Gravity is a weak force, but has only one sign of charge. Electromagnetism is much stronger, but comes in two opposing signs of charge. Electromagnetic waves are strongly interacting with normal matter, making them easy to detect; but they are readily absorbed or scattered by intervening matter. For two individual electrons, the electric force will be much more powerful at all points. For example, suppose they are 1 meter apart, find the gravitational force and the electric force on each electron, and then compare them.

Gravity is a weak force, but has only one sign of charge. Electromagnetism is much stronger, but comes in two opposing signs of charge. Electromagnetic waves are strongly interacting with normal matter, making them easy to detect; but they are readily absorbed or scattered by intervening matter. For two individual electrons, the electric force will be much more powerful at all points. For example, suppose they are 1 meter apart, find the gravitational force and the electric force on each electron, and then compare them.