Scientists find black holes ‘close’ to Earth and on a collision course

About 1,600 light-years away, two supermassive black holes are expected to collide in about 250 million years. They are the closest pair to Earth, and the distance between them is the shortest distance ever found between two supermassive black holes.

The largest has a mass of 154 million times the mass of the Sun, while the smallest has a mass of 6.3 million times the mass of the Sun.

It was found by researcher Karina Vogel and colleagues at the University of Strasbourg, France. Scientists used the array of telescopes from the Very Large Telescope Observatory, located in Chile. The results were published in the academic journal Astronomy and astrophysics.

Black holes are located in Jacacia called NGC 7727, which is about 89 million light-years from Earth. The largest of them is located in the center of the galaxy. The smallest, about 1,600 light-years from the first, probably belonged to a smaller galaxy, which NGC 7727 swallowed billions of years ago.

Researchers believe that within 250 million years, the black holes will collide and merge, becoming one supermassive black hole. Scientists have now been able to find them because the holes are five times closer to Earth than any other supermassive pair.

According to Voggel, scientists usually cannot observe this stage of a black hole merging. “These astronomical processes take billions of years, so we can’t track them when they happen, but we do track this process during the merger,” he says.

According to the research, it was possible to identify black holes from the rapid movements of nearby stars – not in the most common way, by observing the light that some black holes emit as they absorb matter around them. “In this case, black holes are silent,” Vogel says. “That’s why these were ignored.”

The scientist believes that there may be many other “hidden” black holes outside the centers of galaxies. She estimates that if we count secondary black holes (outside centers like this one are smaller), the number of known supermassive black holes in the universe would increase by up to 30%.