# Humble Pi

One lesson not easily forgotten from studying math is the phenomenon of "pi" - the ratio of a circle's circumference to its diameter, or an irrational number that's a wee bit larger than three.

Pi's presumed infinite nature has absorbed mathematicians - and others - for centuries. According to "That Book...of Perfectly Useless Information," newly published, actress Melissa Joan Hart can actually recite pi from memory to 400 decimal places - not quite as good as a modern computer, which can take pi to more than 200 billion digits, but it's still pretty impressive.

But students young and old might not be aware of news generated by physicists at Purdue University that suggests pi, or 3.14159...., might not be as truly random as once believed.

The scientists just completed a study (published in the latest issue of the International Journal of Modern Physics) comparing pi's "randomness" to that produced by some 30 different machines that generate random numbers. Though they found that the sequences derived from pi are an acceptable source of randomness (a big factor in producing hard-to-decrypt code, or solving particular physics problems), pi's string doesn't produce that randomness quite as effectively as the machines. Call it a case of *deus ex machina*.

For now, pi's integrity appears safe. "We do not believe these results imply anything about a pattern existing in pi's number set," says Ephraim Fischbach, a Purdue physics professor.

Whew. Still, it's good to have assumptions challenged. And to be reminded that even in mathematics, infinity finds a way of both showing itself - and keeping a secret.