Mars’ Expanding Shadow in Utopia Planitia Baffles Scientists After 50 Years

A dark patch in Mars’ Utopia Planitia, made of ash and volcanic rocks, has slowly expanded since it was first photographed by Viking 2 in 1976. ESA’s Mars Express captured new images in 2024 showing the shadow creeping southward by roughly 320 km (about 6.5 km per year). Scientists think Martian winds likely move the ash or blow away dust covering it, but the exact cause is still unknown.