Ken Libbrecht’s Field Guide to Snowflakes, Kenneth Libbrecht (2006)

If you ask someone to draw up a list of inventions that have shaped the modern world, it’s likely that a very important one will get overlooked: the microscope. But where would medicine, science and technology be without it? It opened a door in the cellar of the universe just as the telescope opened a door in the attic. We stepped through each door into a new world of beauty and strangeness. The difference is that, so far, only one of these new worlds has proved to be inhabited: the microscopic one. But snowflakes remind you that the microcosmos can interest physicists and mathematicians as well as biologists and doctors. It should interest artists and aestheticians too: this book will delight the eye as well as challenge and enrich the mind. Snowflakes are among the most beautiful of all natural objects, reminiscent now of ice-stars, now of crystalline trees, now of stained glass, now of surreal swords. Their symmetry is part of their appeal, but I think it’s also important that their symmetry is never complete: snowflakes partake both of mathematical perfection and of biological imperfection. They’re individual not just because no two are identical but because no two arms of a single snowflake are identical either.

But any two arms can still be very similar, which is an astonishing fact when you consider that they’re laid down blindly by a purely chemico-physical process. How does one arm know what the others are doing? Well, it doesn’t: it’s subject to the same fluctuations of the same environment. As air-currents move a snow-crystal inside a cloud, the temperature and moisture of the air change constantly and so do the crystal’s patterns of growth: “…since no two snowflakes follow exactly the same path, no two are exactly alike.” But snowflakes can be much more unalike than the uninitiated might guess. Some aren’t actually stars, but bullets, needles, columns and “arrowhead twins”. There are also snowflakes with twelve rather than six arms, and snowflakes large enough to have arms on their arms on their arms on their arms. Kenneth Libbrecht, a professor of physics at Caltech, examines all this and more in a book that should appeal to every age, every level of intelligence, and every level of interest in science. You don’t have to read the text that accompanies the beautiful photographs, but if you do you’ll find your appreciation of the photos deepened and enriched.

Either way, spare a thought for the book’s co-author: the humble but hugely powerful microscope. Unlike bacteria and protozoa, snowflakes were known and admired long before the microscope was invented, but they were never known then in their full beauty and wonder. And you don’t have to confine yourself to books like this to experience that for yourself: Libbrecht has a section on “Observing Snowflakes” that demonstrates once again how some of the best things in life are free, or nearly free. For the price of a simple hand-lens you can find new beauty in winter; with a microscope, you can find even more.