Researchers use telescopes at Antarctica's South Pole to study the cosmic microwave background, the oldest light in the universe, to understand the early moments after the Big Bang.
The CMB was emitted about 380,000 years after the universe's first second. During that first second, the universe expanded from smaller than an electron to more than 100 trillion miles wide in a period called inflation. As the universe has continued expanding since then, the CMB's wavelengths have stretched from visible light to microwaves, making it detectable only with radio telescopes today.
The South Pole Telescope and BICEP experiments examine patterns in the CMB's polarization, the orientation of its light. Scientists search for a particular signal called the B-mode polarization, which could reveal primordial gravitational waves. These waves would indicate that gravity existed and worked during the universe's earliest quantum fluctuations.
"It's one of the ways that we can understand gravity at these very extreme scales," said Kimmy Wu, an assistant professor at the California Institute of Technology. "The fact that there could be primordial gravitational waves means that at the early fraction of a second when the universe was quantum fluctuations, gravity worked."
John Carlstrom, a professor at the University of Chicago and director of the SPT, led the team that detected the CMB's polarization in 2002. Combining data from multiple telescopes allows researchers to sort through competing signals and search for evidence supporting inflation theory.