Illustration Credit: Zosia Rostomian (LBNL), SDSS-III, BOSS
Explanation: How large do things appear when far away? When peering
across the universe, the answer can actually tell us about its average
gravitational history and hence its composition. Toward this goal, the Baryon Oscillation Spectroscopic
Survey (BOSS) of the Sloan Digital Sky
Survey-III (SDSS-III) has measured slight recurring density enhancements in
galaxy densities up to six billion light
years away (redshift 0.7), when the universe was
about half its current age. These density ripples are
known as baryon acoustic
oscillations (BAOs) and are expected to emerge from
the early universe at a known size scale. BOSS's measurements of this size scale
indicate a strong universe component of dark
energy, and so bolsters previous indications of this unusual composition. Pictured above is an
artist's illustration depicting exaggerated BAOs in the distant universe.
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