Looking closely at the Rule of thirds

Rule of third is that an image should be imagined as divided into nine equal parts by two equally-spaced horizontal lines and two equally-spaced vertical lines, and that important compositional elements should be placed along these lines or their intersections.
BUT WHY?
why does they look good when placed at the thirds?
its because of THE GOLDEN RATIO ()

Beauty is in the eye of the beholder. 
IS it totally true? i believe that golden ratio has a lot to do with it. The definition of golden ratio can explain why things look good to eyes.

" if the ratio of the sum of the quantities to the larger quantity is equal to the ratio of the larger quantity to the smaller one" 

Beauty is not some  mathematical stuff .It can very well be defined theoretically 
Lets explain.
Look at that line again. If someone asks you to divide a line so that it will look beautiful . what will most of us do?  we will cut it in half i suppose. like when our mother used tell us to make our room tidy that what we used to do. keep things in the centre . Divide everything in half so that it looks good.

But Nature and also Artist( painters, sculptors, architects,cinematographers) doesnt follow that.
THIS IS WHAT THEY DO.

They would cut a line in such a way so that smaller part is related to bigger part in a same way the bigger part is in the relation with the whole.
And it lies a bit before or after the half.
That's why they created the rule of thirds as it lies closer to the golden ratio.

There a lot more to explain if we really want to understand golden ratio, as the whole nature is made out of it. 

some years back i was obsessed with this formulae . i have a lot to share. will do it some other time . i think this much information is enough to explain the RULE OF THIRDS.

if you have any questions, do ask.