Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site sbcs.UUCP Path: utzoo!watmath!clyde!bonnie!akgua!sdcsvax!sdcrdcf!hplabs!hao!seismo!cmcl2!philabs!sbcs!debray From: debray@sbcs.UUCP (Saumya Debray) Newsgroups: net.cooks,net.flame Subject: dark skins near equator Message-ID: <111@sbcs.UUCP> Date: Fri, 30-Nov-84 14:30:09 EST Article-I.D.: sbcs.111 Posted: Fri Nov 30 14:30:09 1984 Date-Received: Tue, 4-Dec-84 08:23:05 EST References: <2559@dartvax.UUCP> <642@watdcsu.UUCP> <1245@utah-gr.UUCP> <2804@ucbcad.UUCP> Organization: Computer Science Dept, SUNY@Stony Brook Lines: 17 Xref: watmath net.cooks:3189 net.flame:7064 > What I've always wondered is why the closer to the equator people live, the > darker their skin tends to be. It seems that in the interests of > maintainting a reasonable body temperature, it should be just the opposite. > Melanin (the dark pigment you refer to) blocks out ultraviolet radiation: because the amount of atmosphere sunlight has to travel through is lesser nearer the equator, less UV is absorbed by the atmosphere and more of it reaches the surface. -- Saumya Debray, SUNY at Stony Brook uucp: {cbosgd, decvax, ihnp4, mcvax, cmcl2}!philabs \ {amd, akgua, decwrl, utzoo}!allegra > !sbcs!debray {tektronix, metheus}!ogcvax / CSNet: debray@sbcs