Hello, Universe

After decades of dreaming the Laser Interferometer Gravitational-Wave Observatory (LIGO) into existence, nine years of initial operations, and a five-year period spent installing equipment with upgraded sensitivity, LIGO’s Caltech-led research team resumed listening to the universe in May 2015. To their immense surprise, detection came almost immediately. At 5:51 a.m. EST on Monday, September 14, 2015, the twin LIGO detectors observed gravitational waves.

“It seemed completely unbelievable,” says Fiona Harrison, holder of the Kent and Joyce Kresa Leadership Chair in the Division of Physics, Mathematics and Astronomy (PMA). Above and beyond the fact of the detection—astonishing in its own right—she marveled at the nature of the event that was observed. “We didn’t expect to find merging black holes. We didn’t know for sure that those systems existed.”

Beyond the massive implications this breakthrough has for the future of observing and understanding our universe, it illustrates the importance of taking big risks with a hope—but no promise—of success.

“Caltech had the wherewithal to invest in the theory of relativity,” says Harrison, who is also the Benjamin M. Rosen Professor of Physics at Caltech and the principal investigator for NASA’s Nuclear Spectroscopic Telescope Array (NuSTAR). “It meant measuring the distance between two mirrors with a precision that is one-tenth the diameter of a nucleus. Any other place would have said, ‘This is insane.’ ”

When Caltech’s Kip Thorne (BS ’62) and Ronald Drever, along with MIT’s Rainer Weiss, first laid the groundwork for LIGO in the 1980s, Caltech invested using flexible funds. Such funds were a rarity then, and they are a rarity now. But at Caltech, they are becoming less rare—and it’s becoming clearer that human understanding depends on them. That initial seed money led to proofs of concept that spurred the National Science Foundation to invest in LIGO, its largest project yet, to the tune of $1 billion.

“The detection of gravitational waves has opened a whole new view on the universe.”
- Fiona Harrison

The road to detecting gravitational waves involved hundreds of researchers, theorists, experimentalists, and atomic and molecular physicists, Harrison says. It also relied on important principles elucidated by Caltech physicists working at the quantum level.

Harrison and other Caltech division chairs are perfectly positioned to help researchers get visionary projects like this off the ground. Flexible funds such as those available from the Kresa leadership chair allow her to think broadly about the future of discovery for her division.

Harrison is a visionary in her own right, having led many field-shifting projects since joining Caltech’s faculty in 1995. Her work focuses on understanding some of the hottest, densest, and most energetic phenomena in the universe. She also helps develop advanced detectors and instrumentation for future space missions, including NuSTAR, the first orbiting telescopes to focus light in the high-energy x-ray region of the electromagnetic spectrum. She was named the Kent and Joyce Kresa Leadership Chair in PMA in 2015. Under her leadership, her division is poised to continue making giant leaps in understanding our universe.

“The detection of gravitational waves has opened a whole new view on the universe,” Harrison says. “Funds provided by the Kresa chair are going to enable future projects of this caliber. I’m really excited about the prospect that we will be studying other worlds—studying planets around stars [elsewhere in] our galaxy that may be like Earth.”

Giving Priorities