Heliocentric vs Geocentric models of solar system

heliocentrism vs geocentrism gif

Credits: ibarabi

Observe the above video or GIF. Let’s take a look at what it is about.

The GIF is a highly simplified version of Heliocentrism. The planets do not revolve in perfect circles, but in ellipses as later found by Kepler.


Humans saw that the sun would rise in the east every day and then set in the west. So did all the stars and planets. Therefore they thought that the earth or the planet on which we are living on is at the centre of the universe and everything else in the sky revolves around it. This is called Geocentrism.

But this theory had problems which were slowly recognised by shrewd and observing humans. One of the problems was the retrograde motion of some of the planets in the sky. That is, some planets, during some weeks, appeared to move back in the sky as compared to their previous motion. You can see that as the sudden curls and twirls the planets go through in the above GIF.


Then came along Nicolaus Copernicus who proposed with a mathematical proof that the sun must be at the centre of the universe and not the earth and that we along with all other planets revolved around the sun. This led to some serious conflict with religious people. This model solved the problem of retrograde motion of planets and other problems as well. This model is Heliocentrism.

Think about this. If you had no idea about how planets behave, then our primitive human observations really do make us come to the conclusion that the Earth must be at the centre of everything. But when you start to go into detailed observations, that is when you come across some problems. And in science, you have to come up with a better theory than before to explain the new problems. That is how science works.

Stay curious.

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