Has Phoenix uncovered ice or salt?
Is the white stuff in the Martian soil ice or salt? That's the question bedeviling scientists in the three weeks since the Phoenix lander began digging into Mars' north pole region to study whether the arctic could be habitable. Shallow trenches excavated by the lander's backhoe-like robotic arm have turned up specks and at times even stripes of mysterious white material mixed in with the clumpy, reddish dirt.