Gravity Waves From Big Bang Detected
The Background Imaging of Cosmic Extragalactic Polarization 2 (BICEP2) experiment at the South Pole found a pattern called primordial B-mode polarization in the light left over from just after the big bang, known as the cosmic microwave background (CMB). This pattern, basically a curling in the polarization, or orientation, of the light, can be created only by gravitational waves produced by inflation. “It looks like a swirly pattern on the sky,” says Chao-Lin Kuo, a physicist at Stanford University, who designed the BICEP2 detector. “We’ve found the smoking gun evidence for inflation and we’ve also produced the first image of gravitational waves across the sky.”
Such a groundbreaking finding requires confirmation from other experiments to be truly believed, physicists say. Nevertheless, the result has won praise from many leaders in the field. “There’s a chance it could be wrong, but I think it’s highly probable that the results stand up,” says Alan Guth of the Massachusetts Institute of Technology, who first predicted inflation in 1980. “I think they’ve done an incredibly good job of analysis.” The BICEP2 detectors found a surprisingly strong signal of B-mode polarization, giving them enough data to surpass the “5-sigma” statistical significance threshold for a true discovery. In fact, the researchers were so startled to see such a blaring signal in the data that they held off on publishing it for more than a year, looking for all possible alternative explanations for the pattern they found. Finally, when BICEP2’s successor at the same location, the Keck Array, came online and began showing the same result, the scientists felt confident. “That played a major role in convincing us this is something real,” Kuo says.
More: Gravity Waves From Big Bang Detected - Scientific American