Small but spunky, hyperactive Comet Hartley 2 is shaped like a peanut and spews several jets of gas and dust on both its day and night sides, NASA’s EPOXI spacecraft has revealed. Intriguingly, the activity of the comet appears to be driven by the sudden venting into space of frozen carbon dioxide — dry ice — rather than frozen water, as has been found to be the case with many other comets, said principal mission scientist Mike A’Hearn of the University of Maryland in College Park.
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