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.

                               2020 January 8
    [2]See Explanation. Clicking on the picture will download the highest
                        resolution version available.

                            Galaxies in the River
      Image Credit & [3]Copyright: [4]Star Shadows Remote Observatory,
                               [5]PROMPT, CTIO

   Explanation: Large galaxies grow by eating small ones. [6]Even our own
   galaxy engages in a sort of galactic [7]cannibalism, absorbing small
   galaxies that are too close and are [8]captured by the Milky Way's
   gravity. In fact, the [9]practice is common in the universe and
   illustrated by this striking pair of interacting galaxies from the
   banks of the southern constellation [10]Eridanus, [11]The River.
   Located over 50 million light years away, the large, distorted
   [12]spiral NGC 1532 is seen locked in a gravitational struggle with
   dwarf galaxy NGC 1531 (right of center), a struggle the smaller galaxy
   [13]will eventually lose. Seen edge-on, spiral NGC 1532 spans about
   100,000 light-years. Nicely detailed in this sharp image, the NGC
   1532/1531 pair is thought to be similar to the well-studied system of
   face-on spiral and small companion [14]known as M51.

                    Tomorrow's picture: happy perihelion
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    Authors & editors: [26]Robert Nemiroff ([27]MTU) & [28]Jerry Bonnell
                                 ([29]UMCP)
          NASA Official: Phillip Newman [30]Specific rights apply.
              [31]NASA Web Privacy Policy and Important Notices
                A service of: [32]ASD at [33]NASA / [34]GSFC
                           & [35]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2001/NGC1532-final3_4096r.jpg
   3. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
   4. http://www.starshadows.com/index.cfm
   5. http://user.physics.unc.edu/~reichart/promptteam.html
   6. https://apod.nasa.gov/apod/ap050529.html
   7. http://www.cosmotography.com/images/galaxy_cannibalism.html
   8. http://arxiv.org/abs/astro-ph/0407566
   9. https://www.nasa.gov/image-feature/goddard/2017/hubble-catches-a-galaxy-duo-by-the-hare
  10. http://www.hawastsoc.org/deepsky/eri/index.html
  11. https://apod.nasa.gov/apod/ap160102.html
  12. http://ourcolorfulcosmos.com/mazlin/galaxies/ngc-1531-2-widefield/
  13. https://apod.nasa.gov/apod/ap080619.html
  14. https://apod.nasa.gov/apod/ap150502.html
  15. https://apod.nasa.gov/apod/ap200107.html
  16. https://apod.nasa.gov/apod/archivepix.html
  17. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  18. https://apod.nasa.gov/apod/lib/aptree.html
  19. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  20. https://apod.nasa.gov/apod/calendar/allyears.html
  21. https://apod.nasa.gov/apod.rss
  22. https://apod.nasa.gov/apod/lib/edlinks.html
  23. https://apod.nasa.gov/apod/lib/about_apod.html
  24. http://asterisk.apod.com/discuss_apod.php?date=200108
  25. https://apod.nasa.gov/apod/ap200109.html
  26. http://www.phy.mtu.edu/faculty/Nemiroff.html
  27. http://www.phy.mtu.edu/
  28. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  29. http://www.astro.umd.edu/
  30. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  31. https://www.nasa.gov/about/highlights/HP_Privacy.html
  32. https://astrophysics.gsfc.nasa.gov/
  33. https://www.nasa.gov/
  34. https://www.nasa.gov/centers/goddard/
  35. http://www.mtu.edu/