Astronomers have measured the distances between galaxies in the universe to an accuracy of just about 1%. This staggeringly precise survey - across six billion light-years - is key to mapping the cosmos and determining the nature of dark energy. The new gold standard was set by BOSS (the Baryon Oscillation Spectroscopic Survey) using the Sloan Foundation Telescope in New Mexico, US. It was announced at the 223rd American Astronomical Society in Washington DC.
"I now know the size of the universe better than the size of my house,”
"The ruler happens to be half a billion light years long, so we can use it to measure distances precisely, even from very far away." Determining distance is a fundamental challenge of astronomy: "Once you know how far away it is, learning everything else about it is suddenly much easier," said Daniel Eisenstein, director of the Sloan Digital Sky Survey III.
The BOSS distances will help calibrate fundamental cosmological properties - such as how "dark energy" accelerates the expansion of the universe. An analysis of the current data - 90% complete - is published on the Arxiv preprint server, with final results expected in June.
After that, future surveys will have to start filling in the enormous gaps between the vast boundaries the BOSS team have defined - and to go much deeper in space. This latter task will be a key objective of Europe's Euclid space telescope due to launch at the end of the decade.