Q) Is there a magnetic pull in space? If so, in what direction would a compass point?
Levi Strong, Caldwell, Kansas
A) DON'T BLAME space junk, but yes, there is magnetism in space. Magnetic fields, which are produced by the dynamo effect caused by spinning liquid iron, such as the core of a planet, are found throughout the universe. "The earth's magnetic field extends to a specific boundary called the magnetosphere," explains Jeffrey Love, a geomagnetism scientist with the U.S. Geological Survey. Once you leave our magnetic field, you come under the sway of the sun's magnetic force, called the Interplanetary Magnetic Field. But here your compass might be off by as many as 40 degrees, since the solar windstreams of ionized gas particlesconstantly "blows" the sun's magnetic field in several directions. Unlike the straight lines produced by the earth's magnetic field, Love says, the sun's lines of force "resemble a tangled plate of spaghetti." As you moved out into interstellar space, you'd find several sources of magnetismthe spiral arms of the Milky Way, enormous clouds of dust and gas, black holes, supernovasany of which might influence a compass's reading. So when you bid on that spaceship of the future on eBay, make sure it has a guidance system of the future: A compass won't do you much good out thereand forget about a GPS.
Q) Why are there such individualized names for groups of animals: gaggles of geese, packs of wolves, herds of sheep, etc.?
Andy and Alisa Mallinger, Portland, Oregon
A) IF YOU'VE EVER taken up a sport and suddenly found your vocabulary becoming much larger (abseil, 'biner, belay...), then you may understand how these terms came into being. In the Middle Ages, the collective nouns given to animals were likewise part of the lingo of a sport: hunting. They were dubbed "terms of venery" (from the Old French word vener, meaning "to hunt"), and their use was tied to the Forest Laws, a set of guidelines written to protect the animals on the king's hunting lands. The first major reference to these words in literature appears in Thomas Malory's 1485 King Arthur classic Le Morte d'Arthur, in which Sir Tristram is said to know "all the good terms of venery and hunting... and of him we had all the terms of hawking, and which were beasts of chase and beasts of venery." In other words, Tristram knew a clowder from a murder, and therefore he was somebody. Some of the names are more generic (a gang of elk), others are anthropomorphic (a parliament of owls), and some are downright poetic (an exaltation of larks). While they make for funny dinner conversation now, in days of yore these words were taken very seriously. "Hunting animals and birds was a noble sport," says Allan Metcalf, an English professor at MacMurray College, in Jacksonville, Illinois, "and it was noble to know all of the various terms of the hunt."
Q) Why do cows have four teats? They only rarely give birth to twins, much less quads.
Sarah Kast, Minneapolis, Minnesota
A) YOU'RE RIGHT: Cows generally bear only one calf per pregnancy, so it does seem odd that they'd have so many teats. But according to Professor Walter Hurley of the University of Illinois, we're pretty sure that the cow's remote ancestors had more than one babymaybe many moreand that, like most animals, they've evolved toward fewer offspring. Fossil records show that millions of years ago, cows and pigs shared a common ancestor, an animal that looked more pig than cow. It probably had multiple offspring, like a pig, which has litters of 12 to 14, so it would have needed more teats to nurse them. It seems the modern cow retained those extra teats, which isn't a bad thing: Extra nipples means there will always be a supply of milk should one teat get infected and stop working. Interestingly, 50 percent of dairy calves are born with more than four teats; the mostly useless "supernumerary" nipples can occur even in humans.
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