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No. 38: Mar-Apr 1985

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Two Snowflake Anomalies

Rarely is there anything in the scientific literature suggesting that anything about snowflakes could possibly be mysterious. Surprisingly, two articles on snowflake anomalies have appeared recently.

To form at all above -40�F, snowflakes supposedly require a solid seed or nucleus around which ice can crystallize -- or so scientists have assumed for many years. It was long believed that airborne dust, perhaps augmented by extraterrestrial micrometeoroids, served as the necessary nuclei. But cloud studies prove that there are about a thousand times more ice crystals than dust nuclei. Now, some are convinced that bacteria blown off plants and flung into the air by ocean waves are the true nuclei of atmospheric ice crystals. Remember this the next time you tast a handful of snow!

(Carey, John; "Crystallizing the Truth," National Wildlife, 23:43, December/ January 1985.)

Comment. The possibility that the fall of snow and all other forms of precipitation is largely dependent upon bacter-ia brings to mind the Gaia Hypothesis; that is, all life forms work in unison to further the goals of life.

The second item is from Nature and is naturally more technical. After reviewing the great difficulties scientists are having in mathematically describing the growth of even the simplest crystal, the author homes in on one of the fascinating puzzles of snowflake growth:

"The aggregation of particles into a growing surface will be determined exclusively by local properties, among which surface tension and the opportunities for energetically advantageous migration will be impor tant. But the symmetry of a whole crystal, represented by the exquisite six-fold symmetry of the standard snowflake, must be the consequence of some cooperative phenomenon involving the growing crystal as a whole. What can that be? What can tell one growing face of a crystal (in three dimensions this time) what the shape of the opposite face is like? Only the lattice vibrations which are exquisitely sensitive to the shape of the structure in which they occur (but which are almost incalculable if the shapes are not simply regular)."

(Maddox, John; "No Pattern Yet for Snowflakes," Nature, 313:93, 1985.)

Comment. It is amusing that this usually fairly open-minded journal Nature once blasted Sheldrake's A New Science of Life as a good candidate for burning. It is in this book that Sheldrake proposed morphogenetic fields as the explanation of crystal growth. Morphogenetic fields seem at least as reasonable as "vibrations".

Anomalous snowflakes

From Science Frontiers #38, MAR-APR 1985. � 1985-2000 William R. Corliss