One of our black holes is missing.
Every galaxy ever observed – including our own – is entered around a supermassive black hole. Stars orbit them in much the same way as planets orbit stars.
The galaxy cluster Abell 2261, which is located about 2.7 billion light years from Earth, is one of the largest objects of its kind and astronomers fully expected to see a gigantic black hole at its heart.
But despite searching with NASA's Chandra X-ray Observatory and Hubble Space Telescope, they can find no sign of it.
The object at Abell 226’s centre should weigh at least 3 billion and as much as 100 billion times the mass of the Sun – but it’s just not there.
The fact that there is a dense concentration of stars near the centre of the cluster seems to rule out the possibility that there is a black hole in Abell 2261 that is somehow invisible..
A team led by Kayhan Gultekin from the University of Michigan in Ann Arbor have theorised that Abell 2261 was formed by the collision of two smaller galaxies and after their central black holes collided and merged the new supermassive black hole was somehow ejected into deep space.
Even that’s an unproven theory – “it is not known whether supermassive black holes even get close enough to each other to produce gravitational waves and merge; so far, astronomers have only verified the mergers of much smaller black holes," NASA officials said in a statement.
The evidence scientists need could be provided by the James Webb Space Telescope, which is expected to launch in October.
The $8.8 billion James Webb telescope, a spiritual successor to Hubble which will use four ultra-powerful instruments to probe the Universe’s deepest secrets, could yet find a previously undetected black hole lurking at the centre of the galaxy cluster.
If not, say the NASA experts, ”then the best explanation is that the black hole has recoiled well out of the centre of the galaxy.”