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How will the Universe die? · Daniel and Kelly’s Extraordinary Universe

0:04
Speaker 1: You're basically telling me that the universe could end tomorrow, right, Um,
0:10
Speaker 1: it's very unlikely because it didn't end yesterday. Into the
0:15
Speaker 1: possibility that the laws of physics won't change is small. Yes, exactly. Hi,
0:30
Speaker 1: I'm Jorge and I'm Daniel, and this is Daniel and
0:33
Speaker 1: Jorge explain the universe, the entire god forsaken universe and
0:38
Speaker 1: everything in it. That's right, even the parts we can't see,
0:42
Speaker 1: even the parts we will never see. We're going to
0:44
Speaker 1: explain them all to you today on the program The
0:48
Speaker 1: End of the Universe. How will the universe end? Will
0:54
Speaker 1: it end? What's it going to be like? And what
0:57
Speaker 1: should you order in order to prepare? Do we have
0:59
Speaker 1: a spoiler alert at the top of the episode? Well,
1:02
Speaker 1: do you know the fate of the universe. I'm curious
1:04
Speaker 1: to hear. Do you have me at the edge of
1:05
Speaker 1: my seat now, or hey, spoil it for me. I'm
1:07
Speaker 1: desperate to know how will the universe end? Mostly I
1:10
Speaker 1: just have Internet rumors. I think you know some plot
1:14
Speaker 1: points of Leaked Well, you know, the Internet is always right,
1:17
Speaker 1: It's wisdom of the crowd thing, right, So this is
1:23
Speaker 1: an interesting question. So, Daniel, assuming that we survived the
1:27
Speaker 1: next couple of years. Why is this an important question?
1:30
Speaker 1: Why is an important question? Why do we want to
1:32
Speaker 1: know how the universe ends? Well, you had me just
1:34
Speaker 1: a minute ago in the edge of my seat because
1:36
Speaker 1: I thought you were going to tell me the answer.
1:38
Speaker 1: I think it's a it's a basic human curiosity. You know,
1:41
Speaker 1: there's this desire to understand where we came from, why
1:44
Speaker 1: we're here, how this all works, what's the point of existence, basically,
1:48
Speaker 1: what's the context? And I think people want to know
1:51
Speaker 1: how the universe is going to end because it's part
1:53
Speaker 1: of that framing. You know, it's like as interesting as
1:55
Speaker 1: knowing how the universe began, yeah, or like how are
1:59
Speaker 1: you going to die? Yeah, exactly, Or if you're gonna die,
2:01
Speaker 1: if you're gonna get uploaded to the cloud or downloaded
2:04
Speaker 1: into a robot, or I'm actually talking to you from
2:06
Speaker 1: the cloud Tenniel, Well you're talking to a robot. So
2:12
Speaker 1: I think that there's this sort of the large scale
2:15
Speaker 1: human curiosity answer, like you know, what is the answer
2:18
Speaker 1: of life, the universe and everything? And then there's also
2:21
Speaker 1: the short term like are we going to survive the
2:23
Speaker 1: next couple of years? Are our kids going to have
2:25
Speaker 1: a place to live. You know, why do we care
2:27
Speaker 1: about the environment, why do we care about human survival
2:30
Speaker 1: of human society? Because we want to be around. So
2:32
Speaker 1: when you say we, you mean like us as a species. No,
2:37
Speaker 1: I mean we as and me and my direct genetic offspring.
2:40
Speaker 1: And oh I see, I see nobody else matters. You
2:43
Speaker 1: can cut off all of the other parts of the
2:45
Speaker 1: evolutionary tree. Well, this is a deep question, And as usual,
2:50
Speaker 1: we went out and asked people how they thought the
2:53
Speaker 1: universe would end. And here's what people on the street
2:55
Speaker 1: had to say. How do you think the universe is
2:57
Speaker 1: going to end? Um? I've heard a lot of theories
3:01
Speaker 1: about this sudden reaches the end of its life cycle
3:06
Speaker 1: and like I was just combusting in this huge qual
3:08
Speaker 1: of fire the universe. Um, well, there isn't a big
3:13
Speaker 1: bang eventually predicted. It will initial collapse upon itself. I
3:17
Speaker 1: feel like it's going to end up collapsing on itself basically,
3:19
Speaker 1: sort of just like snuffing out the light in a
3:22
Speaker 1: certain way to take everything in using the forest action
3:24
Speaker 1: in order to be able to pull into a different dimension,
3:26
Speaker 1: though we don't know of all. Right, Well, first, I
3:30
Speaker 1: like how people were not very optimistic, Like, nobody said
3:34
Speaker 1: the universe is going to end. I thought it was
3:36
Speaker 1: going to go on forever in this amazing uh state
3:40
Speaker 1: of euphoria. And everyone's like, I don't think we're gonna
3:43
Speaker 1: survive the next ten years, yeah, or we're gonna get
3:45
Speaker 1: swallowed by the sun or something. Everybody had a pretty
3:48
Speaker 1: dark view of the future. But I thought it was fascinating.
3:51
Speaker 1: I had a little bit of trouble getting people to
3:53
Speaker 1: actually answer the question, or maybe to hear the question.
3:56
Speaker 1: Most of the people, have you noticed, answered the question
3:59
Speaker 1: what's going to be the fate of the Earth or humans?
4:01
Speaker 1: If I pushed them, I reminded them I said no, no, no,
4:04
Speaker 1: the whole universe. Then they would maybe think as far
4:07
Speaker 1: as the Solar system. But I think very few people
4:09
Speaker 1: have thought about the universe as a whole coming to
4:12
Speaker 1: an end. Maybe no would even imagines that's a possibility
4:15
Speaker 1: that it would end, or that it would even kind
4:16
Speaker 1: of matter to the human species, right, like, maybe we're
4:20
Speaker 1: just this tiny little blip in the history of the universe. Yeah. Absolutely.
4:25
Speaker 1: I think people are not very confident that the the humanity
4:27
Speaker 1: is gonna last a long time. But I suspect that
4:29
Speaker 1: there's this underlying confidence that the universe is going to
4:32
Speaker 1: be here forever. I mean, think about how big it is,
4:35
Speaker 1: how vast, how much stuff there is, Like, how would
4:37
Speaker 1: you even get rid of it all? You know, if
4:39
Speaker 1: your job, Jorge was to end the universe, that would
4:42
Speaker 1: take a long time, right, going around hoovering up all
4:45
Speaker 1: these stars and planets that have been created and throwing
4:47
Speaker 1: it in a in a trash compact or something otherwise
4:51
Speaker 1: known as a black hole. Yet, well, it's interesting to
4:53
Speaker 1: think about the universe even anything, like you said it, like,
4:56
Speaker 1: it's so vast, it's so huge. What would it even
4:59
Speaker 1: mean for it to end? You know, likes to get
5:02
Speaker 1: thrown out somewhere, Does it explode, does it turn into
5:05
Speaker 1: something else? Like if it turned into something else, isn't
5:08
Speaker 1: it still the universe? That's right? And it's a perfect
5:11
Speaker 1: reflection of the other really deep question, which is how
5:14
Speaker 1: did the universe begin? Right? You ask these questions what
5:17
Speaker 1: would it mean for the universe to end? What would
5:18
Speaker 1: be after that? It's the same as asking what came
5:21
Speaker 1: before the universe started? How did it begin? But we
5:23
Speaker 1: think now the universe did have a beginning, right, it
5:26
Speaker 1: has an age. Right, he started a certain moment fourteen
5:29
Speaker 1: billion years ago, the Big Bang. In the Big Bang,
5:32
Speaker 1: it's actually pretty natural to think that it might also
5:35
Speaker 1: have an end point, right, I mean at a starting point,
5:37
Speaker 1: why not an end point if it could go from
5:40
Speaker 1: nothing to something. Yeah, everything that has the beginning has
5:43
Speaker 1: an end, except for things that haven't ended. But yes, um,
5:48
Speaker 1: such as the universe and this podcast, which is you know,
5:51
Speaker 1: still going on. Do you think it's more natural to
5:53
Speaker 1: think of since the universe we think at a beginning
5:56
Speaker 1: the Big Bang, you think it's natural that it might
5:58
Speaker 1: have an end. It can't just be an open and
6:01
Speaker 1: the thing it could be. But it's also could be
6:03
Speaker 1: something that has a finite life. I mean, it had
6:05
Speaker 1: a specific beginning, so we could also have a specific end,
6:09
Speaker 1: and what happens after that we'll just be could be
6:11
Speaker 1: something else we don't really call the universe because it's
6:13
Speaker 1: so alien and different. The way before the universe began,
6:17
Speaker 1: we think of there being no space and no time.
6:19
Speaker 1: I mean maybe there was something you know, inflatons or
6:22
Speaker 1: pre inflationary matter, whatever, but not anything recognizable, not anything
6:26
Speaker 1: that followed the laws of physics as we know them,
6:28
Speaker 1: or anything that would make any sense to us. I mean,
6:32
Speaker 1: what does it even mean to not have any space
6:34
Speaker 1: or time? Right? Right? Right? And it's also amazing that
6:37
Speaker 1: we can even consider this question, right, Like, we are
6:39
Speaker 1: standing here fourteen billion years after the Big Bang, and
6:44
Speaker 1: possibly the end of the universe is not for another
6:46
Speaker 1: like trillion years, but we like here in this moment
6:48
Speaker 1: in time, can think about can look around us and
6:50
Speaker 1: be like, all right, this is where things are headed. Yeah, yeah,
6:53
Speaker 1: And I love that feeling, like we don't know if
6:56
Speaker 1: we're halfway through the lifetime of the universe, were like
7:00
Speaker 1: one one trillion of the way through the universe. Imagine
7:04
Speaker 1: if we had been if there was life, you know,
7:06
Speaker 1: a hundred thousand years after the universe began in that
7:09
Speaker 1: hot plasma, they would figure, wow, look the universe is
7:12
Speaker 1: pretty old. It's already a hundred thousand years old, right,
7:16
Speaker 1: but you know, so much was left to happen. They
7:18
Speaker 1: didn't even have stars or planets or black holes or
7:20
Speaker 1: anything exciting. Right, Maybe we're still in those first initial blip.
7:24
Speaker 1: That's just the first slice of time, and most of
7:27
Speaker 1: the history of the universe is deep ahead of us.
7:29
Speaker 1: It could go on for ten to the one thousand years,
7:32
Speaker 1: like we could be in the universe's pre pubescent years,
7:35
Speaker 1: like this is the awkward tween years, or it could
7:39
Speaker 1: be the birth Busicists in a trillion years could classify
7:43
Speaker 1: this whole part as the Big Bang. They're like, oh,
7:45
Speaker 1: that was just you know, the first part of the
7:47
Speaker 1: Big Bang, and the second part of the Big Bang,
7:49
Speaker 1: and then the last dregs the Big Bang before we
7:51
Speaker 1: really got started, like this is the Empire strikes back
7:54
Speaker 1: of the Big Bank, the relg So yeah, so we
7:57
Speaker 1: could be like, uh, this could be like just the
8:00
Speaker 1: universe getting started, or it could be like maybe the
8:03
Speaker 1: fading years, like this is this is it like we've plateaued,
8:07
Speaker 1: or it could be like, um, we are under the
8:09
Speaker 1: decline of the universe. So I think we figured it out.
8:11
Speaker 1: We need to know whether the universe will end so
8:14
Speaker 1: that we know whether it should have a midlife crisis, right,
8:16
Speaker 1: and they don't want to miss your midlife crisis, your
8:19
Speaker 1: opportunity to drive fast cars and buy some buy some
8:22
Speaker 1: new galaxies. Maybe those galaxies are way too young for you, Universe.
8:30
Speaker 1: That's disgusting. So we don't know where we are in
8:35
Speaker 1: the lifetime of the universe, like we could be at
8:37
Speaker 1: the youth, or we could be in the middle age
8:39
Speaker 1: of the universe. We don't know. Um, so what what
8:42
Speaker 1: I guess what do we know from looking around us
8:44
Speaker 1: about the lifetime or the age of the universe. Well,
8:47
Speaker 1: basically nothing, but basically nothing. We have no concrete evidence
8:51
Speaker 1: of the universe will ever end. I mean as far
8:54
Speaker 1: as we know. But we were extrapolating from, as you say,
8:58
Speaker 1: a very small amount of information only for teen billion
9:00
Speaker 1: years of history, and now we're trying to extrapolate into
9:02
Speaker 1: billions and trillions and gazillions of years. Right, So, currently
9:07
Speaker 1: we know and if you listen to our podcast episode
9:09
Speaker 1: about dark energy, you know the universe is expanding and
9:13
Speaker 1: that that expansion is accelerating. So things are moving away
9:16
Speaker 1: from each other, and every year that movement happens faster
9:19
Speaker 1: and faster. Things are spreading out right. Yeah, the universe
9:22
Speaker 1: is getting bigger and things are getting more spacious. Yeah,
9:26
Speaker 1: So we have to think carefully about what we mean
9:28
Speaker 1: for the universe to end. For a while, people thought
9:31
Speaker 1: the universe's expansion might stop and slow down, and it
9:34
Speaker 1: might even be that there was enough gravity to pull
9:36
Speaker 1: everything back in to collapse it back into a dot
9:41
Speaker 1: and the sort of the way the universe started. A
9:43
Speaker 1: nice symmetry there. Yeah, the big crunch, Yeah, the big crunch.
9:46
Speaker 1: And in theories where you have a big bang and
9:49
Speaker 1: then expansion and then a big crunch which starts another
9:52
Speaker 1: big bang, you don't think of that big crunch is
9:54
Speaker 1: a big crunch. You call it the big bounce because
9:56
Speaker 1: it's sort of like the universe has these cycles. We
9:58
Speaker 1: have bang and crunch and bang and crunch and sort
10:00
Speaker 1: of more like a bunch of bounces where the universe
10:03
Speaker 1: expands and contracts. It's kind of like when you when
10:05
Speaker 1: you're like hyperventilating and you grab a paper bag and
10:08
Speaker 1: you're like breathing into it and out of it, into
10:10
Speaker 1: it and out of it. That's kind of like the
10:12
Speaker 1: view of the universe, right, like it's expanding and then
10:14
Speaker 1: it collapses compands exactly, and then you get into some
10:18
Speaker 1: semantic distinctions, like if the universe expands and then collapses
10:23
Speaker 1: back down to a singularity or something really small and
10:25
Speaker 1: dense again, is that really the end of the universe
10:28
Speaker 1: and the start of a new universe or is it
10:30
Speaker 1: really just you know, another cycle in the lifetime of universe.
10:33
Speaker 1: In which case the universe could have been going on forever,
10:36
Speaker 1: bouncing and bouncing and bouncing along merrily as we as
10:39
Speaker 1: we live and breathe, you know. Or or it could
10:41
Speaker 1: be that between bounces it could be very different. It's
10:43
Speaker 1: like the same energy would be the same energy, but
10:46
Speaker 1: maybe not the same particles, right, because like when they
10:48
Speaker 1: get compressed at a small they just kind of turned
10:51
Speaker 1: into pure energy, and then then when it expands again,
10:54
Speaker 1: it becomes other particles. Right. Yeah, if you're like naming
10:57
Speaker 1: this electron, then an individual electron name read no longer
11:00
Speaker 1: exists in the next universe. Fred E fred e exactly.
11:06
Speaker 1: And uh, it's anti particle, anti freddy and um, just
11:10
Speaker 1: like pasta and anti pasta. But the energy is of
11:13
Speaker 1: course the same and so and even the rules of
11:16
Speaker 1: physics would probably be the same, So it's not like
11:18
Speaker 1: you get a dramatically different universe. Although you know, the
11:21
Speaker 1: quantum fluctuations in those blobs could give you all sorts
11:24
Speaker 1: of weird things and weird different structure in future universes.
11:28
Speaker 1: So that's one possibility, is that the expansion could turn
11:31
Speaker 1: around and crunch. I have so many questions for you,
11:34
Speaker 1: But before we dive in let's take a short break before.
11:48
Speaker 1: We only need about gravity and scars and matter. And
11:50
Speaker 1: we assumed that gravity, at some point it's just gonna
11:53
Speaker 1: bring everything because if you put a bunch of like, um,
11:56
Speaker 1: those particles out in space, the gravity will pull them together. Right,
12:00
Speaker 1: that's right. Gravity is really weak, but it's got a
12:02
Speaker 1: lot of time, and so eventually it will gather it
12:04
Speaker 1: all together and crunch it down into a planet or
12:07
Speaker 1: an asteroid, or a star or a black hole, depending
12:09
Speaker 1: on how much stuff there is. And that's what people thought.
12:11
Speaker 1: People thought, like all those all the stars and galaxies
12:14
Speaker 1: eventually would slow down and get pulled together into one
12:18
Speaker 1: ginormous black hole thing. Point. Yeah, that was one idea
12:23
Speaker 1: people had. And then you know, we discovered dark energy.
12:25
Speaker 1: We discovered that the universe is expanding faster and faster
12:28
Speaker 1: every year right now. So then for a long time,
12:31
Speaker 1: this idea of a big crunch was crossed off the list,
12:33
Speaker 1: but I think prematurely. Oh you mean, like, so we've
12:37
Speaker 1: we discovered dark energy, meaning that there's some kind of
12:39
Speaker 1: energy permeating the whole universe that's making it expand faster
12:43
Speaker 1: and faster. And so we said, um, it's not going
12:47
Speaker 1: to crunch back in guys like this. Dark energy is
12:50
Speaker 1: a big deal. It's pushing everything further away faster and faster.
12:54
Speaker 1: We're never going to come back together again. Yeah, that
12:56
Speaker 1: was sort of the new prevailing wisdom as about twenty
12:59
Speaker 1: years ago. But I think that's premature because we don't know, Like,
13:04
Speaker 1: we don't know what dark energy is. We don't know
13:06
Speaker 1: how it works. We don't know what it's going to
13:09
Speaker 1: do in the future. We do know that it has
13:11
Speaker 1: some time dependence, like it turned on five billion years ago.
13:14
Speaker 1: Is going to keep going? Is it going to accelerate more?
13:17
Speaker 1: Is it going to stop? I mean to extrapolate from
13:20
Speaker 1: the last few billion years into the next trillion requires
13:23
Speaker 1: a lot of confidence, and we can't do that extrapolation.
13:26
Speaker 1: Like dark energy could flame out or something right or
13:28
Speaker 1: flip flip exactly. It could turn around and make a
13:32
Speaker 1: massive crunch. It might even like bring everything back together
13:35
Speaker 1: or something. Yeah, nobody can predict what it's going to
13:37
Speaker 1: do because we don't understand it at all. We're just
13:39
Speaker 1: watching it happen. Dark energy is the observation that the
13:43
Speaker 1: universe expansion is accelerating recently, but it's not really a
13:47
Speaker 1: solid prediction, what's going to happen. So most of the
13:49
Speaker 1: prevailing wisdom these days about the future universe assumes dark
13:53
Speaker 1: energy is going to continue, but there's no guarantee there,
13:56
Speaker 1: and you know, there could be new things in waiting
13:58
Speaker 1: in the future. For us, dark energy only came around
14:01
Speaker 1: five billion years ago. There could be like a dark
14:04
Speaker 1: error energy that comes on in five more billion years
14:06
Speaker 1: and and it totally drowns out dark energy and dominates it,
14:10
Speaker 1: right our er energy, Oh my god, exactly. And then
14:13
Speaker 1: the sequel that the third part of the trilogy, Darkest Energy,
14:20
Speaker 1: fifty Shades of dark Energy exactly. That's the erotic version
14:23
Speaker 1: of the children. So what are the like, what are
14:30
Speaker 1: the scenarios that side of physicists are considering if dark
14:33
Speaker 1: energy doesn't change. Yeah, so if dark energy doesn't change,
14:37
Speaker 1: then it continues pulling the universe apart, meaning creating new
14:40
Speaker 1: space between us and other galaxies, and doing that faster
14:43
Speaker 1: and faster every year. So this scenario is sometimes called
14:46
Speaker 1: the big Rip because essentially feels like somebody's taking the universe.
14:50
Speaker 1: Something shouldn't anthropomorphize. Something is taking the universe and pushing
14:54
Speaker 1: it apart, ripping it to shreds. Things get farther and
14:57
Speaker 1: farther apart every year, and if you look up in
14:59
Speaker 1: the night sky, things start to disappear because they move
15:03
Speaker 1: outside of our observable horizon, and so things get further
15:06
Speaker 1: and further in space apart. Well, now, is that is
15:09
Speaker 1: that like the same franchise, like The Big Rip, the
15:12
Speaker 1: Big Crunch, the Big Bang? Is it all like copyrighted
15:15
Speaker 1: by physicists? That's right, Yeah, it's all owned by the
15:18
Speaker 1: same agents somewhere in Hollywood who we now have to
15:21
Speaker 1: pay royalties to, um if we want to option this. Yeah, exactly,
15:25
Speaker 1: And there's lots of fascinating scenarios there. You know, if
15:28
Speaker 1: things just continue to spread out, then things get more
15:31
Speaker 1: and more dilute, right, and things um things, because everything
15:35
Speaker 1: gets further and further apart, and then you can just
15:38
Speaker 1: sort of let the laws of physics play out and like,
15:41
Speaker 1: what's going to happen to our galaxy? For example, Well,
15:43
Speaker 1: we know that in a few billion years, our galaxy
15:46
Speaker 1: is probably gonna collide with a nearby galaxy, Andromeda. And
15:50
Speaker 1: that's going to be less dramatic than it sounds, because
15:52
Speaker 1: it's mostly just gonna mean the stars shifting around a
15:54
Speaker 1: little bit, and you know, we might get some new
15:56
Speaker 1: asteroids passing through our solar system. But galaxies are mostly
16:00
Speaker 1: really diffuse, right, They don't when when they hit each other.
16:03
Speaker 1: They don't the stars don't actually collide and smash into
16:06
Speaker 1: each other and create enormous cosmic explosions, but they sort
16:09
Speaker 1: of affect each other, right, Like we might get a
16:12
Speaker 1: giant star flying eros and disrupt their whole orbit. Maybe, yeah, absolutely, Yeah,
16:17
Speaker 1: So it's like if two whirlpools join, if you ever
16:20
Speaker 1: see that happen in a pool, they sort of join,
16:22
Speaker 1: emerge in their combined spin forms one new spinning blob.
16:26
Speaker 1: And so for the individual stars, you know, they might
16:28
Speaker 1: get a little disrupted here and there, and in some
16:30
Speaker 1: cases maybe by a lot in rare circumstances um, but
16:34
Speaker 1: mostly we just form a big combined galaxy. But you know,
16:37
Speaker 1: then fast forward another few zillion years and eventually the
16:40
Speaker 1: stars burn out, right, So at some point we keep
16:43
Speaker 1: fast forwarding, the stars are gonna snuff out, like they're
16:46
Speaker 1: just going to become embers and then eventually just kind
16:48
Speaker 1: of like hot stones and then just rocks, then just rocks. Yeah,
16:52
Speaker 1: and we've already gone through several cycles. I mean, the
16:54
Speaker 1: first stars that were in the universe are no longer around.
16:57
Speaker 1: We can't even see their light. Kidding, several cycles of
17:00
Speaker 1: stars that have already happened. The first stars were all
17:02
Speaker 1: hydrogen and they formed and they burned and they imploded
17:06
Speaker 1: and they exploded, right, and then those materials gathered together
17:09
Speaker 1: make new stars, And that's happened, I'm not sure how
17:12
Speaker 1: many times, several times where several cycles deep, which is
17:15
Speaker 1: why we have such interesting atoms like gold and heavy
17:18
Speaker 1: stuff lying around. Right. We aren't there new stars being
17:21
Speaker 1: formed right now out of hydrogen, none of but none
17:23
Speaker 1: of them are hydrogen stars. There are still new stars
17:26
Speaker 1: being formed, but there's being formed out of a mix
17:28
Speaker 1: of hydrogen and heavier stuff. So like stars one point, Oh,
17:31
Speaker 1: nobody knows what that looks like. Yeah, yeah, I think
17:34
Speaker 1: recently people's found some light they think comes from the
17:37
Speaker 1: first stars, but it's still still very preliminary stuff. Yeah.
17:41
Speaker 1: So the stars get heavier and heavier and eventually run
17:43
Speaker 1: out of stuff that burns, and then the universe goes dark.
17:46
Speaker 1: Right then, it's just like the era of stars is over.
17:50
Speaker 1: And it could be that the era of stars is
17:51
Speaker 1: just like a little blip in the history of the universe,
17:54
Speaker 1: and then it goes on for like another gazillion years
17:57
Speaker 1: before anything interesting. Complete darkness, of complete darkness or other
18:01
Speaker 1: things that bread burn right, aren't aren't like quasars and
18:05
Speaker 1: black holes in those amid radiation and light. Yeah, some
18:08
Speaker 1: of them amid some sort of radiation, but nothing as
18:11
Speaker 1: powerful as stars. So what we're facing is a pretty
18:14
Speaker 1: dark time. You know, this could be like the only
18:17
Speaker 1: bright period in the universe, Yes, exactly. Um. You know,
18:21
Speaker 1: in the way I think about the very early universe,
18:23
Speaker 1: is this hot plasma that only lasted a brief period
18:26
Speaker 1: of time, you know, three or four hundred thousand years,
18:28
Speaker 1: and then it was over. And from the point of
18:30
Speaker 1: view of that hot plasma, the universe now is very
18:32
Speaker 1: dark and quiet and cold. But we could be looking
18:35
Speaker 1: forward to another period which is even darker, even quieter,
18:38
Speaker 1: even colder. Right. It's just these rocks floating around, bumping
18:42
Speaker 1: into each other in the dark. Yeah, and then black
18:44
Speaker 1: holes take over. What it means take over, like things
18:47
Speaker 1: just keep bumping into each other in the dark and
18:49
Speaker 1: forming black holes. Yeah, because eventually gravity coalesces these things together. Um,
18:54
Speaker 1: And you know we're talking about two different forces at
18:56
Speaker 1: the same time. Dark energy is pulling galaxies apart, but again,
19:00
Speaker 1: we think probably gravity has enough power to locally hold
19:04
Speaker 1: a clump of stuff together. It's a dark energy can't
19:07
Speaker 1: rip a black hole apart, for example, or rip a
19:09
Speaker 1: star apart. It has enough energy to push away between things,
19:13
Speaker 1: but probably not to shred those things themselves. So gravitationally
19:16
Speaker 1: bound group of matter will probably survive even the dark
19:19
Speaker 1: energy is pushing it away from things, and it will
19:21
Speaker 1: gather together and form a black hole. But this is
19:24
Speaker 1: still the same fate that we would get if you
19:27
Speaker 1: didn't have dark energy, right, Like, eventually the stars would
19:30
Speaker 1: also go out and things would form into black holes.
19:33
Speaker 1: It's kind of like what happens after that that depends
19:36
Speaker 1: on dark energy. Yeah, that's right. Dark energy just tells you,
19:39
Speaker 1: essentially how closely grouped these things are. We're gonna do
19:42
Speaker 1: this all by ourselves and all the other galaxies are
19:44
Speaker 1: going to be invisibly far away, or are we're gonna
19:47
Speaker 1: be able to watch the same thing happened to Andromeda
19:49
Speaker 1: that's happening to us. That's sort of the question. But yeah,
19:52
Speaker 1: you're right. On a local scale, I think it's going
19:53
Speaker 1: to be the same. One scenario is that, you know,
19:56
Speaker 1: black holes take over and then we have a period
19:58
Speaker 1: of the universe where it's just basically only black holes,
20:00
Speaker 1: only black holes, nothing in between. Yeah, or black holes, um,
20:05
Speaker 1: And that that makes a lot of sense to me.
20:07
Speaker 1: You know, like what happens when gravity pushes stuff together,
20:10
Speaker 1: Eventually it gets dense enough to form black holes. And
20:13
Speaker 1: so give gravity enough time and it'll get that done, right.
20:18
Speaker 1: But the problem is black holes. These black holes are
20:20
Speaker 1: going to eventually evaporate, right, Yeah. Black holes do not
20:24
Speaker 1: last forever. As powerful as they are. At some point
20:28
Speaker 1: they like disappear. Yeah, they evaporate because they have energy
20:31
Speaker 1: to them. And everything that has energy gives off radiation,
20:34
Speaker 1: even black holes. And if you're wondering how can a
20:37
Speaker 1: black hole give off radiation, you know, think about a
20:39
Speaker 1: little particle that's living right at the edge of the
20:42
Speaker 1: event horizon in the black hole. These particles can split
20:45
Speaker 1: into two other particles, you know, sometimes just briefly, and
20:47
Speaker 1: this happens all the time. A photon that's flying through
20:50
Speaker 1: the air in front of you splits into an electron
20:52
Speaker 1: and a positron and then back into a photon. But
20:55
Speaker 1: if that happens right at the edge of the black hole,
20:58
Speaker 1: then um, one of them can get sucked into the
21:00
Speaker 1: black hole and one of them can escape, and that's
21:02
Speaker 1: what's called hawking radiation. So yeah, they can lose energy
21:05
Speaker 1: by radiating these particles one at a time, just at
21:08
Speaker 1: the surface of the event horizon, right, yeah, exactly at
21:11
Speaker 1: the surface of the event horizon. And then things get
21:14
Speaker 1: really uncertain, meaning so if we have these black holes,
21:17
Speaker 1: they they're evaporating at the surface, and so they get
21:19
Speaker 1: smaller and smaller or less massive and less massive. And
21:22
Speaker 1: then but that radiation that gets admitted out, where does
21:25
Speaker 1: that go? Doesn't I keep bouncing around the universe? Yeah,
21:28
Speaker 1: and it can get grabbed up by other black holes
21:30
Speaker 1: or conform new black holes, or you know, do other
21:32
Speaker 1: interesting stuff. Or you know, if black holes have shredded
21:35
Speaker 1: enough matter, then maybe you can start to get enough
21:38
Speaker 1: simple matter around that you can make hydrogen and maybe
21:41
Speaker 1: even make another star to um. This is where things
21:44
Speaker 1: get really speculative because the time we don't understand black
21:47
Speaker 1: holes very well. You know, our understanding black holes is
21:49
Speaker 1: very primitive, and so like speculating about how long they
21:53
Speaker 1: live and what happens to that radiation, how much radiation
21:56
Speaker 1: there is exactly. This is all still very theoretical. Um
22:00
Speaker 1: and so then other theoretical questions start to come in,
22:03
Speaker 1: like how stable is matter itself? You know, One question
22:06
Speaker 1: we don't know the answer to is like how long
22:08
Speaker 1: does a proton live? We don't know. We don't know.
22:11
Speaker 1: We've never seen a proton decay. As far as we know,
22:14
Speaker 1: protons are stable. Like that is, you have a proton
22:17
Speaker 1: floating out in the middle of empty space, it will
22:19
Speaker 1: stay there forever as far as we know. Meaning protons
22:22
Speaker 1: are made out of quarks, and so these like the
22:24
Speaker 1: three quarks inside of a pronon just like never ever
22:28
Speaker 1: split off on their own. We've never seen it happen. Yeah,
22:31
Speaker 1: And so we think that proton lives at least billions
22:35
Speaker 1: of years, but you know, it could be that it's
22:37
Speaker 1: lifetime is only a hundred billion years or five hundred
22:40
Speaker 1: billion years, and then it decays. And so it could
22:43
Speaker 1: be that all the protons in the universe eventually decay
22:46
Speaker 1: and into quarks or smaller particles, yeah, exactly, into quarks
22:50
Speaker 1: or other arrangements. There could be a new arrangement that
22:53
Speaker 1: they decay into something else we haven't seen before. But
22:56
Speaker 1: if everything was in a black hole, uh, and then
22:59
Speaker 1: these holes evaporate from hawking radiation that hawking radiation. Does
23:04
Speaker 1: that include like protons or is it only like, um,
23:08
Speaker 1: you know, like photons and gamma rays and things like that.
23:12
Speaker 1: That's a good question. I'm pretty far outside my air
23:14
Speaker 1: of expertise, but my understanding is that it conclude it
23:17
Speaker 1: can include any kind of particle because black holes are
23:20
Speaker 1: very democratic when it comes to particle physics. They can
23:23
Speaker 1: create any kind of particle because we're talking about the
23:25
Speaker 1: creation of virtual particles, which means it can any kind
23:27
Speaker 1: of particle that can be created would be created, but
23:30
Speaker 1: I think predominantly with the lighter particles because those are
23:33
Speaker 1: those dominated for for these ERTI processes. Well, this is
23:37
Speaker 1: a perfect point to take a break. So now that
23:50
Speaker 1: we went from hot plasma, two stars and planets to
23:54
Speaker 1: rocks floating around in the dark, two black holes. Now
23:58
Speaker 1: all these black holes of evap braded and now we're
24:00
Speaker 1: like in the sea of particles. Yeah, exactly. We're well
24:04
Speaker 1: out of our comfort range here because we're extrapolating our
24:06
Speaker 1: knowledge into the zillion year future, and you know, we
24:09
Speaker 1: don't have enough information to confidently say what happens to
24:12
Speaker 1: a black hole after it's been alive for a zillion years?
24:15
Speaker 1: Or how long does a proton survive and can't really
24:17
Speaker 1: decay into something else? And so we really don't know, um,
24:21
Speaker 1: And that's a really fascinating question, is how long can
24:24
Speaker 1: we apply the laws of physics for like are they stable?
24:28
Speaker 1: You know? Do they are they the same forever? We
24:31
Speaker 1: think they've been the same for the last few billion years,
24:33
Speaker 1: but it could be that they change on the time
24:36
Speaker 1: scale of a trillion years and we just haven't noticed.
24:38
Speaker 1: So even like the rules of the game you're saying,
24:41
Speaker 1: could change exactly. And there's one really fascinating, slightly scary
24:45
Speaker 1: scenario that I love that people thought about a lot
24:48
Speaker 1: since the discovery of the Higgs boson, and that's that
24:51
Speaker 1: all the rules of physics could change, and they could
24:53
Speaker 1: change kind of suddenly. What do you mean, like the
24:56
Speaker 1: rules that tell you how things are might suddenly change
25:01
Speaker 1: for everywhere in the universe at the same time. It
25:04
Speaker 1: wouldn't be all everywhere at the same time, but it
25:05
Speaker 1: could happen all of a sudden in one moment and
25:08
Speaker 1: then spread. So let me tell you how that might happen.
25:10
Speaker 1: Um the way the Higgs boson works, it gives mass
25:13
Speaker 1: to other particles, and it does so by feeling the
25:16
Speaker 1: whole universe with this thing called the Higgs field. And
25:19
Speaker 1: if you want to know more about that, listen to
25:20
Speaker 1: our episode on the Higgs field. But the basic idea
25:23
Speaker 1: is that the Higgs field has energy even an empty space,
25:26
Speaker 1: right there's nothing there in it, no matter or nothing
25:29
Speaker 1: happening in a in a cube of space, but there's
25:31
Speaker 1: still the Higgs field there has non zero energy, and
25:35
Speaker 1: that's what gives things mass interacting with this this field
25:38
Speaker 1: that has non zero energy even when it's empty. Okay,
25:41
Speaker 1: But what we don't know is that field itself stable?
25:45
Speaker 1: Like is it stuck in some local minimum, you know?
25:48
Speaker 1: Is it like caught on a ledge somewhere and it
25:50
Speaker 1: just got stuck and it's going to roll out and
25:53
Speaker 1: find a more comfortable, relaxed configuration where it has zero energy.
25:57
Speaker 1: Is that temporary that it has this amount of energy
26:00
Speaker 1: stuck into it, or is it permanent? And there are
26:02
Speaker 1: a lot of theories and particle physics that suggests that
26:05
Speaker 1: it might be temporary, And then it might also be
26:07
Speaker 1: kind of fragile, and then if it's the right thing happens,
26:11
Speaker 1: you could shatter that field or disturb it and perturb
26:14
Speaker 1: it and break it, and so that it could collapse,
26:17
Speaker 1: and that collapse could spread very rapidly. Oh my god.
26:21
Speaker 1: And not that I'm saying that the large hage On
26:22
Speaker 1: collider is going to destroy the whole universe. I'm not
26:25
Speaker 1: saying that, people, I'm very definitely not saying that. But
26:30
Speaker 1: but there are some physics theories in which the Higgs vacuum,
26:34
Speaker 1: this lowest energy state, is not stable and it could
26:38
Speaker 1: collapse into a true vacuum, which would mean there's no
26:41
Speaker 1: Higgs field, which means no particles have mass, which means
26:44
Speaker 1: everything changes. Right, The very laws of physics would be
26:48
Speaker 1: totally different if the Higgs field was different, and the
26:50
Speaker 1: universe as we know it would like suddenly like turning
26:53
Speaker 1: into something else. Turn into something else. Yeah, I mean
26:56
Speaker 1: all of chemistry relies on the structure of the periodic table,
26:59
Speaker 1: which lies on the masses of the particles that make
27:02
Speaker 1: up the atoms, and that would all be different. And
27:04
Speaker 1: the new universe within with the zero Higgs vacuum would
27:07
Speaker 1: also probably be fascinating and beautiful. And interesting, but it
27:10
Speaker 1: would be very different, and you know, your maserati would
27:13
Speaker 1: no longer work, and your bank account would no longer
27:16
Speaker 1: be relevant. We wouldn't work, exactly, We would not work.
27:19
Speaker 1: But you're saying I feel like you're saying, like, hey,
27:22
Speaker 1: don't worry about us. We're just doing physics here. We're
27:24
Speaker 1: not going to blow things up. But well, you know
27:29
Speaker 1: you can always say that, or hey, you're just cartooning
27:31
Speaker 1: in your garage, right, You're not intending to destroy the
27:34
Speaker 1: universe with your cartoons. But but I might draw something
27:37
Speaker 1: of such incredible beauty. Yes, it will collapsed the laws
27:44
Speaker 1: of physics. You know, these theories about how the Higgs
27:47
Speaker 1: vacuum might be unstable. These are just ideas people have
27:50
Speaker 1: and it's fun to think about, and people write papers
27:52
Speaker 1: about how they might end the universe to be dramatic. Um,
27:55
Speaker 1: But I don't think anybody's serious. I'm certainly not worried
27:58
Speaker 1: at all that any cticle physics experiment is going to
28:01
Speaker 1: destroy the Higgs vacuum and change the universe, right right,
28:04
Speaker 1: keep sending those checks exactly so everything next week to
28:09
Speaker 1: download another podcast exactly. Well. It is sort of kind
28:14
Speaker 1: of like knowing when you're going to die, Right, Like,
28:17
Speaker 1: if you knew you were going to die in a week,
28:19
Speaker 1: you would live your life totally different, as opposed to
28:22
Speaker 1: if you knew you were going to live till you're
28:23
Speaker 1: a hundred and twenty, calmly, peacefully in bed, surrounded by
28:27
Speaker 1: your loved ones, you would change the way you make
28:30
Speaker 1: decisions every day. Right, That's right, And I think that's
28:33
Speaker 1: what's reflecting in people's answers to our on the street
28:35
Speaker 1: interviews that they were thinking more immediately, what is the
28:38
Speaker 1: future of the human race, what's the future of my family?
28:40
Speaker 1: How is this all going to affect us? Right? And
28:43
Speaker 1: it is totally possible that, like my jeans, what makes
28:46
Speaker 1: me who I am now? That might live on in
28:49
Speaker 1: my kids, my ancestors, and trillions of years from now,
28:53
Speaker 1: there could be a little piece of me like looking
28:56
Speaker 1: out at the sky and and being like, why is
28:59
Speaker 1: it so dark? That's right, it's possible the humans live
29:02
Speaker 1: for a trillion years. It's absolutely possible, And so we
29:06
Speaker 1: should be concerned about the fate of the universe, not
29:08
Speaker 1: just because we're curious about how the story ends and
29:11
Speaker 1: it's fascinating from a scientific point of view, but yeah,
29:14
Speaker 1: because it could be our home for the next trillion
29:16
Speaker 1: or two trillion years. Yea, if things go well, if
29:20
Speaker 1: people listen to this podcast, that I put your minds
29:23
Speaker 1: at ease or today unsettle you a little bit, a
29:26
Speaker 1: little bit. I mean I thought that this was far
29:28
Speaker 1: way into the future and I wouldn't have to worry
29:30
Speaker 1: about it. But now like the universe could end tomorrow. Yeah,
29:33
Speaker 1: so you know, organize your finances and get your stuff
29:35
Speaker 1: in order, and it's a good idea anyway, appreciate the
29:38
Speaker 1: bright period of the universe. That's right, Yes, this early, beautiful, glamorous,
29:43
Speaker 1: star lit, starfield period of the universe. Yeah, all right,
29:47
Speaker 1: thank you very much for joining us. This has been
29:49
Speaker 1: Daniel and Jorge explained the universe and its end. If
29:59
Speaker 1: you still have a question after listening to all these explanations,
30:02
Speaker 1: please drop us a line. We'd love to hear from you.
30:05
Speaker 1: You can find us at Facebook, Twitter, and Instagram at
30:08
Speaker 1: Daniel and Jorge that's one word, or email us at
30:12
Speaker 1: Feedback at Daniel and Jorge dot com.