Generally, Black Holes are nearly impossible to see as nothing can pass through them, not even light. So when an event like black hole collision occurs we won’t expect to see it but recently scientists observed a new phenomenon. In May 2019 an event occurred in which two supermassive black holes collide and produced a very bright flare of light. The event is named S190521g. It occurred some 4 billion light-years away from earth.
How scientists observed the phenomenon
Black Hole collisions are so powerful that they ripple in space-time and send gravitational waves across the universe. LIGO facilities in the US and the Virgo observatory in Italy detected those gravitational waves. The scientists analyzed those signals and confirmed there is a black hole collision at the location. At the same time, an observatory telescope in California spot luminous object in the sky. Astronomers traced backed the bright flash signals to the center of the distant galaxy, where a black hole collision events took place.
When two black holes collide the combined force sent the merged object hurtling out of the accretion disk and heat it up. The heat up material produced much bright light, that later picked up by the observatory telescope, on earth.
“The flare occurred on the right timescale, and in the right location, to be coincident with the gravitational-wave event. In our study, we conclude that the flare is likely the result of a black hole merger, but we cannot completely rule out other possibilities,” Matthew Graham, lead author of the research said.