Byzantine records of solar eclipses showed how the Earth's rotation changed

Byzantine records of solar eclipses showed how the Earth's rotation changed

Japanese researchers have analysed the records of Byzantine scientists about solar eclipses, and observations confirm the change in the Earth's movement over time.

In their work, scientists have studied the records of the Byzantine Empire in order to determine and clarify the location of the complete solar eclipses observed in the Eastern Mediterranean from the fourth to the seventh centuries, and the records of this time, which coincides with the fall of Rome and the great relocation of peoples, are particularly scarce in other historical documents.

Although the original witness accounts of that period have largely been lost, scientists can use quotations and translations of ancient manuscripts in other documents, and in order to use the data obtained, scientists need accurate confirmation of the location and time of observation of the total eclipse, such as when stars appear in the day.

Through hard work, researchers were able to identify the likely time and location of five full solar eclipses, observed in the Eastern Mediterranean region in 346, 418, 484, 601 and 693; the regions in which the phenomenon could be seen were different from those in theory.

For example, the blackout of July 19, 418 could be seen in Constantinople. According to reports in the ancient text, it was so full that the stars appeared in the sky. The previous model assumed that the eclipse was impossible to observe in Byzantium this year.

Scientists use these observations to refine a model that describes how the earth's rotation around its axis has changed over time. Integrated results have shown that delta T should be increased in the fifth century and reduced in the VI and VII. This means that during this period the Earth's speed of rotation changed, first less than predicted and then more.