A pair of pi enthusiasts have calculated the largest chunk of the mathematical constant yet, reaching just over 10 trillion digits. Alexander Yee and Shigeru Kondo, respectively a computer scientist in the US and a systems engineer in Japan, fought hard-drive failures and narrowly missed widespread technical disruptions due to the Japan earthquake to break their previous Guinness world record of 5 trillion digits. Read more

The late Russian composer Igor Stravinsky once said, "Musical form is close to mathematics - not perhaps to mathematics itself, but certainly to something like mathematical thinking and relationship." Musician Michael Blake expands on that idea with this fascinating video, in which he sets pi, the mathematical constant, to music up to 31 decimal places. He then makes a tiny symphony out of the ditty. Read more

A computer scientist claims to have computed the mathematical constant pi to nearly 2.7 trillion digits, some 123 billion more than the previous record. Fabrice Bellard used a desktop computer to perform the calculation, taking a total of 131 days to complete and check the result. Read more

The ratio of the circumference of a circle to its diameter has been known as a constant for several thousand years, although it was only named pi by Leonard Euler in 1737. The Ancient Babylonians thought that pi was 3 1/8, and they probably measured it experimentally by use of a thin rope. You can do this by driving a stake into the ground, stretching a rope from that stake to inscribe a circle as a groove, and then marking off the radius multiple times by placing the rope in the groove. It'll go round six and a quarter times, roughly. (Note that it's easy to measure off powers of a half by folding the rope at the midpoint, so it's not surprising that they settled on 3 1/8.)