January 9, 2014
Measurement Of Universe Accurate To One Percent Completed By BOSS
redOrbit Staff & Wire Reports - Your Universe Online
Researchers from the Baryon Oscillation Spectroscopic Survey (BOSS) announced on Wednesday that their project has measured the scale of the universe to an accuracy of one percent – precise measurements that will help astronomers in their search to determine the true nature of dark energy.
“One-percent accuracy in the scale of the universe is the most precise such measurement ever made,” explained principal investigator David Schlegel, a member of the Physics Division of the US Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab).
“Twenty years ago astronomers were arguing about estimates that differed by up to fifty percent,” he added. “Five years ago, we'd refined that uncertainty to five percent; a year ago it was two percent. One-percent accuracy will be the standard for a long time to come.”
BOSS, the largest program in the third Sloan Digital Sky Survey (SDSS-III) multi-filter imaging and spectroscopic redshift analysis, has been using a telescope at the Apache Point Observatory in New Mexico to record high-precision spectra of well over a million galaxies with redshifts from 0.2 to 0.7 since 2009.
The researchers believe that it has successfully looked six billion years into the universe’s past, and that its database includes more redshifts of galaxies than have been collected by the rest of the world’s telescopes. Their findings are based on SDSS-III's Data Releases 10 and 11 (DR 10 and DR 11), which have been submitted for publication in the Monthly Notices of the Royal Astronomical Society.
Their analysis reportedly incorporates spectra from more than 1.2 million galaxies and covers over 8,500 square degrees of the sky visible from the Northern Hemisphere. It is the largest sample of the universe ever surveyed at this density. Furthermore, by the time BOSS is completed, it will have collected high-quality spectra of some 1.3 million galaxies, as well as 160,000 quasars and thousands of other astronomical objects.
In addition, according to Berkeley Lab member and BOSS science survey team chairman Martin White, the analysis also provided the research team with “one of the best-ever determinations of the curvature of space. The answer is, it's not curved much.” White added that while the project will continue gathering data through June, the latest results comprise 90 percent of the final BOSS data.
"There are not many things in our daily life that we know to one-percent accuracy. I now know the size of the Universe better than I know the size of my house,” Schlegel added. The results were presented Tuesday at the 223rd meeting of the American Astronomical Society (AAS) by Harvard-Smithsonian Center for Astrophysics astronomer and SDSS-III director Daniel Eisenstein.