Phoenix Lander confirmed that ice is under the surface in the northern region of the planet Mars.
The Lander’s robotic arm started digging trenches into Martian soil after touching down near the planet’s north pole on May 25, revealing a white substance that scientists had said could be either salt or ice.
Phoenix flexed its arm again to enlarge a trench on June 15. It then took pictures of eight bright bits of material the size of dice inside the hole, which scientists dubbed Dodo-Goldilocks. When the Lander took new photographs of the trench four days later on Thursday, the material had vanished, settling the debate about whether it was salt or ice.
Scientists at the Jet Propulsion Laboratory in Pasadena, California concluded that the material was frozen water that evaporated when exposed to the sun. Salt would not have reacted that way, scientists said.