                        Astronomy Picture of the Day

    Discover the cosmos! Each day a different image or photograph of our
      fascinating universe is featured, along with a brief explanation
                    written by a professional astronomer.

                                 2023 May 20

                              Galileo's Europa
     Image Credit: NASA, JPL-Caltech, SETI Institute, Cynthia Phillips,
                                Marty Valenti

   Explanation: Looping through the Jovian system in the late 1990s, the
   Galileo spacecraft recorded stunning views of Europa and uncovered
   evidence that the moon's icy surface likely hides a deep, global ocean.
   Galileo's Europa image data has been remastered here, with improved
   calibrations to produce a color image approximating what the human eye
   might see. Europa's long curving fractures hint at the subsurface
   liquid water. The tidal flexing the large moon experiences in its
   elliptical orbit around Jupiter supplies the energy to keep the ocean
   liquid. But more tantalizing is the possibility that even in the
   absence of sunlight that process could also supply the energy to
   support life, making Europa one of the best places to look for life
   beyond Earth. What kind of life could thrive in a deep, dark,
   subsurface ocean? Consider planet Earth's own extreme shrimp.

                      Tomorrow's picture: almost alien
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       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Phillip Newman Specific rights apply.
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                      A service of: ASD at NASA / GSFC
                             & Michigan Tech. U.

