As someone who doesn’t know much about this, I'm curious:
If humanity survived far into the future, could we plausibly develop ways to slow or even halt the decay of the universe? Or is this an immutable characteristic of our universe, meaning humanity will inevitably fizzle out along with the universe?
I’m not an expert on this, but I read this by Lawrence M Krauss (theoretical physicist and cosmologist):
“In 5 billion years, the expansion of the universe will have progressed to the point where all other galaxies will have receded beyond detection. Indeed, they will be receding faster than the speed of light, so detection will be impossible. Future civilizations will discover science and all its laws, and never know about other galaxies or the cosmic background radiation. They will inevitably come to the wrong conclusion about the universe......We live in a special time, the only time, where we can observationally verify that we live in a special time.”
A billion is just 10 to the power of nine, and that number of years in time is itself a long, long time that’s difficult to imagine. Looking at 10 to the power of 78 is…it wouldn’t matter much for us if it were to the power of 60 either. (I think!) I seriously doubt humans (as we know of now) can meaningfully affect the expansion or decay of the universe.
In just 5 billion years? This surprises me, trillion I could understand, 5 billion is similar to the age of the earth.
Incidentally, the obvious counter to "our time is special, we have access to everything" is presumably what future civilisations think as well; the implication being perhaps we have lost something over the aeons that would shed light on our current mysteries.
I haven't read the book but it's an unconvincing extract, though I acknowledge a larger context may justify it.
Someone made a miscalculation with 5 billion years, but with that said, it's only just over an order of magnitude more which isn't much
>And what are presently the closest galaxy groups outside of the Local Group — objects like the M81 group — will be the last to become unreachable: something that won't occur until more than 110 billion years from now, when the Universe is nearly ten times its present age.
Maybe there was a self-conscious "civilization" before the big bang. From my understanding we know very little to nothing about anything before the big bang.
Unless you believe that this universe is just playing out holographic on the event horizon of an N+1d black hole in our parent universe. The Big Bang was just the singularity birth of that one object.
Except not all dimension numbers have nicely defined physics and geometries. For example, 4+0 and 4+1 don't have symmetric pairwise particle interactions in the sense we have in 3+1.
Can you provide the source for that quote? 5 billion years seems way too soon.
The Hubble constant is currently approximately one doubling per 14 billion years [1]. So 5 billion years isn't enough to double the recession speeds. AFAIK there's plenty of galaxies receding at less than half the speed of light. Wikipedia estimates 150 billion years (6000x expansion) for all but the local group to be beyond the horizon [2]. So your quote seems to be off by two orders of magnitude.
Right so we're limited in time and resources, in a sense. Only some of the universe would be reachable within those 10^1100 or 10^78 years anyway. So we are limited by time but also what we can access.
What's fascinating to me is to consider the frontier of galaxies theoretically reachable within a given window, and the potential race to colonize them before they race away.
Well, the rest of us will likely die. However, you (the reader of this comment) will only have observed universes in which you don’t die. So, due to quantum immortality and all that, you’ll figure it out I guess. And in some sense humanity will not fizzle out; at least you’ll carry it along.
It is a big project, but don’t worry, you’ve got quite a while to work it all out. I would start working on it in earnest in about a million years. If you wait a couple billion, more of the stuff in the universe might have decayed, and the end result might be less interesting, I guess.
Please tell whatever else is around about the rest of us!
Time is irrelevant. What matters are units of computations.
When things are predictable they can be simulated fast : A spinning ball in the void can be simulated for 10^78 years in O(1).
When things are fuzzy, they can be simulated fast : A star made of huge number of atoms is not so different than another star made of a huge number of atoms. When processes are too complex they tend to all follow the law of large numbers which makes the computations memoizable.
What you want is a way to prevent the universe from taking shortcuts in its computations. Luckily its quite easy. You have to make details important. That's where chaos theory comes to the rescue. Small perturbations can have big impacts. Bifurcations like tossing a coin in the air create pockets of complexity. But throw too many coins in the air and its just random and boring. Life exists on this edge where enough structure is preserved to allow enough richness to exist.
One way humans have found of increasing precision is the lathe, which lead to building computers. Build a big enough fast enough computer and you will run-out of flops faster than reaching the 10^78 endgame.
But you have to be smart, because computation being universal it means that if you are just building a big computer what matters will be what runs on it. And your universe can be reduced to a recursive endgame state of "universe becoming a computer running universe simulation of a specific type", which doesn't need to computed more than once and already was, or isn't interesting enough to deserve being computed.
That's why we live on the exciting edge before the Armageddon, boring universes having already been simulated. The upside being universe hasn't yet decided which endgame we may reach, because the phytoplankton aliens of k2-18b have not yet turned on their supercomputer.
If we survive far into the future, we will learn a lot more about the structure and evolution of the Universe. It might be that the questions that our scientists can ask now will turn out to be trivial or meaningless to our descendants. Perhaps the Universe is far stranger than we can imagine.
While it seems doubtful that people will last that long, in 10^78 years, one would think those people alive at the time would want the universe to continue.
Agreed. It is so highly unlikely that the probability is effectively zero.
Let's give everyone the benefit of the doubt and assume that humanity can exist a thousand times longer than your estimate, say 3x10^9 years. That's about as long as we think life has existed on earth, which is a VERY LONG TIME. That said, it's still 1 x 10^-69 of that time period. I think you can see where we're going with this.
No offense intended, but I have a serious question:
Why would you hope this? This hope seems to me a vestige of the desire of some humans for immortality. And why would it matter to folks whether some sort of intelligence existed this incomprehensibly far into the future?
I think a bigger question is what will they do for that long?
All the things like stars will be long gone and dead before that time leaving us with long lived black holes and radiation. So everything would be based on virtual world can computation by that point. Do you just cool everything to near absolute zero and run it as slow as possible to you can last as long as possible?
The History of the Universe channel has an episode around this, but I'll have to figure out which one it was.
Here's some food for thought: there are perhaps some things that would be perhaps out of reach for all living beings for the conceivable future and beyond.
We are barely able to handle technological progress that would seem like stone age or even worse to a potential species that may exist at that time (ie those that may have such technology to stop the death of the very universe they are living)
They might just be indistinguishable from a god if there is one. And if they have enough power to perhaps prevent the death of the universe, they might have enough technology to just recreate another one. Or open a wormhole and transport to a new one or travel the multiverse or something.
Basically I feel if such kind of technology can be created to bend the universe to your will, it would be misused so badly, it might be catastrophic for the existence of such a species.
Hawking radiation is a very slow process; one can acquire additional matter (e.g., hydrogen atoms from interstellar or intergalactic space) to compensate for the matter loss
If humanity survived far into the future, could we plausibly develop ways to slow or even halt the decay of the universe? Or is this an immutable characteristic of our universe, meaning humanity will inevitably fizzle out along with the universe?