Researchers looked at historical records dating back to the 4th century to find a total solar eclipse.

Records of an eclipse observed nearly 1,500 years ago have revealed the history of Earth’s rotation and how our planet’s motion has changed in recent human history.

An article detailing the results was published in the journal Publications of the Astronomical Society of the Pacific.

Researchers studied the records of the Byzantine Empire, the eastern part of the Roman Empire that existed after the fall of the Western Roman Empire. – and identified five total solar eclipses observed in the eastern Mediterranean, pinpointing their likely timing and location. Previously, reports of solar eclipses during this time were rare.

Because eclipses can provide information about Earth’s motion, such records are important tools for understanding Earth’s movement throughout history. According to scientists, our ancestors recorded astronomical events without taking into account the important information that astronomers need today, so it is often difficult to determine the correct time, place and duration of historical eclipses.

“Although the original eyewitness accounts of this period are mostly lost, quotations, translations, etc., recorded by later generations contain valuable information. “In addition to reliable location and time information, we need confirmation of a total eclipse – the daytime darkness was so dark that stars appeared in the sky,” said Koji Murata, associate professor at the University of Tsukuba in Japan.

The team identified five total solar eclipses recorded in the eastern Mediterranean region in the years 346, 418, 484, 601 and 693. As an example of the impact of this new research, an eclipse was recorded on July 19, 418, when the sky was so total that the stars were visible. The place to observe this solar eclipse was Constantinople, then the capital of the Roman Empire, and now Istanbul in modern Turkey.

An earlier model of delta-T (ΔT is the length of an Earth day) predicted that Constantinople was outside the path of totality, the region where observers would see the Moon completely cover the Sun for this particular eclipse. Therefore, this ancient description of the total eclipse means that the fifth century ΔT must be adjusted. Other recently discovered accounts require adjustments to ΔT models in later centuries.

“Our new ΔT data fill an important gap and indicate that the ΔT margin in the 5th century should be revised upward, while it should be revised downward in the 6th and 7th centuries,” Murata said.

Updated details of Earth’s rotation will help scientists study other global phenomena throughout history, including changes in sea level and the amount of ice on the planet.

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