In a feat akin to hitting one high-speed bullet with another, NASA’s Stardust spacecraft flashed through the tail of a comet Friday morning, collecting tiny grains of primordial matter in an effort to better understand the origins of the solar system and perhaps even how life began on Earth.
After traveling nearly 2.5 billion miles in five years, the 16-foot-long probe passed within 143 miles of the nucleus of comet Wild-2 at approximately 11:22 a.m. PST, snapping 72 pictures of the four-mile-wide snowball of rock and ice. It collected a thumbnail-sized parcel of stardust that it will carry home to a Utah, landing in two years.
During its eight-minute plunge through the tail of the comet, Stardust encountered what scientists called a nightmare of millions of dust particles striking the craft at speeds of 14,000 mph. Only a pair of massive carbon-and-ceramic barriers called Whipple shields prevented the probe from being sandpapered into oblivion.
"Life is tremendously good," project manager Tom Duxbury of the National Aeronautics and Space Administration’s Jet Propulsion Laboratory said a few minutes after the craft emerged from the comet’s tail unscathed. "We’ve flown through the worst of it and are still in contact with our spacecraft."
Controllers at the Jet Propulsion Laboratory began receiving data from the probe shortly after it left the comet’s coma, or tail.
The first picture of Wild-2 showed a surprisingly spherical body pocked with massive sinkholes produced when ice and snow exposed to sunlight evaporate from the surface, a process called sublimation.
Researchers had predicted a more oblong shape because the comet is not large enough for gravity to pull it into a compact sphere. "I’m going to have to eat some crow about that," Duxbury said.
The massive pockmarks were also a surprise. Previous missions have taken pictures of comets Borrelley and Halley, but "none showed features like this," said astrophysicist Don Brownlee of the University of Washington.
The crater in the lower right-hand side of the picture "is one heck of a hole," Brownlee said. "You could put 30 to 50 Rose Bowls inside that crater."
The picture also shows at least five distinct jets where the comet is venting gases. With more time, researchers hope to match those jets up with specific features on the surface of the comet.
"The camera did us all proud today," said JPL’s Ray Newburn.
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