05 April 2011

In a Grain of Sand

There is something new under the Sun.  And it took some 42 years to find it.

In 1969, members of the Japanese Antarctic Research Expedition found nine meteorites lying on an icy field in the continent's Yamato Mountains.  Ever since, these specimens (along with the 40,000 meteorites collected in Antarctica afterward) have been avidly studied. Yet, even after four decades of analysis, some surprises remained. 

U.S. field team in Antarctica searching for meteorites in 1988-89.

One of the 1969 meteorites, known as Yamato 691, was recently examined with a transmission electron microscope located at NASA's Johnson Space Center in Houston, Texas.  This 21st-century nanotechnology allowed researchers from the United States, South Korea, and Japan to zoom in on isolated grains in the meteorite that are less than a hundredth the width of a human hair.  And what they discovered was an entirely new type of mineral, different from the 4,500 minerals already recognized by the International Mineralogical Association.  The researchers dubbed it "Wassonite," in honor of UCLA professor John Wasson, an international meteorite expert. 

Wassonite is made out of only two elements, sulfur and titanium.  Yet these atoms join up to form a crystalline structure that has not been previously observed in nature.  The mineral formed some 4.5 billion years ago, likely as part of an asteroid orbiting between Mars and Jupiter.  Further study of the novel crystal promises to offer new insights on conditions in the early solar system. "In the words of the great English poet William Blake," says Simon Clemett, a space scientist at the Johnson Space Center and co-discoverer of the new mineral, "we are now able 'to see the world in a grain of sand.'"
Picture Credit: Department of Earth and Planetary Sciences, Washington University in St. Louis

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