According to a controversial new study the world's oldest star map, known as the Star Manual of Master Shi, was created in China over two thousand three hundred years ago, dating back to 355 BCE. The discovery pushes back the origin of the star map by two hundred fifty years earlier than previously believed, resolving decades of debate about its true age and origin. Researchers at the National Astronomical Observatories of China analyzed the ancient manuscript using image-processing techniques, including the Generalized Hough Transform algorithm and artificial-intelligence technology. By comparing the positions of stars recorded in the map with modern coordinates, they determined that the map dates back to the fourth century BCE, the same period during which Master Shi Shen is believed to have lived. “Ancient astronomical observation is a valuable cultural heritage, profoundly influencing both the fields of culture and modern scientific research,” the researchers assert. Their study attributes previous contradictions in the dating of Shi's star catalog to copying errors and partial updates that occurred over the centuries as the manuscript was modified—sometimes inaccurately—after hundreds of years.
The Star Manual of Master Shi records the detailed positions of one hundred twenty stars, of which one hundred eighteen have complete data. Experts believe that the author applied a spherical coordinate system, possibly related to the invention of the armillary sphere, a celestial-navigation instrument invented in ancient China. This structured format distinguishes it from earlier Babylonian records, which are written descriptions rather than catalogs that number the stars and depict the night sky. Although Babylonian records mentioning star positions predate ancient Chinese and Greek astronomers, the structured and systematic approach of Shi's star catalog sets it apart. The new dating indicates that it predates the star map created by the ancient Greek astronomer Hipparchus by more than two hundred years, making it the oldest known star catalog of its kind in the world.
“I think this result is absolutely conclusive,” said David Pankenier, Emeritus Professor of Chinese Astronomy at Lehigh University in Pennsylvania. He stated that the study confirms previous research, particularly the work of Joseph Needham, a British biochemist known for his expertise in ancient Chinese science and technology. Historians and astronomers have long been puzzled by the alleged contradictions in the dates of Shi's star catalog. Some measurements in the catalog appear to be hundreds of years older than others. Some experts not involved in the study suggest that the contradictions exist because the original instrument used to create the guide was off by one degree.
“The claim of possessing the oldest star map—or any other scientific instrument—has been a source of national pride for the past three hundred years,” said Daniel Morgan, a historian specializing in early Chinese astronomy, mathematics, and measurement at the French Center for Research on East Asian Civilizations. He added that colonialism, along with decades of European centrism, created a kind of “competition between civilizations,” where nations feel the need to prove themselves. The political importance of establishing the oldest star map is not lost among nations, as many civilizations such as Babylon, China, and regions of South America all want to claim a pioneering position in cosmic observation. According to Archaeology Magazine, this desire to establish primacy in astronomical history underscores the importance of such discoveries.
The researchers used modern digital-image-processing techniques and a type of artificial intelligence known as computer vision to discover errors between similar images of the star map. By analyzing these discrepancies, they were able to date the origin of the manuscript more accurately. Scientists can determine the date of star maps because constellations appear to shift over hundreds of years due to the precession of Earth's axis. This gradual movement causes the stars' positions to change slightly over time, allowing researchers to pinpoint when observations were made based on the recorded positions.
The Star Manual of Master Shi was initially believed to have been created around 125 CE but is now determined to have been recorded in the fourth century BCE and later revised in the second century CE, sometimes inaccurately. Experts believe that this ancient star map not only provides insights into the astronomical knowledge of ancient China but also demonstrates the sophistication of their observational techniques. The application of a spherical coordinate system and the possible use of the armillary sphere indicate the scientific capabilities of the period.
The article was written with the assistance of a news analysis system.