Vlad Tarko writes on Softpedia:
According to Einstein’s theory of general relativity, a moving mass should create another field, called gravitomagnetic field, besides its static gravitational field. This field has now been measured for the first time and to the scientists’ astonishment, it proved to be no less than one hundred million trillion times larger than Einstein’s General Relativity predicts.

This gravitomagnetic field is similar to the magnetic field produced by a moving electric charge (hence the name “gravitomagnetic” analogous to “electromagnetic”). For example, the electric charges moving in a coil produce a magnetic field — such a coil behaves like a magnet. Similarly, the gravitomagnetic field can be produced to be a mass moving in a circle. What the electric charge is for electromagnetism, mass is for gravitation theory (the general theory of relativity).

A spinning top weights more than the same top standing still. However, according to Einstein’s theory, the difference is negligible. It should be so small that we shouldn’t even be capable of measuring it. But now scientists from the European Space Agancy, Martin Tajmar, Clovis de Matos and their colleagues, have actually measured it. At first they couldn’t believe the result.

Didn't Einstein denounce his Theory of Relativity shortly before his death?

Mark

It doesn't matter if Einstein renounced his theory or not. If one is trying to learn something about Nature, what matters is only how productive the theory itself is (or isn't).

tonyviner

It seems like it would matter a little bit. There was surely a reason that the man who came up with said theory ultimately decided that it was wrong.

Mark

The theory either works (experimentally) or it doesn't. When it comes down to choosing between a theory which works and deferring to the opinions of the guy who just happened to have discovered it, physicists will always choose the working theory. That's the whole objective, to have ways to understand the World.

This isn't just rhetoric on my part; it's done all the time. It's even been done in the case of Einstein. He was wrong about a number of things. The most famous example is his chauvinism against the probabilistic nature of Quantum Mechanics, a theory which works at least as well as General Relativity.

Einstein the man isn't the last word on Einstein's theories. There are thousands of people alive today who understand Einstein's theories better than Einstein did. It's because time doesn't stand still. Relativistic theory isn't holy scripture. People are still making progress with it, finding its strengths and weaknesses.

nemoide

This story is about four years old. Doing a Google News search for “theory of relativity” shows a recent article claiming that the theory still stands strong. (here: http://www.sciencedaily.com/releases/2010/02/10…)

Since the Softpedia article is full of spelling and grammar errors, I'm inclined to not trust it wholesale. I can't really tell if it's SUPPOSED to be a joke or not so I thought I would at least point this out?

The reason it hasn't made a big splash is because the experimental data haven't been reproduced. It's not know if their methodology is reliable or not.

Bill

This article is both wrong and right. It is right in that the effect has been measured, and is different from what is predicted by General Relativity. It is wrong in that it makes the difference sound huge. We are talking about the difference of a prediction of 0.999992 to a measured value of 1.000084(21). It should be noted however, the prediction is done simply by considering first order effects. Further analysis has shown the difference could be resolved by including the second order effects.

Tajmar, M., and de Matos, C.J., Gravitomagnetic Field of a Rotating Superconductor and of a Rotating Superfluid. Physica C 385(4), 551-554 (2003). Tajmar, M., and de Matos, C.J., Extended Analysis of Gravitomagnetic Fields in Rotating Superconductors and Superfluids. Physica C 420(1-2), 56-60 (2005). De Matos, C.J., and Tajmar, M., Gravitomagnetic London Moment and the Graviton Mass inside a Superconductor. Physica C 432, 167-172 (2005).

Mark

Thanks. That's very informative.

Bill

The problem is people, the calculations are damn hard. An electro-magnetic field does not bend space and time. So figuring out things like an inverse square law for F vs distance is not too hard. Even then though, the calculations become tricky because even a vacuum can be polarized, reducing the effective charge. So even E-M calculations are normally approximate. For General Relativity it is far more complicated. How do you compute an inverse square law, when your mass has curved space and time and changed the distance between the two objects? It is further complicated because we don't have a quantum mechanics model for gravity. So we don't know things, like can a vacuum become polarized for mass? Some theories such as Heim theory predict a very strong polarization, while others predict virtually none. In the end all we can exactly is first, or maybe second order calculations. So it is not surprising there is a minor disagreement between measured values and predicted values. That does not mean GR is wrong. It just means there is more to the problem than just our first order GR calculations.