It presented the sun as the centre of the system.

Around him the planets revolved in circular orbits, their order of position being Mercury, Venus, Earth, Mars, Jupiter, Saturn, each of them being supposed to rotate on its axis as it revolved round the sun.

According to Cicero, Nicetas suggested that, if it were admitted that the earth revolves on her axis, the difficulty presented by the inconceivable velocity of the heavens would be avoided.
There is reason to believe that the works of Aristarchus, in the Alexandrian Library, were burnt at the time of the fire of Caesar.

The only treatise of his that has come down to us is that above mentioned, on the size and distance of the sun and moon.
Aristarchus adopted the Pythagorean system as representing the actual facts.

This was the result of a recognition of the sun's amazing distance, and therefore of his enormous size.