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12 December 2013 1:00 pm ,
Vol. 342 ,
Evolutionary biologists have long studied how the Mexican tetra, a drab fish that lives in rivers and creeks but has...
Victorian astronomers spent countless hours laboriously charting the positions of stars in the sky. Such sky mapping,...
In an ambitious project to study 1000 years of sickness and health, researchers are excavating the graveyard of the now...
Stefan Behnisch has won awards for designing science labs and other buildings that are smart, sustainable, and...
The iconic 125-year-old Lick Observatory on Mount Hamilton near San Jose, California, is facing the threat of closure...
Recent results from the Curiosity Mars rover have helped scientists formulate a plan for the next phase of its mission...
A new, remarkably powerful drug that cripples the hepatitis C virus (HCV) came to market last week, but it sells for $...
In pretoothbrush populations, gumlines would often be marred by a thick, visible crust of calcium phosphate, food...
- 12 December 2013 1:00 pm , Vol. 342 , #6164
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ScienceShot: Looking for Life on Mars? Dig Deeper
15 February 2013 6:08 pm
BOSTON—Curiosity’s newly drilled hole on the surface of Mars, completed last week, is our first peek at what’s under the surface of the red planet. And even as scientists start their analyses, a martian meteorite that arrived on Earth 12,000 years ago is yielding its own clues to life on Mars, strengthening the idea that we’ll have to go deeper to find life, if it’s there at all. The meteorite, found in 1979, has long been known to contain small amounts of the chemicals nitrate and perchlorate, which could be good or bad for life: To some modern life forms on Earth, perchlorate is toxic, but to others in oxygen-free conditions, and to those in the early days of Earth, it was a source of energy for microbes. But whether those chemicals originated on Mars or crept in during the meteorite’s 12,000-year tenure on Earth was uncertain. Now that question, at least, has been solved: They’re definitely from Mars, scientists reported here today at the annual meeting of AAAS (which publishes ScienceNOW). What’s more, new analyses of data from Curiosity’s predecessor, Phoenix, suggest that the red planet’s surface also contains highly reactive chemicals called oxychlorines, intermediaries between perchlorates and chlorines. With just a little water, oxychlorines react speedily with any organic matter in soils. So if scientists find any organics on Mars, that means the planet is very, very dry—at least nowadays—which, paradoxically isn’t good news for life. But that doesn’t preclude the possibility that life is buried deep, said lead author and planetary scientist Sam Kounaves of Tufts University in Medford, Massachusetts. In just the last 10 years, life has been found in all sorts of surprising—deep, dark, inhospitable—spots on Earth, he said. "We had to go pretty far down. So if Earth is any guide, we’ve got a long way to go."
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*Correction, 1:08 p.m., 19 February: The text has been changed to reflect that the data was collected by the Phoenix lander, not the Opportunity rover. Also, the chemicals found on Mars's surface were oxychlorines, not oxychlorate.