Static friction between elastic solids due to random asperities

Several workers have established that the Larkin domains for two three-dime nsional nonmetallic elastic solids in contact with each other at a disorder ed but atomically flat interface are enormously large, implying that there should be negligible static friction per unit area in the macroscopic solid limit. In contrast, the present Letter argues that when the Larkin domains are calculated for disorder on the multiasperity scale, they are much smal ler than the interface size. This can account for the virtual universal occ urrence of static friction.