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.

                                2026 July 12
   [2]A starfield surrounds a complex background galaxy. The galaxy center
     is surrounded by numerous shells, some circular and concentric, but
    others colorful and filamentary. Please see the explanation for more
                            detailed information.

                   Galaxy NGC 474: Shells and Star Streams
     Image Credit & [3]License: [4]CFHT, [5]Coelum, [6]MegaCam, [7]J.-C.
              Cuillandre ([8]CFHT) & G. A. Anselmi ([9]Coelum)

   Explanation: What's happening to galaxy [10]NGC 474? The multiple
   layers of emission appear strangely complex given the relatively
   featureless appearance of the [11]elliptical galaxy in less deep
   images. The cause of the [12]shells is a topic of research, but they
   are possibly [13]tidal tails related to debris left over from absorbing
   numerous small galaxies in the past billion years. Alternatively, the
   shells may be like ripples in a pond, where the ongoing collision with
   the spiral galaxy just to the right of [14]NGC 474 is causing
   [15]density waves to ripple through the galactic giant. Regardless of
   the actual cause, the [16]featured image dramatically highlights the
   increasing evidence that the halos of some elliptical [17]galaxies are
   surprisingly complicated. Similarly, the halo of our own [18]Milky Way
   Galaxy is one example of such [19]unexpected intricacies. NGC 474 spans
   about 250,000 [20]light years and lies about 100 million light years
   distant toward the constellation of the Fish ([21]Pisces).

                      Tomorrow's picture: aurora below
     __________________________________________________________________

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    Authors & editors: [33]Robert Nemiroff ([34]MTU) & [35]Jerry Bonnell
                                 ([36]UMCP)
          NASA Official: Amber Straughn [37]Specific rights apply.
            [38]NASA Web Privacy, [39]Accessibility, [40]Notices;
                A service of: [41]ASD at [42]NASA / [43]GSFC,
                         [44]NASA Science Activation
                           & [45]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2607/NGC474_CfhtCoelum_1500.jpg
   3. https://creativecommons.org/licenses/by-sa/4.0/deed.en
   4. http://www.cfht.hawaii.edu/
   5. http://www.coelum.com/
   6. http://www.cfht.hawaii.edu/Instruments/Imaging/Megacam/
   7. http://www.cfht.hawaii.edu/~jcc/
   8. http://www.cfht.hawaii.edu/
   9. http://www.coelum.com/
  10. https://en.wikipedia.org/wiki/NGC_474
  11. https://en.wikipedia.org/wiki/Elliptical_galaxy
  12. https://apod.nasa.gov/apod/ap021111.html
  13. https://apod.nasa.gov/apod/ap100926.html
  14. https://ui.adsabs.harvard.edu/abs/1999IAUS..186..191T/abstract
  15. https://youtu.be/c5Us-jonCLA
  16. https://www.cfht.hawaii.edu/HawaiianStarlight/AIOM/English/2013/Images/Jul-Image2012-CFHT-Coelum.jpg
  17. https://science.nasa.gov/universe/galaxies/
  18. https://science.nasa.gov/mission/webb/science-overview/science-explainers/is-the-milky-way-unique/
  19. https://thumbs.dreamstime.com/b/dog-climbed-toilet-paper-completely-unwound-roll-all-over-bathroom-376936392.jpg
  20. https://spaceplace.nasa.gov/light-year/en/
  21. https://en.wikipedia.org/wiki/Pisces_(constellation)
  22. https://apod.nasa.gov/apod/ap260711.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.com/feed.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=260712
  32. https://apod.nasa.gov/apod/ap260713.html
  33. https://www.mtu.edu/physics/department/faculty/nemiroff/
  34. https://www.mtu.edu/physics/
  35. https://inspirehep.net/authors/1073087
  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://www.nasa.gov/general/accessibility/
  40. https://www.nasa.gov/privacy/
  41. https://science.gsfc.nasa.gov/astrophysics/
  42. https://www.nasa.gov/
  43. https://www.nasa.gov/centers/goddard/
  44. https://science.nasa.gov/learn/about-science-activation/
  45. http://www.mtu.edu/