**The Milesians**

The first recorded important contributions to
Greek science are from the city of Miletus, near the coast of what is
now Turkey, beginning with Thales in 585 B.C., followed by
Anaximander in 555 B.C., then Anaximenes in 535 B.C. Milesians were
the first to do science immediately recognizable as such to a
modern scientist.

Anaximander suggested that the earth was a cylinder, and the sun, moon and stars were located on concentric rotating cylinders. This is the first recorded attempt at a mechanical model of the universe. He postulated that the stars themselves were rings of fire. Again, this was a revolutionary suggestion, as all heavenly bodies had previously been regarded as living gods.

**Pythagoras**

Pythagoras was born 570 B.C. on the island
of Samos, near Miletus, and was a contemporary of Anaximenes.
Pythagoras is most famous for his theorem about right angled
triangles (the sum of the squares of the two sides is equal to
the square of the long side, called the hypotenuse). The theorem, now known as
Pythagoras's theorem, was known to the Babylonians 1000 years earlier
he may have been the first to prove it.

Pythagoras visited Thales in Miletus when he was between 18 and 20 years old. By this time Thales was an old man. He created a strong impression on Pythagoras, but probably did not teach him a great deal. He did contribute to Pythagoras's interest in mathematics and astronomy, and advised him to travel to Egypt to learn more of these subjects. Thales's pupil, Anaximander, lectured in Miletus and Pythagoras attended these lectures. Anaximander was interested in geometry and cosmology and many of his ideas would influence Pythagoras's own views. In astronomy Pythagoras taught that the Earth was a sphere at the center of the Universe. He also recognized that the orbit of the Moon was inclined to the equator of the Earth and he was one of the first to realize that Venus as an evening star was the same planet as Venus as a morning star.

**Aristotle**

In 367 BC Aristotle, at the age of seventeen,
became a student at Plato's Academy in Athens. Although in many areas
Aristotle advocated a modern scientific approach and he collected data
in a scientific way, this was unfortunately not the case in astronomy.
His astronomical views were biased towards absolute symmetry,
simplicity and perfection. Aristotle, proposed models where the stars,
Sun, Moon, and planets are attached to spherical transparent shells
undergoing uniform circular motion around the Earth. This is known as a
**Geocentric Universe**. He was correct however about the spherical
nature of the Moon, Sun and Earth.

Greek Science after Aristotle

Strato understood that falling bodies pick up speed (contrary to Aristotle's
assertions). Aristarchus gave a completely correct view of the solar system,
anticipating Copernicus by 2,000 years or so. Science flourished for centuries
in Alexandria, Egypt: Euclid
(and his book *Elements*), Apollonius, Hypatia (a woman!)
and others lived there, Archimedes studied there. Archimedes understood
leverage and buoyancy, developed military applications, approximated Pi
very closely, and almost invented calculus!