Universe expected to decay in 10⁷⁸ years, much sooner than previously thought
61 comments
·May 12, 2025terabytest
AnonC
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.
diego898
Very strongly suggest you check out Isaac Asimov’s “The Last Question”
felipeerias
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.
mykowebhn
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
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
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.
bbarnett
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?!
saberience
See The Last Question, by Isaac Asimov:
blueflow
It is written
The researchers calculated that the process of Hawking radiation theoretically also applies to other objects with a gravitational field
jfengel
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
> 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.
mr_toad
No, all objects with non-zero temperature radiate heat. Stars, white dwarfs, black holes, even the universe itself.
blueflow
I said
inert rock at background temperature
dist-epoch
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.
ourmandave
Oh great, right after I sell my soul for immortality, then they announce this.
Thanks a lot guys.
nindalf
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
Assuming life to be entirely physical, of course.
anilakar
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
Don't worry. You still get to experience things when your fermionic matter is converted into bosons. Have fun.
Joker_vD
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.
fsiefken
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.
wewewedxfgdf
Despite it being quite a way out it's still a little sad to think the end is coming.
rswail
"quite a way out"... is doing a lot of work in that sentence.
maaaaattttt
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?
rswail
People will be gathering at the Restaurant At The End Of the Universe with Douglas Adams as the host.
dvh
> 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
Extropy_
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."
Etheryte
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
get your affairs in order.
coolcase
Another 10^3 would be good for humanity
Ekaros
One more argument not to do anything about climate change. After all universe is going decay shortly...
MOARDONGZPLZ
I hope they’re working on finding a way to massively decrease the net entropy in the universe after this.
andreareina
Unfortunately there is as yet insufficient data for a meaningful answer
watt
Crack on with it and don't keep us in the dark!
coolcase
The way to do that is to do the most unlikely things
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?