December 12 News Items

Brain Stem Cells Sensitive to Space Radiation (Source: UF)
Measures to protect astronauts from health risks caused by space radiation will be important during extended missions to the moon or Mars, say researchers in a paper in Experimental Neurology. Using a mouse model designed to reveal even slight changes in brain cell populations, scientists found radiation appeared to target a type of stem cell in an area of the brain believed to be important for learning and mood control. The findings — from a team of researchers that includes NASA’s Kennedy Space Center and the McKnight Brain Institute of the University of Florida — suggest that identifying medications or physical shielding to protect astronauts from cosmic and solar radiation will be important for the success of human space missions beyond low Earth orbit.

“Our discovery does not present any adverse issues for the astronaut program because the ground-based dose and application of radiation we used were not comparable to that seen for existing space travel,” said UF's Dennis A. Steindler. “But the exceptional sensitivity of these neural stem cells suggests that we are going to have to rethink our understanding of stem cell susceptibility to radiation, including cosmic radiation encountered during space travel, as well as radiation doses that accompany different medical procedures.” Stem cells are important because they have the remarkable ability to renew themselves and produce many different cell types.

Gimpy Rover has Turned Up a Surprise on Mars (Source: San Francisco Chronicle)
Wow! After nearly four full years on Mars, those two robot rovers exploring the Red Planet are still at it, and their chief scientific shepherd reports for the first time that the partially crippled rover named Spirit has made "probably the most significant discovery" of its entire mission. Spirit's right front wheel - one of six on the vehicle - is jammed tight, and so the limping vehicle has been driving backward for months and dragging its sick wheel behind it like a useless crutch. But useless it's not.

On the opening day of the American Geophysical Union's annual meeting in San Francisco on Monday, Steven Squyres of Cornell, the Mars mission's principal investigator for science, disclosed that the rover's dragging wheel has serendipitously been working as a plow and has turned over yards and yards of Martian crust to reveal a startlingly white track of almost pure silica. The tracks also reveal small amounts of titanium. This silica is the very stuff deposited by the steamy fumaroles so common in Yellowstone National Park - and is also typical of the crusty mineral found around the margins of highly caustic hot springs. Titanium levels, he noted, are relatively high in the deposits left around fumaroles on Earth.

And also on Earth, Squyres noted, both those hot, wet environments are well-known as places that teem with living microbes of every kind - microbes that astrobiology researchers know as "extremophiles." What Spirit found in the white tracks dug up by its dragging wheel, said Squyres simply in what may one day prove to be the understatement of the year, "has implications for habitability." Visit http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2007/12/11/MN4OTRSU8.DTL&type=science to view the article.

Life's Building Blocks Found in Mars Rock (Source: Space.com)
Nobody knows for sure how life formed in the first place, but the thinking is that first you had to have the building blocks—organic compounds containing carbon and hydrogen. A new study finds these building blocks could have formed very early in the history of Mars. The research says nothing about whether there is life on Mars, but it does indicate that the raw material for life should be easy to drum up on any cold, rocky world. "Organic material occurs within tiny spheres of carbonate minerals in both the Martian and Earth rocks," said study leader Andrew Steele at the Carnegie Institution's Geophysical Laboratory. "We found that the organic material is closely associated with the iron oxide mineral magnetite, which is the key to understanding how these compounds formed."