Geoheliocentric

Precursors to geoheliocentrism

Tycho was not the first to propose a geoheliocentric system. It used to be thought that Heraclides in the 4th century BC had suggested that Mercury and Venus revolve around the Sun, which in turn (along with the other planets) revolves around the Earth. Macrobius Ambrosius Theodosius (395–423 AD) later described this as the "Egyptian System", stating that "it did not escape the skill of the Egyptians", though there is no other evidence it was known in ancient Egypt. The difference was that Tycho's system had all the planets (with the exception of Earth) revolving around the Sun, instead of just the interior planets of Mercury and Venus. In this regard, he was anticipated in the 15th century by the Kerala school astronomer Nilakantha Somayaji, whose geoheliocentric system also had all the planets revolving around the Sun. The difference to both these systems was that Tycho's model of the Earth does not rotate daily, as Heraclides and Nilakantha claimed, but is static. He was also anticipated by the cosmology depicted in the Leiden Aratea, a Carolingian manuscript created in the early 9th Century for the Carolingian court.