With average surface temperatures around -230°C, Pluto doesn’t seem like it would resemble a beach, but at the base of its icy mountains is a field of towering dunes.

At the edge of a mountain range called Al-Idrisi Montes, a belt of ridges spans 75 kilometres atop a glacier of nitrogen ice . Matt Telfer at the University of Plymouth in the UK and his colleagues examined data from NASA’s New Horizons spacecraft to determine whether these ridges could be dunes …