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Birthday · July 21, 2014

Spacecraft Rosetta Shows Comet has Two Components

July 21, 2014

The stars above are ancient, but your chance to be here is exquisitely temporary.

Spacecraft Rosetta Shows Comet has Two Components

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APOD published July 21, 2014. Full image credits are on the original APOD entry below. A publication-date match, not a photo taken on your date. Independent of NASA.

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Spacecraft Rosetta Shows Comet has Two Components

Original APOD · July 21, 2014

Why does this comet's nucleus have two components? The surprising discovery that Comet 67P/Churyumov�Gerasimenko has a double nucleus came late last week as ESA's robotic interplanetary spacecraft Rosetta continued its approach toward the ancient comet's core. Speculative ideas on how the double core was created include, currently, that Comet Churyumov�Gerasimenko is actually the result of the merger of two comets, that the comet is a loose pile of rubble pulled apart by tidal forces, that ice evaporation on the comet has been asymmetric, or that the comet has undergone some sort of explosive event. Pictured above, the comet's unusual 5-km sized comet nucleus is seen rotating over the course of a few hours, with each frame taken 20-minutes apart. Better images -- and hopefully more refined theories -- are expected as Rosetta is on track to enter orbit around Comet Churyumov�Gerasimenko's nucleus early next month, and by the end of the year, if possible, land a probe on it.

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