It was Johannes
Kepler (1571-1630) who made the revolutionary decision that
heavenly bodies might move in some other shape than a circle.
This decision did not occur until after he had the Danish astronomer,
Tycho Brahe's (1546-1601) accurate observational data available.
When he wrote his first book, the Mysterium Cosmographicum,
he was a dedicated Copernican but had not yet arrived as his elliptical
Prodromus dissertationvm cosmographicarvm, continens Mysterivm
cosmographicvm, de admirabili proportione orbivm coelestivm,
de qve cavsis coelorum numeri, magnitudinis, motuumque periodicorum
genuinis & proprijs, demonstsratvm, per qvinqve regularia
Tvbingae, excudebat Georgium Gruppenbachius, anno MDXCVI.
In many ways
Johannes Kepler, known to us for his three laws of planetary
motion, was a mystic. Thinking about how God would have made the
universe, Kepler devised a scheme whereby he deduced the structure
of the universe without the inconvenience of observation. As he
pondered the arrangement of the planets, he decided that God determined
their spacing around the sun using the five regular geometric
solids. Kepler, a convinced Copernican, knew that there must be
a correlation between the six planets known to Copernicus and
the five regular solids. In his first book, the Mysterium cosmographicum,
published long before he postulated that the planets moved in
ellipses, he was convinced that he had discovered God's mathematical
plans for the construction of the universe.