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The secret life of the snowflake revealed
These images show snow crystals that fell on Northern Ontario, Alaska, Vermont, the Michigan Upper Peninsula, and the Sierra Nevada mountains of California, captured in the seconds after they fell to earth. They were collected and photographed through a microscope by the world's leading snow crystal scientist, Kenneth Libbrecht, and are published in a new book.
Frozen water forms many types of crystal. Some of the more elaborate classification tables list 80 different varieties. The stellar dendrites you see here are the largest forms of snow crystal and perhaps the most beautiful, with the sectored plates coming in a close second, but there are also less photogenic simple prisms, columns, bullet shapes and needles and crystals that combine different types.
Most crystals have six-sided symmetry, though three- or 12-sided snow crystals also fall. You will never see a real snow crystal with four, five or eight sides. "I begin by letting snow fall on to a collection board, which I then examine to find interesting specimens," writes Libbrecht in Snowflakes. "The most perfectly formed crystals are usually found during light snowfalls with little wind, when the weather is especially cold."
Ancient Chinese scholars were the first to note the sixfold symmetry of snow crystals. Europeans were slower to catch on, but the study of snow nevertheless has a great tradition. In the early 17th century the astronomer and mathematician Johannes Kepler wrote a treatise on snow. Latterly, snow was studied by René Descartes, Robert Hooke and the English whaling captain William Scoresby. But the first man to capture snow crystals on camera was a Vermont farmer named Wilson Bentley, who was given a microscope as a teenager. Bentley was so enraptured by what he saw that he went on to devote his life to photographing thousands of snow crystals, and did much to persuade the world that they are all different.
Was he right? Pretty much, yes. Snow crystal growth depends on the temperature and pressure conditions in the cloud. As the history of every crystal is different, and they can take several hours to fall to earth, their forms are infinitely varied. There have been simple snow crystals that appear the same under a microscope. However at a molecular level, even these will be different. According to Libbrecht: "Each snowfall is a photographic adventure because each brings different crystals. And it's true - no two are exactly alike."
A Fernlike Stellar Dendrite snowflake. Photograph: Kenneth Libbrecht/Barcroft Media
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