Astronomers glimpse dawn of universe’s accelerating expansion

A major international collaboration involving Yale researchers has produced the most precise measurements yet of the distances to galaxies in the universe’s far reaches, offering a glimpse of the time when the universe began its accelerating expansion.

The work shows that the numerous galaxies are growing father apart, and ever faster, according to Nikhil Padmanabhan, assistant professor of physics. He is co-lead of one of six related papers released March 30 and published in an open electronic archive of scientific paper preprints.

“By combining previous survey results with these new results for even more distant galaxies, we have mapped out the expansion of the universe over the last six billion years, with an accuracy of better than two percent,” Padmanabhan said.

The overall collaboration, known as the Sloan Digital Sky Survey III (SDSS-III), is mapping the Milky Way, searching for extrasolar planets and investigating the nature of dark energy. The largest component of the universe, dark energy is a primary cause of the universe’s hastening expansion.

The Yale research was part of the Baryon Oscillation Spectroscopic Survey (BOSS), itself one of SDSS-III’s component surveys. The BOSS is producing the most detailed ever map of the universe to better map the expansion rate of the universe. The recently released papers collectively report on analysis of date from the first two years of observations.

Padmanabhan presented the work April 2, at the American Physical Society meeting in Atlanta.

He worked closely with two Yale postdoctoral researchers, Antonio Cuesta and John Parejko, on the latest results, which relied heavily on Yale’s high-performance computing facilities.

The broader SDSS-III collaboration involves researchers from Yale and dozens of other major research institutions around the world. It began gathering data in 2008 and will continue through 2014 using equipment at the Apache Point Observatory in New Mexico.

For more details on the SDSS-III collaboration, visit the website.