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As far as I know things like rocks, walls, rubber balls, polished tables etc. exert a short range repulsive force on other everyday objects that is responsible for hardness, softness, collisions, friction etc.

Take a pair of electrically neutral solid materials. I am not interested in pairs of magnetic materials or astral bodies. Related to this I have a question:

Are there any such pairs with significantly longer range repulsions? So significant, in fact, that we can observe them repelling each other at large macroscopic scales. Could such materials have applications like anti-gravity?

orange_soda
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  • The repulsive force is referred to as Pauli repulsion or Pauli exclusion and it's due to electron overlap. It can be calculated using regular QM to calculate the electron overlap, though the calculations may take lots of computer time. Search this site for many questions on Pauli repulsion. I don't know of any long range force of the type you describe. See http://physics.stackexchange.com/questions/71846/is-the-electromagnetic-force-responsible-for-contact-forces and the links therein for more. – John Rennie Nov 06 '13 at 07:09
  • look at Van der Waals forces (spill over :dipole, and higher moments from the nucleus-electron complex ) – anna v Nov 06 '13 at 07:17
  • @dj_mummy: I'd be surprised if there were any shortcut to the calculation, though my guess is that the hard shell repulsion in a solid is basically the same as between individual atoms. So just take the pairwise atomic potential and add it up for all the interacting atoms. – John Rennie Nov 06 '13 at 10:39

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