The Universe is so big that it can be difficult to accurately measure the huge distances between things in it. But, no longer, because now a team of researchers working on the Baryon Oscillation Spectroscopic Survey can measure distances between galaxies with 1 per cent accuracy.
The new gold standard of measurement is a big jump from previous best measurements, as Professor David Schlegel, the principal investigator of BOSS, explains to the BBC:
“There are not many things in our daily lives that we know to 1% accuracy. I now know the size of the universe better than I know the size of my house. 20 years ago astronomers were arguing about estimates that differed by up to 50%. Five years ago, we’d refined that uncertainty to 5%; a year ago it was 2%. One per cent accuracy will be the standard for a long time to come.”
How did they do it? Well, they used things called baryon acoustic oscillations — frozen imprints of pressure waves that moved through the early universe — as a kind of galactic ruler. Those oscillations happen to be exactly half a light year long, and it turns out they can be used to measure distances precisely, even from very, very long way away.
They also, neatly, provide an insight into the curvature of the Universe. “The answer is, it’s not curved much. The universe is extraordinarily flat,” Prof Schlegel told the BBC. “And this has implications for whether the universe is infinite. While we can’t say with certainty, it’s likely the universe extends forever in space and will go on forever in time. Our results are consistent with an infinite universe.”
The team presented their work at the 223rd American Astronomical Society conference in Washington DC, but a 90 per cent complete analysis of their current data is available on the Arxiv preprint server. Fortunately, it’s not quite as long a read as the galactic ruler. [arXiv via BBC]
Picture: NASA