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" Today, after 10 years of space travel, the Rosetta explorer became the first to orbit a comet. The best is yet to come\u2014the scientists behind the satellite are preparing to land a harpoon-like probe on the surface this November. Yet new information is already pouring in. What scientists have discovered is already starting to transform our understanding of Rosetta&amp;#039;s target comet, 67P/Churyumov-Gerasimenko (C-G for short), and cometary science. Here are three surprising facts we&amp;#039;ve already learned: 1. C-G looks nothing like we&amp;#039;d expect Holger Sierks, the lead scientist behind OSIRIS\u2014Rosetta&amp;#039;s 4-megapixel-camera\u2014explains that while Rosetta has been approaching its rendezvous with C-G for years, the probe is only just now getting its first snapshots of the comet&amp;#039;s core. &amp;quot;It took us up until June just to fill one single pixel of our camera,&amp;quot; Sierks says. Now that the satellite is a mere 60 miles away, more recent images have detailed C-G&amp;#039;s odd shape: something halfway between a rubber ducky and a lumpy potato. &amp;quot;It was so surprising to see that this is not a [smooth], hull-shaped body, as we&amp;#039;ve thought it&amp;#039;d be,&amp;quot; Sierks says. The scientists are still putting together why the comet might have such an odd shape. One possibility is that C-G is actually two comets that have been fused together, he says, although it&amp;#039;s also possible the comet was somehow carved\u2014through impacts or some other unknown force\u2014into the strange figure.  Close up detail focusing on a smooth region on the &amp;#039;base&amp;#039; of the &amp;#039;body&amp;#039; section of comet 67P/Churyumov-Gerasimenko. (Photo Credit: ESA/Rosetta/MPS for OSIRIS Team) 2. The surface is hotter than we guessed, and surprisingly ice-free Comets are largely composed of rock and ice, but strictly looking at the surface of C-G might make you think otherwise: &amp;quot;We recorded a maximum temperature that&amp;#039;s around [-63 degrees Fahrenheit],&amp;quot; says Fabrizio Capaccioni, the head of the mission&amp;#039;s thermal imaging camera. That temperature is hotter than the researchers would have guessed, and &amp;quot;that tells us that the first [inch] of the surface crust is porous, dusty, and contains almost no ice,&amp;quot; Capaccioni says. This is a big surprise to the scientists, many of whom expected to find a glassy, clean surface of crystal ice. But the comet still is icy below the surface, &amp;quot;and we see water coming out, so there must be a way for the water to escape,&amp;quot; Capaccioni says.  3. Despite its dry surface, C-G expels an astronomical amount of water\u2026 but not on its dark side Samuel Gulkis, the head of Rosetta&amp;#039;s water-tracking radio telescope, reported two months ago at a press briefing that C-G, though it is only 2.5 miles wide, expels so much water that &amp;quot;it would fill an Olympic-size swimming pool in about 100 days.&amp;quot; Today he&amp;#039;s back with more data and reports that &amp;quot;one of the interesting things we&amp;#039;ve seen is that on the dark side of the comet, there&amp;#039;s very little gas, [including water,] being produced.&amp;quot; The facts about C-G&amp;#039;s water content are perhaps the most pressing to the scientists involved. Cosmic questions ranging from where Earth&amp;#039;s water came from to where and under what conditions comets like C-G originate all hinge on understanding the water on comets. "^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.popularmechanics.com/space/deep-space/a11020/3-surprising-comet-facts-weve-already-learned-from-rosetta-17066196/>