University of Minnesota co-leads team that discovers evidence of the “first tremors of the Big Bang”
Researchers gathered data with powerful telescope at the South Pole
March 17, 2014
Media note: U of M Professor Clem Pryke is available to Twin Cities media by phone today, after Noon CST, as he is in Boston for this announcement.
New data from a nationwide team of researchers gives direct evidence of the "first tremors of the Big Bang," providing groundbreaking new information about the earliest beginnings of our universe. The University of Minnesota co-led the research along with Harvard University, California Institute of Technology (Caltech), and Stanford University.
Almost 14 billion years ago, the universe we inhabit burst into existence in an extraordinary event that initiated the Big Bang. In the first fleeting fraction of a second, the universe expanded exponentially, stretching far beyond the view of our best telescopes. All this, of course, was just theory.
Researchers from the BICEP2 Collaboration today announced the first direct evidence for this cosmic inflation. Their data represents the first images of gravitational waves or ripples in space-time, and confirm a deep connection between quantum mechanics and general relativity. These waves have been described as the "first tremors of the Big Bang."
"This discovery gives us direct insight into the birth of the entire Universe in which we find ourselves," said Clem Pryke, a physics and astronomy professor in the University of Minnesota’s College of Science and Engineering and a co-leader of the BICEP2 collaboration, "It's a holy grail, and incredibly exciting!"
These groundbreaking results came from observations by the BICEP2 telescope of the cosmic microwave background—a faint glow left over from the Big Bang. Tiny fluctuations in this afterglow provide clues to conditions in the early universe. For example, small differences in temperature across the sky show where parts of the universe were denser, eventually condensing into galaxies and galactic clusters.
Since the cosmic microwave background is a form of light, it exhibits all the properties of light, including polarization. On Earth, sunlight is scattered by the atmosphere and becomes polarized, which is why polarized sunglasses help reduce glare. In space, the cosmic microwave background was scattered by atoms and electrons and became polarized too. "Our team hunted for a special type of polarization called ‘B-modes,’ which represents a twisting or "curl" pattern in the polarized orientations of the ancient light" said co-leader at Caltech Jamie Bock.
Gravitational waves squeeze space as they travel, and this squeezing produces a distinct pattern in the cosmic microwave background. Gravitational waves have a ‘handedness,’ much like light waves, and can have left- and right-handed polarizations. "The swirly B-mode pattern is a unique signature of gravitational waves because of their handedness. This is the first direct image of gravitational waves across the primordial sky," said co-leader at Stanford/SLAC Chao-Lin Kuo.
The team examined spatial scales on the sky spanning about one to five degrees (two to ten times the width of the full Moon). To do this, they traveled to the South Pole to take advantage of its cold, dry, stable air. "The South Pole is the closest you can get to space and still be on the ground," said project leader John Kovac, Harvard/CfA. "It’s one of the driest and clearest locations on Earth, perfect for observing the faint microwaves from the Big Bang."
They were surprised to detect a B-mode polarization signal considerably stronger than many cosmologists expected. The team analyzed their data for more than three years in an effort to rule out any errors. They also considered whether dust in our galaxy could produce the observed pattern, but the data suggest this is highly unlikely. "This has been like looking for a needle in a haystack, but instead we found a crowbar," Pryke said.
When asked to comment on the implications of this discovery, Harvard theorist Avi Loeb said, "This work offers new insights into some of our most basic questions: Why do we exist? How did the universe begin? These results are not only a smoking gun for inflation, they also tell us when inflation took place and how powerful the process was."
Technical details and journal papers can be found on the BICEP2 release website: http://bicepkeck.org
BICEP2 is the second stage of a coordinated program, the BICEP and Keck Array experiments, which has a co-PI structure. The four PIs are Clem Pryke (UMN), John Kovac (Harvard), Jamie Bock (Caltech/JPL), and Chao-Lin Kuo (Stanford/SLAC). All have worked together on the present result, along with talented teams of students and scientists. Other major collaborating institutions for BICEP2 include UCSD, UBC, NIST, University of Toronto, Cardiff, and CEA.
BICEP2 is funded by the National Science Foundation (NSF). NSF also runs the South Pole Station where BICEP2 and the other telescopes used in this work are located. The Keck Foundation also contributed major funding for the construction of the team’s telescopes. NASA, JPL, and the Moore Foundation generously supported the development of the ultra-sensitive detector arrays which made these measurements possible.