Random Samples

Science  27 Jun 2008:
Vol. 320, Issue 5884, pp. 1701
1. PI FROM THE SKY?

A math lesson from outer space, or a hoax delivered by cheeky mathematicians with too much time on their hands? It turns out a crop circle that first appeared 12 years ago in Wiltshire, England, actually codes for pi, the fundamental mathematical constant associated with circles. While perusing photos on a Web site devoted to crop circles, retired astrophysicist Michael Reed in South Carolina noticed that the curves in the 76-meter-wide pattern correspond to a 10-digit approximation of pi, 3.141592654. When the circle is sliced into 10 equal parts, each concentric arc, reading from the middle of the figure outward, represents a digit by the number of wedges it crosses. The decimal point even appears as a dot near the center after the first arc. Mathematician Colin Adams of Williams College in Williamstown, Massachusetts, observes that it would make sense for a jokester to use this constant: “If aliens are out there, then pi would be important to them. If I were someone set on making something look alien, this is the number I would pick.”

2. PARACELSUS, EAT YOUR HEART OUT

Alchemists never turned lead into gold, but a team of Mexican physicists has transformed tequila into diamond. For decades, researchers have made diamond films by exposing a surface to a hot vapor containing carbon, hydrogen, and oxygen. Usually they begin by vaporizing mixtures such as ethanol and water. But Victor Castaño, Javier Morales, and Miguel Apátiga of the National Autonomous University of Mexico in Querétaro have found that tequila straight out of the bottle does the trick. White tequila, produced by fermenting the flesh of the blue agave plant, has the right concentrations of hydrogen and oxygen to guide the carbon in it to form diamond instead of graphite or carbon black, Castaño says. And impurities in the liquor help nucleate the crystallites. The team reports its work on the arXiv preprint server (http://www.arxiv.org/).

Using booze to make diamond isn't new. In the 1980s, Japanese scientists reportedly used sake, Russians used vodka, and Americans used whiskey. Paul May, a physical chemist at the University of Bristol, U.K., says his group even moved from the bar to the grill: “We once grew diamond using as a source of carbon the grease from a leftover lamb kebab” that was exposed to a hydrogen plasma, he says. After all, there are better uses for the liquor.

3. HOMER AND THE ECLIPSE

Hints of a solar eclipse at the climax of Homer's epic the Odyssey may be based on fact, a biophysicist and an amateur astronomer say.

The poem describes the adventures of Odysseus on his journey home to Ithaca from the Trojan War. Intrigued by astronomical references in the text, Constantino Baikouzis and Marcelo Magnasco of New York City's Rockefeller University constructed a chronology of the final 40-day voyage that culminates when Odysseus returns home and slays his wife Penelope's suitors. Before the fight, a seer mentions the obliteration of the sun and sudden darkness—a line some scholars believe describes an eclipse.

The researchers analyzed four astronomical references to Mercury, Venus, the new moon, and the appearance of two constellations—the Pleiades and Boötes—that are rarely seen together, they report online this week in the Proceedings of the National Academy of Sciences. Using powerful new astronomy software, Magnasco says, “we matched the pattern in which they happen in the Odyssey” and found that it occurs only once every 2000 years. The computations placed Odysseus's return on 16 April 1178 B.C.E. That's the exact date astronomers have identified for a total solar eclipse that would have been visible from the Ionian islands.

Magnasco says the analysis suggests that there may be more factual truth in the Odyssey than some scholars have believed and that Homeric Greeks may have known about movements of the planets some 400 years before Plato wrote about them.

4. GET ONLINE, LITTLE DOGIES

When roboticist Daniela Rus visited an Australian cattle ranch a few years ago, she saw an opportunity to innovate. The company used helicopters to herd 24,000 cows across rangeland the size of Vermont, but the biggest headache was maintaining the fences. Rus, now at the Massachusetts Institute of Technology in Cambridge, has created a “smart collar” to keep cows from straying. “It's a next step in cow manipulation,” she says.

The bovines wear GPS-equipped headsets that make noises to scare them when they try to leave a designated area. After trying sounds such as roaring lions and crashing cars, the researchers found that barking dogs usually do the trick. If a cow ignores the yapping, its solar-powered unit delivers a mild electric shock. Rus has since teamed up with Dean Anderson, an animal scientist with the U.S. Department of Agriculture in Las Cruces, New Mexico, who had been working on the same idea. (His warning noises included cowboy songs and pickup truck engines.) This August, the pair will outfit 10 cows with headsets programmed to herd them from pasture back to their barns.

The collars can also be used to collect data on animal movements and other behaviors. “You can log in to specific cows,” Rus says. The pair plan to add webcams, allowing e-cowboys to watch for trouble, and possibly heart-rate monitors to monitor animal stress levels.