STRANGE BUT TRUE- Mirages: Nessie, mermaids creations of light

DRAWING BY DEBORAH DERR McCLINTOCK

Q. How did sightings of the Loch Ness monster (Nessie) go the way of old sightings of mermaids and mermen? –C. Shepherd

A. Likely, all were mirages, with light rays refracted from their normal straight path by layers of air of varying temperatures (same as the common highway "oasis mirage"), says Jearl Walker in The Flying Circus of Physics. Under the right conditions, a log floating in water may seem to extend upward like the neck of a monster and to oscillate as if swimming. Conditions are ideal for such a mirage when cold water cools the air just above it while sunlight warms the higher air. Then some of the light is refracted downward, but only slightly, so the viewer must be near the water level to intercept the light.

Nessie statistics support this theory: about 77 percent of sightings occurred from May to August, when the water warms more slowly than the air; about 84 percent took place when the water was fairly calm, enhancing mirage visibility; and many of the observations were made by people near the water level.

Mermaids and mermen were probably distorted images of walruses and whales as seen by medieval seamen near the water surface, says Walker. Mermen, huge monsters that rose out of the sea, had shoulders like men but were handless and narrow at the waist. Mermaids were similar but with heavy hair, webbed hands, tails. 

"These mirages disappear if the observers are too close to the animals or too high to see the refracted light," he says. "So, once ships with high decks came into use, reports of the mythical beings decreased."

Q. When does a "hair dresser" become a "hair addresser"? –A. Martin

A. When she or he gathers up clients' shorn locks and turns them over to forensic anthropologists and analytical chemists, who can actually determine the approximate geographic region where the hair comes from, says Sid Perkins in Science News magazine. 

The water we drink, with its varying chemical isotopes of hydrogen and carbon, leaves a record in our hair that can be used to trace where we've been living, thus facilitating identification of victims of crime or disaster or helping poke holes in the alibis of suspected criminals. Because most of the water people drink is of local origin, its chemical signature becomes integrated into hair, fingernails, body tissue. Even though consumption of bottled water is up, much of the H20 in our milk, soda, beer, and reconstituted juice is still likely derived locally.

So once a large-scale isotopic map is drawn up, regional hair origins can be pinpointed. Says one Queen's University Belfast chemist, this technique won't find the needle in the haystack, but it will locate the haystack.

Q. Gunslinger John Cash saw his face on a poster nailed to a tree: "Wanted, Dead or Alive, Reward –- Dollars," with a three-digit figure. Miffed, John drew his Colt and shot away the first number, in the hundreds column. He had just reduced the price on his head by five times. He shot again at another number, in the tens column, further reducing the reward by another five times. Nice shooting, he thought to himself, then spurred his horse and rode away. What was the initial three-digit figure? –M. Vos-Savant

A. You number-slingers know that two five-times reductions in sequence amounts to a 25-times reduction overall. Thus, if the sole remaining number were a 1, the original number would have been 25– not enough digits, say Jaime and Lea Poniachik in Hard-to-Solve Brainteasers. The same shortcoming rules out 2 or 3. Using 4, the initial reward would have to be 100, which wouldn't work either. For a 5, 25 x 5 = 125 as the original number. In this case, erasing 1 leaves 25, or 1/5th of 125; then erasing the 2 leaves 5, which is again 1/5th of 25. Bull's eye!

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Send Strange questions to brothers Bill and Rich at [email protected].

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