Baryon Acoustic Oscillations from SDSS III
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.
Authors & editors:
Robert Nemiroff
(MTU) &
Jerry Bonnell
(USRA)
NASA Web Site Statements, Warnings,
and Disclaimers
NASA Official: Jay Norris.
Specific
rights apply.
A service of:
LHEA at
NASA /
GSFC
& Michigan Tech. U.
