maybe the string theorists will finally connect to experimental reality, and things might get interesting again. I have a similar nagging feeling that string theorists will keep talking about the thermodynamics of black holes without having much impact on the realm of experimental physics.

Re:"Chances"?

[jaoswald]

As is obvious from the quote you use, he was calculating a probability of the OBSERVATION. It is possible for an effect to exist without being large enough to be observed. It is also possible for some defect in the experiment to cause an observed effect where no new physics is involved, or obscure the effects due to new physics.

What he is probably estimating is the chance that the current theory has existed for the length of time that it has without a valid consequence of this type not to have been discovered already. That is a statement about the somewhat random thinking of physicists, not truly about the laws of nature.

Re:Electricity?

[big_hairy_mama]

And it's not a wire, it's a superconductor. Totally different.

Right, I was responding to the guy who suggested that a *wire* could be used to the same effect as a superconducter, because of the supposed motion of the electrons in the wire.

Re:Not antigravity,

[Chris Y Taylor]

"Okay, IF this works then we're looking at a reactionless space drive. No more need to haul huge canisters of highly explosive chemicals around (once you're in orbit). Just throw together a gravity drive and a sufficiently powerful generator (yeah... 'just'), and away you go. It'd make the ion drive in DS-1 obsolete in a Big Hurry."

Yes, and No. Yes, it MIGHT make a very nice propulsion system depending on system characteristics that obviously have not been determined yet. No, it almost certainly would NOT be reactionless. And it is not just a "sufficiently powerful" generator that is needed; you also need it to be efficient, and probably accurate. It may make the ion drive obsolete, but I don't think it will do so in a "Big Hurry" as the power, efficiency, and pointing problems are going to take time to solve.

If anyone is interested in this, and will be in Indianapolis for the AIAA/ASME/SAE/ASEE Joint Propulsion Conference this July, I'll be giving a talk on this very topic at 10:30am in session#86. Or, you can just buy a copy of the paper.

My cat can eat a whole watermelon!

[John Harrison]

Well, at least it could before it died. It was also quite expert on the waterskis.

Re:"Chances"?

[jaoswald]

I agree that he believes the effect is unlikely to exist, and I still believe he is estimating an essentially probabilistic effect.

Imagine looking through a haystack for a needle. Look for a minute, there is some relatively large probability a real needle will not be found. Look for ten years, and the probability that a real needle would not have been found is extremely low. The probabilistic aspect comes about because people searching through a haystack for a needle is a process that involves a large possibility for human error.

Probabilistic expressions are used to emphasize our imperfect knowledge of the world. We can *never* know for certain what the laws of the universe are. Therefore, we express our uncertainty in terms of probability, where the sample space is "possible sets of physical laws."

Re:Electricity?

[i_am_nitrogen]

No, I believe that's vice versa, electron orbit is said to be speed of light, wave propagation is 2/3 speed of light, and actual matter propagation is centimeters per second.