Kepler and the snowflake

Originally posted at, the now-discontinued blog of the OU History of Science Collections. Neither this post nor any of its content should be taken as an official communication of the University of Oklahoma.

Johann Kepler, Strena (1611), University of Oklahoma Libraries, History of Science CollectionsToday when the University has shut down because of this beautiful snowfall, let’s remember Johann Kepler, one of the most innovative astronomers who ever lived. Yet his contributions reached far beyond the realm of astronomy – to meteorology, mathematics, geology, mineralogy and crystallography.

In 1611, Kepler published a little pamphlet as a New Years greeting for some friends. Entitled Strena, seu de Nive Sexangula, it contained a study of the snowflake. Kepler distinguished the way organisms grow from the growth of crystals by accretion, and pioneered geometrical methods for explaining crystal packing. The work stimulated inquiry in mineralogy for the next two centuries. Indeed, as recently as 1998, Thomas Hales provided what is generally regarded as a mathematical proof of one of Kepler’s conjectures about crystal packing (cf. “Kepler’s Conjecture“).

The Strena (1611) is quite rare, and illustrates the depth of the OU Kepler collection which includes first editions of all of his major works. 30 works by Kepler published before 1700 are held in the OU History of Science Collections. We have digitized the Strena and it is available in our online galleries. The Collections also hold an English translation: The Six-Cornered Snowflake, trans. Colin Hardie (Oxford: Clarendon Press, 1966). For a brief discussion of the Strena’s contents, see Cecil J. Schneer, “Kepler’s New Year’s Gift of a Snowflake,” Isis, 51: 1960, 531-545 (available online at JSTOR).

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