They noticed comets, which they believed to be permanent bodies, revolving in orbits like those of the planets, only greater.

They ascribed eclipses of the sun to the interposition of the moon between the sun and the earth.

They had notions not far from the truth with respect to the relative distance from the earth of the sun, moon, and planets.

Adopting, as was natural, a geocentric system, they decided that the Moon occupied the position nearest to the earth; that beyond the Moon was Mercury, beyond Mercury Venus, beyond Venus Mars, beyond Mars Jupiter, and beyond Jupiter, in the remotest position of all, Saturn.

This arrangement was probably based upon a knowledge, more or less exact, of the periodic times which the several bodies occupy in their (real or apparent) revolutions.