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 August 11
    [2]See Explanation. Clicking on the picture will download the highest
                        resolution version available.

                    Arp 87: Merging Galaxies from Hubble
      Image Credit: [3]NASA, [4]ESA, [5]Hubble Heritage Team ([6]STScI,
                                  [7]AURA)

   Explanation: This dance is to the death. Along the way, as these two
   large galaxies duel, a [8]cosmic bridge of stars, gas, and dust
   currently stretches over 75,000 [9]light-years and joins them. The
   bridge itself is strong evidence that these two immense star systems
   have [10]passed close to each other and experienced [11]violent tides
   induced by mutual gravity. As further evidence, the face-on spiral
   galaxy on the right, also known as NGC 3808A, exhibits many young blue
   star clusters produced in a burst of star formation. The twisted
   edge-on spiral on the left (NGC 3808B) seems to be wrapped in the
   material [12]bridging the galaxies and surrounded by a curious
   [13]polar ring. Together, the system is known as [14]Arp 87 and
   morphologically classified, technically, as [15]peculiar. While such
   interactions are drawn out over billions of years, repeated [16]close
   passages should ultimately result in the death of one galaxy in the
   sense that only one galaxy will eventually result. Although [17]this
   scenario does look peculiar, galactic mergers are thought to be common,
   with Arp 87 representing a stage in [18]this inevitable process. The
   [19]Arp 87 pair are [20]about 300 million light-years distant toward
   the constellation Leo. The [21]prominent edge-on spiral galaxy at the
   far left appears to be a more distant background galaxy and not
   involved in the on-going merger.

                     Tomorrow's picture: perseid meteors
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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]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/1908/Arp87_Hubble_2302.jpg
   3. https://www.nasa.gov/
   4. https://www.spacetelescope.org/
   5. https://heritage.stsci.edu/
   6. https://www.stsci.edu/
   7. https://www.aura-astronomy.org/
   8. https://apod.nasa.gov/apod/ap140715.html
   9. https://starchild.gsfc.nasa.gov/docs/StarChild/questions/question19.html
  10. https://apod.nasa.gov/apod/ap130514.html
  11. https://www.youtube.com/watch?v=QcDtJ_-jdMw
  12. https://apod.nasa.gov/apod/ap061111.html
  13. https://apod.nasa.gov/apod/ap141108.html
  14. http://heritage.stsci.edu/2007/36/index.html
  15. http://nedwww.ipac.caltech.edu/level5/Arp/frames.html
  16. https://apod.nasa.gov/apod/ap120717.html
  17. https://ui.adsabs.harvard.edu/abs/1972ApJ...178..623T/abstract
  18. http://www.cv.nrao.edu/~jhibbard/MergeSeq/mergeseq.html
  19. https://en.wikipedia.org/wiki/Arp_87
  20. http://hubblesite.org/newscenter/archive/releases/2007/36/fastfacts/
  21. https://apod.nasa.gov/apod/ap190329.html
  22. https://apod.nasa.gov/apod/ap190810.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. http://asterisk.apod.com/discuss_apod.php?date=190811
  32. https://apod.nasa.gov/apod/ap190812.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. http://www.mtu.edu/