Latest news with #Hipparchus
Gizmodo
24-05-2025
- Science
- Gizmodo
Researchers Claim Ancient Chinese Star Catalog Is the Oldest of Its Kind—But Not Everyone's Convinced
Humans have been stargazing for thousands—possibly hundreds of thousands of years. Ancient people around the globe looked to the heavens for physical and spiritual guidance. Dozens and dozens of generations later, their descendants are now arguing over which civilization created the oldest known visual star catalog in the world. Researchers from the Chinese Academy of Sciences' National Astronomical Observatories claim that Shi's Star Catalog, the oldest known star catalog in China, is actually the earliest known star catalog, period. They reached this conclusion using a technique that accounts for potential human errors made thousands of years ago. If their results prove to be true, it would mean that Shi's Star Catalog is centuries older than the other first place contender—the one created by Greek astronomer Hipparchus. But not everyone in the scientific community is convinced. 'In comparison to the observation epochs of other ancient star catalogs worldwide, the Shi's Star Catalog predates even the oldest Western star catalogs, affirming its status as the oldest star catalog in the world,' the researchers wrote in a study posted to the preprint server arXiv in April. Because Earth's axis wobbles, the location of stars in the night sky changes over the centuries in a phenomenon called precession. Researchers can use Earth's precession to date ancient visual star catalogs by calculating the difference between historical records of the night sky and what our stars look like now. Shi's Star Catalog, however, has been infamously difficult to date, not least because this one catalog depicts star positions that seem to span multiple centuries. In the preprint study, the researchers outline a number of previously suggested dates: around 360 BCE; around 360 BCE with an update around 200 CE; around 440 BCE with an update around 160 CE; sometime between 100 BCE and 70 BCE; and during the seventh century CE. 'A multitude of perspectives exist regarding the observational timeframe of the Shi's Star Catalog, with no definitive consensus reached,' the researchers admitted. As such, they decided to analyze the catalog's 120 stars with the Generalized Hough Transform method—an algorithmic imaging technique that 'statistically accommodates errors in ancient coordinates and discrepancies between ancient and modern stars, addressing limitations in prior methods,' they explained. This approach seems to confirm that Shi's Star Catalog was first drafted around 355 BCE and then updated around 125 CE. 'In comparison, the Western tradition's oldest known catalog, the Ptolemaic Star Catalog (2nd century CE), likely derives from the Hipparchus Star Catalog (2nd century BCE). Thus, Shi's Star Catalog is identified as the world's oldest known star catalog,' they added. Some scientists, however, have a different theory: The instrument used to record Shi's Star Catalog was off by one degree. Previous studies adjusting for this assumption date Shi's Star Catalog around or after 103 BCE, as reported by Science. Certain historians look favorably on this later date because it aligns the catalog's use of spherical coordinates more closely with the Chinese invention of the armillary sphere (a spherical mathematical instrument used to track the movement of celestial bodies around Earth) and their adoption of a spherical cosmological model, both of which took place in the first century BCE, according to Science. Suggesting that people used spherical coordinates hundreds of years before the invention of the armillary sphere, as the researchers do in the recent study, would be like finding 'a receipt from a gas station and somebody wants to say it's from 1700,' Daniel Patrick Morgan, a historian at France's Center for Research on East Asian Civilizations who was not involved with the study, told Science. Future research may provide more answers. Whether or not the recent study proves to be true, it's worth noting that the Western world's Eurocentric approach has historically undervalued achievements made elsewhere, including those in ancient China. Plus, the ancient Babylonian seventh century BCE Astronomical Diaries blow both European and Asian astronomical artifacts out of the water, even though the tablets list astronomical observations via text, not visuals.
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?
South China Morning Post
05-05-2025
- Science
- South China Morning Post
Is ancient Chinese astronomer Shi Shen's stellar catalogue the world's first star log?
Two Chinese scientists believe their country's earliest star catalogue – an astronomical list of celestial bodies known as 'Shi's Star Catalogue' – is the world's oldest star log, dating back some 2,400 years. Advertisement Citing new evidence in a study published on April 4 in the peer-reviewed astronomy journal Research in Astronomy and Astrophysics, researchers Zhao Yongheng and He Boliang from the National Astronomical Observatories, under the Chinese Academy of Sciences, said that Shi's Star Catalogue was created around 335BC. That would make the stellar accounts , also known as the Star Manual of Master Shi, the oldest known human records of the stars, according to the study. In their investigation, the astronomers used image processing technology to convert ancient records into measurable celestial coordinates, which ultimately confirmed approximate years of observations in the main content of Shi's Star Catalogue, which was followed by supplementary revisions centuries later, around AD125. Experts believe that astronomers from both China and Greece began studying the night sky in detail at around the same time. Advertisement Until now, the Hipparchus star catalogue from Greece has been recognised as the world's oldest, believed to have been created in the 2nd century BC. But the new research published by Zhao and He suggests that the Chinese catalogue is the oldest known human record of the stars.
