Dark Order of the Universe:Distant galaxies align to support Einstein’s general theory of relativity 

The 3D position and shape information of each galaxy helped measure the extent of the array relative to distant galaxies.

Scientists have confirmed that the galaxy’s unique array can probe dark matter and dark energy on a cosmic scale, supporting general relativity on vast spatial scales. However, the nature of dark energy and cosmic acceleration remains unclear. 

Einstein would nod in agreement. General relativity holds true even in the most remote corners of the universe.

Scientists from international research institutes, including Kyoto University, now confirm that the unique arrangement of galaxies exhibits properties that make them powerful probes of dark matter and dark energy on a cosmic scale.

By collecting evidence that the distribution of galaxies more than 10 million light-years away is affected by the gravitational pull of dark matter, the researchers have successfully tested the general theory of gravity on a huge spatial scale. An international team analyzed the positions and orientations of galaxies from an archive of 1.2 million galaxy observations. Using the available 3D position information for each galaxy, the resulting statistical analysis allowed us to quantitatively characterize how distant galaxies are aligned. 

“These alignments, mainly caused by interactions with nearby objects, were regarded as systematic noise when measuring weak lensing effects,” said lead author Yukawa Institute for Theoretical Physics, Kyoto University. Atsushi Tarutani explains.

Teppei Okumura of the Institute of Astronomy and Astrophysics, Academia Sinica, said, “We also succeeded in measuring the speed at which the distribution of galaxies gradually thickens due to gravity. This is consistent with general relativity.”

“Our study confirmed general relativity in the distant universe, but the nature of dark energy and the origin of cosmic acceleration remain unclear,” added Okumura. 

The archived data – obtained from the Sloan Digital Sky Survey and the Baryon Oscillation Spectroscopic Survey – consists of three samples of galaxies, selected for brightness and distance. In addition, each galaxy’s 3D position and shape information helped assess the extent of alignment with distant galaxies.

The team’s modeling results confirmed the theoretical calculations and provided Taruya and Okumura with strong evidence that the orientations of these galaxies are related, further supporting general relativity at the cosmological level.

“Current endeavors, such as the Subaru Telescope project, will provide extremely high-quality, high-precision observational data. These will spearhead innovative cosmological research using the intrinsic alignments to shed light on the nature of dark energy,” notes Taruya.