Babylonians Tracked Jupiter With Advanced Tools

Ancient tablets describe math that was thought to have been invented over 1,000 years later, rewriting the history books.

The Babylonians’ techniques outshine those used by contemporary Greek and Egyptian astronomers—and shockingly mirror the mean speed theorem, a mathematical description of motion developed by a 14th-century English group known as the Oxford Calculators.

And the findings probably represent the tip of a mathematical iceberg. “There are thousands of tablets in various museums that were never translated,” says Ossendrijver, “and often we can translate a tablet but don’t understand what is going on until much later.”Researchers have long known that the Babylonians, who lived in what is now Iraq, had considerable mathematical skill: They successfully approximated the square root of 2 and understood the Pythagorean theorem nearly 4,000 years ago—more than a millennium before Pythagoras was born.

They were also talented astronomers, maintaining nightly catalogs detailed enough to record the passage of Halley’s comet. Babylonians regularly used arithmetic to boost their astronomical predictions.

But no one had ever found a Babylonian astronomical calculation that leveraged their impressive knowledge of pure geometry, until Mathieu Ossendrijver of Germany’s Humboldt University of Berlin spent 13 years deciphering what he described as a “small bunch of four weird trapezoid computations” between 2,000 and 2,400 years old.

Ossendrijver was the first to notice that the tablets—stored in the British Museum since the 1880s—had something to do with the planet Jupiter. However, they didn’t make much sense without knowing how the Babylonians encoded aspects of Jupiter’s motion, such as its appearances on the horizon.

Such a find also speaks to the human spirit of discovery—both of the ancient astronomers who gazed at the heavens, and the modern researchers who seek to reconstruct their understanding of the cosmos.