A Mere history of Universe

Do you still remember arguing to your classmate that Earth is flat and not round? How about arguing to your sister that we came from a revolution of homonids and homos?

Well, I want to tell you, there were so many things that can be argued with.
In school we talked so may things about universe and heavenly bodies.
Many astronomers from the late centuries conducted their own discoveries and made a theory out of it.
Did you know that one of the biggest issues that astronomers fought with is how the universe looked like?

It known as the Geocentric Model Vs. Heliocentric Model.
They were many of them who created such models but the two are the overall classified ones.

Geo means Earth, this model shows that Earth is the center of the heavenly bodies (universe).
This is what Aristotle (one of the greatest astronomer, philosopher and scientist in the late era) written in his theory. He and other astronomers like Pythagoras and Eudoxus believed that Earth is at the center through observing how day goes by.
It is understandable because they lack materials in their time, and the so called "telescope" is not yet invented.

Helio means Sun, this model shows that Sun is the center of the universe. It is what Philolaus, Aristarchus and Copernicus (three out of many astronomers) believed. They made their own theory out of it. However, because of the lack of evidence their theories were not recognized. Until Hans Lippershey accidentally created a telescope! Whom Galileo used in his astronomical journey.

Until then more discoveries were conducted. And it was concluded that Sun is the center and not the Earth because of finding the "star parallax" which is very little to see. Stellar parallax is the apparent shift of position of any nearby star (or other object) against the background of distant objects.Once a star's parallax is known, its distance from Earth can be computed trigonometrically. (crdts: wikipedia)

Hey future astronomers! There are a lot more to see, this is a mere discussion on how our history quarrelled about this matter. Looking forward for your discoveries. ;)