Orbits

In his latest YouTube presentation, Wallace Thornhill puts into question gravity's role in planetary orbits. He suggests that gravity is a repelling force between stellar objects, implying that something different from gravity is keeping planets and moons in their orbits.

At first glance, this may seem like a refutation of the capacitor model of gravity in which I propose that gravity between large objects has a short range repelling factor, and a long range attracting factor. However, the difference between my position and that of Wallace Thornhill is in fact fairly small. We agree on the existence of a short range repelling force between large objects. We also agree on the existence of a longer range attracting force. It is only in the exact nature of these forces that our opinions differ.

In the capacitor model, the long range attracting force is the force we experience as gravity. In Wallace Thornhill's model, it is presumably a combination of the short and long range force that we experience as gravity on Earth. The long range attracting force is the one governing orbits in both cases.

The fact that there is a long range attracting force between large objects cannot be denied. Kepler pointed this out in the early 1600s, and Newton developed a highly successful theory based on Kepler's findings, combined with known attributes of our Moon's orbit around Earth.

From observations of our solar system, it is clear that the long range attracting force must be measured from the geometrical center of large objects, and its strength must taper off according to the inverse square law.

Coulomb's Law happens to fit the description of the long range force exactly, and this law is therefore featured prominently in alternative theories of gravity. It seems evident that there must be a close relationship between gravity and Coulomb's law.

From experiments with magnets, it is also clear that dipoles tend to follow the inverse cube law when interacting with each other. Opposing magnets mimic closely the short range repelling force presumed by both Thornhill and me to exist between large objects.

A repelling force obeying the inverse cube law would make it insignificant in almost all cases pertaining to planets and moons in our solar system. The long range attracting force is sufficient to explain all but a few minor oddities, the most prominent being that Mercury is not behaving quite as it should, and that our Moon is receding from us.

However, at the galactic scale, the inverse square law no longer holds. The rotation of galaxies are not even close to the speeds expected. This is due to the fact that galaxies rotate as large scale plasma objects in intergalactic electric fields. It is electricity that is the dominant force of the universe. Still, gravity may nevertheless have a role to play in explaining the observed rotational speed of galaxies.

In areas where large objects are relatively close together, the short range repelling force of gravity would come into effect. This repelling force, combined with the long range attracting force, would produce an overall effect where rotational speeds taper off more in accordance to the observed facts than is the case for a model where gravity has only a long range attracting element.

Specifically, we can predict that objects can move slower than expected. The closer objects are to each other, the slower they are allowed to move. Rotational speeds close to the center of a galaxy can be less than predicted based on the inverse square law alone. Only at a considerable distance from the center of galaxies will the changes in speeds be more in accordance to the inverse square law.

The overall effect of a short range repelling force in combination with a long range attracting force would be one in which speeds taper off less dramatically with distance from the center of galaxies. As the short range repelling factor tapers off, there will be a need for objects to speed up to compensate. This will partially cancel out the tapering of the long range attracting force that allows these same objects to slow down. The net effect would be a flatter, more linear, speed vs. distance curve than what the inverse square law predicts, which is exactly what we see.

Note: I've since come to realize that the repelling force is nothing more exotic than static electricity. All astronomic bodies have negatively charged surfaces. This counters the gravitational force that acts from the center of astronomic bodies. Hence, we get a stable arrangement for orbits.

Electric repulsion and gravitational attraction