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 July 12
   [2]A spiral galaxy is shown with a yellow center, blue rings and spiral
   arms, and dark brown and red dust. The surrounding dark field contains
   both local stars and more distant galaxies. Please see the explanation
                       for more detailed information.

                   Rings and Bar of Spiral Galaxy NGC 1398
              Image Credit: [3]Mark Hanson; Data: [4]Mike Selby

   Explanation: Why do some spiral galaxies have a ring around the center?
   Spiral galaxy [5]NGC 1398 not only has a [6]ring of pearly stars, gas
   and [7]dust around its center, but a [8]bar of stars and gas across its
   center, and spiral arms that appear like ribbons farther out. The
   [9]featured deep image from [10]Observatorio El Sauce in [11]Chile
   shows the [12]grand spiral galaxy in impressive detail. [13]NGC 1398
   lies about 65 million [14]light years distant, meaning the light we see
   today left this galaxy when [15]dinosaurs were disappearing from the
   [16]Earth. The [17]photogenic galaxy is visible with a small telescope
   toward the constellation of the Furnace ([18]Fornax). The [19]ring near
   the center is likely an expanding [20]density wave of star formation,
   caused either by a [21]gravitational encounter with another galaxy, or
   by the galaxy's own [22]gravitational asymmetries.

                       Tomorrow's picture: open space
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    Authors & editors: [34]Robert Nemiroff ([35]MTU) & [36]Jerry Bonnell
                                 ([37]UMCP)
          NASA Official: Phillip Newman [38]Specific rights apply.
              [39]NASA Web Privacy Policy and Important Notices
                A service of: [40]ASD at [41]NASA / [42]GSFC,
                         [43]NASA Science Activation
                           & [44]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2307/Ngc1398_Hanson_2752.jpg
   3. https://www.instagram.com/hansonastronomy1
   4. https://www.facebook.com/masterdarksastro/
   5. https://en.wikipedia.org/wiki/NGC_1398
   6. https://apod.nasa.gov/apod/ap170710.html
   7. https://apod.nasa.gov/apod/ap030706.html
   8. https://apod.nasa.gov/apod/ap221016.html
   9. https://www.instagram.com/p/CtCsJ19N5tb/
  10. https://youtu.be/S4rFdr2Qmjk
  11. https://en.wikipedia.org/wiki/Chile
  12. https://apod.nasa.gov/apod/ap171226.html
  13. https://ui.adsabs.harvard.edu/abs/1995ApJ...447..159M/abstract
  14. https://spaceplace.nasa.gov/light-year/en/
  15. https://en.wikipedia.org/wiki/Cretaceous–Paleogene_extinction_event
  16. https://solarsystem.nasa.gov/planets/earth/overview/
  17. https://i.etsystatic.com/18172150/r/il/097703/4787375357/il_794xN.4787375357_7476.jpg
  18. https://en.wikipedia.org/wiki/Fornax
  19. https://apod.nasa.gov/apod/ap170807.html
  20. https://en.wikipedia.org/wiki/Density_wave_theory
  21. https://apod.nasa.gov/apod/ap130514.html
  22. https://en.wikipedia.org/wiki/Ring_galaxy#Bar_instability
  23. https://apod.nasa.gov/apod/ap230711.html
  24. https://apod.nasa.gov/apod/archivepix.html
  25. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  26. https://apod.nasa.gov/apod/lib/aptree.html
  27. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  28. https://apod.nasa.gov/apod/calendar/allyears.html
  29. https://apod.nasa.gov/apod.rss
  30. https://apod.nasa.gov/apod/lib/edlinks.html
  31. https://apod.nasa.gov/apod/lib/about_apod.html
  32. https://asterisk.apod.com/discuss_apod.php?date=230712
  33. https://apod.nasa.gov/apod/ap230713.html
  34. http://www.phy.mtu.edu/faculty/Nemiroff.html
  35. http://www.phy.mtu.edu/
  36. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  37. http://www.astro.umd.edu/
  38. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  39. https://www.nasa.gov/about/highlights/HP_Privacy.html
  40. https://astrophysics.gsfc.nasa.gov/
  41. https://www.nasa.gov/
  42. https://www.nasa.gov/centers/goddard/
  43. https://science.nasa.gov/learners
  44. http://www.mtu.edu/