But given their talent for consumption, why don't black holes just keep expanding and expanding and simply swallow the Universe? In 2018, one of the world's top physicists came up with a dazzling explanation.
The researcher behind this explanation is none other than Stanford University physicist Leonard Susskind, also known as one of the fathers of string theory.
He gave his two cents on the paradox in a series of papers, which basically suggest that black holes expand by increasing in complexity inwardly – a feature we just don't see connected while watching from afar.
Weirder still, this hypothesis might have a parallel in the expansion of our own Universe, which also seems to be growing in a counterintuitive way.
"I think it's a very, very interesting question whether the cosmological growth of space is connected to the growth of some kind of complexity," Susskind was quoted in The Atlantic.
"And whether the cosmic clock, the evolution of the Universe, is connected with the evolution of complexity. There, I don't know the answer."