                        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.

                              2024 February 26

                     Martian Moon Eclipses Martian Moon
   Video Credit: ESA, DLR, FU Berlin, Mars Express; Processing & CC BY 2.0
                            License: Andrea Luck

   Explanation: What if there were two moons in the sky -- and they
   eclipsed each other? This happens on Mars. The featured video shows a
   version of this unusual eclipse from space. Pictured are the two moons
   of Mars: the larger Phobos, which orbits closer to the red planet, and
   the smaller Deimos, which orbits further out. The sequence was captured
   last year by the ESA’s Mars Express, a robotic spacecraft that itself
   orbits Mars. A similar eclipse is visible from the Martian surface,
   although very rarely. From the surface, though, the closer moon Phobos
   would appear to pass in front of farther moon Deimos. Most oddly, both
   moons orbit Mars so close that they appear to move backwards when
   compared to Earth's Moon from Earth, both rising in west and setting in
   the east. Phobos, the closer moon, orbits so close and so fast that it
   passes nearly overhead about three times a day.

                     Tomorrow's picture: spaghetti star
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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.

