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 June 30
    [2]A dark background is filled with many light-blue ellipses. Toward
    the center, near circles that are labelled as the orbits of the inner
    planets of our Solar System are drawn. Please see the explanation for
                         more detailed information.

                  Orbits of Potentially Hazardous Asteroids
                Illustration Credit: [3]NASA, [4]JPL-Caltech

   Explanation: Are asteroids dangerous? Some are, but the likelihood of a
   dangerous asteroid striking the Earth during any given year is low.
   Because some past mass [5]extinction events have been linked to
   asteroid impacts, however, humanity has made it a priority to find and
   catalog those [6]asteroids that may one day affect [7]life on Earth.
   [8]Pictured here are the orbits of the over 1,000 known [9]Potentially
   Hazardous Asteroids (PHAs). These documented tumbling [10]boulders of
   rock and ice are over 140 meters across and will pass within 7.5
   million kilometers of Earth -- about 20 times the distance to the Moon.
   Although none of them will [11]strike the Earth in the next 100 years
   -- [12]not all PHAs have been discovered, and past 100 years, many
   orbits become hard to predict. Were an [13]asteroid of this size to
   [14]impact the Earth, it could raise [15]dangerous tsunamis, for
   example. To investigate Earth-saving strategies, NASA successfully
   tested the [16]Double Asteroid Redirection Test ([17]DART) mission last
   year. Of course, rocks and ice bits of much smaller size [18]strike the
   Earth every day, usually pose no danger, and sometimes create
   [19]memorable fireball and [20]meteor displays.

        Today is: [21]Asteroid Day Tomorrow's picture: three galaxies
     __________________________________________________________________

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    Authors & editors: [33]Robert Nemiroff ([34]MTU) & [35]Jerry Bonnell
                                 ([36]UMCP)
          NASA Official: Phillip Newman [37]Specific rights apply.
              [38]NASA Web Privacy Policy and Important Notices
                A service of: [39]ASD at [40]NASA / [41]GSFC,
                         [42]NASA Science Activation
                           & [43]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2306/phas_jpl_3254.jpg
   3. https://www.nasa.gov/
   4. https://www.jpl.nasa.gov/
   5. https://en.wikipedia.org/wiki/Cretaceous–Paleogene_extinction_event
   6. https://www.jpl.nasa.gov/asteroid-watch
   7. https://apod.nasa.gov/apod/ap230521.html
   8. https://photojournal.jpl.nasa.gov/catalog/PIA17041
   9. https://en.wikipedia.org/wiki/Potentially_hazardous_object
  10. https://commons.wikimedia.org/wiki/File:Balanced_Rock.jpg
  11. https://www.youtube.com/watch?v=_COcHHvte-0
  12. https://www.nasa.gov/mission_pages/WISE/multimedia/gallery/neowise/pia14734.html
  13. https://www.vaticanobservatory.org/sacred-space-astronomy/astronomy-picture-of-the-day-apod-authors-get-asteroid-named-after-them/
  14. https://en.wikipedia.org/wiki/Impact_event
  15. https://youtu.be/6scCF_8YN70
  16. https://www.nasa.gov/planetarydefense/dart
  17. https://apod.nasa.gov/apod/ap220927.html
  18. https://apod.nasa.gov/apod/ap210131.html
  19. https://apod.nasa.gov/apod/ap110123.html
  20. https://apod.nasa.gov/apod/ap121119.html
  21. https://asteroidday.org/
  22. https://apod.nasa.gov/apod/ap230629.html
  23. https://apod.nasa.gov/apod/archivepix.html
  24. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  25. https://apod.nasa.gov/apod/lib/aptree.html
  26. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  27. https://apod.nasa.gov/apod/calendar/allyears.html
  28. https://apod.nasa.gov/apod.rss
  29. https://apod.nasa.gov/apod/lib/edlinks.html
  30. https://apod.nasa.gov/apod/lib/about_apod.html
  31. https://asterisk.apod.com/discuss_apod.php?date=230630
  32. https://apod.nasa.gov/apod/ap230701.html
  33. http://www.phy.mtu.edu/faculty/Nemiroff.html
  34. http://www.phy.mtu.edu/
  35. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  36. http://www.astro.umd.edu/
  37. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  38. https://www.nasa.gov/about/highlights/HP_Privacy.html
  39. https://astrophysics.gsfc.nasa.gov/
  40. https://www.nasa.gov/
  41. https://www.nasa.gov/centers/goddard/
  42. https://science.nasa.gov/learners
  43. http://www.mtu.edu/