It is a knowledge that almost everything pushes others. To catch and to pull are not real acts. As a magnetic illusion. Magnetic illusion is the only exception. But it is still not a complete pulling, because a full merger does not occur.
When you kept a cup, actually you don't keep it, you are forcing to it to pull up. It is theorically like this, because no one of the particles never touches to the others.
This situation shows us almost everything on the nature pushes to the others.
This situation explains us two main events:
1- Difusion
2- Sky thrust (opposite theory of gravity)
1- difusion: All of objects pushes others so if one side is empty, almost all objects pushes the object which on the edge. This causes to object to move to the gap. Science calls it as diffusion".
2- Sky thrust : All of objects pushes the others.
So on the ground, Most of the objects are above on the chosen object on the ground. So the propulsion is the the greatest value. This makes the object as heavier. When the object go up, then some objects start to push it to up, though they were pushing down it Shortly before.
if an object passes the equilibrium position by going up continuously, The balance of power changes to outward then the object starts to fly with no way to return.