Historically, scientists have used light to study the cosmos. But now, scientists have a second way of looking at deep space: fluctuations in gravity called gravitational waves, which are ripples in the fabric of space and time created when two objects spiral together and collide.
For new URI physics lecturer Robert Coyne, it’s a childhood dream come true. “I used to wonder what it might’ve been like to witness the invention of the telescope, to get a chance to experience, firsthand, a brand new way of observing the universe,” says Coyne, 32. “I don’t have to wonder anymore.”
Coyne is a member of an exclusive club: the Laser Interferometer Gravitational-Wave Observatory, or LIGO, whose founders won the Nobel Prize in physics this fall. The international group of 1,200 scientists and technicians made headlines with the announcement that it had seen two neutron stars colliding 130 million light years away. Born from the explosive death of larger stars, neutron stars are city-sized stellar objects with at least the mass of the sun.
Gravitational waves were first predicted by Albert Einstein a century ago, but scientists thought they were too weak to be detected. After decades of effort, two LIGO detectors, in Livingston, La., and Hanford, Wash., were built to sense tiny fluctuations caused by these waves. In 2015, a ripple produced by the merger of two black holes was “heard’’ by LIGO, and since then three more pairs of black holes have been detected, says Coyne. But the recent observation of two merging neutron stars—also seen with telescopes—is particularly significant because it marks the first time scientists have detected gravitational waves and light from the same event.
“We can learn a lot from observing something with gravitational waves, and we can learn a lot from observing something with light,” says Coyne. “We can learn a lot more when we observe with both. This multi-messenger astronomy is the future of how we will unlock the universe’s greatest mysteries. Imagine what we’ll learn. We’ll find answers to questions we haven’t even thought to ask yet.” •