Scientists recently found a black hole so big that current knowledge says it shouldn’t exist. An international team of scientists led by China say they have discovered a stellar-mass black hole with a mass 70 times greater than the sun. That is nearly three times bigger than what current thinking says the heaviest stellar-mass black hole should be. The study has been published online in the journal Nature.
According to NASA, stellar-mass black holes are the remnants of stars that have died. They are the most common type of black hole and typically have the mass of 10 to 24 suns. Calculations suggest that stellar-mass black holes in the Milky Way galaxy should top out at 25 times the mass of the sun. Scientists have found, identified, and measured about two dozen stellar black holes.
The newly discovered black hole may be the largest of its kind. Liu Jifeng, a professor at the National Astronomical Observatory of China and the head researcher on the study, said of the new finding, “Black holes of such mass should not even exist in our galaxy, according to most of the current models of stellar evolution.”
Liu’s team made their discovery using gravitational observations from China’s Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST). The team looked for stars that were orbiting some invisible object, being pulled in by its gravity, and found a star eight times the mass of the sun that appeared to orbit a black hole every 79 days. This finding was backed up with data from two other telescopes.
Scientists are now trying to determine how the newly discovered black hole got so large. Current theories include that it was formed from the collapse of more than one star and that it could be two smaller black holes orbiting each other. There is also the theory that it was caused by a “fallback supernova” – when a supernova ejects material that then falls back into the supernova, creating a black hole. Scientists have never been able to prove or observe this fallback formation, but say it is theoretically possible.