2. In the Closed Universe There Is a Stable and Eternal Immense Heat Ocean at a Temperature of about 3K
In 1965, Penzias and Wilson unexpectedly discovered the 3K microwave background radiation coming from remote space.(3) The background radiation shows three fundamental characteristics: (1) long term stability, (2) perfect isotropy, (3) its spectrum coincides with Planck’s formula for equilibrium thermal radiation at a temperature of 3K (i.e., black body radiation). They are exactly the same fundamental characteristics of the equilibrium radiation in a cavity within a solid at a constant temperature. Accordingly, what Penzias and Wilson discovered is an extremely immense and stable ocean of 3K equilibrium thermal radiation within the closed universe.
In any direction in the solid angle, all the observations inform us that the uniform and stable 3K background thermal radiation comes from extremely remote space.
People are curious, how deep is the heat ocean? How large is its volume?
The background radiation is an equilibrium thermal radiation. It is impossible to measure its depth directly by whatever an astronomic observation.
The heat ocean at the temperature of 3K is impossible to be infinitively large, its volume must be limited. Otherwise, according to the discussions by many scholars in the history since Newton, it would have been instable and collapse down.
The 3K heat ocean must be closed, that coincides with the close of the universe. Otherwise, the thermal radiation within the heat ocean would fly off and go far away, never return back. If so, the amount of the thermal radiation in the heat ocean would decrease ceaselessly, a stable heat ocean would be impossible to exit as we see it now. (2) (3) (4)
Many scholars regard that the 3K background radiation is the afterglow of the thermal radiation of the decoupled fire ball 380,000 years after the big bang when the temperature of the fire ball felt down to 3000K. The electrons and protons in the plasma in the fire ball combined to become hydrogen atoms. The fire ball decoupled. The particle matter in the fire ball become transparent, it no longer interact with the thermal radiation. They regarded further that the thermal radiation got free, flied out to the vast cosmic space and expanded adiabatically until it converted to a 3K thermal radiation, and its spectrum also changed to a Planck’s spectrum of the temperature of 3K.
What is the meaning by their “adiabatic expansion”? It is of course impossible to be a quasi static expansion occurred in a piston-cylinder like device. It should be a free ejection of radiation, similar to the free ejection of light and heat of the sun or any other star. The radiation of the light and other radiations of a star 10 million light years away from our earth are free ejection, when they reach our earth, the volume intensity of the radiation is already extremely weak, but its spectrum is still the same one as it just left from its mother star. The same thing happened to the decoupled thermal radiation. The decoupled 3000K radiation was then a free ejection, just like the light and other radiations of the sun or other stars. It would not convert to a 3K equilibrium radiation through an “adiabatic expansion”.
Let us go on.
The big bang and many of its follow up processes are all immense irreversible processes. All of these processes produce entropy, and according to the second law of thermodynamics, entropy can only be produced, never be reduced. Actually all these processes emit tremendous amount of light, heat and other radiations into the heat ocean.
First, the big band is a big explosion, and which, together with the following expansion of the primitive fire ball, are certainly huge irreversible processes. They scatter a great amount of light, heat and other radiations into the surrounding space, i.e., into the vast 3K heat ocean.
About 380 000 years after the big bang, the temperature of the expanding primitive fire ball dropped to about 3000K, the electrons and protons in the plasma in the fireball combined to become hydrogen atom. The matter in the fire ball became transparent. The thermal radiation and the matter in the fire ball no longer exchange heat each other, they decoupled. All the remnant thermal radiations in the fire ball got free, ejected out in all the directions, and entered the vast heat ocean (for more details, please read our new article in the appendix. (8) )
In the big expansion, numerous galaxies were formed, these processes were also irreversible. And, in all the galaxies, numerous nebulae developed into even more numerous stars, these processes were also irreversible. Then in a long period, there formed more than 2×1023 stars in the whole universe, like the sun, each star has a lifetime of about 1010 years, ejecting ceaselessly light and heat and so on due to the energy produced in their internal nuclear fusions. And so on.
All these irreversible processes in the various stages of the universe have a common point: they all finally release huge amount of energy in the forms of light, heat and other radiations, pouring into the 3K heat ocean. After entering the heat ocean, all these light, heat and other radiations, also shuttered around the central part of the universe ceaselessly in various directions, and gradually (with a very long relaxation time) mingled into the 3K thermal radiation of the heat ocean .
From another point of view, all the above processes are sending energy ceaselessly into the heat ocean. Although the 3 K heat ocean is very dilute, its volume and total mass are both extraordinary large. Hence, all the above mentioned large amount of input energy of light and heat, might only raise the temperature of the heat ocean very slightly. The temperature of the heat ocean is fundamentally stable.
Now, let us surmises briefly the structure of the 3K heat ocean itself.
First, let us calculate the mass density of the 3K heat ocean.
From the Stefan-Boltzmann’s law, the radiation intensity of the surface of a black body at
T = 2.73K is
As is well known, the relation between the radiation intensity of the surface of a black body
j and the energy density of the equilibrium thermal radiation in a solid cavity at the same temperature
u isdensity of the thermal radiation decreases to zero. Beyond
R2, is the infinitively vast empty space.
Hence, we have, at
T = 2.73K
Then, the mass density of the 2.73K thermal radiation in the heat ocean is,
Now, in our imagination, the central part of the heat ocean is the galaxy region, represented by a very small circle in
Figure 1. Next, containing the galaxy region and within the radius of
R1, is the
T = 2.73K region, as shown by the blue part in
Figure 1 and
Figure 2. Then, from
R1 to
R2 is the thermal radiation decaying region, as shown by the light blue part in
Figure 1 and
Figure 2, with the temperature falls down gradually from 2.73K to 0K, and with a mass decaying distribution function
as shown in
Figure 2. Finally, out of
R2, is the infinitively vast space, the cosmic vacuum.
In the 2.73K region, and, also in the thermal radiation decaying region, all the outward flying photons undergo red shift. Strictly to say, an outward flying photon is almost impossible (or very scarcely to be) precisely along the radius of the black hole. So, guided by their tangential kinetic energy, the photons will eventually turn back and fly towards the central part of the heat ocean, undergoing blue shift. All the photons in the heat ocean will keep shuttling ceaselessly in such a way, with the whole closed heat ocean keeps fundamentally stable and equilibrium.
As the heat ocean is extremely large, its total mass may also have some contribution to the gravitational close of the universe.
The authors allege, the tremendously vast 3K background radiation is a stable and eternal heat ocean. It exited before the Big Bang. It exits now. It will exist in the future. It is not the afterglow of the thermal radiation of the decoupled fire ball