                        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.

                                 2025 May 30

                              Mars in the Loop
                 Image Credit & Copyright: Tunc Tezel (TWAN)

   Explanation: This composite of images spaced a weather-permitting 5 to
   9 days apart, from 2024 September 19 (top right) through 2025 May 18
   (bottom left), faithfully traces ruddy-colored Mars as it makes a
   clockwise loop through the constellations Gemini and Cancer in planet
   Earth's night sky. You can connect the dots and dates with your cursor
   over the image, but be sure to check out this animation of the Red
   Planet's 2024/25 retrograde motion. Of course Mars didn't actually
   reverse the direction of its orbit. Instead, the apparent backwards
   motion with respect to the background stars is a reflection of the
   orbital motion of Earth itself. Retrograde motion can be seen each time
   Earth overtakes and laps planets orbiting farther from the Sun, the
   Earth moving more rapidly through its own relatively close-in orbit. In
   this case Mars' apparent eastward motion began to reverse around
   December 8, when it seemed to linger near open star cluster M44 in
   Cancer. After wandering back to the west, under Gemini's bright stars
   Castor and Pollux, Mars returned to pose near M44 by early May. At its
   brightest near opposition on 2025 January 16, Mars was a mere 96
   million kilometers away.

                       Tomorrow's picture: afterimage
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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.

