quote:
The earliest traces of a counter-intuitive idea that it is the Earth that is actually moving and the Sun that is at the centre of the solar system (hence the concept of heliocentrism) is found in several Vedic Sanskrit texts written in ancient India. Yajnavalkya (c. 9th–8th century BC) recognized that the Earth is spherical and believed that the Sun was "the centre of the spheres" as described in the Vedas at the time. In his astronomical text Shatapatha Brahmana (8.7.3.10) he states: "The sun strings these worlds - the earth, the planets, the atmosphere - to himself on a thread." He recognized that the Sun was much larger than the Earth, which would have influenced this early heliocentric concept. He also accurately measured the relative distances of the Sun and the Moon from the Earth as 108 times the diameters of these heavenly bodies, close to the modern measurements of 107.6 for the Sun and 110.6 for the Moon. The calendar he described in the Shatapatha Brahmana corresponds to an average tropical year of 365.2467 days, which was only 6 minutes longer than the modern value of 365.2422 days.
The Vedic Sanskrit text Aitareya Brahmana (2.7) (c. 9th–8th century BC) also states: "The Sun never sets nor rises. When people think the sun is setting, it is not so; they are mistaken." This indicates that the Sun is stationary (hence the Earth is moving around it), which is elaborated in a later commentary Vishnu Purana (2.8) (c. 1st century), which states: "The sun is stationed for all time, in the middle of the day. [...] Of the sun, which is always in one and the same place, there is neither setting nor rising."
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Heraclides of Pontus (IV century BC) explained the apparent daily motion of the celestial sphere through the rotation of the Earth, and probably realized also that Mercury and Venus rotate around the Sun. The first to propose the heliocentric system however, was Aristarchus of Samos (c. 270 BC). Unfortunately his writings on the heliocentric system are lost, but we have other authors who give us crucial information about his system (the most important among them is Archimedes, who lived in the third century BC and therefore had direct knowledge of Aristarchus's works). By the time Aristarchus was writing, the size of the Earth had been calculated accurately by Eratosthenes. Aristarchus also calculated the size of the earth, and measured the size and distance of the Moon and Sun, in a treatise which fortunately survived. His geometrical method is exact, but it requires the difficult measurement of the angle between the Sun and the Moon when the latter is at the first or last quarter, which is slightly less than 90 degrees. Aristarchus overestimated the angle and consequently underestimated the distance and size of the Sun (although his figures for the Moon are fairly good). What is important, however, is Aristarchus's scientific approach, and his result that the Sun is much larger than the Earth. Perhaps, as many people have suggested, paying attention to these numbers led Aristarchus to think that it made more sense for the Earth to be moving than for the huge Sun to be moving around it.
Verbazingwekkend.