The following article shares highlights and insights from one of our Expert Series events, which are exclusive for Young Scholars and their parents.
Authored by: John Steele
The earliest known texts to contain detailed records of astronomical observations and present mathematical methods for calculating certain phenomena of the moon and the planets are found on clay tablets inscribed with the cuneiform script which were found in the ruins of the ancient city of Babylon in modern Iraq.
These tablets date to the first millennium BCE, between two and three thousand years ago, and were first discovered and deciphered in the nineteenth century. The tablet are written in a language called Akkadian, which is a Semitic language related to Hebrew, Aramaic, and Arabic.
Unfortunately, many cuneiform tablets were damaged when they were found. Often, tablets were found broken into small pieces and one job of modern scholars is to try to put these fragments of tablets back together again. Roughly five thousand tablets are known which contain texts relating to astronomy.
Over the past 150 years, scholars have investigated these tablets using a combination of linguistic, astronomical, and mathematical analyses in order to understand which astronomical phenomena the Babylonians observed, how they made their observations, how they developed and used mathematical methods to calculate astronomical phenomena, and what astronomy was used for.
This work has shown that the Babylonians had developed and highly advanced astronomy capable of predicting things like lunar and solar eclipses, the first visibility of the new moon crescent (which marked the beginning of the Babylonian month), and the motion and phenomena of the five planets that can be seen using the unaided eye. Many tablets remain untranslated and unstudied, however, so there is still lots of work to do to fully understand Babylonian astronomy.
In the presentation we saw how many things that are still part of modern astronomy – and, more broadly, modern life – originated in Babylonia. For example, many of the constellations that we still use were first identified and named by the Babylonians. It was also the Babylonians who developed the concept of the twelve signs of the zodiac, and divided the circle into 360 degrees (called ‘UŠ’ by the Babylonians). Even the division of the hour into 60 minutes and a minute into 60 seconds has its origin in the Babylonian base-60 number system. We also saw how the Babylonians applied mathematical methods to the calculation of the motion and phenomena of the planets. And, we also explored what happens when a prediction goes wrong using the case of an astronomer who was arrested for incorrectly predicting an eclipse, causing people to perform an elaborate (and expensive) ritual when it was not necessary.
Things students can do to explore this topic further
Students who want to explore the history of Babylonian astronomy further might like to take a look at the online translations of the Babylonian Astronomical Diaries, which contain records of observations. Try comparing the Babylonian records with modern computer simulations using free planetarium software such as Stellarium. Note that the website gives the year using the so-called ‘astronomical dating system’ in which there is a year zero; this means that year 0 = 1 BCE, year -100 = 101 BCE, etc. Also, the Babylonian year doesn’t begin at the same time as our year. Try to see if you can figure out the rough equivalence between Babylonian months and our calendar by seeing when the Babylonian observations fit calculation.
Open access online editions and translations of many texts containing Babylonian astronomical observations are available at http://oracc.museum.upenn.edu/adsd/index.html
Translations and studies of many of the other texts I presented can be found in the books The Babylonian Astronomical Compendium MUL.APIN by Hermann Hunger and John Steele (Routledge, 2019) and Babylonian Mathematical Astronomy: Procedure Texts by Mathieu Ossendrijver (Springer, 2012). Unfortunately, these books are not available open access, but they may be available from major public and university libraries.
For a general introduction to Babylonian astronomy (and more!), see my book A Brief Introduction to Astronomy in the Middle East (Saqi Books, 2008) and the book The History and Practice of Ancient Astronomy by James Evans (Oxford University Press, 1998).
John Steele is Professor of the History of the Exact Sciences in Antiquity at Brown University. He is a historian of ancient science, in particular the astronomy and astrology of the ancient Babylonians. John grew up in the north of England and studied Physics (BSc 1995) and History of Science (PhD 1998) at Durham University. He is the author of more about one hundred research papers and six books including more recently The Babylonian Astronomical Compendium MUL.APIN (co-authored with Hermann Hunger, which contains an edition, English translation, and study of one of the earlier Babylonian astronomical texts. His 2008 book A Brief Introduction to Astronomy in the Middle East has recently been translated into Chinese and Persian.