"Indeed there is a big gap, in terms of mass, between radiation and atoms to interpret gas winds as "radiation", even for a black hole. Probably, as the term suggests, it is something equivalent to solar wind."

Agreed, it is really a matter of how it is observed; I wouldn't put it outside the realm of possibility that some observed supermassive black holes have sufficient mass where their radiation is seen as atoms (at least in part). Certainly somewhere up in the scale, this is what occurs.

"for sure I suppose that even a galaxy will either move in a circular orbit around a bigger object or in a figure-8 orbit towards an even more massive object."

Exactly; perhaps there is a system our Milky Way galaxy orbits in a circular/elliptical orbit as part of a "galaxy of galaxies". The observation of peculiar motion towards the Great Attractor appears to suggest an electromagnetic field, but perhaps this is a gravitational redshift illusion and the Milky Way is just in a circular orbit. Which is the case would take some pretty meticulous research with these concepts in mind that I myself don't really even know where to begin.

Even if our galaxy is part of the electromagnetic field of the Great Attractor, the Great Attractor (and thus our galaxy) may be in a circular orbit about an even larger mass. Even if it is not, somewhere up in the structure of larger and larger systems there is one that is in a circular orbit.

Though everything appears to be separated by immense space, it also would be the case that somewhere up in the larger structures, there would also be a circumstance (an infinite number, in fact) where that system is tightly compacted with others of the same general mass into a single system (like Earth). Even though we may measure the distance of separation of each of these systems as extremely large, relative to their environment they would be so close that they would form a single system that observers composed of those structures would see these things as their planet and their atoms, completely oblivious of us experiencing reality many layers below them on what they may call a "photon".

"If I am not mistaken, neutrinos are heavier particles than photons. If this is true, then why neutrinos pass through the earth, but photons don't and most of them are actually reflected?"

Great question! And one that I don't have a complete answer for. I can say that atoms absorb light at specific wavelengths and everything else is not absorbed: absorption lines. Likely the answer to why neutrinos can pass through the Earth while photons cannot is linked to this. I have idly pondered on why this happens a lot, but haven't came up with anything I feel truly explains why this is happening. Perhaps I will spend some time to focus on it and look for more connections that may provide clues to help understand it, but for now all I can say about this is that absorption lines are within specific ranges, and so too is Earth's "absorption lines". Why that is the case, I haven't yet reasoned out :D

"For example, earth is a big dense area of atoms and we observe it as a single object relative to its "empty" surroundings. However, atoms, on a lower scale, are also tiny regular systems (like solar systems or galaxies). How could these small solar systems orbit inside and stay around the center of mass?"

I'm not quite sure I understand your question with regard to "orbit inside and stay around the center of mass"? Orbit inside of the Earth?

Like any system, atoms will pull surrounding matter through them and create a field that will prevent outside systems from combining with them. Gravity will compress these into larger systems and these fields keep them separate from one another (though with enough pressure they can be pressed together beyond the strength of their "force field" which will cause them to combine into larger systems). As the Earth's gravity is only so much, these particles are only able to be pressed together into the size of atoms, which is where they become stable for Earth. I know I'm not answering the question, but just some thoughts that come to mind. :)

"What could be the motion-forces-relations of these inner systems? (Note: mainstream physics says that atoms move randomly inside, however we do not see many random orbits/motion in bigger scale systems)"

I think I would need some direction on these questions to provide an answer that is actually directed at what you are asking; I'm not quite sure what you are referring to particularly in terms of individual atoms, atoms as part of the system of Earth, the forces within an atom, or what; I'd just be guessing and likely not giving an answer that is applicable to what you mean. If you could clarify, I will get back to you soon!

Thanks for the questions! I am glad to see that it generally makes sense to you; the amount of rejection and "crackpot" responses I get is immense. It is nice to see someone not think I am completely insane ;D. I definitely haven't figured it all out, every observation is like another puzzle that sometimes requires opening other doors of understanding before that "level" can be unlocked and the puzzle answer found. Absorption lines in general and neutrinos vs photon absorption of Earth are a great example of something I have been aware of but have "put on the back burner" as it seems some other links are missing before it can make more sense. To me, the simple model of infinity and gravity is only the gateway to understanding and all the complexity of everything being reasoned out from it is an endless task. The more uncovered though, the more certain it being truth rather than theory it all becomes.