Large caches of clay tablets from the Ancient Near East still exist today. They have lain buried in palaces, schools and homes for over two thousand years. In recent centuries, over a million of these relics have been relocated to museum showcases and storage vaults.
Many tablets of the treasure trove deal with astronomy. One series from the ancient city of Babylon - the Diaries - embody the longest-running scientific study on record. They document more than 6 centuries of astronomical observations.
The archaic cuneiform script of the Diaries records astronomical and related observations. The earliest of these "regular watchings," as the Babylonians called them, is dated to 652 BCE (-651), the latest to 61 BCE (-60).
Historians have worked out dates for 180 of the surviving Diaries. These are published in a three volume set, Astronomical Diaries and Related Texts from Babylonia by Sachs & Hunger (1988-98). The books include photographs of the tablets, transliteration of the cuneiform text, and an English translation.
The extant Diaries are broken and large sections are missing. Still, the remaining pieces of each dated Diary typically register more than fifty observations, which enable researchers to determine a unique date.
The inquiry presented in the following frames explores whether the dates that historians attribute to the tablets are firmly established.
The observations logged in the Diaries reflect the aims and distinctive techniques of Babylonian astronomy. To corroborate the date historians ascribe to an observation, the Babylonian format must first be converted into modern terms, which can then be compared to a computer-generated representation of the sky. A close match between the computation and the Babylonian record indicates the assigned date is valid.
The analysis assumes that the linguistic translations of the cuneiform texts are accurate, and only examines the astronomical evidence.
On the face of it, this exercise of matching the Babylonian record to modern computations seems pointless. Historians of astronomy worked diligently to evaluate the Babylonian observations, and there are no obvious grounds for repeating their calculations.
Still, some long-standing astronomical disputes resist a denouement. Despite centuries of scholarly study, contentious issues concerning Ptolemy's Almagest remain unresolved.
Perhaps a comprehensive inspection of the Diaries will reveal that Babylonian astronomy is open to question.
If computed values do little more than loosely match the Babylonian data, or if the text is replete with "scribal" errors (which may mask incorrectly assigned dates), then the dating of the tablets would be suspect.
When the line of a Diary states ìthe 18th, Venus was balanced 1 cubit 4 fingers below alpha Leonisî, how close to the star does the computed sky place Venus on the inferred date?
In order to test the dates historians attribute to the Diaries, observations from several tablets were randomly selected for review. The analysis and results are presented in the following frames.
Additionally, a supplement provides the tools needed to render Babylonian astronomy accessible. A step-by-step introduction to TheSky computer software enables a novice to explore Babylonian astronomy.
Readers of this site are encouraged to check the astronomy of the Diaries and to communicate their findings via email to the Chronology Forum.