Gravitational Equivalent of Magnetic Field Measured in Lab

[wolram]

http://www.physorg.com/news12054.html

Scientists funded by the European Space Agency have measured the gravitational equivalent of a magnetic field for the first time in a laboratory. Under certain special conditions the effect is much larger than expected from general relativity and could help physicists to make a significant step towards the long-sought-after quantum theory of gravity.

 

[LnGrrrR]

Hmmm interesting stuff. Especially the degree of difference between predictions and actual measurements. I can only hope that someone follows the requests of the scientists running the experiments and do some of their own to confirm/verify the findings.

 

[pervect]

*IF* this experiment is confirmed, it will be revolutionary.

However, I don't think it will be confirmed - there's no reason to expect a spinning superconductor to have a gravitomagnetic field. It reminds me a lot of the Podkletnov fiasco.

 

[wolram]

I doubt if any Earth bound experiments will ever solve the mystery of gravity
but what are these people messuring ?

 

[duke_nemmerle]

UHHHHHHHHHH? Isn't this gravitomagnetic field the one that was predicted by the "crackpot" Heim in his crazy theory that derives masses from first principles? I'm going to have to take another look at it

 

[pervect]

I doubt if any Earth bound experiments will ever solve the mystery of gravity
but what are these people messuring ?

Small acceleration sensors placed at different locations close to the spinning superconductor, which has to be accelerated for the effect to be noticeable, recorded an acceleration field outside the superconductor that appears to be produced by gravitomagnetism. "This experiment is the gravitational analogue of Faraday's electromagnetic induction experiment in 1831.

So they mount an acceleration sensor (probably a gravimeter) above a spinning superconductor disk, and they think that they are getting some DC signal out of the sensor when the disk spins, due to the gravitational field of the disk itself which is obviously very small. This signal is so small that they really only measure the AC signal produced when the disk accelerates.

It will probably turn out to have some mundane explanation, for instance the signal that is powering their motor could be being picked up by their wiring (by induction if it's AC, by a ground loop if it's DC), so that there is an AC signal from the accelration sensors when the motor is running, but it's not due to gravitational effects, but stray coupling.

 

[clj4]

It will probably turn out to have some mundane explanation, for instance the signal that is powering their motor could be being picked up by their wiring (by induction if it's AC, by a ground loop if it's DC)

That would be very disappointing, I would hope that they figured out the shielding and that they have separated the power planes. This would be very sad, 3 years down the drain because of some elementary error.

 

[PhilosophyofPhysics]

lol, I was so excited to see language similar to what I used last week in this article. I was playing around over spring break and came up with these becuase I was wondering if there was an analogue to magnetism for gravity.

$$\vec{F} = frequency field$$

$$m_c = mass current$$

$$F_f = Frequency force$$

$$\vec{\ F _f} = m_c \vec{\ L} \times \vec{F}$$


$$\Phi_F = \oint \vec{\ F} \cdot \vec{dA}$$

$$\oint \vec{\ F} \cdot \vec{ds} = \nu_0 m_c_e_n_c$$

$$\oint \vec{\ G} \cdot \vec{dl} = - \frac{d \Phi _F}{dt}$$

$$d\vec{\ F} = \frac{\nu _0}{4\pi} \frac{m_c \vec{\ ds} \times \vec{r}}{r^3}$$

 

[Garth]

I was playing around over spring break and came up with these becuase I was wondering if there was an analogue to magnetism for gravity.

There is - it is called the gravitomagnetic or Lense-Thirring or frame-dragging effect and is being properly tested at this moment as the GP-B data is being analysed.

Garth

 

[wisp]

This could be the break through that follows on from Podkletnov's work.

The way in which Podkletnov's work was reported was strange, but I believe it to be genuine.

 

[ZapperZ]

I guess people still hasn't learned not to do physics via press conferences. What, no one paid any attention to one of the questions posted in the comments asking for peer-reviewed journals where this is published? It seems that they missed "announcing" where they have submitted such a thing.

Zz.

 

[Creator]

I agree: shame on physorg.com for not even providing the reference to where the work is published.

It can be found on lanl archives here:
http://lanl.arxiv.org/abs/gr-qc/0603033

Apparently it was also submitted for pier review to Physica C.

Creator

 

[clj4]

I agree: shame on physorg.com for not even providing the reference to where the work is published.

It can be found on lanl archives here:
http://lanl.arxiv.org/abs/gr-gc/0603033

Apparently it was also submitted for pier review to Physica C.

Creator

For some reason your link didn't work.
This one works for me:

http://esamultimedia.esa.int/docs/gsp/Experimental_Detection.pdf

Should be interesting to see how and if the results correlate with GP-B.

 

[clj4]

This could be the break through that follows on from Podkletnov's work.

The way in which Podkletnov's work was reported was strange, but I believe it to be genuine.

nope, it was never replicated.

 

[Creator]

Try it now clj4. I've corrected it.
It's a Los Alamos preprint : http://lanl.arxiv.org/abs/gr-qc/0603033

It's the same report... physorg.com should have at least included it.

Creator

-- I suport publik edjucashon--

 

[clj4]

Try it now clj4. I've corrected it.
It's a Los Alamos preprint : http://lanl.arxiv.org/abs/gr-qc/0603033

Creator

-- I suport publik edjucashon--

Yes, thank you, now we have two links to work with!

 

[ZapperZ]

I agree: shame on physorg.com for not even providing the reference to where the work is published.

It can be found on lanl archives here:
http://lanl.arxiv.org/abs/gr-qc/0603033

Apparently it was also submitted for pier review to Physica C.

Creator

Now that's strange. Why would something that they claim to be THAT revolutionary and important, is submitted to Physica C? This is not a knock on Physica C (I have published a paper there), but shouldn't something this important be sent to Nature or Science, or PRL even?

And let's not forget, Podkletnov's first paper on the dubious gravitational shielding was published in Physica B.

Zz.

 

[Creator]

Now that's strange. Why would something that they claim to be THAT revolutionary and important, is submitted to Physica C? This is not a knock on Physica C (I have published a paper there), but shouldn't something this important be sent to Nature or Science, or PRL even?

Most of de Matos' previous theoretics answering the Tate cooper pair mass anomaly (1989) has been published in Physica C,
which is (as you know) appropriate for superconductors. I think his experimental follow up should therefore be given review there.

As far as Nature or Science ...they probably wouldn't have touched it until it had been pier reviewed.

I am, however, glad this topic has come up here in PF since it contains some physics not generally well known and which isn't usually even addressed in graduate physics.

I believe I may have addressed some of these concepts and background once here on PF, but only briefly, possibly in relation to the GPB's niobium spheres which rely on the London moment for its axial readout.
Maybe I'll put more details of this mass anomaly issue when I have some free time.

Creator

 

[ZapperZ]

Most of de Matos' previous theoretics answering the Tate cooper pair mass anomaly (1989) has been published in Physica C,
which is (as you know) appropriate for superconductors. I think his experimental follow up should therefore be given review there.

But PRL, Science, and Nature are also appropriate for superconductors also. I know, I've published in those. And this report transcends just superconductors since it claims to have affected gravitational field. Physica C isn't in the same caliber as those journals. It isn't even in the same caliber as PRA, PRB, etc. Just look at the citation index for that journal if you don't believe me.

As far as Nature or Science ...they probably wouldn't have touched it until it had been pier reviewed.

Er... come again?

If this has been "peer-reviewed", you won't get it published in Nature and Science. They want something new and high-impact.

I am, however, glad this topic has come up here in PF since it contains some physics not generally well known and which isn't usually even addressed in graduate physics.

Maybe because this is still (i) a research front area (ii) unproven (iii) unverified (iv) not widely accepted (v) is one of a number of theoretical hypothesis.

Zz.

 

[pervect]

I am, however, glad this topic has come up here in PF since it contains some physics not generally well known and which isn't usually even addressed in graduate physics.

I believe I may have addressed some of these concepts and background once here on PF, but only briefly, possibly in relation to the GPB's niobium spheres which rely on the London moment for its axial readout.
Maybe I'll put more details of this mass anomaly issue when I have some free time.

Creator

I may be digging up an old thread here, but one reason I don't believe this result is that I was under the impression that a even a field-theoretic approach to gravity using spin-2 gravitons was bound to wind up with GR.

See for instance

http://xxx.lanl.gov/abs/astro-ph/0006423

A pedagogical description of a simple ungeometrical approach to General Relativity is given, which follows the pattern of well understood field theories, such as electrodynamics. This leads quickly to most of the important weak field predictions, as well as to the radiation damping of binary pulsars. Moreover, certain consistency arguments imply that the theory has to be generally invariant, and therefore one is bound to end up with Einstein's field equations. Although this field theoretic approach, which has been advocated repeatedly by a number of authors, starts with a spin-2 theory on Minkowski spacetime, it turns out in the end that the flat metric is actually unobservable, and that the physical metric is curved and dynamical.

Short sections are devoted to tensor-scalar generalizations, the mystery of the vacuum energy density, and quintessence.

Thus I would not expect results that were 10^20 different from GR's results, most especially in weak-field results, from any quantum theory of gravity.

However, I am not very familiar with the details of these field-theoretic arguments, just that they exist.

 

[clj4]

Try it now clj4. I've corrected it.
It's a Los Alamos preprint : http://lanl.arxiv.org/abs/gr-qc/0603033

It's the same report... physorg.com should have at least included it.

Creator

-- I suport publik edjucashon--

Yep, thank you, it works fine!