physci module 1

• They had a geocentric view of the earth

  early greeks
• They were not only great philosophers. They were great scientists and mathematicians as well.

  greeks
• It was in greece that the Golden Age of early astronomy was centered.
• The early Greeks had a geocentric view of the earth. For them, it was the center of the universe; hence, a motionless sphere. The sun, moon, Mercury, Venus, Mars, Jupiter, and Saturn orbited the Earth.
• Greeks called this sphere as the celestial sphere.
• its the shape of the Earth. It has bulging equator and squeezed poles.


  oblate spheroid
• either of the two times in the year, the summer solstice and the winter solstice, when the sun reaches its highest or lowest point in the sky at noon, marked by the longest and shortest days


  solstice
• an obscuring of the light from one celestial body by the passage of another between it and the observer or between it and its source of illumination.


  eclipse
• the astronomical model in which the Earth and planets revolve around the Sun


  heliocentrism
• any theory of the structure of the solar system (or the universe) in which Earth is assumed to be at the center of it all.


  geocentrism
• most Greeks believed that the Earth was round, not flat. It was Pythagoras and his pupils who were first to propose a spherical Earth.


  500 to 430 bc
• He observed that during a lunar eclipse, the Earth's shadow was reflected on the Moon's surface. The shadow reflected was circular.

  anaxagoras
• around 340 bc listed several arguments for a spherical Earth which included the positions of the North Star, the shape of the Moon and the Sun, and the disappearance of the ships when they sail over the horizon.


  aristotle
• was believed to be at a fixed position in the sky. However, when the Greeks traveled to places nearer the equator, like Egypt

  north star
• argued that if the Moon and the Sun were both spherical, then perhaps, the Earth was also spherical.

  aristotle
• argued that if the Moon and the Sun were both spherical, then perhaps, the Earth was also spherical.

  ancient scholars
• who gave the most accurate size during their time. While he was working at the Library of Alexandria in Northern Egypt, he received correspondence from Syene in Southern Egypt which stated that a vertical object did not cast any shadow at noontime during the summer solstice

  erastosthenes
• Sun makes an angle of 7.2° from the vertical while 0° in Syene.
• determined the angle the Sun made with the vertical direction by measuring the shadow that a vertical stick cast

  eratosthenes