"The pin-drop moment when we realised that the mystery result in our equations was telling us that the black hole we were studying had a pressure – after months of grappling with it – was exhilarating," Kuipers said .

It's uncle...

"Our finding that Schwarzschild black holes have a pressure as well as a temperature is even more exciting given that it was a total surprise," said physicist and astronomer Xavier Calmet of the University of Sussex in the UK.

"If you consider black holes within only general relativity , one can show that they have a singularity in their centres where the laws of physics as we know them must break down.

"It is hoped that when quantum field theory is i...

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.

Not much pressure, to be sure – but it's a finding that's fascinatingly consistent with Stephen Hawking's prediction that black holes emit radiation and therefore not only have a temperature, but slowly shrink over time, in the absence of accretion.

When they made their discovery, Calmet and his University of Sussex colleague, physicist and astronomer Folkert Kuipers, were performing calculations using quantum field theory to try and probe the event horizon of a black hole.

Specifically, they were trying to understand the fluctuations...

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.