YOU’D think it would be easy to tell the difference between something fluffy and dusty, or cold and wet. Not so, if you’re looking at strange mounds on Mars.
For decades, scientists have puzzled over weird geological structures at Mars’s equator called the Medusa Fossae Formation. Now radar observations seem to indicate that they contain huge glacier-like deposits of frozen water 2.5 kilometres below the surface (Science, DOI: 10.1126/science.1148112).
Thomas Watters of the National Air and Space Museum in Washington DC led a team that probed the formation with ground-penetrating radar aboard the European Space Agency’s Mars Express spacecraft.…
