Originally Posted by bweezie
So, this isn't really a question. Just some thoughts I have had. Disclaimer, I am a layman never formally study physics, but it is something I have always been interested. Please forgive me and correct me where ever I am wrong.
I have been watching a couple different documentaries and read a couple different books. They have ranged in topics, but specifically I have been curious about two things in particular. Absolute 0 and the end of the universe. For instance, one documentary was talking about the cooling of liquid helium to just a nano kelvin above absolute zero. How the helium then behaves quantum mechanically and all of the helium behaves as one entity. Really interesting stuff in its own right. Here is a link for a clip of the documentary. Ben Miller experiments with superfluid helium - Horizon: What is One Degree? - BBC Two - YouTube
The second part of my thoughts were concerning the expansion of the universe and eventual end. How all galaxies are moving away from all other galaxies. Eventually even stars within a galaxy will start to move apart and then planets etc all the way down atoms themselves moving away. Essentially, how I am interrupting this is that the universe is approaching absolute zero. The energy density of the entire universe will gradually get closer and closer to 0. Am I wrong here, because what this tells me is that if we combine these two ideas of a substance close to absolute 0 behaves quantum mechanically, as "one" and the universe expands to the point where it is uniformally nearly absolute zero. I suppose this is where my question is. What does this actually mean? I see it as kind of a default reset that the universe is operating as the singularity it was in the beginning and everything would start over. These are kind of lofty ideas, but I am curious to see what an actual physicist would say.
I'm not a physicist, but I do have it somewhere in the back of my mind there is a theory that the heat death of the universe will resemble the beginning of the universe.
Unfortunately I can't remember who came up with this theory, but I am sure it is taken seriously in cosmology.