Built on Facts

On this date in history was one of the earliest known dates in history.

There’s lots of things we can date with certainty. In the last few hundred years most dates can be pegged pretty accurately. December 7, 1941 was the date of the Pearl Harbor attack. Nicholas I of Russia was born on July 6, 1796. So on and so forth, but things tend to get more fuzzy as we go back. Alfred the Great died on October 26, 899 but his birthday cannot be dated to any closer than “about 849″. For very distant events like the founding of Babylon it’s hard to get within centuries. Things like the C-T boundary event have error bars in the hundreds of thousands of years.

The oldest events that can be precisely dated are eclipses. The earth-moon system ticks long like clockwork, gently perturbed by other planets and the tidal friction dissipating energy at a small rate. Though these can’t be perfectly corrected for, eclipses can be accurately calculated quite far into the distant past. When these eclipses are discussed in archaeological inscriptions in conjunction with particular events we can specify their occurrence to the day.

On June 15, 763 BC a total eclipse appeared in Assyria. Mentioned both in Assyrian records and (possibly) the Biblical book of Amos, it’s the oldest specific date of which I’m aware in ancient near eastern history. More spectacularly but later, an eclipse on May 28, 585 BC ended a battle between the Medes and the Lydians by terrifying the combatants into an immediate peace agreement. If you don’t count an eclipse by itself as being a historical event, I believe this is the single oldest event which can be pinned to a specific date.

The Chinese were generally better at both record keeping and astronomy than the nations of the near east, and there are a number of very ancient eclipses which can be dated with certainty. The oldest and most famous of these probably occurred on October 22, 2134 BC. Legend has it that the two royal astronomers had been partying too hard to inform the emperor of the eclipse beforehand and were thus separated from their respective heads. And you thought tenure review was harsh! Though the date of this eclipse is known with certainty, it’s not known for certain that this was the specific eclipse involved in that legend. Several eclipses occurred within the potential time frame of the original writing of the legend and the October 22 date represents the one considered most likely to fit.

Physics is the “hardest” of the hard sciences and history is an often fuzzy social science. You wouldn’t necessary expect there to me many intersections between the two, but as often in science it happens surprisingly often.