Articles

Could the Universe End by Tearing Apart Every Atom?


Of all the unlikely ends to the universe the big rip has to be the most spectacular. Galaxies ripped to shreds, Stars obliterated cats and dogs living together and then tragically separated by the infinitely accelerating expansion of space on subatomic scales. Good thing it’s not going to happen… or is it? The universe is expanding and that expansion is accelerating and we don’t know what’s causing that acceleration but that hasn’t stopped us from giving it a name we call this unknown influence dark energy. the observed acceleration is for the most part nicely described with a constant density of dark energy the same amount of this stuff in every block of space which means if you increase the volume you increase the overall amount of dark energy hence the accelerating expansion mathematically we describe a constant energy density with the cosmological constant in the equations of Einstein’s general theory of relativity but what if dark energy is not constant what if the energy density in each patch of space increases over time in that case the acceleration itself would be accelerating but that would be bad as long as the rate of acceleration doesn’t increase the accelerating expansion of the universe isn’t a big deal at least for those of us safe and sound in nice galaxies like the Milky Way here the galaxy’s gravitational field is plenty strong enough to resist the minuscule effect of dark energy it’s in the vast tracts of space between galaxy clusters over countless trillions of cubic light-years of emptiness the dark energy adds up the sum of this outward push ultimately overcomes the inward gravitational pull between the galaxies. Galaxies will eventually be so far apart that they can’t see each other let alone fill each other’s gravity but as long as dark energy doesn’t increase there’ll be no expansion inside those lonely galaxies they’ll be safe to fade to heat death as we cheerly discuss in this episode and in fact that’s probably what will happen but it’s fun to think about even worst-case scenarios also there’s a tiny bit of very circumstantial evidence that we might not be so safe from dark energy after all but before we get to the potential disaster of an increasing dark energy and the big rip that follows let’s do a quick refresher on how dark energy works in the language of Einstein’s general relativity I say refresher because we spent a whole playlist delving into the mysteries of dark energy we actually used math the Friedmann equations we’re not going to go so deep here but we are gonna take a quick methy detour feel free to review that playlist before or after if you’re into that sort of thing or you know take a nap and wake up when the pretty pictures come back. This beautiful thing is the second Friedman equation it’s basically the equivalent of Newton’s law of gravity for the whole universe describing the acceleration or deceleration of the expansion rate which depends on how much stuff there is in the universe because this is Einstein’s gravity not Newton’s, gravity is influenced by mass and energy density but also by pressure. Both mass energy density and any positive pressure act to decelerate the universe to cause it to recollapse. In fact for regular matter the effective density is much higher than the effective pressure the ratio pressure over density is basically zero by the way in cosmology we call this ratio, pressure over density, the “equation of state” it’s a simplification of the good ol equation PV Eagles NKT relating pressure volume temperature and the amount of stuff anyway the upshot is that positive energy density and no real pressure leaves the right side of the equation negative so negative acceleration matter on its own can only cause deceleration the expansion rate what goes up must come down. Okay, let’s add dark energy in the form of a cosmological constant it usually hangs out outside the brackets because it’s emo, but we can make it join the party. We can express our lambda as a sort of equivalent mass and pressure in fact, let’s make it an emo party and get rid of regular massive pressure, after all, in the future dark energy will completely dominate the expansion so we have the energy density of the vacuum and the pressure that it exerts but now that pressure term is important the equation of state of dark energy is pressure divided by density equals -1. That just means that as volume increases density does not go down, the basic definition of the cosmological constant. So now the pressure term is A, negative and B because of this factor of 3 it’s a bigger influence than the density so this whole party in the brackets becomes negative – so, emo – that cancels this negative sign and makes the right side of the equation positive. The acceleration is therefore positive which means dark energy is pushing outwards to increase the expansion rate. In fact, any equation of state parameter less than -1/3 would cause that effect. It would mean the stuff is diluted away a little less quickly than the universe expands. In fact, if the parameter is below -1/3 but larger than -1, that’s still accelerating expansion but in that case the dark energy is decreasing over time. The popular idea for that scenario is called quintessence and it’s something for a future episode. For today, let’s push things to the limit: What if we make the equation of state parameter smaller than negative one? How about -1.5; -3; -1,000,000 ? – that’s the case where the density doesn’t just stay constant as the universe expands, but it actually increases. The result would be that the acceleration increases over time offhand, that doesn’t sound so much crazier than regular old dark energy except that it is much crazier. As the rate of expansion increases and with no gravitational bodies left to resist the expansion, all points in space will eventually be racing apart from each other faster than the speed of light. That faster than light recession of space is already happening but right now four patches of space very far apart – like, many billions of light years. If two patches of space are moving away from each other, faster than light, then they can never communicate with each other – the distance from us to the nearest inaccessible region of space is called the ‘cosmic event horizon’. Now, if the expansion is accelerating, then, over time the distance between patches of lightspeed space gets smaller and that is actually happening – your cosmic event horizon gets closer and closer. Eventually, we won’t even be able to see the nearest galaxies because they’ll be moving away too quickly. But as long as we have a nice gravitationally bound galaxy to live in, the cosmic event horizon can never shrink to a size smaller than that galaxy. That’s not the case if dark energy increases. After our galaxy is disrupted by the increasing dark energy there’s no protection from the encroaching cosmic event horizon. The final result is that no particles will be close enough to interact with each other, ever. So, protons and neutrons will be separated into their component quarks… That is the big room scenario, It happens when the cosmic event horizon is smaller than the smallest possible structure. What could cause something like this? No idea. No one has any idea. That doesn’t stop us from giving it a name, we call any dark energy that increases in strength – so with an equation of state less than -1, ‘phantom energy’. That name seems to have been coined by Dartmouth physicist Robert Caldwell in a seminal 2002 paper, “The Phantom Menace” – and that was three years after the theatrical release and I guess we still thought it was a sign of the end of the universe. So let’s see what this made up math has to say about when the big rip would happen. Any equation of state parameter smaller than -1 means a big rip. The smaller the parameter, the sooner it happens. Caldwell does this calculation for the case of W=-1.5 In this scenario, the big rip happens in twenty two billion years from now. Things don’t get really messy until near the end, around a billion years before the big rip, galaxy clusters are ripped apart. At 60 million years and counting, the Milky Way is shredded. Now, this doesn’t mean that the cosmic event horizon is quite inside the Milky Way just yet, just that the effect of phantom energy is stronger than the gravity binding the stars together. In fact, at this point the cosmic event horizon is still about 200 million light years away. And so there should be a handful of galaxies still visible to us. There are some millions of years of fun as we watch those galaxies disassemble and the constellations of stars in the Milky Way fly apart. The final deadly stage only happens in the last month or so when the solar system is pulled apart. In the last 30 minutes phantom energy is strong enough to overcome Earth’s own gravitational binding energy and the planet is disrupted. Moments later at the 10^-19 of a second, before absolute disruption, it will overcome all chemical bonds then the forces binding atoms together, then nucleons, and then presumably anything smaller. In its final state a big rip universe will be nothing but hopelessly isolated elementary particles separated by infinitely expanding space. That’s a hell of a story. How sure can we be that it won’t happen? well, somewhat – mostly. Our efforts to understand the nature of dark energy are focused on measuring the value of this ‘equation of state parameter thing’. We can do that by combining all of the clues to dark energy’s behavior. For example, in the patterns of the Cosmic Microwave Background, in the baryon acoustic oscillations and in supernovae – We’ve talked about all of these thing before. Combined with a few other measures these tell us that the equation of state of dark energy is very very close to -1. The plunk science team calculate -1.028, plus or minus, 0.032 – Phantom energy is still a faint possibility but even at its most extreme from the planck estimate, the big rip would be around 75 billion years away. Time to get our affairs in order. But more likely is that W is exactly -1, meaning dark energy is constant for three reasons: first, it seems too much of a coincidence that it should be so close to negative one without being negative one. Second, there’s a plausible physical explanation for a constant dark energy that the vacuum has a set amount of energy per volume. There are at least some physical ideas for that. As far as I know, there aren’t serious ideas for an increasing dark energy. And the final reason to hate on phantom energy: it violates energy conservation in a way far worse than regular dark energy. It violates the same energy conditions of general relativity that prohibit negative mass and time travel. Ok, so, after all that hate let’s finally get to the one significant result that suggests dark energy may be increasing after all. In fact, we’ve already covered it in our recent journal Club episode. The acceleration rate measured using distant quasars hints at an equation of state parameter slightly less than negative 1 well they’re not yet with enough significance to overturn all other results. Probably, probably – the universe will still end in a long cold heat death in which the stars of our galaxy wink out become black holes and then evaporate over an unthinkably long future. But maybe if you believe in phantoms it’ll all be over much sooner when the universe is ripped to shreds by the infinitely accelerating subatomic structure of space-time. Last week we did a spacetime journal Club on that paper that actually presented evidence that dark energy may be increasing in strength based on measurements of distant quasars. Lots of fun discussion ensued. A few of you asked a great question: “What happens when the big rip tries to separate quark pairs?” For background, when you try to separate composite quark particles – hadrons, the energy put into breaking the bond just generates new quarks – so you just get more hadrons. Dot follows up by answering the question with a detailed internet search. Meaning, I don’t have to answer it. Thanks Dot! …but to summarize: The answer is: maybe? Depends on whether the splitting hadrons can keep up with the exponentially increasing dark energy. The final possibility that Dot found is the most fun – that the exponentially increasing dark energy leads to exponential particle production, which ends up looking like a new Big Bang. Sounds cool, but be cautious of theories that seem crafted to give happy endings. We should do a statistical analysis of cosmology papers that predict saving the universe versus it dying horribly. I’m guessing the save the universe theories are more numerous than their plausibility warrants. Tony Stark asks, “if dark energy changed in the past, can it also change in the future?” In fact, if it changed in the past then we expect it to change in the future – at least according to the standard/non-standard models of changing dark energy. It could be increasing in the future, that’s phantom energy or it could be decreasing. But even if dark energy is decreasing and decreases to zero – in fact even if it became zero tomorrow, the universe is now expanding too fast to ever recollapse. The amount of mass and energy it contains just doesn’t provide enough gravity. On the other hand, if dark energy evolved into an attractive rather than repulsive force, who knows! There’s no good reason to believe that it will but we also don’t know what dark energy even is – so, live in hope. Onehit Pick notes that dark energy backs up their hypothesis that massive dinosaur fossils were actually originally chicken sized. The tiny bird bones grew with the expansion of space. Checkmate, evolutionists. They would also explain how they fit elephants on the ark and those extra pounds I put on over the winter.

100
Comments
  • So, if all the theories and predictions are right, an atom in my body was at some point at the same place with the atoms in the Andromeda galaxy, and eventually an atom in my left hand will be separated by millions of light years from an atom in my right hand.

  • If dark energy were to disappear completely tomorrow, would space time continue expanding at its current rate (maintain the same velocity of expansion, obviously without acceleration) or would it halt completely? In other words, does space time carry with it momentum in the same way that matter does?

  • Yo @PBS Space Time Dude With Beard. At 9:48 I don't think we'd see the other galaxies split apart. If we did, they'd see ours split apart too. And at 1.5 I think thats beyond the CEH, right?

  • Many find the big rip terrifying. But imho it's likely to be the next big bang. If space-time can be torn apart by gravity – then why can't it be torn apart by expansion?
    A moderate expansion is fine but finally the day will arrive where expansion is so rapid that not only atoms are torn apart – but space time itself. What will happen then is anybody's guess but my guess is that it'll trigger a new big bang. Space-time is torn apart and creates new fundamental particles – a new big bang is born.

  • I like the idea of people being scared of something that, if it is true, will happen billions of years from now. I don't know about all of you, but I'm not planning to be here to see that. Not even close. If you're reading this comment in 2119, I'm already long dead, but it would have been nice to know you. If you are reading this comment billions of years from now, I'm honestly surprised that this message survived and that you can actually understand it. If you're capable, maybe you can revive me so that I can meet you? Be warned, I'm gonna look pretty strange to you.

  • Was not the earliest calulation that big rip will start when the universe is 20 billion years but if universe is already was 18 billion years in the new discovery that universe is a sphere – ( if time was accelerated in early universe -you cant see? it just as you cant see the 3d strecthing by a gravitywave ) so big rip already started -boetes void would be a place to watch for it.

  • What was the point of being condescending to your viewers? Whether someone is smart enough to understand the math, or just wants to try to, doesn't give you the right to be a dick. I am quite honestly shocked that you said that, considering how wonderful your series is and its support of learning….

  • Well if dinosaurs were as big as chickens why arent we then? If universe was expanding then wouldnt the dna and our cells and everything else be in the same ratio??

  • Didn't people use to think the universe was like a piece of elastic that would expand till eventually it would stop and begin to crash back into the centre

  • If the protons and neutrons get ripped into quarks then the universe will be filled with quarks because the energy that dark energy exerts on the quarks will create new quarks

    If I’m wrong please tell me why

  • 8:22. theres the answer right there.
    "no idea. nobody has any idea."

    its all a load of BS.

    8:53
    "made up math".

    thats all maths is. made up.
    once upon a time, people like faraday just worked things out by experimenting. no-one was giving suitable answers, and the answers they gave tended to be "read the bible". now we just get told "read more books on physics" but the answers are still often as unsuitable.

    now we throw stupid equations around, say we cant break the laws of thermodynamics yet propose bullshit theories that do exactly that, and of course… wasnt the cosmological constant einsteins "greatest blunder"? oh, but now we need it because our maths is starting to show major cracks in its facade.

    notice they want to change certain constants, just like they changed a few others so noone can have errors with the speed of light anymore because we measure length based off light and measure its speed using length based off its speed… problem solved. measure something by using itself to measure itself…

  • https://youtu.be/gEyXTQ9do-c?t=623 how does expansion overcome color confinement without just creating a volume of quarks that have "absorbed" that vacuum energy and slowed it back down with the new mass.

  • What about rather than being an energy, that its an attribute of space, which makes space self replicate. Yeh it doesn't fit in with Einstein but it would explain why the expansion is so uniform and acceleration 1,2,4,8,16… How it would work with time, I don't know but I also don't understand what space is, I use to think that space was nothing but I now know it is something but what is that something. Appologies that I haven't done a good job of communicating this thought

  • If the space is increasing faster than light can dark energy be faster than light ? A dark energy detector could see beyond the cosmic horizont ?

  • There isn't gonna be a rip.. And we are proberly not in a universe.. The universe as we call.. Its light that hasn't reached us yet.. Its a possible reason.. So this is irrelevant..?? ?‍♂️?‍♂️

  • The universe begins with 0 density objects and ends with very heavy, extremely dense objects. It begins in multiple times and locations and ends at multiple locations and times.

  • Infinit acceleration can not ripping the field, only everything will be transformed to the energy. And this situation will be start of a new big bang.

  • Alien kid in moms basement: Creates universe on a computer
    Alien Mom: :"Billy, Dinner time"
    Kid: "Ok mom be right there"
    Mom;…"Billy?"
    Kid: "Hold on mom I have to save my game!"
    Alien Dad: (pull power cord out of the wall)
    Universe dies
    Kid: "DAD!!! Ugh Now I have to restart the whole game!!!"

  • why does the milky way still look the same in the pretty graphics. where is milkdromeda? by that time we should have milkdromeda.

  • I don't believe that negative energy exists rather the universe has a slightly curved geometry which pushes matter away in all directions

  • Lesser intelligent minds don't understand that the universe isn't expanding, it's…..it's more like being created 😉

  • @PBS Space Time
    About "save the universe theories":
    Isn't it the most plausible explanation if the creation of our universe was the product of a very natural occurrence such as an ever repeating loop of big rips and big bangs?
    It would be a ridiculous coincidence that the only universe that ever came to exist was also picture perfect for the existence of (intelligent) life.

  • мне кажется команда Планка прав – 22 миллиарда лет более приблизительна… но человечество может от крыть новые миры максимум за 1,5 миллиарда лет и сумеет взять под управление все процессы связанное с нашей вселенной…

  • I wonder, If the Big Rip really happens, would black holes be ripped apart or not? Perhaps as the space gets 'stretched' the event horizon shrinks (maybe the Big Rip speeds up Hawking radiation? I really don't know and I think you'd need a theory of quantum gravity to get an answer) And when the event horizon shrinks to below the scale of nucleons, what happens when you pull the quarks apart? In experiments pulling quarks apart creates new quarks due to confinement. Thus, wouldn't this result in endless production of new matter, the phantom energy converting into quark mass energy ? It sounds almost like a new Big Bang. Maybe the Big Rip wouldn't be such a bad scenario.

  • If the universe tears quarks apart from the particles they compose, it'd just create new quarks. This'll dramatically increase the amount of mass in the universe and it'd likely reverse the polarity of the neutron flow… er I mean it'd reverse the big rip.

  • The energy parameter is exactly -1. I am 74 and looking forward to seeing the end of the universe, but eventually there will be not enough mass/energy density to support a thought.

  • I don't think that it's unwarranted to think of "save the universe" scenarios. I think it makes far more sense for there to be matter forever through some sort of renewal process than it ever would for matter to only briefly exist. I think there is going to be "stuff" indefinitely. It doesn't make enough sense to me that "stuff" came to exist and then went away. I think it requires way more explanation to describe "Why was there only stuff for a short period of time" than to describe "Why is there all this stuff!?!?". Besides, basically everything we've observed in our lives has been some kind of a cycle. I think it makes sense for that to, somehow, describe the universe as well. But I don't know how, specifically. We can all come up with tons of wild ideas about that but personally I'm not sure we'll ever be able to test any of them conclusively. It's like asking if a process inside your computer is able to break its boundaries and explore the rest of the system. Yes, they can, because software and operating systems are flawed and have exploits. But does reality itself have exploits?

  • Excellent video. Many of Robert Caldwell's relevant papers may be found at arXiv.org , including the paper mentioned in the video, #0302506, and a relevant earlier paper on the Phantom Menace, #9908168.

  • What if, you could use probability, and a time machine? If A destination then B before you walked out. If destination B then A. Finish line send message to correct condition. An infinite loop with two destinations to infinity.

  • Wouldn't tearing up matter by space time expanding from within, should have to be somewhere above Inflation Phase Big Bang Velocity…

  • "Could the universe end by tearing apart every atom?" Nah not really. Its more like every fermion get its boson and they start to copulate and then a giant coherent orgasm happen and a new big bang start anew. Hypothetically. I call it the cosmic orgy scenario.

  • Anything to do with hugely distant quasars happened billions of years ago…so does anyone know what's happening right now at those billions-of-light-years distances? Or can we know? If the universe were ripping itself apart right now, or collapsing at light speed right now billions of light years away, we won't know it until it hits us. Then it's game over.

  • Hallo vi ved jo virkelig ikke hvorfor vi eksistere, alle gentager og gætter. Ingen kommer til at vide og forstår sandheden. Vi sikkert en form for simulation af en slags.!! Hvem ved.!!

  • It takes someone and something to make something else ! Same as it takes something to move something else ! that's why sciencetice get alot of things wrong!

  • While I love your program and gain significant insights, could you not mock Judeo/Christian beliefs?

    That would be great. Thanks.

Leave a Reply

Your email address will not be published. Required fields are marked *