What did Aristotle and his fellow Greeks discover?

Answer 1

Mostly every person interested in Science asks this question. Here is the list of greeks astronomers and their discoveries:

Pythagoras

Pythagoras (580?-? B.C.) was a philosopher and mathematician who is famous for formulating the Pythagorean Theorem, but the principles of the theorem were known earlier. Little is known about his early life but scholars suspect that he was born on the island of Samos. Around 529 B.C., he settled in Crotona, Italy. Pythagoras taught that numbers were the essence of all things and was responsible for starting the Pythagorean Brotherhood which was held in suspicion by the common people in that area. Most of the members of this brotherhood were killed in a political uprising. Pythagoras believed that the earth was spherical and that the planets have their own movements. His successors were responsible for developing the idea that the earth revolved around a central fire.

Plato

Plato (427?-347? B.C.) was born in Athens to a very distinguished family and became a philosopher and educator. Plato was really his nickname; his real name was Aristocles. He tried to enter politics twice, but was repelled by the politicians' disgusting practices, one of which was the condemning of his friend Socrates to death. In 387 B.C. he founded the Academy, which was a school of philosophy and science in Athens. One of his pupils at the Academy was Aristotle, who became famous as a philosopher. He created 36 literary works, 35 dialogues, and a group of letters. His works were mainly concerned with philosophy and ethics but he taught Aristotle at his Academy, who in turn contributed to astronomy and science.

Aristotle

Aristotle (384-322 B.C.) was probably the most learned philosopher in ancient Greece and was one of the most influential thinkers in Western culture. He and his teacher Plato are considered to be the most important Greek philosophers. Aristotle was born in a small town in the northern part of Greece named Stagira, but his parents died when he was young, so a guardian named Proxenus raised him. He entered Plato's school at age 18 and remained there for 20 years. After Plato died in 347 B.C., he left the school and married a woman named Pithias. Around 343 B.C., Aristotle became the personal educator of Alexander, the son of PhilipII, king of Macedonia. Alexander later became known Alexander the great when he conquered the Persian empire. Around 334 B.C., Aristotle returned to Athens and started a school called the Lyceum. Soon after Alexander died in 323 B.C., Aristotle was charged with impiety, which was lack of reverence for the gods. He fled to the city of Chalcis but died a year later.

Aristotle wrote on logic, philosophy, metaphysics, ethics, and politics. He wrote about the movement of heavenly bodies in his book On the Heavens and investigated the change that occurs when something seems to created or destroyed in On Coming-to-be and Passing-away. Aristotle was aware that the moon shines by reflecting light from the sun and was aware of the spherical shape of the earth because of the circular shadow it cast on the moon during an eclipse. Aristotle also expanded an idea introduced by Eudoxus (408-355 B.C.) who suggested many transparent shells rotating around the earth with the stars and planets on them. It did not explain the motions of the planets very well. Aristotle reasoned that the earth must be at the center of the universe because if it orbited anything else, it would leave its moon behind.

Euclid

Euclid (300? B.C.) is known as the father of geometry. His most famous work is a book, which was used as a textbook until about 1903, called Elements. In his book, he developed a system of geometry known as Euclidean geometry. Euclidean geometry can be divided into plane geometry and solid geometry. Plane geometry deals with shapes and concepts on a two dimensional plane, solid geometry deals with the study of three dimensional shapes such as cones and spheres. Plane geometry is still taught in all high school math books.

Archimedes

Archimedes (287?-212 B.C.) was a mathematician and inventor. He is called the father of experimental science by many historians because he tested his ideas with experiments. He discovered the laws of levers and pulleys and the basic laws of hydrostatics. He also found a more precise way of calculating the value of pi and invented a number system that was more workable than the Roman system. His inventions include the catapult and the Archimedian screw. He is most famous for finding a way of determining whether king Hiero's crown was solid gold. He first dipped a lump of solid gold, which was the same weight as the crown, in water and measured how much water overflowed the container. He then dipped the crown in the tub and measured the water that overflowed that time. If the amounts of water were equal, then the crown was solid gold. They weren't, and by this method, he discovered that the goldsmith who made the crown had cheated the king. Archimedes was killed when the Romans captured Syracuse, the town of his birth.

Eratosthenes

Eratosthenes (276?-194? B.C.) was a talented astronomer, poet, and historian who found a way to determine the size of the earth. He assumed that the earth was a sphere and that the sun was far enough away from the earth that the light rays coming to it would be almost parallel. Then he found that at the sun was directly overhead on the summer solstice at noon at a town called Syene because a pole cast no shadow. He also found that at noon of the same day at Alexandra, which was about 7 degrees or 4900 stadia (1 stadium equals about 0.16 km) to the north, a vertical pole casts no shadow. He then used Euclidean geometry to calculate the circumference of the earth at about 252,000 stadia (40,320 km) which was close to today's mean value of 40,030 km.

Aristarchus

Little is known about Aristarchus (200s B.C.) other than that he was a Greek astronomer who was the first to say that the earth revolves around the sun. His works were lost, but his ideas were quoted by the Greek mathematician Archimedes. In Aristarchus's surviving treatise On the Magnitudes and Distances of the Sun and Moon, he does not mention his theory on earth's orbit.

Hipparchus

Hipparchus (180?-125? B.C.) was an astronomer who was born in Nicaea and discovered the precession of the equinoxes. He found from records of earlier observations that the stars had shifted eastward. He explained that phenomenon by a slow westward motion of the equinoxes called the precession of the equinoxes. Hipparchus created the first star chart, which showed their brightness and position on a celestial sphere. He also distinguished between the different lengths of the solar and sidereal years. Based on his observations of the unequal length of the seasons, he drew up an improved description of the sun's movement. Of his writings, all were lost except for a commentary about an astronomical poem. Ptolemy absorbed everything of value from Hipparchus's treatises.