The job of astronomers is as intriguing as it is frustrating. There are days when they find nothing of interest despite putting in a lot of effort and resources, and then there are days when they discover celestial objects or events that have the potential to change the course of history, or rather the future. Astronomers using the European Southern Observatory’s Very Large Telescope (ESO’s VLT) have had a similar experience recently. They have found the closest pair of supermassive black holes to Earth ever observed. The two objects, having a separation much smaller than any other pair of supermassive black holes previously discovered, are likely to merge into one giant black hole, they say.

A black hole is a place in space where gravity is so strong that nothing, not even light, can get out of it. The heightened gravitational force of a black hole is a result of matter being squeezed into a tiny space. And, we are not able to see black holes because they do not let the light pass through them, but space telescopes equipped with special tools can find black holes. Black holes are usually formed by dying stars.

The two supermassive black holes are located in the galaxy NGC 7727 in the constellation Aquarius, which is about 89 million light-years away from Earth, the closest to us yet. The previous record for the closest pair of supermassive black holes was 470 million light-years away from Earth. Also, the new pair of black holes are only 1600 light-years apart in the sky, according to the study published in Astronomy and Astrophysics.

“It is the first time we find two supermassive black holes that are this close to each other, less than half the separation of the previous record holder,” Karina Voggel, the lead author of the study, was quoted as saying in a report by the European Southern Observatory.

The bigger black hole, at the centre of NGC 7727, has a mass almost 154 million times that of the Sun, while its companion is 6.3 million solar masses.

Voggel’s associate and study co-author Holger Baumgardt, a professor at the University of Queensland, Australia, said that the small separation and velocity of the two black holes indicate that they will merge into one monster black hole, probably within the next 250 million years.