Misfit meteorites that don’t fit neatly into known categories could be relics from a lost Mercury-like world that was destroyed early in the history of the solar system.

Most asteroids that fall to Earth as meteorites can be grouped together and have common origins, with many derived from larger asteroids, the moon or Mars. But around 0.2 per cent of meteorites are outliers, resisting any neat categorisation.

Now, Jennifer Mitchell at…