Long-sought hum of gravitational waves from giant black holes heard for first time
https://www.science.org/content/article/long-sought-hum-of-gravitational-waves-from-giant-black-holes-heard-for-first-time
By Adam Mann, Science.
Excerpt: By turning networks of dead stars into galaxy-size gravitational wave detectors, radio astronomers have tuned into the slowly undulating swells in spacetime thought to arise from pairs of supermassive black holes (SMBHs) that are about to collide. In a simultaneous announcement today, five separate international teams said that after nearly 20 years of effort they had found evidence for these gravitational waves. They are far longer than the waves first captured by ground-based detectors in 2015, which emanate from collisions of star-size objects. The findings not only open up a new window in gravitational wave astronomy, but will also help researchers answer questions about the origin and evolution of SMBHs, objects that sit at the center of galaxies and weigh as much as billions of Suns....