                        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 January 22
   A black and white image of the Moon and a mountain are shown. Both are
     half lit by the Sun, with the other half shadowed. The half-moon is
    directly above the mountain peak. Please see the explanation for more
                            detailed information.

                        Shadows of Mountain and Moon
                 Image Credit & Copyright: Enzo Massa Micon

   Explanation: Can the Moon and a mountain really cast similar shadows?
   Yes, but the division between light and dark does not have to be
   aligned. Pictured, a quarter moon was captured above the mountain
   Grivola in Italy in early October of 2022. The Sun is to the right of
   the featured picturesque landscape, illuminating the right side of the
   Moon in a similar way that it illuminates the right side of the
   mountain. This lunar phase is called "quarter" because the lit fraction
   visible from Earth is one quarter of the entire lunar surface. Digital
   post-processing of this single exposure gave both gigantic objects more
   prominence. Capturing the terminator of this quarter moon in close
   alignment with nearly vertical mountain ridge required careful timing
   because the Earth rotates once a day.

                        Tomorrow's picture: sky wide
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       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Ryan Smallcomb; Specific rights apply.
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                      A service of: ASD at NASA / GSFC,
                           NASA Science Activation
                             & Michigan Tech. U.

