Clark R. Chapman, in Asfrononzy
'Mercu~'~
(Nov. 19881, 1027 N. 7th St., Milwaukee, Wisc. 53233.

More than a decade after America's un- manned Mariner 10 flew near the planet Mercury during 1974-75, scientists have fi-nally digested all of the data from the flight. And they are starting to ask some big questions, reports Chapman, of Tuc- son's Planetary Science Institute.
Located about midway between the Earth and the Sun, Mercury is a "truly bi- zarre" planet. Its rock cmst is unusually t...