<p>The European Space Agency launched the Rosetta spacecraft in 2004, beginning a decade-long mission to catch the comet 67P/Churyumov-Gerasimenko.</p>

Ten-Year Mission

The European Space Agency launched the Rosetta spacecraft in 2004, beginning a decade-long mission to catch the comet 67P/Churyumov-Gerasimenko.

Photograph by ESA/Rosetta/NAVCAM

Spacecraft Sees What a Comet Is Made Of

The Philae probe, which bounce-landed on a comet last year, has phoned home its findings.

Despite being in forced hibernation since its historic landing on a comet last November, the Philae space probe has given scientists their first closeup look at what these ancient and mysterious objects are made of, and how they were born during the solar system’s infancy.

The information beamed back to Earth before Philae went to sleep was enough to generate seven scientific papers, which appear in a special issue of the journal Science. Among the tantalizing results: Comet 67/P Churyumov-Gerasimenko, where Philae set down, has a surface that varies from hard as asphalt to soft as a sandy beach. Its interior isn’t like a rocky snowball, as scientists thought it might be, but rather a smooth mixture of dust

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