Ancient Chinese writings are providing fresh insight into what may be the earliest known description of a solar eclipse and possibly the first written record of the Sun’s corona. According to researcher Hayakawa, the centuries-old text contains a surprising observation that is consistent with what modern astronomers recognize as the solar corona, the Sun’s glowing outer atmosphere visible only when the Moon completely blocks its light. “If this interpretation is accurate, it represents one of the oldest surviving accounts of the solar corona,” he said.

To verify the ancient report, the research team first attempted to model the Earth’s rotation at the time the eclipse occurred. However, their initial simulations suggested that the event would not be visible from Qufu, the capital of Lü Duchy, where the historical chronicles were originally compiled. That confusion prompted a closer look at the archaeological and geographical records.

The researchers realized that earlier studies had relied on coordinates located about 8 kilometers (about 4. 79 miles) away from the actual location of the ancient capital. Once conditions are in place, the team can more accurately estimate Earth’s rotation during the eclipse, determine the tilt of the Sun’s rotation axis, and recreate how the corona might have appeared during the event.

The refined dataset corrects long-standing inaccuracies in previous reconstructions of historical astronomical events, he says. “This work improves the accuracy of dating and modeling of past eclipses and Earth’s rotation,” said co-author Mitsuru Soma of the National Astronomical Observatory of Japan.