I appreciate your optimism. I tend to be optimistic about the future myself. But there is no law of the universe that everything will work out ok. Only if we make the right decisions as a species and we don't get unlucky.
I'm quite apprehensive that the great filter lies ahead - that technology accelerates too rapidly compared to our wisdom and we end up nearly destroying ourselves. We're getting the ability to program life itself and to likely to democratize the ability to harness the forces inside the atom. Neither of which we're ready for as a species.
Maximum entropy merely implies that the temperature everywhere is the same (any other situation would necessarily have a lower entropy). You could in theory have maximum entropy at 1000K. Our universe has a ton of empty space, and not all that much energy, so the temperature at which it equilibriates is very low. It's also expanding, so the hypothetical equilibrium temperature is decreasing all the time.
It's also worth noting that the entropy can be very large, even if the temperature is absolute zero. (You just need a system with a lot of different ground-states that all have the same energy.)
> I appreciate your optimism. I tend to be optimistic about the future myself. But there is no law of the universe that everything will work out ok.
Isn't there some QM law that says that with infinitesimal probability anything can materialize at any point in space? Meaning that after everything has collapsed, you can (will!) still re-materialize somewhere in space. An infinite number of times!
I kind of wonder, in a half-assed amateurish way, if the underlying reality of our universe isn't just an extremely rare random fluctuation in a fluid-like medium at thermodynamic equilibrium.
There are multiple explanations for why the sky isnt lit up with radio and laser signals from advanced civilisation. The great filter is one explanation, that there are existential crises or threats that wipe out most civilisations or cause them to collapse to subsistence level. Nuclear war, biological weapons, ecological collapse, paper clip maximising AI, etc.
I once ran a Traveller RPG exploration campaign where one of the systems they visited looked really odd on sensors. Just fuzzy clouds and clumps and ring formations of diffuse metallic debris. It turned out it was all paper clips.
For context, the examples you mentioned are cases of the great filter lying ahead of us. The more optimistic hope is that the great filter is behind us - things like abiogenesis or multicellular life being extremely unlikely to happen. "Great filter" is just the name for "a barrier that stops life from becoming a spacefaring civilization".
This explanation is also the reason why finding basic life (say, bacteria) in the Solar System would be a cause for worry - if life evolved independently twice in the same star system, it would imply abiogenesis isn't that unlikely - thus strongly suggesting the great filter is still ahead of us.
Could the great filter be something like developing language? That's something that seems quite rare (only one species on Earth has it). If so, then discovering bacteria in the Solar System wouldn't be such a cause for worry.
> The Big Freeze (or Big Chill) is a scenario under which continued expansion results in a universe that asymptotically approaches absolute zero temperature.
The worry is that not only will we be utterly destroyed, but that the destruction will be so thorough it will blow backward through time erasing all events that ever happened and making it so that we never even lived. That means everything we experience right now didn’t happen, we are just seeing a probability of what could happen but didn’t because it’s all destroyed. These lives mean nothing.
Imagine they told you that when you die, not only will you be gone, but then they will go back and undo everything you ever did and basically make it like you never existed at all. It didn’t happen, you never happened.
It happened, therefore it happened somehow, someplace. What’s the difference between something having happened and not having happened? It doesn’t intrinsically mean anything.
In addition, most humans learn to accept that there’s a good chance nothing they do will have an eternal effect on reality without needing any strange frameworks.
"The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every ‘superstar,’ every ‘supreme leader,’ every saint and sinner in the history of our species lived there-on a mote of dust suspended in a sunbeam" - Carl Sagan
And that pale blue dot means nothing in a cosmic scale. Stop worrying and enjoy the incredible fortune of being alive.
Why? What exactly are you dreading? That our understanding of the universe and science involved might have some serious flaws? If so, won't we just adjust our understanding to something that matches the observations?
Don't worry it will be a problem for the future politicians and universe expand protections groups. "We have to stop the universe expansion, the universe is expanding faster than expected" they say.