http://sanfrancisco.ibtimes.com/articles/222083/20110929/galaxy-clusters-light-confirms-einstein-general-theory-of-relativity.htmEinstein was positively right about relativity.
Albert Einstein revolutionized the way science thought about space and time when he said the two were inseparable. But one of the more unprovable ramifications was that mass has a warping effect on space-time, much like a bowling ball set on a mattress would depress the cushion around itself.
But now a group of researchers in Denmark has showed Einstein's general theory of relativity was right all along. Astrophysicist Radek Wojtak led the team in examining 8,000 galaxy clusters to put Einstein's theory to the test. Galaxy clusters are gigantic objects with thousands of galaxies, with much stronger gravity present in their centers.
According to the theory, light should lose energy when escaping from a gravitational field. And the light will lose more energy escaping from a stronger field. So light coming from the center of the galaxy clusters should lose more energy than light coming from the edges of the cluster. This is called gravitational redshift.