Deposits on Mars May Be Large Ice Cap

An article posted today by National Geographic news discussed a possible ice cap at the equator of Mars. The materials were spotted at the equator, but they appear to contain a large amount of water that has only been seen on the Red Planet's poles. The materials were found using a new high-resolution radar camera which shows similarities between the properties of deposits on an area called Medusae Fossae. The observed properties may also mean that the Martian equator is rich in ice. Thomas Watters of the Smithsonian Institution's National Air and Space Museum has examined the Martian surface with his team of scientists. They have been using an instrument called MARSIS, which is aboard the European Space Agency's Mars Express orbiter. The nature of the deposits has been a geologic mystery for decades. The radar observations have deposits more than 1.4 miles thick in places. The data also showed that the deposits are highly porous, meaning that they could be pure ice protected by a blanket of sediments. However, Watters and his team believe that volcanic ash or wind-blown deposits could be sources of materials porous enough to look like ice in the images. On Earth volcanic pumice can be up to 90 percent porous when it's first deposited, but gravity soon forces it to collapse on itself, thus decreasing its porosity. Since gravity is much lower on Mars, highly porous deposits may retain their properties longer. The question is how thick of a deposit could be sustained and have such low porosity. The team now needs to see if there is a plausible alternative to ice.