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Aristarchus

The first of the Greek philosphers and mathematicians to unravel the celestial plan and announce the discovery was Aristarchus of the isle of Samos. Others before him assumed that the Earth is a sphere and that it moves, but he was the first to formulate plainly the heliocentric theory, the scheme which has the Sun in the center.

Aristarchus lived from about the year 310 before the present era to about 230, and among the geometers he succeeded Euclid and preceded Archimedes. In -288 or -287 he followed Theophrastus as the head of the Peripatetic School established by Aristotle.

Aristarchus’ only extant treatise is “On the Sizes and Distances of the Sun and Moon.” In it he calculated the diameter of the Sun as about seven times the diameter of the Earth, thus estimating the Sun’s volume as about 300 times the volume of the Earth (the actual diameter of the Sun is about 300 times the diameter of the Earth; the solar volume is equal to 1,300,000 volumes of the Earth). In this work of Aristarchus there is nothing indicating his heliocentric theory. It was probably this his realization of the superior mass of the Sun that brought him to his discovery. Or should a celestial body three hundred times larger than the Earth revolve around it each day?

Aristarchus’ book on the planetary system with the Sun in the center did not survive, and we know of it only through references to its content, chiefly by Archimedes. Archimedes, who was twenty-five years his junior, wrote: “Aristarchus brought out a book consisting of certain hypotheses. . . . His hypotheses are that the fixed stars and the Sun remain unmoved, and that the Earth revolves about the Sun in the circumference of a circle, the Sun lying in the middle of the orbit.” He also added that according to Aristarchus who is in contradiction to “the common account” of astronomers, the universe is many times larger than generally assumed by astronomers, and the fixed stars are at an enormous distance from the Sun and its planets.(1) Aristarchus regarded the Sun as one of the fixed stars, the closest to the Earth. “Aristarchus sets the Sun among the fixed stars and holds that the Earth moves round the sun’s circle (i.e., ecliptic)” referred another author, centuries later.(2)

As Archimedes said, the view of Aristarchus conflicted with the common teaching of the astronomers, and he also quoted it only to put it aside disapprovingly. One of the contemporaries of Aristarchus, Cleanthes, wrote a treatise “Against Aristarchus.” (3) Whatever his scientific argument may have been, he accused Aristarchus of an act of impiety. Plutarch wrote in his book Of the Face in the Disc of the Moon (De facie in orbe lunae) that Cleanthes “thought it was the duty of the Greeks to indict Aristarchus of Samos on the charge of impiety for putting in motion the Hearth of the Universe, this being the effect of his attempt to save the phenomena by supposing heaven to remain at rest and the Earth to revolve in an oblique circle, while it rotates, at the same time, about its own axis.” (4)

We do not know whether there was any actual court action and verdict; however, we know that a verdict of judges, even if unanimous, could not make the Sun a satellite of the Earth. Not even a scientific tribunal can do this, not even if it is presided over by Archimedes and the most illustrious men of the generation sit as judges.

The spokesman of the scholarly world was Dercyllides, who announced that “we must assert the Earth, the Hearth of the house of the Gods, according to Plato, to remain fixed, and the planets with the whole embracing heaven to move and reject the view of those who brought to rest the things which move and set in motion the things which by their nature and position are unmoved, such a supposition being contrary to the theories of mathematicians.(5)

Aristarchus had no followers in his generation, nor in the next generation. About a century after Aristarchus, Seleucus, a Chaldean of Seleucia on the Tigris, who lived and wrote about the year 150 before the present era, adopted the teaching of Aristarchus.

Hipparchus was a contemporary of Seleucus. Hipparchus is thought to be the greatest astronomer of antiquity, and even today there are worshippers of his among the menbers of the faculties. But he rejected the heliocentric system of Aristarchus, and this he did not on a religious ground, but on a scientific one. A system with the Sun in the center of circular orbits could not account for the peculiarities in the visible motions of the planets, but the theory of epicycles could, and this theory had the Earth immobile in the center of the universe.

Thus the religious dogma and the mathematical analysis, both, condemned Aristarchus and his teaching that the Earth circles around the Sun.


References

1.

Archimedes, ed. Heiberg, vol. II, p. 244 (Arenarius I. 4-7); The Works of Archimedes, ed. Heath, pp. 221-222. See Heath, Aristarchus of Samos, (Oxford University Press, 1913) p. 302.
2.

Aetius (ii.24.8) Dox. Graec. p. 355.19 Bekker. See Heath, Aristarchus of Samos, p. 305.
3.

Diogenes Laertius, Lives of the Famous Philosophers, mentions such a tract among the works of Cleanthes. Cf. Th. Heath, Aristarchus of Samos (Oxford, 1913), p. 304.
4.

De facie in orbe lunae ch. 6, pp. 922F-923A; cf. Heath, Aristarchus of Samos, p. 304.
5.

Theon of Smyrna (ed. Hiller) p. 200, 7-12. Cf. Heath, Aristarchus of Samos, p. 304.


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