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 March 18 [2]A dark brown cloud that appears similar to a shark is seen against a background filled with stars and less prominent blue-shaded nebulas. Please see the explanation for more detailed information. LDN 1235: The Shark Nebula Image Credit & Copyright: [3]Timothy Martin Explanation: There is no sea on Earth large enough to contain the Shark nebula. This [4]predator apparition poses us no danger as it is composed only of interstellar gas and [5]dust. Dark dust like that [6]featured here is somewhat like cigarette smoke and [7]created in the cool atmospheres of giant [8]stars. After expelling gas and [9]gravitationally recondensing, massive stars may [10]carve intricate structures into their birth cloud using their high energy light and fast [11]stellar winds as sculpting tools. The heat they generate evaporates the murky [12]molecular cloud as well as causing ambient hydrogen gas to disperse and glow red. During disintegration, we [13]humans can enjoy [14]imagining these [15]great clouds as [16]common icons, like we do for [17]water clouds on Earth. Including [18]smaller dust nebulae such as Van den Bergh 149 & 150, the [19]Shark nebula, sometimes cataloged as LDN 1235, spans about 15 light years and lies about 650 [20]light years away toward the constellation of the King of Aethiopia ([21]Cepheus). Explore Your Universe: [22]Random APOD Generator Tomorrow's picture: open space __________________________________________________________________ [23]< | [24]Archive | [25]Submissions | [26]Index | [27]Search | [28]Calendar | [29]RSS | [30]Education | [31]About APOD | [32]Discuss | [33]> __________________________________________________________________ Authors & editors: [34]Robert Nemiroff ([35]MTU) & [36]Jerry Bonnell ([37]UMCP) NASA Official: Amber Straughn [38]Specific rights apply. [39]NASA Web Privacy, [40]Accessibility, [41]Notices; A service of: [42]ASD at [43]NASA / [44]GSFC, [45]NASA Science Activation & [46]Michigan Tech. U. References 1. https://apod.nasa.gov/apod/archivepix.html 2. https://apod.nasa.gov/apod/image/2503/Shark_Martin_5441.jpg 3. https://www.astrobin.com/users/AccidentalAstronomers/ 4. https://oceantoday.noaa.gov/endoceansharks/ 5. http://apod.nasa.gov/apod/ap030706.html 6. https://www.astrobin.com/6ekkcw/ 7. https://en.wikipedia.org/wiki/Cosmic_dust#Dust_grain_formation 8. https://science.nasa.gov/universe/stars/ 9. https://www.youtube.com/watch?v=YbdwTwB8jtc 10. https://apod.nasa.gov/apod/ap221020.html 11. https://apod.nasa.gov/apod/ap000318.html 12. https://apod.nasa.gov/apod/ap230129.html 13. https://apod.nasa.gov/apod/ap190818.html 14. https://apod.nasa.gov/apod/ap120124.html 15. https://apod.nasa.gov/apod/ap141008.html 16. https://en.wikipedia.org/wiki/Pareidolia 17. https://cloudappreciationsociety.org/ 18. https://apod.nasa.gov/apod/image/1509/shark_toet_1000_anno.jpg 19. https://www.galactic-hunter.com/post/the-shark-nebula 20. https://spaceplace.nasa.gov/light-year/ 21. https://en.wikipedia.org/wiki/Cepheus_(constellation) 22. https://apod.nasa.gov/apod/random_apod.html 23. https://apod.nasa.gov/apod/ap250317.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.com/feed.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=250318 33. https://apod.nasa.gov/apod/ap250319.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://www.nasa.gov/general/accessibility/ 41. https://www.nasa.gov/privacy/ 42. https://astrophysics.gsfc.nasa.gov/ 43. https://www.nasa.gov/ 44. https://www.nasa.gov/centers/goddard/ 45. https://science.nasa.gov/learners 46. http://www.mtu.edu/