Ep. 801: The Beginning & End of Everything - Part 2

0:00Oh A astronomy cast episode 801 the end of the universe. Welcome to a astronomy cast for weekly facts based during the cosmos where we help you understand not only what we know but how we know what we know I'm Fraser

1:01Kane I'm the publisher of the universe today with me is always this Dr Pamela Gay a senior scientist for the planetary sciences and the director of Cosmolest Hey Pamela how are you enjoying our new ad free existence? I am still absolutely terrified about making payroll right? Yes terrified about making payroll of Viva Ali Rich are dear they will be paid I yes mace slowly die inside until we get more patrons but we we trust all of you yeah we trust you to join us we I think yeah we're in this I know exactly I was in that spot yeah we choose that you're like okay fine I'm cutting the ads I can't take it anymore I like you sick or swim this is it this is putting all of my I'm pushing all my chips in and to mangle all the analogies and I trust that we have produced a quality enough show that that our audience want to come along with us and you you haven't

2:03reached the serenity part but at least we've reached the I don't have to think about ads part which feels great right you know we'll get to the I don't have to think about ads safely part but that comes that comes next right and I have give a shout out to everyone who's watching this live over in the YouTube chat I have people making me hungry by making references to the restaurant at the end of the universe right I have folks over in Twitch filling my head with song lyrics as they talk about it's the end of the world as we know it yeah you feel I feel fine we have the best chat on the internet yeah so just if you want to join our patreon help us you know any amount because you know come into the three dollar level um that makes a huge difference go to patreon.astronomycast.com or astronomycast.com no sorry or patreon.com slash astronomycast either of those work today we do the sequel to our two part series we jump to the end of the universe and all of the

3:05major moments it will occur from now until the heat death of the universe the end of everything all right Pamela uh so now we like we last episode I was just like speed ran through you know star formation galaxy formation planets life yeah technology you know just whatever blips now let's cast our eyes forward into the future of the universe what would you say is the sort of the first major uh you know now we're starting to enter the the end stages of this universe that we live in so there's there's so many different ways to look at that there there was a planetarium show I saw when I was in college that that was the story of a sci-fi future where all the stars have shut off and and so that really starts to feel like the end but other people I know will

4:08say the end is when expansion has carried everything away so that that future milk drama to combine galaxy is the only thing in our sky I don't know what you call the beginning of the end okay fine I will tell you I was I was hoping to sit you up but clearly you can't decide so you know if you wonder if there's like the episode kind of script we do not so all right I'm going to start with the beginning of the end about the end of the Milky Way as an isolated galaxy all right so as the story goes about five billion years from now our galaxy and the indromeda galaxy which is hanging out able to be seen with your unated eye they're gonna undergo some things and become a single galaxy probably more elliptical in nature and then hang out

5:09and before is going to join the party all the dwarf galaxies are going to join the party yeah and and like don't we know that there was like one paper that suggested that in fact and drama the won't merge the Milky Way in all chances there is a chance that in drama the will skip off that they will they will be separate fine don't tend to see email we know about the research but we're just going to go with the cool one which is that they merge into this giant elliptical galaxy think m87 but you're living in it it'll be smaller than m87 but we're living in it yeah and at this point in time we're we're going to be heading in towards other galaxy clusters but as that happens it turns out the universe the expansion rate is going to carry us away faster than we're falling in right and and that means we never get there we never get to join the cool kids in the big galaxy cluster and that's okay that line is about

6:12five million light years so so there are galaxies big sort of three to five like and drama is two and a half million lighters away from us and thirty three is kind of in the same yeah yeah um and that then the closest galaxies are on the sort of five million light year range and it's believed those ones are sort of the momentum left over from the big bang the acceleration caused by dark energy are going to push those galaxies over the cosmic horizon that we will never but we were the gravity is trying but we will never merge with them as well so we will just become more more isolated over time and in the way to think about this is imagine that you're trying to run against a moving walkway if the moving walkway and we've all seen little kids trying to do this with escalators yeah yeah little kids not grown adult men in their

7:15fifties do this but yeah go ahead okay fair fair enough yeah I do this if if a a human being or other creature with legs attempts to go against the motion of a moving walkway of an escalator if they are fast enough they can reverse directions and run against the flow of motion and get to where they're trying to get if they can't move fast enough and we've all seen little kids go through this they end up either it appears like they're running in place because they just can't get ahead of the motion because they're moving at the same rate as the motion or they're moving for all their worth and still getting carried backwards and as the universe continues to expand it's going to be like a little kid getting tired and first making progress and then holding still and then falling away as everything disappears out

8:20of our sky every moment of time we luckily are unaware of this because it would be existential dread we are seeing a slightly different part of the cosmic way of background we are seeing a slightly different part of the universe as things get carried away from us yeah and so you know that merger with endromeda yeah and that the correct technical term is milk drama as you said yeah if anyone says milk of media they're wrong it's milk drama um that's about five billion years from now so you know like when the sun is starting to consider the end of life yes is when we will begin our merger with endromeda or not whatever don't have any emails um but that isolation that you're talking about that point where the galaxies fall over the cosmic horizon that's more like a hundred and 150 billion years from now yeah and and this always leads to the sort of like the beginning of this kind of existential crisis where you say like a future astronomer someone who shows up at that time in the universe

9:24will have no evidence will we will build a big telescope and they won't see anything there will just be the stars in the galaxy there will be maybe the last few dwarf galaxies that have finished haven't finished merging and they'll look off in all directions there we know evidence of galaxies so so a manual Kant was actually a physicist we remember him as a philosopher but he was a physicist and he's the person who looked at all the different nebulae that were being discovered by folks like Herschel and Messier and looked at the endromeda nebula at the time was what they called it yes and said the only way we could explain its shape is if it was another island universe and so this idea that galaxies are island universes was first come up with by monol Kant and in that future that we're looking at our milk drama to galaxy will be the entirety of our visible universe so it

10:25truly will be an island universe and other I believe it would be a waste of space if there's another civilizations out there other civilizations will each be in their own island universes and yeah that's only a little bit depressing science doesn't care yeah I know I know I know yeah we can get used to it like this whole episode is going to feel sad and existential but you know we'll do with the smile um and so there will still be evidence that like if you build a powerful enough detector something that is the equivalent of looking for the cosmic microwave background radiation you will pick up this glow in all directions that is the sort of the last light that was sent by all of these galaxies that fell over the cosmic horizon the cosmic microwave background radiation will still be there it will just be red shifted so far you'll need gigantic telescopes that that you will be able to detect that there is something outside the

11:28galaxy you know maybe a trillion years into the future and and the thing to also think about here is that cosmic microwave background that we see today as microwave it didn't start that it started much much hotter it started out in the ultraviolet now as the universe continues to expand and continues to expand and continues to cool we're going to see the cosmic microwave background slipping to longer and longer wavelengths as the universe in the background slips to longer and longer temperatures cooler and cooler temperatures so so it'll never go away right but it will but it will be effectively undetectable by technology yeah and you'll sort of you'll sort of get to this place where the the universe is cooling down faster than the technology can advance than the telescopes can be built and grow you know you need to build a telescope that is an

12:29interferometer that is a light year across to detect the cosmic microwave background radiation with wavelengths that are whatever a light year long and it's not like we're going to have a whole lot of energy for these future civilizations to be basking in either that's another problem well now we've moved to the next step which is that that the power the stellar engines of the universe will wink out one after the other and we we already can see places where star formations ended you look at globular clusters no star formation you look at some particularly have had no recent consumption of other galaxies elliptical systems and there's extraordinarily limited star formation going on one star formation ends you're in the cool down period after a while so your average star it's going to go through its life it's going to eventually exhale it's out our atmosphere that atmosphere is going to drift away as a planetary nebula

13:35you might get lucky and have a supernova which is a bit more exciting but this material that is drifting away isn't going to form these high density star forming regions because some of their mass just isn't getting to go back out there into the mix it's getting left behind in the neutron star and the white dwarf and the black hole and so you have a more and more diffuse background of material out there with embedded nuggets of cooling diamonds of cooling neutrons and as all of that heat just slips away we we start to see more and more of what's called the heat death of the universe creeping up on us and this is where things start to get messy because protons don't behave as predicted right but I want to put it I want to sort of head yeah you should do wait got let us okay because we don't have a script and we don't have an outline

14:36shared outline we have no idea what we're going to talk about yeah we keep real so so you're talking about sort of like essentially the death of all stars and the longest lived red dwarf stars will list will live maybe 10 trillion years and those galaxy collisions will inject fresh material into the galaxies that you'll have pockets of star forming material that will eventually find the level of density required to form stars but you will get to about 100 trillion years from now yeah and that will have all been used up whatever galaxies were going to collide will have collided whatever stars that we're going to inform that even the smallest possible red dwarf stars will live out their lives and about a hundred trillion years from now the last star will die and there will be no more stars and and by die we mean we'll cease having nuclear

15:41reactions generating new energy through fusion right and and so they will continue to radiate heat as they cool and and this is where with the white dwarfs like our star they end up as carbon white dwarfs which are essentially diamonds so that's kind of cool to think about super cool yeah one little moment just like one more happiness yeah yeah yeah in what is a sad and depressing right right and and those will eventually get cool enough that you could actually like hold your hand as it gets gravitationally destroyed up to the diamond but it wouldn't get burned just gravitationally destroyed in a big deal yeah and and those little red dwarf stars depending on how little they are going to end up as either helium or higher atom white dwarf stars because they they're fully convecting their lava lamp stars and and once they have completely mixed and used up everything they just they're like oh no more and collapse yes and so so this

16:45is known as the degenerate era the previous was the the still left fris still the fariest still I believe these words for you yeah all right the stilliferous era with the star you know the time when stars can form yeah and now we've reached the degenerate era and so all stars have turned into white dwarfs or neutron stars or black holes yeah it's all you've got you've got galaxies where you've got a supermassive black hole at the center you've got stellar mass black holes neutron stars and white dwarfs that are orbiting around this central supermassive black holes but this is not stable and so the three body interactions between these objects will pluck away these objects one to time and send them on escape trajectories out of the galaxy and so over the you know now the numbers are gigantic right like we're we're in the degenerate era you

17:45know 10 to the power of 19 you will end up with every star every white dwarf every neutron sorry every black hole is still a mass black hole that didn't get absorbed into the supermassive black hole at the center is now going to just be had will fall over its own version of the cosmic horizon get caught up by dark energy expanding away from everything else and so everything will be in its own pocket universe effectively there will be supermassive black hole universes there will be stellar mass black hole universes there will be they're not really universe but like just practically there will be nothing around these things yeah now you can jump to proton decay okay fine if it exists fine so so after all of these three body interactions after all the mergers then if grand unified theories can ever be made to work every single one of the grand unified theories so far has made the prediction that protons will decay into energy just switch it

18:58entities and we have been watching them in a massive vats of liquids where we're also looking for other high energy particles where we're looking for a matter where we're looking for neutrinos and you can either watch one proton for 10 to the 30 years which I do not recommend doing that's a lot of time or you can watch 10 to the 30 protons which we're aiming to get towards or somewhere in the middle you watch 10 to the large number of protons for years I love that though you watch 10 to the 30 protons for a year yeah you watch you know right watching for 10 to the 30 years watch every proton for 10 to 30 years you pick yeah and so we pick to go with vast vats and watch them for long periods of time that are not as long as 10 to 30 years um but so far the protons are like no I will not and they are sitting there being extremely stable yeah and and so the question

20:04starts to become if every single path we've gone down trying to create a grand unified theory that requires these suckers to be unstable is wrong because the protons are like now won't do it um then what happens yeah and and this is where we could have a future of just like cold diamonds in the universe hmm yeah that's kind of awesome it is kind of awesome and it is another little glimmer of hope yeah you'll be left with a cold dead diamond in the universe and not a background glow of additional energy when all of the protons that made up that giant diamond evaporated into nothing um that that would be great but but the evaporation is coming so so we're gonna get to to that in a second so so we are now like what 10 to the 40 years of the protons do you go you said maybe 10 to the 30 yeah maybe it's 10 to the 40 all the protons we have run out of words that get used in common conversation for how far in the future this is

21:07yeah this is like a super guttillion years I believe is the technical term for this um but yeah we have lost like all the protons have either given up the ghost and null decayed yeah they've held together laws of physics we will figure out what that will be right before that actually happens we'll keep you up to date but if they do decay then all of these objects so so the black holes are gonna evaporate no matter what they're sitting there well as well you're already jumping ahead going back to the protons going back to the protons okay so so all of our little white dwarf stars all of our neutron stars um are are going to so at the surface of neutron stars the densities are low enough that you have have neutrons break apart into protons and electrons if the protons are unstable protons end up radiating away white dwarfs made of protons and electrons protons radiate away and you end up with this background ghost of energy kind of permeating everything as

22:14the universe works on experiencing extreme amounts of entropy um so we're considering a future where where basically the energy is so diffuse that it can't clump up anymore and the universe is so vast that the speed of light means nothing can yeah even communicate anymore and and so if protons decay we are looking at just this diffuse energy punctuated with supermassive black holes still getting their supermassive black hole on and so to take that analogy that I was giving earlier about how essentially every every white dwarf ends up in its own isolated observable universe every photon yeah of decayed photon yeah well every yeah we'll end up in its own observable universe

23:19that all of the other photons that were made up from that white dwarf that decayed yeah we'll all expand away from each other at the speed of light to the point that you will have an observable universe for each one and there will be nothing in your observable universe yeah and before you start adding us we're going to get to the big rep just hold on okay we're going to go with the kinder jontler universe and first yeah yeah I guess um it's all right so all the relief now is the the decayed protons yeah and the black holes yeah and and black holes disappear at different rates depending on their size yeah so any microscopic black holes left over from the formation of the universe have already bit the dust any current black hole of noticeable size is absorbing mass energy from the cosmic micro background and everything else so that it's decay isn't causing it to to like obviously lose mass so that's not a concern in the modern universe but as the universe

24:24expands the feeding of black holes comes to an end right and when you stop feeding a black hole it starts losing energy and energy in mass of the same thing yeah and over time through this radiation of Hawking radiation they get smaller and smaller and smaller until in a flash they cease to exist right and that number depends on the mass you said that depends on the mass of the black hole yeah so the most massive supermassible black holes that are in the cores of the galaxy that sit in the centers of galaxy clusters so like that central CD galaxy in the core of coma in the core of Virgo yeah like the Phoenix the Phoenix black hole there's a ton yeah six one eight or something like that yeah these supermassive black holes that will be even more supermassive in the future they will be the last ones to decay away so we will go from a universe that is is

25:32I don't know the correct word poxed with black holes of stellar mass of intermediate mass of supermassive to just intermediate and supermassive to just supermassive to just the most supermassive yeah and eventually just energy just and and so with this Hawking radiation mostly in the form of photons yeah will will end up again in each one in effectively its own observable universe yeah that there will there we know and they will all be the same temperature that there will just be this giant universe filled with energy for Hawking radiation unable to communicate with any other photon even at the speed of light and as the universe expands those photons get redder and redder right right right and and the thing that's important to understand because we talked about the you know maybe proton sulfate decay maybe they won't but the the thinking right now is that all matter falls under Hawking radiation yeah so not just black holes black holes are these sort of the

26:37extreme end of this but even like neutron stars white dwarfs you me that whatever is this mechanism it probably affects all matter and so with proton decay isn't a thing don't worry just wait Hawking radiation will be a thing and so even the longest lived person in the robot body who's been around for 10 to the power of 100 years will lose their particles one by one to Hawking radiation until nothing survives yeah and in fact probably these things are cool sooner because they they don't have the same kind of gravity well like black holes too so I forget there was this paper that we reported on where they should have gave you the dates when neutron stars will we will we will evaporate when people will evaporate yeah yeah that was the paper that I looked at and I'm like we still don't know protons I decided to just push it over there this is a separate mechanism this is this is this is right you know I understand it's a separate mechanism but I simply took the

27:42I do not wish to to read this theory of paper right now yeah yeah we did that we reported on it it was fun I think even Brian co-reline did it anyway um so now we are 10 to the power of 100 years the universe is nothing but energy empty empty maximum entropy yeah yeah okay all right so you're going to offer one alternate yeah hellhole I guess right no please you know like I hope we get the heat death of the universe but no maybe there's something even more horrifying yeah yeah so well there there's actually an option C which is our universe merges with another universe and physics as we know it someplace ceases to exist but that's a different episode um so in the our universe doesn't have some outside force decides it make it cease to exist given our

28:45universe is allowed to see its natural ending um we're still piecing together how the amount of dark energy in the universe changes with time and if the amount of dark energy is such that the universe keeps accelerating and if that acceleration is accelerating there could come a moment that is actually a strange nightmare I had as a small child I was a very weird child which surprises absolutely no one and for reasons that will never make sense to me someone attempted to explain the expansion of the universe to me when I was like in kindergarten don't do that to kindergarteners and I was honestly afraid that by the time I was an adult expansion would have made it so that the neutrons in my brain couldn't talk to each other anymore don't explain

29:45expansion that's fine it's fine it's fine it's fine just don't explain it to little Pam and else but they'll love it but in the idea of the cosmic rip that weird nightmare I had as a five year old sort of becomes reality because it gets to the point that regular matter is getting torn apart as the universe is expanding faster than other things are tearing things apart and so like our galaxy will still be doing galaxy things and then expansion will start tearing stars off then expansion will start tearing stars apart and then expansion will start tearing atoms apart and that's just horrifying yeah um what and this all depends on whether the rate of dark energy changes over time and for the longest time the answer was it does not right like it really looks

30:46like dark energy has been consistent over time the most modern research is that maybe dark energy does change over time yeah yeah but but weakens and so the what the evidence appears to be leaning towards is that dark energy might be variable but it appears to be lessening over time and so the you know if you asked us this question maybe five years ago we were like I don't know but now we're the point where dark energy is actually being measured quite well there's and we got more coming nanskrystral when veer rubin yeah that combination yeah desi desks so there are there was like five or six different instruments all working to kind of get to the bottom of this question and these scales it's really scale yeah yeah it is amazing uh i think we didn't episode about this anyway um but we are getting to this point the answer is it looks like you know dark energy is either constant or variable and if it's variable seems to be decreasing and if it's decreasing don't worry about the big rep right but it would it would be like me you know 10 billion years from now 15

31:46billion years from now like it's like it's a fraction of the of that current that future age of the of the universe the way i think about it is it's the kind of thing that is unlikely the way my coffee cup simultaneously aligning all of its atoms in such a way that it falls through the desk to the floor uh is unlikely could it happen yes is that a theoretically interesting uh thing to contemplate yes in an infinite universe it would happen inevitably but is it going to happen in my lifetime no and and so is the big rep probably going to happen probably not but you have to consider these realities because we don't have enough data to completely roll them out so so so you're thinking like long enough time sort of the quantum mechanical weirdness rips the universe in half just randomly yeah yeah or makes a new big bang

32:48which is something else that people have been theoretically exploring yeah yeah yeah there was a calculation uh Sean Carroll did this and i forget i forget the number and i apologize but it was like two to the power of a number and then to the power of another number like it was a ludicrously large amount of time but you would just get randomly the raw material for another big bang appearing in a spot in the sky that could begin that process and observable universe anyway not more outside of that quantum fluctuations are funky they're awesome and and if the universe is infinite in time a new universe forming is an is an inevitable outcome of of eternity so there you go hopeful yeah you're gonna end up within just a ludicrous amount of time where you have the heat death of the universe and it's not there's not death by heat it's the death of heat but yeah hopefully if quantum mechanics are right then a new universe will form and and destroy this one

33:52and that in two episodes is the beginning and the end of everything we did it we did it it's excellent we just we just had to skip that messy middle part exactly all right that was wonderful thanks bagel thank you phraser and thank you to all of you out there who are supporting the show uh just as a reminder we are now out free there were no ad bricks in this episode there will be no ads running associated with this episode this is our new future ride or die if you want to help make sure that my heavily beating heart doesn't explode as i worry about paying salaries for alley of viva and rich uh please join us at patreon.estronomycast.com um all episodes are without any paywalls their creative comments licensed we rely on you to make everything we do possible and paying patrons get early access to everything we possibly can. This month we'd like to thank the following patrons for all of their support here at astronomy cast. Buginette

34:58Buri Gowin, Eric Lee, Jeanette Wake, Michael Purcell, Andrew Polestra, David, David Resetter, Gerhard Schweitzer, Jason Kwong, Joe McTee, Sergei Manolev and Segei Kamler. Now if you notice that list is a whole lot shorter than it was last year this is because we have updated our patreon tiers moving around some benefits to reflect the effort it takes our team to do things. Believe it or not reading your names is one of the most stressful things i do because i really struggle with pronouncing things and feel bad when i screw up. We've moved, read your name to the $50 and up tiers meeting with you once a year to the $20 and up tiers adding your name to the end of video is to $10 with lower and higher tiers remaining unchanged. Thank you. You are what makes this show possible all of you in all of the tiers. We did it. We did it. Thanks, fellow.

36:00Thank you. See you next week. We'll bye everyone. Astronomy Cast is a joint product of universe today and the planetary science institute. Astronomy Cast is released under a creative commons attribution license. So love it. Share it and remix it. But please credit it to our hosts, Fraser Kane and Dr. Pamela Gay. You can get more information on today's show topic on our website, astronomycast.com. This episode was brought to you thanks to our generous patrons on Patreon. If you want to help keep this show going, please consider joining our community at patreon.com slash astronomy cast. Not only do you help us pay our producers a fair wage, you will also get special access to content right in your inbox and invites to online events. We are so grateful to all of you who have joined our Patreon community already. Anyways, keep looking up. This has been Astronomy Cast.