September 28, 2011
Einstein’s Theory Of Relativity Confirmed
New measurements have confirmed Albert Einstein's general theory of relativity after an experiment last week brought the theory into question.
Einstein's general theory of relativity says that light emitted from stars and galaxies is slightly tugged by gravity from celestial bodies.
Physicists reported last week that neutrinos can travel faster than light, which sent a blow to Einstein's theory of special relativity.
The particles in the experiments conducted between the European Center for Nuclear Research (CERN) in Switzerland and a laboratory in Italy were clocked at 186,000 miles per second, which is about 3 miles per second faster than the speed of light.
The physicists admitted they were perplexed by the findings, and other experts were also skeptical.
However, another experiment has validated Einstein's theory, despite last week's findings.
The Danish astronomers have put the theory to test in measuring light emitted by galactic "clusters."
These clusters are sectors of deep space which are packed with thousands of galaxies and are held together by their own gravity. The density and mass of these clusters should have a perceptible gravitational effect on the light they emit.
Radek Wojtak, a cosmologist from the University of Copenhagen, and colleagues analyzed light from 8,000 of these clusters.
The astronomers were looking for variations in "redshift," which is a measurement of the shift in light.
The team measured the wavelength of light from galaxies lying in the middle of the galactic clusters.
"We could measure small differences in the redshift of the galaxies and see that the light from galaxies in the middle of a cluster had to 'crawl' out through the gravitational field, while it was easier for the light from the outlying galaxies," Wojtak said in a press release.
The team then measured the galaxy cluster's total mass to get a fix on its gravitational potential.
"The redshift of light is proportionately offset in relation to the gravitational influence from the galaxy cluster's gravity," Wojtak said in a press release.
"In that way, our observations confirm the theory of relativity."
This is the first experiment that had tested Einstein's theory of the impact of gravity outside of the Solar System.
Wojtak's research was published on Wednesday in the British Scientific Journal Nature.
Image 1: Researchers have analyzed measurements of the light from galaxies in approximately 8,000 galaxy clusters. Galaxy clusters are accumulations of thousands of galaxies (every light in the image is a galaxy), which are held together by their own gravity. This gravity affects the light that is sent out into space from the galaxies. Credit: Hubble Space Telescope
Image 2: Until now, the gravitational redshift has only been tested with experiments and observations in relation to distances her on Earth and in relation to the solar system. With the new research the theory has been tested on a cosmological scale for the first time by analyzing galaxies in galaxy clusters in the distant universe. It is a grotesquely large scale, which is a factor 1,022 times greater (ten thousand billion billion times larger than the laboratory test). The observed data confirms Einstein´s general theory of relativity. Credit: Dark Cosmology Centre, Niels Bohr Institute
On the Net: