Einstein's theory of relativity holds true even 13 billion light years away

Scientists have made a 3D map of 3,000 galaxies 13 billion light years from Earth, and found that Einstein's general theory of relativity is valid even far into the universe.

Since it was discovered in the late 1990s that the universe is expanding at an accelerated rate, scientists have been trying to explain why. The mysterious dark energy could be driving acceleration, or Einstein's theory of general relativity, which says gravity warps space and time, could be breaking down.

To test Einstein's theory, researchers including those from the Kavli Institute for the Physics and Mathematics (Kavli IPMU) and University of Tokyo in Japan, used data on more than 3,000 distant galaxies to analyse their velocities and clustering. Their results indicate that even far into the universe, general relativity is valid, giving further support that the expansion of the universe could be explained by a cosmological constant, as proposed by Einstein in his theory of general relativity.

"We tested the theory of general relativity further than anyone else ever has. It's a privilege to be able to publish our results 100 years after Einstein proposed his theory," said Teppei Okumura, Project Researcher at Kavli IPMU. "Having started this project 12 years ago it gives me great pleasure to finally see this result come out," said Karl Glazebrook, Professor at Swinburne University of Technology.

No one has been able to analyse galaxies more than 10 billion light years away, but the team managed to break this barrier thanks to the FMOS (Fibre Multi-Object Spectrograph) on the Subaru Telescope, which can analyse galaxies 12.4 to 14.7 billion light years away.