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.

                              2024 September 16
   [2]The cratered surface of a large body is shown: Mercury. The largest
   feature visible is a large impact crater with two rings, near the image
    center. Arms from the BepiColumbo spacecraft that took the image are
    seen extending into the image from the top and the right. Please see
               the explanation for more detailed information.

                  Mercury's Vivaldi Crater from BepiColombo
            Image Credit: [3]ESA, [4]JAXA, [5]BepiColombo, [6]MTM

   Explanation: Why does this large crater on Mercury have two rings and a
   smooth floor? No one is sure. The unusual feature called [7]Vivaldi
   Crater spans 215 kilometers and was imaged again in [8]great detail by
   [9]ESA's and [10]JAXA's robotic [11]BepiColombo spacecraft on a
   [12]flyby earlier this month. A large circular feature on a rocky
   planet or moon is usually caused by either an [13]impact by a small
   asteroid or a comet fragment, or a [14]volcanic eruption. In the
   [15]case of [16]Vivaldi, it is possible that [17]both occurred -- a
   heavy strike that caused a smooth internal lava flow. [18]Double-ringed
   craters are rare, and the cause of the inner rings remains a [19]topic
   of research. The speed-slowing [20]gravity-assisted [21]flyby of
   [22]Mercury by [23]BepiColombo was in preparation for the spacecraft
   entering orbit around the [24]Solar System's [25]innermost planet in
   2026.

                       Tomorrow's picture: dusty heart
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    Authors & editors: [37]Robert Nemiroff ([38]MTU) & [39]Jerry Bonnell
                                 ([40]UMCP)
          NASA Official: Amber Straughn [41]Specific rights apply.
            [42]NASA Web Privacy, [43]Accessibility, [44]Notices;
                A service of: [45]ASD at [46]NASA / [47]GSFC,
                         [48]NASA Science Activation
                           & [49]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2409/MercuryCaloris_BepiColombo_1806.jpg
   3. https://www.esa.int/
   4. https://global.jaxa.jp/
   5. https://www.esa.int/Science_Exploration/Space_Science/BepiColombo
   6. https://www.esa.int/Science_Exploration/Space_Science/BepiColombo/Mercury_Transfer_Module
   7. https://en.wikipedia.org/wiki/Vivaldi_(crater)
   8. https://www.esa.int/Science_Exploration/Space_Science/BepiColombo/BepiColombo_s_best_images_yet_highlight_fourth_Mercury_flyby
   9. https://www.esa.int/About_Us/Corporate_news/ESA_facts
  10. https://global.jaxa.jp/about/jaxa/index.html
  11. https://sci.esa.int/web/bepicolombo/-/33022-summary
  12. https://youtu.be/vtP92WeCVYQ
  13. https://spaceplace.nasa.gov/impact-crater/
  14. https://apod.nasa.gov/apod/ap210303.html
  15. https://ui.adsabs.harvard.edu/abs/2012AGUFM.P33B1943B/abstract
  16. https://en.wikipedia.org/wiki/Antonio_Vivaldi
  17. https://www.smithsonianmag.com/smart-news/see-new-detailed-photos-of-mercury-from-a-spacecrafts-closest-flyby-yet-180985040/
  18. https://en.wikipedia.org/wiki/Peak_ring
  19. https://res.cloudinary.com/jerrick/image/upload/d_642250b563292b35f27461a7.png,f_jpg,fl_progressive,q_auto,w_1024/a3e47wjih6jh8ilxwxcz.jpg
  20. https://science.nasa.gov/learn/basics-of-space-flight/primer/
  21. https://apod.nasa.gov/apod/ap200504.html
  22. https://apod.nasa.gov/apod/ap190428.html
  23. https://science.nasa.gov/mission/bepicolombo/
  24. https://science.nasa.gov/solar-system/solar-system-facts/
  25. https://science.nasa.gov/mercury/
  26. https://apod.nasa.gov/apod/ap240915.html
  27. https://apod.nasa.gov/apod/archivepix.html
  28. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  29. https://apod.nasa.gov/apod/lib/aptree.html
  30. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  31. https://apod.nasa.gov/apod/calendar/allyears.html
  32. https://apod.com/feed.rss
  33. https://apod.nasa.gov/apod/lib/edlinks.html
  34. https://apod.nasa.gov/apod/lib/about_apod.html
  35. https://asterisk.apod.com/discuss_apod.php?date=240916
  36. https://apod.nasa.gov/apod/ap240917.html
  37. http://www.phy.mtu.edu/faculty/Nemiroff.html
  38. http://www.phy.mtu.edu/
  39. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  40. http://www.astro.umd.edu/
  41. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  42. https://www.nasa.gov/about/highlights/HP_Privacy.html
  43. https://www.nasa.gov/general/accessibility/
  44. https://www.nasa.gov/privacy/
  45. https://astrophysics.gsfc.nasa.gov/
  46. https://www.nasa.gov/
  47. https://www.nasa.gov/centers/goddard/
  48. https://science.nasa.gov/learners
  49. http://www.mtu.edu/