[HN Gopher] Universe expected to decay in 1078 years, much soone...
       ___________________________________________________________________
        
       Universe expected to decay in 1078 years, much sooner than
       previously thought
        
       Author : pseudolus
       Score  : 155 points
       Date   : 2025-05-12 09:46 UTC (13 hours ago)
        
 (HTM) web link (phys.org)
 (TXT) w3m dump (phys.org)
        
       | Etheryte wrote:
       | So Hawking radiation moves the estimate from the previous 10^1100
       | to 10^78 years. That's a pretty drastic change, but naturally,
       | not exactly something to go and worry about. Most of us would be
       | lucky to make it to 10^2, so there's still some way to go.
        
         | busyant wrote:
         | get your affairs in order.
        
         | coolcase wrote:
         | Another 10^3 would be good for humanity
        
         | lordfrito wrote:
         | The exponent going 1100 to 78 is pretty large error... huge 93%
         | reduction... hopefully they have high confidence in the new
         | value, otherwise humanity might be looking at 1 more big
         | problem this century.
        
           | immibis wrote:
           | It's actually a 99.999999999999999999999999999999999999999999
           | 9999999999999999999999999999999999999999999999999999999999999
           | 9999999999999999999999999999999999999999999999999999999999999
           | 9999999999999999999999999999999999999999999999999999999999999
           | 9999999999999999999999999999999999999999999999999999999999999
           | 9999999999999999999999999999999999999999999999999999999999999
           | 9999999999999999999999999999999999999999999999999999999999999
           | 9999999999999999999999999999999999999999999999999999999999999
           | 9999999999999999999999999999999999999999999999999999999999999
           | 9999999999999999999999999999999999999999999999999999999999999
           | 9999999999999999999999999999999999999999999999999999999999999
           | 9999999999999999999999999999999999999999999999999999999999999
           | 9999999999999999999999999999999999999999999999999999999999999
           | 9999999999999999999999999999999999999999999999999999999999999
           | 9999999999999999999999999999999999999999999999999999999999999
           | 9999999999999999999999999999999999999999999999999999999999999
           | 9999999999999999999999999999999999999999999999999999999999999
           | 9999999% reduction and yes that is the correct number of 9's.
        
             | stirlo wrote:
             | Yep the difference between 10^78 and 10^1100 is
             | approximately 10^1100...
        
       | wewewedxfgdf wrote:
       | Despite it being quite a way out it's still a little sad to think
       | the end is coming.
        
         | rswail wrote:
         | "quite a way out"... is doing a lot of work in that sentence.
        
       | keepamovin wrote:
       | Aw fuck, I was looking forward to curing a few more deaths and
       | bringin the Bitchun Society to yet more barbarian tribes in the
       | outer reaches. I wonder if my whuffie will last that long? I
       | really don't want to deadhead so hopefully there's plenty more
       | interesting things to do in the tail end.
        
         | aspenmayer wrote:
         | > whuffie
         | 
         | I started to read this book, but never finished it, but the
         | whuffie idea has legs. Stuck with me longer than many ideas
         | from books I did finish. Need to pick it up again.
         | 
         | https://en.wikipedia.org/wiki/Down_and_Out_in_the_Magic_King...
        
       | tobias_irmer wrote:
       | To me that still sounds like forever.
        
       | MOARDONGZPLZ wrote:
       | I hope they're working on finding a way to massively decrease the
       | net entropy in the universe after this.
        
         | andreareina wrote:
         | Unfortunately there is as yet insufficient data for a
         | meaningful answer
        
           | watt wrote:
           | Crack on with it and don't keep us in the dark!
        
         | coolcase wrote:
         | The way to do that is to do the most unlikely things
        
       | dvh wrote:
       | > Previous studies, which did not take this effect into account,
       | put the lifetime of white dwarfs at 10^1100 years
       | 
       | That's some kind of typo no? I've only heard previous estimates
       | for white dwarf to be trillions of years, that is significantly
       | shorter that 10^1100
       | 
       | Edit: never mind, by lifetime that me proton decay, not how long
       | they shine light
        
       | vijaybritto wrote:
       | My shower is theory is that there are infinite universes getting
       | created all the time and we can never know about it because we're
       | restricted in this universe. I love having these talks with my
       | daughter.
        
         | Y_Y wrote:
         | There's a teapot orbiting the sun between Earth and Mars too.
        
         | A_D_E_P_T wrote:
         | That's almost the mainstream position in physics as of 2025 --
         | that cosmic inflation never stopped, that it produces universes
         | beyond number, and we're in one pinched-off region of it.
         | 
         | You'd like this book:
         | https://mitpress.mit.edu/9780262547222/an-infinity-of-worlds...
        
         | hinkley wrote:
         | The trouble would be that even if we sensed other universes we
         | might not be able to go there unless we can create our own
         | pocket universes. There's no guarantee that an adjacent
         | universe has the same rules of physics.
         | 
         | All of the enzymes in your body might stop working if you
         | stepped into even a slightly different universe. You could just
         | turn into a gas, and not in a good way.
        
       | m1117 wrote:
       | AI is going to take over anyways
        
         | coolcase wrote:
         | It'll be 42'd like everything else
        
       | Aetheridon wrote:
       | so i wonder what comes after?
        
         | willis936 wrote:
         | A fun tool to think around such things are Penrose diagrams.
         | Personally I'm a little dubious of strong claims of what will
         | happen in the distant future since we have such incomplete
         | models of physics today. It takes GUTs to predict the future.
         | 
         | https://youtu.be/mht-1c4wc0Q
        
         | voidUpdate wrote:
         | The Credits
        
         | Lerc wrote:
         | If there is nothing left, does time pass? Does it pass but is
         | meaningless? Does it no longer exist?
         | 
         | The same question goes for space. Is there any size to the
         | nothingness? To go further when you have notions like
         | inflation, can you have nothing that is increasing in volume?
         | That would suggest a change in state an thus a sense of not yet
         | ended.
         | 
         | It would be a weird thing for nothingness to change state. It
         | seems like fertile soil for sci-fi. Imagine if space itself was
         | kind of Turing complete and once the noise of matter ended it
         | could start the real work, which of course would be simulating
         | the next universe.
        
           | coolcase wrote:
           | There is a theory out there that once heat death is done
           | distance is meaningless, therefore zero, therefore big bang
           | again.
        
             | Lerc wrote:
             | That was kind of my intuition as well, similarly for time,
             | if there was no distinction between long and short amounts
             | of time, an instant would be the same as eons. If the big
             | bang was improbable but possible it would just happen. The
             | fact that we are here is suggestive that is possible.
        
             | laxd wrote:
             | Conformal cyclic cosmology, by Roger Penrose
        
               | coolcase wrote:
               | I think that's it. Ad a layman I don't understand how the
               | final transition (final hawking radiation) then tells the
               | rest of the universe "I'm done" similar to a sprint
               | retro!
        
           | mr_toad wrote:
           | > It would be a weird thing for nothingness to change state.
           | 
           | If there are no physical laws, there's nothing to stop that
           | happening.
        
         | rswail wrote:
         | That question makes no sense in terms of this discussion. The
         | heat death of the universe means that there is no "after", just
         | as there was no "before" the Big Bang.
         | 
         | The actual concept of time does not exist (at least in my
         | humble year 12 physics understanding and having read Brief
         | History Of Time a long time ago :) )
        
           | kergonath wrote:
           | > having read Brief History Of Time a long time ago :)
           | 
           | It pains me to say this, because it is a masterpiece of
           | vulgarisation, putting arcane physics and cosmology within
           | reach of (still decently-educated) normal people, but it is
           | very outdated in a lot of respects. It badly needs something
           | else.
           | 
           | I found some of Carlo Rovelli's books to be quite compelling,
           | but they are more focused on the topic of time and space-
           | time. Not really the universe in the same way as Hawking's
           | were.
        
       | blueflow wrote:
       | It is written                 The researchers calculated that the
       | process of Hawking radiation theoretically also applies to other
       | objects with a gravitational field
       | 
       | but: doesn't this only apply if these objects if they have some
       | sort of decay process going on? There are nuclides that have
       | never been observed decaying. I would expect a white dwarf to
       | burn out, go through radioactive decay (unstable nuclides ->
       | stable ones) and end up as inert rock (stable nuclides) at
       | background temperature.
        
         | dist-epoch wrote:
         | Regular "stable nuclides" stuff which falls into a black hole
         | gets spit out as Hawking radiation, so no, this is a
         | gravitational process, radioactive decay is a standard model
         | one.
        
         | jfengel wrote:
         | Hawking radiation doesn't require decay. Pairs of particles
         | appear spontaneously. One falls into the gravitational field,
         | losing energy.
         | 
         | The net energy loss comes from the gravitational field of the
         | object, and its mass decreases. We don't have details on just
         | what that means at a Standard Model level, but the net loss of
         | energy means something is going to disappear even without any
         | kind of previously understood decay.
        
           | dist-epoch wrote:
           | > Pairs of particles appear spontaneously. One falls into the
           | gravitational field, losing energy.
           | 
           | That's not really true. Even Hawking admitted that's it's a
           | simplification he did for his popular science book of what
           | really is going on.
           | 
           | https://www.youtube.com/watch?v=UxVssUb0MsA
        
             | leptons wrote:
             | Hawking never knew "what really is going on". He wrote some
             | nice hypotheses, but he never knew for sure, and was not
             | ever close to knowing.
        
               | MattPalmer1086 wrote:
               | But he did know the simplification was wrong.
        
         | mr_toad wrote:
         | No, all objects with non-zero temperature radiate heat. Stars,
         | white dwarfs, black holes, even the universe itself.
        
           | blueflow wrote:
           | I said                 inert rock at background temperature
           | 
           | so radiated and absorbed heat should already be accounted
           | for, right?
        
         | pixl97 wrote:
         | >here are nuclides that have never been observed decaying
         | 
         | Aren't we pretty sure due to things like quantum tunneling that
         | the probability of any quantum particle existing trends to zero
         | given a long enough time?
        
         | cvoss wrote:
         | The whole point of Hawking radiation is that a thing which
         | famously shouldn't have a decay process (a black hole) in fact
         | does have a decay process due to the interaction of gravity and
         | quantum mechanics.
        
       | terabytest wrote:
       | 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?
        
         | saberience wrote:
         | See The Last Question, by Isaac Asimov:
         | 
         | https://users.ece.cmu.edu/~gamvrosi/thelastq.html
        
           | Vox_Leone wrote:
           | It's interesting to note, that the Universal AC in "The Last
           | Question" did not hallucinate an answer.
           | 
           | Instead, its response--"INSUFFICIENT DATA FOR MEANINGFUL
           | ANSWER"--is a model of intellectual honesty.
        
         | mykowebhn wrote:
         | Why, so we can extend the 10^78 years? I'm not sure you truly
         | understand how large 10^78 years is, or even 10^10 years.
        
           | suddenlybananas wrote:
           | 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.
        
             | bbarnett wrote:
             | Imagine if we solve it. Then hope to preserve the answer
             | long enough, that people will care.
             | 
             | The first problem is data integrity and storage. Will the
             | atoms the answer is on, still be around?
             | 
             | The next is, what kind of search engine will we have, with
             | 10^78 years of internet history?!
        
               | pixl97 wrote:
               | 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.
        
               | bbarnett wrote:
               | They'll exist because of Wan-To.
               | 
               | The World at the End of Time by Frederick Pohl.
        
             | rswail wrote:
             | Humanity has existed for 3x10^6 years (give or take), which
             | is 1 x 10^-72 of that time period.
             | 
             | We don't need to worry, it is highly unlikely that humanity
             | as we recognize it will exist.
        
               | mykowebhn wrote:
               | 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.
        
               | cdelsolar wrote:
               | it won't be humanity, but it should hopefully be some
               | sort of intelligence
        
         | diego898 wrote:
         | Very strongly suggest you check out Isaac Asimov's "The Last
         | Question"
         | 
         | https://users.ece.cmu.edu/~gamvrosi/thelastq.html
        
           | brazzy wrote:
           | Or, for an alternative and rather more in depth treatment,
           | Stephen Baxter's "Manifold: Time"
        
         | krapp wrote:
         | The Second Law of Thermodynamics is an immutable characteristic
         | of our universe. Entropy in a closed system (like the universe)
         | is irreversible.
        
           | exe34 wrote:
           | It was set to zero once, so somebody somewhere/somewhen
           | figured it out before.
        
             | WhatsName wrote:
             | Or rather we are a fork/thread somewhere is spacetime.
        
               | VagabundoP wrote:
               | git branch
        
             | krapp wrote:
             | lolwut?
        
         | felipeerias wrote:
         | 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.
        
           | ashoeafoot wrote:
           | The origami of petal unfolding implies the rose blooms
           | forever says all bugkind dwelling on the bud.
        
         | AnonC wrote:
         | 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.
        
           | mellosouls wrote:
           | 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.
        
             | pixl97 wrote:
             | 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.
        
             | andruby wrote:
             | 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.
        
               | generic92034 wrote:
               | If the big bang created space and time, "before the big
               | bang" is not really well-defined.
        
               | kridsdale1 wrote:
               | 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.
        
               | generic92034 wrote:
               | From inside that universe there still was no "before".
               | Are you looking into our universe from the outside? ;)
        
           | glenstein wrote:
           | 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.
        
           | analog31 wrote:
           | This is a good reason not to throw away your old textbooks.
        
           | isoprophlex wrote:
           | Is that right? Only 5 billion years until noone sees the
           | background radiation and other galaxies?!
           | 
           | That's... awe inspiring.
        
             | ChrisClark wrote:
             | That seems relatively soon! I know it's a huge number, but
             | on universal scales, that's crazy
        
           | Strilanc wrote:
           | 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.
           | 
           | [1]: https://astronomy.stackexchange.com/questions/49248/inte
           | rpre...
           | 
           | [2]: https://en.wikipedia.org/wiki/Timeline_of_the_far_future
        
             | xdennis wrote:
             | > Can you provide the source for that quote? 5 billion
             | years seems way too soon.
             | 
             | Yeah, seems off. According to Wikipedia it's 2 trillion
             | years[1] until galaxies outside the Local Supercluster
             | become undetectable.
             | 
             | [1]: https://en.wikipedia.org/wiki/Future_of_an_expanding_u
             | nivers...
        
           | unsupp0rted wrote:
           | Which leads one to wonder what phenomena we were too late to
           | observe and which of our assumptions are therefore faulty
        
         | bee_rider wrote:
         | 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!
        
         | GistNoesis wrote:
         | 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.
        
           | TOGoS wrote:
           | This is a wacky, seemingly out-of-place philosophical
           | comment, yet I have had similar thoughts, so I give you an
           | irreverent upvote.
        
         | thatguymike wrote:
         | There's a very entertaining Dwarkesh podcast with Adam Brown
         | about this: https://www.dwarkesh.com/p/adam-brown
        
         | mensetmanusman wrote:
         | Humans are the universe contemplating this.
        
         | BurningFrog wrote:
         | The only serious answer is that we have absolutely no way of
         | knowing that.
        
       | Extropy_ wrote:
       | This is the original paper: https://arxiv.org/abs/2410.14734
       | 
       | They say their findings set "a general upper limit for the
       | lifetime of matter in the universe."
        
       | fsiefken wrote:
       | Ok, well, surviving beyond 1 billion years and various extinction
       | level events, asteroids, comets, nuclear wars, are are the first
       | priority, we'll worry about this later.
       | 
       | Perhaps we can set up a secret program where AI randomly selects
       | individuals based on merit, character to get the latest in life
       | extension treatments, philosophical and spiritual education so
       | they can guide us (with AI assistence) into the future and beyond
       | the solar system.
       | 
       | If we survive, 'we' most probably don't exist by that time in any
       | recognisable shape or form.
        
         | NoMoreNicksLeft wrote:
         | I suspect we have more immediate problems than "can we survive
         | the next n billion years".
        
           | 2OEH8eoCRo0 wrote:
           | There have already been close calls with nukes. No way in
           | hell we last another hundred.
        
             | NoMoreNicksLeft wrote:
             | If only it was nukes. I'm afraid we're more likely to go
             | out with a whimper. The fertility rates have plummeted and
             | there's no reason to believe those will rise back to
             | replacement level.
        
         | rTX5CMRXIfFG wrote:
         | What values do you think we should optimize for?
        
       | Ygg2 wrote:
       | Good. Maybe now they can prove Hawking radiation in something
       | that isn't a bath tub. Or an oven.
        
       | Ekaros wrote:
       | One more argument not to do anything about climate change. After
       | all universe is going decay shortly...
        
       | thom wrote:
       | Ah, just time for another bath. Pass me the sponge somebody, will
       | you?
        
       | andrewstuart wrote:
       | How can the universe come from an infinite point and have no
       | Centre.
        
         | acuozzo wrote:
         | The center is everywhere.
        
         | laxd wrote:
         | Imagine blowing up an infinitesimally small balloon. Nowhere on
         | the surface will you find the center. Also, as the other
         | comment says, the center is everywhere. We are on the inside of
         | the big bang.
        
       | stavros wrote:
       | Oh no! What are we going to do about this?
        
       | maaaaattttt wrote:
       | I suppose this time is expressed in earth years? Or what would
       | this duration mean on a Universe scale? Also given the nature of
       | space-time (the time and gravity relationship) wouldn't time be
       | almost still once, let's say, year 1077 is reached?
        
         | pixl97 wrote:
         | Isn't time relative?
         | 
         | If you were in a place where time was still you'd have no idea
         | it were the case. Time would still tick at one second per
         | second. You could only tell when you looked at some other
         | object/patch of space that had a different ticking clock.
        
       | rswail wrote:
       | People will be gathering at the Restaurant At The End Of the
       | Universe with Douglas Adams as the host.
        
       | chasing wrote:
       | Probably on a Thursday. I never could get the hang of Thursdays.
        
       | octocop wrote:
       | the term "sooner" in this case is, you know, relative
        
       | jmclnx wrote:
       | >Because the researchers were at it anyway, they also calculated
       | how long it takes for the moon and a _human_ to evaporate via
       | Hawking-like radiation. That 's 10^90 years.
       | 
       | Well I can predict the next trend, launching very rich people's
       | body into space so it will last 10^90 years :)
        
         | pixl97 wrote:
         | Depends what you mean by last.
         | 
         | Over periods of time that long it's much more likely you'll run
         | into some other object, say fall into a gravity well or
         | something like that.
         | 
         | Even if you don't, pure erosion from neutral hydrogen and space
         | dust will have disintegrated your capsule long before then.
        
       | JohnMakin wrote:
       | Bad news for Boltzmann brains
        
         | matheusd wrote:
         | Is it though? It is my understanding that the quantum
         | fluctuations that give rise to BBs will still exist, even after
         | (and specially after) the evaporation of black holes (perhaps
         | assuming no Big Rip).
        
           | JohnMakin wrote:
           | It's just a joke but the average number of years for a
           | spontaneous quantum fluctuation to produce a boltzmann brain
           | was calculated at something like 10^500 years. You're right
           | that the processes involved would still remain barring some
           | kind of big rip event.
        
             | squigz wrote:
             | Does this mean such an event could produce, say, an entire
             | universe?
             | 
             | If so, does this theoretically mean that a cyclic universe
             | is possible in this way, and that if one were to go far
             | enough - impossibly, unfathomably far - you might find the
             | remnants of other universes?
        
               | immibis wrote:
               | The theory of Boltzmann brains is that you're way more
               | likely to get just a brain (including false memories of a
               | planet earth and a whole visibile universe around it),
               | than to get a brain, a planet earth, and a whole visible
               | universe around it. So the chance that any of that is
               | real, given that a brain exists to perceive it, is
               | infinitesimal. We are probably just floating human brains
               | that popped into the vastness of space three microseconds
               | ago, complete with false memories of the distant past.
               | 
               | To dispel a misconception: They're not some hypothetical
               | type of brain that exists as pure quantum fluctuations
               | (though those are _even more_ likely). Boltzmann was
               | talking about the probability of actual flesh-and-blood
               | human brains arising spontaneously out of the vacuum.
        
               | simonh wrote:
               | Wouldn't the vast majority of those be incoherent broken
               | messes, of various levels of inconsistency? Only a teeny
               | tiny fraction would be coherent. So the expected
               | experience fir any arbitrary Boltzmann brain would be all
               | over the place.
        
           | x1000 wrote:
           | Not a physicist, but I see it this way too. My understanding
           | of Boltzmann brains is that they are a theoretical
           | consequence of infinite time and space in a universe with
           | random quantum fluctuations. And that those random
           | fluctuations would still be present in an otherwise empty
           | universe. So then this article has no bearing on the
           | Boltzmann brain thought experiment or its ramifications.
        
           | layer8 wrote:
           | They may not actually happen:
           | https://arxiv.org/abs/1505.02780
        
       | dan_can_code wrote:
       | Damn. That ruins my retirement plans
        
         | bdangubic wrote:
         | just in time for your 401k to recover :)
        
       | KingOfCoders wrote:
       | One of my favorite Wikipedia pages
       | 
       | https://en.wikipedia.org/wiki/Timeline_of_the_far_future
        
         | lattalayta wrote:
         | In video form: https://www.youtube.com/watch?v=uD4izuDMUQA
        
           | tarsius wrote:
           | For dramatic effect, my monitor turned off right after "By
           | this point, distant galaxies and starts are receding so fast
           | that their light has become undetectable."
        
           | rwoerz wrote:
           | My favourite sleep aid video.
        
         | VagabundoP wrote:
         | Here's my favorite youtube version of this:
         | 
         | https://youtu.be/uD4izuDMUQA
        
         | thih9 wrote:
         | > in 10k years (...) the average length of a solar day will be
         | 1/30 of an SI second longer than it is today.
         | 
         | Looks like a new test case scenario for libraries that handle
         | time/date.
        
           | Timon3 wrote:
           | Am I misreading something, or isn't that already in 1,000
           | years?
        
             | thih9 wrote:
             | You are correct, I made a typo in the grandparent comment -
             | it should have been 1k years. Unfortunately I can no longer
             | edit.
        
           | timewizard wrote:
           | Insertion of a leap second every month.
        
         | slicktux wrote:
         | Great wiki page! It even mentions Boltzmann Brains! " This
         | infinite future could allow for the occurrence of massively
         | improbable events, such as the formation of Boltzmann brains."
        
         | paulpauper wrote:
         | So given these finding, that page will need to be overhauled a
         | lot
        
         | burnt-resistor wrote:
         | To survive beyond 1 Gy from now, life will need to move
         | underground where the water is and hopefully much cooler than
         | the eventual surface. Also, such life may/will become necessary
         | to relocate to Mars, hopefully taking resources with them. (I
         | don't say "us" because of likely dramatic evolution.)
        
         | evtothedev wrote:
         | I feel like you could build an entire meditation practice
         | around reading this article.
        
           | azemetre wrote:
           | That or existential dread.
        
         | NKosmatos wrote:
         | It pairs well with
         | https://en.wikipedia.org/wiki/Ultimate_fate_of_the_universe
        
         | grues-dinner wrote:
         | If Reid Malenfant or Jim Bolder aren't involved, this isn't the
         | deep time future I'm interested in.
        
       | mediumsmart wrote:
       | so many years - and how many miles?
        
       | belter wrote:
       | Did Broadcom acquire this Universe?
        
       | IamLoading wrote:
       | If humans end up existing at 10^77 years. You would hope and
       | imagine that they would be prepared for the decay?
        
         | recursive wrote:
         | Well, that's only 10% of the way there, so they'd still have
         | most of the time left.
        
           | hinkley wrote:
           | Let the grandkids worry about it. Now would you be a pal and
           | hand me another another atomic mimosa?
        
             | recursive wrote:
             | It would be the great-great-great-... Actually, there
             | aren't enough electrons in this system to encode all the
             | great-s needed to express the name of the generation.
             | 
             | I'm all for thinking of the children, but planning at that
             | range is probably impossible.
        
         | hathym wrote:
         | with what's going on, not sure if human will exist in the next
         | 10 years
        
       | foobarkey wrote:
       | My pet theory: all atoms decay back to hydrogen given enough
       | time, gravity pulls them together, stars form, the universe is
       | one big loop that self resets :)
        
         | ewzimm wrote:
         | You're in good company. Something similar, minus the hydrogen
         | phase, is proposed by Roger Penrose:
         | https://en.wikipedia.org/wiki/Cycles_of_Time
        
           | 6gvONxR4sf7o wrote:
           | I went to a talk of his on CCC ages ago, and it was such a
           | fascinating combination of geometry, causality, and
           | asymptotics. I have absolutely no clue whether it's
           | reasonable physically, but independent of that, it's just a
           | really elegant fusion of topics in a fun to think about way.
           | Worth a read for anyone who just appreciates elegant new ways
           | of combining mathematical structures.
        
           | mensetmanusman wrote:
           | Apparently time ceases when absolutely all mass is gone,
           | because mass is required for a clock.
           | 
           | This of course requires the decay of protons.
        
             | MattPalmer1086 wrote:
             | Why would time cease because all the measuring devices were
             | gone?
        
               | sourdoughness wrote:
               | My understanding of this idea is that once the universe
               | reaches a state of maximum entropy (this is the "heath
               | death" of the universe, where everything is a uniform,
               | undifferentiated cloud of photons, then time stops being
               | meaningful because there can be no change from moment to
               | moment. In a sense, time _is_ the change from low to high
               | entropy - if you don't have any entropy gradient, you
               | can't have any time either.
        
         | HideousKojima wrote:
         | My pet theory:
         | 
         | The Big Bang happened at the "north pole" of spacetime.
         | Eventually all matter and energy will reach the "south pole"
         | and recombine. The Big Crunch theory will never die!
        
           | vlovich123 wrote:
           | The big bang happened at the center of the universe and every
           | point of space is the center of the universe at all times.
           | You could argue that the center of spacetime is
           | definitionally the Big Bang since that's when time is
           | believed to have started to exist in the first place but we
           | don't have a good grasp of how to define the center of a 4D
           | physical structure where one dimension is time which doesn't
           | seem to really act like the other dimensions.
        
             | hinkley wrote:
             | Are you saying you're the center of the universe?
        
         | layer8 wrote:
         | The evidence about the accelerating expansion of the universe
         | would seem to contradict that theory.
        
           | vlovich123 wrote:
           | Not necessarily.
           | 
           | A) We don't know if all derivatives are >= 0. e.g. if the
           | jerk rate is < 0, then you'd expect contraction eventually.
           | Similarly, if the derivative of the jerk rate is < 0 & so on.
           | So even accelerating expansion could eventually lead to
           | contraction.
           | 
           | B) We don't have a lot of very highly compelling evidence
           | that the universe is actually accelerating (at least nowhere
           | like we do for the Big Bang). For example, alternate models
           | have proposed that our apparent perception of the expansion
           | is simply as a result of the effect of non-uniform gravity
           | throughout the universe & that the vaccuum of space between
           | galaxies has even less time dilation and that's what make it
           | look like things are expanding.
           | 
           | In other words, I'd put the model of a permanently expanding
           | universe as less likely to actually match reality.
        
         | chasil wrote:
         | The proton itself that forms the hydrogen atom might decay (we
         | don't know yet; we do know that neutrons decay after 15
         | minutes).
         | 
         | https://en.wikipedia.org/wiki/Proton_decay
        
           | hinkley wrote:
           | Neutron decay is one of those things that I forgot between
           | college physics classes and today and it was sort of
           | surprising to rediscover it.
           | 
           | We also know that electrons eventually decay but it's
           | something like 10^26 years, which is long enough to say that
           | probably not many electrons in the solar system have decayed
           | since the universe was born but the universe is really
           | stupidly big, so it absolute numbers that could still be a
           | lot of dead electrons. Maybe a solar system's worth.
           | 
           | Surprisingly there is no wikipedia page for this. Just rando
           | articles.
        
         | kgwgk wrote:
         | Iron is the most stable atomic nucleus (at least if we don't
         | consider Nickel-62).
        
         | ThrowawayTestr wrote:
         | Heat death is just so depressing.
        
           | burnt-resistor wrote:
           | Maybe we should siphon off hydrogen and helium from the Sun
           | for storage elsewhere in the Solar System to reduce the burn
           | rate to prolong the usable lifetime of its fuel? And build a
           | Dyson sphere. ;D
        
             | hinkley wrote:
             | I've watched enough Doctor Who to know that being the last
             | one alive at the end of time is pretty goddamned lonely.
             | And dark.
             | 
             | You can have all of my poptarts, I'm likely to check out.
        
         | amelius wrote:
         | But will the sequence of events be exactly the same in each
         | loop iteration?
        
       | A_D_E_P_T wrote:
       | It's nonsense.
       | 
       | See this comment on their previous paper:
       | https://arxiv.org/abs/2306.07628
       | 
       | The authors of the comment show that the "gravitational pair-
       | production" rate used in the work in OP comes from truncating the
       | covariant heat-kernel (proper-time) expansion of the one-loop
       | effective action at second order in curvature, an approximation
       | that is valid only in _weak-field_ regions where all curvature
       | invariants satisfy _|R| * 2 [?] 1_ (where  is the Compton
       | wavelength). When that same expression is pushed into the high-
       | curvature interior of a neutron star -- where the inequalities
       | fail by many orders of magnitude -- the series is no longer
       | asymptotic and its early terms generate a spurious imaginary
       | part. Because the paper 's entire mass-loss mechanism and
       | lifetime bound follow from that uncontrolled imaginary term, its
       | conclusions collapse.
       | 
       | Simply put, it doesn't even correspond to known experiments. It's
       | _entirely_ driven by a narrow artefact and has no physical basis.
        
         | PaulHoule wrote:
         | The authors wrote a reply to that comment
         | 
         | https://arxiv.org/pdf/2308.12326
         | 
         | I think about how some relativists think you could see a
         | Hawking Radiation like effect if you're accelerating
         | 
         | https://en.wikipedia.org/wiki/Unruh_effect
         | 
         | although the idealized case of endless acceleration implies a
         | certain kind of horizon
         | 
         | https://en.wikipedia.org/wiki/Rindler_coordinates
         | 
         | maybe the horizon doesn't matter much,.
        
           | A_D_E_P_T wrote:
           | There's _a lot_ wrong with that reply -- it mostly just
           | shifts the goalposts without answering the central objections
           | raised in the comment.
           | 
           | Much of the reply revolves around whether the mixed invariant
           | G=E[?]B appears at leading or higher order in the QED
           | Schwinger result. But the comment's critique used the
           | constant-field Schwinger problem only as a check that the
           | authors' master formula fails against a case with an _exact_
           | answer; the real complaint is that the same failure occurs
           | for curved-spacetime examples where the exact result is known
           | to vanish. Debating G is fine, but you can 't ignore the
           | gravitational case either.
           | 
           | The reply repeatedly says the comment is "outside the realm
           | of applicability" of the formula -- as though that were the
           | comment's fault! But if the formula cannot survive the very
           | checks the authors themselves hold up (Schwinger with B[?]0,
           | Ricci-flat space), the burden is on the authors to (severely)
           | restrict their own claims, not on critics to ignore the
           | failure modes.
        
         | LegionMammal978 wrote:
         | Naively speaking, these predictions seem like they should be
         | very sensitive to all sorts of effects, some better understood
         | than others. It's odd how many commenters here treat headlines
         | like these as settled fact, instead of one team's calculations
         | based on assumptions that may be wildly off.
        
       | lawlessone wrote:
       | i'll have to move that meeting forward.
        
       | jeff_carr wrote:
       | /remindme in 10^60 years
        
       | wwilim wrote:
       | Better get around to painting those Warhammer minis soon
        
         | hinkley wrote:
         | I gotta start working on my reading backlog. Luckily I already
         | returned all my library books.
        
       | tsumnia wrote:
       | Glad to see my Collapsing Universe Theory is starting to happen
        
       | 1970-01-01 wrote:
       | Upgrade to Universe 2.0 before our EOL date of 1078 and receive a
       | free 108 month trial of Universe+ with cosmic karma monitoring
       | and additional features such as dark mode.
        
         | usui wrote:
         | I... I thought we already had dark mode..
        
           | kridsdale1 wrote:
           | No. The CMBR of the current universe gives a nice comforting
           | grey. Upgrade today for VantaBlack cosmos, guaranteed no EM
           | at all!
        
             | marcosdumay wrote:
             | Thermodynamic purists hate this thing!
        
             | eGQjxkKF6fif wrote:
             | _cranks up music to 999999 dB_
        
             | AceJohnny2 wrote:
             | ugh, no zero-point energy? What a regression.
        
         | JRCharney wrote:
         | I wish the universe would give me the option not to restart and
         | apply this update right in the middle of a project! It's not
         | like I was working on something or had my browser tabs the way
         | that I like them.
        
       | speckx wrote:
       | Time to dig into that game backlog on Steam.
        
       | charlieyu1 wrote:
       | It's the first time I see unicode exponent numbers actually get
       | used
        
       | foreigner wrote:
       | My HN reader displays this topic as "Universe expected to decay
       | in 10 years, much sooner than previously thought".
       | 
       | And it's not wrong, that _is_ much sooner than previously
       | thought!
        
         | munificent wrote:
         | I mean, it's already decaying. So it will be decaying in 10
         | years too.
         | 
         | It's really a question of when it will _stop_ decaying.
        
           | Bluestein wrote:
           | There go my vacations! :)
        
           | nkrisc wrote:
           | It used to be decaying. It's still decaying, but it used to,
           | too.
        
             | wpasc wrote:
             | The Universe asked me, "Guess what? I'm decaying"
             | 
             | I said, "Dude, you've gotta give me time to guess"
        
         | isk517 wrote:
         | Considering 10^1100 years was the previously postulated time to
         | decay then, assuming the Netherlands Research School for
         | Astronomy is correct in their 10^78 years calculation, 10 years
         | is still significantly closer to the correct date.
        
         | ianburrell wrote:
         | Firefox displays 10^78 with boxes for superscript. Chrome
         | doesn't have any problem.
        
           | burnt-resistor wrote:
           | It could either be your fonts and/or your particular
           | platform. I've seen this sort of thing before elsewhere, I
           | think on Windows with certain fonts IIRC. I opened it on
           | Firefox 138.0.1 on aarch64 for mac and there weren't any
           | artifacts.
        
             | anticensor wrote:
             | Windows has limited font substitution support, that's
             | probably why.
        
           | deepsun wrote:
           | I'm on Firefox -- no problems. Both on Android and Linux.
        
       | graypegg wrote:
       | Damn... got to adjust the roadmap. Universe heat death milestone
       | just got moved up.
        
       | seydor wrote:
       | Bad news for my proton decay stocks
        
       | feverzsj wrote:
       | That's really bad news for immortals.
        
         | hinkley wrote:
         | Better make friends with the creation immortals so you get
         | invited to their parties.
        
       | cozzyd wrote:
       | good news, we'll never need more than a 512 bit time_t
        
       | divbzero wrote:
       | Relative to that time scale we are still, at ~1010 years, in the
       | opening moments of the universe.
        
         | hinkley wrote:
         | If an age of the universe passed for every year the universe
         | has already existed, we'd still have some time left at the end.
        
       | unzadunza wrote:
       | According to The End of Everything
       | (https://www.goodreads.com/book/show/52767659-the-end-of-ever...)
       | decay is only one of the ways it all ends. Unfortunately most
       | (all?) the other ways happen way earlier.
        
       | fuzzer371 wrote:
       | So... Who cares. No one is going to be around even 10^3 years
       | from now. It doesn't help anyone to know, and there's nothing we
       | can do about it.
        
         | the__alchemist wrote:
         | I am suspicious this attitude is responsible for much personal
         | and environmental destruction. I wonder how we can remove it
         | from humanity; it is one of the most dangerous pervasive
         | mindsets for our, and the biosphere's survival.
        
       | JesseTG wrote:
       | If anyone here happens to be immortal, how will you plan around
       | this?
        
       | nottorp wrote:
       | In the long run we're all dead aren't we?
        
         | vasco wrote:
         | And taxes
        
           | nottorp wrote:
           | I believe most jurisdictions stop taxing you when you're
           | dead.
        
         | thebruce87m wrote:
         | You were dead before. On average you've been dead the whole
         | time.
        
       | deadbabe wrote:
       | When we're dead, I know we don't feel anything, but when the
       | universe also becomes dead I wonder if we'll not feel anything to
       | a degree that we didn't even know possible, a death beyond death,
       | if that makes sense. It's like not only are we dead and gone, but
       | our entire life is gone so thoroughly that it's like it never
       | even happened, and if it never even happened, what the hell is
       | this moment we experience now? Just a passing illusion as a
       | universe explodes?
        
       | Workaccount2 wrote:
       | That is about within a factor of 1000 of the number of atoms in
       | the universe. So divide the universe into 1000 compartments of
       | equal atom count, and there is about 1 year left for each atom in
       | there.
       | 
       | To put this in perspective, a drop of water is about 1 trillion
       | groups of 100 billion atoms (or 100 sextillion atoms).
       | 
       | So, we got some time left.
        
       | fallingknife wrote:
       | I was thinking that since apparently Hawking radiation applies to
       | all objects (I thought it was just black holes), maybe it would
       | be interesting to try to actually observe it on the moon. But
       | then I ran the numbers and, if the authors are correct, the moon
       | is losing about 1 electron mass to Hawking radiation every 10^37
       | years!
        
       | BlandDuck wrote:
       | "Estimate of the remaining time before universe decays expected
       | to be revised 10^76 times before its finally over"
       | 
       | (conservatively assuming the estimate will be revised about once
       | every hundred years as we learn more).
        
       | jpease wrote:
       | Accepting table reservations now, you won't want to miss this.
        
         | hinkley wrote:
         | Sorry I'm busy that day. Can we schedule for the following...
         | oh. How about the previous Tuesday?
        
       | Vasniktel wrote:
       | OMG, the economy
        
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