They are impressive, mysterious structures that loom out of deserts on the Earth and are also found on Mars and on Saturn’s biggest moon, Titan.
Experts from universities including Aberystwyth in Wales have now pinpointed the age of a star dune in a remote area of Morocco and uncovered details about its formation and how it moves across the desert.
Prof Geoff Duller of the department of geography and earth sciences at Aberystwyth said: “They are extraordinary things, one of the natural wonders of the world. From the ground they look like pyramids but from the air you see a peak and radiating off it in three or four directions these arms that make them look like stars.”