Red-letter day as giant black hole found

The black hole – which has a mass 20 times greater than the sun – is

also the second biggest ever found.

It was discovered by scientists from Sheffield University using the European Southern Observatory's Very Large Telescope in Chile.

The hole is in the spiral galaxy NGC 300, and is entwined with a star which will is also expected to become a black hole.

Sheffield University professor of astrophysics Paul Crowther said: "This is the most distant stellar-mass black hole ever weighed, and it's the first one we've seen outside our own galactic neighbourhood."

The black hole is next to a Wolf–Rayet star, which also has a mass of about 20 times as much as the sun. Wolf–Rayet stars are near the end of their lives and expel most of their outer layers into their surroundings before exploding as supernovae.

Prof Crowther added: "If the system survives this explosion, the two black holes will merge, emitting copious amounts of energy in the form of gravitational waves as they combine.

"It will take some few billion years until the actual merger, far longer than human timescales."