UK Put a Black Hole on a 50p Coin to Honor Stephen Hawking, And It Looks Stunning

The U.K. Royal Mint has issued a 50-pence coin commemorating the late physicist Stephen Hawking, who died nearly one year ago at age 76.

The collector's coin, which is selling online for $10 pounds, depicts Stephen Hawking's name surrounded by lines that form concentric circles representing a black hole. Written above his name on the coin is the Bekenstein-Hawking formula, which describes black-hole entropy, and shows that the surface area of a black hole expands as it consumes more matter. It also supports the idea that black holes aren't completely black.

"This is such a lovely way to commemorate him and his legacy," said Lucy Hawking, Stephen Hawking's daughter known for her work as a children's novelist and science educator. "It's a 2D surface that seems to have a 3D image on it. It's as though you could fall into the black hole."

Coin designer Edwina Ellis said she "wanted to fit a big black hole on the tiny coin and wish he was still here chortling at the thought."

"The initial inspiration was actually Stephen Hawking's description of black holes," Ellis said. "It was only afterwards I realize I hadn't used anybody else's graphic imagery because he gave it to me."

Amid swirling lines angled to inspire thoughts of space curving around an event horizon is Hawking's name below the formula S = kc^3 A / 4ℏG.

Not only is it just the thing to remind you of one of the greatest minds in modern science, it's handy just in case you forget how to calculate the thermodynamic entropy of a Schwarzschild black hole of a given mass.

Known as the Bekenstein-Hawking formula – an honour shared with the theoretical physicist Jacob Bekenstein – its derivation was a significant step forward in efforts to make the weird properties of black holes fit with existing laws on energy.

In simple terms, it links the amount of disorder contained by a black hole with a physical feature of the hole itself: its area. Taken further, it means adding material to a black hole makes its surface expand.

This also implies a way to make black holes less black through the emission of a weird kind of radiation, a finding that Hawking proudly counted as one of his landmark contributions to science.

Even if you don't find yourself needing the Bekenstein-Hawking formula while buying your morning coffee (although we suggest not spending a collector's item to do that), the coin is a beautiful reminder of a man who not only advanced physics, but helped make many mind-blowing aspects of the Universe accessible to the non-expert.

The design certainly has his daughter Lucy's approval.