Aristarchos of Samos (Ἀρίσταρχος) was a Greek astronomer and mathematician born on the
island of Samos, in , he succeeded Theophrastus as head of the Peripatetic school in 288 or 287 B.C and held the position for approximately 18 years, he was the pupil of Strato of Lampsacus in Alexandria of Egypt where he studied just few years before the start of the kingdom of Ptolemy II Philadelphus. Greece
Statue of Aristharcos from the Aristotlr Univerity in
Aristarchos was the first known astronomer to put forward the heliocentric hypothesis as documented by the available ancient sources: the first and closest witness in time was Archimedes who was a younger contemporary of Aristarchus. Archimedes wrote:
"You (King Gelon) are aware the 'universe' is the name given by most astronomers to the sphere the center of which is the center of the Earth, while its radius is equal to the straight line between the center of the Sun and the center of the Earth. This is the common account as you have heard from astronomers. But Aristarchus has brought out a book consisting of certain hypotheses, wherein it appears, as a consequence of the assumptions made, that the universe is many times greater than the 'universe' just mentioned. His hypotheses are that the fixed stars and the Sun remain unmoved, that the Earth revolves about the Sun on the circumference of a circle, the Sun lying in the middle of the Floor, and that the sphere of the fixed stars, situated about the same center as the Sun, is so great that the circle in which he supposes the Earth to revolve bears such a proportion to the distance of the fixed stars as the center of the sphere bears to its surface"
The heliocentric hypothesis is here stated in language which leaves no room for doubt about its meaning.
Copernicus himself admitted that the theory was attributed to Aristarchus, though this does not seem to be generally known. Copernicus refers in two passages of his work, De revolutionibus caelestibus, to the opinions of the ancients about the motion of the earth. Copernicus did mention the theory of Aristarchus in a passage which he afterwards suppressed :
'' Credibile est hisce similibusque causis Philolaum mobilitatem terrae sensisse, quod etiam nonnuli Aristarchum Samium ferunt in eadem fuisse sententia ".
I am attaching a link to download a digital copy of “Aristarchos of Samos: the Copernicus of Antiquity” by Sir Thomas Heath ( an edition of 1920) preserved for generations on library shelves before it was carefully scanned by Google as part of a project of books digitalization. This book has survived long enough for the copyright to expire and the book to enter the public domain. A public domain book is one that was never subject to copyright or whose legal copyright term has expired. I believe this is an important starting point for those interested in learning about astrology.
The book “Aristarchos of Samos: the Copernicus of Antiquity” contains a translation of Aristarchos’s work “On the Sizes and Distances of the Sun and Moon” (Περὶ μεγεθῶν καὶ ἀποστημάτων [ἡλίου καὶ σελήνης) his only surviving work and in addition to that it also contains a very interesting review of the great Greek progress in astronomy from Tales to Aristarchos with a description of his pioneer “heliocentirsm” through the available sources. Certainly a "must read" for those interested in the history of Greek astronomy.