The Obliquity of Mars SpaceDaily

In my previous report, I described one theory (the so-called “salty soda fountain” concept) being used to explain the startling new photos by Mars Global Surveyor which seem to show signs of recent eruptions of groundwater out of near-surface strata on Mars — and in the coldest regions of Mars, at moderate to polar latitudes and usually on slopes facing away from the Sun. But there are rival theories — in which the “springs” aren’t springs at all. In one of these (currently favored by Dr. Jeffrey Kargel of the U.S. Geological Survey in Flagstaff, Arizona), the gullies are indeed due to water runoff, but from something even more spectacular in its implications than subsurface springs — namely, the intermittent accumulation and melting of thick layers of surface ice on Mars.