As the United Kingdom peers into a metaphorical black hole of its own making, one of its most accomplished sons has been honoured with the minting of a 50 pence coin (pictured), featuring artist Edwina Ellis’s impression of a black hole.

Credit: Royal Mint

On the occasion of his 60th birthday, Stephen Hawking described how he came up with Hawking radiation1 — the stunning revelation that black holes are not entirely black. Characterizing it as a ‘warm-up exercise’ for his attempt to unite general relativity with quantum theory, Hawking expressed surprise that his calculation predicted a black-hole emission. His fondness for the discovery was manifest in his request that the formula relating the entropy of a black hole to the area of its event horizon be etched into his tombstone2. The new coin will see this celebrated equation circulated widely.

Hawking is only the third Briton to be honoured with a coin within a year of death, his predecessors on that count being Winston Churchill and the Queen Mother. He also follows Isaac Newton, whose legacy was celebrated with a coin in 2017, and Charles Darwin, who was similarly commemorated in 2009. Hawking’s coin is the first in a new series celebrating innovation in British science.

For reasons unknown, the tombstone for Hawking at Westminster Abbey features an equation expressing the temperature of Hawking radiation rather than the black hole entropy relation that much of the science world expected. Perhaps the minting of the new coin will appease Hawking’s ghost.