Early results from a Nasa mission designed to test two key predictions of Albert Einstein show the great man was right about at least one of them. It will take another eight months to determine whether he got the other correct say scientists analysing data from Nasa's Gravity Probe B satellite. Gravity Probe B uses four ultra-precise gyroscopes to measure two effects of Einstein's general relativity theory. One of these effects is called the geodetic effect, the other is called frame dragging. A common analogy is that of placing a heavy bowling ball on to a rubber sheet. For the full story: Click Here or here.

well yeah, of course Einstein was right, i cant beleive there are so many people trying to refute his findings.

I can believe you would say that but it assumes something not in evidence.

Fact: We know relativity is not complete.

Fact: We know quantum mechanics is not complete.

Fact: We know the two theories, while internally consistent are not compatible.

We don't test and retest relativity to throw it away: Newton's work was not thrown away. Rather we examine it in closer and closer detail in order to learn how we can best build upon it to make a more adequate analog of reality.

It will be a great day when the relativity-theory/quantum-theory problem is resolved. These experiments are making scientific history. Further investigation will hopefully reveal further details that may allow a realignment of those two theories such that they can logically co-exist, or 'fit together'. I would think that would bring a GUT much closer.

I just wanted to add to DA Morgan's comments.

All the tests of relativity (to my knowledge) have been in weak-fields, this is generally why the characteristic effects of GR are so hard to detect. Physicists are yet to undertake the most important tests of GR i.e. measuring the effects of gravity in a strong field case (black hole).

There have been various results in astronomy that are consistent with GR, one that immediately springs to mind is the orbital period a pulsar and neutron star - orbital period decay is consistent with gravitational wave emission; although, we haven't detected these waves yet.

The next generation of X-ray telescopes might provide even stronger proof of GR, but the most exciting prospect for GR is LISA. Imagine if LISA detected the gravitational waves of a stellar mass black hole orbiting a supermassive black hole - the stellar mass BH could be used as a test mass to MAP the metric of the supermassive black hole i.e. does the metric, at all, look like Kerr?!

Thanks,
Durante.

Durante, please would you put me out of my misery. What's 'Kerr'? Is it something to do with the Magneto-optic Kerr effect?

Thanks.

No problem redewenur.

By examining the gravitational radiation emitted by the system (stellar mass black hole orbiting a supermassive black hole) it might be possible to directly measure the geometry of the surrounding spacetime. It is thought that most (useful) black holes are best described by the Kerr metric - which describes the geometry of spacetime around a massive rotating object. A direct measurement of the spacetime around a supermassive black hole would allow comparison to the Kerr metric i.e. do we understand black holes at all theoretically?

If the spacetime is approximately described by the Kerr metric - good result the theory guys got it right (Einstein et al...)

If not, something might be wrong with the GR - perhaps more interesting...

I've been to a few seminars on LISA, and this is all infinitely harder than i make it sound. But the idea is nice.

Durante.

Thanks very much for the info Durante. The truths of the 21st century promise to be stranger than fiction.

For anyone interested, here's a colourful and informative brochure about LISA:

http://lisa.nasa.gov/LISAbrochure.pdf

Thanks for the link, rede. It explains a lot. Now I have some idea what you guys are talking about.

Amaranth

Stranger than fiction is right. That brochure reads like a script from Star Trek! What amazing stuff. Will it work? Or maybe I should be asking, is it an experiment designed solely to prove (or not) that Einstein was right and there are gravitatioal waves, or will there be a possible practical application for the result as well? It will be amazing indeed if it does all they are hoping.