Interferometric gravitational wave detectors

Interferometric gravitational wave detectors, like LIGO and Virgo, detect ripples in spacetime caused by massive cosmic events, such as merging black holes. They use laser beams split and sent down long, perpendicular arms. As gravitational waves pass through, they stretch one arm while compressing the other, altering the time it takes for light to travel. By measuring these tiny changes in distance—much smaller than a proton—scientists can infer the waves' properties, helping us understand the universe's most violent phenomena and confirming key predictions of Einstein's theory of general relativity.