                        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.

                                2026 March 31
    A half-lit moon is shown that is unfamiliar. The moon appears mostly
     gray but with some light patches. Two large craters appear near the
     terminator, and some large cracks are also evident. Please see the
                 explanation for more detailed information.

                       Uranus's Largest Moon: Titania
       Image Credit: NASA, Voyager 2; Processing & License: zelario12

   Explanation: Titania's tortured terrain is a mix of canyons, cliffs,
   and craters. NASA's interplanetary robot spacecraft Voyager 2 passed
   the largest moon of Uranus in 1986 and took the feature picture. That
   the trenches of Titania resemble those on another moon of Uranus,
   Ariel, indicate that Titania underwent some violent surface event
   possibly related to water freezing and expanding in its distant past.
   Although Titania is Uranus's largest moon, it is only about half the
   radius of Triton - the largest moon of Uranus's sister planet Neptune,
   which itself is slightly smaller than Earth's Moon. Titania, discovered
   by William Herschel in 1787, is essentially a large dirty iceball that
   is composed of about half water-ice and half rock. There is recent
   speculation that radioactive heating melts some underground ice into
   oceans.

                       Tomorrow's picture: open space
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       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Amber Straughn Specific rights apply.
                  NASA Web Privacy, Accessibility, Notices;
                      A service of: ASD at NASA / GSFC,
                           NASA Science Activation
                             & Michigan Tech. U.

