Latest / Daniel and Kelly’s Extraordinary Universe / What's the Oldest Thing in the Universe?

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What's the Oldest Thing in the Universe? · Daniel and Kelly’s Extraordinary Universe

0:08
Speaker 1: Hey, Jorge, who is the oldest person you know? I
0:12
Speaker 1: have a couple of uncles that are in their late eighties.
0:16
Speaker 1: I think that's about as old as it gets in
0:18
Speaker 1: my family. That's pretty good. They must have eaten a
0:20
Speaker 1: lot of bananas or zero bananas, whichever is best. I
0:23
Speaker 1: can't keep trying. May either been at a neutral What
0:26
Speaker 1: about you? My grandmother, my mom's mom is a hundred
0:30
Speaker 1: and five years old and she still beats me at scrabble. Wow,
0:33
Speaker 1: what's her secret? I think she just likes beating people
0:36
Speaker 1: at scrabble, and that's what keeps her alive. I guess
0:39
Speaker 1: what age comes wisdom and a very large vocabulary. Hi
0:58
Speaker 1: am orgem a cartoonists and the creator of PhD Comics. Hi.
1:02
Speaker 1: I'm Daniel. I'm a particle physicist and my kids think
1:05
Speaker 1: I'm pretty old, but I feel young at heart. Welcome
1:08
Speaker 1: to our podcast, Daniel and Jorge Explain the Universe, a
1:10
Speaker 1: production of I Heart Radio in which we talk about
1:13
Speaker 1: all the amazing things in the universe, the new stuff,
1:16
Speaker 1: the old stuff, the close stuff, the far away stuff.
1:18
Speaker 1: We talk about everything you want to hear about. We
1:22
Speaker 1: break it down, we explain it to you in a
1:24
Speaker 1: way that we hope also makes you laugh. It's right,
1:26
Speaker 1: we talk about the boring stuff in the universe, but
1:29
Speaker 1: we also like to talk about the extreme stuff in
1:31
Speaker 1: the universe, the things that are pushing the boundaries of
1:34
Speaker 1: what is possible in this crazy cosmos. That's right because
1:37
Speaker 1: the extremes tell us about what the rules are. How
1:40
Speaker 1: hot can something possibly get, how cold can something be,
1:44
Speaker 1: how fast can it's been? What is the brightest possible thing?
1:47
Speaker 1: Because usually when we look at the extremes is when
1:49
Speaker 1: we learned about something new in the universe, we say, wow,
1:53
Speaker 1: we didn't realize it was possible to shoot particles at
1:55
Speaker 1: that high energy the Earth. What could be doing that?
1:58
Speaker 1: So that's why it's a lot of fun to look
2:00
Speaker 1: at the most extreme stuff in the universe. And so
2:02
Speaker 1: we have a series of episodes dealing with the most
2:06
Speaker 1: of a lot of things in the universe. If you
2:08
Speaker 1: look back to our archive, you can listen to episodes
2:11
Speaker 1: about the biggest thing in the universe, the brightest things
2:14
Speaker 1: in the universe, the darkest things in the universe. And
2:17
Speaker 1: so today we'll have an episode about one such extremes.
2:20
Speaker 1: Are are are we giving out awards? Should we be like
2:22
Speaker 1: making trophies and handing them out to astrophysical objects, and
2:26
Speaker 1: we we can send them as certificate, like an email certificate.
2:31
Speaker 1: Maybe just being the subject of a whole podcast episode
2:34
Speaker 1: is enough reward for them. Yeah, they can listen under CV,
2:36
Speaker 1: or they can put a little like logo next to
2:38
Speaker 1: their cover or something that says they were featured in
2:41
Speaker 1: our podcast. That's right. I'm sure the supercluster we're in
2:45
Speaker 1: is always emailing at CV around the universe. And by
2:48
Speaker 1: the way, did you know I was the subject of
2:49
Speaker 1: a podcast? What do you think the email addresses everywhere
2:55
Speaker 1: everywhere at everything dot com. That's right. But even if
3:00
Speaker 1: nobody is interested in winning these prizes, we are interested
3:03
Speaker 1: in exploring them and talking about them because they're super fun.
3:06
Speaker 1: Not only because it teaches us something about the universe,
3:09
Speaker 1: but because these are the wow factors. These are the
3:11
Speaker 1: reasons why the universe is amazing, because things are super
3:15
Speaker 1: big and super hot and super fast and super spinny
3:19
Speaker 1: and super everything. And so today on the program, we'll
3:21
Speaker 1: be asking the question, what is the oldest thing in
3:30
Speaker 1: the universe? The oldest thing, not the oldest person. We
3:35
Speaker 1: already determined that's her grandmother. No, she's she's like twenty
3:39
Speaker 1: something years away from being the oldest person. The oldest
3:41
Speaker 1: person is like almost a hundred and thirty. It's ridiculous.
3:44
Speaker 1: For real, Yeah, for real, Yeah, I think it was
3:47
Speaker 1: like some old French lady. Don't you remember? There was
3:49
Speaker 1: a guy when she was in her eighties. He bought
3:53
Speaker 1: her apartment for some really low price under the deal
3:55
Speaker 1: that she could live in it until she died. He
3:58
Speaker 1: figured she was going to expire in a few years,
4:00
Speaker 1: but then she outlived him, and she lived to one
4:02
Speaker 1: twenty something and he died in his eighties, never having
4:05
Speaker 1: moved into the apartment that he purchased. It's amazing. I'd
4:09
Speaker 1: love to see that person plays grapple with your grandmother.
4:12
Speaker 1: What do you think would win? I don't know. I
4:14
Speaker 1: think there'd be a lot of cheating. I guess who's
4:17
Speaker 1: going to call them out right? Exactly exactly. But I
4:22
Speaker 1: think this is a really fun question because it makes
4:24
Speaker 1: you think about the early days of the universe and
4:27
Speaker 1: like what God formed first and then what's still around.
4:31
Speaker 1: And it's also makes you understand like the grand sweep
4:34
Speaker 1: of time. You know, a hundred deers seems like a
4:37
Speaker 1: long time for us humans. But it's the blink of
4:40
Speaker 1: an eye. Cosmologically, our universe has been around for billions
4:43
Speaker 1: of years, and so it's it's fun to think about
4:45
Speaker 1: those things that just exist on a completely different scale.
4:49
Speaker 1: And I guess we need to get a little bit
4:51
Speaker 1: philosophical here, because you know, this sort of opens up
4:54
Speaker 1: a couple of questions. First of all, what do you
4:56
Speaker 1: mean by the oldest thing in the universe? And I
4:59
Speaker 1: guess do you mean the oldest surviving thing in the universe.
5:01
Speaker 1: You know, there's a whole branch of philosophy, you know,
5:03
Speaker 1: thing is um what is a thing? What defines a thing?
5:06
Speaker 1: What isn't the thing? What makes something two things? Is
5:09
Speaker 1: that a thing? Really? In philosophy? No, I just made
5:12
Speaker 1: that up. We just founded a whole new branch of
5:14
Speaker 1: philosophy right here on the podcast. It's the newest thing
5:18
Speaker 1: in the universe, the latest thing. We should put a
5:22
Speaker 1: sticker in ourselves saying, I philosophies. Yeah, it is an
5:27
Speaker 1: interesting question. What do you call a thing? You have
5:30
Speaker 1: to go through several categories and talk about what is
5:32
Speaker 1: the oldest for various answers of the question what do
5:35
Speaker 1: you mean by a thing? All? Right, well as usual,
5:39
Speaker 1: we were wondering how many people out there thought they
5:42
Speaker 1: knew what is the oldest thing in the universe? So
5:45
Speaker 1: I solicited volunteers to answer questions without doing any research,
5:49
Speaker 1: off the top of your head, answer a hard physics
5:52
Speaker 1: question from a dude on the Internet, and of course
5:55
Speaker 1: people were happy to oblige. So thank you to everybody
5:57
Speaker 1: who participated, And if you would like to answer random
6:01
Speaker 1: future physics questions, please write to me at questions at
6:04
Speaker 1: Daniel and Jorge dot com. Before you listen to these answers,
6:08
Speaker 1: think about it for a second. If someone ask you
6:10
Speaker 1: what is the oldest thing in the universe, what would
6:13
Speaker 1: you answer. Here's what people had to say. Maybe as
6:17
Speaker 1: some proton it is a fortune thing. The oldest thing
6:23
Speaker 1: in the universe, from what I understanding, would be the
6:26
Speaker 1: leftover resident cosmic microwave radiation after the initial Big Bang.
6:33
Speaker 1: But if you're looking for an actual object or a thing,
6:36
Speaker 1: I believe primordial black holes, I'm thinking cosmic background radiation.
6:43
Speaker 1: I think the oldest thing in the universe um is CMD.
6:47
Speaker 1: That's what we can observe at least after that. I
6:52
Speaker 1: think it is cluster of Alexi cluster, which is about
6:57
Speaker 1: twelve and a half million years old. I'm gonna go
7:00
Speaker 1: with space. How about that? Wow, tough question. Maybe black holes.
7:07
Speaker 1: So I would say the oldest thing in the universe
7:09
Speaker 1: would be quirks. But if you mean by something that
7:12
Speaker 1: actually gets assembled, then I would say hydrogen. If you
7:15
Speaker 1: don't mean an object, then I would say a primordial
7:19
Speaker 1: black hole. I'm not entirely sure what the oldest thing
7:22
Speaker 1: in the universe is. I know that after the Big
7:25
Speaker 1: bag Um, as far as we know, that was just
7:29
Speaker 1: plasma and quantum fluctuations. There weren't particles at that point um.
7:36
Speaker 1: These quantum fluctuations we think may have caused primordial black holes.
7:41
Speaker 1: So perhaps that's the oldest thing in the universe. Man,
7:43
Speaker 1: there are some good answers there. Huh yeah, Wow, it's
7:46
Speaker 1: been impressed. Some of these made me think, like, a
7:49
Speaker 1: proton is a protonon of thing? I'm like, huh is
7:52
Speaker 1: it a thing? If you asked the protein, it would
7:54
Speaker 1: say it's definitely a thing, or it's like space. Somebody
7:56
Speaker 1: said space like a space the thing? And could that
7:59
Speaker 1: be all their than anything else. Yeah, that's a really
8:01
Speaker 1: good question because you might then think, well, is the
8:04
Speaker 1: universe a thing? Right, what's the oldest thing in the universe.
8:06
Speaker 1: It's the universe Boom podcast over everything whatever, everything is
8:13
Speaker 1: that that was there from the beginning of everything. Yeah,
8:15
Speaker 1: and you might say everything is definitely a thing because
8:17
Speaker 1: it has the word thing in it, But then nothing
8:20
Speaker 1: is not a thing and it has the word thing
8:22
Speaker 1: in it. So now I'm overthinking it or overthinking it.
8:25
Speaker 1: I think you're trying to win a scrabble here. It
8:28
Speaker 1: sounds like trying to argue what a word is. But yeah,
8:32
Speaker 1: it's it's it's interesting to think about what is the
8:34
Speaker 1: oldest thing because there is sort of an age to
8:38
Speaker 1: the universe. That's right. When we look out to the universe,
8:41
Speaker 1: we see that everything is rushing away from us, that
8:43
Speaker 1: the universe is getting less and less dense. It's spreading out,
8:47
Speaker 1: and when you run the clock backwards, everything compresses and
8:49
Speaker 1: get back to some like original really high dense point.
8:53
Speaker 1: And we have an age for that. We can project
8:55
Speaker 1: that backwards in time, and it's about fourteen billion years
8:58
Speaker 1: ago when everything was really hot and dense. Of course,
9:02
Speaker 1: we don't really know what happens then our theories breakdown
9:05
Speaker 1: at that moment. We don't know if there was a
9:06
Speaker 1: singularity or something came before it or whatever. But that's
9:10
Speaker 1: generally considered roughly to be the approximate age of the
9:12
Speaker 1: whole universe just under fourteen billion years, fourteen billion years young,
9:19
Speaker 1: and you could be fourteen billion years young. This could
9:21
Speaker 1: be like the first moments of the universe on the
9:24
Speaker 1: trillions or quadrillion years life cycle of the universe. Right,
9:28
Speaker 1: we don't know how far down the road we've walked.
9:31
Speaker 1: It seems like a long time, but then again, after
9:33
Speaker 1: ten million years it might have seemed like a long time.
9:37
Speaker 1: And we know now that that's only just the first blip,
9:39
Speaker 1: So we don't really know if we're like looking at
9:41
Speaker 1: most of the iceberg or just the tip of it. Right,
9:43
Speaker 1: it's like a teenager. They feel like they've lived a
9:46
Speaker 1: whole life and everything there's to know about everything. Everything
9:50
Speaker 1: the universe knows nothing man, wait till it grows up.
9:53
Speaker 1: But yeah, how sure are we that's the age of
9:55
Speaker 1: the universe? I know we can we get it from,
9:57
Speaker 1: you know, rewinding the trajectory of space and the expansion
10:01
Speaker 1: of the universe, But is there any ambiguity about that? Like,
10:05
Speaker 1: how sure we couldn't be that the universe didn't do
10:08
Speaker 1: what we think it did, you know what I mean, like,
10:11
Speaker 1: maybe it didn't compress smoothly from what we've see right now, Well,
10:15
Speaker 1: we can see pretty well back in the history of
10:17
Speaker 1: the universe. We don't just project, we can actually see
10:20
Speaker 1: the history of the universe as we look out into space.
10:23
Speaker 1: Remember that it takes light a long time to get
10:26
Speaker 1: here from other places, so things that happened a long
10:29
Speaker 1: time ago really far away, that light is just now
10:32
Speaker 1: arriving at Earth. So we can literally see the history
10:35
Speaker 1: of the universe and we can record its expansion, and
10:38
Speaker 1: so we're pretty sure about the history of the expansion
10:41
Speaker 1: of the universe. What we're not sure about is what
10:43
Speaker 1: that represents. That moment fourteen billion years ago. Was it
10:47
Speaker 1: really a beginning? Was it just like the start of
10:49
Speaker 1: cycle number four and fifty two? Is there an infinite
10:52
Speaker 1: number of cycles before that? Did the universe space assemble
10:56
Speaker 1: from something else, some deeper quantum foam. We don't really
10:59
Speaker 1: understand and whether we can call that a beginning, But
11:02
Speaker 1: we know there was a special moment about fourteen billion
11:04
Speaker 1: years ago. And how certain are we We haven't nailed
11:08
Speaker 1: down to within about a hundred million years. Wow, that
11:11
Speaker 1: is very specific. It's pretty specific, but it's also a
11:14
Speaker 1: big range. You know, like if somebody said to you, hey,
11:16
Speaker 1: I'll meet you tomorrow at three pm plus or mind
11:19
Speaker 1: is a hundred million years, that wouldn't feel very specific,
11:21
Speaker 1: but that would be hard to sing happy birthday about.
11:24
Speaker 1: But if someone said, you know, you're a hundred years
11:26
Speaker 1: old plus or mine is a couple of days, Yeah, yeah,
11:28
Speaker 1: that's true. But I guess my question is how far
11:30
Speaker 1: back can we see, Like can we actually see things
11:35
Speaker 1: back that long? Or is this is it all sort
11:37
Speaker 1: of based on a projection? Now we can see that
11:39
Speaker 1: far back in time. If you look at stuff near
11:42
Speaker 1: our galaxy, you know, we're in the Milky Way, and
11:44
Speaker 1: the neighboring galaxy, Andromeda, is like millions of light years away.
11:48
Speaker 1: So when you're looking at Andromeda, you're seeing what happened,
11:51
Speaker 1: what it looked like millions of years ago. That's the
11:54
Speaker 1: closest galaxy, that's like our immediate neighbor, and that's millions
11:58
Speaker 1: of light years away. Then if you look further out,
12:00
Speaker 1: like billions of light years, you get to these big structures.
12:04
Speaker 1: Because galaxies form themselves into superclusters, and those superclusters are
12:08
Speaker 1: organized into sheets that encompass these vast voids, these bubbles,
12:13
Speaker 1: and one of them, for example, is called the Sloane
12:15
Speaker 1: Great Wall, one of the first of these really big
12:18
Speaker 1: structures to be discovered, and it's about a billion light
12:21
Speaker 1: years away. A great wall of stars or galaxies, a
12:24
Speaker 1: great wall of galaxy superclusters, right, So stars are formed
12:28
Speaker 1: into galaxies, galaxies are formed into clusters, Galaxy clusters are
12:32
Speaker 1: formed into superclusters, and then those are organized into these walls,
12:36
Speaker 1: these sheets that wrap around these bubbles. I wonder who
12:39
Speaker 1: paid for that, Danny. It's a lot of dry wall
12:43
Speaker 1: and a lot of paint. Who picked those colors? Right?
12:45
Speaker 1: With their galactic arguments about which shade of green or
12:48
Speaker 1: which shade of red to burn, which spectrum of the
12:51
Speaker 1: electromagnetic radiation it's going to give off, So that that's
12:54
Speaker 1: a billion light years away. That's billion light years away,
12:57
Speaker 1: and then we can look further out, and it becomes
12:59
Speaker 1: hard earned harder to look further out because these things
13:02
Speaker 1: are more distant, and so you need more powerful telescopes,
13:05
Speaker 1: or you need to focus those telescopes for a longer time.
13:08
Speaker 1: And that's like the reason we don't have a great
13:10
Speaker 1: map of the entire universe so far is just that
13:13
Speaker 1: that light is distant and dim, and so you need
13:16
Speaker 1: a lot of telescopes looking at it. But we do
13:18
Speaker 1: see some individual galaxies, like the hubble points itself in
13:22
Speaker 1: one direction of space and just sort of like accumulates
13:25
Speaker 1: photons for days and days and days. Then you can
13:28
Speaker 1: see the dimmest galaxies, the ones where photons are arriving
13:31
Speaker 1: most rarely because they've spread out through the whole universe.
13:35
Speaker 1: And there we can see galaxies that are like more
13:37
Speaker 1: than thirteen billion light years away. Wow, that's almost the
13:41
Speaker 1: age of the universe. It's almost the age of the universe,
13:43
Speaker 1: which means something amazing and fascinating, right. It means that
13:46
Speaker 1: galaxies formed very early on in the universe. For example,
13:50
Speaker 1: the oldest known galaxy is one called g n Z eleven.
13:55
Speaker 1: It's thirteen point four billion light years away. That means
13:59
Speaker 1: that it's formed just a few hundred million years after
14:02
Speaker 1: the start of the whole universe. Well, and the images
14:04
Speaker 1: we're seeing of that galaxy, it looks like it did
14:09
Speaker 1: thirteen billion years ago, right, Yes, we're seeing baby pictures
14:13
Speaker 1: of that galaxy, Like we don't know what's going on
14:15
Speaker 1: with that galaxy today. Does it even still exist, did
14:19
Speaker 1: it leave home, did it get a job, did it
14:20
Speaker 1: have a big argument with his parents? We don't know,
14:23
Speaker 1: But the baby pictures are what are arriving now at Earth.
14:26
Speaker 1: And if we waited another ten billion years or so,
14:29
Speaker 1: we would see the future of that galaxy, what happened
14:32
Speaker 1: to it, and everything that subsequently occurred. But right now
14:35
Speaker 1: we're only seeing the original light that left thirteen billion
14:38
Speaker 1: years and when it was and it looks like a
14:39
Speaker 1: fully formed galaxy, like you can see the structure in it.
14:43
Speaker 1: And even though it's that young, what I mean is
14:45
Speaker 1: it doesn't look lumpy and wrinkled like a baby. It
14:47
Speaker 1: doesn't look lumpy and wrinkled like galaxy in the very
14:50
Speaker 1: early universe do look different than galaxies today. A lot
14:53
Speaker 1: of galaxies we have today are really big because they're
14:55
Speaker 1: the product of galaxy mergers. Many galaxies come together in
14:59
Speaker 1: a lot out of the spiral galaxies are the product
15:02
Speaker 1: of the mergers of several galaxies. So this looks like
15:05
Speaker 1: a younger galaxy and it's a great way to study
15:07
Speaker 1: the very early universe. Like these infrared telescopes that we
15:11
Speaker 1: have and that we're sending up soon are going to
15:13
Speaker 1: be great at looking at this light from the really
15:15
Speaker 1: really oldest galaxies, the ones that don't glow as much. So, yeah,
15:19
Speaker 1: we can use this to study galaxies at the very
15:21
Speaker 1: early age. And they do look a little different, like
15:23
Speaker 1: galaxies looked different in the very beginning of the universe
15:26
Speaker 1: than they do today. You see. I guess the question is,
15:28
Speaker 1: and have we seen any stars that old or I
15:31
Speaker 1: guess I mean, if you look at the galaxy, you're
15:33
Speaker 1: looking at the stars in it, so you're sort of
15:35
Speaker 1: looking at really old stars too. Yeah, we are looking
15:38
Speaker 1: at old stars. But there's sort of three populations of stars.
15:42
Speaker 1: There's the stars that are around today, and most of
15:45
Speaker 1: these have formed from the collapse of the previous generation
15:49
Speaker 1: of stars, and those stars formed from the collapse of
15:52
Speaker 1: the previous generation of stars. Remember, stars happen when you
15:56
Speaker 1: have a bunch of gas and stuff gathered together by
15:58
Speaker 1: gravity enough so that they burn. And we think that
16:01
Speaker 1: the first generation of stars formed fairly early in the universe,
16:04
Speaker 1: but they were really big, and really big stars burn
16:07
Speaker 1: really really hot, and so they don't last for very long.
16:10
Speaker 1: And so that population of stars we haven't ever seen.
16:13
Speaker 1: We haven't seen any stars from that time. But if
16:16
Speaker 1: we're seeing a galaxy from that time, aren't we seeing
16:19
Speaker 1: the stars from that time too, Or are you saying
16:22
Speaker 1: we haven't seen like an individual pinpoint of light that
16:25
Speaker 1: is one of the oldest stars. We haven't seen an
16:27
Speaker 1: individual pin point of light. But also we think that
16:29
Speaker 1: this galaxy has stars from the second population. We think
16:32
Speaker 1: that first population didn't live long enough in this galaxy.
16:37
Speaker 1: It lived less than a billion years, less than a
16:39
Speaker 1: billion years. Those stars did not last for a billion years.
16:42
Speaker 1: They were really big and hot and burned very quickly,
16:45
Speaker 1: so we haven't seen any direct evidence of those stars yet.
16:48
Speaker 1: Those are called population three stars. Wow, they burned out
16:51
Speaker 1: in less than a billion years, less than a billion years,
16:54
Speaker 1: absolutely just out of hydrogen, just out of hygen and
16:57
Speaker 1: the keys that they're really big and really big stars
17:00
Speaker 1: burned really hot and really fast, and so those are
17:02
Speaker 1: all gone. And that's an interesting point because those stars
17:05
Speaker 1: were created a long time ago, but they're no longer around.
17:09
Speaker 1: So they were created in the early universe, but they
17:11
Speaker 1: don't exist anymore, so they're not really old because they're gone.
17:15
Speaker 1: I see. So galaxy g n Z eleven is thirteen
17:18
Speaker 1: point four billion light years away, which means it's thirteen
17:22
Speaker 1: point four billion years old. So is that the oldest
17:25
Speaker 1: thing in the universe? We don't know if it's thirteen
17:27
Speaker 1: point four billion years old. We know it existed thirteen
17:30
Speaker 1: point four billion years ago, we don't know what it's
17:33
Speaker 1: doing today. Right. It's like if you look at a
17:35
Speaker 1: baby picture from somebody from a hundred years ago, you
17:38
Speaker 1: don't know if they lived till two or five or
17:40
Speaker 1: a hundred. So they could be the oldest person alive
17:43
Speaker 1: if they were still around today, but you don't know,
17:45
Speaker 1: you're just looking at the baby picture. I see a
17:48
Speaker 1: lot of people when they think about, you know, what
17:50
Speaker 1: is the oldest thing in the universe, they are tempted
17:52
Speaker 1: to think really far away, really distant in time. But
17:56
Speaker 1: we don't know if those things are still around. I see,
17:58
Speaker 1: we're asking what's the oldest thing that is still around? Yeah,
18:01
Speaker 1: because you're not old if you didn't live very long. Right,
18:03
Speaker 1: somebody was born two hundred years ago and died ten
18:06
Speaker 1: minutes later, isn't the oldest person in the world? Right? Oh? Interesting,
18:10
Speaker 1: I guess I guess what would happen? What could have happened?
18:13
Speaker 1: To that galaxy. Like galaxies just don't disappear. Galaxies don't disappear,
18:19
Speaker 1: that's true. They get absorbed into other galaxies sometimes or
18:22
Speaker 1: they get torn apart by other galaxies that come near them.
18:26
Speaker 1: You know, there can be a lot of gravitational turbulence,
18:28
Speaker 1: so that galaxy may not exist on its own anymore
18:31
Speaker 1: and may have been absorbed by collisions into other galaxies,
18:34
Speaker 1: or it could have gone shredded, yeah, by other galaxies
18:37
Speaker 1: coming nearby and the gravitational tidal forces. It's a dangerous universe.
18:41
Speaker 1: When you send your galaxies out there into the wild,
18:43
Speaker 1: you don't know what's going to happen. And make sure
18:45
Speaker 1: they look both ways before crossing the universal streets. All right,
18:50
Speaker 1: let's talk about what is still around and what might
18:54
Speaker 1: be the oldest thing in the universe still alive today.
18:59
Speaker 1: But first it's take a quick break. All right, we're
19:14
Speaker 1: talking about what is the oldest thing in the universe,
19:17
Speaker 1: and so Daniel, we were talking about a galaxy that
19:20
Speaker 1: was around thirteen point four billion light years away, But
19:24
Speaker 1: you're saying that's not necessarily something that is still around today,
19:28
Speaker 1: meaning that like what we're looking at is stuff that
19:32
Speaker 1: was in the past, but we can't tell if it's
19:36
Speaker 1: still around today. Yeah exactly. We don't know what's going
19:39
Speaker 1: on really far away right now because it's going to
19:43
Speaker 1: take that light another thirteen billion years to get here.
19:46
Speaker 1: So if we want to talk about what the oldest
19:48
Speaker 1: thing in the universe is, we need to look at
19:50
Speaker 1: stuff that's kind of nearby to us, that's kind of
19:53
Speaker 1: close so it doesn't take the light so long to
19:55
Speaker 1: get here, so we can see it that it's still around.
19:58
Speaker 1: But it feels like a you know, like a loophole
20:01
Speaker 1: or like a paradox almost, like you know, we can
20:04
Speaker 1: only tell if it's old by looking at it, but
20:08
Speaker 1: we can only confirm how old it is if the
20:11
Speaker 1: light is old that we're seeing of it. Do you
20:14
Speaker 1: know what I mean? Well, if there was something that
20:16
Speaker 1: was created in the very early universe nearby and still around,
20:20
Speaker 1: and we could somehow measure its age, then that could
20:23
Speaker 1: be crowned as the oldest thing in the universe. It
20:25
Speaker 1: wouldn't take light very long to get here from it
20:28
Speaker 1: because it'd be nearby. I see. We have to see
20:32
Speaker 1: something old, is what you're saying, Yes, exactly, and not
20:35
Speaker 1: just a really old picture of it. Yeah, we want
20:37
Speaker 1: something around now that's old, not just old information about
20:40
Speaker 1: something that existed a long time ago, which might not
20:43
Speaker 1: be around anymore. You see. It's not like you're trying
20:46
Speaker 1: to ask, what is the oldest baby picture of a
20:50
Speaker 1: person you can find. You're trying to ask like, who
20:53
Speaker 1: is the oldest French lady living in an apartment that
20:56
Speaker 1: we can talk to today? Exactly? And both are fascinating questions.
20:59
Speaker 1: And I want to see the oldest baby picture ever.
21:02
Speaker 1: That's actually a really cool question. What is the oldest
21:05
Speaker 1: baby picture? Who was the first baby to ever be photographed?
21:08
Speaker 1: I don't even know the answer to that. And that's
21:09
Speaker 1: why we do look really far away to look back
21:12
Speaker 1: in time, because we want to know the original history
21:15
Speaker 1: of the universe. But that doesn't tell us who's still
21:17
Speaker 1: around today. So yeah, I want to see the astrophysical
21:20
Speaker 1: equivalent of the oldest French lady. All right, So let's
21:23
Speaker 1: start in our neighborhood. I guess in our galaxy, what's
21:26
Speaker 1: the oldest I don't know, star or cloud that we
21:29
Speaker 1: can see. Yeah, things get pretty old right around in
21:32
Speaker 1: our neighborhood. Now, our star is only about five billion
21:36
Speaker 1: years old. It's formed just under five billion years ago
21:39
Speaker 1: from collapse of a big cloud of gas and dust
21:42
Speaker 1: and bits of other stars. Right, that's about five billion
21:45
Speaker 1: years ago, But the Milky Way itself is much older,
21:48
Speaker 1: and there are older stars right here in our Milky Way,
21:52
Speaker 1: much much older. How old are we to, Well, what's
21:55
Speaker 1: the oldest star we can see here in our galaxy? Yeah,
21:57
Speaker 1: there's a star here that goes by the awesome aime
22:00
Speaker 1: of h D one zero to eight three, and at
22:04
Speaker 1: least it's you know, that's a big plus twenty years ago.
22:08
Speaker 1: We're trying to upgrade it to four K but it
22:10
Speaker 1: costs a lot of money and it has a really
22:12
Speaker 1: weird age. So, you know, the universe is just under
22:15
Speaker 1: fourteen billion years old, this star is fourteen and a
22:18
Speaker 1: half billion years old, which is weird, Like, what, yeah,
22:22
Speaker 1: how can the star be older than the universe. Well,
22:24
Speaker 1: it turns out there's a big uncertainty on that measurement.
22:27
Speaker 1: It's fourteen and a half plus or minus point eight
22:30
Speaker 1: billion years, so it's almost a billion years of uncertainty.
22:34
Speaker 1: But it's super wow. Wait, and it's right here in
22:37
Speaker 1: our backyard. Yeah, it's only two hundred light years away.
22:41
Speaker 1: It's like pretty close by. It's one of the closer
22:44
Speaker 1: stars in our galaxy, and it's the oldest star we've
22:48
Speaker 1: seen in the galaxy. Wow, or maybe ever? Is it possible? Ever? Yes, absolutely,
22:53
Speaker 1: it's one of the oldest stars known in the universe.
22:55
Speaker 1: Of course, it's much easier to measure the age of
22:57
Speaker 1: stars in our galaxy than in other galaxies. But yeah,
23:01
Speaker 1: it's one of the oldest stars in our galaxy and
23:03
Speaker 1: in the universe it's crazy old. Yeah, because we we
23:06
Speaker 1: can't really see stars in other galaxies, right, I mean,
23:09
Speaker 1: unless it's like a supernova or something super duper bright.
23:13
Speaker 1: But generally speaking, you know, most of the stars that
23:16
Speaker 1: you've seen in the night sky are in the galaxy. Yeah, exactly.
23:19
Speaker 1: You can if you have a very powerful telescope sometimes
23:21
Speaker 1: resolve stars and other galaxies, as you say, if they're
23:24
Speaker 1: very very bright. But most of the stars we're looking
23:27
Speaker 1: at the constellations, for example, this is just the rest
23:30
Speaker 1: of the Milky Way. We're embedded in it, and as
23:32
Speaker 1: we look out into the night sky, those are the
23:34
Speaker 1: stars we see. And this star here is really old
23:37
Speaker 1: and it's lasted a long time because it's pretty small,
23:41
Speaker 1: like these stars don't burn very quickly. A really big
23:44
Speaker 1: star burns really fast, and a really small star burns
23:48
Speaker 1: much slower, and so it can sort of like stretch
23:50
Speaker 1: its fuel out much longer. It just sits there, simmering,
23:55
Speaker 1: simmering and anger and being small. Exactly, it's grumpy and
24:00
Speaker 1: even it literally comes from a previous generation of stars,
24:03
Speaker 1: Like our sun is made out of the destroyed bits
24:07
Speaker 1: of this second generation stars. So there was the first
24:10
Speaker 1: generation that burned really quickly, then the second generation that
24:13
Speaker 1: had a little bit of heavier metals in them from
24:16
Speaker 1: the remnants of that first generation, and then our star
24:20
Speaker 1: is born in the third generation of stars, the remnants
24:23
Speaker 1: of the second generation. This one h D whatever is
24:26
Speaker 1: actually still from that second generation of stars. It's still around,
24:29
Speaker 1: and so it's it's pretty old. It's I feel like
24:31
Speaker 1: it's a fourteen point five billion years old. It's almost
24:34
Speaker 1: as old as the universe itself. Is it older than
24:37
Speaker 1: the Milky Way, Then it's almost as old as the
24:39
Speaker 1: universe itself. You're exactly right. We don't know if it's
24:42
Speaker 1: older than the Milky Way. We know the Milky Way
24:44
Speaker 1: is about thirteen and a half billion years old. It's
24:47
Speaker 1: almost as old as the universe. It's a galaxy that
24:50
Speaker 1: formed very very early on, so like it's as old
24:54
Speaker 1: as that galaxy we talked about g n Z eleven
24:57
Speaker 1: that's thirteen and a half billion light years away. We
25:00
Speaker 1: have pictures of that one from when it was forming
25:02
Speaker 1: the thirteen and a half billion years ago. But our
25:05
Speaker 1: galaxy was also forming thirteen and a half billion years ago,
25:09
Speaker 1: so we live in an ancient neighborhood. It's almost like
25:12
Speaker 1: the star was around when the galaxy was formed, when
25:14
Speaker 1: the Milky Way was being born. Yeah, and you know,
25:17
Speaker 1: there's a bit of a definitional question there because galaxies
25:19
Speaker 1: are formed from stars as they come together. And we
25:23
Speaker 1: talked to the podcast once about how the structure of
25:25
Speaker 1: the universe formed and how it's influenced by dark matter,
25:28
Speaker 1: and we're pretty sure that the structure forms bottom up,
25:31
Speaker 1: that you know, stars collapse and then are gathered together
25:33
Speaker 1: into galaxies rather than like huge sheets of matter breaking
25:37
Speaker 1: off into chunks which then separate into galaxies and separate
25:41
Speaker 1: into stars. So we think it's stars before galaxies that
25:44
Speaker 1: like galaxies are formed out of stars that have coalesced
25:47
Speaker 1: from early blobs of gas and dust. All right, So
25:51
Speaker 1: this planet may have been around when all that was
25:53
Speaker 1: happening in our galaxy. But I guess the question is,
25:57
Speaker 1: how do we know how old this star is? Mean,
26:00
Speaker 1: it's just a big ball of simmering resentment or fire.
26:04
Speaker 1: How can you tell how old it is? I mean,
26:06
Speaker 1: does it look different than it did billion years ago?
26:09
Speaker 1: You can tell by how well it plays scrabble. Actually
26:11
Speaker 1: that's pretty good predictor. You know, it's really hard to
26:15
Speaker 1: measure the age of one star. It's very difficult because stars,
26:19
Speaker 1: when they burn, like our sun, look mostly the same
26:22
Speaker 1: from most of their lifetime. Like our son. We expect
26:25
Speaker 1: to have about a ten billion year lifetime. We're about
26:27
Speaker 1: halfway through it, and it's not going to look very
26:29
Speaker 1: different now and in a billion years and in four
26:33
Speaker 1: billion years. It looks pretty different at the very beginning
26:35
Speaker 1: as it's forming, and it's pretty exciting stuff happens at
26:38
Speaker 1: the end when it's fizzling out. But in that intermediate time,
26:42
Speaker 1: it's really hard to nail down the age of a
26:44
Speaker 1: star just by looking at it. But wait, how so then,
26:47
Speaker 1: how can we tell how old our star is? Yeah? So,
26:49
Speaker 1: mostly the way we tell the age of stars is
26:52
Speaker 1: not by telling the age of individual stars. But by
26:54
Speaker 1: looking at star clusters groups of stars, because we think
26:58
Speaker 1: that they are formed together, that like these big clouds
27:01
Speaker 1: of gas and dust smashed together or something happens to
27:04
Speaker 1: trigger star formation, and you get these clusters of stars
27:07
Speaker 1: that are all the same age. Now, you can't tell
27:09
Speaker 1: the individual age of a starter easily, so how could
27:12
Speaker 1: you tell the age of a whole cluster. Well, the
27:14
Speaker 1: cool thing about a cluster is that it has stars
27:16
Speaker 1: of different sizes, as bigger ones and smaller ones. So
27:20
Speaker 1: if it gets old enough, then you start to see
27:22
Speaker 1: a few of those stars burn out. They go from
27:25
Speaker 1: like being a normal star to being like a red
27:27
Speaker 1: giant in the last phases of their life. And when
27:30
Speaker 1: that happens, you can measure the age of a star.
27:32
Speaker 1: You can measure it when it's starting to fizzle out. Oh,
27:34
Speaker 1: I see, but you don't actually see it fizzle out.
27:36
Speaker 1: You just see like if you see a red giant.
27:38
Speaker 1: You know that red giants don't last very long, so
27:41
Speaker 1: it must have happened recently. Yeah, exactly. So you look
27:44
Speaker 1: at a whole group of stars and you look at
27:45
Speaker 1: this population, you say, oh, some of them have started
27:47
Speaker 1: to fall off onto this red giant track, and once
27:50
Speaker 1: you look at that star, you can see how big
27:52
Speaker 1: it is, and then you can tell how bright it's burning,
27:55
Speaker 1: like how fast it was using its fuel, And now
27:57
Speaker 1: that you know it's turned off on the Red Giant track,
28:00
Speaker 1: give an idea of how long it took to burn
28:02
Speaker 1: that fuel, so you can figure out like, okay, it
28:04
Speaker 1: must be seven billion years old or something, and then
28:07
Speaker 1: you can look at the whole cluster and say, oh,
28:09
Speaker 1: the whole cluster is about seven billion years old. Even
28:11
Speaker 1: though most of the stars individually you can't really tell
28:14
Speaker 1: anything about them because they're just burning happily. Still. Clusters
28:18
Speaker 1: do have signs of aging, but stars don't. So then
28:22
Speaker 1: how do we know that this particular star HD one
28:24
Speaker 1: four oh to eight three is fourteen and a half
28:27
Speaker 1: billion years old? Well, we don't know it very well.
28:30
Speaker 1: And the reason is that it's not part of a cluster.
28:32
Speaker 1: It's just like out there on its own, called these
28:35
Speaker 1: field stars. They're just like loners, you know, and a
28:38
Speaker 1: loner star it's really hard to tell its age. We
28:40
Speaker 1: have some ways of doing it, like we have models
28:43
Speaker 1: for how stars age as they get older. You know,
28:46
Speaker 1: they change their spin rate for example, or the color
28:50
Speaker 1: changes a little bit. But these methods are much less reliable,
28:53
Speaker 1: much less precise than looking at a whole star cluster.
28:56
Speaker 1: And that's why there's so much uncertainty, Like fourteen and
28:59
Speaker 1: a half plus or minus point eight is a big uncertainty,
29:03
Speaker 1: And the reason is that it's by itself. We have
29:05
Speaker 1: to use these models and make a lot of theoretical
29:07
Speaker 1: assumptions about how stars look. So that's why we're not
29:10
Speaker 1: so sure. I see, I see. We just think it's
29:13
Speaker 1: fourteen and a halfpenion years old from what we can
29:16
Speaker 1: tell of it. Yeah, you know, we see a bunch
29:18
Speaker 1: of wrinkles and we think, wow, that looks like an
29:20
Speaker 1: old star. If it was hanging out with all of
29:22
Speaker 1: its friends and half of them had died already, would
29:24
Speaker 1: be more confident that it was really old. But we
29:28
Speaker 1: can't really pin it down as well. Maybe that's a
29:29
Speaker 1: secret to old age. Daniel don't don't have any friends.
29:33
Speaker 1: That's a secret to looking old. Maybe that's the track
29:38
Speaker 1: I'm on. All right, Well, let's get into bigger things
29:42
Speaker 1: and maybe older things in our galaxy. But first let's
29:46
Speaker 1: take another quick break. All right, we're talking about the
29:59
Speaker 1: old thing in the universe, and Daniel. Why I think
30:02
Speaker 1: we mean like an organization of matter, because there is
30:06
Speaker 1: matter in the universe that is still around from the
30:09
Speaker 1: Big Bang, right, Like, like protons and electrons were all
30:12
Speaker 1: sort of born in the Big Bang. Yeah, there's a
30:14
Speaker 1: lot of stuff left over from the Big Bang. And
30:16
Speaker 1: so if you call protons a thing or electrons a thing,
30:19
Speaker 1: then some of those could be almost as old as
30:22
Speaker 1: the universe. Remember the very first moments of the universe,
30:25
Speaker 1: there weren't protons and electrons and particles, and the way
30:28
Speaker 1: we think about them, things were so hot and so
30:30
Speaker 1: dense and so crazy. There was so much energy slashing
30:34
Speaker 1: around in the field that didn't really like get discretized
30:37
Speaker 1: and localized into what we think of now as particles.
30:40
Speaker 1: It's like you had an ocean. You don't think about
30:42
Speaker 1: any individual marine drops, right. And for the most part,
30:45
Speaker 1: electrons and protons, which are made out of orcs, they
30:48
Speaker 1: don't really disappear or appear all of a sudden, right Like.
30:52
Speaker 1: They hang around. They might change from being a star
30:54
Speaker 1: to being dust to being people. But pretty much the
30:58
Speaker 1: things were made out of have been around maybe since
31:00
Speaker 1: the Big Bang, Yeah, exactly. Now you can annihilate a
31:03
Speaker 1: proton or an electron. We smash a lot of protons
31:06
Speaker 1: every day at the Large Adron Collider, and electrons. If
31:09
Speaker 1: they hit a positron, they can turn into a photon,
31:11
Speaker 1: so it's possible to kill them. They're not immortal in
31:14
Speaker 1: that way, but on their own they are a stable.
31:16
Speaker 1: You have an electron just sitting in space, it will
31:19
Speaker 1: stay there as an electron forever, and the same we
31:22
Speaker 1: think for a proton. So you're right that some of
31:24
Speaker 1: the protons and electrons in us may be as old
31:28
Speaker 1: as any particle in the universe. That could be the
31:30
Speaker 1: first generation of particles ever made. Can you imagine me
31:34
Speaker 1: in a proton that old, like you've survived fifteen billion
31:38
Speaker 1: years and then only to be sucked into a particle
31:41
Speaker 1: collider by some physicists and then be killed that way.
31:44
Speaker 1: I don't know. I'd rather be in an excitement of
31:46
Speaker 1: a particle collider than like end up as somebody's tone
31:48
Speaker 1: nail or both. I mean, if you get to do both,
31:53
Speaker 1: that might be better. Well, we are working on a
31:55
Speaker 1: tonail collider, so yeah, you could be both. That would
31:57
Speaker 1: be quite a feat. Oh, I don't know what to
32:05
Speaker 1: say to that. You just put your foot in my mouth.
32:09
Speaker 1: All right, So that star might be the oldest thing
32:11
Speaker 1: that we know about, or it may not, because there's
32:14
Speaker 1: a big uncertainty about it. But what else we think
32:17
Speaker 1: is maybe as old or older than this star in
32:20
Speaker 1: our galaxy? Well, there are black holes, right. Black holes
32:23
Speaker 1: are fascinating mysterious objects we'd like to understand better. There
32:27
Speaker 1: are ones at the centers of our galaxy. There are
32:30
Speaker 1: individuals stellar black holes floating around. And then there's the
32:33
Speaker 1: possibility that there are primordial black holes. Black holes formed
32:38
Speaker 1: in the first moments of the Big Bang, maybe even
32:41
Speaker 1: before protons were made. Wow, wait, what black hole? That's
32:45
Speaker 1: that are older than particles, older than particles. We had
32:48
Speaker 1: a whole fun episode about primordial black holes. And remember
32:52
Speaker 1: that the very early universe things were hot and dense,
32:55
Speaker 1: and we talked about why there wasn't just like a
32:57
Speaker 1: whole universe size black hole in the very big ending,
33:00
Speaker 1: because you need like localized pockets of over density for
33:03
Speaker 1: stuff to gather together to make a black hole. You
33:06
Speaker 1: can't just have the whole universe be a black hole.
33:08
Speaker 1: But after things spread out a little bit, that's exactly
33:10
Speaker 1: what you had. You had pockets of very dense matter
33:13
Speaker 1: that were more dense than the neighboring stuff, and so
33:16
Speaker 1: it's possible that some of those formed black holes, which
33:19
Speaker 1: could still be around today. Nobody's ever seen one of
33:22
Speaker 1: these black holes, these primordial ones, but we can't prove
33:25
Speaker 1: that they don't exist, and some people think they might
33:28
Speaker 1: even be a good candidate for dark matter. Wait, meaning
33:30
Speaker 1: that the black hole is made out of dark matter.
33:32
Speaker 1: That dark matter is made out of black holes, right right,
33:36
Speaker 1: like little tiny black holes floating around in space. Yeah,
33:39
Speaker 1: because we know there's more stuff out there that has
33:41
Speaker 1: gravity that we can't explain, and black holes fit the
33:44
Speaker 1: bill because they are massive and they are dark, and
33:48
Speaker 1: they would have been created before the quarks, and so
33:50
Speaker 1: they would explain why these things can't be made out
33:53
Speaker 1: of quarks. So it's a really fun idea that primordial
33:55
Speaker 1: black holes could be out there. In fact, there's even
33:58
Speaker 1: this idea that there's another planet in our Solar system
34:01
Speaker 1: because people have seen weird tugs on Neptune and Uranus
34:05
Speaker 1: that they can't explain without some kind of dark, massive
34:08
Speaker 1: object out there tugging on them gravitationally, and some folks
34:11
Speaker 1: think it might be a primordial black hole. And remember
34:15
Speaker 1: these things are small, Like a black hole with the
34:17
Speaker 1: mass of a planet would be about the size of
34:19
Speaker 1: a tennis ball, so it would be pretty easy to miss.
34:22
Speaker 1: You don't want to play tennis with that unless you
34:24
Speaker 1: have a pretty good racket. You can really hit a
34:29
Speaker 1: planet mass ball very hard. Anyway, just like smashing your
34:33
Speaker 1: tennis racket on the ground, it doesn't really do anything
34:35
Speaker 1: to the trajectory of the planet. And so this primordial
34:38
Speaker 1: black hole could be in our in our own solar system,
34:40
Speaker 1: so like maybe the oldest thing in our universe, we
34:43
Speaker 1: could be really nearby. It could be pulling on us
34:46
Speaker 1: right now. It could be in fact. But one of
34:48
Speaker 1: the really interesting things about black holes is that you
34:50
Speaker 1: cannot tell their age. Remember, black holes hide information that
34:54
Speaker 1: give out nothing about what's inside them. The only thing
34:57
Speaker 1: you can know about a black hole is it's mas us,
35:00
Speaker 1: it's spin, and its electric charge. And that means that
35:03
Speaker 1: it's impossible to know the age of a black hole,
35:05
Speaker 1: the same way you can't know the age of a proton.
35:08
Speaker 1: Black Holes are like quantum mechanically indistinguishable from each other.
35:12
Speaker 1: If they have the same mass, charge and spin. They're
35:15
Speaker 1: like the canoes of the universe can't tell how old
35:18
Speaker 1: they are. That's right, yeah, exactly, though his career is
35:23
Speaker 1: not exactly a black hole. But you know, if you
35:26
Speaker 1: form a black hole yesterday and you form a black
35:28
Speaker 1: hole a billion years ago with the same amount of mass,
35:30
Speaker 1: they will look totally identical. There's no way to get
35:33
Speaker 1: any information but when that stuff went into the black hole,
35:37
Speaker 1: which is pretty fascinating. But it also means that even
35:40
Speaker 1: if we saw a primordial black hole, we wouldn't know
35:42
Speaker 1: how old it was. And but and again these are theoretical.
35:46
Speaker 1: We haven't seen any of these. But what about the
35:49
Speaker 1: ones like at the center of galaxies, like at the
35:51
Speaker 1: center of our galaxies? Are those made out of primordial
35:54
Speaker 1: black holes or do we know for sure they were
35:57
Speaker 1: formed more recently. We don't know. And one of the
36:00
Speaker 1: mysteries of those black holes is that they're really, really big.
36:03
Speaker 1: We can't explain how they got so big so fast.
36:06
Speaker 1: Our models of galaxy formation suggests that those black holes
36:10
Speaker 1: should be smaller. One way to make them bigger. To
36:12
Speaker 1: explain the mystery of super massive black holes is if
36:15
Speaker 1: they were actually seated with pretty big primordial black holes
36:19
Speaker 1: from the Big Bang. But that's just an idea we
36:21
Speaker 1: don't understand. But if they were formed just from like
36:24
Speaker 1: stars and gas and dust collapsing into a black hole,
36:27
Speaker 1: which is possible, then there would be as old as
36:30
Speaker 1: our galaxy and probably less old than the stars in
36:34
Speaker 1: our galaxy. Yeah, like, we know how old our galaxy is,
36:37
Speaker 1: but do we know of other galaxies out there that
36:40
Speaker 1: might be older than ours? Well, we do live in
36:42
Speaker 1: one of the oldest galaxies, one of the oldest neighborhoods
36:45
Speaker 1: in the universe, and as we look at the galaxies
36:47
Speaker 1: around us, we see that they're all pretty old. The
36:50
Speaker 1: galaxies nearby seem to be about ten billion to thirteen
36:54
Speaker 1: and a half billion years old, so there're no like new,
36:57
Speaker 1: fresh galaxies in the neighborhood. But wait, how do we
37:00
Speaker 1: know how old they are? It is pretty rude. We
37:04
Speaker 1: have two ways to measure the age of galaxies. One
37:06
Speaker 1: is just to look at the stuff inside of it
37:08
Speaker 1: and say, like, can we see old populations of stars?
37:12
Speaker 1: And this works for nearby galaxies where we can actually
37:15
Speaker 1: resolve a few of the stars and the star clusters
37:18
Speaker 1: and play the same trick where we try to see
37:20
Speaker 1: some of those clusters having stars that die off, but
37:23
Speaker 1: it's pretty hard because those galaxies are pretty far away.
37:26
Speaker 1: Another way to do it is to look at the
37:28
Speaker 1: like the overall light from the galaxy, and look at
37:31
Speaker 1: the ratio of various heavy elements, because as the galaxy
37:35
Speaker 1: gets older, the stars have burned more of the light
37:38
Speaker 1: elements and turned them into heavier stuff. Remember that's what
37:41
Speaker 1: happens at the heart of stars. You turn light elements
37:43
Speaker 1: like hydrogen and helium or whatever into heavier stuff like
37:46
Speaker 1: magnesium and eventually iron. So if you look at the
37:50
Speaker 1: ratio of magnesium to iron, you can start to see
37:53
Speaker 1: this change as the galaxy gets older. And so this
37:56
Speaker 1: works mostly for younger galaxies that are far away, and
38:00
Speaker 1: this sort of number is rapidly changing as the stars collapse.
38:03
Speaker 1: For older galaxies, it's not as effective because it ends
38:06
Speaker 1: up pretty stable. You end up with a lot of
38:08
Speaker 1: stars like our sun, and the amount of iron is
38:11
Speaker 1: not changing quickly. And we can tell these proportions from
38:15
Speaker 1: the light right like the light these galaxies give off
38:19
Speaker 1: sort of tell us what kind of stuff is in it. Yeah, exactly.
38:22
Speaker 1: We can't go out and scoop up a chunk of
38:24
Speaker 1: that galaxy and then measure it, though we'd love to
38:27
Speaker 1: and you know, NASA comes up with an idea for
38:29
Speaker 1: building wormholes to do it. I would definitely pay more
38:31
Speaker 1: in taxes to make that happen. But you're right. The
38:34
Speaker 1: only way to probe those galaxies to look at the
38:36
Speaker 1: light that comes from them, and the light is like
38:39
Speaker 1: a fingerprint that tells you what's in a galaxy because
38:42
Speaker 1: different kinds of stuff glow at different frequencies. You know,
38:46
Speaker 1: every kind of element has a different arrangement of electrons,
38:48
Speaker 1: and it's the wiggling and jumping of those electrons that
38:51
Speaker 1: give off the light. So there's like a fingerprint for
38:53
Speaker 1: every element. You can tell what contributions there are from
38:56
Speaker 1: every element just by looking at the spectrum of the light,
38:59
Speaker 1: which frequently sees have a lot of light in which
39:01
Speaker 1: frequencies don't have a lot of light. All right, So
39:03
Speaker 1: that's galaxies. They are maybe about thirteen point six billion
39:07
Speaker 1: years old, but they're kind of far away, so we
39:10
Speaker 1: also have to kind of account for the fact that
39:11
Speaker 1: they may not still be around today. Yeah, we're pretty
39:14
Speaker 1: sure Andromeda is there, for example, but yeah, you never
39:17
Speaker 1: really know because you're looking at stuff that's millions or
39:19
Speaker 1: billions of years old. Yeah, it could have been crossing
39:22
Speaker 1: the universe street and who knows. All right, so is
39:25
Speaker 1: that then the oldest large scale structure in the universe
39:28
Speaker 1: or can we see older, bigger things. There are things
39:32
Speaker 1: probably older than galaxies that probably formed before galaxies. So
39:37
Speaker 1: we talked about how in the early universe you had stars,
39:39
Speaker 1: and the stars gathered together to make galaxies, but not
39:42
Speaker 1: every club of stars was destined to make like a
39:44
Speaker 1: full on galaxy. Sometimes they make something smaller called a
39:48
Speaker 1: globular cluster. These things are really amazing and we're gonna
39:52
Speaker 1: have to do a whole podcast episode just about globular
39:55
Speaker 1: clusters and you know who give them that name. But
39:58
Speaker 1: these are like non ga see blobs of stars usually
40:02
Speaker 1: orbiting a galaxy. Interesting and what makes them a blob
40:05
Speaker 1: and not a galaxy? I guess is it just like um,
40:07
Speaker 1: it doesn't form need swirls or is there something more
40:11
Speaker 1: fundamental about them? It's their fundamental blobbiness. Yeah, absolutely, that's
40:14
Speaker 1: a That's a thing that visits now is that they're
40:17
Speaker 1: smaller than galaxies. There's like a hundred thousand stars and
40:21
Speaker 1: so there's just not big enough to form the interesting structures.
40:24
Speaker 1: And there's also just like a naming convention. You know,
40:26
Speaker 1: things that are smaller that are orbiting actual galaxies, You
40:29
Speaker 1: call them a globular cluster, all right, And so those
40:31
Speaker 1: we can tell are older than the galaxies. How can
40:34
Speaker 1: we tell their age. We can tell their age by
40:37
Speaker 1: looking at the stars inside them and playing the same game.
40:39
Speaker 1: And the interesting thing is that a lot of these
40:41
Speaker 1: clusters seem to have stars all the same age, like
40:44
Speaker 1: they all formed at once and then just sort of
40:47
Speaker 1: like gathered together to make this cluster. And there's one
40:51
Speaker 1: that's pretty nearby. It's like eight thousand light years away,
40:54
Speaker 1: and it looks like it's really really old. Well, it's
40:57
Speaker 1: super close, I mean speaking in the skill of the universe,
41:01
Speaker 1: eight thousand nine years away, eight thousand light years away.
41:04
Speaker 1: It's like a satellite to our galaxy. It's orbiting the
41:07
Speaker 1: Milky Way. It's like a little blob that's like moving
41:09
Speaker 1: around the Milky Way. And when we look at this thing,
41:12
Speaker 1: it looks like it's about thirteen and a half billion
41:15
Speaker 1: years old. It's got the sexy name of n g
41:18
Speaker 1: C sixty nineties. I love how ustromers go for sexy names.
41:24
Speaker 1: If you if you like numbers, if you like numbers. Well,
41:26
Speaker 1: they just see so many things, right, how can they
41:29
Speaker 1: give them all individual names? It's like if you had
41:31
Speaker 1: a billion children, would you come up with creative, beautiful
41:34
Speaker 1: names for each of them where you start numbering them.
41:36
Speaker 1: I think I would probably be dead if I don't
41:39
Speaker 1: have any children. You would definitely be broke. All right, So, um,
41:44
Speaker 1: it sounds like there's a galaxy globular cluster that's thirteen
41:50
Speaker 1: point four billion years old. There's our galaxy is also
41:53
Speaker 1: kind of that old. About that old? Um, there's a
41:56
Speaker 1: star in our galaxy that we can tell is maybe
41:59
Speaker 1: about that old, And there are far away galaxies we
42:02
Speaker 1: think might be that old, or at least we're alive
42:04
Speaker 1: back then. I guess the question then, is, Daniel, who
42:06
Speaker 1: do we give the award to? Who? What is the
42:08
Speaker 1: oldest thing in the universe? Whoever is willing to come
42:11
Speaker 1: and be a guest on the podcast? That's we could
42:13
Speaker 1: the award to have to break the tie somehow. I see,
42:17
Speaker 1: whoever comes into tux and stays within the acceptance speech limit.
42:22
Speaker 1: Yeah no, but you're right, we don't exactly know what
42:24
Speaker 1: is the oldest thing in the universe. It could be
42:26
Speaker 1: one of these stars which came together to form some
42:29
Speaker 1: of these galaxies and globular clusters, but we're not sure.
42:33
Speaker 1: It could be one of the black holes that's floating
42:35
Speaker 1: around I think. I think to take away is that
42:37
Speaker 1: there's a lot of really old stuff nearby. You don't
42:40
Speaker 1: have to look into the depths of the universe to
42:43
Speaker 1: see stuff that was created a long time ago, and
42:46
Speaker 1: this stuff is still around. So there's a lot of
42:48
Speaker 1: like awesome archaeology about the early days of the universe.
42:52
Speaker 1: What was it like to be around a few hundred
42:54
Speaker 1: million years after the Big Bang? Is evidence for that
42:57
Speaker 1: right here in our backyard, because I guess we are
43:00
Speaker 1: like still in the middle of the universe, right, Like
43:02
Speaker 1: we're not out far away from where the action is.
43:04
Speaker 1: You can still see things today around this that we're
43:07
Speaker 1: around maybe around the time of the Big Bang. Yeah,
43:10
Speaker 1: there's not really any middle of the universe, but yeah,
43:12
Speaker 1: we're in the center of the action, that's for sure.
43:14
Speaker 1: There's plenty of good stuff all around here to tell
43:17
Speaker 1: us about what happened in the very early days of
43:19
Speaker 1: the universe, and we get to watch it age. We
43:21
Speaker 1: get to see, like when many stuff going to burn out,
43:23
Speaker 1: what is the lifespan of a star cann go for
43:26
Speaker 1: twenty thirty billion years. Well, my money is still on
43:29
Speaker 1: that French old lady. I think she's going to outlive
43:32
Speaker 1: us all and the rest of the universe. That's right,
43:35
Speaker 1: and she'd probably still beat us all at scrabble. All right. Well,
43:37
Speaker 1: we hope you enjoyed that and maybe think a little
43:40
Speaker 1: bit about the age of the universe and maybe makes
43:42
Speaker 1: you appreciate a little bit of our time in it,
43:45
Speaker 1: because it is a pretty short clip in such an
43:47
Speaker 1: old universe. Thanks for joining us, See you next time.
43:58
Speaker 1: Thanks for listening, and remember that Daniel and Jorge Explain
44:01
Speaker 1: the Universe is a production of I Heart Radio. For
44:04
Speaker 1: More podcast for my Heart Radio, visit the I Heart
44:07
Speaker 1: Radio Apple Apple Podcasts, or wherever you listen to your
44:11
Speaker 1: favorite shows. Yea