Latest news with #ChineseNationalAstronomicalObservatories
Yahoo
22-05-2025
- Science
- Yahoo
Scientists Identified the Oldest Star Chart In Existence, Written 2,300 Years Ago.
Ancient Chinese astronomer Shi Shen's star catalog, known as The Star Manual of Master Shi, is now considered the oldest star chart in the world. Later observations written into the catalog showed inconsistencies with Shi's findings. This was because of Earth's shift on its axis, or precession, which was corrected by an AI algorithm. This catalog predates the second oldest chart—compiled by ancient Greek astronomer Hipparchus—by several hundred years. When astronomer and astrologer Shi Shen gazed skyward thousands of years ago, he beheld what must have looked like another realm glittering in the heavens. Constellations were seen by the ancient Chinese as palaces or celestial mansions. The imperial court of advisers, princes, and concubines were mirrored in individual stars. In the event of a solar eclipse, a dragon swallowed the Sun. Shi—who lived during the tumultuous Zhanguo or Warring States period—mapped the coordinates of 120 stars ranging from the Supreme Palace Enclosure of the Virgo, Coma Berenices, and Leo constellations to Polaris (the North Star), which represented the emperor himself. Eventually, the Star Manual of Master Shi, or Shi Shi Xing Jing, became a meticulous record of his observations. For centuries, despite this document being the oldest surviving catalog of stars in China, the star catalog of ancient Greek astronomer Hipparchus (dated to 130 B.C.) was thought to be older. But ancient and modern worlds collided when a team of researchers at the Chinese National Astronomical Observatories (NAO)—led by Boliang He and Yongheng Zhao—used AI to date Shi's catalog to the 4th century B.C. That makes it 200 years older than the Hipparchus catalog, and the earliest known surviving catalog of stars. 'Based on the records of precession and retrograde precession, it is inferred that the Shi's Star Catalog approximately corresponds to the Zhanguo period, around 360 B.C.,' the researchers said in their study, which is awaiting peer review and has been uploaded to the preprint server arXiv. Earth rotates on an axis that slowly shifts position—the gravity of the Sun and Moon pulling at the planet and causing tidal forces that create a bulge at the equator results in changes to the Earth's rotation over time. This phenomenon is known as axial precession, and it affects how stars are observed from terra firma. Ancient celestial coordinates, as a result, eventually become outdated. When updates were made to Shi Shi Xing Jing by Han Dynasty astronomer Zhang Heng sometime around 125 A.D., axial precession meant that star positions were inconsistent with Shi's original catalog. To prove that precession was the reason for these inconsistencies, He, Zhao, and their team used an AI algorithm based on the Hough Transform, which can isolate features of shapes in an image, so long as those shapes are specified. Their version of the algorithm was designed to measure the difference in stellar positions due to precession. It ruled out errors made by later astronomers who copied coordinates (since the manuscript changed hands many times), and used statistics to estimate where the North Star—and therefore the stars surrounding it—must have been in relation to Earth at the time Shi mapped them. The results dated more recent observations to the 2nd Century A.D., but the oldest traced back to Shi's epoch. Still, there is some controversy over the findings, with skeptics such as historian Bosun Yang (from the University of Science and Technology of China) and Ziaochun Sun (from the Chinese Academy of Sciences) arguing that the spherical measurements suggests the use of an armillary sphere—an ancient Chinese invention used to measure the positions of stars. The armillary sphere did not yet exist when Shi was mapping celestial objects. If Shi used another instrument that had been misaligned, Yang and others found that would push the catalog to about 103 B.C.—still older than Hipparchus. Zhao and He still insist that their findings are accurate, and plan to investigate more of Shi's observations. '[Our method] effectively mitigates the error issues encountered in previous methodologies, thus reliably resolving the challenge of determining the observation epochs of ancient Chinese stars,' they said. 'The Shi's Star Catalog predates even the oldest Western star catalogs, affirming its status as the oldest star catalog in the world.' You Might Also Like The Do's and Don'ts of Using Painter's Tape The Best Portable BBQ Grills for Cooking Anywhere Can a Smart Watch Prolong Your Life?
Yahoo
16-05-2025
- Science
- Yahoo
World's oldest star chart may be 2,300 years old and from China — but not everyone agrees
When you buy through links on our articles, Future and its syndication partners may earn a commission. The oldest star chart in the world was made in China more than 2,300 years ago, a hotly debated preprint study finds. Researchers at the Chinese National Astronomical Observatories analyzed the "Star Manual of Master Shi," the oldest surviving star catalog in China, using a novel digital image processing technique. The method, called Generalized Hough Transform, uses a type of artificial intelligence known as computer vision to find and mitigate significant errors between similar images. They found that the ancient star chart actually dates to 355 B.C. — 250 years earlier than previously thought — and that it was later updated around A.D. 125. This would make it the oldest-known star catalog of its kind in the world, predating a star chart by ancient Greek astronomer Hipparchus by more than 200 years. "I think this is pretty definitive,"said David Pankenier, a professor emeritus of Chinese astronomy at Lehigh University in Pennsylvania who was not involved with the research. Pankenier told Live Science that the study confirms previous research — notably, the work of Joseph Needham, a British biochemist known for his expertise on ancient Chinese science and technology. And the new study places the manuscript's origin around the same time the historical Master Shi Shen was thought to have lived. But other experts are less convinced. Related: World's oldest complete star map, lost for millennia, found inside medieval manuscript Historians and astronomers have long been puzzled by the alleged date discrepancies in Shi's star catalog, in which some measurements seem to be hundreds of years older than others. Scientists can date star charts because, from Earth's perspective, constellations appear to drift over hundreds of years because of the wobble in our planet's axis. Stars also have their own motion, which means that different centuries will have different-looking maps of the night sky. The new study chalks this discrepancy up to copying errors and partial updates, claiming that the manuscript was first created in the fourth century B.C. and then amended — sometimes inaccurately — hundreds of years later. However, some experts not involved with the study instead suggest that the discrepancies exist because the original instrument used to create the manual was off by a factor of one degree. Applying this interpretation brings the two seemingly conflicting sets of dates back into harmony and places the manuscript's origin at around 103 B.C., Daniel Morgan, a historian who specializes in early Chinese astronomy, mathematics and metrology at France's Center for Research on East Asian Civilizations, told Live Science. This reasoning also helps explain why the catalog uses a spherical coordinate system, which Chinese astronomers adopted after inventing the armillary sphere — a device consisting of interlocking rings representing things like constellations' paths and latitude and longitude lines — in the first century B.C. "It just so happens that if you take this really anodyne consideration into account — that maybe they built an instrument and it was not perfect — then the astronomers' data analysis perfectly aligns with the human story," Morgan said. He pointed out that laying claim to the oldest star chart (or any other scientific tool) has become a source of national bragging rights over the last 300 years. Colonialism combined with decades of Eurocentrism have created a kind of "inter-civilizational … competition" whereby nations feel the need to prove themselves, he said. RELATED STORIES —Are 3,000-year-old carvings from Italy a star map? Researchers can't agree. —Mysterious Antikythera Mechanism may have jammed constantly, like a modern printer. Was it just a janky toy? —World's oldest calendar found at 13,000-year-old temple in Turkey But that same sense of national pride may have kept Western researchers from taking ancient Chinese astronomers seriously even as recently as 100 years ago, Pankenier said. Early 20th-century analyses of Chinese star charts by Europeans were dismissive of what they saw as inferior technology, even though many of these records proved highly accurate. But regardless of whether scientists deem the Chinese or the Greek star catalogs as older, Babylonian records that mention star positions far outstrip both ancient Chinese and Greek astronomers, as they date to the eighth century B.C. However, these records are written descriptions and are not catalogs that number the stars and portray the night sky. The preprint is currently under review at the journal Research in Astronomy and Astrophysics.
