Regardless of the time period, it seems the skies have always held humanity’s attention. The Babylonians were no different. Previously, science historians assumed these ancient astronomers utilized arithmetical methods to track the movement of the stars and planets.
New research published in Science, however, points out that Babylonian astronomers working at least between 350 and 50 BCE were employing sophisticated geometric methods, techniques which historians previously believed did not arise until the 14th century.
“The idea of computing a body’s displacement as an area in time-velocity is usually traced back to 14th century Europe,” writes Prof. Mathieu Ossendrijver, a science historian at Berlin’s Humboldt Univ. “I show that in four ancient Babylonian cuneiform tablets, Jupiter’s displacement along the ecliptic is computed as an area of a trapezoidal figure obtained by drawing its daily displacement against time. This interpretation is prompted by a newly discovered tablet on which the same computation is presented in an equivalent arithmetical formulation.”
For years, Ossendrijver traveled to the British Museum to peruse their catalogue of Babylonian cuneiform tablets. The historian focused specifically on four tablets unearthed during the 19th century, which presented astronomical calculations and instructions for constructing a trapezoidal figure.
Ossendrijver, knowing of the Babylonian’s affinity for Jupiter due to its association with the deity Marduk, attempted to figure out if the trapezoidal figure somehow related to the gas giant.
A breakthrough came in 2014, when Assyriologist Hermann Hunger presented Ossendrijver with an old photograph of an uncatalogued tablet from the British Museum. Ossendrijver realized the computation on the tablet in the photograph matched those in the trapezoid descriptions.
Comparing all the tablets, Ossendrijver discovered the Jupiter connection. The computation covered a 60-day period that started when Jupiter became visible as a morning star.
“The crucial new insight provided by the new tablet without the geometrical figure is that Jupiter’s velocity decreases linearly within the 60 days. Because of the linear decrease a trapezoidal figure emerges if one draws the velocity against time,” said Ossendrijver. “It is this trapezoidal figure of which the area is computed on the other four tablets.”
The astronomers also calculated when Jupiter reached the halfway point by dividing the trapezoid into two equal areas.
According to Ossendrijver, similar techniques to the Babylonian method inscribed in cuneiform cropped up in the 14th century when mathematicians at Oxford’s Merton College developed the “Mertonian mean speed theorem.”
