Astronomers find a mystery black hole in a star cluster.
Astronomers utilised the Hubble Space Telescope to detect evidence of an enigmatic black hole 8,000 times more massive than our sun.
Nature said that this black hole's size makes it special.
It's far larger than a typical black hole, which forms when a dead star collapses. However, it is not as large as supermassive black holes that lurk in galaxies and can hold hundreds of thousands to millions of suns.
Scientists have long sought medium-sized black holes like this one to understand how black holes arise and why some grow into giant monsters.
Scientists have failed to uncover solid examples of intermediate-size black holes, which are 100 to 100,000 times the mass of the sun, despite years of study.
"So people wonder, is it hard to find them because they're not there or because they're hard to detect?" According to Heidelberg-based Max Planck Institute for Astronomy's Maximilian Häberle.
He and colleagues recently searched Omega Centauri, a huge, brilliant star cluster, for one. This thick, spherical cloud of millions of stars is 17,000 light years away.
Since their gravity draws in everything, including light, black holes cannot be seen. But physicists can check if a black hole's gravity affects nearby objects, including stars.
The Hubble Space Telescope obtains annual photographs of the cluster's centre region, so the researchers knew the stars were being monitored.
Häberle says this is for technical reasons, to calibrate instruments.