May 23 2002
From The Space Library
In an article in the journal Nature, scientist Paul M. Schenk provided evidence that Jupiter's moon Europa might not be able to support life, challenging many scientists' previous assessments about the potential for life on the moon. Astrobiologists had theorized that Europa might be able to support life, based on the possibility that it might possess a heat source, liquid water, and organic material, all necessary for life to exist. However, researchers had also known that Europa is covered with a shell of ice, which might be sufficiently thick to prevent sunlight and oxygen from reaching water below the icy surface, thereby impeding Europa's ability to support life. Using data obtained from NASA's Galileo and Voyager spacecraft, Schenk had calculated the thickness of Europa's ice shell by comparing the depths of impact craters on Europa with those on Callisto and Ganymede, two other moons of Jupiter. Schenk's analysis indicated that Europa's ice shell is at least 1 9-kilometers (12-miles) thick~nearly twice that suggested by previous studies and thick enough to prevent the existence of life. (Usha Lee McFarling, “Life on Jupiter Moon Likely on Thin (or Thick) Ice,” Los Angeles Times, 23 May 2002; Paul M. Schenk, “Thickness Constraints on the Icy Shells of the Galilean Satellites from a Comparison of Crater Shapers,” Nature 417, no. 6887 (23 May 2002): 419-421.)
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