Is Einstein finally wrong? Far-off galaxies are tugging each other more tightly than Einstein's gravity theory predicts, suggests an analysis of light from distant stars.
Now available in an online physics paper archive, the analysis by Cornell cosmologist Rachel Bean looks at how galaxies attract one another roughly one billion light-years away. Einstein's theory of gravity, General Relativity, suggests that gravity should attract light just as strongly as it attract other matter, but the Hubble Space Telescope’s "COSMOS survey" data suggest gravity attracts light less than it does stars in the survey data.
"These results are a preliminary step in using current cosmological data to test gravity on very large scales," says Bean. "We need to look at more slices of time, more data, to see if this is real."
"I can certainly say that 'if' the analysis and data are both on a solid footing, than this certainly is an important, and newsworthy, result," says Caltech physicist Sean Carroll, who reported the analysis on his Cosmic Variance blog. "The straightforward interpretation of the result is that something is wrong with General Relativity - space is not getting curved as much as time is." The analysis statistically finds only a 2% chance of its gravitational anomaly being wrong, but Bean cautions that, "more work needs to be done to see if this is real."
Light bending less than galaxies under gravity's pull would offer a first real hint about the mysterious "dark energy" pulling galaxies apart at an accelerating rate, say both Bean and Carroll. First observed in 1998 measures of exploding stars, dark energy continues to confuse cosmologists, who expected to find gravity only pulling galaxies towards one another, not apart at an increasing rate. "Of course, there are all kinds of crazy theories out there about Einstein wrong about this or that," Carroll says. "But we really need to test his predictions against real data, just like (Bean's analysis), to find out his theory's limits."
Source: http://blogs.usatoday.com/sciencefair/2009/10/einsteins-theory-of-general-relativity-may-have-been-flawed.html
