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 December 31 [2]A starfield filled with a diffuse red glow has an unusual nebula on the lower left. The nebula has bright red filaments that curve down and appear to be reminiscent of a waterfall on Earth. Please see the explanation for more detailed information. HH-222: The Waterfall Nebula Image Credit & Copyright: [3]Mike Selby Explanation: What created the Waterfall Nebula? The origin is still being researched. The structure, officially designated [4]Herbig-Haro 222, appears in the region of [5]NGC 1999 in the [6]Great Orion Molecular Cloud complex. The elongated gaseous stream stretches about ten [7]light years but appears similar to a long [8]waterfall on Earth. [9]Recent observations indicate that [10]HH-222 is likely a gigantic gaseous [11]bow shock, similar to a [12]wave of water caused by a fast-moving ship. The origin of this [13]shock wave is thought to be a [14]jet outflow from the multiple [15]star system [16]V380 Orionis off the lower left of the frame. Therefore, gas [17]does not flow along the waterfall, but rather the entire structure moves toward the upper right. The [18]Waterfall Nebula lies about 1,500 [19]light years away toward the [20]constellation of Orion. The [21]featured image was captured earlier this month from [22]El Sauce Observatory in [23]Chile. Jigsaw Nebula: [24]Astronomy Puzzle of the Day Tomorrow's picture: open space __________________________________________________________________ [25]< | [26]Archive | [27]Submissions | [28]Index | [29]Search | [30]Calendar | [31]RSS | [32]Education | [33]About APOD | [34]Discuss | [35]> __________________________________________________________________ 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/2512/WaterfallNeb_Selby_4000.jpg 3. https://throughlightandtime.com/about/ 4. https://en.wikipedia.org/wiki/Herbig–Haro_object 5. https://apod.nasa.gov/apod/ap180307.html 6. https://apod.nasa.gov/apod/ap070125.html 7. https://spaceplace.nasa.gov/light-year/ 8. https://apod.nasa.gov/apod/ap190112.html 9. https://ui.adsabs.harvard.edu/abs/2013AJ....146..118R/abstract 10. https://www.astroexplorer.org/details/aj481802f1 11. https://en.wikipedia.org/wiki/Bow_shock 12. https://youtu.be/95sQcSulRFM 13. https://www.grc.nasa.gov/www/k-12/VirtualAero/BottleRocket/airplane/shock.html 14. https://apod.nasa.gov/apod/ap250528.html 15. https://science.nasa.gov/universe/stars/ 16. https://en.wikipedia.org/wiki/V380_Orionis 17. https://media.istockphoto.com/id/1128004359/photo/close-up-scottish-fold-cat-head-with-shocking-face-and-wide-open-eyes-frighten-or-surprised.jpg?s=612x612&w=0&k=20&c=HglQ8Nf1PslTuI91T-dfhkln-iEbchjqfhGKCWTbaxg= 18. https://en.wikipedia.org/wiki/HH_222 19. https://science.nasa.gov/exoplanets/what-is-a-light-year/ 20. https://spaceplace.nasa.gov/constellations/ 21. https://throughlightandtime.com/hh-222-ha-rgb-rev-3-cdk-1000-26-dec-2025/ 22. https://youtu.be/shbwtlPIDI4 23. https://en.wikipedia.org/wiki/Chile 24. https://www.scigames.org/apps/webjigsaw2/index.php 25. https://apod.nasa.gov/apod/ap251230.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=251231 35. https://apod.nasa.gov/apod/ap260101.html 36. http://www.phy.mtu.edu/faculty/Nemiroff.html 37. http://www.phy.mtu.edu/ 38. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html 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://astrophysics.gsfc.nasa.gov/ 45. https://www.nasa.gov/ 46. https://www.nasa.gov/centers/goddard/ 47. https://science.nasa.gov/learners 48. http://www.mtu.edu/