Metastable Objects in the Universe and Their Possible Relation to “the Arrow of Time”

A relation of the presence of metastable objects with various “lifetimes” in the Universe to both an increase in the entropy and “the arrow of time” is discussed. A finite lifetime of metastable objects makes it possible to assign many of them with their own “local clocks.” The decay of any metastable system in the Universe results in the appearance of more stable objects with the emission of photons and other particles. These photons and particles interact with particles of more stable subsystems in the Universe, leading to their ergodicity. The emission of photons from decaying metastable states in the expanding Universe makes these processes irreversible and specifies the arrow of time although the equations describing these physical processes are reversible.