MIT students attempting to detect first gravitational waves created in the universe

After the Big Bang, a series of first gravitational waves rippled through the universe, which caused the universe to expand.

These same primordial gravitational waves still echo through the universe after approximately 13.8 billion years.

Graduate students at MIT have been working on ways to detect these primordial gravitational waves, which are faint compared to the ripples of present-day gravitational waves produced by current events such as black holes and neutron stars colliding, MIT said in a Dec. 9 report on its website. Published in Physical Review Letters, the students have been using LIGO and other detectors to find the signals' primordial gravitational waves.

"Gravitational waves are being detected on an almost daily basis by LIGO and other gravitational-wave detectors, but primordial gravitational signals are several orders of magnitude fainter than what these detectors can register," the MIT report said. "It's expected that the next generation of detectors will be sensitive enough to pick up these earliest ripples,"

New detectors able to find fainter signals should help uncover the signs from the primordial gravitational waves, patterns and how they drove the universe to inflation.

"If the strength of the primordial signal is within the range of what next-generation detectors can detect, which it might be, then it would be a matter of more or less just turning the crank on the data, using this method we've developed," Sylvia Biscoveanu, a graduate student in MIT's Kavli Institute for Astrophysics and Space Research, said in the MIT report. "These primordial gravitational waves can then tell us about processes in the early universe that are otherwise impossible to probe."

Researchers are working on a new approach to find the "conversations" of the astrophysical foreground and patterns of primordial gravitational wave signals. This model was used to detect patterns, black hole mergers and other information to help find information on the primordial background.

"We were able to fit both the foreground and the background at the same time, so the background signal we get isn't contaminated by the residual foreground," Biscoveanu said in the MIT report.