The first direct detection of gravitational waves marks a major advancement for physics and astronomy. Predicted by physicist Albert Einstein 100 years ago, gravitational waves were finally detected by the highly sensitive instruments known as Laser Interferometer Gravitational-Wave Observatory (LIGO).
Professor Charles Evans is a gravitational theorist in the UNC Department of Physics and Astronomy. Staff Writer CJ Farris spoke with Evans about the discovery.
Daily Tar Heel: What are gravitational waves?
Charles Evans: It’s a traveling disturbance in space and time. It’s a local warping and stretching and compression of space. We put a word on it in physics, we call it strain.
DTH: So why is this the first time we’ve directly detected gravitational waves?
CE: It just goes back to how incredibly weak gravity is. The gravitational force is really weak, the only reason why we are stuck to the Earth is just because there’s this huge amount of mass below us ... So what was required was to just reach the technological level. The technology in this experiment is extraordinary.
DTH: Can you talk about the origins of these gravitational waves?
CE: So we’ve seen black holes, but this is the first time where we’ve, in essence, seen two black holes orbiting around each other and catching them right at the end when their orbit is so tight that they are orbiting around each other 75 times a second, and then the last bit of energy is taken out of the orbit and the two merge together and become one large black hole.
DTH: Was this find expected?