Closest black hole to Earth has two partners in surprising celestial marriage

WASHINGTON (Reuters) - Astronomers have spotted the closest black hole to Earth ever discovered and are surprised about its living arrangements - residing harmoniously with two stars in a remarkable celestial marriage that may end in a nasty breakup.

The black hole, at least 4.2 times the mass of the sun, is gravitationally bound to two stars in a so-called triple system roughly 1,000 light years from Earth, researchers said on Wednesday.

“Just around the corner” in cosmic terms, said Chile-based European Southern Observatory astronomer Thomas Rivinius, lead author of the study published in the journal Astronomy & Astrophysics.

A light year is the distance light travels in a year, 5.9 trillion miles (9.5 trillion km).

Black holes are extraordinarily dense objects possessing gravitational pulls so powerful that not even light can escape. Some are monstrous like the one at our galaxy’s center 26,000 light years from Earth that is four million times the sun’s mass.

Garden variety so-called stellar-mass black holes like the newly discovered one have the mass of a single star. This one probably began its life as a star up to 20 times the sun’s mass that collapsed into a black hole at the end of its relatively short lifespan.

This triple system, called HR 6819, can be seen from Earth’s southern hemisphere with the naked eye, in the constellation Telescopium. Until now, the closest-known black hole was one perhaps three times further away.