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 April 6
   [2]An astronaut is seen standing on the Moon next to an instrument with
   the lunar lander several meters in the distance. The dark of deep space
      covers the top of the frame. Please see the explanation for more
                            detailed information.

                       Moonquakes Surprisingly Common
                  Image Credit: [3]NASA, [4]Apollo 11 Crew

   Explanation: Why are there so many moonquakes? Analyses of
   [5]seismometers left on the moon during the [6]Apollo moon landings
   reveal a surprising number of [7]moonquakes occurring within 100
   kilometers of the surface. In fact, 62 [8]moonquakes were detected in
   data recorded between 1972 and 1977. [9]Many of these moonquakes are
   not only strong enough to [10]move furniture in a [11]lunar apartment,
   but the stiff rock of the moon continues to vibrate for many minutes,
   significantly longer than the softer rock [12]earthquakes on [13]Earth.
   The cause of the moonquakes remains unknown, but a [14]leading
   hypothesis include [15]tidal gravity from -- and [16]relative heating
   by -- our Earth. Regardless of the source, [17]future moon dwellings
   need to be built to withstand the frequent shakings. [18]Pictured here,
   [19]Apollo 11 astronaut [20]Buzz Aldrin stands beside a recently
   deployed [21]lunar seismometer, looking back toward the [22]lunar
   landing module.

              Explore Your Universe: [23]Random APOD Generator
                     Tomorrow's picture: yes, flocculent
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    Authors & editors: [35]Robert Nemiroff ([36]MTU) & [37]Jerry Bonnell
                                 ([38]UMCP)
          NASA Official: Amber Straughn [39]Specific rights apply.
            [40]NASA Web Privacy, [41]Accessibility, [42]Notices;
                A service of: [43]ASD at [44]NASA / [45]GSFC,
                         [46]NASA Science Activation
                           & [47]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2504/AldrinSeismometer_Apollo11_3000.jpg
   3. https://www.nasa.gov/
   4. https://www.nasa.gov/history/alsj/a11/a11.html
   5. https://en.wikipedia.org/wiki/Seismometer
   6. https://nssdc.gsfc.nasa.gov/planetary/lunar/apolloland.html
   7. https://en.wikipedia.org/wiki/Quake_(natural_phenomenon)#Moonquake
   8. https://ui.adsabs.harvard.edu/abs/1977Sci...196..979T/abstract
   9. https://science.nasa.gov/moon/moonquakes/
  10. https://www.youtube.com/watch?v=A75icqf9M6w
  11. https://www.nasa.gov/blogs/missions/2020/10/28/lunar-living-nasas-artemis-base-camp-concept/
  12. https://earthquake.usgs.gov/earthquakes/map/
  13. http://antwrp.gsfc.nasa.gov/apod/image/0208/earthlights02_dmsp_big.jpg
  14. https://ui.adsabs.harvard.edu/abs/2017JGRE..122.1487K/abstract
  15. https://en.wikipedia.org/wiki/Tidal_force
  16. https://i.pinimg.com/736x/21/aa/a2/21aaa23cfe7dbdd0a2201d68c94c1dbf.jpg
  17. https://apod.nasa.gov/apod/ap171025.html
  18. https://www.flickr.com/photos/nasacommons/9457418581/in/album-72157634973926806/
  19. https://www.nasa.gov/history/apollo-11-mission-overview/
  20. https://www.nasa.gov/former-astronaut-edwin-buzz-aldrin/
  21. https://science.nasa.gov/resource/apollo-11-seismic-experiment/
  22. https://apod.nasa.gov/apod/ap030920.html
  23. https://apod.nasa.gov/apod/random_apod.html
  24. https://apod.nasa.gov/apod/ap250405.html
  25. https://apod.nasa.gov/apod/archivepix.html
  26. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  27. https://apod.nasa.gov/apod/lib/aptree.html
  28. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  29. https://apod.nasa.gov/apod/calendar/allyears.html
  30. https://apod.com/feed.rss
  31. https://apod.nasa.gov/apod/lib/edlinks.html
  32. https://apod.nasa.gov/apod/lib/about_apod.html
  33. https://asterisk.apod.com/discuss_apod.php?date=250406
  34. https://apod.nasa.gov/apod/ap250407.html
  35. http://www.phy.mtu.edu/faculty/Nemiroff.html
  36. http://www.phy.mtu.edu/
  37. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  38. http://www.astro.umd.edu/
  39. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  40. https://www.nasa.gov/about/highlights/HP_Privacy.html
  41. https://www.nasa.gov/general/accessibility/
  42. https://www.nasa.gov/privacy/
  43. https://astrophysics.gsfc.nasa.gov/
  44. https://www.nasa.gov/
  45. https://www.nasa.gov/centers/goddard/
  46. https://science.nasa.gov/learners
  47. http://www.mtu.edu/