Fields of sharp ice growing to almost 50 feet (15 m) tall could be scattered across the equatorial regions of Jupiter’s moon Europa, according to a new study published in the journal Nature Geoscience. Terrestrial penitentes from the southern end of the Chajnantor plain, Chile, in 2005; the view is broadly northwards; blades can be seen perpendicular to the viewing direction. Image credit: ESO. On Earth, the sublimation of massive ice deposits at...