The decoherence time over superposition displacement R is proportional to R -2 , ensuring that decoherence becomes faster for more extensive separations. Extensivity. The gravitational self-energy increases with the system's size, yielding extremely tiny collapse times if all atoms are displaced in the coherent state, as we can see in the examples of Figure . However, in realistic situations, the quantum superposition may be restricted to small subregions of the system, with most of the molecular environment undisturbed. In such cases, the collapse time would be long, even for macroscopic objects. We saw such an example when we discussed the superposition of vacancies in iron crystals, where the effective size factor in (9) was harshly reduced to NSM 2 (NS << Nat).