Who is Aristarch of Samos?

Who is Aristarch of Samos?

December 13, 2020 Off By Felso

Aristarcus is a Greek astronomer and mathematician who lived between 310 BC and 230 BC.

He was born on the island of Samos. He was one of the first known advocates of the heliocentric belief that puts the Sun in the center of the universe, not the Earth. Influenced by Pythagoras and Filolaos. Although Aristarch, like Philolaos, put the Sun in the center, he had different views from Philolaos in terms of the order of the planets. His astronomical ideas did not prevail over the geocentric theories of Aristotle and Ptolemy, which were valid for 1800 years, until the discoveries of Copernicus, Kepler, and Newton. Aristarcus Crater on the Moon is also named after him.

It is known that Aristarkhos was a student of Straton from Lampsakos (Lapseki) in Lykeion, founded by Aristotle in Athens, and Straton was appointed as the head of this school in 288 BC. Straton, who tried to reconcile Aristotle’s philosophy with natural sciences and gave physics a privileged place among other sciences, greatly influenced Aristarch’s view of science.

Aristarch, who made the first observations on the “summer tropics”, in which the Sun turns from the northern hemisphere to the southern hemisphere during the apparent annual motion of the Sun in 281-280 BC, was also a valuable mathematics scholar. In his study entitled “On the Dimensions and Distances of the Sun and the Moon”, which has survived until today, he calculated the numerical values ​​of these celestial bodies with eighteen propositions he built on six hypotheses using Eukleides geometry. Although his conclusions with trigonometric proportions are wrong, his approach and method are correct; Moreover, it is an important step in understanding the dimensions of the universe. Aristarch also made corrections on the solar year and lunar-day cycles calculated by Meton, Eudoksos and Kallippos, designed a sundial that was more developed than the known examples, and studied light, colors and vision phenomena.

Aristarch’s greatest contribution to astronomy was that he paved the way for the recognition of the universe and the solar system, if not beyond an assumption. Aristarchus was the first astronomer who prepared the birth of the heliocentric system to be developed by Copernicus in the 16th century by making the assumption that the celestial body located in the center of the universe was the Sun, not the Earth. Until Aristarch, who was called the “Copernicus of the Ancient Age”, the geocentric system initiated by Pythagoras in the 6th century BC was adopted by all astronomers and thinkers for about two centuries. In the 5th and 4th centuries BC Eudoksos, Kallippos (c. 370-330 BC) and Aristotle developed this theory and explained the motion of the Sun, Moon and planets with concentric spheres orbiting the stationary Earth. Herakleides, known as the greatest astronomer of the Aristotelian period (the second half of the 4th century BC), on the other hand, said that the inner planets such as Venus and Mercury were around the Sun, not the Earth; He argued that the sun, moon and exoplanets also orbit the earth, the center of the whole system. Also, in the Ancient Age, no one supported this “geocentric” universe model of Herakleides, who claimed that the Earth rotates around its own axis. In contrast, it can be said that Aristarch was heavily influenced by Heracleides.

Since only a small study of Aristarch has survived, his heliocentric theory and other works are known, especially as Plutarch quotes. According to these sources, the sphere of stars conceived by Aristarchus is actually stationary; The earth and the other planets orbit in circular orbits around the immobile Sun at the center of this stellar sphere. Aristarch, explaining the apparent daily motion of the stars as the Earth rotates around its own axis, attributed the fact that the stars still seem static against the annual rotation of the Earth around the Sun, to the fact that the sphere of stars is incomparably larger than the sphere containing the Earth’s orbit.

During this period when Aristotelian physics and Plato thought were dominant, Aristarch’s theory was criticized harshly on the grounds that it was against the knowledge of physics and astronomy. Aristarch was accused of atheism. This assumption, supported only by one of his students, Seleucus, was completely forgotten in the 2nd century IIS, with the view supported by the church circles of Ptolemy, who argued that the Earth was motionless and was at the center of the universe. At the beginning of the 16th century, when Copernicus brought the heliocentric system back to the agenda, the foundations of Aristotelian physics had begun to collapse and the science of mechanics had developed a little more. Hence the heliocentric system being known by the name of Copernicus. It can be explained by the achievement of the sciences as well as the success of Copernicus. It is known that Copernicus knew Aristarch’s heliocentric theory and even wrote it to add to a work, but did not use this information in the printed text.

Prepared by: Sociologist Ömer YILDIRIM
Source: Ömer YILDIRIM’s Personal Lecture Notes. Atatürk University Department of Sociology First Class