New evidence from the first probe to orbit Mercury is building support for the idea that the
tiny planet may be harboring water ice in some of its most extreme terrain. Certain areas of Mercury’s poles were previously found to be bright in radio waves detected by radar measurements from the Arecibo Observatory in Puerto Rico. Now, the Messenger spacecraft has found that those same bright radar spots appear to be in permanent shadow, according to camera views from the probe’s Mercury Dual Imaging System (MDIS). As said Nancy Chabot, an instrument scientist for MDIS at the Johns Hopkins University Applied Physics Laboratory they have never had the imagery available before to see the surface where these radar-bright features are located. MDIS images show that all the radar-bright features near Mercury’s south pole are located in areas of permanent shadow, and near Mercury’s north pole such deposits are also seen only in shadowed regions, results consistent with the water-ice hypothesis. The Messenger probe’s Mercury findings are not conclusive, though. According to researchers those bright spots could represent some other substance. Plus, some pieces of evidence don’t fit together perfectly. However the scientists have a better picture of these intriguing areas now than ever before, and they hope to solve the mystery with further study in the future. If there is water ice on Mercury, the planet will not be alone. Earth’s moon also seems to have water ice at its poles. Evidence for frozen water has also been found on Mars and many asteroids in the solar system.