were described mathematically by a set of perfect spheres.
Each planet circles in an epicycle.
Each epicycle circles in a deferent.
The center of all nested deferents
is a point halfway between the stationary earth
and the equant point.
Ptolemy claimed that his celestial spheres
were actually installed in the heavens—
concentric transparent crystalline spheres
spinning around above us.
Ptolemys
Ptolemy, Ptolemy, not those Ptolemys.
The other Ptolemys were pharaohs of Egypt
starting with a fellow from Alexander’s
army
who made himself pharaoh in 323 BCE.
Our Ptolemy died around AD 168
and was not a pharaoh.
Ours wrote a book on astronomy
and one on geography.
Wrote a book on astrology
to match the one on astronomy.
He wrote a book on harmonics
and another on optics.
All Ptolemys.
Disorder
It would be nice
if everything were
somehow in control;
however, total
control would tend to
stifle rock and roll.
Ptolemy, like Aristotle, deduced natural science from first
principles. All orbits were circular because the circle is the
most perfect geometric figure. Unlike Aristotle, Ptolemy tried to
adjust the model to fit the observations.
Ptolemy, like Aristotle, deduced natural science from first principles. All orbits were circular because the circle is the most perfect geometric figure. Unlike Aristotle, Ptolemy tried to adjust the model to fit the observations.
See also in The book of science:
Readings on wikipedia: