... Behemoth black hole found in an unlikely place . ... How black holes change gear . Astronomers found that black holes do not necessarily come with two different engines, but that each black hole can run in two different regimes, like two gears of the same engine. ... We found that these two black holes could also 'change gear,' demonstrating that this is not an exceptional property of one peculiar black hole,т?? said Ratti. т??Our work suggests that changing gear might be common among black holes. ...