Number 55 (Story #3), November 7, 1991 by Phillip F. Schewe and Ben Stein MERCURY'S POLES MAY BE COVERED WITH ICE. Radar studies by Duane Muhleman and others at Caltech and JPL reveal a brightness indicative of water ice; the radar signals also resemble those from known ice deposits on Mars. Despite its broiling nearness to the Sun (Mercury's equatorial temperatures reach 800 degrees Fahrenheit), the planet's rotational axis is vertical, an orientation which leaves the poles cold enough to foster ice. (The New York Times, 7 November 1991.)