This is a static view of two series atoms or dipoles.


This is how they might rotate in-phase.


Note the pulses below when they align in-series. They also may align by Brownian motion without the rotation.

When they align momentarily, there is a pulse of series force.The pink series force is stronger than the green series force. The pink force lasts longer and the charges are closer together. It is this very short electrical pulse which produces gravity and inertia. The extreme shortness of the pulses explains the weakness of gravity comparedto the continuous force between charges.

The dipoles are rotating at 6E15 hertz. This is 6 petahertz. We should be able to make machines to operate at this frequency in 10-15 years according to Moore's law to verify this hypothesis.

The attracting electrons and protons are moving in opposite directions. They pass each other at 6E15 hertz squared. If we say the dipoles align for 1/20 of a degree or 1/7200 of a revolution, then we have,
1/(7200)2 * 1/(6.576E15)2 = 1/(2.242E39),
This is the ratio of gravitational to electrostatic Coulomb forces. Gravity is so much weaker than electrostatic force because of the short duration of the in-line interaction of the pulses of force between the in-phase series dipoles.