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.

                                 2023 May 28
    [2]A pair of asteroids are shown with a large, elongated and cratered
   one on the left and a much smaller one on the far right. Please see the
                 explanation for more detailed information.

                      Ida and Dactyl: Asteroid and Moon
              Image Credit: [3]NASA, [4]JPL, [5]Galileo Mission

   Explanation: [6]This asteroid has a moon. The [7]robot spacecraft
   Galileo on route to [8]Jupiter in 1993 encountered and photographed two
   [9]asteroids during its long interplanetary voyage. The second minor
   planet it photographed, [10]243 Ida, was [11]unexpectedly discovered to
   have a moon. The tiny moon, [12]Dactyl, is only about 1.6 kilometers
   across and seen as a small dot on the right of the sharpened
   [13]featured image. In contrast, the [14]potato-shaped Ida is much
   larger, measuring about 60 kilometers long and 25 km wide. [15]Dactyl
   is the first moon of an asteroid ever discovered -- now many asteroids
   are [16]known to have moons. The names Ida and Dactyl are from
   [17]Greek mythology.

                      Tomorrow's picture: sea blue sky
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    Authors & editors: [29]Robert Nemiroff ([30]MTU) & [31]Jerry Bonnell
                                 ([32]UMCP)
          NASA Official: Phillip Newman [33]Specific rights apply.
              [34]NASA Web Privacy Policy and Important Notices
                A service of: [35]ASD at [36]NASA / [37]GSFC,
                         [38]NASA Science Activation
                           & [39]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2305/IdaDactyl_galileo_960.jpg
   3. https://www.nasa.gov/
   4. https://www.jpl.nasa.gov/
   5. https://solarsystem.nasa.gov/missions/galileo/overview/
   6. https://photojournal.jpl.nasa.gov/catalog/PIA00333
   7. https://solarsystem.nasa.gov/missions/galileo/overview/#otp_quick_facts
   8. https://solarsystem.nasa.gov/planets/jupiter/in-depth/
   9. https://solarsystem.nasa.gov/asteroids-comets-and-meteors/overview/
  10. https://solarsystem.nasa.gov/asteroids-comets-and-meteors/asteroids/243-ida/in-depth/
  11. https://i.imgflip.com/eyvnj.jpg
  12. https://en.wikipedia.org/wiki/Dactyl_(moon)
  13. https://photojournal.jpl.nasa.gov/catalog/PIA00069
  14. https://apod.nasa.gov/apod/ap200401.html
  15. https://en.wikipedia.org/wiki/Dactyl_(moon)
  16. https://apod.nasa.gov/apod/ap220927.html
  17. https://en.wikipedia.org/wiki/Greek_mythology
  18. https://apod.nasa.gov/apod/ap230527.html
  19. https://apod.nasa.gov/apod/archivepix.html
  20. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  21. https://apod.nasa.gov/apod/lib/aptree.html
  22. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  23. https://apod.nasa.gov/apod/calendar/allyears.html
  24. https://apod.nasa.gov/apod.rss
  25. https://apod.nasa.gov/apod/lib/edlinks.html
  26. https://apod.nasa.gov/apod/lib/about_apod.html
  27. https://asterisk.apod.com/discuss_apod.php?date=230528
  28. https://apod.nasa.gov/apod/ap230529.html
  29. http://www.phy.mtu.edu/faculty/Nemiroff.html
  30. http://www.phy.mtu.edu/
  31. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  32. http://www.astro.umd.edu/
  33. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  34. https://www.nasa.gov/about/highlights/HP_Privacy.html
  35. https://astrophysics.gsfc.nasa.gov/
  36. https://www.nasa.gov/
  37. https://www.nasa.gov/centers/goddard/
  38. https://science.nasa.gov/learners
  39. http://www.mtu.edu/