Is There Vegetation on Mars?

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Science  14 May 1965:
Vol. 148, Issue 3672, pp. 946-947
DOI: 10.1126/science.148.3672.946


At least some of the changes in the color of Mars at different seasons are caused by color centers produced by electromagnetic and corpuscular solar radiation in solids on the surface. Calculated radiation flux, at appropriate energies and known temperature variation, could account for seasonal formation of color centers and bleaching if a simple trap model is assumed. In certain kinds of rhyolite (SiO2, NaAlSi3O8), which has been suggested as one of the possible constituents of the martian surface, color centers can be produced. No color centers are expected in limonite, Fe2O3 · 3H2O, the other likely constituent.