                        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.

                               2022 January 27

                          Western Moon, Eastern Sea
                     Image Credit & Copyright: Tom Glenn

   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, taken during a period of favorable tilt, or
   libration of the lunar nearside, the Eastern Sea can be found near top
   center in this sharp telescopic view, extremely foreshortened 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, ripples in the lunar crust, are a little
   easier to spot in spacecraft images of the Moon, though. 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
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       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Phillip Newman Specific rights apply.
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