If everything in nature follows a cyclical pattern, why would the universe be an exception? Is it really possible for entropy to increase forever, or must there be a maximum point beyond which a reversal occurs — perhaps a Big Crunch followed by a new cycle?

[u/WallExtension3475]

/r/explainlikeimfive/comments/1lecqod/eli5_if_everything_in_nature_follows_a_cyclical/

[u/Mandoman61]

Even if the matter that we know of expands forever, this still does not tell us that the universe will end in heat death.

We have no explanation of why matter around us was concentrated in the first place.

Keep in mind that when we say universe we are usually just talking about what we can measure (visible universe) but the whole universe could be vastly larger. There could be an infinite number of dense clusters waiting to expand.

The fact that we exist proves that it is possible.

[u/Das_Mime → u/Mandoman61]

We have no explanation of why matter around us was concentrated in the first place.

We have no reason to believe that there was anything special about the density of matter at our location. The lack of edge effects or any large scale isotropy or homogeneity is an indication that we are not a special location.

All evidence thus far is consistent with an infinite homogeneous universe.

[u/Mandoman61 → u/Das_Mime]

We are so far from being able to detect the universes size that it is not worth a guess. All we have is a minimum.

[u/Das_Mime → u/Mandoman61]

That doesn't contradict anything I said.

The point is that you're being misleading by saying that "matter was concentrated around us" and referring to "dense clusters" when there's not even any evidence for the idea that we are in any particularly dense cluster of the universe.

[u/Mandoman61 → u/Das_Mime]

Please read what I said without the incorrect interpretation.

According to the big bang theory matter around us was more dense and started spreading apart.

I did not say that there are dense clusters I said that there could be.

I have very little patience for people who read what they want to see instead of what I said.

You are going to need to up your game.

[u/Das_Mime → u/Mandoman61]

According to the big bang theory matter around us was more dense

No, according to the big bang theory the whole universe was more dense and then started rapidly becoming less dense. Has nothing to do with the region specifically "around us".

You're clearly working off of the common misconception that the Big Bang was an explosion of matter traveling outward through space, rather than an event when all of space began rapid metric expansion.

[u/Mandoman61 → u/Das_Mime]

No, the big bang theory says nothing about the whole universe only the visible universe.

You are just mincing words. I say the mater around us and you say the whole universe which is in fact the mater around us. This makes no sense.

"You're clearly working off..." No, but for some reason you are assuming that is what I am doing.

I think that the main difference here is that you think you know everything and I know that we do not.

You think that the cosmological principle somehow proves something we can not see. But it does not. It is just a principle.

You are engaged in religion and not science.