We walk. Our pens fall down in the middle of class. Why does this happen? Well, we all know what newton thought when an apple fell near him. ‘Gravity’. It makes stuff stay on the ground. The absence of this in space makes us float around. But what is in fact, this force we call gravity?
We could, in simple words, define gravity as the force of attraction between any two bodies in the universe. This definition itself makes us realize how weak the force of gravity is. Confused? What do you do when the pen falls down in class? You pick it up. The earth, which is 5.9742 × 1024 kilograms, exerts a force called gravity, and you, much less than what we call tiny, when compared to the size of the earth, opposed the whole force of the earth, and picked up the pen. A better example would be, a tiny magnet picking up a paperclip.
Curvature of spacetime
So, why is gravity so weak? No one knows for sure. Of all the forces in nature, why did gravity become the weakest of them? Maybe gravity isn’t weak at all. It just appears to be weak as it has to travel through many dimensions. But what are those extra dimensions? No one knows that either. But actually, gravity is what was made by the curving of space-time by a massive object, like the sun.
