Via Megan Gannon:
Researchers had already detected this polarized light in one pattern, known as “electric” or E-mode polarization. But using the South Pole Telescope in Antarctica and the European Space Agency’s Herschel space observatory, researchers for the first time detected polarized light from the cosmic microwave background in the “magnetic” or B-mode.
The observed B-mode pattern arose from gravitational lensing, in which light gets bent and deflected by massive cosmic objects such as galaxy clusters and lumps of mysterious dark matter, researchers said. But there is another way to produce B-modes: primordial gravitational waves produced during the earliest moments of the universe, when it was in its rapid “inflation” phase, mere trillionths of a second after the big bang.
During inflation, the idea goes, the universe expanded faster than the speed of light, doubling in size 100 times or more in just a few tiny fractions of a second. (Einstein’s theory of special relativity holds that no information or matter can travel faster than light through space, but this rule does not apply to inflation, which was an expansion of space itself.)
The new detection should provide a baseline to aid future efforts to measure B-modes produced by gravitational waves, which in turn could reveal a great deal about how our universe grew in its earliest moments, researchers said.
“This measurement was made possible by a clever and unique combination of ground-based observations from the South Pole Telescope — which measured the light from the big bang — with space-based observations from Herschel, which is sensitive to the galaxies that trace the dark matter which caused the gravitational lensing,” Herschel researcher Joaquin Vieira, of the California Institute of Technology and the University of Illinois at Urbana-Champaign, explained in a statement.
And there you go. If you’re really into the technical papers, a preprint version is available from ArXiv.