SCIENTIFIC AMERICAN SUPPLEMENT Nn 2246 43 "[11<'(' the re<:uverable re<. 'Urds lJegall in the garth's crust. Pussibly we may assume a stabilizing effect of tile E:arth's atmusphere that might allow in the surfal'e temperature uf the Sun a range uf a few hundred degrees withuut dire consequences for terrestrial life. A difference of even a single spectral type, however, would correspond to a change of several hundred per <:eht. In light·emission, and that appears to be wholly out of (IUestion.