Gravitational Waves

Einstein had predicted gravitational waves as part of his General Theory of Relativity. Now, almost a century later, the first detection of a gravitational wave has been reported. It was announced today by the Harvard-Smithsonian Center for Astrophysics. The Plank space observatory has been studying the CMB since 2009, and astronomers hoped it would be able to provide the evidence, but the results came from the Background Imaging of Cosmic Extragalactic Polarization (BICEP) detector located at the South Pole.

The Cosmic Microwave Background (CMB) is the left over radiation from a four hundred thousand years after the Big Bang. In the mid 1990s astrophysicists proposed that the polarization of the CMB could provide evidence for gravitational waves from the birth of the universe

The discovery of the CMB polarization by gravitational wave settles the debate over whether the early universe was inflationary.  An inflationary period would produce larger gravitational waves than if there was no inflationary period. But even most inflationary models do not predict a gravitational wave large and polarizing enough to be detected by BICEP. The signal from BICEP is so strong, that it makes many of the inflationary models of the early universe unsupported, and completely contradicts the non-inflationary versions.

The paper can be read here http://bicepkeck.org/b2_respap_arxiv_v1.pdf

Sources:
http://news.yahoo.com/major-discovery-smoking-gun-universes-incredible-big-bang-145912987.html

http://www.space.com/25078-universe-inflation-gravitational-waves-discovery.html

http://en.wikipedia.org/wiki/Cosmic_microwave_background