Gravitational wave from merger of two black holes over 7 billion years ago detected

A team of scientists on Wednesday announced that a gravtational wave generated by the merger of two black holes about 7 billion years ago when the the universe was about half its age, has been detected. 

The signal from the wave, labeled GW190521, was first detected on May 21, 2019 with the National Science Foundation's Laser Interferometer Gravitational-wave Observatory (LIGO) and the Advanced Virgo detector at the European Gravitational Observatory (EGO). 

The LIGO team explains, every gravitational wave signal detected so far has been from a "binary merger," either two black holes or two neutron stars. The collaboration further reports this merger "appears to be the most massive yet" and the two black holes that merged had masses "about 85 and 66 times the mass of the sun."

“This doesn’t look much like a chirp, which is what we typically detect,” says Virgo member Nelson Christensen, a researcher at the French National Centre for Scientific Research, said in a press release. “This is more like something that goes ‘bang,’ and it’s the most massive signal LIGO and Virgo have seen.”

The brief signal detected by scientists lasted less than a tenth of a second, the LIGO Scientific Collaboration (LSC) reported. 

Findings on the discovery were published in Physical Review Letters. A report in The Astrophysical Journal Letters details the signal's implications. 

Black holes that have been previously observed fit into two categories.

They are either stellar-mass black holes, "which measure from  a few solar masses up to tens of solar masses," the ones thought to form when massive stars die; or they are supermassive black holes, the ones that are hundreds of thousands to billions of times larger than the sun, according to the LIGO Scientific Collaboration.