In the big rip scenario, dark energy will overpower all other forces and at some point space itself will expand so fast that the cosmic event horizon will be smaller than the smallest particle which means that nothing will be able to reach anything (even particles).
In the big crunch scenario expansion will stop at some point and it will reverse and in the end the whole universe will be concentrated in a point (just like before the big bang).
Equilibrium means that the expansion stops but does not reverse.
What do you mean by "surface tension"?
I was making an analogy to the behavior of fluids in our reality. Really though, what I was getting at is, do we, or can we, really know the nature of the universe to such a degree that we can rule out behaviors which may change as the universe progresses through whatever sequence of events through which it is progressing? I think you answered my question, such as it was.
Ok but, armchair amateur here, the scale of space is not known to humans, right? We cannot comprehend the actual limit of the universe, can we? How can we know that the universe entering a dark age is not a local effect in our known universe, and that other, incomprehensibly distant parts of the universe will keep doing just fine?
For that matter, if the universe enters a dark age, what is it that caused the universe to be in a "light age" in the first place? There has be a force that causes the universe to exit a "dark age" otherwise it would always have been dark.
These kinds of things perplex me.
It is fine to attempt to apply our rubrics, but I am not sure how to quantify the limits of our perception. Perhaps Occam's Razor and current simpler theories give a useful working tool for us to reason within our local known (or perceived/comprehended) universe.
The best way I can think of to ask this is, how do we factor in the "unknown unknown"? It is maddening not to be able to.
If you have other reasons to believe a more complex hypothesis may be likely those should generally override Occam's Razor.
https://en.wikipedia.org/wiki/Occam%27s_razor#Justifications
> "[1:2] And the earth was without form, and void; and darkness was upon the face of the deep. And the Spirit of God moved upon the face of the waters. [1:3] And God said, Let there be light: and there was light.
If you'd like to read more, here you go: https://www.blueletterbible.org/kjv/gen/1/1/s_1001
I will note that in the above it says "morning" and "evening". In some sense, the writing is old enough that we assume that is what the original hebrew meant, but we don't actually have context to say. I've heard that the word for "morning" (erev) could have meant "order", and "evening" (boker) could have meant "disorder".
So what you get is 7 days (depending on who you ask) where the second law of thermodynamics is "wound up", if you will, which resulted in an ordered universe that isn't just a homogeneous soup.
I encourage you to take some time and study the Christian church during the Middle Ages. Much of what we consider 'modern' learning, teaching, and method came about because there were monks an nuns who were very serious about their work.
Likewise, I encourage you to study Islam since its inception; there also clerics (I don't know the proper terms) sought to increase understanding in literature an science some 500 years before the church in Europe.
Also take some time to look into various religious orders (Hindu, Buddhism, and others) throughout Asia that, in very similar fashion, worked to preserve and expand knowledge within their orders and in their surrounding communities.
If anything, religion has been a driving force towards foundational methods of understanding, knowledge acquisition, and preservation.
Please... please don't imply that the book of Genesis, or any similar religious work, holds some hidden insight into modern science. The authors of Genesis, whoever they were, did not know what thermodynamics was, and were not writing about it when they came up with the Genesis account.
I didn't. Nor was that my intent. I only wanted to point out that there was something interesting and relevant to the above post.
My intent was to add an extra dimension to the conversation.
We don't know the scale, that's why we usually say "observable universe", but we do know the rules which apply everywhere.
"light age" or whatever you call it in this context means that there are still stars left which emit light.
After the "dark age" there will be the heat death of the universe.
The cosmological event horizon is caused by the accelerating expansion of the universe. Space is expanding uniformly, so the more space there is between us and some object, the faster it is moving away from us. Objects that are farther than the Hubble Distance from us are receding faster than the speed of light, and so their light will never reach us. Over time, everything that isn't gravitationally bound to us will recede into the distance, redshift and disappear, leaving only our galaxy within the observable universe.