Reuters: An examination of the first material plucked from a comet is forcing scientists to rethink the nature of the frigid emissaries from the deepest reaches of our solar system, as well as the early solar system itself.Reporting their findings on Thursday, scientists who examined tiny grains retrieved by NASA’s Stardust spacecraft from comet Wild 2 (pronounced “vilt”) in 2004 found the comet, as expected, contained material from outside the solar system.