                        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 July 10

                          Western Moon, Eastern Sea
                    Image Credit & Copyright: Guy Bardon

   Explanation: The Mare Orientale, Latin for Eastern Sea, is one of the
   most striking large scale lunar features. The youngest of the large
   lunar impact basins it's very difficult to see from an earthbound
   perspective. Still, captured on July 7 during a period of favorable
   tilt, or libration of the lunar nearside, the Eastern Sea can be found
   at the upper right in this sharp telescopic view. In the image, the
   large lunar mare is extremely foreshortened and stretches along the
   Moon's western edge. Formed by the impact of an asteroid over 3 billion
   years ago and nearly 1000 kilometers across, the impact basin's
   concentric circular features are ripples in the lunar crust. But they
   are a little easier to spot in more direct images of the region taken
   from lunar orbit. So why is the Eastern Sea at the Moon's western edge?
   The Mare Orientale lunar feature was named before 1961. That's when the
   convention labeling east and west on lunar maps was reversed.

                      Tomorrow's picture: light-weekend
     __________________________________________________________________

       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Amber Straughn Specific rights apply.
                  NASA Web Privacy, Accessibility, Notices;
                      A service of: ASD at NASA / GSFC,
                           NASA Science Activation
                             & Michigan Tech. U.

