If electron has mass and gravity says mass attract each other ,than why are there negative repulsion?

Question

Does relativity theory explain this in terms of space time repulsion of electrons with each other?

Answer 1

Gravity is one of the four (maybe five) basic forces known in the universe. Electromagnetism is another. Gravity is comparatively weak, electromagnetism is comparatively strong, so the force of repulsion overcomes gravitational attraction. The other two known forces (the weak and the strong) exist inside the nuclei of atoms.

Answer 2

Let's quantify the relative strength of the electromagnetic force vs. gravity. We'll use simple approximations.

Gravitational force at 1 meter for two electrons:
F= GmM/r^2 = (6.7 x 10^-11) (9.1 x 10^-37)^2 = 5.5 x 10^-83 N

Electrostatic force at 1 meter for two electrons:
F= kqQ/r^2 = (9.0 x 10^9) (1.6 x 10^-19)^2 = 2.3 x 10^-28 N

Gravity is a weak force to begin with, but the tiny mass for the electron makes its influence infinitesimal. It is ignored entirely in nuclear and particle physics, except in extreme cases (neutron stars and the like), and in understanding cosmology.

Answer 3

It is because the electrical repulsion
between two electrons, for example, is some 10^40 times stronger.

Answer 4

Gravity says mass attract each other.
Electriciy says same charges repel each other.

Since force of attraction due to graviy is less than the force of repulsion due to like negative charges; repulsion prevails.