We may soon be using GWs as routinely as radio waves and X-rays are used todayby Philip Ball / October 3, 2017 / Leave a comment
This year everyone with their eye on the ball predicted the Nobel prize in physics correctly. It was obvious that it must be awarded to the researchers responsible for the epoch-making detection of gravitational waves (GWs), announced in February 2016—just weeks too late to qualify for last year’s prize.
The discovery was both an experimental confirmation of a prediction of Albert Einstein’s century-old theory of general relativity, which furnishes the current view of what gravity is, and the beginning of a new type of astronomy that uses GWs to look at extreme astrophysical events much as astronomers already use radio waves, light, X-rays and other types of electromagnetic radiation.
Gravitational waves—ripples in spacetime, in the now clichéd argot—big enough to be detected across the galaxy are generated by unimaginably violent processes such as the merging of two black holes. Masses distort spacetime much as sleeping bodies distort the flat surface of a mattress—that distortion, in Einstein’s theory, changes the trajectories of objects in ways that we conventionally describe as the result of the force of gravity. But a ruction like colliding black holes leaves spacetime “ringing,” the ripples spreading through space until they are detected on Earth as a tiny, ephemeral change in the path length of light beams reflected from mirrors along the kilometer-scale arms of GW detectors.