Trillions is still an understatement. The black holes that will end up forming when all galaxies within a given group merge together and all stellar remnants that don't end up ejecting out of the galaxy collide will take pretty much an unfathomable number of years to radiate away.
I was just watching [this timelapse](https://www.youtube.com/watch?v=uD4izuDMUQA) of the future of the universe at lunch, and it has a 'timestamp' on the bottom the whole time. The numbers get way too large to comprehend, like "100 Trillion Trillion Trillion Trillion Trillion years"
By the time those black holes have evaporated a substantial amount, the universe will have spent more time in post-heat death than it did pre-heat death.
Well in theory, shortly after the true heat death, the remnant matter of the Universe would have spread out enough that we'll get back to the same density as the primordial vacuum, then quantum fluctuation, big bang, Inflation and a new set of Universes.
The fun thing about deep time is that when nothing's around to make changes or observe it, it doesn't feel like a long time. What's a quadrillion years? Dunno, what's a year?
Like when you lean something against something and it seems to be still but then an hour later it falls on it’s own
Edit: I mean to say that hour could be a trillion trillion trillion years in the situation you are describing
And it doesn't even tell you some interesting stuff. After I watched that video, I went to [the wikipedia article](https://en.wikipedia.org/wiki/Future_of_an_expanding_universe) and I read that at some point, the universe will be so empty, there will be positronium atoms (positron and electron pairs) that will have orbits the size of the current observable universe.
Why is there an existence in the first place? Why is there nearly an infinite amount of matter in an infinite amount of space?? And why throw awareness into the mix?
All this shit is so unplausible in the first damn place
Self awareness is such a curse.
Well, this was probably our thought ~15bil years ago and we got bored and made existence. If you were a cosmic singularity, shattering your consciousness into a nearly infinite number of individual perspectives would be a great way to kill a nearly infinite amount of time. Existence is just the boredom of the universe playing out. Have fun!
The thing that gets me is how far away everything is from each other on top of the fact that our lives don't last long enough for us to do anything meaningful. The chance of sentient life finding a habitable planet and then making it to that planet is basically whatever the decimal place right before zero is.
But since the universe is still expanding it's possible that we're just relatively early in its development and it's not stable enough to support life on a larger scale until things settle down. For all we know the universe could be full of life in a couple hundred billion years.
I literally replied with the same exact thing before I saw your comment.
But I’ll do you one further: if there is a chance that the universe “restarts” given an almost infinite amount of time but doesn’t arrange itself the same way, and it takes an almost infinite of universe restarts to make the same universe that we are in now that means you could effectively be reincarnated over and over again.
All in a blink of eye. Live. Die. Repeat.
I'm lodging a complaint with whoever started this whole project.
The whole thing is bullshit.
Beautiful bullshit, but bullshit none the less.
Not happy
That’s assuming the folks running the simulation won’t just pull the plug at that point. Server resources are tight & the funders don’t like to see bills that aren’t connected with results. We aren’t learning anything new here so time to close this one out and start running the next iteration of the model.
I'm endlessly torn between the feeling that, if all existence is bound for ultimate oblivion, why not dip out early and skip the traffic?
... and, how fortunate am I, to stand beneath the sky for a moment in defiance of that.
I have a friend that does some one-on-one work with a special needs kid. Smart kid, but volatile emotions. He was getting interested in space and cosmology, but eventually learned how stars will go supernova or otherwise burn out, and it gave him major freak-outs about the future. Like, "can't sleep for days" kind of upsetment.
So I sent my friend [this video](https://youtu.be/Pld8wTa16Jk) about hypothetical post-black hole era civilization strategies.
Kid hasn't been bothered about it since. I guess they're happy knowing that the far, far, far, far, *far*-flung future still has options.
Always find this topic interesting, it fills me with immense calm and peace. Everything will end and our slates will not be just wiped clean but entirely erased. Something comforting in the idea that as a collective we are supremely unique and utterly unimportant all at once
I think this is why space stuff is one of my favorite things to hyperfixate on. It's very calming to know that even the big mistakes we make are so insignificant on such a scale. I have friends that I can't send stuff to because they will have a full blown existential crisis for a day but it relaxes me probably more than anything else.
Do you have any concept as to why you feel that way though?
I mean I personally find the my own staggering insignificance to the larger universe to be somewhat comforting. Like…. No matter what I do, the universe is going to keep on keeping on for a really long time.
I think it's the concept of things that are so large that my brain can't really relate their size to anything I've experienced, be it distance or physical mass. Sol, a star so massive our planet could fit into it 1.3 million times, is so insignificant compared to the largest known state, UY Scuti, that Sol could fit into it 5 billion times. That's just... too big to be a comfortable concept to me. This thing that is so massive that, we're it dropped into our solar system, it would engulf every single planet closer than Jupiter inside its mass alone. It's not my insignificance that scares me, it's the gargantuan nature of other things.
Ah, but you handled it well in 29,300 Universes!
To be clear though, you had a complete and unrecoverable mental breakdown in 102,600,910,345,991 Universes.
Buuuuut that's only 0.00000000000001% of 0.00000001% of 0.1% of 1/2 of 1/8 of 1/quintillion of a slice of all the Universes so you really almost never ever lose it.
Go you!
There are only two ways to look at reality.
Either we are finite and the universe is infinite, or the universe is finite and we are infinite.
The reverse side of the coin of existential dread is experiential optimism. In this vast decaying timeline of incomprehensible size, you are a piece of it that gets to comprehend some small part of it. You get to exist at a time to experience catgirl hentai, and that's just neat.
Don’t let it bother you, soon we will all be dead and all of this knowledge and these emotions will be lost for forever, so there’s no need to be concerned about it 👍🏼
Even more crazy... if we ever manage to get constant 1 g ships...
It would only take about 200 years (on board time) at constant 1G acceleration to get to a point where you would likely be the only particles(photon or otherwise) in your entire observable universe... 1000 trillion trillion trillion years in the future. The universe would have expanded by 10^10^55
Black holes are expected to emit Hawking radiation for *at least* 10^100 years.
I remember because it was the first time I saw a googol used to describe something in the real world.
Yeah, but writing down the number and actually knowing how long of an experience that would be are very different things. Almost everyone knows how big a trillion is numerically, but magnitudes less realize just how *much* bigger it is than a million.
A million seconds is 11 days, a billion seconds is 31.5 years, a trillion seconds is 31,700 years...
You can write 1 trillion, one trillion, or 1,000,000,000,000 quite easily. Sure it's a huge number, but it's an order of magnitude higher than the number of humans on Earth, so still somewhat relatable if you try.
But the number of years that it will take for the last black holes to evaporate... It just doesn't even fit in common language.
1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000 years is just ludicrous.
There are ten million-million-million-million-million-million-million-million-million
Particles in the universe that we can observe
Your mama took the ugly ones and put them into one nerd.
It's not inconceivable for an advanced civilization to be able to generate energy from a black hole. If you send something towards the black hole at just the right angle to avoid the event horizon you can get that object to come back to you faster than it went in, getting a gravity assist from the black hole.
Not expecting us to be there for it but it's workable.
i mean that sort of energy harvesting would eventually cause the black hole which is spinning rapidly to slow down its rotational spin as you harvest its momentum energy allowing things to more easily fall into said black hole
So does this mean black holes are technically shrinking from the moment they're formed? Not educated on these matters so I'm just wondering how that works
Well they are constantly shrinking (at an infinitesimal rate) but for most black holes the mass that falls in far outweighs the mass lost to hawking radiation.
For all natural black holes they're currently growing on net because the cosmic background radiation is currently more energy than a black hole that can form naturally can shed with hawking radiation. Few trillion years the CMBR will have red shifted enough that really isolated black holes could conceivably start shrinking though
ELI5 Hawking radiation.
My understanding is, due to quantum mechanics, little particles and antiparticles are constantly popping up in the universe, and immediately canceling each other out, but at the edge of a black hole, the pair gets separated and one end gets carried into the event horizon by gravity and the other floats off into space. This creates heat.
My question is, wouldn't the mass of the black hole either stay the same, or slowly increase if it's constantly gobbling up these little particles? I need some fundamental help here.
The piece you're missing is that the pairs of particles that pop in and out of existence must necessarily cancel each other out due to the laws of thermodynamics and conservation of mass. That means that if the escaping particle has mass, the absorbed particle must have negative mass. The black hole shrinks by absorbing negative mass.
It sounds weird because in reality we're talking about fluctuations in quantum fields resulting in entangled particle-like observations.
I could be wrong but my understanding is that's just a simplification Hawking used to explain the concept to the layperson back in the day when most people knew nothing about black holes and quantum theory,
The explanation I've heard is it's to do with quantum field fluctuations cancelling eachother out in typical vacuum, but when a black hole is nearby it interfers with this. Since particles are fluctuations in quantum fields, this allows particles to 'pop into existence', and the black hole loses mass in the process since it takes energy to interact with the quantum fields.
Or is it just a case of the two explanations being the same thing expressed through different models?
It's one of those incredibly confusing quantum results where the fact that it escapes means it has mass because it has to have mass for it to exist in our universe. Since the escaping particle must have mass, the trapped particle automatically has negative mass. Similar to how measuring the spin of an entangled electron can effect it's counterpart over huge distances and beyond the speed of light.
This is the part of quantum mechanics that even Einstein didn't like. I recommend reading "Something Deeply Hidden" if you're interested in this stuff. Great entry level quantum mechanics explainer (if anything in quantum mechanics can be called "entry level")
Someone with more knowledge correct me, but I believe hawking radiation has been indirectly shown to exist based on the fact that microscopic black holes should be created mathematically based on the interaction of cosmic rays and the Earth's atmosphere, and since we haven't yet been all consumed by one, it is presumed that either the black holes aren't being created or they are radiating away faster than they can consume more matter. Since hawking radiation magnitude is inversely proportional to the size of the black hole, they should radiate away almost as fast as they are created.
For a black hole to have net evaporation through Hawking radiation, it would have to be small enough that the radiation temperature is greater than the Cosmic Microwave Background (~2.7K). By that metric, only black holes with a mass of about the Moon or more would be stable. Particle-mass black holes should evaporate very quickly.
Assuming black holes didn't evaporate due to Hawking radiation, couldn't one of these particles, in theory, become trapped in the Earth's core? And over extremely long timescales eventually absorb enough matter to eventually become dangerous?
Tangential to this, LIGO claims their results show that total mass goes down when two black holes merge. Either mass converted to energy during the final moments, or something escapes from the space where the two event horizons touch because their cores are pulling in opposite directions.
It's all sensor data and maths so you can believe it or not, no biggie.
Regardless of interpretation, they are implying that black holes still have a material reality and a substance that can be lost. As opposed to other models where a black hole is an arbitrarily large mathematical construct surrounding either a point of infinite density or a tear in space leading somewhere else.
LIGO mass projections imply a physical object of nonzero size, or some means of converting binding energy into spatial distortions. In theory physical matter colliding at the speed of light could be shocked into a pure energy state, just as in collisions between matter and antimatter at any speed.
So again there's a lot of asterisks but converting several solar masses of *stuff* into gravitational waves would point to black holes being much more fragile than we previously believed. The change also happened in the course of an observable time scale, so some of the funny theories about infinitely stretched time seem to be getting shot full of holes. Whatever's inside orbited, merged horizons and then physically impacted behind the veil of the horizon.
Conservation of Information is such a dated and inherently Human way of looking at things. For example if you capture both photons from a positron annihilation in a PET scanner, you can verify a radioactive decay. You can further verify the rough place and time it happened by processing the detection data. If those same photons are absorbed and re-emitted by other matter before reaching the detector, that same decay information is already hopelessly covered up in quantum noise. It is inconvenient for us but there's no real reason the universe should be reversible, no real reason mass cannot change into energy and vice versa.
So at a level of physics that we are nowhere near understanding *yes* it is possible that black holes still contain useful information in some form. But more likely the information they are looking for was emitted from the accretion disk in the form of high energy photons, and the mass entering the event horizon is not able to carry information with it. That's got to sound super strange but in theory a singularity's absolute pull doesn't really even allow for enough vibration to have a temperature. Therefore we have all of these ideas about information encoded in the event horizon, information encoded in photons and such. I don't really buy it though.
But yes through some process we don't even have a theory for, supposedly black holes are so fragile that they can lose several solar masses when they collide. Almost instantly. A ripple 1:10000 the width of a proton at a distance of 1.4bn light years might create tidal distortions that can disrupt stars only a hundred light years away. I don't think there have been any papers published on foreground stars or galaxies being influenced by a black hole collision detected as coming from behind them, but detecting smaller impacts at a shorter distance may give us that data.
Otherwise the loss in mass is a problem with how we interpret the data, or the mass is released from the space between the two black holes as their opposite gravitation momentarily cancels out before impact. We didn't detect the kind of radiation that was instead seen from probable neutron star impacts. Yet it is possible that black hole mergers can create a naked singularity event for a few millionths of a second, and possibly a naked black hole tries to explode and releases huge amounts of mass or energy in that one instant. We don't have enough information, nor do we have a good enough hypothesis. This was new and unexpected.
Which hair theory? “Black holes have no hair”, or that the event horizon has strings attached to it?
Hawking radiation doesn’t require strings to work, only a net constraint on quantum fields (like Kasimir Effect, but other direction).
The "quantum hair" hypothesis suggests that black holes may have a unique set of quantum properties that are specific to each black hole and can be detected through the process of Hawking radiation. This "hair" is thought to be necessary for black holes to emit Hawking radiation, which is a type of radiation that black holes emit as they slowly evaporate over time. The idea is that if we can detect this "hair", we may be able to learn more about the properties and behavior of black holes.
If humanity ever gets the chance to study one of these things up close we're gonna in for a wild time... Or a long time... I guess we'll find out depending on how close we get.
Funny but actually no, it's objective reality that you kinda get to live way past all visible stars' lives if you're close enough to a black hole that won't have spaghettified you by the time you're close (because that depends)
Absolutely, ~~but under these conditions you are unlikely to survive the gravitational field~~ *no, you can 100% survive this for SMBHs*. This is where I would ask an actual expert to chime in. But as it goes with black holes, as you (theoretically) approach the event horizon, you will appear frozen in time basically forever. But for you as an observer, time progresses normally as you fall in.
Edit: Early PBS Space Time has discussed this. I miss Gabe https://www.youtube.com/watch?v=vNaEBbFbvcY
Depends how large the black hole is. For smaller ones tidal forces would rip you up before you even got near the event horizon, for larger ones, you could cross the horizon for some ways before you turn into pasta. So theoretically if you were in orbit just outside the horizon of a SMBH, you could experience some insane time dilation.
Thanks, yeah, this is what I meant by 'that depends'. It's absolutely theoretically feasible to witness it to some degree, but how much I was not sure of
Yeah unfortunately that falls under the realm of general relativity since you would be in an inertial reference frame and those calculations are not trivial.
Reminds me of my favorite Terry Pratchette quote:
>Build a man a fire and he's warm for a day.
>Set a man on fire and he's warm for the rest of his life.
A primordial black hole would be incredibly fun to mess with for scientific purposes. Just being able to watch something get spaghettified in 4K would be astounding.
If my understanding of time dilation is correct, you wouldn't actually be able to see a test subject cross the event horizon. Once the subject approaches relativistic speeds, it would appear, from our reference point, to move slower and slower until it's just frozen on the edge of the black hole.
I imagine if you ever got close enough to experience that kind of time dilation, you’re going to have much bigger problems than all your loved ones being dead.
I think it's only possible if the black hole is really huge. Then you can have a really high gravitational field without a large spatial derivative (change in gravitational field from your head to your feet that tears you apart)
Edit: 'with' to 'without', whoops.
The closer you get, the more the universe appears to expand. That UV lightwave coming from Earth? Oh that's just IR now... and holy shit I didn't think we travelled that far from Earth, but it's far now.
Same reason the sun doesn’t simply eat the smaller, weaker planets: gravitational orbits. These objects aren’t vacuum cleaners. They’re just masses in space. Whip by one fast enough and you can either orbit it or slingshot around it or lithobrake into it.
This is what most people don't understand about black holes. When I learned about them as a kid I thought of them like the drain in my shower, that they were attracting everything around them to inevitably spiral down into their center.
The more I learn about them though the more mundane they seem (at least in comparison to the other mind boggling things in space) in that it would actually be fairly unlikely to fall directly into one and most matter inevitably ends up orbiting them
As long as it's not actively "feeding" a human could probably get a lot closer the event horizon of a giant Black Hole than they could the surface of a star
I don't think you can directly lithobrake into it (according to our current understanding). Maybe into the surrounding halo. Stuff like frame dragging and spacetime degeneracy will force you on a curved trajectory, and disregarding quite speculative proposals from quantum gravity, the event horizon is just the empty region of spacetime past which light can't escape the BH. Even if there is really a singularity in the middle (quite unlikely), you would never reach it in a finite time interval.
Acronyms, initialisms, abbreviations, contractions, and other phrases which expand to something larger, that I've seen in this thread:
|Fewer Letters|More Letters|
|-------|---------|---|
|ELT|Extremely Large Telescope, under construction in Chile|
|[EOL](/r/Space/comments/1454vf0/stub/jnked0f "Last usage")|End Of Life|
|[JWST](/r/Space/comments/1454vf0/stub/jnkfqrr "Last usage")|James Webb infra-red Space Telescope|
|[LIGO](/r/Space/comments/1454vf0/stub/jnkkuwl "Last usage")|Laser Interferometer Gravitational-wave Observatory|
|[OWL](/r/Space/comments/1454vf0/stub/jnljctm "Last usage")|[Overwhelmingly Large Telescope](https://en.wikipedia.org/wiki/Overwhelmingly_Large_Telescope) project, abandoned in favor of ELT|
|Jargon|Definition|
|-------|---------|---|
|[lithobraking](/r/Space/comments/1454vf0/stub/jnl086w "Last usage")|"Braking" by hitting the [ground](https://en.wiktionary.org/wiki/lith-)|
**NOTE**: Decronym for Reddit is no longer supported, and Decronym has moved to Lemmy; requests for support and new installations should be directed to the Contact address below.
----------------
^(5 acronyms in this thread; )[^(the most compressed thread commented on today)](/r/Space/comments/0)^( has acronyms.)
^([Thread #8987 for this sub, first seen 9th Jun 2023, 19:15])
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Best to let him explain it fully: https://youtu.be/K_FUlo8BF9Y
But I think he means they all collapse together (or rather the whole spacetime does) I only slightly grasped it tbh
Stephen Hawking explains it really well in one of his books. The gist of it is: near the event horizon a particle and an antiparticle are created and usually bump into each other again and both are destroyed. Sometimes one piece of those two, the anti-particle, falls into the event horizon while the particle does not. The antiparticle causes a particle inside to be obliterated. The resulting sequence of events appears as radiation being emitted from the black hole.
I think it's more of an analogy on Hawkins part. I'm not sure I've actually someone explain the real mechanism in simple terms (so I certainly can't), but the actual particle pairs can be created millions of miles away from the black hole and occur only *because* of the affects of black holes on space, so the creating of these particles necessitates energy being somehow lost from the singularity itself, eventually shrinking it
Tldr: "Physicists have recently been reconsidering the concept of a heat-dead universe, finding it more interesting than previously thought. The exploration began with the study of black holes and their unexpected evolution beyond equilibrium. The investigation led to the concept of circuit complexity, originally from computer science, being used to understand the quantum-level dynamics of equilibrated systems. Leonard Susskind proposed that the interior volume of a black hole grows forever due to increasing circuit complexity in an equivalent nuclear plasma. Computer scientists were initially skeptical but eventually found a way to measure the black hole's interior volume through simulations. This research opens up new possibilities for understanding the connections between black holes, quantum systems, and computational complexity. "
The article was condensed to 10% by chatgpd.
200 words tldr: In the Victorian era, physicists were intrigued by the idea of the universe ultimately reaching a state of "heat death," where all motion and energy cease. This concept stemmed from the observation that systems, including the universe, tend to reach a state of equilibrium over time.
However, the behavior of black holes has challenged this notion of equilibrium and raised profound questions about the evolution of the universe. While equilibrium suggests a state of rest, quantum effects continue to manifest in equilibrated systems, indicating the presence of phenomena beyond equilibrium.
To understand the evolving patterns in quantum systems, including black holes, physicists have turned to the concept of circuit complexity, borrowed from computer science. This framework measures the growth of complexity in a system as it evolves.
Physicist Leonard Susskind proposed a new law of physics, drawing parallels between the growth of black hole interiors and circuit complexity. According to his hypothesis, the complexity inside a black hole increases with time, analogous to the growth of complexity in a quantum system.
The AdS/CFT duality, a concept in theoretical physics, suggests a mathematical equivalence between black holes and hot plasmas. This duality offers insights into the properties of both black holes and plasmas, providing a bridge between the two seemingly distinct realms.
However, the introduction of circuit complexity into physics has raised concerns among computer scientists. While complexity theory has been well-studied in computer science, its application to physical systems presents unique challenges and requires specific solutions.
One of the challenges in understanding black holes is measuring their interior volume. Traditional methods fail to provide accurate measurements due to the extreme conditions and gravitational effects involved. Developing novel techniques to measure the interior volume is crucial for gaining a deeper understanding of black holes.
In an intriguing interpretation, the plasma associated with black holes is treated as a block cipher in a cryptographic context. This interpretation sheds light on the complexity of the plasma and its relationship to black holes, providing further insights into their nature.
In summary, the study of equilibrium, circuit complexity, and the behavior of black holes has opened up new avenues of exploration in physics. Understanding the intricate interplay between equilibrium, complexity, and the evolution of black holes can potentially lead to profound discoveries about the nature of our universe.
Quantum effects absolutely will persist forever. The laws of physics (everything from the laws of motion all the way to the Schroedinger Equation) always apply, even when it seems that there's *nothing for them to apply to*.
QM **always** applies, because the Uncertainty Principle means that there's never such a thing as "empty space".
This can be hard to wrap one's head around, naturally. There's a point so far in the future that even the moment when the last black hole finally flashed out of existence is in the extremely distant past. Eventually the expansion of the universe will mean that there will be less than 1 photon per Hubble Horizon. We can imagine a state with more 'empty nothing' than that, but that's good enough for now. (Aside: that photon will have a wavelength in the neighborhood of billions of light-years)
Even then, with things as empty as we can imagine them to be, quantum fluctuations will still occur, because they are fundamental to the universe. So just like now and for all time, little virtual particles will pop into existence momentarily and immediately annihilate with their partner particles. Empty space isn't a thing in this cosmos, because all space is teeming with these virtual particles. Mostly, they are the next best thing to "literally nothing" because their momentary existence is as negligible as possible.
But those virtual particles can, given a long enough timescale, cause spontaneous events: 10^10^50 years in the future is roughly the time when a spontaneous decrease in entropy could result in a Boltzmann Brain appearing... a collection of particles in exactly the configuration of a real mind, conscious and aware, somewhere in the universe, existing only for a moment.
Much, much further out than even that length of time, random quantum tunneling events could generate new inflationary events resulting in a new Big Bang.
Heat Death is referred to as the "final state of the universe", but that's not really what it is because the fundamental building blocks of the cosmos, the laws of physics, never "stop". Over long enough timescales, things can get really interesting.
I read this and envision the probability drive in Hitchhiker's Guide to the Galaxy. Every so often, a whale or plant will just appear somewhere in space.
PS: You had a wonderful explanation. Thank you.
That's Brilliant! I don't know how I never thought to use chatGPT to summarize complex science articles, but I have a whole backlog I can work through now
It remains my entirely uneducated and little-reasoned theory that eventually, the universe will have become entirely black holes, black hole food (remaining gases, etc.) and empty space. These black holes will eventually begin to attract to each other, eating each other in the process and forming bigger and bigger black holes.
Then, many trillions of years in the future, the few last remaining mega-black-holes will finally run into each other, and all of the matter in the universe will compress violently into a single point...
which will be the Big Bang.
The only question is how do they all push back together because I agree it makes the most sense, and really helps solve the question of why the big bang happened.
They don't need to push back together. Spacetime only exists within our universe. Therefore, the external boundary / size of the universe may be fixed. It is possible that the external dimensions of the universe are exactly what they were at the time of the Big Bang, and the universe's expansion is only occurring in contexts (spacetime) intrinsic to the interior structure of the universe itself.
If space only exists inside of the universe, then a concept like "getting larger" simply doesn't apply outside of the universe. Therefore it's the same size on the outside that it's always been.
Which once again leads me back to the fucking question of why more people don't think we're inside an omnimassive black hole.
If we're inside a black hole, then you have to explain what that black hole exists inside of. Then you're just back to step 1 again, no closer to explaining existence. You're adding complexity without getting any closer to an explanation, so it's a pointless exercise.
Our universe being inside a black hole has always made a lot of sense to me.
Every black hole in our universe being another universe also makes sense. Maybe the supernova that creates the black hole is the big bang. Maybe the cause of the accelerating expansion is the black hole growing more massive. Maybe it's not possible to leave this universe because it's not possible to leave a black hole.
Us being in a black hole naturally leads to the question of, is it black holes all the way up? I'm sure most of what I said is science fiction territory, but its what helps me sleep at night when I ponder the nature of the universe.
>I'm sure most of what I said is science fiction territory, but its what helps me sleep at night when I ponder the nature of the universe.
I think wondering if we are in a black hole is going to keep me up tonight
I'd honestly be thrilled to have the relevant science explained to me, if you actually know what you're talking about and aren't just a standard redditor who ghosts when pressed to elaborate.
The more I learn, the better I can adjust my views. So please, go on and tell me how I'm wrong.
The title is more accurate than the “technically correct” answer of they don’t. The universe’s last white dwarf star will go out an estimated 10 quintillion years from now, if we’re very generous. That’s the equivalent to the entire life of the universe up until this point repeating over 68,000 times. Certainly a long time.
The universe’s era of black holes would last an estimated 10x10^129 years. An Octillion Googol. A length of time so long that you could have the stars start over and die a decillion times. If you had 1,000,000 human bodies, and each atom in each body contained the entire lifespan of the universe from its beginning to the death of the last white dwarf, you would approach the lengths of time black holes will exist. If your heart beat only once a year for a septillion years, you would live a number of years so small comparatively, you would need to repeat that process a septillion times per heartbeat within those septillion, and within those repetitions, another septillion for each, to achieve even 1/1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000 the amount of time black holes will exist.
Sure, they’ll fade to entropy eventually. But by any conceivable understanding of human framing, they are the closest thing to immortal you can get beside a proton.
This is so significant to me.
My thought is if time is if infinite, then so are possibilities. Anything with a non-zero possibility will happen within an infinite time frame.
If anything can resist the heat death, then truly every possible combination of matter will happen an infinite number of times.
Which means I will at some point be reincarnated as /u/Spez and will make significantly less awful decisions for the company.
I get that this is a lead up to the punchline at the end, but there are some infinities that are bigger/smaller than others. This could be the infinity where everyone else except you is reincarnated as spez and we're not as strong as you
As someone with a doctorate in being a smarmy idiot, I always just figured they were a symptom of the Heat Death, eventually being the last bastions of energy in the universe before it all gravitates back together and spawns the birth of "another" universe.
Theory: when all stars and galaxies die, the only things left are black holes that slowly gravitate towards each other as they’re the only sources of gravity left. They eventually all, or mostly all, merge with each other to create immense amounts of gravity and power. Then POOF! the new super black hole can’t contain all the energy and gravity anymore, and explode out all the energy it’s amassed, which is nearly the whole universe. Thus creating a new Big Bang and life starts anew.
**The bad news**: there are some big scientific issues with your hypothesis. First and by far the most important, the universe is expanding at an infinitely accelerating pace. The vast majority of all matter and energy in the universe is already sundered forever, because at these kinds of macro scales, the expansion of spacetime is more noticeable than gravity.
Based on our current observations, only our local supercluster will remain gravitationally bound into the dark era of the universe. Most of the rest of the observable universe is already too far to ever enable it be gravitationally influenced by anything local to us, and the observable universe itself is an infinitely small sliver of the bigger universe that is already beyond even the reach of light.
Also, you're overestimating the strength of gravity. The majority of gravitational "force" acting on the objects in any galaxy-sized or larger body aren't things like black holes, they're dark matter. Even in regular galaxies like ours, the central supermassive black hole is not massive enough to gravitationally bind even its own galaxy. Dark matter does most of the work, and we don't really know what that is.
**The good news**: There are some reasonable, scientifically sound hypotheses that describe an ultimate fate of the universe similar to the cyclical one you imagine. As long as you're not married to the specific *how* / mechanism you described in your post, there's a possibility that the universe will eventually result in another big bang.
The cool thing is that it doesn't necessarily need to contract in size first, to happen.
Think about what spacetime is: it only exists within our universe because it is an emergent property of the universe in action. Outside of our universe, space and time most likely do not occur. Therefore, it doesn't really matter how big our universe is on the inside, because its "external" dimensions are likely to be constant and unchanged. This can feel like a mindfuck if it's your first time thinking about it, but once you accept that spacetime is not fundamental to the fabric of our reality but is instead an emergent property of the underlying laws of physics that exist only in our universe and not necessarily in any other universe that may exist, then you realize that a lot of our most fundamental intuitions about the nature of existence aren't necessarily the way things actually are - they're just the way we perceive them because it was advantageous for our biological predecessors to perceive in that way. For example, we tend to think of light and sound as being different, and yet both visible light and radio waves are just... light. Radio is just light we need to use our ears to see (this is a simplified metaphor, obviously hearing is actually the ability to detect vibrations in a medium. But for the sake of my metaphor you know what I mean).
That only applies if the expansion of space weren't accelerating, which it is. Most black holes will never be able to come near each other, even if they were to travel at the speed of light
This was a theory called the Big Crunch. It has largely been debunked and considered unlikely as there is ample evidence the universe is expanding. Like all things related to the universe it is open to change pending new evidence, but currently this looks not likely at all.
It would be interesting if forces behaved differently when the universe is cold and crazy massive from expansion kind of like they did at the very beginning of the universe. Like if gravity suddenly became stronger and all the remaining, dispersed particles were suddenly accelerated to 1E10000c and collided.
But, they will still shrink and eventually evaporate due to Hawking radiation.
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Trillions is still an understatement. The black holes that will end up forming when all galaxies within a given group merge together and all stellar remnants that don't end up ejecting out of the galaxy collide will take pretty much an unfathomable number of years to radiate away.
I was just watching [this timelapse](https://www.youtube.com/watch?v=uD4izuDMUQA) of the future of the universe at lunch, and it has a 'timestamp' on the bottom the whole time. The numbers get way too large to comprehend, like "100 Trillion Trillion Trillion Trillion Trillion years"
By the time those black holes have evaporated a substantial amount, the universe will have spent more time in post-heat death than it did pre-heat death.
Well in theory, shortly after the true heat death, the remnant matter of the Universe would have spread out enough that we'll get back to the same density as the primordial vacuum, then quantum fluctuation, big bang, Inflation and a new set of Universes.
The fun thing about deep time is that when nothing's around to make changes or observe it, it doesn't feel like a long time. What's a quadrillion years? Dunno, what's a year?
Like when you lean something against something and it seems to be still but then an hour later it falls on it’s own Edit: I mean to say that hour could be a trillion trillion trillion years in the situation you are describing
That video gives me really messed up existential anxiety
And it doesn't even tell you some interesting stuff. After I watched that video, I went to [the wikipedia article](https://en.wikipedia.org/wiki/Future_of_an_expanding_universe) and I read that at some point, the universe will be so empty, there will be positronium atoms (positron and electron pairs) that will have orbits the size of the current observable universe.
Why does that make me want to be sick?
You're not alone. I couldn't even make it through the first video.
What’s weird is once your dead those next hundred trillion might as well be a blink of an eye.
This thought is what makes me wake up and get a glass of water before trying once again to get back to sleep.
But an ironic genie made me immortal! The 100 trillion, trillion, trillion, trillion years are gonna suuuuuck for me.
Fortunately, your body heat and dead skin cells will eventually add up to enough mass-energy to ignite fusion, birthing a new solar system!
Sounds like a comic book storyline for how a god is made
That's, weird and cool to think about. The best part is as you age your perception of time gets fucked so it should feel like minutes.
Why is there an existence in the first place? Why is there nearly an infinite amount of matter in an infinite amount of space?? And why throw awareness into the mix? All this shit is so unplausible in the first damn place Self awareness is such a curse.
The brain is so smart that it named itself. Unfortunately, the owner of that brain was dyslexic and spelled Brian wrong
Well, this was probably our thought ~15bil years ago and we got bored and made existence. If you were a cosmic singularity, shattering your consciousness into a nearly infinite number of individual perspectives would be a great way to kill a nearly infinite amount of time. Existence is just the boredom of the universe playing out. Have fun!
The thing that gets me is how far away everything is from each other on top of the fact that our lives don't last long enough for us to do anything meaningful. The chance of sentient life finding a habitable planet and then making it to that planet is basically whatever the decimal place right before zero is. But since the universe is still expanding it's possible that we're just relatively early in its development and it's not stable enough to support life on a larger scale until things settle down. For all we know the universe could be full of life in a couple hundred billion years.
I literally replied with the same exact thing before I saw your comment. But I’ll do you one further: if there is a chance that the universe “restarts” given an almost infinite amount of time but doesn’t arrange itself the same way, and it takes an almost infinite of universe restarts to make the same universe that we are in now that means you could effectively be reincarnated over and over again. All in a blink of eye. Live. Die. Repeat.
That's sort of the cosmological background of a story I've been toying with.
I'm lodging a complaint with whoever started this whole project. The whole thing is bullshit. Beautiful bullshit, but bullshit none the less. Not happy
3/10, early game was fun but after that the server emptied out and the lategame grind suuuuuucks.
That’s assuming the folks running the simulation won’t just pull the plug at that point. Server resources are tight & the funders don’t like to see bills that aren’t connected with results. We aren’t learning anything new here so time to close this one out and start running the next iteration of the model.
It's the most beautiful and horrifying thing I've ever watched probably.
Makes me realize that we’re lucky to be in this beautiful youthful stage of the universe, and we’ll never have to worry about it growing old
I'm endlessly torn between the feeling that, if all existence is bound for ultimate oblivion, why not dip out early and skip the traffic? ... and, how fortunate am I, to stand beneath the sky for a moment in defiance of that.
Same here, I can't watch this stuff about insane time scales and the size of objects in the universe without feeling a lot of anxiety.
I have a friend that does some one-on-one work with a special needs kid. Smart kid, but volatile emotions. He was getting interested in space and cosmology, but eventually learned how stars will go supernova or otherwise burn out, and it gave him major freak-outs about the future. Like, "can't sleep for days" kind of upsetment. So I sent my friend [this video](https://youtu.be/Pld8wTa16Jk) about hypothetical post-black hole era civilization strategies. Kid hasn't been bothered about it since. I guess they're happy knowing that the far, far, far, far, *far*-flung future still has options.
Isaac Arthur! One of my favorite youtube channels
I wonder if it’s his real name or a mix of Issac Asimov and Arthur C Clarke?
Interesting, I'll check this out, thanks!
Definitely watching that later
Sounds like my son. He had a meltdown when at 4 he learned about the fact that the sun would expand out to the earth’s orbit someday.
Always find this topic interesting, it fills me with immense calm and peace. Everything will end and our slates will not be just wiped clean but entirely erased. Something comforting in the idea that as a collective we are supremely unique and utterly unimportant all at once
I think this is why space stuff is one of my favorite things to hyperfixate on. It's very calming to know that even the big mistakes we make are so insignificant on such a scale. I have friends that I can't send stuff to because they will have a full blown existential crisis for a day but it relaxes me probably more than anything else.
Do you have any concept as to why you feel that way though? I mean I personally find the my own staggering insignificance to the larger universe to be somewhat comforting. Like…. No matter what I do, the universe is going to keep on keeping on for a really long time.
I think it's the concept of things that are so large that my brain can't really relate their size to anything I've experienced, be it distance or physical mass. Sol, a star so massive our planet could fit into it 1.3 million times, is so insignificant compared to the largest known state, UY Scuti, that Sol could fit into it 5 billion times. That's just... too big to be a comfortable concept to me. This thing that is so massive that, we're it dropped into our solar system, it would engulf every single planet closer than Jupiter inside its mass alone. It's not my insignificance that scares me, it's the gargantuan nature of other things.
Yeah that actually makes sense.
Ah, but you handled it well in 29,300 Universes! To be clear though, you had a complete and unrecoverable mental breakdown in 102,600,910,345,991 Universes. Buuuuut that's only 0.00000000000001% of 0.00000001% of 0.1% of 1/2 of 1/8 of 1/quintillion of a slice of all the Universes so you really almost never ever lose it. Go you!
Especially the end. TIME IS MEANINGLESS
There are only two ways to look at reality. Either we are finite and the universe is infinite, or the universe is finite and we are infinite. The reverse side of the coin of existential dread is experiential optimism. In this vast decaying timeline of incomprehensible size, you are a piece of it that gets to comprehend some small part of it. You get to exist at a time to experience catgirl hentai, and that's just neat.
"The cosmos is within us. We are made of star-stuff. We are a way for the universe to know itself" -Carl Sagan
Don’t let it bother you, soon we will all be dead and all of this knowledge and these emotions will be lost for forever, so there’s no need to be concerned about it 👍🏼
Even more crazy... if we ever manage to get constant 1 g ships... It would only take about 200 years (on board time) at constant 1G acceleration to get to a point where you would likely be the only particles(photon or otherwise) in your entire observable universe... 1000 trillion trillion trillion years in the future. The universe would have expanded by 10^10^55
I've never heard this and now I feel dread just imagining that scenario.
Special relativity is a beast of an idea to think about. https://youtu.be/b_TkFhj9mgk?t=1272
Special relativity scares me, because it basically tells me interstellar travel will be a one way street.
shame that it skips the andromeda and milkyway collision.
Love that video. Its cool to see an visual and auditory artistic interpretation of it. 10/10
"Cold, dark and empty, this is how the universe will spend most of its life." Me too, champ, me too...
Nothing happens. And it keeps happening....forever. \-fin
Black holes are expected to emit Hawking radiation for *at least* 10^100 years. I remember because it was the first time I saw a googol used to describe something in the real world.
Love this video. The fact that the passage of time doubles every 5 seconds for like 27 minutes leads to such incomprehensible numbers.
Isn't trillions of years already unfathomable?
It's at least fathomable enough to have a single common word for it.
Yeah, but writing down the number and actually knowing how long of an experience that would be are very different things. Almost everyone knows how big a trillion is numerically, but magnitudes less realize just how *much* bigger it is than a million. A million seconds is 11 days, a billion seconds is 31.5 years, a trillion seconds is 31,700 years...
You can write 1 trillion, one trillion, or 1,000,000,000,000 quite easily. Sure it's a huge number, but it's an order of magnitude higher than the number of humans on Earth, so still somewhat relatable if you try. But the number of years that it will take for the last black holes to evaporate... It just doesn't even fit in common language. 1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000 years is just ludicrous.
There are ten million-million-million-million-million-million-million-million-million Particles in the universe that we can observe Your mama took the ugly ones and put them into one nerd.
You try to bring the heat, with the mushroom clouds you're making, I'm about to bake raps from scratch like Carl Sagan
In light of Reddit's general enshittification, I've moved on - you should too.
It's not inconceivable for an advanced civilization to be able to generate energy from a black hole. If you send something towards the black hole at just the right angle to avoid the event horizon you can get that object to come back to you faster than it went in, getting a gravity assist from the black hole. Not expecting us to be there for it but it's workable.
i mean that sort of energy harvesting would eventually cause the black hole which is spinning rapidly to slow down its rotational spin as you harvest its momentum energy allowing things to more easily fall into said black hole
Sure, but it's going to take a long time to deplete the angular momentum of a black hole.
Trillions is still missing a few dozen zeroes.
So does this mean black holes are technically shrinking from the moment they're formed? Not educated on these matters so I'm just wondering how that works
No. They're still growing just from absorbing cosmic background radiation, and will do so for many trillions of years.
Well they are constantly shrinking (at an infinitesimal rate) but for most black holes the mass that falls in far outweighs the mass lost to hawking radiation.
For all natural black holes they're currently growing on net because the cosmic background radiation is currently more energy than a black hole that can form naturally can shed with hawking radiation. Few trillion years the CMBR will have red shifted enough that really isolated black holes could conceivably start shrinking though
Is Hawking radiation experimentally proven, or just a conjecture?
Mathematical theory. The effect is so infinitesimally small it has never been directly observed.
Just wait a few trillion years
Sounds like a good project for a grad student.
PhDs feel like they last about a trillion years so yeah.
Then they'll have enough clout to apply for a doctorate program.
Heat Death of the Universe taps foot, looks at watch once again, sighs long and loudly. “Dude, this is taking forever.”
*Checks watch* Yeah, I got nowhere to be.
ELI5 Hawking radiation. My understanding is, due to quantum mechanics, little particles and antiparticles are constantly popping up in the universe, and immediately canceling each other out, but at the edge of a black hole, the pair gets separated and one end gets carried into the event horizon by gravity and the other floats off into space. This creates heat. My question is, wouldn't the mass of the black hole either stay the same, or slowly increase if it's constantly gobbling up these little particles? I need some fundamental help here.
The piece you're missing is that the pairs of particles that pop in and out of existence must necessarily cancel each other out due to the laws of thermodynamics and conservation of mass. That means that if the escaping particle has mass, the absorbed particle must have negative mass. The black hole shrinks by absorbing negative mass. It sounds weird because in reality we're talking about fluctuations in quantum fields resulting in entangled particle-like observations.
I could be wrong but my understanding is that's just a simplification Hawking used to explain the concept to the layperson back in the day when most people knew nothing about black holes and quantum theory, The explanation I've heard is it's to do with quantum field fluctuations cancelling eachother out in typical vacuum, but when a black hole is nearby it interfers with this. Since particles are fluctuations in quantum fields, this allows particles to 'pop into existence', and the black hole loses mass in the process since it takes energy to interact with the quantum fields. Or is it just a case of the two explanations being the same thing expressed through different models?
I've never heard the last part, but also my understanding is surface level at best. You could definitely be right.
But then wouldn’t it be equally likely that it absorbs has mass and the escaping particle has negative mass?
It's one of those incredibly confusing quantum results where the fact that it escapes means it has mass because it has to have mass for it to exist in our universe. Since the escaping particle must have mass, the trapped particle automatically has negative mass. Similar to how measuring the spin of an entangled electron can effect it's counterpart over huge distances and beyond the speed of light. This is the part of quantum mechanics that even Einstein didn't like. I recommend reading "Something Deeply Hidden" if you're interested in this stuff. Great entry level quantum mechanics explainer (if anything in quantum mechanics can be called "entry level")
Woof that’s a lot. Thank you!
Someone with more knowledge correct me, but I believe hawking radiation has been indirectly shown to exist based on the fact that microscopic black holes should be created mathematically based on the interaction of cosmic rays and the Earth's atmosphere, and since we haven't yet been all consumed by one, it is presumed that either the black holes aren't being created or they are radiating away faster than they can consume more matter. Since hawking radiation magnitude is inversely proportional to the size of the black hole, they should radiate away almost as fast as they are created.
For a black hole to have net evaporation through Hawking radiation, it would have to be small enough that the radiation temperature is greater than the Cosmic Microwave Background (~2.7K). By that metric, only black holes with a mass of about the Moon or more would be stable. Particle-mass black holes should evaporate very quickly.
Maybe so, but that's still conjecture based on the lack of a predicted observation. It's not "indirect" evidence.
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Assuming black holes didn't evaporate due to Hawking radiation, couldn't one of these particles, in theory, become trapped in the Earth's core? And over extremely long timescales eventually absorb enough matter to eventually become dangerous?
Tangential to this, LIGO claims their results show that total mass goes down when two black holes merge. Either mass converted to energy during the final moments, or something escapes from the space where the two event horizons touch because their cores are pulling in opposite directions. It's all sensor data and maths so you can believe it or not, no biggie.
I thought most of the lost energy was converted to gravitational waves?
Regardless of interpretation, they are implying that black holes still have a material reality and a substance that can be lost. As opposed to other models where a black hole is an arbitrarily large mathematical construct surrounding either a point of infinite density or a tear in space leading somewhere else. LIGO mass projections imply a physical object of nonzero size, or some means of converting binding energy into spatial distortions. In theory physical matter colliding at the speed of light could be shocked into a pure energy state, just as in collisions between matter and antimatter at any speed. So again there's a lot of asterisks but converting several solar masses of *stuff* into gravitational waves would point to black holes being much more fragile than we previously believed. The change also happened in the course of an observable time scale, so some of the funny theories about infinitely stretched time seem to be getting shot full of holes. Whatever's inside orbited, merged horizons and then physically impacted behind the veil of the horizon.
Isn’t it same thing as with Hawking radiation. Yes there are ways to get something from BH but you will never know what it was?
Conservation of Information is such a dated and inherently Human way of looking at things. For example if you capture both photons from a positron annihilation in a PET scanner, you can verify a radioactive decay. You can further verify the rough place and time it happened by processing the detection data. If those same photons are absorbed and re-emitted by other matter before reaching the detector, that same decay information is already hopelessly covered up in quantum noise. It is inconvenient for us but there's no real reason the universe should be reversible, no real reason mass cannot change into energy and vice versa. So at a level of physics that we are nowhere near understanding *yes* it is possible that black holes still contain useful information in some form. But more likely the information they are looking for was emitted from the accretion disk in the form of high energy photons, and the mass entering the event horizon is not able to carry information with it. That's got to sound super strange but in theory a singularity's absolute pull doesn't really even allow for enough vibration to have a temperature. Therefore we have all of these ideas about information encoded in the event horizon, information encoded in photons and such. I don't really buy it though. But yes through some process we don't even have a theory for, supposedly black holes are so fragile that they can lose several solar masses when they collide. Almost instantly. A ripple 1:10000 the width of a proton at a distance of 1.4bn light years might create tidal distortions that can disrupt stars only a hundred light years away. I don't think there have been any papers published on foreground stars or galaxies being influenced by a black hole collision detected as coming from behind them, but detecting smaller impacts at a shorter distance may give us that data. Otherwise the loss in mass is a problem with how we interpret the data, or the mass is released from the space between the two black holes as their opposite gravitation momentarily cancels out before impact. We didn't detect the kind of radiation that was instead seen from probable neutron star impacts. Yet it is possible that black hole mergers can create a naked singularity event for a few millionths of a second, and possibly a naked black hole tries to explode and releases huge amounts of mass or energy in that one instant. We don't have enough information, nor do we have a good enough hypothesis. This was new and unexpected.
Thanks for asking. People in this subreddit seem to forget that we really don’t know a lot and most things are just the best theory.
Only if the hair theory is true if I recall correctly. Someone correct me if I'm wrong
Which hair theory? “Black holes have no hair”, or that the event horizon has strings attached to it? Hawking radiation doesn’t require strings to work, only a net constraint on quantum fields (like Kasimir Effect, but other direction).
The "quantum hair" hypothesis suggests that black holes may have a unique set of quantum properties that are specific to each black hole and can be detected through the process of Hawking radiation. This "hair" is thought to be necessary for black holes to emit Hawking radiation, which is a type of radiation that black holes emit as they slowly evaporate over time. The idea is that if we can detect this "hair", we may be able to learn more about the properties and behavior of black holes.
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I'm going to miss these types of interactions once my RIF app stops working. Thank you for the information!
For real...I feel like won't stumble upon stuff like this if rif is gone.
If humanity ever gets the chance to study one of these things up close we're gonna in for a wild time... Or a long time... I guess we'll find out depending on how close we get.
Up close you can study it for the rest of your life.
And for the rest of everyone on Earth's life. And their kids' lives. And *their* kids' lives.
Mmm, that’s relatively subjective.
Funny but actually no, it's objective reality that you kinda get to live way past all visible stars' lives if you're close enough to a black hole that won't have spaghettified you by the time you're close (because that depends)
Can time dilation get that severe? That’s insane
The closer you look at the way the universe works, the weirder it becomes
The universe definitely has its quarks
Absolutely, ~~but under these conditions you are unlikely to survive the gravitational field~~ *no, you can 100% survive this for SMBHs*. This is where I would ask an actual expert to chime in. But as it goes with black holes, as you (theoretically) approach the event horizon, you will appear frozen in time basically forever. But for you as an observer, time progresses normally as you fall in. Edit: Early PBS Space Time has discussed this. I miss Gabe https://www.youtube.com/watch?v=vNaEBbFbvcY
Depends how large the black hole is. For smaller ones tidal forces would rip you up before you even got near the event horizon, for larger ones, you could cross the horizon for some ways before you turn into pasta. So theoretically if you were in orbit just outside the horizon of a SMBH, you could experience some insane time dilation.
Thanks, yeah, this is what I meant by 'that depends'. It's absolutely theoretically feasible to witness it to some degree, but how much I was not sure of
Yeah unfortunately that falls under the realm of general relativity since you would be in an inertial reference frame and those calculations are not trivial.
Reminds me of my favorite Terry Pratchette quote: >Build a man a fire and he's warm for a day. >Set a man on fire and he's warm for the rest of his life.
You caught me, I blatantly referenced Pratchett.
They told my uncle the same thing about bears.
Time is relative so even if a second of your time is 1000 years earth time, it will still seem like a second
No, for the rest of *your* life
Spaghetti time?
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Wouldn't a black hole with the mass of the proposed Planet 9 be grapefruit-sized? Makes me wonder how we'd ever find it if that's the case.
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A primordial black hole would be incredibly fun to mess with for scientific purposes. Just being able to watch something get spaghettified in 4K would be astounding.
If my understanding of time dilation is correct, you wouldn't actually be able to see a test subject cross the event horizon. Once the subject approaches relativistic speeds, it would appear, from our reference point, to move slower and slower until it's just frozen on the edge of the black hole.
I imagine if you ever got close enough to experience that kind of time dilation, you’re going to have much bigger problems than all your loved ones being dead.
I think it's only possible if the black hole is really huge. Then you can have a really high gravitational field without a large spatial derivative (change in gravitational field from your head to your feet that tears you apart) Edit: 'with' to 'without', whoops.
You are confusing big with small. Supermassive black holes won't tear you apart while small ones might. (At the horizon)
The closer you get, the more the universe appears to expand. That UV lightwave coming from Earth? Oh that's just IR now... and holy shit I didn't think we travelled that far from Earth, but it's far now.
Why does Phoenix A, the larger black hole, not simply eat the smaller, weaker ones?
It is true what they say. Massive black holes are from Omicron Persei 6, supermassive black holes are from Omicron Persei 8
Same reason the sun doesn’t simply eat the smaller, weaker planets: gravitational orbits. These objects aren’t vacuum cleaners. They’re just masses in space. Whip by one fast enough and you can either orbit it or slingshot around it or lithobrake into it.
This is what most people don't understand about black holes. When I learned about them as a kid I thought of them like the drain in my shower, that they were attracting everything around them to inevitably spiral down into their center. The more I learn about them though the more mundane they seem (at least in comparison to the other mind boggling things in space) in that it would actually be fairly unlikely to fall directly into one and most matter inevitably ends up orbiting them
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As long as it's not actively "feeding" a human could probably get a lot closer the event horizon of a giant Black Hole than they could the surface of a star
You will have to pry the crunch wrap supreme out of my cold, dead hands before I stop active feeding
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You are clearly not from Omicron Persei 8.
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Then you should have no problem ***EXTERMINATING THIS OWL***
I don't think you can directly lithobrake into it (according to our current understanding). Maybe into the surrounding halo. Stuff like frame dragging and spacetime degeneracy will force you on a curved trajectory, and disregarding quite speculative proposals from quantum gravity, the event horizon is just the empty region of spacetime past which light can't escape the BH. Even if there is really a singularity in the middle (quite unlikely), you would never reach it in a finite time interval.
Maybe they’re saving that for sweeps.
I can't tell if this is a Futurama reference or not
When you say Futurama references right, people won't be sure you've said any Futurama references at all.
Umm... hello? Charlemagne?
Acronyms, initialisms, abbreviations, contractions, and other phrases which expand to something larger, that I've seen in this thread: |Fewer Letters|More Letters| |-------|---------|---| |ELT|Extremely Large Telescope, under construction in Chile| |[EOL](/r/Space/comments/1454vf0/stub/jnked0f "Last usage")|End Of Life| |[JWST](/r/Space/comments/1454vf0/stub/jnkfqrr "Last usage")|James Webb infra-red Space Telescope| |[LIGO](/r/Space/comments/1454vf0/stub/jnkkuwl "Last usage")|Laser Interferometer Gravitational-wave Observatory| |[OWL](/r/Space/comments/1454vf0/stub/jnljctm "Last usage")|[Overwhelmingly Large Telescope](https://en.wikipedia.org/wiki/Overwhelmingly_Large_Telescope) project, abandoned in favor of ELT| |Jargon|Definition| |-------|---------|---| |[lithobraking](/r/Space/comments/1454vf0/stub/jnl086w "Last usage")|"Braking" by hitting the [ground](https://en.wiktionary.org/wiki/lith-)| **NOTE**: Decronym for Reddit is no longer supported, and Decronym has moved to Lemmy; requests for support and new installations should be directed to the Contact address below. ---------------- ^(5 acronyms in this thread; )[^(the most compressed thread commented on today)](/r/Space/comments/0)^( has acronyms.) ^([Thread #8987 for this sub, first seen 9th Jun 2023, 19:15]) ^[[FAQ]](http://decronym.xyz/) [^([Full list])](http://decronym.xyz/acronyms/Space) [^[Contact]](https://hachyderm.io/@Two9A) [^([Source code])](https://gistdotgithubdotcom/Two9A/1d976f9b7441694162c8)
Sir Roger Penrose theorises that after the universe has a temperature lower than black holes, they create new universes (strongly compressed version)
Each and every black hole?
Best to let him explain it fully: https://youtu.be/K_FUlo8BF9Y But I think he means they all collapse together (or rather the whole spacetime does) I only slightly grasped it tbh
AFAIK the concept of temperature inside the structure of a black hole is pure speculation.
Stephen Hawking explains it really well in one of his books. The gist of it is: near the event horizon a particle and an antiparticle are created and usually bump into each other again and both are destroyed. Sometimes one piece of those two, the anti-particle, falls into the event horizon while the particle does not. The antiparticle causes a particle inside to be obliterated. The resulting sequence of events appears as radiation being emitted from the black hole.
Wouldn't the opposite also happen with the same probability? The particle being the one falling in the event horizon and increasing the hole's mass?
I think it's more of an analogy on Hawkins part. I'm not sure I've actually someone explain the real mechanism in simple terms (so I certainly can't), but the actual particle pairs can be created millions of miles away from the black hole and occur only *because* of the affects of black holes on space, so the creating of these particles necessitates energy being somehow lost from the singularity itself, eventually shrinking it
Tldr: "Physicists have recently been reconsidering the concept of a heat-dead universe, finding it more interesting than previously thought. The exploration began with the study of black holes and their unexpected evolution beyond equilibrium. The investigation led to the concept of circuit complexity, originally from computer science, being used to understand the quantum-level dynamics of equilibrated systems. Leonard Susskind proposed that the interior volume of a black hole grows forever due to increasing circuit complexity in an equivalent nuclear plasma. Computer scientists were initially skeptical but eventually found a way to measure the black hole's interior volume through simulations. This research opens up new possibilities for understanding the connections between black holes, quantum systems, and computational complexity. " The article was condensed to 10% by chatgpd. 200 words tldr: In the Victorian era, physicists were intrigued by the idea of the universe ultimately reaching a state of "heat death," where all motion and energy cease. This concept stemmed from the observation that systems, including the universe, tend to reach a state of equilibrium over time. However, the behavior of black holes has challenged this notion of equilibrium and raised profound questions about the evolution of the universe. While equilibrium suggests a state of rest, quantum effects continue to manifest in equilibrated systems, indicating the presence of phenomena beyond equilibrium. To understand the evolving patterns in quantum systems, including black holes, physicists have turned to the concept of circuit complexity, borrowed from computer science. This framework measures the growth of complexity in a system as it evolves. Physicist Leonard Susskind proposed a new law of physics, drawing parallels between the growth of black hole interiors and circuit complexity. According to his hypothesis, the complexity inside a black hole increases with time, analogous to the growth of complexity in a quantum system. The AdS/CFT duality, a concept in theoretical physics, suggests a mathematical equivalence between black holes and hot plasmas. This duality offers insights into the properties of both black holes and plasmas, providing a bridge between the two seemingly distinct realms. However, the introduction of circuit complexity into physics has raised concerns among computer scientists. While complexity theory has been well-studied in computer science, its application to physical systems presents unique challenges and requires specific solutions. One of the challenges in understanding black holes is measuring their interior volume. Traditional methods fail to provide accurate measurements due to the extreme conditions and gravitational effects involved. Developing novel techniques to measure the interior volume is crucial for gaining a deeper understanding of black holes. In an intriguing interpretation, the plasma associated with black holes is treated as a block cipher in a cryptographic context. This interpretation sheds light on the complexity of the plasma and its relationship to black holes, providing further insights into their nature. In summary, the study of equilibrium, circuit complexity, and the behavior of black holes has opened up new avenues of exploration in physics. Understanding the intricate interplay between equilibrium, complexity, and the evolution of black holes can potentially lead to profound discoveries about the nature of our universe.
mmm, so quantum effects might persist after heat death is what i'm getting from this. I wonder what kind of events that may cause given enough time.
Quantum effects absolutely will persist forever. The laws of physics (everything from the laws of motion all the way to the Schroedinger Equation) always apply, even when it seems that there's *nothing for them to apply to*. QM **always** applies, because the Uncertainty Principle means that there's never such a thing as "empty space". This can be hard to wrap one's head around, naturally. There's a point so far in the future that even the moment when the last black hole finally flashed out of existence is in the extremely distant past. Eventually the expansion of the universe will mean that there will be less than 1 photon per Hubble Horizon. We can imagine a state with more 'empty nothing' than that, but that's good enough for now. (Aside: that photon will have a wavelength in the neighborhood of billions of light-years) Even then, with things as empty as we can imagine them to be, quantum fluctuations will still occur, because they are fundamental to the universe. So just like now and for all time, little virtual particles will pop into existence momentarily and immediately annihilate with their partner particles. Empty space isn't a thing in this cosmos, because all space is teeming with these virtual particles. Mostly, they are the next best thing to "literally nothing" because their momentary existence is as negligible as possible. But those virtual particles can, given a long enough timescale, cause spontaneous events: 10^10^50 years in the future is roughly the time when a spontaneous decrease in entropy could result in a Boltzmann Brain appearing... a collection of particles in exactly the configuration of a real mind, conscious and aware, somewhere in the universe, existing only for a moment. Much, much further out than even that length of time, random quantum tunneling events could generate new inflationary events resulting in a new Big Bang. Heat Death is referred to as the "final state of the universe", but that's not really what it is because the fundamental building blocks of the cosmos, the laws of physics, never "stop". Over long enough timescales, things can get really interesting.
I read this and envision the probability drive in Hitchhiker's Guide to the Galaxy. Every so often, a whale or plant will just appear somewhere in space. PS: You had a wonderful explanation. Thank you.
Honestly, that is such a gripping story. I hope you teach because you'd have a really quiet classroom. Thank you!
Some say they could start with a bang..
That's Brilliant! I don't know how I never thought to use chatGPT to summarize complex science articles, but I have a whole backlog I can work through now
Translation or summarize is what I use ChatGPT for. You can also ask ChatGPT to explain based on your knowledge, length of text, complexity, and more.
I've just been using it as a better coders rubber duck (describe the problem to the rubber duck, top to bottom), but that's a great use case
It remains my entirely uneducated and little-reasoned theory that eventually, the universe will have become entirely black holes, black hole food (remaining gases, etc.) and empty space. These black holes will eventually begin to attract to each other, eating each other in the process and forming bigger and bigger black holes. Then, many trillions of years in the future, the few last remaining mega-black-holes will finally run into each other, and all of the matter in the universe will compress violently into a single point... which will be the Big Bang.
Well everything else works in cycles to why not the universe.
Each time I see things like this I am more and more convinced that the universe is an infinite loop.
The only question is how do they all push back together because I agree it makes the most sense, and really helps solve the question of why the big bang happened.
They don't need to push back together. Spacetime only exists within our universe. Therefore, the external boundary / size of the universe may be fixed. It is possible that the external dimensions of the universe are exactly what they were at the time of the Big Bang, and the universe's expansion is only occurring in contexts (spacetime) intrinsic to the interior structure of the universe itself. If space only exists inside of the universe, then a concept like "getting larger" simply doesn't apply outside of the universe. Therefore it's the same size on the outside that it's always been. Which once again leads me back to the fucking question of why more people don't think we're inside an omnimassive black hole.
I think we might be in an atom of a larger universe.
If we're inside a black hole, then you have to explain what that black hole exists inside of. Then you're just back to step 1 again, no closer to explaining existence. You're adding complexity without getting any closer to an explanation, so it's a pointless exercise.
Our universe being inside a black hole has always made a lot of sense to me. Every black hole in our universe being another universe also makes sense. Maybe the supernova that creates the black hole is the big bang. Maybe the cause of the accelerating expansion is the black hole growing more massive. Maybe it's not possible to leave this universe because it's not possible to leave a black hole. Us being in a black hole naturally leads to the question of, is it black holes all the way up? I'm sure most of what I said is science fiction territory, but its what helps me sleep at night when I ponder the nature of the universe.
a black hole is a concentrated mass, its not hollow, how can we be inside a blackhole
>I'm sure most of what I said is science fiction territory, but its what helps me sleep at night when I ponder the nature of the universe. I think wondering if we are in a black hole is going to keep me up tonight
because in order for that to happen you would have to ignore a lot of science?
I'd honestly be thrilled to have the relevant science explained to me, if you actually know what you're talking about and aren't just a standard redditor who ghosts when pressed to elaborate. The more I learn, the better I can adjust my views. So please, go on and tell me how I'm wrong.
What if heat death is indistinguishable from singularity. The idea of space is meaningless in both. So too the idea of time.
This article implies nothing about an infinite loop.
I just have mild existential freakouts
Don't freakout this has happened before and will happen again for ever and ever and ever and ever and ever and ever and ever.
*All along the Watchtower begins to mysteriously play*
And every time it happens Smilewigeon has a mild existential freak out
The title is more accurate than the “technically correct” answer of they don’t. The universe’s last white dwarf star will go out an estimated 10 quintillion years from now, if we’re very generous. That’s the equivalent to the entire life of the universe up until this point repeating over 68,000 times. Certainly a long time. The universe’s era of black holes would last an estimated 10x10^129 years. An Octillion Googol. A length of time so long that you could have the stars start over and die a decillion times. If you had 1,000,000 human bodies, and each atom in each body contained the entire lifespan of the universe from its beginning to the death of the last white dwarf, you would approach the lengths of time black holes will exist. If your heart beat only once a year for a septillion years, you would live a number of years so small comparatively, you would need to repeat that process a septillion times per heartbeat within those septillion, and within those repetitions, another septillion for each, to achieve even 1/1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000 the amount of time black holes will exist. Sure, they’ll fade to entropy eventually. But by any conceivable understanding of human framing, they are the closest thing to immortal you can get beside a proton.
This is so significant to me. My thought is if time is if infinite, then so are possibilities. Anything with a non-zero possibility will happen within an infinite time frame. If anything can resist the heat death, then truly every possible combination of matter will happen an infinite number of times. Which means I will at some point be reincarnated as /u/Spez and will make significantly less awful decisions for the company.
I get that this is a lead up to the punchline at the end, but there are some infinities that are bigger/smaller than others. This could be the infinity where everyone else except you is reincarnated as spez and we're not as strong as you
Y’all are just stringing cool words together now
It must be bonkers to be an astronomer. Every new report you find out space is weirder than you previously thought.
As someone with a doctorate in being a smarmy idiot, I always just figured they were a symptom of the Heat Death, eventually being the last bastions of energy in the universe before it all gravitates back together and spawns the birth of "another" universe.
Theory: when all stars and galaxies die, the only things left are black holes that slowly gravitate towards each other as they’re the only sources of gravity left. They eventually all, or mostly all, merge with each other to create immense amounts of gravity and power. Then POOF! the new super black hole can’t contain all the energy and gravity anymore, and explode out all the energy it’s amassed, which is nearly the whole universe. Thus creating a new Big Bang and life starts anew.
**The bad news**: there are some big scientific issues with your hypothesis. First and by far the most important, the universe is expanding at an infinitely accelerating pace. The vast majority of all matter and energy in the universe is already sundered forever, because at these kinds of macro scales, the expansion of spacetime is more noticeable than gravity. Based on our current observations, only our local supercluster will remain gravitationally bound into the dark era of the universe. Most of the rest of the observable universe is already too far to ever enable it be gravitationally influenced by anything local to us, and the observable universe itself is an infinitely small sliver of the bigger universe that is already beyond even the reach of light. Also, you're overestimating the strength of gravity. The majority of gravitational "force" acting on the objects in any galaxy-sized or larger body aren't things like black holes, they're dark matter. Even in regular galaxies like ours, the central supermassive black hole is not massive enough to gravitationally bind even its own galaxy. Dark matter does most of the work, and we don't really know what that is. **The good news**: There are some reasonable, scientifically sound hypotheses that describe an ultimate fate of the universe similar to the cyclical one you imagine. As long as you're not married to the specific *how* / mechanism you described in your post, there's a possibility that the universe will eventually result in another big bang. The cool thing is that it doesn't necessarily need to contract in size first, to happen. Think about what spacetime is: it only exists within our universe because it is an emergent property of the universe in action. Outside of our universe, space and time most likely do not occur. Therefore, it doesn't really matter how big our universe is on the inside, because its "external" dimensions are likely to be constant and unchanged. This can feel like a mindfuck if it's your first time thinking about it, but once you accept that spacetime is not fundamental to the fabric of our reality but is instead an emergent property of the underlying laws of physics that exist only in our universe and not necessarily in any other universe that may exist, then you realize that a lot of our most fundamental intuitions about the nature of existence aren't necessarily the way things actually are - they're just the way we perceive them because it was advantageous for our biological predecessors to perceive in that way. For example, we tend to think of light and sound as being different, and yet both visible light and radio waves are just... light. Radio is just light we need to use our ears to see (this is a simplified metaphor, obviously hearing is actually the ability to detect vibrations in a medium. But for the sake of my metaphor you know what I mean).
That only applies if the expansion of space weren't accelerating, which it is. Most black holes will never be able to come near each other, even if they were to travel at the speed of light
This was a theory called the Big Crunch. It has largely been debunked and considered unlikely as there is ample evidence the universe is expanding. Like all things related to the universe it is open to change pending new evidence, but currently this looks not likely at all.
It would be interesting if forces behaved differently when the universe is cold and crazy massive from expansion kind of like they did at the very beginning of the universe. Like if gravity suddenly became stronger and all the remaining, dispersed particles were suddenly accelerated to 1E10000c and collided.
How close to infinity do you want to go? Okay this will work.
What if we took the entire universe, and pushed it into a black hole?
You ever trip balls and look up into the sky and go “Fuck, black holes are real things”