STRANGE BUT TRUE-
<img src="/images/issues/2006/0505/strange0505.gif"> <BR> DRAWING BY DEBORAH DERR McCLINTOCK
<p>Q. My visiting aunt became concerned that the kids on the swingset were going too high and might swing all the way around... like she did as a kid. We don't believe her story. She insists she did a complete 360 around the top bar. Would it be possible for a kid to gain the momentum to do that? –R. L. Stevenson</p>
<p>A. The centripetal force would need to be at least equal to gravity to keep some tension in the chains at the top, which for chains 2 meters long would require the child to go at 4.4 meters/second at the top– not too fast, says Yale University mechanical engineering professor David LaVan. However, this would mean higher velocity at the bottom of the arc, which works out to be about 10 meters/second (22 mph)– or about the speed of an Olympic sprinter. So: conceivable but unlikely.
The real deal-breaker is that she would be subjected to quite high centripetal forces– about 6 G's if going fast enough to make it all the way around. An aircraft pilot will black out when exposed to 4-5 G's. So, unless the person relaying the story had both 1) a catapult to propel her at 10 meters/second and 2) a NASA issued anti-gravity suit to prevent blackouts, "I would conclude that it is not something that really happened."
Quite possibly she reached a dizzying height, allows LaVan, lost her grip and fell off the swing backwards, making it seem like she went all the way around.
Q. Using every number from 1-16, construct a 4-by-4 "magic square" where all rows add up to 34 horizontally, vertically and diagonally. BTW, a famous artist depicted this particular magic square in a 1514 etching. –Sudoku
A. The matrix of 16-3-2-13 (top), 5-10-11-8, 9-6-7-12, 4-15-14-1 (bottom) appears in the upper right-hand corner of Albrecht Durer's etching "Melancholia I," where a melancholy thinker sits lost in thought amid a jumble of scientific objects, says Clifford A. Pickover in Wonders of Numbers."
Fascinatingly, the two central numbers of the bottom row read 1514, the year Durer did the etching. In addition to rows and diagonals, the four corner numbers and the four central numbers sum to 34. Rounding out the marvels here, even the sum of each of the four quadrants is 34 (e.g., 16 + 3 + 5 + 10 = 34), making it a "gnomon magic square," notes Mathworld.wolfram.com.
Q. Should a risk of 1 on the Torino scale cause us Earthlings the night sweats? However you answer, you might want to jot down 2029 as one of those pay-attention dates. –Mr. Spock
A. Torino is a sort of Richter scale for cosmic collisions, quantifying the risk of our being hit by an asteroid, with 0 being completely harmless and 10 a certain collision with possible global catastrophe, says New Scientist magazine.
Which brings us to 2029 and asteroid Apophis, 300-400 meters across, enough to take out a large city. This object was spotted in 2004, with NASA giving it a scary 4 on the Torino scale (greater than 1 chance in 50 of hitting Earth). Recalculations since suggest it will be a near miss instead at about 25,000 km from Earth's surface. But this close call will likely change Apophis' course, maybe tugging it to swing back around for a possible Earth hit in 2036, rating a 1 on the Torino scale.
One problem is scientists don't know enough about asteroids. Are they mostly solid, riddled with voids, or made of loose rubble? If we try to blow one up Hollywood-style, what happens? Maybe it would be better to send a probe to spray paint it white, causing greater force from solar radiation to gently push it off course, suggests the magazine.
"The 2029 approach is the closest a moderately large asteroid is likely to come during the next century," says Harvard astronomer Brian Marsden, "and regarding the possible hit in 2036, most likely we'll know by 2013 that this one too will be a clear miss."
Q. If alcohol can turn a man into a beast, what does it do to the beasts? –J. Daniels
A. Insects feeding on wine grapes in vineyards can become intoxicated on the fermentations, reports Ronald K. Siegel in Intoxication: Life in Pursuit of Artificial Paradise.
* Bumblebees, hornets and wasps will lose their coordination and become temporarily grounded after ingesting fermented fruits.
* In earlier times, illegal stills were sometimes traced by the trail of tipsy livestock that had sniffed out the mash.
* African villagers have been known to rid themselves of rodents by leaving out bowls of milk and beer, then rounding up the woozy pests in the morning.
* Parrots are said to become more talkative after eating fermented fruits or sipping alcoholic beverages. "The birds stop talking and drinking only after they fall over," says Siegel. One dealer in rare birds overdosed his parrots on tequila to quiet them for smuggling across the Mexican border.
* Herd-feeding elephants, afraid they won't get their fair share of fermented fruit, will at times gorge themselves into swaying inebriation.
* One dog that lived near a brewery got to where it would often drink beer instead of eating.
* If an experimental "bar" is opened for monkeys on a 24-hour basis, they'll go into binge and abstinence cycles, much like addicted people.
Send Strange questions to brothers Bill and Rich at email@example.com.