Section: News

Making waves

Making waves

When a group of scientists announced on Feb. 11 that their group had detected gravitational waves — supporting predictions Albert Einstein made in his theory of general relativity just over a century ago — two Kenyon faculty members were among them.

Assistant Professors of Physics Madeline and Leslie Wade joined over a thousand scientists working at the Laser Interferometer Gravitational-Wave Observatory (LIGO) that observed gravitational waves given off by a compact binary coalescence — the technical term for two black holes merging — 1.3 billion years ago. This event, called GW150914, is the first binary coalescence to be detected.

“To see how excited the world got about this was beyond, I think, any of our expectations,” Madeline said. Madeline joined the project while in graduate school at the University of Wisconsin-Milwaukee, and has worked to develop methods for detecting astrophysical events that could emit gravitational waves.

She described general relativity as predicting that masses bend the fabric of space-time, and gravitational waves as ripples in that surface that cause a slight change in distances between objects. For example, gravitational waves would alter the distance between the Sun and Earth by the width of a human hair.

In an experiment, a beam of light was split into two, and bounced off mirrors. LIGO researchers theorized that, because the speed of light is constant, these beams should reunite at the same point. The LIGO detector was set up so the branches of light would cancel each other out if they recombined in such a manner, and emit no light. If one path was longer than the other due to gravitational waves, the waves would not return to the original point at the same time, and light would appear.

Madeline compared the importance of the discovery to Galileo’s first visible light telescope, because it will allow scientists to see gravitational waves, which previously were beyond the reach of observation. Scientists had already seen indirect evidence of gravitational waves, but Leslie said this discovery heralded the start of a new field: gravitational wave physics.

The discovery may also help scientists better understand how black holes form.

“We had estimates for how often we thought black holes might merge, but it was based on limited data,” Leslie said. “Until you start measuring things, you have no idea how close your theory is.”

Leslie said the next step will be a long-term search for gravitational waves that will likely open “a new window on our universe.” The Professors Wade are hoping to involve Kenyon in  a team called Arecibo Remote Command Center (ARCC) that will allow undergraduates to look for a different frequency of gravitational waves by studying regular radio emissions from pulsars.

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