Verrucchi now suspects this is key to how time works. The arrow of time, she says, might simply be a record of what has been measured. Like flicking through a cosmic flipbook, we reveal new pages by interacting with the elements of reality – or “making measurements” as a physicist might put it. The act of simply being in the world collapses our quantum reality into a definite state, leaving an irreversible record behind.

And if clocks are physical systems that record measurements – and we are, too – then perhaps we aren’t just observers of time, says Verrucchi, but participants in its making: “You create time when you ask what time it is.”