COMETS are supposed to be lumps of icy rubble covered in dark dust. But the most detailed images ever taken of a comet have revealed some surprising complexity.
In January, NASA’s Stardust spacecraft flew to within 236 kilometres of Comet Wild 2 and took 72 pictures of the comet’s nucleus. Detailed analyses of the images reveal steep-walled craters, spires, and pinnacles up to 100 metres high, and dozens of jets spewing gas and dust. “We were totally stunned by what we saw,” said Stardust principal investigator Donald Brownlee, of the University of Washington in Seattle, at a NASA press conference in Washington DC last week.…
