Dismiss Notice
Join Physics Forums Today!

Does the vacuum of space have finite electrical resistance?

  1. Oct 13, 2013 #1
    Air typically has a very high but non zero resistance. Given that air is just a medium, and that space is also just a medium, does the vacuum of space have a fundamental constant of electrical resistance, or is the electrical resistance of space truly infinite? How is this proven one way or the other, or can it even be proved at all realistically? Given that space has charged particles popping in and out of existence, my hypothesis is that space does have a finite value of electrical resistance, although it is extremely high. A high enough voltage could polarize charged particles in space and possibly cause a current to flow.

    Assuming you had limitless voltage, could you make any current flow across two points in vacuum space?
  2. jcsd
  3. Oct 13, 2013 #2


    User Avatar

    Staff: Mentor

    Google for "vacuum tube".
  4. Oct 13, 2013 #3
    1. With a high enough charge density, virtual electrons can be popped out of the vacuum. The experiment was two nuclei colliding, which popped out electrons.
    2. High intensity microwaves will cause arcing in the vacuum; although, the usual photos are in air, which arcs more easily (the electrons are readily available).
  5. Oct 14, 2013 #4


    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

    If space had infinite electrical resistance, it would be impossible for radio communication to exist between earth and spacecraft. Radio telescopes would be giant hoaxes.
  6. Oct 14, 2013 #5
    the thing is maybe with a few hundred volts space really is a perfect insulator but once the voltage goes high enough , or as in your hypothetical example is limitless or infinite a current path can indeed form in a vacuum carried out by electrons as they can form a current also through vacuum , hence why Nugatory suggested for googling vacuum tube.
    remember that not the actual electrons are the first one to make the connection but the field , in this case the electric field which can go through space and indeed does so and attracts oppositely charged particles.
  7. Oct 14, 2013 #6
    A true vacuum would have infinite electrical resistance because there is nothing to carry the current. Even interstellar space is far from a true vacuum though.
  8. Oct 14, 2013 #7
    You must be thinking of electrical permittivity, radio communications don't rely on any type of conduction in the medium.
  9. Oct 14, 2013 #8
    Even a true vacuum would eventually break due to virtual particles being pulled from the vacuum and becoming real electrons and positrons (where the energy for the pair production would come from the static electric field energy density). A dimensional analysis shows that the electric field needed for that to happen would be of the order of [itex]E \sim \frac{m_e^2 c^3}{e \hbar} \sim 10^{18} V/m[/itex]
    That's clearly an absurdly large electric field.

Similar Discussions: Does the vacuum of space have finite electrical resistance?