JP Michael wrote:
If earth's charge changes with seasonal direction changes in current, its relative mass and gravity should also change with season, albeit by amounts that do not overall peturb stable satellite orbits. These seasonal variations in mass and gravity might be measurable by recording miniscule changes in the orbital distance of the moon at apogee, perigee and semi-minor axes, relative to the earth charge season.
OK then, that's something measurable. If you exclude (in case of the Moon) tidal forces
, angular momentum exchange, perturbations from other planets, instrumental errors etc. and still see some oscillatory signal, then that might be what you're looking for. As I understand, the residuals
in current models of the lunar motion are of the order of 1 cm.
JP Michael wrote:
I did like your point, though:
paladin17 wrote:"Earth's surface has extra positive charge in northern winter, when it's closer to the Sun"
This made me think: I simply do not know anything about what effect gaining or losing positive charge has on overall charge, and thus mass and gravity. Perhaps the seasonal cycle of in-out doesn't actually change the overall earth charge, thus has no measurable effect on earth mass or gravity. I wonder if the same can be said of comets, since they experience radically changing environments of charge. That would be very difficult to research and observe, though.
I think the change in Earth's charge might be detected in situ
by observing the electric field in the atmosphere (or, alternatively, the ionospheric potential). Though it is actually dependent on space weather factors quite a lot (including even the time of day - see Fig. 1
). (A brilliant review
on that topic). Then there are longer time factors - e.g. the cosmic ray ionization of the troposphere is stronger during solar minimum (like right now). And cosmic rays also deliver a net positive charge, which should be dealt with somehow.
Overall, given the extremely complex multi-layered system (even the word "system" sounds too simple here) that is Earth I wouldn't expect naive electrostatic models to give any insights into the physics of our environment. All the observations indicate that the objects immersed in space plasmas act quite differently than a charged metallic ball in a vacuum would.