When the last star dies

Submitted by trunktunk t3_yhpofz in space

When every star dies and there are only black holes left, could it be possible that every black hole left joins each other? If that's possible what happens when a black hole dies? Does that one "giant" black hole collapses on itself and dies and there is just nothing, could there be another 'Big Bang' if that's a possibility? something so big that could only happen from a massive black hole that another universe of life starts again? BTW I'm only a music performance major, I never thought myself smart enough to be good enough at astronomy and physics so this is just a "shower question"

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BlueTommyD t1_iuf2hqu wrote

When the last star dies, we will eventually get a "last" black hole, but not because they will merge.

Black holes give off radiation which actually reduces their mass over time called Hawking radiation.

So, eons after the last star dies, the last black hole will fade from existence.

What happens after that, is really anyones guess. But we have zero evidence that points to anything other than stable equilibrium for eternity (not that time would really have any meaning at that point.)

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tvalvi001 t1_iuf5nx0 wrote

That’s one heck of thoughts there too. Mind boggling stuff

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mschurma t1_iuf85ez wrote

Layman question and it’s been awhile since physics class lol, what happens to the mass let off by all the Hawking radiation at that point? Is there any mechanism that converts radiation back to mass? I get E=mc2, that energy would still exist right? Is there any mechanism that could start turning that back into matter, and given time/gravity, start forming stars again?

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3Dbpb t1_iugetpw wrote

Not a theoretical physicist but I believe the theorized mechanism involves virtual particles. They are pairs of particles that pop up everywhere in particle antiparticle pairs. Normally they recombine nearly instantly but at the event horizon it may be that one of the paired particles falls into the black hole and the other escapes.

The issue with reforming stars is the universe is expanding at an accelerating rate. Which means while there will still be particles they will be isolated and too far away to combine into stars.

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carbonqubit t1_iuggct6 wrote

Virtual particles are a bit of a misnomer, as they're actually mathematical constructs that arise from perturbation theory and used to resolve certain complexities in quantum mechanics. Said another way, theoreticians use them to help better estimate particle interactions like those between say two electrons.

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BlueTommyD t1_iufbhhb wrote

Right. There is no ELI5 for Hawking Radiation - it's too weird. And I am not a Quantum Physicist.

Hawking Radiation is a particular kind of Thermal Radiation that "leaks" from the tiny distance around the Event Horizon of a Black Hole. The radiation never actuallty comes from "inside" the Event Horison, yet it steals energy from the Black Hole - and in a Black Hole, mass and energy are essentially the same thing.

Hawking Radiation itself isn't perfect - and could to the Black Hole Information Paradox - where Black Holes *are* actually deleting information from the universe - although this is up for debate and there are theories which correct for this.

As far as I am aware, you can't turn the energy emitted back in to mass - without just throwing it in to another black hole.

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Other_Evidence8818 t1_iuglcnz wrote

Fusion and fission are mechanisms for turning energy into matter. But after heat death, on average these processes won't be occurring as there are no gradients.

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Ok-Expression7533 t1_iuhbt2i wrote

This also goes into the issue of the nature of infinity time. Like, before all of spacetime happened, time was irrelevant. Equilibrium should have just been forever and ever. Whether it was created or accidental or whatever. It's such a ridiculous, non-intuituve landscape to navigate. We know that spacetime as we know it has had a non-zero chance of occurring, because it is occurring. So rationally it is not unreal to assume that it could be happening infinity times in the past and infinity times in the future and infinity times concurrently. The nature of reality is fucking insane.

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shydude92 t1_iuhj3kd wrote

I was thinking about this too. There's actually something called the Poincare recurrence time, which is the approximate amount of time it would take for a region of spacetime the size of our observable universe to just pop into existence based solely on quantum effects. Unsurprisingly, it's extremely long, involving a power tower of about 5 tens, with a 1.1 at the end. At this length, units don't matter, because whether you use Planck times or years, the difference doesn't really affect the exponent.

Of course, that's nothing compared to infinity, literally; however, there are several problems. First, it's not known if time would still exist in any meaningful sense at this point, since all that would exist would be distended and scattered particles. Owing to the rapid expansion of space, these particles would eventually get so far apart that no particle would be in any other's observable universe and thus no causal contact could be made, and hence you might argue that no time could exist because no longer would there be any way of measuring or observing it. Also, the Poincare recurrence would be much shorter for a region of spacetime much smaller, like the solar system, which would be all we need to exist, hence the question of why our own universe is so large if this presumably wouldn't be the first cycle. One possibility is that there are no cycles, because the PRT does not exist; or, potentially we may live in a multiverse with new regions emerging all the time so the bulk of matter ends up existing in "young" universes, while older ones that have achieved maximum entropy or heat death occasionally experience small spontaneous entropy decreases that amount to only tiny fragments of all matter present.

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DonOctavioDelFlores t1_iufew0l wrote

And what about proton decay?

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sasquatchical t1_iufhrls wrote

Because no real particles with a positive energy can escape the curvature of the black hole, we wouldn’t necessarily be able to detect this occurring from the event horizon. The only “easy” way to explain black hole evaporation is through Hawking radiation.

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Zer0Summoner t1_iuf27o1 wrote

You're describing a theory called the "Big Crunch." It isn't the currently favored theory, but it is one of the theories out there.

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trunktunk OP t1_iuf3jhx wrote

Oh really! That’s cool I’ll look more into that theory thank you!

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Varlex t1_iuf2ozm wrote

There are 2 possible options.

a. The expansion of the universe reverse at a certain point

B. It will expand for ever

A. In this case, the universe fall back into a new singularity.

B. The universe will be more and more cold and the distances between objects increase and the black holes and dust stay for itself. (So galaxies, maybe cold still exist as more and more single objects, because the gravity can't hold more objects together)

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Varlex t1_iuf4sy7 wrote

In addition to B)

You can still have planet, dead suns and other stellar objects in a galaxy, as long it has a stable orbit.

But like other mentioned, hawking radiation is a topic. When background radiation will be smaller then hawking radiation from a big black holes, it loses energy = mass. Because it loses mass, the orbit from all objects around will increase. So in a long long long future it could be, that galaxies disband and only some single solar systems with dead suns exists...

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trunktunk OP t1_iuf46a6 wrote

For the first point when it reverses, do you mean like it’ll un do everything that happened?

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tvalvi001 t1_iuf5ir9 wrote

Rather than an undoing, it’ll be more of a crunching together of all in the universe into one big piled up ball of everything

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trunktunk OP t1_iuf6k14 wrote

Woah, that’s crazy to think about. So it’d like get smaller?

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tvalvi001 t1_iuf6xv1 wrote

Theorists have it that it’ll crunch down to a single point in the same way the Big Bang occurred, or something like it. This used to be a very popular theory but I guess over the years many astrophysicists have gone on to ponder other possibilities, but I’m not intelligent enough to understand them lol

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Varlex t1_iuf8myr wrote

It depends, and currently we can't measure it with enough accuracy.

Most of the scientists thinks a big chill will happen (the universe will be more could from time to time).

I read more, it could be, when the temperature is more next to 0K also atoms will disintegrate into photons and electrons.

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tvalvi001 t1_iufa6lk wrote

Just for clarity, when you wrote 0K you meant 0 kelvin?

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Varlex t1_iufc523 wrote

Yes.

And you know the 2. Law of thermodynamics. So atoms will lose their energy and disintegrate after some times.

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tvalvi001 t1_iufd4j9 wrote

That makes the whole “Big Chill” a lot more clear now. It makes sense that it’d be more plausible too

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TheDinoIsland t1_iuffie4 wrote

The big bang/crunch seems to make the most sense. It kinda provides an answer to why we exist. This could be our trillionth life and we would never know it.

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Varlex t1_iuf7f5i wrote

No, the distance between objects in stellar will be smaller. The expansion or the opposite doesn't matters a lot for us.

Currently the room between all objects increase, also between sun and earth. But the gravity can easily hold it together.

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Varlex t1_iuf5byv wrote

From what i know, this will not happen.

Time is still a vector which is ongoing, where the room will be smaller from time to time.

Then gravity force objects into each others and the energy density increase, so the universe will heat up.

At a certain point it's so hot, matter don't exist and it falls into its subparticels.

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Varlex t1_iuf5tmp wrote

>Time is still a vector which is ongoing, where the room will be smaller from time to time.

In addition to this. The universe could be still infinite, but it's smaller then before ;)

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whativebeenhiding t1_iuffjye wrote

I just read a book that talked about seven ways the universe could end. The End of Everything: Astophisically Speaking

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HermeticallyInterred t1_iufa2t8 wrote

This does an awesome job at answering your question and addressing some of the topics brought up by others.

Timelapse of the Future: https://youtu.be/uD4izuDMUQA

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ExtonGuy t1_iuffpkm wrote

When the last star dies, when the last black hole evaporates, the universe will be left with just photons, electrons, and neutrinos (and their antiparticles). These will never meet, or if in very very rare circumstances they do meet, no new mass/energy conversion will happen.

There is some wild speculation that there might be another Big Bang of some sort, born out of quantum foam … but there is no way to test that idea.

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BritCanuck05 t1_iufftbq wrote

Are atoms immortal or will they eventually break down into their sub atomic particles?

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ski233 t1_iug91w6 wrote

I believe the current theory is they will break down.

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[deleted] t1_iuf52j5 wrote

[deleted]

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trunktunk OP t1_iuf6hkt wrote

Oh I thought it was natural that when stars die after the white dwarf stage they turn to black holes

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Ill_Sky4073 t1_iugxw9h wrote

When a white dwarf eventually burns out, it will turn into a black dwarf- basically a cinder in space. But the universe is too young for this to have happened yet. Black holes are the result of massive stars collapsing under the pressure of their own gravity once they can no longer resist it through the power of their fusion reactions.

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will4111 t1_iufazyq wrote

Don’t forget quasars. Black holes shoot all the stuff back out into space.

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Varlex t1_iufd5gk wrote

You mixed up things.

Quasars don't blow stuff from inside the black hole, it's still part of matter from outside of the black holes.

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will4111 t1_iufe06z wrote

Yes, and I’m not sure it even has a name. But black holes do have massive jets of energy they burp out. Not sure about the inside or outside part.

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Varlex t1_iufen53 wrote

It's matter outside from the accretion disk, so the incoming mass.

I don't know the fully theory behind it, but it heat ups so massive, that it's going to the poles of the black hole and send out as a jet.

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trunktunk OP t1_iufbbe0 wrote

Seriously??? I thought black holes just sucked stuff up and it was gone from existence

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will4111 t1_iufc1al wrote

Great series on the science channel. How the the universe works explains stuff like this and seen now even tiktok videos that people make of how gravity works from examples of the show from like 2015.. I’m no scientist I’ll let the professionals explain it, great show.

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FTP-Allofthem t1_iufcmqx wrote

Watch “Timelapse of the future” on youtube. Thank me later…

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deasnutz t1_iufihe7 wrote

We can only guess what will happen trillions of years in the future. But with the data we have now it seems the universe is perpetually expanding in a flat shape, pushing most objects away from each other. That said we don’t understand dark energy, only see some evidence for it.

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Cryptic-Raccoon t1_iufqw7u wrote

When there are only black holes left, the distances between them caused by expansion will be so great, they will likely never merge or see each other

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Updooting_on_New t1_iufkf7v wrote

i like to think that eventually black holes may implode due to the ringularity becoming unstable, releasing their material to space, giving birth to new stars and there we go again

i really hope something like this happens

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MD_Tarnished t1_iugm6a4 wrote

Well when the last star dies, we all diededed by then pretty sure

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smaaskakk_tronder t1_iui7blz wrote

Lots of black holes, blocked from interacting in any way because spacetime expands too fast and too far, excruciatingly slowly losing mass one tiny particle at a time until (10^100)^100 years later they all fizz out, leaving solitary photons just cruising along on their own, never to meet any other photon again. At this point, mass, velocity, distance, volume etc all lose meaning.

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NotAHamsterAtAll t1_iuhcmql wrote

You can expect the correct answer to this, when we have figured out everything about the universe.

We have about 2% figured out.

So any answer you'll get is going to be wrong.

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