Classification | Cosmological medium | Conventional medium |
Basic unit | Virtual particle-antiparticle pair | Atom or molecular |
Investigation system | Large number virtual pairs | Large number molecules |
Leading interaction | Virtual Van der Waals force | Van der Waals force |
Inertia indexes | Vacuum mass density | Mass density |
Elasticity indexes | Vacuum elastic modulus | Elastic modulus |
Propagated waves | Cosmological acoustic wave | Conventional acoustic wave |