The BICEP (Background Imaging of Cosmic Extragalactic Polarization) telescope at the South Pole, designed to measure polarized light from the early Universe. Steffen Richter When the Harvard-Smithsonian Center for Astrophysics announced a press conference for a “Major Discovery” (capital letters in the original e-mail) involving an unspecified experiment, rumors began to fly immediately. By Friday afternoon, the rumors had coalesced around one particular observatory: the BICEP microwave telescope located at the South Pole. Over the weekend, the chatter focused on a specific issue: polarization in the Cosmic Microwave Background left over from the Big Bang. With the start of the press conference, it’s now clear that we’ve detected the first direct evidence of the inflationary phase of the Big Bang, in which the Universe expanded rapidly in size. BICEP, the Background Imaging of Cosmic Extragalactic Polarization experiment, was built specifically to measure the polarization of light left over from the early Universe. This light, known as the cosmic microwave background (CMB), encodes a lot of information about the physical state of the cosmos from its earliest moments. Most observatories (such as Planck and WMAP) have mapped temperature fluctuations in the CMB, which are essential for determining the contents of the Universe. Polarization is the orientation of the electric field of light, which conveys additional information not available from the temperature fluctuations. While much of CMB polarization is due to later density fluctuations that gave rise to galaxies, theory predicts that some of it came from primordial gravitational waves. Those waves are ripples in space-time left over from quantum fluctuations in the Universe’s earliest moments. Read 2 remaining paragraphs | Comments
