The discussion revolves around the recent discovery of a medieval manuscript that may contain part of the long-lost star catalogue of the ancient astronomer Hipparchus. Participants explore the implications of this find for understanding ancient astronomy, the motivations behind such investigations, and the historical context of astronomical knowledge, including the concept of precession.
Participants express a range of views regarding the knowledge of precession in ancient cultures, with some asserting that evidence is lacking while others believe that ancient astronomers had some awareness of celestial changes. The motivations behind astronomical investigations also prompt varied interpretations.
Limitations include the uncertainty surrounding the extent of ancient astronomical knowledge and the potential loss of historical records due to wars and cultural dismissiveness. The discussion reflects differing interpretations of the evidence and the motivations of ancient astronomers.
https://www.scientificamerican.com/...night-sky-found-hidden-in-medieval-parchment/A medieval parchment from a monastery in Egypt has yielded a surprising treasure. Hidden beneath Christian texts, scholars have discovered what seems to be part of the long-lost star catalogue of the astronomer Hipparchus—believed to be the earliest known attempt to map the entire sky.
Scholars have been searching for Hipparchus’s catalogue for centuries. James Evans, a historian of astronomy at the University of Puget Sound in Tacoma, Washington, describes the find as “rare” and “remarkable”. The extract is published online this week in the Journal for the History of Astronomy. Evans says it proves that Hipparchus, often considered the greatest astronomer of ancient Greece, really did map the heavens centuries before other known attempts. It also illuminates a crucial moment in the birth of science, when astronomers shifted from simply describing the patterns they saw in the sky to measuring and predicting them.
The manuscript came from the Greek Orthodox St Catherine’s Monastery in the Sinai Peninsula, Egypt, but most of its 146 leaves, or folios, are now owned by the Museum of the Bible in Washington DC. The pages contain the Codex Climaci Rescriptus, a collection of Syriac texts written in the tenth or eleventh centuries. But the codex is a palimpsest: parchment that was scraped clean of older text by the scribe so that it could be reused.
Nine folios revealed astronomical material, which (according to radiocarbon dating and the style of the writing) was probably transcribed in the fifth or sixth centuries. It includes star-origin myths by Eratosthenes and parts of a famous third-century-BC poem called Phaenomena, which describes the constellations. Then, while poring over the images during a Coronavirus lockdown, Williams noticed something much more unusual.
Several lines of evidence point to Hipparchus as the source, beginning with the idiosyncratic way in which some of the data are expressed. And, crucially, the precision of the ancient astronomer’s measurements enabled the team to date the observations. The phenomenon of precession—in which Earth slowly wobbles on its axis by around one degree every 72 years—means that the position of the ‘fixed’ stars slowly shifts in the sky. The researchers were able to use this to check when the ancient astronomer must have made his observations, and found that the coordinates fit roughly 129 BC—during the time when Hipparchus was working.
Babylonian astronomers had previously measured the positions of some stars around the zodiac, the constellations that lie along the ecliptic—the Sun’s annual path against the fixed stars, as seen from Earth. But Hipparchus was the first to define the locations of stars using two coordinates, and to map stars across the whole sky. Among other things, it was Hipparchus himself who first discovered Earth’s precession, and he modeled the apparent motions of the Sun and Moon.
I believe that the Egyptians knew about precession. They had several millennia worth of data, which would make it obvious. But they kept it a religious secret and did not publish.Astronuc said:https://www.scientificamerican.com/...night-sky-found-hidden-in-medieval-parchment/Hipparchus worked on the Greek island of Rhodes three centuries before, roughly between 190 and 120 BC, astronomer Claudius Ptolemy in Alexandria, Egypt compiled a star catalogue.
https://en.wikipedia.org/wiki/Hipparchus
https://arxiv.org/ftp/physics/papers/0407/0407108.pdfAll in all, there is no clear, absolute evidence of discovering of precession before Hellenistic times or in pre-Columbian cultures.
There is, however, at least in my view, a clear evidence that some astronomical phenomena, such as the heliacal rising of bright stars or the movement of the equinoctial point trough the constellations, were traced for a sufficient amount of time and with a sufficient precision to lead many ancient astronomers to the discovery that “something was happening” with a very slow velocity with respect to human life.
Same reason I took apart every toy I ever got. Just a guess.Lnewqban said:I have always wondered what the driving motivation for such deep investigations was for people like Hipparchus, back at that time.