This is going to take a while to explain, so bear with me. My kid is a fan of the Age of Empires series of computer games, which give you a bird’s-eye view of the landscape on which your armies cavort. You can see an amazing amount of detail, but a while back I noticed something I found comical: whenever you come across an A-of-E island, you see waves crashing on the beach on all sides. Damn computer geeks who wrote this need to get out more, I thought–don’t they know waves are driven by the wind, and the wind can’t blow in all directions at once? I felt smug till we visited the Hawaiian island of Kauai over Christmas. Our cottage was on the south side of the island–we were lulled to sleep by the waves crashing on the beach. We visited the famous Na Pali coast on the north side of the island, and were impressed but a little puzzled (I was, anyway) by the massive waves crashing on the beach. Finally we took a helicopter tour, and you know what? On every side of the island there were waves crashing on the beach. I’m stumped. OK, the waves on the north were bigger than those on the south–supposedly this is due to winter storms. But shouldn’t the waters on the lee side of an island be calm? –Alden S., Chicago
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You get the picture. The towel and the pole represent a wave striking an island. Initially the wave is heading uniformly south, but as it brushes the sloping sea bottom surrounding the island, friction causes it to slow and bend (or refract, I guess we should say) and in effect wrap around the obstructing landform. The practical result is that though the waves strike most forcefully on the north side of the island, they crash on the beach even on the south side, in all cases (barring topographical eccentricities) looking essentially like they’re coming from straight offshore. Luckily for us traditionalists, this life-imitates-Age-of-Empires thing goes only so far. Who really wants human reproduction to be a matter of simply selecting a town center and pressing V?
Did atheists first come from Athens? –Nighthawk5000, via e-mail
Art accompanying story in printed newspaper (not available in this archive): illustration/Slug Signorino.
