Einstein was right. In the Feb. 11, 2016, issue of Physical Review Letters, a team of scientists announced they’d heard and recorded, for the first time, a long-predicted, but elusive phenomenon that’s sent ripples of excitement through the globe, including the Utah State University community.
On Sept. 14, 2015, the massive Laser Interferometer Gravitational-Wave Observatory, known as “LIGO,” detected gravitational waves that vibrated antennas at its facilities in Hanford, Washington and Livingston, Louisiana. The observatory detected a second signal on June 15, 2016. As Einstein imagined on paper 100 years ago, the waves were created by the collision of two black holes whirling through space more than a billion light-years away.
“I was actually asleep when the waves were detected at 5 a.m. on Sept. 14th,” says USU physics and mathematics alum Sydney Chamberlin ‘09, who joined the LIGO Scientific Collaboration during graduate studies at the University of Wisconsin-Milwaukee. “I woke up to a flurry of email messages.”
Initially, Chamberlin, who completed her doctorate in 2015 and is a postdoc at Penn State, thought the detected waves were routine “blind, injected signals” the researchers used to test the monitoring system.
“When my colleagues and I received confirmation later in the day that LIGO had indeed detected the waves, we were beyond excited,” says the 2008 Goldwater honorable mention recipient and 2009 Rhodes Scholar finalist. “But we had to sit on the information until the February 2016 official announcement.”
The observatory’s dual facilities, which operate in unison, are located more than 1,800 miles apart to ensure local vibrations are not mistaken for signals from gravitational waves. Each facility consists of an L-shaped, ultra-high vacuum system, with steel vacuum tube arms, encased in concrete, extending 2.5 miles in length. Laser beams shine down each arm from the crux of the “L” and are reflected back by mirrors at the end of each arm. If reflected beams from both arms return at the same time, it’s an indication no wave has been detected. However, a slight difference indicates a galactic disturbance from space.
“When the gravitational waves passed through the observatory, one arm stretched and the other one compressed,” says Maria Rodriguez, assistant professor in USU’s Department of Physics. “And so, the lasers that were pointing and measuring the distance between these two arms are actually measure the deformation, or the compression and stretching, of each arm.”
Chamberlin and Rodriguez are among a bevy of Aggie scientists who are LIGO collaboration members or involved in gravitational waves research and teaching, including USU Physics faculty members Oscar Varela, Charlie Torre and David Peak, along with former USU Physics faculty member and Science Unwrapped founder Shane Larson.
Peak calls capture of the “almost unimaginably weak” gravitational ripples the most sophisticated engineering feat in human history.
“That gravitational waves have finally been directly measured is not the big deal,” he says. “What’s amazing about this discovery is the waves could be detected at all with earth-bound instruments and the relatively small size of the orbiting bodies that produced them.”
Detecting the waves in this manner, Peak says, provides a whole new way of probing the structure of matter that, until now, could not be directly studied.
Among the LIGO founders credited with the breakthrough is Logan, Utah native Kip Thorne, son of renowned USU faculty member and administrator D. Wynne Thorne and USU lecturer Alison Thorne. The Caltech physicist reported to media, “We’re seeing what I like to call the warped time of the universe for the first time.”
USU Science Dean and physicist Maura Hagan marvels at the discovery and its meaning for the scientific community.
“When I first heard the news, I thought how lucky we are to be alive at a time when LIGO scientists confirmed Einstein’s prediction,” she says. “It’s important for our students to know this long-awaited discovery was built on the persistent efforts of a team of talented scientists from multiple institutions, which relied on considerable investment from the National Science Foundation and international partners.”
Chamberlin, who returned to Utah State Oct. 14 to deliver a Science Unwrapped talk, says her classroom and undergraduate research experiences prepared her well for rigorous graduate studies and her work with LIGO.
“I had wonderful mentors, including Charlie Torre and David Peak in Physics, Ian Anderson and Mark Fels in Mathematics and Shannon Peterson in Political Science,” she says. “They’re not only great teachers and researchers; they gave me the confidence to step out of my comfort zone and aim higher.”