Skip to main content

Closest pair of supermassive black holes is merging into one mega black hole

At the heart of almost every galaxy, including our own, is a monstrously large black hole with mass millions or billions of times that of the sun. These supermassive black holes are generally lonely beasts, but astronomers have recently discovered the closest-ever pair of them which will eventually merge into one even larger black hole.

This image shows close-up (left) and wide (right) views of the two bright galactic nuclei, each housing a supermassive black hole, in NGC 7727, a galaxy located 89 million light-years away from Earth in the constellation Aquarius. Each nucleus consists of a dense group of stars with a supermassive black hole at its centre. The two black holes are on a collision course and form the closest pair of supermassive black holes found to date. It is also the pair with the smallest separation between two supermassive black holes found to date — observed to be just 1600 light-years apart in the sky. The image on the left was taken with the MUSE instrument on ESO’s Very Large Telescope (VLT) at the Paranal Observatory in Chile while the one on the right was taken with ESO's VLT Survey Telescope.
Close-up (left) and wide (right) views of two bright galactic nuclei, each housing a supermassive black hole. ESO/Voggel et al.; ESO/VST ATLAS team. Acknowledgement: Durham University/CASU/WFAU

The galaxy NCG 7727 is host to the black hole pair, which is located around 89 million light-years away from Earth — far closer than the closest previously recorded pair, which is 470 million light-years away. The recently discovered pair are very close together by black hole standards, at a distance of 1,600 light-years, and are thought to have been brought together by two galaxies merging.

Recommended Videos

“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,” said lead author Karina Voggel, an astronomer at the Strasbourg Observatory in France. The team detected the pair using the Multi-Unit Spectroscopic Explorer (MUSE) instrument on the European Southern Observatory’s Very Large Telescope, which was able to measure the masses of the two black holes by observing how they affected the movements of the stars around them.

They found that the larger of the black holes has a mass 150 million times that of the sun, and its smaller companion has a mass 6.3 million times that of the sun. The fact that the two are so close together (relatively speaking) means it is likely that they will merge together in the future.

“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,” said co-author Holger Baumgardt, a professor at the University of Queensland, Australia.

Georgina Torbet
Georgina has been the space writer at Digital Trends space writer for six years, covering human space exploration, planetary…
Record-breaking supermassive black hole is oldest even seen in X-rays
Astronomers found the most distant black hole ever detected in X-rays (in a galaxy dubbed UHZ1) using the Chandra and Webb telescopes. X-ray emission is a telltale signature of a growing supermassive black hole. This result may explain how some of the first supermassive black holes in the universe formed. This composite image shows the galaxy cluster Abell 2744 that UHZ1 is located behind, in X-rays from Chandra (purple) and infrared data from Webb (red, green, blue).

Astronomers recently discovered the most distant black hole ever observed in the X-ray wavelength, and it has some unusual properties that could help uncover the mysteries of how the largest black holes form.

Within the center of most galaxies lies a supermassive black hole, which is hundreds of thousands or even millions or billions of times the mass of our sun. These huge black holes are thought to be related to the way in which galaxies form, but this relationship isn't clear -- and how exactly supermassive black holes grow so massive is also an open question.

Read more
This peculiar galaxy has two supermassive black holes at its heart
The billion-year-old aftermath of a double spiral galaxy collision, at the heart of which is a pair of supermassive black holes.

As hard as it is to picture, with billions or even trillions of galaxies in the universe, entire galaxies can collide with each other. When that happens, one galaxy can be destroyed or the two can merge into one. But even in the case of galaxy mergers, the effects of the collision are often visible for billions of years afterward.

That's shown in a recent image taken by the Gemini South observatory, which shows the chaotic result of a merger between two spiral galaxies 1 billion years ago.

Read more
Swift Observatory spots a black hole snacking on a nearby star
Swift J0230 occurred over 500 million light-years away in a galaxy named 2MASX J02301709+2836050, captured here by the Pan-STARRS telescope in Hawaii.

Black holes can be hungry beasts, devouring anything that comes to close to them, including clouds of gas, rogue planets, and even stars. When stars get too close to a black hole, they can be pulled apart by gravity in a process called tidal disruption that breaks up the star into streams of gas. But a recent discovery shows a different phenomenon: a black hole that is "snacking" on a star. It's not totally destroying the star, but pulling off material and nibbling at it on a regular basis.

Black Hole Snack Attack

Read more