Across Olympus Mons and three other giant Martian volcanoes, seasonal morning frost only about 0.01 millimetres thick disappears within hours of sunrise—yet collectively, approximately 150,000 tonnes

The feature image contains the discovery in miniature. In an early-morning view of Ceraunius Tholus, pale blue material covers part of the volcano’s summit hollow. In a later image of the same terrain, the coating has disappeared. Blue is not the fro... [10242 chars]