The artifact “Plimpton 322” (photograph), for 80 years in the collections of Columbia University, is at least 3,700 years old. It comes from Mesopotamia, from the territory of ancient (and mythical) Babylonia. All these decades archaeologists and mathematicians have racked their brains over what it says. Until last summer a team from the Australian University of New South Wales announced that they had cracked it:
…This is an impressive mathematical work, created by geniuses without any doubt… What it contains is not simply the oldest trigonometric table, but mainly the most absolutely accurate trigonometric table ever made up to now… The Babylonian mathematicians may have been forgotten for 3,000 years, but this work may have practical applications in today’s informatics and in mathematics education. It is a rare example of an ancient world that teaches us something new… With Plimpton 322, we have in our hands a simpler and far more accurate trigonometry, which clearly has advantages over our own…
Daniel Mansfield’s enthusiasm, a professor of mathematics and statistics at the university, is not unjustified. The Babylonian mathematicians did not use 10 as the base of their calculations (“decimal system”) but 60. This gave them the ability for very high precision, especially in measurements smaller than the unit. And the estimation after the “decoding” of Plimpton 322 is that it was a work tool: it provided an easy method for making quick calculations either in land demarcation (of estates) or in the construction of palaces, temples, etc.
Last but not least: reading Plimpton 322 proves beyond any doubt that the famous “Pythagorean theorem” was not at all …Pythagorean! It was well known and thoroughly studied in Mesopotamia at least ten centuries before Pythagoras. It somehow “got around” (after all, it wasn’t a state secret!) and, with a 1000-year delay, reached our neck of the woods…
But let’s not blame Pythagoras. He was Greek too: he copied and passed off as his own something that others had done long before him…