Vergelijking tussen elektrische en zwaartekracht

The Coulomb and the gravitational interactions both depend inversely on the square of the distance between the point objects. Whereas gravitational interaction is always attractive, Coulomb interaction may be attractive or repulsive depending on the signs of the electric charges.

Gravitational interaction depends on the product of the point masses, whereas Coulomb interaction depends on the product of the point charges.

Take two electrons and consider the gravitational and electrostatic forces they exert on each other. When the magnitudes are compared, the distance dependence cancels.

The ratio depends on universal constants and the electron's mass and charge. On substitution of their numerical values in SI units, it turns out to be of the order of 10⁴².

This enormous number implies that electrical forces are significantly stronger than gravitational forces. For example, a rocket is propelled by electrical forces against the pull of gravity.

If there is an electrical force, charged particles move and neutralize it, making objects around us electrically neutral.

Although the gravitational force is weak, it cannot be neutralized. So, it extends over astronomical distances.