Ancient Greek Contributions..

Ancient Greek Contributions..Astronomy

By: Omar Al Harbi Abdullah Al Kanderi

• Astronomy is the science that has to do with the universe, much further than the earth’s surface. In other words, astronomy is the study of the stars, planets, etc.

What is Astronomy

Hipparchus• Hipparchus is one of the most influential astronomers of the old days and he named

850 stars!• He was born in Nicaea, Bithynia but lived in Rhode. • Some of his work that are now lost are like an astronomical calendar, books on optics

and math, geographical and astrological writing and a catalogue of his own work. • Ptolemy is considered the most important forerunner.• it is said that he may have invented the planispheric astrolabe .• Gerald Tomen credited Hipparchus with the founding of trigonometry• He is credited with the discovery of the precession of the equinoxes• He is interested in observing and recording the stars positions from years 147-127 BC

with a tool called dipotra.• He had theories like the theory of trepidation, sun and moon, and the length of the

year. • He made a catalogue of stars and estimated the distance from the sun and moon.• Ptolemy described Hipparchus as industrious and a great lover of truth.

Aristarchus• He was born about 310-230 B.C. on Samos Island (Aegean Sea)• He was a mathematician and Astronomer. • He figured out the length of the year.• Concluded that the earth was not the center of the earth. • The two things that he was best known for are:- The belief that earth revolves around the sun- Determined the sized and distance of the sun and moon.• He was a student of Starato of Lampasas in Alexandria.• He is the inventor of the Sundial its shaped like a Hemisphere bowl with

a pointer to cast shadows placed in the middle of a bowl.• He created the Theory of heliocentric system and that the planets move

around the Sun rather then Earth and the Greeks didn’t like that.

The World Without Astronomy

• Without Astronomy, We would not have the date and we would not know the length of the year because Astronomist were able to identify the exact length of the year. Therefore we wont be able to keep track of important dates and events.

• Also, without Astronomy, we wouldn’t have satellites to watch TV.