Astronomy was a subject of Mathematics in Greece. Ancient Greek people made models to represent celestial objects such as the sun, moon, and planets. This began when Pythagoreans started to relate astronomy with four mathematical art forms along with music and geometry. The geoconcentric model is the most famous and old concept about dividing the cosmos into two parts. This concept is also called as Helioscopic model of the universe.

Plato, one of the ancient philosophers writes in his two books 'Republic' and 'Timaeus' about cosmology. The books say that eight spheres carry the seven planets and the fixed stars in space.

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"The stars in the heaven sing a music only if we had ears to hear"
-Plato
```

Eudoxus gave each planet a concentric circle and also tilted the planets and assigned them different times of revolution, making Eudoxus the first person to give a mathematical model. The scales and numerics given by Eudoxus were called the Eudoxian system. Greece had the most ancient and accurate astronomers such as Aristotle and Callipus.

**Let's get into some facts about Greek mythology:**

**1.Earth orbits the sun- **

They called the sun the 'Central fire'. Aristarchus of Samos was the one to say that sun is at the center and he placed all the planets in the correct order of distance from the sun. He also knew that the sun was much bigger than the moon. This was during 310 BC and the evidence of his work was lost in history. Later, in the 16th century, Copernicus rediscovered this concept.

**2.The first astronomical calculator-**

Greeks were the first to design a working astronomical calculator and it is one of the oldest surviving mechanical calculator. It was built during a shipwreck on the island of Antikythera in 1900 but the maker of this fascinating device is unknown. Some people believe this could have been the work of Archimedes. The calculator consists of gears and when rotated with a hand the distance between planets, timings of lunar eclipses, and phases of the moon can be found out. Such a gearing technology was not found until thousands of years.

__Photo credit-____www.ancient-origins.net__

**3.Circumference of the Earth and size of the Moon-**

Eratosthenes was one of the librarians who was fond of experiments. He was the oldest one to tell the numeric value of the circumference of Earth. Eratosthenes simply used two poles poking them in the ground. He measured the shadow cast on the ground on a midday during summer solstice. The estimated circumference of Earch found by him was around 40,000 kilometers.

One of the books by Aristarchus survived which was about the moon and the sun. He knew that the Earth, sun, and the moon formed a triangle when the moon was in the first/third quarter. Aristarchus estimated that the size of the moon was around one-third that of the Earth based on the timings of the lunar eclipses.

Ancient humans were much more aware of the universe than us without modern technology only based on their mathematical knowledge and experiences.

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