Is gravity weak negative electric charge? [duplicate]

Question

This could be true since the both have infinite range and other common properties. They both have fields.

Answer 1

No. Take any 3 bodies, the sun, earth, and moon, for instance. Let's say that the sun is positive and the earth is negative. Then the sun and earth attract. But that means that, since the moon and earth also attract each other, the moon must be positive and be repelled by the sun. This does not happen - in fact, the gravitational attraction between the sun and moon is approximately twice that of the moon and earth. As a matter of fact, gravitational repulsion has (to my knowledge) never been observed, and this fairly conclusively establishes that gravity is not just a mistaken example of electrical force.

The Cavendish experiment was the first to experimentally determine the size of G, the gravitational constant, and measured the attraction of metal weights to each other. Due to the enormously larger value of even weak electrostatic interactions, part of the experimental protocol requires the establishment of electrical neutrality among all the weights.