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What are globular clusters? · Daniel and Kelly’s Extraordinary Universe

0:08
Speaker 1: Hey, Katie, do you have science words that you especially like? Yeah,
0:13
Speaker 1: I really like apoptosis. It makes me think of popcorn.
0:17
Speaker 1: That does make me want to have a snack. Well,
0:20
Speaker 1: I like the word fundamental. It sounds so important, it's
0:25
Speaker 1: got fun in it, it does. So what science words
0:30
Speaker 1: don't you like? Um, coagulate, I was afraid you're gonna
0:35
Speaker 1: say moist coagulates pretty gross. Also, I'm not such a
0:39
Speaker 1: fan of the word had drawn. No, the problem is
0:43
Speaker 1: a lot of people end up with a little typo
0:45
Speaker 1: that swaps a couple of letters and you end up
0:47
Speaker 1: with something very not safe for work. Yeah, that gives
0:51
Speaker 1: the lard hay drown collider a whole different connotation. Hi,
1:11
Speaker 1: I'm Daniel, I'm a part of Old Physicist, and I
1:14
Speaker 1: definitely am colliding hay drowns at the LHC. And I
1:19
Speaker 1: am Katie Golden. I'm stepping in for Jorge this week,
1:23
Speaker 1: and I am the host of Creature Feature. I'm a
1:26
Speaker 1: science podcast interested in evolutionary biology, human psychology, and hate
1:31
Speaker 1: also physics and Welcome to the podcast. Daniel and Jorge
1:36
Speaker 1: explain the universe, in which we take you on a
1:39
Speaker 1: mental journey to understand everything about the universe, from the
1:43
Speaker 1: tiniest things between your toes to the things you see
1:46
Speaker 1: in the night sky to the vast weird, crazy bonker
1:50
Speaker 1: stuff going out in the depths of space. We take
1:53
Speaker 1: all of it, roll it up and try to make
1:55
Speaker 1: sure that you understand it. Like a cosmic burrito. How
2:01
Speaker 1: much hot sauce you want is up to you. And
2:04
Speaker 1: we love to talk about stuff that we see in
2:07
Speaker 1: the night sky, but we also love to talk about
2:09
Speaker 1: stuff you might not have even heard of. When you
2:13
Speaker 1: look up in the sky, you see stars, and if
2:15
Speaker 1: you have a nice telescope you can even see further
2:17
Speaker 1: in meb see those smudges that our galaxies. But there's
2:21
Speaker 1: a lot of other stuff out there in the universe
2:23
Speaker 1: that we are not familiar with, that most people don't
2:26
Speaker 1: even know exists. Okay, so if I'm looking at the
2:29
Speaker 1: night sky, I see a bunch of stars. Sometimes I
2:32
Speaker 1: see like, like you said, it looks like someone spilled
2:36
Speaker 1: a bunch of sugar up there, and it's a galaxy.
2:39
Speaker 1: But what can I possibly be missing? I mean other
2:42
Speaker 1: than yeah, I guess I can't see them in detail
2:45
Speaker 1: with a telescope, But but what what's up there? Like
2:48
Speaker 1: you mean giant alien eyeballs. Well, there's a lot of
2:52
Speaker 1: stuff out there. And basically, every time we turn on
2:55
Speaker 1: a new telescope or a new kind of device for
2:58
Speaker 1: we're listening to the Cosmos, we find something new. And
3:01
Speaker 1: every time we ap peer deeper and deeper into the sky,
3:04
Speaker 1: we see stuff that we didn't expect. On the podcast today,
3:08
Speaker 1: we'll be talking about a weird thing that's in the
3:10
Speaker 1: sky that astronomers have known about for hundreds of years,
3:14
Speaker 1: but most people aren't aware of. All Right, well, what's
3:18
Speaker 1: this big secret? What if astronomer has been keeping from us? Well,
3:22
Speaker 1: unfortunately it's got a really strange and kind of an
3:25
Speaker 1: ugly name. Oh, it's not coagulated. It stars don't coagulate.
3:32
Speaker 1: I guess if a galaxy cuts itself right, a bunch
3:34
Speaker 1: of like stars could rush in to fill in the
3:36
Speaker 1: gap planetary platelets. No, Today on the program, we'll be
3:41
Speaker 1: asking the question what are globular clusters? You? Doesn't sound
3:53
Speaker 1: like something you want to order on the menu, does it? No?
3:56
Speaker 1: It sounds like the worst kids cereal? Ever, like, be
4:01
Speaker 1: sure to get globios for your globular clusters. I know,
4:07
Speaker 1: I imagine some like scoop of some very viscous kind
4:10
Speaker 1: of stuff. It's like jello mixed with gravy or something.
4:13
Speaker 1: Oh man, I don't I have a texture thing when
4:16
Speaker 1: it comes to food, Like I don't like cottage cheese
4:20
Speaker 1: or other like things, little chunks suspended within goo. So
4:25
Speaker 1: I don't know about this globular clusters thing. This does
4:28
Speaker 1: not sound good. Well, fortunately it was not designed as
4:31
Speaker 1: a menu item. It's an astrophysical object. It's something out
4:34
Speaker 1: there in our universe that might teach us something about
4:37
Speaker 1: how the galaxy was formed, and how old the universe is,
4:40
Speaker 1: and weird new kinds of stars, and so it's an
4:43
Speaker 1: opportunity to learn something. Unfortunately, we don't actually have to
4:46
Speaker 1: taste it. That's good, that's good, all right. I'm still
4:49
Speaker 1: with you then, But if you try to give me
4:51
Speaker 1: a spoon on one of these globular clusters, I am check. Please.
4:57
Speaker 1: So we asked what people think globular clusters are, and
5:03
Speaker 1: this is what people have to say. I don't know
5:06
Speaker 1: what a globular clusters. I think it might be something
5:13
Speaker 1: found in out space, but I don't actually I'm not
5:18
Speaker 1: sure entirely, but I think it's just some type of
5:21
Speaker 1: grouping of stars, assuming it's a term from cosmology. A
5:25
Speaker 1: cluster is a collection of stars, and globular means that
5:30
Speaker 1: it's round like a globe, and you'll as in molecule
5:34
Speaker 1: or module, suggests that it's small, so it's a small
5:38
Speaker 1: round a bunch of stars. This one is like a
5:44
Speaker 1: gathering of stars spherical. It's not a galaxy. It can
5:51
Speaker 1: be within a galaxy, but it may look like a galaxy,
5:56
Speaker 1: like a spherical galaxy. I've heard the phrase globular or cluster.
6:01
Speaker 1: I'm not sure what it means. I thought that it
6:04
Speaker 1: had something to do with a group of stars, maybe
6:09
Speaker 1: that are clustered together in a spherical shape. This is
6:13
Speaker 1: a gigantic group of stars sit outside and I think
6:20
Speaker 1: maybe even all of it the galaxies. This has something
6:23
Speaker 1: to do with a group of stars, maybe that they
6:26
Speaker 1: all formed from the same nebula or um other event.
6:31
Speaker 1: Thanks to everybody who volunteered to speculate baselessly without getting
6:36
Speaker 1: to do any research or googling. If you'd like to
6:39
Speaker 1: participate for a future episode, please write to me two
6:42
Speaker 1: questions at Daniel and Jorge dot com. I think it's interesting,
6:46
Speaker 1: so most of the answers more along the same lines
6:49
Speaker 1: like this is probably a big cluster of stars or
6:54
Speaker 1: some kind of space junk, some kind of space junk.
6:59
Speaker 1: But then no clue in there that it's a cluster
7:01
Speaker 1: of stars, right, it could have been a cluster of anything,
7:04
Speaker 1: you know, jello or gravy or breakfast cereal or whatever.
7:08
Speaker 1: I think when people think about space, you think of
7:11
Speaker 1: it mostly stars. Right, you look out into space. What
7:15
Speaker 1: do you see? You see stars. All the other stuff
7:18
Speaker 1: that is out there is either hard to see or
7:21
Speaker 1: isn't really perceivable. Yeah, but you hear some people speculating
7:26
Speaker 1: like maybe it's a cluster of galaxies or a cluster
7:29
Speaker 1: of galaxy clusters or something like that, because there's this
7:32
Speaker 1: fascinating sort of hierarchy of structure out there in space. Right,
7:37
Speaker 1: It's not like they're just stars everywhere. Things are sort
7:40
Speaker 1: of grouped together into galaxies, and those galaxies are grouped
7:43
Speaker 1: together into clusters of galaxies, and so there's like this
7:46
Speaker 1: really fascinating sort of hierarchy of structure is getting bigger
7:49
Speaker 1: and bigger and bigger. And so I guess the question
7:51
Speaker 1: then is, you know, like what are globular clusters a
7:54
Speaker 1: cluster of Yes, what kind of pyramid scheme is a
7:58
Speaker 1: globular cluster. Who's the downstream and who's the upstream? Who's
8:04
Speaker 1: really making money off globular clusters? Right? Who's behind big
8:08
Speaker 1: globular taking globular clusters to the moon. So the answer
8:13
Speaker 1: is that globular clusters are clusters of stars. And to me,
8:17
Speaker 1: the fascinating thing is that there's something in between, sort
8:21
Speaker 1: of like our Solar system and the galaxy. Do you
8:24
Speaker 1: think about like our cosmic address. We're here on Earth,
8:28
Speaker 1: we're zooming around our star, and then we think that
8:30
Speaker 1: our star is just like one of many stars of
8:33
Speaker 1: hundreds of billions of stars in the galaxy. But it
8:37
Speaker 1: turns out that there's an intermediate step there. It's not
8:40
Speaker 1: like just Solar system and then galaxy. You could have
8:43
Speaker 1: organizations of solar systems. So when you zoom out, like
8:49
Speaker 1: when you see these videos of here you are on
8:52
Speaker 1: planet Earth. You're tiny and significant, flee like creature on
8:56
Speaker 1: this huge planet. Then you zoom out to Solar system
9:00
Speaker 1: and usually goes right from Solar system to galaxy. But no,
9:05
Speaker 1: there's an extra step. You're saying, there's an extra step. Yeah,
9:08
Speaker 1: some stars, some special stars grouped together into these big
9:13
Speaker 1: clusters of stars called globular clusters. Now, not every star
9:18
Speaker 1: is in one of these things. It's not like, you know,
9:20
Speaker 1: another layer in this hierarchy is sort of like a
9:23
Speaker 1: special clumping. Like most stars are just sort of like
9:26
Speaker 1: out there on their own, sort of like out in
9:28
Speaker 1: the middle of the countryside by themselves. But it turns
9:31
Speaker 1: out that there are these like urban areas where stars
9:34
Speaker 1: clump together really densely and make these things called globular clusters.
9:39
Speaker 1: And they're like a fascinating relic of the ancient formation
9:42
Speaker 1: of the galaxy and can tell us a lot about
9:44
Speaker 1: how things work out there. So it's like you've got
9:46
Speaker 1: a bowl of granola, and yet you have your little
9:49
Speaker 1: oatmeal pieces in there, but then you have the big
9:52
Speaker 1: clusters of oatmeal too. Those are the best ones. Those
9:57
Speaker 1: are the best ones. Those are nice. Yeah. I always
9:59
Speaker 1: fish those out first, and then I'm left with just
10:01
Speaker 1: sort of a bowl of sugary oatmeal and that's not great.
10:04
Speaker 1: But so that whole bowl is like the galaxy, but
10:07
Speaker 1: within that bowl you have the globular clusters of the
10:12
Speaker 1: nice crunch granola's. Yeah, exactly. The stars are not evenly
10:16
Speaker 1: distributed through the galaxy. I mean, the overall pattern is
10:19
Speaker 1: that there's more stars in the center of the galaxy
10:21
Speaker 1: with a gravity stronger, and then it's sort of peters
10:24
Speaker 1: out along the galactic disc. But inside there it's not smooth.
10:28
Speaker 1: There are these clumps where you get these big collections
10:31
Speaker 1: of stars. And we're not talking like, you know, five
10:34
Speaker 1: ten stars. We're talking like a few hundreds of thousands
10:37
Speaker 1: of stars. It's a big deal. Sounds like when they're
10:41
Speaker 1: making the galaxy that just didn't stir enough. That's what
10:43
Speaker 1: I learned about. Like when I'm trying to make polina,
10:45
Speaker 1: you know, it gets clumpy. You just didn't stir enough.
10:48
Speaker 1: Katie's globular polenda. That's not the foundation for your next
10:52
Speaker 1: food truck, right, And so these things have like a
10:55
Speaker 1: few hundred thousand stars in them, but they're not actually
10:58
Speaker 1: that big, right there only like ten to sometimes like
11:01
Speaker 1: three hundred light years wide. Okay, you say that's not
11:04
Speaker 1: that big. However, how long would it take me to
11:09
Speaker 1: drive from one end to the other of three hundred
11:12
Speaker 1: light years? Yeah, it would take you a while. I mean,
11:14
Speaker 1: even in your light speed polenta powered vehicle, it would
11:17
Speaker 1: take you three hundred years to go across three hundred
11:20
Speaker 1: light years obviously, and in a much slower, more reasonable
11:24
Speaker 1: ship it would take much much longer. But the reason
11:26
Speaker 1: I say that it's not that big is that there
11:28
Speaker 1: are so many stars in there. So would you end
11:31
Speaker 1: up with is stars in a very unusually dense collection
11:35
Speaker 1: like in our part of the galaxy in our neighborhood,
11:38
Speaker 1: there aren't that many stars, like the nearest stars more
11:40
Speaker 1: than four light years away, right, I mean, it seems
11:44
Speaker 1: like there would be conflict with stars being that close together, right,
11:49
Speaker 1: because I know every body in the universe has some
11:53
Speaker 1: kind of gravitational poll and stars are so big they
11:57
Speaker 1: seem like they would be acting on each other there,
12:00
Speaker 1: So it's it's odd that you would have them so
12:02
Speaker 1: close together. Yeah, And that's exactly what makes them fascinating
12:06
Speaker 1: because in these clusters we get to see stars doing
12:09
Speaker 1: something they don't normally do, which is like dance around
12:12
Speaker 1: each other and tug on each other and form new,
12:14
Speaker 1: weird kinds of stars. And we're gonna dig into all
12:17
Speaker 1: that crazy stuff that's happening inside the globular clusters in
12:20
Speaker 1: a minute. But here's some numbers for you, Like the
12:23
Speaker 1: density of stars in our neighborhood. Like around where we
12:26
Speaker 1: live in the galaxy is like one star per three
12:29
Speaker 1: hundred cubic light years, so that's pretty big area just
12:33
Speaker 1: to get one star. But inside one of these globular
12:35
Speaker 1: clusters there's like two stars per cubic light year, so
12:39
Speaker 1: it's like six hundred times denser than it is in
12:43
Speaker 1: our neighborhood. It's like going from the middle of nowhere
12:45
Speaker 1: to Manhattan. Really packed in there, like star deans. Yeah,
12:49
Speaker 1: they really are. Imagine what it would be like to
12:52
Speaker 1: live around a star in a globular cluster. You would
12:56
Speaker 1: have so many other like bright stars in the sky
12:59
Speaker 1: at night. The night itself might be a lot brighter
13:02
Speaker 1: than it is here. Yeah, it seems I would be
13:04
Speaker 1: as bright as daylight. You just have too many suns
13:08
Speaker 1: going on. Yeah, if you're near the center one of
13:10
Speaker 1: these things, I mean, the globular cluster itself is like
13:12
Speaker 1: twenty five thousand times brighter than the sun. These things
13:16
Speaker 1: are really bright. Some of them are up to like
13:18
Speaker 1: fifty times brighter than even that. You'd be in the
13:21
Speaker 1: middle of like a lot of light bulbs all the time.
13:24
Speaker 1: Maybe a pretty crazy experience. Well, I need to get
13:27
Speaker 1: some more high tech sunglasses. It seems like to be
13:30
Speaker 1: able to live here some of that those polarized shades.
13:35
Speaker 1: But before I do that, why don't we take a
13:37
Speaker 1: quick break and I will return with all new sunglasses.
13:52
Speaker 1: All right, I've got my super polarized super extra anti
13:56
Speaker 1: glare globular cluster sunglasses on. I can't see a thing indoors,
14:02
Speaker 1: but I think it'll help me see within the globular clusters. So,
14:06
Speaker 1: so what's going on around me? Yes, So these globular clusters.
14:09
Speaker 1: You have this big collection of stars all packed into
14:12
Speaker 1: one spot. And one of the amazing things is that
14:15
Speaker 1: there aren't actually that many of these, Like the galaxy
14:19
Speaker 1: has hundreds of billions of stars, but they're only about
14:22
Speaker 1: a hundred and fifty, maybe up to two hundred of
14:25
Speaker 1: these globular clusters. Well why are they so rare? We
14:29
Speaker 1: don't really understand, and we can talk in a minute
14:32
Speaker 1: about how they form, but one clue is that they're
14:34
Speaker 1: also not always contained within the galactic disk. Like when
14:39
Speaker 1: you look at the galaxy sort of from outside, which
14:42
Speaker 1: we can't do what we can look at other galaxies.
14:44
Speaker 1: Of course, you see that it's mostly a flat swirl,
14:46
Speaker 1: and that's because of how the galaxy formed. Right, the
14:49
Speaker 1: galaxy form from a huge collection of gas and dust
14:52
Speaker 1: which collapsed into stars and then gravity took over and
14:56
Speaker 1: try to pull all those stars together, and that's why
14:58
Speaker 1: you have a galaxy. But it's my it's harder for
15:00
Speaker 1: gravity to pull along the galactic plane because that's how
15:04
Speaker 1: the galaxy is spinning. That's spinning keeps things from falling
15:08
Speaker 1: in only along that plane. Perpendicular to that plane, you
15:11
Speaker 1: can squish it flat like a pancake. Is it sort
15:13
Speaker 1: of like when you have a bicycle wheel, You have
15:16
Speaker 1: some torque there, so you have that kind of like
15:19
Speaker 1: inward energy of the galaxy spinning, So it's easier for
15:24
Speaker 1: it to be flat and spinning inward than it is
15:26
Speaker 1: to spin another direction. Yeah, exactly, if you spin a
15:30
Speaker 1: bicycle wheel, then it's harder for things to sort of
15:33
Speaker 1: fall in towards the center. Or if you think, for example,
15:35
Speaker 1: about like a merry go round with ping pong balls
15:37
Speaker 1: on it, right you spin that thing, the ping pong
15:40
Speaker 1: balls are all going to fly out, but they're gonna
15:42
Speaker 1: fly out along that plane. So that's what we call
15:45
Speaker 1: rotation supported. The rotation of the galaxy is keeping things
15:48
Speaker 1: from falling inwards, but again only along that plane. There's
15:52
Speaker 1: nothing that prevents the collapse perpendicular to that plane, which
15:55
Speaker 1: is what makes it flat like a disk. Well, next
15:57
Speaker 1: time I go on a Merry go around, I'm bringing
15:59
Speaker 1: a bunch of ping pong balls with me. This is
16:02
Speaker 1: probably why I'm banned for most Merry go round. Maybe
16:05
Speaker 1: also because you try to eat polenta and you end
16:07
Speaker 1: up throwing up globular chunks of polenta. Oh man, When
16:12
Speaker 1: I was a kid, I was a throw upper kid,
16:15
Speaker 1: and I had some moments. I had my moments, especially
16:18
Speaker 1: on the teacups. All right, well, we don't want to
16:22
Speaker 1: revisit that with too much to jail. But the interesting
16:24
Speaker 1: thing about these globular clusters is that they don't tend
16:27
Speaker 1: to be along this galactic disk. Like if you looked
16:31
Speaker 1: at a diagram of where they are, there's some of
16:33
Speaker 1: them that are in the disc, but they're also sort
16:35
Speaker 1: of just spherically distributed around the galaxy. It's almost like
16:39
Speaker 1: they come from a time when the galaxy was a
16:42
Speaker 1: big puffy sphere before collapsed. Right, And I'm looking at
16:46
Speaker 1: this image and what it looks like to me is
16:49
Speaker 1: like a side view of like a fried egg, and
16:52
Speaker 1: then above it, like scattered around it are little little
16:56
Speaker 1: yellow dots like you just spilled a bunch of salts around. Man,
17:01
Speaker 1: I keep coming back to food on this globular cluster episode,
17:04
Speaker 1: don't I. We've gotta stop recording these at lunch. Whoever
17:08
Speaker 1: thought globular clusters would make you hungry? Like, I gotta
17:12
Speaker 1: bring a positive spin to it. So they're falling outside
17:16
Speaker 1: of that disk. You're saying that maybe these had formed
17:21
Speaker 1: back when the galaxy was sort of this big puppy cloud,
17:25
Speaker 1: and even as it flattened down to the disk, they
17:30
Speaker 1: didn't come with the rest of the game. Yeah, precisely.
17:33
Speaker 1: And there's a bigger topic here of the galaxies halo.
17:37
Speaker 1: Remember that galaxies are not mostly stars. Most of what's
17:41
Speaker 1: in the galaxies actually dark matter. And if you look
17:44
Speaker 1: at where the dark matter is in a galaxy, it
17:46
Speaker 1: doesn't collapse the same way that normal matter does. It
17:50
Speaker 1: tends to spin. And so this is big spherical halo
17:54
Speaker 1: of dark matter around the galaxy. And that's the original
17:57
Speaker 1: thing that's sort of like clustered together the gas of
18:00
Speaker 1: dust that made our galaxy. And so these globular clusters
18:03
Speaker 1: they're sort of in this larger galactic halo, but they
18:06
Speaker 1: haven't collapsed down into this disk, and we don't know
18:10
Speaker 1: exactly why. It could be that they didn't form with
18:13
Speaker 1: the original galaxy but are like their own little mini
18:17
Speaker 1: galaxies that were then captured later and that's why they're
18:20
Speaker 1: orbiting around. Or it could be that they formed with
18:23
Speaker 1: the rest of the galaxy but then didn't collapse as
18:26
Speaker 1: well as the gas and dust because they don't collide
18:29
Speaker 1: with each other as much as the gas clouds do,
18:31
Speaker 1: so they avoided like losing all that angular momentum and
18:35
Speaker 1: they can keep spinning around out there in crazy orbits.
18:38
Speaker 1: Or maybe they just prefer to hang out out in
18:41
Speaker 1: the dark matter halo. Dark Matter Halo is a really
18:44
Speaker 1: good metal band name, I've got to say. Yeah, So
18:47
Speaker 1: that that's interesting. We can't see dark matter, but it
18:50
Speaker 1: is there, and so it's like this halo around the
18:56
Speaker 1: galactic disc. And suspended in that halo are these little
19:00
Speaker 1: dots and those are each a globular cluster, yeah, exactly,
19:05
Speaker 1: and some of them happen to fall within the galactic disc,
19:08
Speaker 1: but most of them do not. You know. The closest
19:11
Speaker 1: one to us is about sixteen thousand light years away.
19:15
Speaker 1: It's called the Omega cluster. But there's a bunch of
19:17
Speaker 1: these things, and what's really interesting is how they form.
19:21
Speaker 1: And as you said earlier, they might tell us something
19:23
Speaker 1: about the age of the Milky Way, because we think
19:27
Speaker 1: that they formed very very early on as the galaxy
19:30
Speaker 1: was forming. You know, the way these things happened is
19:32
Speaker 1: that you get, you know, a big clump of gas
19:34
Speaker 1: and dust, and it may have been that you just
19:36
Speaker 1: got sort of like an over dense pocket of gas
19:39
Speaker 1: and dust something which was like, you know, got more
19:41
Speaker 1: of a serbing of globs than the rest of the
19:43
Speaker 1: stuff around it, and it collapsed all at once and
19:46
Speaker 1: made a big bunch of stars. And so these globular clusters,
19:50
Speaker 1: when we look at them, we see a bunch of
19:51
Speaker 1: stars and no gas and dust in between, which means
19:55
Speaker 1: like they're not forming any new stars. So there's sort
19:57
Speaker 1: of like a little time capsule from very very early
20:01
Speaker 1: formation of the galaxy. So when you say it happens
20:03
Speaker 1: at the same time, what are we talking about, Like
20:07
Speaker 1: it all happens within sort of one of our human
20:10
Speaker 1: years or is it literally like within a few moments?
20:14
Speaker 1: Oh wow, now we're talking like in within millions of years. Okay,
20:17
Speaker 1: star times. We humans are sort of like dogs. We
20:22
Speaker 1: live in dog years and they live in star years. Yeah,
20:25
Speaker 1: they live in star years. We think that these globular
20:28
Speaker 1: clusters are about eleven to thirteen billion years old. I remember,
20:33
Speaker 1: the whole universe is only just under fourteen billion years old,
20:37
Speaker 1: which makes these things some of the oldest things in
20:40
Speaker 1: the galaxy, which is how we can sort of use
20:42
Speaker 1: them to help understand the age of the galaxy. And
20:45
Speaker 1: also when we see them in other galaxies like Andromeda,
20:48
Speaker 1: we can use them to help understand the age of Andromeda.
20:51
Speaker 1: And one way we can do that is because we
20:53
Speaker 1: think that all the stars in there were formed at
20:56
Speaker 1: the same time, which means they all sort of like
20:59
Speaker 1: start their own clock at the same time. And you
21:01
Speaker 1: remember that the life cycle of a star is that
21:04
Speaker 1: it burns for a while and then ones is done
21:06
Speaker 1: with all of its fuel. It either goes nova or
21:09
Speaker 1: collapses or something. But the lifespan there depends on the
21:12
Speaker 1: original size of the star. The more mass it has,
21:15
Speaker 1: the faster it burns. The smaller it is, the longer
21:18
Speaker 1: it burns. So we can tell something about the age
21:21
Speaker 1: of these things just by looking at like the distribution
21:23
Speaker 1: of stars, which ones have burned out already, which ones
21:25
Speaker 1: have not. But the fact that they've all formed at
21:28
Speaker 1: the same time makes it very easy to sort of
21:30
Speaker 1: like reverse that back and understand how this thing started.
21:33
Speaker 1: It's nice from a scientific perspective because you control for
21:37
Speaker 1: the factor of age. You've got like these little test
21:40
Speaker 1: tubes out there that you can look at as physicists. Yeah, exactly.
21:44
Speaker 1: And they're also an interesting collection of stars because they're
21:47
Speaker 1: not stars like our sun. Our universe has gone through
21:51
Speaker 1: a few cycles of making stars. You know, the very
21:54
Speaker 1: early universe, you had hydrogen helium and that fell together
21:57
Speaker 1: to make the original first generation of ours, which weirdly
22:01
Speaker 1: astronomers called population three stars. And those were really big
22:06
Speaker 1: and didn't burn for very long, but they made some
22:08
Speaker 1: like helium and some heavier stuff and things that astronomers
22:11
Speaker 1: called metals. And then when they blew up and they
22:14
Speaker 1: spread their stuff through the galaxy, there was a second
22:16
Speaker 1: generation of stars which formed, and those are called population
22:20
Speaker 1: two stars. Some of those burned up and collapsed and
22:23
Speaker 1: spread their stuff through the galaxy to make population three stars,
22:26
Speaker 1: which is like our sun is a population three stars.
22:30
Speaker 1: But these stars in the globular clusters are only population
22:33
Speaker 1: two stars. There weren't any of the population one stars,
22:36
Speaker 1: the ones like our sun when these things formed. So
22:40
Speaker 1: you may have explained this. It counts down. It goes
22:42
Speaker 1: pop three pop to pop one is the newest or yeah, exactly,
22:46
Speaker 1: which I guess makes the next generation of stars are
22:49
Speaker 1: gonna be what pop zero and then pop negative one?
22:52
Speaker 1: Like nobody really thought this through pop zoomers. And the
22:56
Speaker 1: other fun thing about these is that that very low metallicity,
23:00
Speaker 1: Like there's basically just helium and hydrogen because that's what
23:04
Speaker 1: was around after the first generation of stars, the population
23:07
Speaker 1: three stars. You know, astronomers have this weird naming system
23:10
Speaker 1: for basically everything. Well one thing that's especially weird is
23:13
Speaker 1: what they call them metal. Like everything that's not hydrogen
23:16
Speaker 1: or helium is a metal to them because it's like
23:18
Speaker 1: a big heavy element. See. I mean, like, you know,
23:21
Speaker 1: there's a lot of controversy in the metal community of
23:24
Speaker 1: what can be considered metal. There's prog metal, and some
23:27
Speaker 1: people say, no, it's too much of a ballad to
23:29
Speaker 1: be metal, But you know, I think it's nice to
23:33
Speaker 1: be inclusive, and so these globular clusters that have basically
23:36
Speaker 1: only very low metal stars. And these stars are also
23:40
Speaker 1: not that big, which is why they've been burning for
23:42
Speaker 1: so long, and they might continue to burn for billions
23:45
Speaker 1: and billions of years more. The smaller kinds of stars,
23:47
Speaker 1: like red dwarves, they might even last for trillions of years.
23:50
Speaker 1: So these are very I guess gassy stars would be
23:54
Speaker 1: fair to say these sorry gassy stars. But the interesting
23:57
Speaker 1: thing is that they've sort of cleared out all the
24:00
Speaker 1: ask the dust inside of them. They're not making any
24:02
Speaker 1: new stars. Other parts of our galaxy still have these
24:05
Speaker 1: big blobs of gas and dust, so there's still new
24:08
Speaker 1: stars being made all the time, Like our son was made,
24:11
Speaker 1: you know, fairly recently on these time scales, only five
24:14
Speaker 1: billion years ago. But the globular clusters, they're sort of
24:16
Speaker 1: like you know, old boys clubs. They made all their stars,
24:19
Speaker 1: they used up all their gas and dust, and then
24:21
Speaker 1: they're done. They're just like, we're gonna hang out. We're
24:24
Speaker 1: happy with a number of stars. We have no new members. Typical. Typical.
24:29
Speaker 1: There are some places in the universe where globular clusters
24:32
Speaker 1: are still forming, like in the large Magellanic Cloud there's
24:36
Speaker 1: a big positive gas and people think that it's now
24:39
Speaker 1: forming into a new globular cluster. And by now we mean,
24:42
Speaker 1: you know, within the last twenty million years on star time,
24:45
Speaker 1: star time, not not a little human dog time. But
24:49
Speaker 1: there's still a lot of really interesting mysteries about these things.
24:52
Speaker 1: Most of them have sort of like a single population
24:55
Speaker 1: of stars that we think all formed at the same time,
24:57
Speaker 1: and you can tell based on like the star ages
24:59
Speaker 1: and sort of how they're like popping off and dying.
25:02
Speaker 1: But some of them have like two or three different populations.
25:05
Speaker 1: It looks like there was a clump all made it once,
25:08
Speaker 1: and then another clump all made at the same time
25:10
Speaker 1: that was different from the first clump. So there's a
25:12
Speaker 1: lot of interesting mysteries there. So is it more rare
25:15
Speaker 1: for globular clusters to form in our current universe than
25:20
Speaker 1: you think that it was like near the beginning of
25:22
Speaker 1: the universe. Yeah, absolutely, because a lot of the gas
25:26
Speaker 1: has already turned into stars or into globular clusters, and
25:29
Speaker 1: so it's very rare for globular clusters to still be made.
25:32
Speaker 1: Most of them were made in the early universe and
25:34
Speaker 1: they're just sort of like hanging around. They're like, you know,
25:36
Speaker 1: the old folks still smoking in the back of a bar,
25:39
Speaker 1: you know, and they're just not really making them like
25:41
Speaker 1: they used to anymore. There's just not enough gas to
25:43
Speaker 1: go around, which I can't believe I'm saying. And so
25:47
Speaker 1: we don't really understand like how these globular clusters have
25:50
Speaker 1: multiple different populations, Like people think maybe different globular clusters
25:55
Speaker 1: might have merged, like you had two of them formed
25:57
Speaker 1: at different times, and they sort of came to get
26:00
Speaker 1: there to make one that had two different populations in it.
26:02
Speaker 1: But it's you know, it's an area of active research.
26:04
Speaker 1: It's not something we really understand. So could I live
26:08
Speaker 1: in a globular clusters? What's going on in there? Is it?
26:13
Speaker 1: Is there anywhere for me to be? Are you looking
26:16
Speaker 1: to move, Katie? You are happy with your current apartment.
26:19
Speaker 1: I've got my cool shades that I currently can't say
26:22
Speaker 1: anything through, So I've gotta gotta find a place as
26:24
Speaker 1: bright as I am. It's a really fun question because
26:28
Speaker 1: it's fun to imagine what would like to be on
26:31
Speaker 1: a planet inside a globular cluster, And so people are wondering,
26:34
Speaker 1: like are there planets around these stars? Do these stars
26:38
Speaker 1: also have like planetary disks which collapse and give you
26:42
Speaker 1: rocky stuff that you could live on. Could there be
26:44
Speaker 1: alien life that evolved inside a globular cluster? We think
26:48
Speaker 1: actually it's pretty unlikely for these things to have planets
26:51
Speaker 1: around them, which is a bit disappointing when it comes
26:53
Speaker 1: to like writing science fiction novel about it. But there's
26:56
Speaker 1: really two reasons. One is that most of the material
26:59
Speaker 1: just sort of went to making stars, Like there's mostly
27:03
Speaker 1: gas there, so it's hard to form planets. Planets you
27:06
Speaker 1: tend to want to have like a rocky core with
27:09
Speaker 1: something heavy in it, But these things formed in the
27:11
Speaker 1: early universe when there was basically just hydrogen and helium
27:14
Speaker 1: and very small amounts of heavier stuff, so you didn't
27:17
Speaker 1: have sort of the raw ingredients to make planets. And
27:19
Speaker 1: the second is that it's pretty hard for a planet
27:22
Speaker 1: to stay orbiting a star if there are so many
27:26
Speaker 1: other stars nearby constantly tugging on it. Right, it seems
27:29
Speaker 1: like even if you could have like a gas planet,
27:33
Speaker 1: it would just get ripped apart by these quarreling stars. Yeah, exactly,
27:39
Speaker 1: and it would just get tugged out of orbit. You know,
27:41
Speaker 1: we think of our planet is mostly just orbiting the Sun,
27:45
Speaker 1: but there are gravitational forces from other nearby stars or
27:49
Speaker 1: things that pass nearby, and when the Sun comes nearby
27:52
Speaker 1: other stars, those things get stronger. So in a globular cluster,
27:56
Speaker 1: remember it's much much denser, there are many more stars,
28:00
Speaker 1: your byes of these tugs are a lot stronger. So
28:02
Speaker 1: even if you did form a planet and it did
28:04
Speaker 1: survive being pulled apart, as you said, you woul probably
28:07
Speaker 1: just get like passed around from star to star. Wouldn't
28:10
Speaker 1: have like a stable orbit like a volleyball exactly like
28:14
Speaker 1: a hot potato planet. That doesn't sound ideal for me
28:19
Speaker 1: as a little person living on this volleyball planet. So
28:22
Speaker 1: I'm gonna have to rethink my travel plans. So we'll
28:27
Speaker 1: take a break while I look into real estate in
28:30
Speaker 1: a different part of the universe. Alright, so we are back.
28:45
Speaker 1: I am looking at man Zillo just does not really
28:50
Speaker 1: go into like beetle juice area. There aren't very many
28:56
Speaker 1: sales to track there, so who knows how much of
28:58
Speaker 1: those houses cost. So we're talking about globular clusters. We
29:04
Speaker 1: have found out that I cannot live there inside a
29:07
Speaker 1: globular cluster, dream shattered but maybe there's something else we
29:11
Speaker 1: can get out of these globular clusters. Yeah, we think
29:15
Speaker 1: that there aren't planets around these things. And people actually
29:18
Speaker 1: went and looked and they studied a cluster and one
29:21
Speaker 1: of them had exactly zero planets in them. And then
29:24
Speaker 1: they looked at another cluster and they actually did find
29:26
Speaker 1: one planets, this huge Jupiter sized planet. But it's orbiting
29:31
Speaker 1: a pulsar in a binary star system. It's like a
29:34
Speaker 1: really rare and unusual kind of situation. And a pulsar
29:37
Speaker 1: is not what you want for like your home sun.
29:40
Speaker 1: So what is a pulsar? A pulsar is a star
29:43
Speaker 1: that's already collapsed, so it's burned it through its life
29:46
Speaker 1: and it doesn't have the energy to prevent gravitational collapse,
29:50
Speaker 1: and so it falls down into a neutron star and
29:52
Speaker 1: then it starts spinning crazily and emitting crazy radiation into
29:56
Speaker 1: the universe, which then sweeps across the sky and pulses,
29:59
Speaker 1: which why we call it a pulsar. We have a
30:01
Speaker 1: whole fun podcast episode about pulsars people can dig into.
30:05
Speaker 1: But pulsars don't emit light the same way like our
30:08
Speaker 1: son does because there's no fusion going on inside, so
30:11
Speaker 1: it would be a pretty chilly place to live. Well,
30:15
Speaker 1: I'll pack a sweater, pack all the sweaters. But there
30:20
Speaker 1: are some really interesting things you can do with globular clusters,
30:24
Speaker 1: like experiments, you can do questions, you can ask things,
30:27
Speaker 1: you can learn about the universe. To me, what's really
30:29
Speaker 1: interesting is that you get all these stars together, like
30:32
Speaker 1: really tightly packed, and so you get to see like
30:34
Speaker 1: what happens when stars get really dense, when they're like
30:37
Speaker 1: all tugging on each other gravitationally. Because you know, normally
30:40
Speaker 1: stars are pretty far separated, they don't really pull on
30:44
Speaker 1: each other that much. So it's like getting to study
30:46
Speaker 1: what happens when they get all crammed together. It's a
30:49
Speaker 1: starsh pit exactly. You get really interesting dynamics. Like some
30:55
Speaker 1: of these things have had what they call core collapse,
30:58
Speaker 1: where the center of the globe the cluster has a
31:00
Speaker 1: bunch of really really big stars and all the smaller
31:03
Speaker 1: stars are on the outside. And so they're trying to
31:05
Speaker 1: understand like are these because of gravitational interactions where like
31:09
Speaker 1: two stars come near each other and then sort of
31:11
Speaker 1: like throw each other in different directions and the bigger
31:13
Speaker 1: star always gets sort of thrown a little bit more
31:16
Speaker 1: towards the center, so that after billions of years, you
31:19
Speaker 1: end up with the smaller ones like in a little
31:21
Speaker 1: halo around the bigger ones at the center. It's like
31:24
Speaker 1: you have a bunch of dance partners, and you've got
31:27
Speaker 1: a bunch of little guys and some some big guys,
31:30
Speaker 1: and they're doing the dance from you know, the Titanic,
31:32
Speaker 1: where you hold hands and you spin around in a
31:34
Speaker 1: circle and then you let the other person go and
31:36
Speaker 1: they go flying. But it's a bunch of stars, and
31:38
Speaker 1: so maybe the little ones, like when they go flying,
31:42
Speaker 1: they fly out further, keep getting slingshotted out to the outside,
31:47
Speaker 1: whereas the bigger ones don't get tossed or heated. As
31:51
Speaker 1: the kids say as far, Yeah, that's exactly what happens.
31:54
Speaker 1: That makes the core of these things even crazier, because
31:57
Speaker 1: not only is it a place where there are a
31:59
Speaker 1: lot of stars, but now you have even bigger stars
32:01
Speaker 1: all clustered towards the center. So the heart of these
32:05
Speaker 1: globular clusters must be a really crazy place to live
32:08
Speaker 1: or even to visit. It seems slightly deadly. Potentially, you
32:13
Speaker 1: can also see really interesting new kinds of stars. There's
32:16
Speaker 1: a kind of star that seems to only exist inside
32:19
Speaker 1: a globular cluster. Yeah, and these actually I gotta give
32:23
Speaker 1: astronomers kudos because they have a cool name. These stars
32:25
Speaker 1: are called blue stragglers. Oh man, this sounds like I
32:30
Speaker 1: can just hear sort of like a guitar toWin going
32:33
Speaker 1: on and a country songs starting about the blue stragglers. Yeah,
32:40
Speaker 1: they lost their dog and their truck. But the interesting
32:44
Speaker 1: thing about these stars is that usually what happens to
32:47
Speaker 1: a star is a d percent determined by how much
32:50
Speaker 1: gas it started with and then how old it is.
32:52
Speaker 1: So you start with a bunch of gas and it
32:54
Speaker 1: burns for a long time, and you know, it's color
32:56
Speaker 1: depends on its temperature, which depends on the gravitation pressure,
33:00
Speaker 1: which depends again on just how much stuff it is.
33:03
Speaker 1: So you get enough stuff, you're gonna have a red giant.
33:05
Speaker 1: You get a little more, you can have a blue giant,
33:07
Speaker 1: for example. And so it's a very like well known,
33:10
Speaker 1: well understood sequence and stars should only appear like somewhere
33:14
Speaker 1: on this curve that tells you the mass and the
33:16
Speaker 1: age of the star. But inside these globular clusters is
33:19
Speaker 1: a weird kind of star called a blue straggler, and
33:22
Speaker 1: they're much bluer than you expect for a star of
33:26
Speaker 1: that size and that age. Poor things they got the
33:31
Speaker 1: blues that country music at all. It's the blues really,
33:35
Speaker 1: all right, So why are they so down? Are you
33:36
Speaker 1: talking about the color? Yeah, well, we don't exactly know.
33:39
Speaker 1: It's a fascinating area of study, something people are trying
33:43
Speaker 1: to understand. And that's what's really interesting about these globular clusters.
33:46
Speaker 1: It's like a new experiment. You know. Astrophysicists, they don't
33:49
Speaker 1: get to do experiments like particle physicists, where we like
33:52
Speaker 1: smash stuff together to see what happens. They don't just
33:55
Speaker 1: say I'm going to smash two stars together and see
33:57
Speaker 1: what happens. We don't have a star canon yet, we
34:00
Speaker 1: can't do it, yeah, exactly. We asked for funding for
34:02
Speaker 1: the Star game seventy two trillion dollars, but we haven't
34:05
Speaker 1: heard back yet. But what they can do is just
34:07
Speaker 1: sort of look out into the universe and see if
34:10
Speaker 1: these experiments are already happening. Because the universe is chalk
34:13
Speaker 1: filled with weird stuff, and if you look long enough,
34:16
Speaker 1: you'll see something that might answer your science question. And
34:19
Speaker 1: so we think that might be what's happening inside globular clusters,
34:23
Speaker 1: that essentially star collisions happened. That the reason these stars
34:27
Speaker 1: are like two or three times bigger than you expect
34:30
Speaker 1: for a blue star is that they sort of like
34:32
Speaker 1: got captured and fell together and formed an extra big star.
34:37
Speaker 1: So they just kind of like it's a collision and
34:39
Speaker 1: instead of all spreading out, it all kind of just
34:42
Speaker 1: starts to I hate to say it, but congealed together,
34:47
Speaker 1: coagulated exactly. And you know, that tells us something about
34:50
Speaker 1: star formation, because most stars we see formed outside globular clusters,
34:54
Speaker 1: and that tells us about the distribution. You know, you
34:56
Speaker 1: get a certain amount of helium and hydrogen, you get
34:59
Speaker 1: this kind of star of that kind of star. This
35:01
Speaker 1: tells us that under special circumstances, if you make a
35:04
Speaker 1: bunch of big stars near each other, they can combine
35:06
Speaker 1: together to make a super kind of star blue straggler
35:10
Speaker 1: that doesn't appear anywhere else in the galaxy or the universe.
35:13
Speaker 1: It's like a special star laboratory. And what's the straggler
35:18
Speaker 1: part of the name referring to if you look at
35:20
Speaker 1: the curve for where stars are, it's like color versus mass.
35:25
Speaker 1: Then there's this population of blue stragglers that are sort
35:28
Speaker 1: of off the curve. They're like to the left, and
35:31
Speaker 1: so they're sort of like not hanging out with the
35:33
Speaker 1: rest of them that are like falling behind. You know,
35:35
Speaker 1: you don't want to judge these stars and make them
35:37
Speaker 1: feel bad. They're just sort of different. They're differently starred. Yeah,
35:41
Speaker 1: they're differently started exactly. Globular clusters also give us a
35:45
Speaker 1: laboratory for trying to understand another mystery of the universe,
35:49
Speaker 1: and that has to do with black holes. Black holes
35:52
Speaker 1: form in our universe, but sort of only in two
35:54
Speaker 1: different groups. Like we either get black holes that form
35:57
Speaker 1: when stars collapse, and then they're about the mass of
36:00
Speaker 1: a star. And so we see black holes from stellar
36:02
Speaker 1: collapse and they're out there and they have masses of
36:04
Speaker 1: like ten to a hundred times the mass of our Sun,
36:08
Speaker 1: about what you would expect from the collapse of massive stars.
36:10
Speaker 1: Then there's another whole group of black holes that are
36:13
Speaker 1: like millions of solar masses, and these are the ones
36:16
Speaker 1: at the centers of galaxies. So you got like stellar
36:19
Speaker 1: black holes hanging out in the neighborhood, and then like
36:21
Speaker 1: the really big Papa black holes in the centers of galaxies.
36:25
Speaker 1: And one question in astrophysics for a long time is
36:28
Speaker 1: like where are the intermediate ones? Like why are there
36:31
Speaker 1: no black holes that are sort of like between a
36:33
Speaker 1: hundred and ten thousand solar masses right the Goldilocks black holes? Yeah,
36:38
Speaker 1: you know, why don't black holes emerge to form the
36:41
Speaker 1: bigger ones. It's an interesting question about like where they're
36:44
Speaker 1: made and how often it happens, and so this is
36:46
Speaker 1: something people have been trying to understand. And one possibilities
36:50
Speaker 1: that you might be able to make intermediate mass black
36:52
Speaker 1: holes in globular clusters because here you have like an
36:56
Speaker 1: unusual density of stars and if a bunch of them
36:59
Speaker 1: go black hole and then formed together, you might be
37:01
Speaker 1: able to make one of these things. So how are
37:04
Speaker 1: we going to do this? What do we need to
37:05
Speaker 1: make a black hole out of one of these globular clusters. Well,
37:09
Speaker 1: we don't have to do much. We just sort of
37:11
Speaker 1: sit back like astronomers and look out in the universe
37:14
Speaker 1: that's putting on a show for us. And the idea
37:17
Speaker 1: is sort of wait for one of these things to
37:19
Speaker 1: turn into a black hole. And then if there are
37:21
Speaker 1: a bunch of other black holes nearby, they could sort
37:23
Speaker 1: of swirl into each other. And remember what happens when
37:26
Speaker 1: you toss a black hole into a black hole is
37:29
Speaker 1: you just get a bigger black hole. Right, black holes
37:32
Speaker 1: don't like tear each other apart. Anything you tossed into
37:35
Speaker 1: a black hole just makes a black hole bigger. This
37:38
Speaker 1: is one of the favorite things people write in about,
37:40
Speaker 1: like what if I threw in, you know, antimatter into
37:43
Speaker 1: a black hole? Or what if I shot a laser
37:45
Speaker 1: into a black hole? Right? You can't destroy a black
37:47
Speaker 1: hole by adding more energy to it. A black hole
37:50
Speaker 1: is just a big blob of dense energy. So the
37:53
Speaker 1: more you add to it, the more black holely it gets.
37:55
Speaker 1: This is called the Kirby principle. Is at a cartooning joke.
38:01
Speaker 1: It's a it's a Nintendo character Kirby. He just sucks
38:04
Speaker 1: stuff up and he gets bigger and bigger. Awesome. Well,
38:09
Speaker 1: that's exactly what happens. And so black holes can eat
38:12
Speaker 1: other black holes and then become super black holes. Or
38:16
Speaker 1: if you start out with a bunch of smaller ones,
38:18
Speaker 1: you might get an intermediate mass black hole, and that'd
38:21
Speaker 1: be really interesting because maybe intermediate glass black holes do
38:24
Speaker 1: something different from the really big ones. Are the really
38:26
Speaker 1: little ones, you know, the really big ones are for example,
38:29
Speaker 1: sometimes their quasars they make crazy radiation because of all
38:33
Speaker 1: the gas and dust swirling around them. So this would
38:35
Speaker 1: be like a cool opportunity to just see something new
38:38
Speaker 1: we've never seen before. And so people are looking inside
38:41
Speaker 1: these globular clusters trying to see if there are these
38:44
Speaker 1: intermediate mass black holes inside of them. So when you're
38:47
Speaker 1: looking in a globular clusters, there a trick to being
38:50
Speaker 1: able to find a black hole inside one of these. Yeah,
38:53
Speaker 1: that's great question because you can't obviously see them directly.
38:56
Speaker 1: The way you can see a black hole is either
38:59
Speaker 1: gravitational lensing of the stuff behind it. So for example,
39:02
Speaker 1: of a star passes behind the black hole, than most
39:05
Speaker 1: of the star would disappear or some of the light
39:07
Speaker 1: from the star would bend around the black hole and
39:10
Speaker 1: you could see that sort of distortion. And actually a
39:12
Speaker 1: globular cluster is a great place to do that because
39:15
Speaker 1: you have a lot of stars moving all around, so
39:17
Speaker 1: it's easier to see this gravitational lensing effect I see.
39:21
Speaker 1: So the more activity you have, like, the easier it
39:24
Speaker 1: is to see the disruption of that activity as done
39:28
Speaker 1: by the black hole. Yeah, because you can see the
39:31
Speaker 1: black hole directly, you can only see its influence on
39:33
Speaker 1: stuff around it. So you can either see it bending
39:36
Speaker 1: the light that comes from behind it, or you could
39:39
Speaker 1: just see its gravitational effects on the nearby stars. Like
39:42
Speaker 1: the black hole that's at the center of our galaxy.
39:45
Speaker 1: We know it's there because we've seen its pull on
39:47
Speaker 1: the stars that are around and we see those stars
39:50
Speaker 1: orbiting something that isn't there but obviously has a very
39:53
Speaker 1: strong gravitational pull. And so globular clusters are a great
39:56
Speaker 1: way to see black holes because there are so many
39:59
Speaker 1: of these gravitation or probes. If there's a black hole somewhere,
40:02
Speaker 1: you should be able to see its effect on the
40:04
Speaker 1: nearby stars. You can calculate, like how should these stars
40:07
Speaker 1: be moving if there wasn't the black hole, And then
40:09
Speaker 1: you can see if there's a deviation from what you
40:11
Speaker 1: expect and if that could be explained by putting an
40:14
Speaker 1: invisible heavy mass in one spot, and if so, then
40:17
Speaker 1: you think you've seen one. So have we found any
40:19
Speaker 1: inside a globular cluster. So no confirmed sightings of intermedium
40:23
Speaker 1: mass black holes and globular clusters. I know, stay tuned.
40:27
Speaker 1: There was one where people thought maybe they saw one
40:30
Speaker 1: with four thousand solar masses, but then follow up analysis
40:33
Speaker 1: didn't see the same results. And actually you could explain
40:36
Speaker 1: all of the star paths without the black hole. And
40:39
Speaker 1: so it's a hard thing to do because these things
40:41
Speaker 1: are not that close by, and you're looking at individual
40:43
Speaker 1: stars in a cluster, you know, thousands of light years away.
40:47
Speaker 1: But it's an exciting thing. It's a it's a cool
40:49
Speaker 1: new object for us to look into and to ask
40:52
Speaker 1: questions about the way stars form and new weird kinds
40:55
Speaker 1: of stars and strange conditions for black holes. I mean,
40:59
Speaker 1: it seems like a real, just fun happening spot in
41:02
Speaker 1: the universe to really put your papers on. As an astronomer. Yeah,
41:06
Speaker 1: I think it's really interesting and I love these bits
41:09
Speaker 1: of the universe that are sort of left over from
41:11
Speaker 1: an earlier time. Now, these things formed more than ten
41:15
Speaker 1: billion years ago and they're still around, which gives us
41:18
Speaker 1: an opportunity to learn, like what was going on back then,
41:21
Speaker 1: because what happened back then is what determined the shape
41:24
Speaker 1: and the nature and the content of these things. So
41:26
Speaker 1: they really are like a little time capsule of the
41:29
Speaker 1: early universe. And everything we're doing in physics about trying
41:32
Speaker 1: to understand the universe is about trying to rewind and
41:35
Speaker 1: trying to understand how did everything happen. So to do
41:38
Speaker 1: that we have to find clues. We have to look
41:40
Speaker 1: for places in the universe where stuff is left over.
41:43
Speaker 1: You now, this is like the astrophysics analogy of a fossil,
41:47
Speaker 1: you know, a little piece of evidence left over from
41:49
Speaker 1: an earlier time, or like a living fossil, like a
41:52
Speaker 1: Ceila camp. Yeah, exactly, like a living fossil. Unfortunately, there
41:56
Speaker 1: probably aren't any aliens living on planets swinging arounds from
42:00
Speaker 1: star to star inside a globular cluster. But maybe there are,
42:04
Speaker 1: and if so, maybe they could tell us something fascinating
42:06
Speaker 1: about what it's like to live inside such a bright environment.
42:09
Speaker 1: I'm hoping to find a blob fish inside a globular cluster.
42:14
Speaker 1: I think that's why globular cluster sounds gross to me,
42:17
Speaker 1: because it resonates with the word blob. You know, every
42:20
Speaker 1: time on this podcast, I wanted to say globular cluster
42:23
Speaker 1: of almost said blobular cluster. Well, you know it's interesting
42:27
Speaker 1: because globular clusters do not deserve that kind of nasty name. Likewise,
42:33
Speaker 1: the blobfish actually gets a bad reputation. It does not
42:37
Speaker 1: look like that. Have you ever seen the blobfish. It
42:40
Speaker 1: looks sort of like a a sad, ziggy exploded blob
42:45
Speaker 1: with a frown. Yes, it's not very advertising. No, no,
42:49
Speaker 1: it looks like a slimy bloble. That's because it exploded
42:52
Speaker 1: when you brought it up from the deep sea and
42:54
Speaker 1: it's natural environment. I wouldn't say it's a looker. It's
42:57
Speaker 1: not beautiful, but it it looks a lot more solid.
43:01
Speaker 1: It just kind of looks like this gray, sort of solid,
43:04
Speaker 1: bony fish. But when you bring it to the surface,
43:06
Speaker 1: it looks like a blob. And so you know you
43:08
Speaker 1: can't trust a glob or a blob by the name. Well,
43:13
Speaker 1: it must be very disappointed. You know. It looked at
43:15
Speaker 1: itself in the mirror before it leads the house, and
43:17
Speaker 1: it's like, I'm looking good, and then it ends up
43:19
Speaker 1: looking like a big blob when it's brought up to
43:21
Speaker 1: the surface. And they truly do look quite pathetic because
43:24
Speaker 1: it looks like they're frowning. But maybe the globular clusters
43:29
Speaker 1: and the blobfish can come together and get some better
43:32
Speaker 1: pr for themselves. Maybe the aliens that live in globular
43:36
Speaker 1: clusters look like blob fish and they'll come here and
43:39
Speaker 1: they'll recognize the blobfish as you know, really the people
43:43
Speaker 1: they want to talk to. It seems like you'd have
43:45
Speaker 1: to be sort of blobular to live in a globular
43:48
Speaker 1: cluster because of all those stars tugging on you all
43:50
Speaker 1: the time. Like Taffy, your planet would be a bit
43:53
Speaker 1: of a blob as well. All right, well, thanks everyone
43:56
Speaker 1: for sharing your curiosity with us and taking this tour
43:58
Speaker 1: of a fascinating structure inside our galaxy, something that can
44:02
Speaker 1: tell us all about the universe and house stars formed
44:05
Speaker 1: in the age of our galaxy, and maybe about the
44:08
Speaker 1: future of black holes. Episode. When someone says, hey, would
44:11
Speaker 1: you like a globular cluster, don't turn your nose up
44:14
Speaker 1: at it. It could teach you about the deepest secrets
44:16
Speaker 1: of the universe. But please don't use that for your
44:19
Speaker 1: next breakfast cereal. All right, everyone, thanks for tuning in,
44:23
Speaker 1: see you next time. Thanks for listening, and remember that
44:33
Speaker 1: Daniel and Jorge explained. The Universe is a production of
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44:40
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