The origin of total solar eclipses has long remained mysterious before the Moon was identified as the only culprit. They belonged to the repertoire of mythology … then the sciences gradually took over.
On August 21, 2017, the Americans have experienced a total solar eclipse. The phenomenon is now well known thanks to the work of astrophysicists over the last centuries, but it has not always been the same in the history of mankind. Confronted with the unexpected disappearance of the Sun in broad daylight, the different past cultures sought to give meaning to this phenomenon, seeing the intervention of a divinity, a demon or sometimes even a malicious genius. It took some time before the real culprit, the Moon, was identified. Retrospective.
For a long time, eclipses have been „seen as bad omens,“ says Robert Massey of the Royal Astronomical Society UK. In China, the offender was considered to be a heavenly dragon that devoured the Sun. People tried to chase him away by making noise, notably by striking on drums or various objects. In Korea or the Vikings it was believed that dogs are trying to steal the sun star.
„It took the observations of the astronomers and the study of the motion of the Sun and that of its natural satellite, to understand that it is the Moon which at each eclipse interposes before the Sun“ , underlines Pascal Descamps, astronomer at The Institute of Celestial Mechanics and Calculation of Ephemerides (IMCCE) in Paris.
Eclipses have been a subject of observations for millennia. From 700 BC and up to 50 BC The Babylonians methodically consigned them to the tablets. The Chinese also watched closely this phenomenon, considered very important for the Emperor. What about those who failed in their predictions? In 2137 BCE, two court astronomers, Hi and Ho brothers, had their heads cut off for failing to predict the eclipse.
The Greek historian Herodotus relates that Thales of Miletus would have been able to predict an eclipse in 585 BC. The eclipse would have occurred during a battle between the Lydians and the Medes, after which the belligerents would then have laid down their arms, seeing there an injunction of the gods to cease the fight. A thesis contested by contemporary astronomers, but which has marked History.
In the second century of our era the Greek Ptolemy created his great treatise on astronomy and it is the first time the precise knowledge of the different parameters necessary to predict an eclipse was acquired, sais Pascal Descamps.
„In the Renaissance, and most certainly thanks to the invention of the telescope (circa 1600) and Copernicus’ work, the total solar eclipses were no longer considered as a particularly frightening event“, Considers Robert Massey. The Polish monk Copernicus (1473-1543) indeed theorized that the Earth revolves around the Sun, not the reverse as Aristotle thought. And some 300 years ago Britain’s Edmond Halley drew up a map describing almost exactly the trajectory of the shadow induced by the total solar eclipse over England in May 1715.
The triumph of rationalism
Nowadays, scientists know how to predict eclipses with extreme precision (less than a second). “ Thus, eclipses can be seen as a celebration of rationalism“, notes the European Space Agency (ESA) on its website. However, certain beliefs have a hard life and are resistant to scientific explanations, pointed for its part the American space agency (NASA) on its site. Nasa thus draws up a list of „false ideas“ around eclipses. Among them is the fact that pregnant women should not watch the show because it can hurt the baby, or that food prepared during an eclipse can be poisoned by the radiation that escapes from the solar corona. So many claims without scientific basis.