Space.com by By Elizabeth Howell 12/1/2019
Stellar-mass black holes aren't supposed to be so hefty.Scientists recently found a black hole so big that theory strains explain it, a new study reports.
A Chinese-led team discovered a stellar-mass black hole that appears to be 68 times heftier than Earth's sun — nearly three times bigger than the heaviest such objects should be, according to current thinking.
Calculations suggest that the Milky Way galaxy's stellar-mass black holes — which form after the violent deaths of giant stars — should top out at only 25 times the mass of the sun, the researchers said. (Supermassive black holes that lurk at the hearts of galaxies are much bigger, of course, containing millions or billions of solar masses.)
What's more, the huge black hole is also relatively close to Earth in cosmic terms. It sits at 13,800 light-years from our planet — a small fraction of the Milky Way's estimated diameter of 200,000 light-years.
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https://www.space.com/monster-black-hole-disovery-too-big-theories.html
