Universe expected to decay in 10⁷⁸ years, much sooner than previously thought

One of my favorite Wikipedia pages<p><a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Timeline_of_the_far_future" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Timeline_of_the_far_future</a>

My HN reader displays this topic as &quot;Universe expected to decay in 10 years, much sooner than previously thought&quot;.<p>And it&#x27;s not wrong, that _is_ much sooner than previously thought!

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.

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 :)

Better get around to painting those Warhammer minis soon

It is written<p><pre><code> The researchers calculated that the process of Hawking radiation theoretically also applies to other objects with a gravitational field </code></pre> but: doesn&#x27;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 -&gt; stable ones) and end up as inert rock (stable nuclides) at background temperature.

As someone who doesn’t know much about this, I&#x27;m curious:<p>If humanity survived far into the future, could we plausibly develop ways to slow or even halt the decay of the universe? Or is this an immutable characteristic of our universe, meaning humanity will inevitably fizzle out along with the universe?

I wonder how you decide to measure things in years on this scale. I mean, in about 10^10 years, the whole concept of a &#x27;year&#x27; will stop to exist. What will you do then?<p>I would expect something like &#x27;tera-seconds&#x27;, 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.

Bad news for Boltzmann brains

So Hawking radiation moves the estimate from the previous 10^1100 to 10^78 years. That&#x27;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&#x27;s still some way to go.

Despite it being quite a way out it&#x27;s still a little sad to think the end is coming.

Bad news for my proton decay stocks

&gt; In 1975, physicist Stephen Hawking postulated that contrary to the theory of relativity, particles and radiation could escape from a black hole. At the edge of a black hole, two temporary particles can form, and before they merge, one particle is sucked into the black hole and the other particle escapes.<p>Hasn&#x27;t this explanation been discredited for a while?<p><a href="https:&#x2F;&#x2F;bigthink.com&#x2F;starts-with-a-bang&#x2F;hawking-radiation-black-hole-evaporation&#x2F;" rel="nofollow">https:&#x2F;&#x2F;bigthink.com&#x2F;starts-with-a-bang&#x2F;hawking-radiation-bl...</a><p>&gt; 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.<p><a href="https:&#x2F;&#x2F;bigthink.com&#x2F;starts-with-a-bang&#x2F;hawking-radiation-really-work&#x2F;" rel="nofollow">https:&#x2F;&#x2F;bigthink.com&#x2F;starts-with-a-bang&#x2F;hawking-radiation-re...</a>

It&#x27;s nonsense.<p>See this comment on their previous paper: <a href="https:&#x2F;&#x2F;arxiv.org&#x2F;abs&#x2F;2306.07628" rel="nofollow">https:&#x2F;&#x2F;arxiv.org&#x2F;abs&#x2F;2306.07628</a><p>The authors of the comment show that the &quot;gravitational pair-production&quot; 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 <i>weak-field</i> regions where all curvature invariants satisfy <i>|R| · ℓ² ≪ 1</i> (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&#x27;s entire mass-loss mechanism and lifetime bound follow from that uncontrolled imaginary term, its conclusions collapse.<p>Simply put, it doesn&#x27;t even correspond to known experiments. It&#x27;s <i>entirely</i> driven by a narrow artefact and has no physical basis.

Aw fuck!!<p>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&#x27;t want to deadhead so hopefully there&#x27;s plenty more interesting things to do in the tail end. Hahaha :)

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?

According to The End of Everything (<a href="https:&#x2F;&#x2F;www.goodreads.com&#x2F;book&#x2F;show&#x2F;52767659-the-end-of-everything" rel="nofollow">https:&#x2F;&#x2F;www.goodreads.com&#x2F;book&#x2F;show&#x2F;52767659-the-end-of-ever...</a>) decay is only one of the ways it all ends. Unfortunately most (all?) the other ways happen way earlier.

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.<p>To put this in perspective, a drop of water is about 1 trillion groups of 100 billion atoms (or 100 sextillion atoms).<p>So, we got some time left.

good news, we&#x27;ll never need more than a 512 bit time_t

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

It&#x27;s the first time I see unicode exponent numbers actually get used

Accepting table reservations now, you won’t want to miss this.

My shower is theory is that there are infinite universes getting created all the time and we can never know about it because we&#x27;re restricted in this universe. I love having these talks with my daughter.

I always assumed that an event horizon was a necessary condition for hawking radiation (or the Unruh effect, for inertial frames). Interesting that this apparently isn&#x27;t the case, and the authors rather predict all objects with mass to have this property.

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!

Evaporation isn’t as bad as false vacuum decay. I thought the news would be about that. Fast vacuum decay would be much worse, as civilization can withstand matter loss but not the ultimate false vacuum decay

&gt; Previous studies, which did not take this effect into account, put the lifetime of white dwarfs at 10^1100 years<p>That&#x27;s some kind of typo no? I&#x27;ve only heard previous estimates for white dwarf to be trillions of years, that is significantly shorter that 10^1100<p>Edit: never mind, by lifetime that me proton decay, not how long they shine light

Damn. That ruins my retirement plans

&quot;Estimate of the remaining time before universe decays expected to be revised 10^76 times before its finally over&quot;<p>(conservatively assuming the estimate will be revised about once every hundred years as we learn more).

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&#x27;t time be almost still once, let&#x27;s say, year 10⁷⁷ is reached?

This is the original paper: <a href="https:&#x2F;&#x2F;arxiv.org&#x2F;abs&#x2F;2410.14734" rel="nofollow">https:&#x2F;&#x2F;arxiv.org&#x2F;abs&#x2F;2410.14734</a><p>They say their findings set &quot;a general upper limit for the lifetime of matter in the universe.&quot;

If anyone here happens to be immortal, how will you plan around this?

Other gravitational bodies radiating via hawking radiation is a bold claim. Has this work been validated? Challenged? Confirmed?

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

There’s no way that we happen to exist in just the first 10^78 years of eternity.

That&#x27;s really bad news for immortals.

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

TLDR: Hawking radiation can cause things besides black holes to evaporate.<p><pre><code> Man and moon: 10^90 years</code></pre> 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&#x27;s 10^90 years. Of course, the researchers subtly note, there are other processes that may cause humans and the moon to disappear faster than calculated.

Relative to that time scale we are still, at ~10¹⁰ years, in the opening moments of the universe.

Bad news for Bryan Johnson, he will have to adjust some of his long term plans

Did Broadcom acquire this Universe?

Darn, I&#x27;ll have to cancel my party plans for that weekend.

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

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

Good. Maybe now they can prove Hawking radiation in something that isn&#x27;t a bath tub. Or an oven.

Damn... got to adjust the roadmap. Universe heat death milestone just got moved up.

But I just bought a house in the universe!

&gt;Because the researchers were at it anyway, they also calculated how long it takes for the moon and a <i>human</i> to evaporate via Hawking-like radiation. That&#x27;s 10^90 years.<p>Well I can predict the next trend, launching very rich people&#x27;s body into space so it will last 10^90 years :)

Damn, I had planned to go shopping on that day!

Glad to see my Collapsing Universe Theory is starting to happen

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

In the long run we&#x27;re all dead aren&#x27;t we?

Could be just one accidental Ctrl+C away.

I better update my will.

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

I don&#x27;t know why 10^78 unsettles me more than 10^1100 does.

OMG, the economy

This is as removed from any observation and predictive utility as counting angels on the head of a pin.

i&#x27;ll have to move that meeting forward.

Oh no, all my plans for the 10^100 year celebration party!

so many years - and how many miles?

so i wonder what comes after?

To me that still sounds like forever.

&#x2F;remindme in 10^60 years

Now I feel like an idiot for paying off my house

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

the term &quot;sooner&quot; in this case is, you know, relative

Time to dig into that game backlog on Steam.

AI is going to take over anyways

So... Who cares. No one is going to be around even 10^3 years from now. It doesn&#x27;t help anyone to know, and there&#x27;s nothing we can do about it.

Ok, well, surviving beyond 1 billion years and various extinction level events, asteroids, comets, nuclear wars, are are the first priority, we&#x27;ll worry about this later.<p>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.<p>If we survive, &#x27;we&#x27; most probably don&#x27;t exist by that time in any recognisable shape or form.