Health & Science

A new search for signs of life on Mars

NASA has launched its most ambitious mission yet to probe Mars for evidence of life. Curiosity, a 1-ton rover powered by a small nuclear reactor, lifted off aboard a rocket last week with a full array of instruments to study the Red Planet’s geology, chemistry, and possible biology. Once the 354-million-mile journey is completed, next August, Curiosity’s entry vehicle will descend to within 66 feet of the Martian surface, then lower the rover down on cables for a soft landing near the mineral-rich Gale Crater. Curiosity, about the size of a Mini Cooper, will spend at least two years exploring the Martian landscape. One goal is to search for evidence that our nearest neighbor once hosted life—or even that it still does. “Unequivocally, the conditions for the emergence of life were present on Mars,” NASA senior scientist Michael J. Mumma tells The New York Times. Curiosity is not equipped to detect life directly, but it carries an instrument that detects organic molecules—including methane, a gas generated on Earth by microbes and other living organisms. Some scientists say they’ve already detected methane in the Martian atmosphere, and hope Curiosity can find out where it’s coming from.

Why we need orthodontists

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Mankind’s embrace of agriculture may be the reason so many of us have poorly aligned teeth. Anthropologist Noreen von Cramon-Taubadel, at the U.K.’s University of Kent, analyzed human skulls from 11 cultures around the world. Those that belonged to farm-fed societies, she found, had short jaws filled with crowded, overlapping teeth, whereas members of groups that hunted and foraged had longer, roomier mandibles. The difference, she says, is diet, not genetics. “Presumably, the children growing up in these different situations have different chewing behavior,” Von Cramon-Taubadel tells DiscoveryNews​.com. People living in agricultural societies are more likely to eat starchy, cooked meals of rice, corn, and bread that require only light chewing—and previous studies have shown that jawbones grow shorter when they lack exercise. Hunter-gatherers are more likely to consume a chewier diet of wild game, nuts, and raw vegetables, and thus give their jaws more of a workout every day. “Our behavior can have such a dramatic effect on our biology,” Von Cramon-Taubadel says. Children who chew tougher foods, she says, tend to have straighter teeth when they grow up.

Data right before your eyes

Who needs smartphones? We may soon be able to call up emails and other data on Internet-enabled contact lenses. Researchers at the University of Washington have fit an antenna, a miniature circuit, and a tiny LED into a lens designed for rabbits. The light, powered by remote control, glowed without causing any harm to the animals, moving us one big step closer to the day when “we’ll have full-fledged streaming in your contact lenses,” electrical engineer Babak Amir Parviz tells DiscoveryNews​.com. Researchers still need to devise a less-cumbersome way to power the lenses, and to figure out how to make them transmit more data than a single pixel. But they have already succeeded in designing contacts with a super-short focal length to sharpen the light display, since an object so close to the eyeball would ordinarily appear shadowy and out of focus. Smart lenses could soon be used to monitor medical conditions like glaucoma, and within the next decade, they may also be able to display text—such as driving directions—directly over objects in our field of view, or make us part of advanced video games. A mere five years ago, projecting images onto contacts “was something like science fiction,” says Arnaud Bertsch, a microsystems researcher in Switzerland. “Now it’s real.”

Just 4.74 degrees of separation

Popular wisdom says that only “six degrees of separation” stand between you and anyone else. Now, a new Facebook study says we’re getting more closely linked than that. University of Milan researchers analyzed the “friend” links among Facebook’s 721 million members. On average, only 4.74 hops from friend to friend were needed to bring any two members together, as opposed to 5.28 three years ago. That means “when considering even the most distant Facebook user in the Siberian tundra or the Peruvian rain forest, a friend of your friend probably knows a friend of their friend,” Facebook says. The data highlight how useful social-networking sites can be to researchers studying the behavior of extremely large groups of people. But the new networks created by social media may not be as strong as friendships made the old-fashioned way. Facebook, Cornell computer scientist Jon Kleinberg tells The New York Times, allows us to be “close, in a sense, to people who don’t necessarily like us, sympathize with us, or have anything in common with us.”