ミステリーサークルをめぐる科学的考察

The first formal scientific comment on crop circles was published in Nature in July 1880 by John Capron, who speculated that the “circular spots” were induced by cyclonic winds (J. R. Capron, Nature 22, 290-291; 1880). A century later, meteorologist Terence Meaden, then at Dalhousie University in Halifax, Canada, refined Capron's theory to explain more recent crop-circle appearances across southern England. He proposed in 1980 that the airflows induced by local hillsides stabilized the position of whirlwinds long enough to carve the circles.
There was a simpler explanation. Four years earlier, artists Douglas Bower and David Chorley began creating a series of circles in Hampshire's barley and wheat fields after reading old news reports about a pattern imprinted on Australian marshlands, supposedly by a UFO. Their hopes of initiating a UFO hoax were frustrated by the interest in Meaden's whirlwind theory. A battle of wits ensued....
As in all art movements, crop-circle artists follow rules laid down by their founders. Respecting the Bower-Chorley tradition, many create their pictographs anonymously during the short midsummer nights, leaving the scene free of human traces. Their challenge lies in creating the escalating designs within these cultural constraints. Modern construction methods have helped: today's patterns are mapped out using computers, laser pointers and satellite equipment, and artists work in coordinated teams. Bower once used only a crude sight, consisting of a circular wire dangling from his cap, to guide his lines. Other traditionalists used wooden planks, string and garden rollers. Artists even used bar stools to vault over regions of undisturbed crop. But there are signs that modern techniques are reaching their limits: in 2009, for the first time, one pictograph was created over three nights, potentially compromising the secrecy tenet.

日本語で言うところの｢ミステリーサークル｣についての記事がNatureに載っていました。１ヶ月以上前のものなのですが面白かったので一部引用。
ミステリーサークルに関する最古の科学記事が、130年前のNatureに掲載されていたとは驚きです。その頃は低気圧性風が原因とされ、約100年経っても風説は科学界の定説だったようです。しかし1984年にBowerとChorleyが、UFO説を覆すためにミステリーサークル群を作成しだしたことで、風習が変わったとのこと。
今でも伝統にのっとり、ミステリーサークルは夏至の夜に人目を避けて作られるそうです。唯一の例外は2009年に３晩越しで作成されたものだとか。科学が進歩するにつれて、ミステリーサークルの図案も着々と進化していくのが楽しみです。