A black hole that trumps all others in size was detected by two NASA satellites and announced by researchers, led by Andrea Prestwich at the
Sitting 1.8 million light years away in the constellation Cassiopeia, this new record-breaker is a black hole of the stellar-mass variety, meaning it was formed when a massive star died and collapsed inward upon itself.
The team at the Harvard-Smithsonian Center for Astrophysics was able to estimate the black hole’s mass because it orbits another star that ejects gas, which spirals toward the black hole (above), heats up and emits revealing X-rays before being gobbled up by the hole.
Some suspected that the black hole bulked up as a result of an insatiable appetite, slurping up whatever was within its vicinity. But the study found that it has only gained one or two solar masses since its metamorphosis from star to black hole. Instead of shedding pounds, as most stars do before imploding, this one carried its mass into its black hole afterlife. Experts say the black hole was "born fat, it didn't grow fat."
The finding expands researchers’ understanding of just how massive a black hole can be. "We now know that black holes that form from dying stars can be much larger than we had realized," Prestwich says.
( This artist's conception shows the biggest stellar-mass black hole, upper left, which weighs 24 to 33 times as much as the Sun. It is pulling gas from a companion Wolf-Rayet star lower right. Aurore Simonnet/Sonoma State University/NASA.)