Evidence found for gravity waves

http://www.bbc.co.uk/news/science-environment-19408363

quote:

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Researchers have spotted visible-light evidence for one of astronomy's most elusive targets - gravity waves - in the orbit of a pair of dead stars.

Until now, these ripples in space-time, first predicted by Einstein, have only been inferred from radio-wave sources.

But a change in the orbits of two white dwarf stars orbiting one another 3,000 light-years away is further proof of the waves that can literally be seen.

A study to be reported in Astrophysical Journal Letters describes the pair.

Gravitational waves were a significant part of Albert Einstein's general theory of relativity, which viewed space itself as a malleable construct, and the gravity of massive objects as a force that could effectively warp it.

Catching sight of an actual gravity wave, however, is a tricky business; their effects are far too small to be measured with Earth-bound experiments.

But the wider Universe provides a laboratory in which the indirect effects of gravity waves can be measured.

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more at the link!

Edited by Adminnemooseus, : Restore lost "R" at beginning and add quote box.

Was the evidence for these gravity waves found by a black hole (or other rapidly rotating heavenly body)?

Yes. White Dwarf Stars rotate relatively rapid.

Well then isn't it obvious that due to the size and density of the star, gravity waves would form.

I think it would do you well to read the article, or even better, the paper associated because:

due to the size and density of the star,

It was found near two orbiting white dwarf stars, not a single star and:

Well then isn't it obvious

The key find here as that it is visual evidence, as opposed to inference from radio waves. I am unsure what the size of the stars has to do with this find. Could you explain?

Well then isn't it obvious that due to the size and density of the star, gravity waves would form.

Just to avoid confusion, the gravity waves result from the orbit of the star about another star. Newtonian gravitational theory would predict a stable orbit, while GR predicts a decaying orbit with energy emitted from the system via gravity waves. A single isolated massive object could not be used in this experiment.

In a sense, yes it was obvious. General does predict gravity waves, and the theory is well verified. What's discussed here is confirmation that Einstein's theory is correct.

What makes the current experiment unique is that it is an experiment using visible light rather than radio waves to determine the variation in orbital periods. Also the results were gathered in a rather short period of time.

Well then isn't it obvious that due to the size and density of the star, gravity waves would form.

No - gravitational waves cannot be formed from a symmetrical object, irrespective of its density and size. A varying gravitational quadrupole is required.

This is almost the same situation as electromagnetism, where a single static charge cannot generate electromagnetic waves - a varying dipole is required. The difference between em and gravity is accounted for by the vector nature of e/m vs the symmetric tensor nature of gravity - or equivalently the fact that e/m comes with +ve and -ve charges, where-as gravitational mass is purely +ve.

Well if you look near a black hole you can see waves when light gets caught in its gravitational pull. Thats what I thought he meant when I first saw the topic.