JohnMakin an hour ago

Bad news for Boltzmann brains

  • matheusd an hour ago

    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 43 minutes ago

      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.

    • x1000 31 minutes ago

      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.

foobarkey 28 minutes ago

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 :)

  • layer8 8 minutes ago

    The evidence about the expansion of the universe would seem to contradict that theory.

  • HideousKojima 10 minutes ago

    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!

lawlessone 11 minutes ago

Damn, i'll have to move that meeting forward.

jeff_carr 8 minutes ago

/remindme in 10^60 years

blueflow 6 hours ago

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.
  • jfengel 5 hours ago

    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 5 hours ago

      > 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

  • pixl97 an hour ago

    >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?

  • mr_toad 5 hours ago

    No, all objects with non-zero temperature radiate heat. Stars, white dwarfs, black holes, even the universe itself.

    • blueflow 5 hours ago

      I said

        inert rock at background temperature
      
      so radiated and absorbed heat should already be accounted for, right?
  • dist-epoch 6 hours ago

    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.

dan_can_code an hour ago

Damn. That ruins my retirement plans

  • bdangubic an hour ago

    just in time for your 401k to recover :)

terabytest 6 hours ago

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?

  • AnonC 5 hours ago

    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 an hour ago

      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 an hour ago

        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 25 minutes ago

        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.

    • isoprophlex an hour ago

      Is that right? Only 5 billion years until noone sees the background radiation and other galaxies?!

      That's... awe inspiring.

      • ChrisClark an hour ago

        That seems relatively soon! I know it's a huge number, but on universal scales, that's crazy

    • glenstein an hour ago

      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 an hour ago

      This is a good reason not to throw away your old textbooks.

  • GistNoesis 17 minutes ago

    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.

  • bee_rider an hour ago

    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!

  • felipeerias 5 hours ago

    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 an hour ago

      The origami of petal unfolding implies the rose blooms forever says all bugkind dwelling on the bud.

  • saberience 5 hours ago

    See The Last Question, by Isaac Asimov:

    https://users.ece.cmu.edu/~gamvrosi/thelastq.html

    • Vox_Leone 42 minutes ago

      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 5 hours ago

    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 5 hours ago

      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.

      • rswail 5 hours ago

        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 4 hours ago

          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.

      • bbarnett 5 hours ago

        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 an hour ago

          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 4 minutes ago

            They'll exist because of Wan-To.

            The World at the End of Time by Frederick Pohl.

  • krapp 5 hours ago

    The Second Law of Thermodynamics is an immutable characteristic of our universe. Entropy in a closed system (like the universe) is irreversible.

    • exe34 5 hours ago

      It was set to zero once, so somebody somewhere/somewhen figured it out before.

      • WhatsName 4 hours ago

        Or rather we are a fork/thread somewhere is spacetime.

A_D_E_P_T 17 minutes ago

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| · ℓ² ≪ 1 (where ℓ 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.

IamLoading 32 minutes ago

If humans end up existing at 10^77 years. You would hope and imagine that they would be prepared for the decay?

  • recursive 10 minutes ago

    Well, that's only 10% of the way there, so they'd still have most of the time left.

wewewedxfgdf 6 hours ago

Despite it being quite a way out it's still a little sad to think the end is coming.

  • rswail 5 hours ago

    "quite a way out"... is doing a lot of work in that sentence.

belter 37 minutes ago

Did Broadcom acquire this Universe?

Etheryte 6 hours ago

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 6 hours ago

    get your affairs in order.

  • coolcase 5 hours ago

    Another 10^3 would be good for humanity

rswail 4 hours ago

People will be gathering at the Restaurant At The End Of the Universe with Douglas Adams as the host.

dvh 6 hours ago

> 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

maaaaattttt 5 hours ago

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 an hour ago

    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.

mediumsmart an hour ago

so many years - and how many miles?

fsiefken 5 hours ago

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.

  • rTX5CMRXIfFG 43 minutes ago

    What values do you think we should optimize for?

  • NoMoreNicksLeft an hour ago

    I suspect we have more immediate problems than "can we survive the next n billion years".

    • 2OEH8eoCRo0 an hour ago

      There have already been close calls with nukes. No way in hell we last another hundred.

Ekaros 5 hours ago

One more argument not to do anything about climate change. After all universe is going decay shortly...

MOARDONGZPLZ 6 hours ago

I hope they’re working on finding a way to massively decrease the net entropy in the universe after this.

  • andreareina 6 hours ago

    Unfortunately there is as yet insufficient data for a meaningful answer

    • watt 6 hours ago

      Crack on with it and don't keep us in the dark!

  • coolcase 5 hours ago

    The way to do that is to do the most unlikely things

tobias_irmer 6 hours ago

To me that still sounds like forever.

jmclnx an hour ago

>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 an hour ago

    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.

chasing an hour ago

Probably on a Thursday. I never could get the hang of Thursdays.

stavros 5 hours ago

Oh no! What are we going to do about this?

octocop an hour ago

the term "sooner" in this case is, you know, relative

andrewstuart 5 hours ago

How can the universe come from an infinite point and have no Centre.

  • laxd 36 minutes ago

    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.

  • acuozzo 42 minutes ago

    The center is everywhere.

Aetheridon 6 hours ago

so i wonder what comes after?

  • Lerc 5 hours ago

    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 5 hours ago

      There is a theory out there that once heat death is done distance is meaningless, therefore zero, therefore big bang again.

      • laxd 27 minutes ago

        Conformal cyclic cosmology, by Roger Penrose

      • Lerc 5 hours ago

        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.

    • mr_toad 5 hours ago

      > 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 5 hours ago

    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 :) )

  • willis936 6 hours ago

    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

Ygg2 5 hours ago

Good. Maybe now they can prove Hawking radiation in something that isn't a bath tub. Or an oven.

vijaybritto 6 hours ago

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.

thom 5 hours ago

Ah, just time for another bath. Pass me the sponge somebody, will you?

ourmandave 6 hours ago

[flagged]

  • nindalf 5 hours ago

    I wonder, is immortality a boon or a curse? So many depictions of immortality show the person suffering. At least there's an upper bound on the suffering though, only 10^78 years.

    • lblume 5 hours ago

      Assuming life to be entirely physical, of course.

  • anilakar 5 hours ago

    I had calculated I could finally afford to retire after some 10^228 years. Looks like I can safely nuke my pension savings now.

  • ImHereToVote 5 hours ago

    Don't worry. You still get to experience things when your fermionic matter is converted into bosons. Have fun.

  • Joker_vD 6 hours ago

    Huh. When I've tried to sell my soul, I was scolded that trying to sell something you don't own in the first place is bad style. Oh, and they've also changed my last name to "Asshole" in all of my papers, such pettiness :/

    I think you've gotten away pretty well.

m1117 6 hours ago

AI is going to take over anyways

  • coolcase 5 hours ago

    It'll be 42'd like everything else

keepamovin 6 hours ago

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.