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.

                               2019 October 4
    [2]See Explanation. Clicking on the picture will download the highest
                        resolution version available.

                           InSight on a Cloudy Day
           Image Credit: [3]NASA, [4]JPL-Caltech, [5]Mars InSight

   Explanation: [6]Clouds drift through the sky as the light fades near
   sunset in this three frame animated gif. The scene was captured on sol
   145 beginning around 6:30pm local time by a camera on the Mars InSight
   lander. Of course, InSight's martian day, sol 145, corresponds to Earth
   calendar date April 25, 2019. Under the 69 centimeter (2.3 foot)
   diameter dome in the foreground is the lander's sensitive
   [7]seismometer SEIS designed to detect marsquakes. Earthquakes reveal
   internal structures on planet Earth, and so tremors detected by SEIS
   can explore beneath the martian surface. In particular, two typical
   marsquakes were recorded by SEIS on [8]May 22 (sol 173) and [9]July 25
   (sol 235). The subtle tremors from the Red Planet are at very low
   frequencies though, and for listening have to be processed into the
   audio frequency range. In the sped up recordings external noises more
   prevalent on cool martian evenings and likely caused by mechanical
   shifts and contractions have been technically [10]dubbed dinks and
   donks.

                       Tomorrow's picture: moon shadow
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    Authors & editors: [22]Robert Nemiroff ([23]MTU) & [24]Jerry Bonnell
                                 ([25]UMCP)
          NASA Official: Phillip Newman [26]Specific rights apply.
              [27]NASA Web Privacy Policy and Important Notices
                A service of: [28]ASD at [29]NASA / [30]GSFC
                           & [31]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/1910/PIA23180_raw.gif
   3. https://www.nasa.gov/
   4. https://www.jpl.nasa.gov/
   5. https://mars.nasa.gov/insight/
   6. https://www.jpl.nasa.gov/spaceimages/details.php?id=PIA23180
   7. https://mars.nasa.gov/insight/spacecraft/instruments/seis/
   8. https://soundcloud.com/nasa/quake-sol-173
   9. https://soundcloud.com/nasa/quake-sol-235
  10. https://www.nasa.gov/feature/jpl/nasas-insight-hears-peculiar-sounds-on-mars
  11. https://apod.nasa.gov/apod/ap191003.html
  12. https://apod.nasa.gov/apod/archivepix.html
  13. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  14. https://apod.nasa.gov/apod/lib/aptree.html
  15. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  16. https://apod.nasa.gov/apod/calendar/allyears.html
  17. https://apod.nasa.gov/apod.rss
  18. https://apod.nasa.gov/apod/lib/edlinks.html
  19. https://apod.nasa.gov/apod/lib/about_apod.html
  20. http://asterisk.apod.com/discuss_apod.php?date=191004
  21. https://apod.nasa.gov/apod/ap191005.html
  22. http://www.phy.mtu.edu/faculty/Nemiroff.html
  23. http://www.phy.mtu.edu/
  24. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  25. http://www.astro.umd.edu/
  26. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  27. https://www.nasa.gov/about/highlights/HP_Privacy.html
  28. https://astrophysics.gsfc.nasa.gov/
  29. https://www.nasa.gov/
  30. https://www.nasa.gov/centers/goddard/
  31. http://www.mtu.edu/