Statistically, the Universe is in a state of thermodynamic equilibrium due to the existence of two thermal subsystems: an outer subsystem and an inner subsystem. These are separated by a one-way adiabatic barrier (a vacuum-gravitational barrier, i.e. the space between the matter of black holes and their event horizons). The inner subsystem consists of parts distributed uniformly (on a large scale) within the outer subsystem. These parts are black holes. The outer subsystem comprises the remainder of the Universe, i.e. the visible part. The ‘role of the coexistence’ of both subsystems consists in maintaining thermal energy at a constant level relative to other forms of energy. This is possible thanks to the continual collapse of fragments of the outer subsystem into parts of the inner subsystem, one-way adiabatic isolation between the subsystems, and the continual return of parts of the inner subsystem to the outer subsystem.
Indeed, the black-hole matter absorbs all forms of energy from its surroundings. This is made possible by gravity and a one-way adiabatic isolation. It enables the flow of thermal energy from a subsystem of lower temperature to black-hole matter of higher temperature, but not in the opposite direction. Energy (here: heat) increases faster than mass; that is, the ratio of thermal energy to mass continuously grows. Once a sufficiently high energy-to-mass ratio is reached, the matter attains a volume large enough for part of it, in the form of elementary particles (Ambartsumian’s pre-stellar matter), to cross the event horizon. Through gravity, hydrogen is synthesized from these elementary forms of matter (Ambartsumian’s pre-stellar matter). The reconstructed forms of energy are then dissipated again into the outer subsystem.
Thanks to gravity, energy and mass continuously circulate between the subsystems, and the relative and absolute quantities of their respective forms in both subsystems remain constant. Due to this “interaction,” both the outer and inner subsystems are statistically in a state of thermodynamic equilibrium. This is further supported by the fact that they exist for infinitely long periods, do not statistically interact with their surroundings, and occupy a statistically fixed domain. The outer subsystem — of which we are a part — is therefore in a state of thermodynamic equilibrium and has a temperature of 2.736 K. This is observed as the microwave background radiation (in the Big Bang Theory, the “relic radiation”). The hypothesis is also supported by Arthur Eddington’s 1926 determination of the temperature of interstellar space as 3.2 K, obtained by summing starlight and transposing it into thermodynamic equilibrium conditions [19]. Further confirmation is provided by the fact that the microwave background radiation is identical in all directions [15, 20]. Minor deviations in the spectrum from the ideal Planck distribution for a perfect blackbody at 2.736 K result from the cycle of energy (and mass) circulation between the subsystems.
In summary, the Universe is a perpetual motion machine of the first kind, but it does not violate the first law of thermodynamics because:
- the Universe contains two thermal subsystems;
- each subsystem is in a state of thermodynamic equilibrium;
- the subsystems are statistically isolated by a continuous, one-way adiabatic barrier allowing heat flow from the outer subsystem (lower temperature) to the inner subsystem (higher temperature);
- individual parts of the inner subsystem may increase in temperature while the subsystem as a whole remains in statistical thermodynamic equilibrium, since those parts that “explode” reduce it;
- parts of one subsystem transition into the other subsystem and vice versa;
- ordered energy is reconstructed from thermal energy;
- heat extracted from the outer subsystem is converted into work by the inner subsystem (black holes as a whole — functioning as a perpetual motion system of the second kind — do not violate the second law of thermodynamics because their entropy does not change statistically).