A new study by a team of researchers at Humboldt University has revealed that Babylonian astronomers calculated the position of Jupiter using geometric methods. The study examined three published and two unpublished cuneiform tablets that date from the period of 350 to 50 BCE. Although historians assumed that these kinds of calculations were first carried out in the 14th century and that Babylonians only used arithmetical methods, the new evidence reveals their use of geometric methods that were a form of precalculus.
Despite the fact that none of the tablets feature drawings, the texts describe a trapezoid that is used to compute area. Furthermore, each of the five tablets contain calculations of Jupiter's daily displacement as well as its total displacement along its orbit, both in degrees, and these calculations are present for the first 60 days following Jupiter's visibility 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," Mathieu Ossendrijver, author of the study, said in a press release. "It is this trapezoidal figure of which the area is computed on the other four tablets."
The calculations took place at least 14 centuries earlier than computations used by European scholars and anticipated scholastic philosopher Nicole Oresme's graphical methods that mirror the relations and computations in the Babylonian trapezoid procedures.
The findings were published in the Jan. 29 issue of Science.
