The Bad Astronomer writes: "Just in time for the holiday season, the NASA space probe MESSENGER appears to have all but confirmed the existence of ice at Mercury's north pole. Ice has long been suspected to be hiding in permanently shadowed areas in deep craters at the planet's pole, but new data show several converging lines of evidence (thermal and visible light mapping, radar, neutron emission) that as much as a trillion tons of ice may be buried just centimeters deep under the surface. Scientists also see evidence of organic (carbon-based) molecules as well. That's not life, but it's more of an indication that volatile compounds can exist on the solar system's innermost planet."
We warn the reader in advance that the proof presented here depends on a
clever but highly unmotivated trick.
-- Howard Anton, "Elementary Linear Algebra"