A black hole and a star located about 8, 000 light years from Earth are moving each other in the constellation Cygnus. The black in system known as V404 Cygni has been relatively quiet since 1989.

In a statement, the European Space Agency (ESA) said after Alert Telescope on the Swift satellite detected an unusual burst of gamma rays coming from a well-known ‘sleeping’ black hole, the ESA started to monitor the event.

The agency said it used the gamma-ray observatory on its Integral satellite, to monitor the rare celestial event.

Erik Kuulkers, a project scientist at ESA, said the behavior of this source is extraordinary at the moment, with repeated bright flashes of light on duration shorter than an hour. These feature is something that is rarely seen in other black hole systems, Kuulkers said.

“In these moments, it becomes the brightest object in the X-ray sky—up to fifty times brighter than the Crab Nebula, normally one of the brightest sources in the high-energy sky”, he added.

As per experts, this black hole is thought to be approximately 12 times as massive as the sun. Being part of the Milky Way galaxy, it is located in the constellation Cygnus, which is Latin for ‘swan.’

The last time when astronomers saw the V404 Cygni binary system exhibit high amounts of activity was in 1989.

The ‘V’ in the name means it is a variable star that gives off periodic bursts of energy. These peaks and valleys of electromagnetic radiation are believed to be the result of material gradually accumulating in the disc surrounding the black hole, explains the ESA.