Astronomy Picture of the Day

   [1]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 July 20
    [2]See Explanation. Moving the cursor over the image will bring up an
     annotated version. Clicking on the image will bring up the highest
                        resolution version available.

                               Lunar Nearside
      Image Credit: [3]NASA / [4]GSFC / Arizona State Univ. / [5]Lunar
                           Reconnaissance Orbiter

   Explanation: About 1,300 images from the Lunar Reconnaissance Orbiter
   spacecraft's wide angle camera were used to compose this spectacular
   view of a familiar face - [6]the lunar nearside. But why is there a
   lunar nearside? The Moon rotates on its axis and [7]orbits the Earth at
   the same rate, about once every 28 days. [8]Tidally locked in this
   configuration, the [9]synchronous rotation always keeps one side, the
   nearside, [10]facing Earth. As a result, featured in remarkable detail
   in the [11]full resolution mosaic, the [12]smooth, dark, lunar maria
   (actually lava-flooded impact basins), and rugged highlands, are
   well-known to earthbound skygazers. To find your favorite mare or large
   crater, just [13]follow this link or slide your cursor over the
   picture. The LRO images used to construct the mosaic were recorded over
   a two week period in December 2010.

                     Tomorrow's picture: pixels in space
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     __________________________________________________________________

    Authors & editors: [25]Robert Nemiroff ([26]MTU) & [27]Jerry Bonnell
                                 ([28]UMCP)
          NASA Official: Amber Straughn [29]Specific rights apply.
            [30]NASA Web Privacy, [31]Accessibility, [32]Notices;
                A service of: [33]ASD at [34]NASA / [35]GSFC,
                         [36]NASA Science Activation
                           & [37]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/1103/lroc_wac_nearside.jpg
   3. https://www.nasa.gov/
   4. https://www.gsfc.nasa.gov/
   5. https://lroc.sese.asu.edu/index.html
   6. https://lroc.im-ldi.com/images/293
   7. http://en.wikipedia.org/wiki/Orbit_of_the_Moon
   8. https://en.wikipedia.org/wiki/Tidal_locking
   9. https://svs.gsfc.nasa.gov/4709
  10. https://www.planetary.org/articles/the-two-faced-moon
  11. https://lroc.im-ldi.com/visit/exhibits/1/gallery/17
  12. https://apod.nasa.gov/apod/ap080208.html
  13. https://apod.nasa.gov/apod/image/2507/lroc_wac_nearside800lab.jpg
  14. https://apod.nasa.gov/apod/ap250719.html
  15. https://apod.nasa.gov/apod/archivepix.html
  16. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  17. https://apod.nasa.gov/apod/lib/aptree.html
  18. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  19. https://apod.nasa.gov/apod/calendar/allyears.html
  20. https://apod.com/feed.rss
  21. https://apod.nasa.gov/apod/lib/edlinks.html
  22. https://apod.nasa.gov/apod/lib/about_apod.html
  23. https://asterisk.apod.com/discuss_apod.php?date=250720
  24. https://apod.nasa.gov/apod/ap250721.html
  25. http://www.phy.mtu.edu/faculty/Nemiroff.html
  26. http://www.phy.mtu.edu/
  27. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  28. http://www.astro.umd.edu/
  29. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  30. https://www.nasa.gov/about/highlights/HP_Privacy.html
  31. https://www.nasa.gov/general/accessibility/
  32. https://www.nasa.gov/privacy/
  33. https://astrophysics.gsfc.nasa.gov/
  34. https://www.nasa.gov/
  35. https://www.nasa.gov/centers/goddard/
  36. https://science.nasa.gov/learners
  37. http://www.mtu.edu/