There is a sphere, of similar radius to Earth, but the mass of this sphere is such that it's gravity is negligible, and if gravity was the only force on this sphere, any gas or liquid that was put on the surface of this sphere would quickly float off into space. Although gravity is negligible on this sphere, this sphere has about the same amount of electric charge as Earth has mass.

Could this sphere maintain an electrically charged atmosphere, and electrically charged oceans for billions of years?

  • 4
    $\begingroup$ Charge and mass use different units that are only tangentially related, and using different unit systems will result in different values. It makes about as much sense to say "as much electric charge as the earth has mass" as it does 'A light as bright as this car is fast." $\endgroup$
    – notovny
    Jul 9, 2020 at 16:03
  • $\begingroup$ The nature of charge is that it's a surface effect, electrons (- charge) repel each-other so they distribute themselves as far away as possible (around the outside of an object), the same goes for holes (+ charges) see: static electricity - energies involved. Are you looking for local variations that last over time (discharge/insulation issue), or a whole planet with a particular charge? $\endgroup$ Jul 9, 2020 at 16:20
  • $\begingroup$ @notovny When I say that it has about as much electric charge as Earth has mass, what I mean is that anything with the same electric charge to mass ratio as the sphere, at the same distance from the center of the sphere as the radius of Earth, when thrown not on the surface of the sphere, will accelerate towards or away from the sphere at about the same rate as an object in free fall would accelerate towards the Earth. Comparing Electric Charge to Mass is more like comparing distances in space to distances in time. $\endgroup$ Jul 9, 2020 at 16:50
  • $\begingroup$ "Anything with the same electric charge to mass ratio as the sphere": doesn't the question say that the mass of the sphere is negligible? If by "oceans" you mean actual oceans of actual water, their mass is most definitely not negligible. To have the same ratio of charge to mass the oceans would have to have a very very large charge, dwarfing the charge of the sphere. $\endgroup$
    – AlexP
    Jul 9, 2020 at 18:26

1 Answer 1


No. The only way to keep opposite macroscopic charges separate is to have a dielectric in between. Without the dielectric the two charges would recombine, giving the nice zapp you get when you get an electrostatic discharge.

Moreover, an atmosphere of only charged constituents would disperse even faster than what a neutral gas would do in the same condition, due to the coulumbian repulsion.

  • $\begingroup$ What if only a small fraction of the molecules in the atmosphere were electrically charged, and the sphere had a layer of a substance that was an insulator between the electrically charged surface and electrically charged interior? $\endgroup$ Jul 9, 2020 at 23:47

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .