Given that our first direct detections confirming the existence of black holes only took place in this century, humanity can be forgiven for not knowing a few things about these mysterious cosmic objects. We don't even know everything we don't know – a fact that's been made evident in a new discovery. While running equations for quantum gravity corrections for the entropy of a black hole, a pair of physicists found that black holes exert pressure on the space around them. Not much pressure, to be sure – but it's a finding that's fascinatingly consistent with Stephen Hawking's prediction that...