                        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 January 25
     A large irregularly shaped object is shown that is mostly brown and
      shows many craters. Please see the explanation for more detailed
                                information.

                         Phobos: Doomed Moon of Mars
              Image Credit: NASA, LPL (U. Arizona), MRO, HiRISE

   Explanation: This moon is doomed. Mars, the red planet named for the
   Roman god of war, has two tiny moons, Phobos and Deimos, whose names
   are derived from the Greek for Fear and Panic. These Martian moons may
   well be captured asteroids originating in the main asteroid belt
   between Mars and Jupiter or perhaps from even more distant reaches of
   our Solar System. The larger moon, Phobos, is indeed seen to be a
   cratered, asteroid-like object in this stunning color image from the
   robotic Mars Reconnaissance Orbiter, which can image objects as small
   as 10 meters. But Phobos orbits so close to Mars - about 5,800
   kilometers above the surface compared to 400,000 kilometers for our
   Moon - that gravitational tidal forces are dragging it down. In perhaps
   50 million years, Phobos is expected to disintegrate into a ring of
   debris.

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

