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.

                               2025 January 17
    [2]See Explanation. Clicking on the picture will download the highest
                        resolution version available.

                       Supernova Remnant Cassiopeia A
      Image Credit: [3]NASA, [4]ESA, [5]CSA, [6]STScI; D. Milisavljevic
      (Purdue University), T. Temim (Princeton University), I. De Looze
                            (University of Gent)

   Explanation: [7]Massive stars in our Milky Way Galaxy live spectacular
   lives. Collapsing from vast cosmic clouds, their nuclear furnaces
   ignite and create heavy elements in their cores. After only a few
   million years for the most massive stars, the [8]enriched material is
   blasted back into interstellar space where star formation can begin
   anew. The expanding debris cloud known as Cassiopeia A is an example of
   this final phase of the [9]stellar life cycle. Light from the supernova
   explosion that created this remnant would have been first [10]seen in
   planet Earth's sky about 350 years ago, although it took that light
   11,000 years to reach us. [11]This sharp NIRCam image from the James
   Webb Space Telescope shows the still hot filaments and knots in the
   supernova remnant. The whitish, smoke-like outer shell of the expanding
   blast wave is about 20 light-years across. A series of light echoes
   from the massive star's cataclysmic explosion are also [12]identified
   in Webb's detailed images of the surrounding interstellar medium.

                      Tomorrow's picture: light-weekend
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    Authors & editors: [24]Robert Nemiroff ([25]MTU) & [26]Jerry Bonnell
                                 ([27]UMCP)
          NASA Official: Amber Straughn [28]Specific rights apply.
              [29]NASA Web Privacy Policy and Important Notices
                A service of: [30]ASD at [31]NASA / [32]GSFC,
                         [33]NASA Science Activation
                           & [34]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2501/CasA_nircam_4096.jpg
   3. https://www.nasa.gov/
   4. https://www.esa.int/
   5. https://www.asc-csa.gc.ca/eng/
   6. https://www.stsci.edu/
   7. https://en.wikipedia.org/wiki/Stellar_evolution#Massive_stars
   8. https://apod.nasa.gov/apod/ap190801.html
   9. https://universe.nasa.gov/stars/basics/
  10. https://spider.seds.org/spider/Vars/casA.html
  11. https://webbtelescope.org/contents/media/images/2023/149/01HGGZ4TPD8XFNPCBTZ2QYM0ZM
  12. https://science.nasa.gov/missions/webb/nasas-webb-reveals-intricate-layers-of-interstellar-dust-gas/
  13. https://apod.nasa.gov/apod/ap250116.html
  14. https://apod.nasa.gov/apod/archivepix.html
  15. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  16. https://apod.nasa.gov/apod/lib/aptree.html
  17. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  18. https://apod.nasa.gov/apod/calendar/allyears.html
  19. https://apod.nasa.gov/apod.rss
  20. https://apod.nasa.gov/apod/lib/edlinks.html
  21. https://apod.nasa.gov/apod/lib/about_apod.html
  22. http://asterisk.apod.com/discuss_apod.php?date=250117
  23. https://apod.nasa.gov/apod/ap250118.html
  24. http://www.phy.mtu.edu/faculty/Nemiroff.html
  25. http://www.phy.mtu.edu/
  26. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  27. http://www.astro.umd.edu/
  28. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  29. https://www.nasa.gov/about/highlights/HP_Privacy.html
  30. https://astrophysics.gsfc.nasa.gov/
  31. https://www.nasa.gov/
  32. https://www.nasa.gov/centers/goddard/
  33. https://science.nasa.gov/learners
  34. http://www.mtu.edu/