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
You'd like this book: https://mitpress.mit.edu/9780262547222/an-infinity-of-worlds...
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.
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.
If there are no physical laws, there’s nothing to stop that happening.
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 :) )
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putting arcane physics and cosmology within reach of (still decently-educated) normal people, but it is very outdated in a lot of respects.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.
The researchers calculated that the process of Hawking radiation theoretically also applies to other objects with a gravitational field
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.
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.
inert rock at background temperature
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?
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?
Instead, its response—"INSUFFICIENT DATA FOR MEANINGFUL ANSWER"—is a model of intellectual honesty.
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?!
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.
The World at the End of Time by Frederick Pohl.
https://en.wikipedia.org/wiki/Iron_star#Compact_iron_star_fo...
...although I'm not sure I've ever seen the expected temperature of iron stars. 1 milliKelvin?
We don't need to worry, it is highly unlikely that humanity as we recognize it will exist.
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.
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?
“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.
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.
>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.
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.
That's... awe inspiring.
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/interpre...
[2]: https://en.wikipedia.org/wiki/Timeline_of_the_far_future
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_univers...
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!
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.
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.
They say their findings set "a general upper limit for the lifetime of matter in the universe."
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.
The idealized Star Trek society of production automation and exploratory self fulfillment might only be possible, and sustainable, if we are a billion people.
That is still plenty enough people to continue our ever accelerating and vast exploration of culture, science and space.
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.
Well I can predict the next trend, launching very rich people's body into space so it will last 10^90 years :)
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.
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?
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.
The "no more strength, no way out" part kills me every time I watch it.
Looks like a new test case scenario for libraries that handle time/date.
Could you imagine if anyone was stupid enough to think the right place to handle such a thing was the internal counter of seconds rather than the datetime library though? Ha! That’d be ridiculous right! Imagine all the bugs if someone put something that’s only relevant to local timezone time printing there! It’d cause so many unexpected bugs!
Just consider the weird but valid scenario in relativity where A can occur before B, B before C, and C before A. I'm not sure how you would wrangle something like that in a data format.
I don’t think we have the ability to meaningfully predict such scales.
I'm all for thinking of the children, but planning at that range is probably impossible.
This of course requires the decay of protons.
if time passes and there's no observable difference, did it pass? I guess it makes no meaningful difference, but it's not really answering the underlying question of if some variable is advancing or not.
If nobody logs in to a multiplayer game, does the game world still exist?
Sure there are files sitting on a server somewhere waiting to be read when the first user logs in, there may even be a physics engine polling abstract data structures for updates, but the game world doesn't render without players present with their computers bringing all this data into a coherent structure.
Also, for an extra existential kick, realize that it renders /independently/ in the GPU/CPU/RAM of each player's computer.
heat death just implies no work can be done. time still flows
First, in many local processes entropy moves from high to low (e.g. life). Nobody says that time is moving backwards for living things. It only increases if you consider the system it is embedded in as well. So this idea that entropy is time is something that only applies to the entire universe?
It's true that we don't see eggs unbreaking, or broken coffee cups flying off the floor and reassembling. This increase in entropy seems to give an "arrow" of time, but to my mind this view (ironically) confuses cause with effect.
If you have any causal system (cause preceding effects) then you will always see this type of entropic increase, by simple statistics. There are just many, many more ways for things to be scrambled and high entropy than ordered and low entropy.
So yes, entropy does tend to increase over time, but that's an effect of being in a causal system, not the system itself. At least, that's my view.
Perfectly true that entropy gets us in the end as we age, as the system breaks down and cannot sustain itself any longer. Although if we could fix those systems, there's no reason in principle we couldn't halt aging entirely.
I am slightly blending the concept of entropy and complexity. But "ordered complexity" is how I imagine it.
It works a bit like air conditioning: yeah, you can make one room cold, but only by making more heat outside the room. The overall temperature of the system increases.
Partly, but mostly because there would be no lunch, so there would be no illusion of lunch-time any more.
This is required to make Penrose's end state Conformal i.e. scale invariant, so that it can arbitrarily Cycle to a small scale to make a new Bing Bang Cosmology (CCC).
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!
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.
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.
You might be thinking of protons.
It's ridiculous to cite an unnamed paper while being unable to procure a single source on the internet and then proclaim it's equally likely that they might or might not decay. With everything we know about physics there is absolutely no way imaginable that they might decay.
You can have all of my poptarts, I'm likely to check out.
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.
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,.
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.
Offer not available for Stuart Semple.
(Incidentally, if you don't know about this wonderful feud, it's worth reading up on it. If you know a little bit about it but have not kept up with the news, it may give a flavor of the whole to know that Stuart Semple's latest troll (that I am aware of) was changing his name to Anish Kapoor.)
And it's not wrong, that _is_ much sooner than previously thought!
It's really a question of when it will stop decaying.
I said, "Dude, you've gotta give me time to guess"
What reader do you use? I've only ever used vanilla HN.
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.
This sounds tedious, but it might help to realize you can just gather all the atoms together first, and then count only every 1000th one.
(conservatively assuming the estimate will be revised about once every hundred years as we learn more).
Man and moon: 10^90 yearsHasn't this explanation been discredited for a while?
https://bigthink.com/starts-with-a-bang/hawking-radiation-bl...
> Black holes are not decaying because there’s an infalling virtual particle carrying negative energy; that’s another fantasy devised by Hawking to “save” his insufficient analogy. Instead, black holes are decaying, and losing mass over time, because the energy emitted by this Hawking radiation is slowly reducing the curvature of space in that region. Once enough time passes, and that duration ranges from approximately 10^68 to 10^103 years for black holes of realistic masses, these black holes will have evaporated entirely.
https://bigthink.com/starts-with-a-bang/hawking-radiation-re...
Who knows? Maybe when and if that happens, civilizations will be advanced enough to try to reverse this: manipulating the local Higgs field, pocket universes, and counter-decay waves
I would expect something like 'tera-seconds', or something related to a cosmological constant but at cosmological scale, like the time to decay hydrogen or number of caesium vibrations for example, but then scaled at AU scale. A value not related to time or space.
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 all 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. Hahaha :)
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