Thursday, May 17, 2007

Hooke's flea

Telescopes and microscopes get ever bigger and more expensive. NASA is now planning the James Webb Space Telescope as a replacement for the Hubble. Its light-gathering mirrors will be seven times bigger than its predecessor. The Webb will let astronomers study the universe at ever greater distances from Earth, and therefore at earlier moments in the universe's history. Meanwhile, CERN's Large Hadron Collider will come on line next year, the biggest, most powerful particle accelerating machine ever. The LHC is a microscope of sorts, enabling physicists to observe fragments of subatomic matter that existed only in the instantaneous aftermath of the Big Bang. The Webb and the LHC are multibillion dollar projects.

Let us not forget, however, Hooke's flea. Robert Hooke was one of the first to use a microscope to extend the human visual sense. He recounted his observations in a delightful book, Micrographia, published in 1660, with illustrations of the things he studied -- seeds, hairs, plant cells, snowflakes, mites, flies, chiggers -- none more wonderful to behold than a big, fold-out drawing of a flea.

A flea! With shining armor like a knight, bristles like a porcupine, and legs like cocked springs. "The truth is," writes Hooke in his preface, "the science of nature has been already too long made only a work of the brain and the fancy: It is now high time that it should return to the plainness and soundness of observations on material and obvious things." In other words, no more disquisitions on angels dancing on the heads of pins. Attend instead to the fleas dancing on a dog's back.

Hooke was the first Curator of Experiments of the Royal Society, whose motto was "Take no one's word." The "no one" included the authors of holy books, popes, archbishops, Aristotlean philosophers, King Charles, and anyone else who laid claim to authority in matters of knowing. Henceforth reproducible experimental observation would be the gold standard of truth.

As we gush at the spectacular beauty of the new "Hubble's Ten Best," mind the flea, and the humble beginnings of a powerful way of knowing.