A tiny sample of the Moon locked away for more than 50 years turns out to have been hiding an astronomical secret.

In specks of troilite dust collected by Apollo 17 in 1972, scientists have found material that may be as old – or even older – than the Moon itself, a 4.5-billion-year-old relic of the early Solar System.

“My first thought was, ‘Holy shmolies, that can’t be right,’” says planetary scientist James Dottin of Brown University in the US.