2014-01-08. Universe Measured to One-Percent Accuracy: Most Precise Calibration Yet of Cosmic 'Standard Ruler'.

posted Jan 21, 2014, 4:25 PM by Angela Miller   [ updated Jan 24, 2014, 1:20 PM ]
For GSS A Changing Cosmos chapter 4. Excerpt: Today the Baryon Oscillation Spectroscopic Survey (BOSS) Collaboration announced that BOSS has measured the scale of the universe to an accuracy of one percent. This and future measures at this precision are the key to determining the nature of dark energy. 
...Baryon acoustic oscillations (BAO) are the regular clustering of galaxies, whose scale provides a “standard ruler” to measure the evolution of the universe’s structure. Accurate measurement dramatically sharpens our knowledge of fundamental cosmological properties, including how dark energy accelerates the expansion of the universe.
Combined with recent measures of the cosmic microwave background radiation (CMB) and supernova measures of accelerating expansion, the BOSS results suggest that dark energy is a cosmological constant whose strength does not vary in space or time. Although unlikely to be a flaw in Einstein’s General Theory of Relativity, the authors of the BOSS analysis note that “understanding the physical cause of the accelerated expansion remains one of the most interesting problems in modern physics.”
Among other cosmic parameters, says White, the BOSS analysis “also provides one of the best-ever determinations of the curvature of space. The answer is, it’s not curved much.”
Calling a three-dimensional universe “flat” means its shape is well described by the Euclidean geometry familiar from high school: straight lines are parallel and triangles add up to 180 degrees. Extraordinary flatness means the universe experienced relatively prolonged inflation, up to a decillionth of a second or more, immediately after the big bang.
“One of the reasons we care is that a flat universe has implications for whether the universe is infinite,” says Schlegel. “That means – while we can’t say with certainty that it will never come to an end – it’s likely the universe extends forever in space and will go on forever in time. Our results are consistent with an infinite universe.” ... http://newscenter.lbl.gov/news-releases/2014/01/08/boss-one-percent/ DOE/LBNL
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