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. 2021 August 11 [2]The picture shows a rows of mammatus clouds photographed over Saskatchewan, Canada. Please see the explanation for more detailed information. Mammatus Clouds over Saskatchewan Image Credit & Copyright: [3]Michael F Johnston Explanation: When do cloud bottoms appear like bubbles? Normally, [4]cloud bottoms are flat. This is because moist warm air that rises and cools will [5]condense into water droplets at a specific [6]temperature, which usually corresponds to a very specific height. As water [7]droplets grow, an opaque cloud forms. Under some conditions, however, [8]cloud pockets can develop that contain large droplets of water or [9]ice that fall into clear air as they evaporate. Such [10]pockets may occur in [11]turbulent air near a [12]thunderstorm. Resulting [13]mammatus clouds can appear especially [14]dramatic if [15]sunlit from the side. The [16]mammatus clouds [17]pictured here, lasting only a few minutes, were photographed over [18]Regina, [19]Saskatchewan, [20]Canada, just after a storm in 2012. Meteor Shower Tonight: [21]Peak of the Perseids Tomorrow's picture: a beautiful trifid __________________________________________________________________ [22]< | [23]Archive | [24]Submissions | [25]Index | [26]Search | [27]Calendar | [28]RSS | [29]Education | [30]About APOD | [31]Discuss | [32]> __________________________________________________________________ Authors & editors: [33]Robert Nemiroff ([34]MTU) & [35]Jerry Bonnell ([36]UMCP) NASA Official: Phillip Newman [37]Specific rights apply. [38]NASA Web Privacy Policy and Important Notices A service of: [39]ASD at [40]NASA / [41]GSFC & [42]Michigan Tech. U. References 1. https://apod.nasa.gov/apod/archivepix.html 2. https://apod.nasa.gov/apod/image/2108/Mammatus_Johnston_2136.jpg 3. https://www.instagram.com/beautyandruin/ 4. https://www.quora.com/Why-do-some-clouds-have-flat-bottoms-What-causes-them-to-be-fluffy-on-top-but-flat-and-even-on-the-underside 5. http://www.weatherquestions.com/What_are_condensation_nuclei.htm 6. https://apod.nasa.gov/apod/ap130731.html 7. http://earthobservatory.nasa.gov/Library/GlobalClouds/ 8. https://scijinks.gov/clouds/ 9. https://www.atoptics.co.uk/halosim.htm 10. https://en.wikipedia.org/wiki/Pocket 11. https://en.wikipedia.org/wiki/Turbulence 12. https://apod.nasa.gov/apod/ap170226.html 13. http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/cld/cldtyp/oth/mm.rxml 14. http://www.youtube.com/watch?v=Mt0zXfEktuQ 15. https://i.pinimg.com/originals/11/dd/61/11dd6174e69c390dc90be5a517e9fb1c.jpg 16. https://en.wikipedia.org/wiki/Mammatus_clouds 17. https://www.instagram.com/p/CC_CxJxgJDq/ 18. https://youtu.be/LLDnB5n2YQA 19. https://en.wikipedia.org/wiki/Saskatchewan 20. https://en.wikipedia.org/wiki/Canada 21. https://blogs.nasa.gov/Watch_the_Skies/2021/07/30/the-perseids-are-on-the-rise/ 22. https://apod.nasa.gov/apod/ap210810.html 23. https://apod.nasa.gov/apod/archivepix.html 24. https://apod.nasa.gov/apod/lib/apsubmit2015.html 25. https://apod.nasa.gov/apod/lib/aptree.html 26. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search 27. https://apod.nasa.gov/apod/calendar/allyears.html 28. https://apod.nasa.gov/apod.rss 29. https://apod.nasa.gov/apod/lib/edlinks.html 30. https://apod.nasa.gov/apod/lib/about_apod.html 31. http://asterisk.apod.com/discuss_apod.php?date=210811 32. https://apod.nasa.gov/apod/ap210812.html 33. http://www.phy.mtu.edu/faculty/Nemiroff.html 34. http://www.phy.mtu.edu/ 35. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html 36. http://www.astro.umd.edu/ 37. https://apod.nasa.gov/apod/lib/about_apod.html#srapply 38. https://www.nasa.gov/about/highlights/HP_Privacy.html 39. https://astrophysics.gsfc.nasa.gov/ 40. https://www.nasa.gov/ 41. https://www.nasa.gov/centers/goddard/ 42. http://www.mtu.edu/