Geocentric VS Heliocentric in history

Around 350 BC, Aristotle was a Greek astronomer who convinced all people that the Earth is round. He said that if the Earth is flat, then we cannot see the Earth's shadow as round in the Moon (during an eclipse), rather then it will appear as a straight line.

Even Aristarchus, Another Greek Astronomer, suggested that Earth is orbiting centered Sun. But Aristotle and many Greek scholars rejected the idea of the Sun at the heart of our solar system. The highlighted argument they give was that if it is true, then we can also see the phases of Venus, like the moon, does. (It was not possible at that time to see a large distant Venus's phases with naked eyes).

venus phases

At that, it was believed that the Sun is the planet with the Moon, Mercury, Venus, Jupiter, Saturn, and Uranus. And they all orbit the Earth. Greeks thinkers had no telescope that they can observe it directly, so what they can notice is a sky - filled with stars and planets. We all know that the moon and planets also glow in the night sky. So, this was a common observation for the Sun as same as another planet.

When Aristarchus presented the Idea of sun-centered, there was a lot of question about it, which was unanswered, this forced Greeks to stand with their Idea of the earth-centered solar system.

The idea of earth-centered solar system gets a boost from mathematician Ptolemy who made the planet's position predictable at their desired time and date. In the geocentric model, Ptolemy assumed that the planets also orbit a small circular path in their orbit around the earth. He thought so because of his mathematical calculation to relate the naked eye observation of planets in the sky. You can see this in 2 fig in this post.

It is impressive that with false information, he did it, and that's why he is one of the greatest mathematicians in history. Then the idea of the geocentric model had not disturbed for around 2000 years in the western world. 

An Indian astronomer Aryabatta in 5 century had written in his work about the heliocentric model in which he shows that planets are spinning on its axis while orbiting the sun. He also presented the elliptical orbit of planets. With these things, he was able to calculate the accurate time of the solar and lunar eclipse. His work 'Arayabhatiya' was translated in Arabic in the 8th century and then in Latin in the 13th century.

Geocentric solar system

And after a century, Nicolaus Copernicus had presented the heliocentric model of the solar system in the western world. In his model, he showed that the sun is at the center of our solar system, and planets - Mercury, Mars, Earth, Venus, Jupiter, Saturn, and Uranus orbits the sun. 

In the next century, when Kepler published his 3 of 2 of his planetary laws in 1609 and in the same year, Galileo had invented a telescope (not the first telescope) and see the phases of Venus. Now it was proved that the sun is the center of our solar system.

Note: In geocentric model Ptolemy assumed that the planets are also orbit an circlar path in the earth orbit for his mathmatical calculation to relate the practical naked eye observation from earth.
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