Ripples in the cosmic background
Tuesday, September 7, 2010 - 13:07
in Astronomy & Space
(PhysOrg.com) -- The universe was created 13.73 billion years ago in a blaze of light -- the big bang. We also think that, about 380,000 years later, after matter (mostly hydrogen atoms) had cooled enough for neutral atoms to form, light was able to travel through space relatively freely. We see that light today as the cosmic microwave background radiation (CMBR). The light appears extremely uniform in brightness across the sky. Astronomers have discovered, however, that the radiation has very faint ripples and bumps in it, at a level of only about one part in one hundred thousand.