Speed

Absolute zero gravity was a joke among scientists for decades. Could absolute gravitational force be a joke that has persisted for more than three hundred years? It is a very obvious thing that cloud is lighter than air, yet there is no way to prove cloud is lighter than air, since there is no way to weigh the air and obtain a weight value for unit measurement of air. Objects falling in the air are simply because the objects’ unit measurement weight is heavier than unit measurement weight of air. To gravitational force, only weight counts.