Nonsymmetrical Snow Crystal

December 25, 2008


Photographer: Jim Foster, NASA/GSFC, Beltsville Agricultural Research Center
Summary Author: Jim Foster

The photo above was captured with a scanning electron microscope (SEM) and shows a stellar dendrite snow crystal with one of its arms noticeably elongated. It was imaged not long after falling to the surface at the Beltsville Agricultural Research Center. The SEM at this research facility is most often used for looking at mites and other agricultural pests but has been utilized to study snow crystals as well. As this odd appearing hexagonal crystal fell toward the ground, one arm obviously gathered more water vapor than did the other five. The preferential collection of vapor likely resulted from the orientation of this crystal as it descended -- falling through the lower atmosphere with one arm exposed to slightly more vapor. Because of their different histories, no two snow crystals are exactly identical.

Merry Christmas, Happy Holidays and all the best in the coming year!

Jim Foster, Martin Ruzek, Stu Witmer, and Drew Roman

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