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 16
   [2]A bright spiral galaxy shows stars and colorful clous of gas in red,
       green and blue colors. The background is a dark field of stars.

            NGC 300: A Cosmic Gemstone with Stars and Gas Clouds
               Image Credit & Copyright: [3]Team Ciel Austral
     Text: [4]Cecilia Chirenti ([5]NASA [6]GSFC, [7]UMCP, [8]CRESST II)

   Explanation: [9]This sparkling, colorful gemstone is a spiral galaxy,
   [10]NGC 300. It is one of the closest [11]spiral galaxies to Earth,
   only about 6 million light-years away. But does it really [12]look like
   this? [13]Here is a more standard portrait of it. This unusual image
   combines the light from the [14]stars and [15]dust within the galaxy
   with the light from ionized clouds of [16]interstellar gas shown in red
   (Sulphur), green (Hydrogen) and blue (Oxygen). Combining red and green
   light in [17]different proportions makes yellow or orange light, most
   visible in the image. Light from other ionized gases is also [18]at
   work in neon signs, fluorescent tubes and street lights. These
   [19]massive clouds of ionized gas are typically created by young,
   massive stars that produce high-energy [20]ultraviolet radiation
   capable of ionizing the gas. Massive stars are [21]short-lived,
   compared with lighter stars like our sun, and explode as [22]supernovas
   at the end of their lives. Some of the colorful clouds in the image
   could be [23]hiding [24]supernova remnants.

                      Tomorrow's picture: What's next?
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    Authors & editors: [36]Robert Nemiroff ([37]MTU) & [38]Jerry Bonnell
                                 ([39]UMCP)
          NASA Official: Amber Straughn [40]Specific rights apply.
            [41]NASA Web Privacy, [42]Accessibility, [43]Notices;
                A service of: [44]ASD at [45]NASA / [46]GSFC,
                         [47]NASA Science Activation
                           & [48]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2607/ngc300.jpg
   3. https://www.cielaustral.com/contact2.htm
   4. https://science.gsfc.nasa.gov/sci/bio/cecilia.chirenti
   5. https://www.nasa.gov/
   6. https://www.nasa.gov/goddard/
   7. https://www.astro.umd.edu/people/cecilia-chirenti
   8. https://cresst2.umd.edu/
   9. https://www.cielaustral.com/galerie/photo197.htm
  10. https://en.wikipedia.org/wiki/NGC_300
  11. https://science.nasa.gov/universe/galaxies/types/#spiral-galaxies
  12. https://images.unsplash.com/photo-1606509779095-de8fd5187049
  13. https://apod.nasa.gov/apod/ap241202.html
  14. https://science.nasa.gov/universe/stars/
  15. https://en.wikipedia.org/wiki/Cosmic_dust
  16. https://cesar.esa.int/upload/201801/ism_booklet.pdf
  17. https://isle.hanover.edu/Ch06Color/Ch06ColorMixer.html
  18. https://en.wikipedia.org/wiki/Gas-discharge_lamp
  19. https://astronomy.swin.edu.au/cosmos/*/HII+Region
  20. https://science.nasa.gov/ems/10_ultravioletwaves/
  21. https://www.starinabox.net/
  22. https://spaceplace.nasa.gov/supernova/en/
  23. https://www.aanda.org/articles/aa/abs/2004/38/aa1058/aa1058.html
  24. https://chandra.harvard.edu/xray_sources/supernovas.html
  25. https://apod.nasa.gov/apod/ap260715.html
  26. https://apod.nasa.gov/apod/archivepix.html
  27. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  28. https://apod.nasa.gov/apod/lib/aptree.html
  29. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  30. https://apod.nasa.gov/apod/calendar/allyears.html
  31. https://apod.com/feed.rss
  32. https://apod.nasa.gov/apod/lib/edlinks.html
  33. https://apod.nasa.gov/apod/lib/about_apod.html
  34. https://asterisk.apod.com/discuss_apod.php?date=260716
  35. https://apod.nasa.gov/apod/ap260717.html
  36. https://www.mtu.edu/physics/department/faculty/nemiroff/
  37. https://www.mtu.edu/physics/
  38. https://inspirehep.net/authors/1073087
  39. http://www.astro.umd.edu/
  40. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  41. https://www.nasa.gov/about/highlights/HP_Privacy.html
  42. https://www.nasa.gov/general/accessibility/
  43. https://www.nasa.gov/privacy/
  44. https://science.gsfc.nasa.gov/astrophysics/
  45. https://www.nasa.gov/
  46. https://www.nasa.gov/centers/goddard/
  47. https://science.nasa.gov/learn/about-science-activation/
  48. http://www.mtu.edu/