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 13
     [2]A brown background is shown covered with a gray topping that has
      many holes. On the upper right, there is a deep hole in the brown
        background. In this hole is more gray topping. Please see the
                 explanation for more detailed information.

                           An Unusual Hole in Mars
       Image Credit: [3]NASA, [4]MRO, [5]HiRISE, [6]JPL, [7]U. Arizona

   Explanation: What created this unusual hole in Mars? Actually, there
   are numerous holes pictured in this [8]Swiss cheese-like landscape,
   with all-but-one of them showing a dusty, dark, Martian terrain beneath
   [9]evaporating, light, carbon dioxide ice. The most [10]unusual hole is
   on the upper right, spans about 100 meters, and seems to punch through
   to a lower level. Why [11]this hole exists and why it is surrounded by
   a circular crater remains a topic of [12]speculation, although a
   leading hypothesis is that it was created by a meteor impact. [13]Holes
   such as [14]this are of particular interest because they might be
   portals to lower levels that extend into expansive [15]underground
   caves. If so, these naturally occurring tunnels are relatively
   protected from the harsh surface of Mars, making them relatively good
   candidates to [16]contain Martian life. These pits are therefore also
   prime targets for [17]possible future spacecraft, robots, and even
   [18]human interplanetary explorers.

                      Tomorrow's picture: radio center
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     __________________________________________________________________

    Authors & editors: [30]Robert Nemiroff ([31]MTU) & [32]Jerry Bonnell
                                 ([33]UMCP)
          NASA Official: Amber Straughn [34]Specific rights apply.
            [35]NASA Web Privacy, [36]Accessibility, [37]Notices;
                A service of: [38]ASD at [39]NASA / [40]GSFC,
                         [41]NASA Science Activation
                           & [42]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2504/MarsPit_mro_2628.jpg
   3. http://www.nasa.gov/
   4. https://science.nasa.gov/mission/mars-reconnaissance-orbiter/
   5. https://www.uahirise.org/epo/about/
   6. http://www.jpl.nasa.gov/
   7. http://hirise.lpl.arizona.edu/
   8. https://apod.nasa.gov/apod/ap010327.html
   9. https://www.youtube.com/watch?v=WABthlGTy74
  10. https://apod.nasa.gov/apod/ap200301.html
  11. https://www.nasa.gov/image-feature/jpl/pia21636/a-south-polar-pit-or-an-impact-crater
  12. http://www.lifeinthedoglane.com/wp-content/uploads/2013/03/puppy-head-tilt.jpg
  13. https://apod.nasa.gov/apod/ap070528.html
  14. https://apod.nasa.gov/apod/ap070928.html
  15. https://2015.spaceappschallenge.org/project/lavamatic/
  16. https://phys.org/news/2024-11-volcanic-caves-advances-life-mars.html
  17. https://science.nasa.gov/planetary-science/programs/mars-exploration/
  18. http://en.wikipedia.org/wiki/The_Martian_Chronicles
  19. https://apod.nasa.gov/apod/ap250412.html
  20. https://apod.nasa.gov/apod/archivepix.html
  21. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  22. https://apod.nasa.gov/apod/lib/aptree.html
  23. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  24. https://apod.nasa.gov/apod/calendar/allyears.html
  25. https://apod.com/feed.rss
  26. https://apod.nasa.gov/apod/lib/edlinks.html
  27. https://apod.nasa.gov/apod/lib/about_apod.html
  28. https://asterisk.apod.com/discuss_apod.php?date=250413
  29. https://apod.nasa.gov/apod/ap250414.html
  30. http://www.phy.mtu.edu/faculty/Nemiroff.html
  31. http://www.phy.mtu.edu/
  32. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  33. http://www.astro.umd.edu/
  34. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  35. https://www.nasa.gov/about/highlights/HP_Privacy.html
  36. https://www.nasa.gov/general/accessibility/
  37. https://www.nasa.gov/privacy/
  38. https://astrophysics.gsfc.nasa.gov/
  39. https://www.nasa.gov/
  40. https://www.nasa.gov/centers/goddard/
  41. https://science.nasa.gov/learners
  42. http://www.mtu.edu/