Ice Volcano Seen on Titan

first_imgPlanetary scientists are reporting the possible discovery of an ice volcano on Saturn’s large moon Titan.  A large circular feature, 18 miles across, appears to have a caldera at the top, is surrounded by stress fractures, and appears warmer than the surroundings (warmer, relatively speaking: the mean surface temperature is -290° F).  The infrared pictures are somewhat indistinct due to the smoggy haze that obstructs views of the surface.    The discovery, announced in Nature,1,2 might explain the origin of the methane observed in Titan’s atmosphere.  The paper states that “a widespread methane ocean does not exist” on the surface.  Instead, cryovolcanism might provide a mechanism that could resupply the methane from below.  See also press releases from the Cassini website, JPL and the BBC.  [email protected] remarks that scientists were disappointed to find that Titan is as dry as a bone.1Louise Prokter, “Planetary science: Shades of Titan,” Nature 435, 749-750 (9 June 2005) | doi: 10.1038/435749a.2Sotin et al., “Release of volatiles from a possible cryovolcano from near-infrared imaging of Titan,” Nature 435, 786-789 (9 June 2005) | doi: 10.1038/nature03596.The lack of oceans of ethane and methane was a huge disappointment and surprise to planetary scientists.  They know that atmospheric methane is destroyed by the solar wind in short order – 100 million years as an upper limit (that’s only 1/45 the assumed age of Titan).  But they also expected the photolysis of methane to lead to the accumulation of hydrocarbons on the surface in the form of huge deposits of liquids.    Another surprise is the rarity of impact craters.  What keeps the methane supplied, and what keeps the surface smoothed over for long ages, are now major puzzles for those accustomed to thinking in terms of billions of years.  Trying to get all that methane out of one volcano seems a stretch.  Even with hundreds of such vents, how long could that continue?    The thought of a volcano erupting ice onto the surface of an alien moon, though, is pretty cool.(Visited 4 times, 1 visits today)FacebookTwitterPinterestSave分享0last_img