By Elizabeth Royte
Why do dogs roll in really gross stuff?
— Burt Ailes, Waterford, Virginia
The dog research establishment is divided on the purpose of this endearing trait. Whatever it is, it appears to be a lupine thing. Just like dogs, wolves are known to slap on such heady fragrances as urine, vomit, feces, and rotting carcasses. Some experts suggest that dogs and wolves do this to be more "at one" with their territory. Maybe our annoying
canids are trying to mask their own scent for hunting, or trying to repel insects. Maybe they're trying to leave their own chemical Kilroy in the mess for the benefit of other sniffers. Another theory suggests, oddly enough, that it's a social trait."Studies show that dogs are bringing back information about their turf," says Pat Goodmann, an Indiana wolf
expert who actually wrote her master's thesis on this subject. "They're telling the pack what they've found, helping to develop mental maps of the area." Which is all well and good, except that with domesticated dogs, "the pack" is you.
But there's a more obvious explanation, notes Mark Derr, a well-known Miami-based canine authority: "Dogs do it because they enjoy the smell. They're like those people who can't walk past the perfume counter without spraying the stuff all over themselves."
Is there really such a thing as "lake turnover"?
— Franklin Genovese, Dallas, Texas
Along with the more overt signs of fall's arrival — geese winging south, pumpkins swelling on the vine, hordes of Winnebagos spoiling the Vermont foliage — comes an almost imperceptible telltale of the season: lake turnover, or "inversion," as it's known among snooty limnologists. Almost all bodies of fresh water and some saline lakes turn
over this time of year. Here's how it works: Ordinarily lakes are stratified into well-defined thermal bands; the deeper you go, the more frigid the waters. But as the mercury drops in the fall, the lake's warmer, lighter, more oxygenated surface water cools and settles. Aided by the wind, the different layers get mixed up, so that the lake becomes nearly
uniform in temperature and oxygen content from top to bottom. In this confusing world, fish often stop feeding (turnover season is renowned as the time when anglers reacquaint themselves with their families). In extreme cases, turnover can churn up enough oxygen-deficient water to cause dramatic fish kills. Some lakes develop a murky green hue and an odd
stench, the smell of rotting organic matter that's been stirred up. But it's all fleeting. Come winter, ice forms on the surface, the wind becomes a nonplayer, and stratification again sets up shop.
What causes the "man in the Moon" effect?
— Rebecca Roth, Calgary, Alberta
Most astronomers pooh-pooh the phenomenon of the man in the Moon. "I've never seen it," says Frank Summers of New York's Hayden Planetarium, "and I don't know anyone who has." All the same, people have reported seeing things in the Moon for millennia. The Egyptians thought the Moon was a dog-headed ape, while in ancient China the Moon was widely viewed
as a hare. In the nineteenth century, the man in the Moon shared equal billing with the crab in the Moon, the lady in the Moon, the girl reading in the Moon, and the donkey in the Moon. We see what we want to see up there, but our imagination is aided by the Moon's multicolored topography, particularly the contrast between its gray, powdery soils and the
swaths of dark lava that form the "lunar seas." It's these basalt seas that are said to form the man's "eyes" and "mouth." But don't tell that to learned astronomers. "The man in the Moon is just an expression," says Noreen Grice of Boston's Museum of Science. "No, it's an illusion. No, I know: It's a perception. That's what it is."
|November's leonid meteor shower, which will peak just before dawn on the 17th, may be overpowered by the Moon, full just three days earlier. But the Leonids aren't the only points of interest this month. On the evening of the sixth, Venus will be 27 degrees to the south of the celestial equator — it
won't pass this far south again until 2005. On the 11th, the Moon will be very near Saturn, with an occultation of the ringed planet occurring in the tropical part of the Americas and throughout Europe. In general, dusk will find Venus extremely bright and low in the southwest, Jupiter bright in the south, and Saturn gaining altitude in the
east-southeast. Mars can be found low in the southwest; Mercury, very low in the west-southwest. — David N. Schramm
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