In dealing with electricity, we usually refer to Earth as the electrical neutral or ground. Is there any evidence that other planets' ground is at the same electrical potential level as the Earth's?

If somehow, there was a lossless conductive connection between two planets, would current flow accros It? Would this be theoretically a source of energy?

  • $\begingroup$ If you connect electrically neutral and electrically neutral, then you get... $\endgroup$ Feb 7, 2020 at 7:24
  • 1
    $\begingroup$ Different but related: What are the experimental limits to the residual charge of the Sun? This is an interesting question; the net charge on a planet is not necessarily zero; since the mobility of electrons and ions is so different, there are magnetic fields involved and a constant supply of ionized particles from the Sun. You might consider asking specifically about the Earth's net charge as a separate question in Earth Science SE. $\endgroup$
    – uhoh
    Feb 7, 2020 at 10:15
  • $\begingroup$ I have also found a somewhat related question here: physics.stackexchange.com/questions/253475/…. $\endgroup$
    – Kavka
    Feb 7, 2020 at 15:36
  • $\begingroup$ Kavka, don't overlook the option of posting your own answer to this question if you find the links in the other comments lead you towards a solution. Self-answering is actually encouraged at Stack Exchange - in fact there's a specific badge you can earn! :-) $\endgroup$ Feb 11, 2020 at 0:18

1 Answer 1


I dunno how or why a planet would have a significant net charge, but supposing it did, here's some initial calculations.

If the planets have a different net charge, you can treat them as capacitor plates.
Capacitance in its simplest form is

$C = \frac{\epsilon *A}{d}$
The permittivity $\epsilon$ of vacuum space is 8.85 x 10-12 farad per meter . Let's choose a nearby (nonexistent) planet at 5 LY = 5 * 9.461e+15 m .

Looks like the capacitance is pretty close to zero. So the energy available,

$E = \frac{CV^2}{2}$ is going to be nonexistent unless there's a seriously large voltage.


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