> If "touching" is taken to mean that two atoms reside in the exact same location, then two atoms never touch at room temperature because of the Pauli exclusion principle. The Pauli exclusion principle is what keeps all the atoms in our body from collapsing into one point. Interestingly, at very low temperatures, certain atoms can be coaxed into the exact same location. The result is known as a Bose-Einstein condensate.<p>This is a bit of a weird explanation, since the Fermionic matter (where the Pauli exclusion principle applies) and Bosonic matter (that can form Bose-Einstein condensates) are polar opposites.<p>Sure the Pauli exclusion principle is at least partially responsible for keeping electrons apart, but I'd be willing to wager that the electromagnetic force is the main thing keeping matter apart in normal situations. This <i>can</i> break down, for instance in neutron stars, but those situations are hardly normal.