Science: Weather Report from Mars

Mars has an atmosphere; therefore it must have weather. Starting with this thesis—as thin as the Martian atmosphere itself—Seymour L. Hess of Lowell Observatory, Flagstaff, Ariz, set out to chart Martian weather. He reports his findings in the current Sky and Telescope.

Even through a large telescope, Mars looks like a small reddish disc doing a slightly hysterical dance. But delicate instruments can measure with fair accuracy on its barren surface the temperature of spots as small as 400 miles wide. Since differences of temperature (which make an atmosphere circulate) are the basic cause of weather, measurements of temperature can be translated...