Science Friday

The Spirit and Opportunity rovers press on in their lonely journeys across the martian landscape, according to the New York Times -- and they continue to find "signs that Mars was once awash in water." The biggest news here seems to be the discovery by Spirit of chemically altered rocks at Gusev -- significant because, until now, Spirit has found relatively little evidence of water there. Opportunity, meanwhile, has stumbled across some appealingly mysterious-sounding, lumpy rocks unlike anything it's seen until now. Another nice write-up of this on Space.com. The little buggers just keep on chooglin' -- they've already more than doubled their intended mission lifetimes.

Nice little paper published online in Science today; it's written up on New Scientist. The paper deals with the Pirahã, a hunter-gatherer tribe in Brazil whose language has a "one, two, many" counting system -- that is, they don't have words for numbers greater than two. The big surprise of the study: for adult speakers of this language, the system seems to cripple their performance on simple numerical tasks (like duplicating a line of batteries) that involve quantities greater than three. The result adds weight to the notion of "linguistic determinism" -- the very controversial idea that, in essense, what you can say determines what you can think. You need to subscribe to Science (or purchase the paper individually) to see the full text, but the abstract is available free if you register.

A few other notables:

--A senior epidemiologist at the U.S. FDA concluded in 2003 that antidepressants are too risky to be prescribed for children, based on a welter of studies that suggest that kids given antidepressants are twice as likely to commit suicide as those given placebos. The FDA brass, however, kept his findings under wraps. Now a second lab has confirmed his findings, and the FDA brass has some explaining to do. (New York Times)

--Occupational and Environmental Medicine releases a study (from France) suggesting that children who live near gas stations are four times as likely as controls to develop acute leukemia. (New Scientist)

--An upcoming paper in Physical Review Letters argues that for tiny objects such as carbon nanotubes -- touted as the building blocks for a range of minature devices that will stoke a nanotechnology revolution -- the concept of temperature is meaningless. Says Peter Atkins of Oxford University: "If you're down to a scale where temperature is not relevant, the fluctuations in physical properties of that system could be unpredictable, and that is potentially bad for any device." (news@nature.com)