Did astronomers see the light from two black holes colliding for the first time?
So far the only way astronomers have been able to ‘observe’ black holes colliding is by detecting the resulting gravitational waves. Since the first detection in 2015, scientists have observed gravitational waves, working to understand their origins. Because black holes have a gravitational pull so strong that not even light can escape, they’re difficult to observe, and astronomers have yet to visually identify a collision between two black holes… that is, until now.
While black holes are dark, there are theories that suggest collisions or mergers between black holes could produce a light signal through the material that surrounds them by causing matter to radiate. A team of astronomers using the Zwicky
Transient Facility (ZTF) at the Palomar Observatory in California think they may have detected such a light signal. The gravitational wave created by the merger was detected on 21 May 2019 by two different gravitational-wave detectors: Virgo and the Laser Interferometer Gravitational-wave Observatory (LIGO). The wave they detected stems from a collision event dubbed GW190521g that the team thinks could possibly be from two black holes. With this detection, a team of astronomers used the ZTF to peer out into the cosmos and search for light signals from the collision. If confirmed, this would be the first time visible light would be used as evidence of two black holes colliding and creating a gravitational wave.