                        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 June 15
    Two images are shown side by side. On the left is a sunset seen from
   Earth, while on the right is a sunset seen from Mars. The Earth sunset
    is quite orange, while the Mars sunset is quite blue. The Sun appears
       angularly smaller from Mars than from the Earth. Please see the
                 explanation for more detailed information.

                             Two Worlds, One Sun
                 Left Image Credit & Copyright: Damia Bouic;
   Right Image Credit: NASA, JPL-Caltech, MSSS; Digital processing: Damia
                                    Bouic

   Explanation: How different does sunset appear from Mars than from
   Earth? For comparison, two images of our common star were taken at
   sunset, one from Earth and one from Mars. These images were scaled to
   have the same angular width and are featured here side-by-side. A quick
   inspection will reveal that the Sun appears slightly smaller from Mars
   than from Earth. This makes sense since Mars is 50% further from the
   Sun than Earth. More striking, perhaps, is that the Martian sunset is
   noticeably bluer near the Sun than the typically orange colors near the
   setting Sun from Earth. The reason for the blue hues from Mars is not
   fully understood, but thought to be related to forward scattering
   properties of Martian dust. The terrestrial sunset was taken in 2012
   March from Marseille, France, while the Martian sunset was captured in
   2015 by NASA's robotic Curiosity rover from Gale crater on Mars.

       APOD Turns 30!: Free Public Lecture in Cork, Ireland on June 24
                          Tomorrow's picture: S30E1
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       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Amber Straughn Specific rights apply.
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                           NASA Science Activation
                             & Michigan Tech. U.

