Nicole Hayges Shyla Henry Period 4

1. Nicole Hayges Shyla Henry Period 4 The Greek Astronomers

2. Due to their contribution in mathematics and astronomy, Ancient Greek Astronomers are known world wide.

3. Aristarchus of Samos 310-230 B.C. Aristarchus is known for his suggestion of the sun being in the center of the universe instead of earth being the center of the universe. He also is known for his estimation of the distance from the sun to the earth by observing the angle between the moon when it is exactly half full.

4. Anaxagoras 500 B.C. • His most important idea was that people should not trust use their senses (seeing and hearing) or their common sense to tell them about the world, but they should always use logic and reason to figure out truth instead.

5. Thales Thales was the first Greek scientist that we know of who did not try to explain the weather and the stars and planets as things controlled by the gods. Thales was right that everything is made out of the same things, but those things are electrons and protons, not water. He understood that the earth was round, and that the moon was lit by light reflecting from the sun. Miletus, about 630 B.C.

6. Conon Conon was a Greek mathematician and astronomer. Headed the Alexandrian library after Euclid. Conon discovered a new stellar formation that he named Come (or Plocamos) Berenices, in honor of Berenice, queen of Ptolemaios III Evergetes. Samos, 283-222 B.C.

7. Eratosthenes of Cyrene 276-200 B.C. Greek astronomer and mathematician. Calculated the circumference of the Earth and finds a figure of 46,000 km which is close to the present measured value. Also lays down the first lines of longitude on a map of Earth. He also developed a method for calculating all prime numbers: the sieve of Eratosthenes.

8. Sosigenes He was a Greek astronomer and mathematician. His advice to Julius Caeser led to the adoption of the Julius calendar, which stayed in effect until 1578 when it was changed by Pope Gregory XIII. 1st Century B.C

9. Hipparchus of Nicea 190-120 B.C He was a Greek astronomer and mathematician. He’s Considered the greatest astronomer of ancient times. Developed a system of planetary motion with the Earth at the center. This system was later refined by Ptolemy. Used data from a total eclipse of the sun and parallax to determine correctly the distance and size of the moon. The same data gave values for the distance and size of the sun an order of magnitude smaller than there actual values. Compiled the first tables of cord length, forerunner of trigonometric tables.

10. Seleucus 190-? B.C. Last known astronomer to champion the heliocentric theory of the solar system until Copernicus.

11. Poseidonius 140-50 B.C He calculated the Earth’s circumference, which 1500 year later, led Columbus to believe that Asia was only about 3000 miles west of Europe.

12. Sosigenes 1st century b.c Greek astronomer and mathematician. His advice to Julius Caesar led to the adoption of the Julius calendar, which stayed in effect until 1578 when it was changed by Pope Gregory.

13. Ptolemy Claudius The last great Alexandrian astronomer. Refined the system of planetary motion developed by Hipparchus, which had Earth at the center of the universe, known as the “Ptolemaic System”. Best known for his Almagest

14. Hipatias The last ancient philosopher and astronomer. The only woman astronomer in ancient Greek history.

15. The End! http://www.greek-names.info/names-of-ancient-greek-astronomers/