Black holes are the most extreme and least understood entities in the universe. With an inconceivable amount of matter packed into almost infinitely small space, black holes boast unimaginably powerful gravitational fields nothing, even light, can escape. Both of these supermassive black holes in the latest discovery have masses greater than 800 million times our sun. As the two gradually draw closer together in a cosmic death spiral, they will start sending gravitational waves rippling through space-time.
Those mysterious cosmic ripples will join the as-yet-undetected background noise of gravitational waves from other supermassive black holes
Even before the inevitable intergalactic crash, the gravitational waves radiating from the black hole pair will have previously detected from the mergers of much smaller black holes and neutron stars.
Dr Chiara Mingarelli, or the Flatiron Institute's Center for Computational Astrophysics said: "Supermassive black hole binaries produce the loudest gravitational waves in the universe.
" Gravitational waves from supermassive black hole pairs are a million times louder than those detected by LIGO. "
READ MORE: How to watch Hayabusa2 Asteroid Ryugu sample collection
The two supermassive black holes are particularly interesting b ecause they are approximately 2.5 billion light-years distant from Earth
This means the pair belongs to a universe 2.5 billion years younger than our own.
This is coincidentally the amount of time astronomers estimate the black holes will take
In the present-day universe, the black holes are already emitting these gravitational waves, but even at light speed the waves will reach Earth for billions of years.
READ MORE : NASA warning as 'world's most dangerous glacier' to COLLAPSE
This discovery of a black hole collision will help scientists estimate how many nearby supermassive black holes are emitting gravitational waves that we could detect right now.
Detecting the gravitational wave background will help resolve some of the biggest unknowns in astronomy, such as how often galaxies merge and whether supermassive black hole pairs m erge or become trapped in an eternal dance with each other.
Professor Jenny Greene of Princeton University, the study's co-author, said: "It's a major embarrassment for astronomy that we don't know if supermassive black holes merge. 1
READ MORE: Mars MYSTERY: NASA probes strange impact crater on red planet
Theoretical studies suggest black holes usually stall at roughly 3.2 light-years apart.
This slowdown lasts almost indefinitely and is known as the final parsec problem.
In this scenario, only very rare groups of three or more supermassive black holes result in mergers.
Astronomers can't just look for stalled pairs because long before the black holes are 1 parse apart, they are too close to distinguish as two separate objects. ]> Moreover, the black holes do not produce strong gravitational waves until they overcome the final parsec hurdle and get closer together.