Ancient Babylonian astronomers were way ahead of their time, using sophisticated geometric techniques that until now had been considered an achievement of medieval European scholars.

That is the finding of a study published Thursday that analyzed four clay tablets dating from 350 to 50 B.C. featuring the wedge-shaped ancient Babylonian cuneiform script describing how to track the planet Jupiter's path across the sky.

"No one expected this," said Mathieu Ossendrijver, a professor of history of ancient science at Humboldt University in Berlin, noting that the methods delineated in the tablets were so advanced that they foreshadowed the development of calculus.