A new study from Great Britain indicates that Albert Einstein’s theory of general relativity, which posited that what we perceive as gravity arises from the curvature of space and time, is not only true for planet Earth, but is a constant in galaxies far, far away.
The result of this corroboration of Einstein’s theory is that the supposition of such entities as dark matter and dark energy gain genuine credence. The standard model of cosmology, which tries to understand how fundamental forces and particles in the universe work and behave together, leaves it to dark matter to explain the speed with which stars orbit galaxies and to dark energy to explain why the universe’s expansion is accelerating.
The study, conducted by an international team of astronomers led by Thomas Collett of the Institute of Cosmology and Gravitation at the University of Portsmouth in the U.K., was the first time that general relativity was tested in regions far beyond our galaxy. Collett and his team used data from NASA's Hubble Space Telescope and the European Southern Observatory's Very Large Telescope in Chile to make its assumptions.
Terry Oswalt, an astronomer and chair of physical sciences at Embry-Riddle Aeronautical University in Florida, told Space.com that verifying general relativity "at all possible scales (especially the largest scale) is fundamentally important to physics as a whole, and to cosmology in particular.”
The team of astronomers utilized strong gravitational lensing, which entailed using the galaxy ESO 325-G004, 500 million light-years from Earth and with enormous mass, to bend light so a galaxy beyond it could be viewed.
As Space.com writes, “In addition to measuring the space-time curve, the researchers had to determine the galaxy's mass, because general relativity predicts how much curvature is created by a mass. They calculated this mass by measuring how fast the galaxy's stars travel. Then, by comparing this measured mass with the measured curvature of space-time, the team found what general relativity predicts for this mass, or galaxy.”
Thus, as Collett asserts, general relativity is the correct theory of gravity even outside our solar system. Team member Bob Nichol, director of the Institute of Cosmology and Gravitation, concluded, "It is so satisfying to use the best telescopes in the world to challenge Einstein, only to find out how right he was.”