Latest / Daniel and Kelly’s Extraordinary Universe / How do planets get rings?

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How do planets get rings? · Daniel and Kelly’s Extraordinary Universe

• 0:08
  Speaker 1: Pee Katie, help me out with some research for an
• 0:10
  Speaker 1: upcoming episode. Alright, as long as you don't put me
• 0:13
  Speaker 1: in that collider of yours. Not this time, but you know,
• 0:16
  Speaker 1: in general, no promises, so just make sure you always
• 0:19
  Speaker 1: read the waiver very carefully. All right, I'll wear a helmet.
• 0:23
  Speaker 1: So what are we researching? Well, I'm trying to understand rings,
• 0:27
  Speaker 1: all right, and how can I help? Well, you got
• 0:30
  Speaker 1: engaged and married recently, didn't you. Yeah, during the pandemic.
• 0:34
  Speaker 1: I had a zoom wedding. It was It was really fun.
• 0:38
  Speaker 1: And did you get a real ring or a digital
• 0:40
  Speaker 1: zoom ring? I got a real ring, not just an
• 0:44
  Speaker 1: n f T pointing tour ring. Yes, I have a
• 0:46
  Speaker 1: real ring. And tell us a little bit about it.
• 0:49
  Speaker 1: Is it made out of icy particles or mostly dust
• 0:52
  Speaker 1: and rocks. It was actually grown in a lab lab
• 0:55
  Speaker 1: grown diamonds, which is pretty neat to me. Well, I
• 0:58
  Speaker 1: wonder if castor and planetary rings have anything in common. Yeah,
• 1:03
  Speaker 1: I wonder the same thing. You know. Actually, my husband
• 1:07
  Speaker 1: later told me that he had the choice to get
• 1:10
  Speaker 1: like a ring made out of a meteorite, So sometimes
• 1:14
  Speaker 1: they do converge. While it'd be awesome a little bit
• 1:16
  Speaker 1: of space on your finger. Well, we will have to
• 1:22
  Speaker 1: invite Saturn on the podcast to ask how it got
• 1:25
  Speaker 1: its rings and when it's fiance proposed to it. Saturn's
• 1:30
  Speaker 1: got the best bling in the Solar system. Hi, I'm Daniel.
• 1:49
  Speaker 1: I'm a physicist at UC Irvine and I do research
• 1:52
  Speaker 1: at the Large Hadron Collider. I am Katie Golden. I
• 1:56
  Speaker 1: host Creature Feature, a biology podcast, So I'm not actually
• 2:00
  Speaker 1: a physicist, but I have used a hula hoop before,
• 2:03
  Speaker 1: so I feel fairly confident I can talk about Saturn's
• 2:07
  Speaker 1: rings today. Oh. I think that makes you an engineer,
• 2:10
  Speaker 1: doesn't it. That's right, Just get me some tape and
• 2:14
  Speaker 1: a few paper clips, and boom, I'm an engineer. Well,
• 2:19
  Speaker 1: I actually don't wear a whole lot of rings. I
• 2:21
  Speaker 1: just have this one wedding ring, which my wife and
• 2:24
  Speaker 1: I picked up two days before our wedding on the
• 2:26
  Speaker 1: streets of Berkeley for about five bucks. And I think
• 2:29
  Speaker 1: at the time we were like, oh, this will work temporarily,
• 2:31
  Speaker 1: and here we are twenty years later, I'm still wearing
• 2:34
  Speaker 1: the same silver ring. No, that's so sweet. I love
• 2:37
  Speaker 1: that story. Yeah, it's a nice memory. It helps me
• 2:39
  Speaker 1: understand where I came from. And you know, in the
• 2:42
  Speaker 1: same way, we can look up at the night sky
• 2:44
  Speaker 1: and study the planets and use their rings to try
• 2:47
  Speaker 1: to get an idea of like where they came from,
• 2:49
  Speaker 1: what is the history of this planet? How did it
• 2:52
  Speaker 1: get that ring? Who gave it to it? And you know,
• 2:54
  Speaker 1: what is that wedding going to look like? So you're
• 2:56
  Speaker 1: saying because my ring was made in a lab, that
• 2:59
  Speaker 1: I two was made in a lab. Maybe your love
• 3:02
  Speaker 1: was grown in the lab, you know, which doesn't make
• 3:04
  Speaker 1: it any less authentic. I'm a big fan of labs
• 3:07
  Speaker 1: and research. It's very romantic test tube romance and welcome
• 3:14
  Speaker 1: to the podcast. Daniel and Jorge explain the universe in
• 3:17
  Speaker 1: which we try to grow your understanding of the nature
• 3:21
  Speaker 1: of this universe that we find ourselves and we cast
• 3:24
  Speaker 1: our minds out into the deepest darkness of space and
• 3:27
  Speaker 1: try to ring out understanding of everything that's out there
• 3:30
  Speaker 1: in the universe, and we zoom on into the tiniest
• 3:33
  Speaker 1: little things between our toes and under our fingernails, because
• 3:37
  Speaker 1: we want to understand the fundamental nature of the universe,
• 3:40
  Speaker 1: the nature of space and time itself, and matter and
• 3:43
  Speaker 1: energy and all those tiny little bits which, in their
• 3:47
  Speaker 1: two ing and frowing, come together to make the universe
• 3:49
  Speaker 1: that we know and love. My friend and co host
• 3:52
  Speaker 1: Jorge can't be with us today he is on vacation,
• 3:54
  Speaker 1: but we are very pleased to have the be Ringed,
• 3:57
  Speaker 1: be Jeweled, be Blinged Kiti two join this today. Well,
• 4:01
  Speaker 1: thank you for ringing me up for this episode. Yes,
• 4:05
  Speaker 1: I'm very excited. I love science, but that doesn't mean
• 4:09
  Speaker 1: I can't appreciate some good old fashioned cosmic jewelry. Well,
• 4:14
  Speaker 1: one thing I love about jewelry is that it really
• 4:16
  Speaker 1: does tell a story. You know, you talk to somebody
• 4:19
  Speaker 1: and you see them with ear rings or with a necklace,
• 4:22
  Speaker 1: you know that has a history. You know, maybe somebody
• 4:24
  Speaker 1: bought for them, or they got it for some big event,
• 4:27
  Speaker 1: or maybe they inherited it from their family, and it
• 4:29
  Speaker 1: tells like an even deeper story about where they came
• 4:32
  Speaker 1: from and their family history. So it's like everybody who's
• 4:35
  Speaker 1: wearing jewelry is walking around telling little stories about themselves. Yeah,
• 4:39
  Speaker 1: I love that. Or it bears an ancient curse? Are
• 4:44
  Speaker 1: we going to take a deep dark turn on this podcast?
• 4:48
  Speaker 1: I don't know. It is Saturn cursed? Is that where
• 4:51
  Speaker 1: we're going to discover maybe Aliens visited the Solar System
• 4:54
  Speaker 1: and had a war with the Octopi living under the
• 4:56
  Speaker 1: oceans of Insulatus, and the rings are just the left
• 4:59
  Speaker 1: over remnants that interstellar conflict. That's very spooky, and I
• 5:03
  Speaker 1: would love that story for a ring that I had,
• 5:06
  Speaker 1: that it was made by some kind of intergalactic war.
• 5:09
  Speaker 1: I think it is one of the things about the
• 5:12
  Speaker 1: Solar System that really adds a bit of magic to it,
• 5:16
  Speaker 1: adds a bit of artistry to it, because of course
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  Speaker 1: I think all the planets are lovely, but they're all orbs,
• 5:23
  Speaker 1: you know, they're they're all these roughly of course, not
• 5:26
  Speaker 1: exact precise spears, but you know, roughly spherical. But then
• 5:30
  Speaker 1: you have these rings. And it always when I see
• 5:34
  Speaker 1: Saturn that gives me a feeling of awe about the
• 5:38
  Speaker 1: mystery and artistry of space that I don't necessarily get
• 5:42
  Speaker 1: with other planets, absolutely because it's so easy to grab onto,
• 5:46
  Speaker 1: you know, it's so visible out there. And it must
• 5:49
  Speaker 1: have been an amazing moment in sixteen ten when Galileo
• 5:52
  Speaker 1: looked through his telescope and saw the rings of Saturn,
• 5:55
  Speaker 1: and how shocking to discover that planets can have these
• 5:59
  Speaker 1: incredible dis you know, these things are like ten times
• 6:01
  Speaker 1: the size of Saturn. We'll talk later about how Saturday
• 6:04
  Speaker 1: might have rings that go out like two hundred times
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  Speaker 1: the size of its radius. It's an incredible thing. Like
• 6:10
  Speaker 1: I have this little tiny ring on my finger. Imagine
• 6:12
  Speaker 1: if I was wearing a ring that was like two
• 6:14
  Speaker 1: hundred times the size of me. You know, some might
• 6:17
  Speaker 1: say that's a little overstated. It would be a statement piece,
• 6:20
  Speaker 1: for sure. You know. I was actually just in the
• 6:23
  Speaker 1: Galileo Museum in Florence, And when you think of Galileo
• 6:28
  Speaker 1: with his telescope, he's often depicted with this small, you know,
• 6:31
  Speaker 1: telescope he can hold in his hands. But you look
• 6:33
  Speaker 1: at the actual telescopes he used to observe Saturn and
• 6:37
  Speaker 1: they were huge. Yeah, he wasn't the inventor of the telescope,
• 6:40
  Speaker 1: but he was the first one to really perfect it
• 6:42
  Speaker 1: and then to turn it up on the skies, and
• 6:44
  Speaker 1: so he got like the biggest first scoop of all
• 6:47
  Speaker 1: these discoveries. You know, he saw the moons of Jupiter,
• 6:49
  Speaker 1: he saw the rings of Saturn. He's on mountains on
• 6:52
  Speaker 1: the Moon on a moment or like really look out
• 6:55
  Speaker 1: into the universe. And I think that one of the
• 6:57
  Speaker 1: most interesting things for me about it is that they
• 6:59
  Speaker 1: do reve yield the history of the Solar System. You know,
• 7:02
  Speaker 1: we look out unto the night sky and we want
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  Speaker 1: to understand not just what's out there, but why it's
• 7:07
  Speaker 1: out there and why it looks the way that it does.
• 7:10
  Speaker 1: And so anything that's weird or strange or unusual that's
• 7:13
  Speaker 1: not just like a ball floating in the sky, Let's
• 7:16
  Speaker 1: just ask the question, how did that get there? How
• 7:19
  Speaker 1: long can that live? What does that tell us about
• 7:21
  Speaker 1: the history of the Solar System? Have those rings just
• 7:24
  Speaker 1: been there for the last million years? Have they been
• 7:26
  Speaker 1: there since the beginning of the Solar System? Why do
• 7:28
  Speaker 1: Saturn have rings and not other planets? Or do they right?
• 7:31
  Speaker 1: There's just so many immediate questions that you can ask
• 7:34
  Speaker 1: when you see these rings, and then those questions open
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  Speaker 1: the door to try to understand the formation of the
• 7:39
  Speaker 1: Solar System. The other aspect, which is super fascinating for me,
• 7:42
  Speaker 1: is just thinking about what physics can do. You know,
• 7:46
  Speaker 1: you throw a whole bunch of stuff out into space
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  Speaker 1: and it forms stars and it forms planets, But not
• 7:51
  Speaker 1: just that right, it can also do these other incredible things.
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  Speaker 1: And it's all these fascinating little wrinkles, these little bits
• 7:57
  Speaker 1: of bling that really show us what gravity is capable
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  Speaker 1: of and the interplay between gravity and all the other forces. So,
• 8:04
  Speaker 1: as we'll see on today's episode, these rings will teach
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  Speaker 1: us a lot about the nature of the Solar System
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  Speaker 1: and the universe that we live in. And so on
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  Speaker 1: today's episode we'll be tackling exactly that question. How do
• 8:21
  Speaker 1: planets get rings? Okay, I'm gonna stop you right there,
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  Speaker 1: because I think I have the answer. It is aliens,
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  Speaker 1: giant aliens doing ring toss with our planets, or maybe
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  Speaker 1: it's hula hoops from a leftover enormous alien birthday party.
• 8:37
  Speaker 1: We're basically their garbage bin. But it's an interesting question
• 8:40
  Speaker 1: not just why are there rings, but how do planets
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  Speaker 1: get rings? Where do they come from? Why do some
• 8:45
  Speaker 1: planets have rings and others don't. Why do some planets
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  Speaker 1: have more moons and fewer rings. What is the connection
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  Speaker 1: between rings and moons? Can moons have rings? Can rings
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  Speaker 1: exist on planets in other Solar systems? Is our Solar
• 8:58
  Speaker 1: System weird for having this incredible planet with these huge rings,
• 9:03
  Speaker 1: or are we weird for not having rings around every
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  Speaker 1: single planet? These are the kinds of questions we can
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  Speaker 1: now ask about our solar system because we have looked
• 9:11
  Speaker 1: out through our telescopes into even other solar systems around
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  Speaker 1: other stars to try to get an answer to the
• 9:17
  Speaker 1: question of is our solar system strange or is our
• 9:21
  Speaker 1: solar system totally vanilla and typical. I find that an
• 9:25
  Speaker 1: interesting way to describe if our solar system is similar
• 9:29
  Speaker 1: to other solar systems, which is boring and vanilla. Well,
• 9:33
  Speaker 1: it's a deep question, right, like are we typical? Are
• 9:35
  Speaker 1: we boring? If alien scientists are studying the whole galaxy,
• 9:38
  Speaker 1: would they find us an interesting case study or would
• 9:41
  Speaker 1: they be like, oh, yeah, another one, just like all
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  Speaker 1: the other sixty five million systems that I've already studied. Right,
• 9:47
  Speaker 1: we'd like to think that we are special in some sense.
• 9:50
  Speaker 1: We'd like to imagine that we are at the center
• 9:52
  Speaker 1: of the universe. We are unusual, we are sparkling, we
• 9:54
  Speaker 1: are exceptional. On the other hand, I'd like to believe
• 9:56
  Speaker 1: that we are vanilla, that we are boring, because that
• 9:59
  Speaker 1: means it's probably more of us, right, That means it's
• 10:01
  Speaker 1: probably life everywhere. One of my favorite things about this
• 10:04
  Speaker 1: kind of question, is our solar system typical or not?
• 10:07
  Speaker 1: Is that the answer is fascinating either way. Either we're
• 10:09
  Speaker 1: incredibly unusual and then we get to ask why, or
• 10:12
  Speaker 1: we're not, in which case we got lots of neighbors. Yeah,
• 10:15
  Speaker 1: so you would favor us being basic solar system with
• 10:19
  Speaker 1: our ugg boots and our Saturn's rings. That is kind
• 10:22
  Speaker 1: of an interesting personality quick personality tests, like would you
• 10:25
  Speaker 1: prefer our solar system to be unique and special in
• 10:30
  Speaker 1: us to be the only planet with life or would
• 10:33
  Speaker 1: you prefer us to be run of the mill lots
• 10:37
  Speaker 1: of solar systems like ours out there and not feel
• 10:39
  Speaker 1: so alone. I agree with you. I hope we're basic
• 10:43
  Speaker 1: so that we've got some friends out there. Exactly, We
• 10:46
  Speaker 1: can't answer that question directly today because our telescopes are
• 10:49
  Speaker 1: not powerful enough to look through the atmospheres of exo planets.
• 10:53
  Speaker 1: But we can look in our own backyard and try
• 10:55
  Speaker 1: to understand how our solar system formed and if there's
• 10:58
  Speaker 1: anything in it that we cannot explained. And it's an
• 11:01
  Speaker 1: incredible piece of science to look around you and understand
• 11:04
  Speaker 1: how we came together to build a model for the
• 11:07
  Speaker 1: processes that could have formed such incredible structures, and to
• 11:11
  Speaker 1: think about how long they might have taken. You know,
• 11:13
  Speaker 1: we've done something similar here on Earth by looking under
• 11:15
  Speaker 1: our feet and asking questions like do we understand how
• 11:18
  Speaker 1: the Earth formed? And how the mountains have formed? And
• 11:21
  Speaker 1: all the ridges that we see in the layers of rock,
• 11:24
  Speaker 1: and those things are clues, the clues that led us
• 11:26
  Speaker 1: to understand something really shocking, that the Earth is billions
• 11:30
  Speaker 1: of years old, not thousands of years old. Right. We
• 11:33
  Speaker 1: have the evidence all around us to reveal the story
• 11:37
  Speaker 1: of the formation of the Solar System, but not just
• 11:40
  Speaker 1: here on Earth, out there in space, and one of
• 11:42
  Speaker 1: the funnest bits is to look at the rings around
• 11:45
  Speaker 1: those planets. So that's what we're focusing on today. And
• 11:48
  Speaker 1: I was curious whether people understood rings, whether rings were
• 11:51
  Speaker 1: still a big source of mystery, or people thought they
• 11:54
  Speaker 1: pretty much understood where they came from. So I went
• 11:57
  Speaker 1: out there to our cadre of Internet volunteers, who are
• 12:00
  Speaker 1: my random questions without a chance to prepare, which gives
• 12:03
  Speaker 1: us a sense for what people know, what they think about,
• 12:05
  Speaker 1: and what they want to hear about. If you'd like
• 12:07
  Speaker 1: to participate for future episodes. Please don't be shy, just
• 12:10
  Speaker 1: write to me two questions at Daniel and Jorge dot com.
• 12:14
  Speaker 1: Before you hear these answers, think to yourself, do you
• 12:16
  Speaker 1: have a good idea of where rings come from on planets?
• 12:20
  Speaker 1: Here's what our listeners had to say, UM, and I'm
• 12:23
  Speaker 1: pretty sure that I learned about this that UM like
• 12:26
  Speaker 1: it's asteroids colliding near the planet itself and the remnants
• 12:33
  Speaker 1: of those asteroids going into orbit and creating a sort
• 12:37
  Speaker 1: of disc. I think the two classical ways are by
• 12:41
  Speaker 1: planets capturing space debris um that's just floating through the
• 12:44
  Speaker 1: Solar System, or by recapturing debris caused by an impact.
• 12:48
  Speaker 1: But I've also heard of a moon orbiting Saturn. I
• 12:52
  Speaker 1: believe that has a geyser and when the guys are
• 12:55
  Speaker 1: spits out water um it forms into ice crystals, and
• 12:59
  Speaker 1: then that joins the rings of Saturn. So maybe that's
• 13:02
  Speaker 1: another option. Well, the rings are kind of like small satellites,
• 13:09
  Speaker 1: I would say, like small moons, Like we have the
• 13:12
  Speaker 1: most most really tiny moons that get around the planet.
• 13:16
  Speaker 1: Each planet has its own way of doing the rings. Well,
• 13:22
  Speaker 1: I wanted to say that planets can get rings if
• 13:24
  Speaker 1: they collide with big rocky bodies, but I don't know
• 13:27
  Speaker 1: how that would work with like gas giants and how
• 13:31
  Speaker 1: they got their rings. So I'm going to guess that
• 13:33
  Speaker 1: it's just stuff that is left over um from when
• 13:37
  Speaker 1: the planet was formed, and it was just stuff that
• 13:39
  Speaker 1: was so far away when it was being formed that
• 13:41
  Speaker 1: it didn't become part of the planet, but it was
• 13:43
  Speaker 1: still close enough to be influenced by the gravity of it.
• 13:45
  Speaker 1: I'm almost certain it's got to do with the acreation
• 13:51
  Speaker 1: process of when a planets formed and the attraction of
• 13:57
  Speaker 1: the stuff towards the planet. Apart from that, I'm not
• 14:02
  Speaker 1: really sure actually, because I think planets form when like
• 14:07
  Speaker 1: a heavy metal gets caught in orbit around the star,
• 14:11
  Speaker 1: so I think something similar happens around the planet. Debris
• 14:14
  Speaker 1: and maybe rocks or particles of ice or something um
• 14:19
  Speaker 1: gather around a planet in much the same way that
• 14:22
  Speaker 1: planets gather around stars. Does all seem like really intelligent answers,
• 14:28
  Speaker 1: but I still kind of like my giant alien ring
• 14:31
  Speaker 1: toss theory. We'll put it on the list as the
• 14:35
  Speaker 1: dark horse theory that might storm out at the end
• 14:37
  Speaker 1: if we can't explain it with any of the other theories.
• 14:40
  Speaker 1: So it seems like there are so many options for
• 14:43
  Speaker 1: what these rings could be made of. How on Earth
• 14:46
  Speaker 1: are we, or I should say, how in our Solar
• 14:48
  Speaker 1: system are we going to be able to figure out
• 14:50
  Speaker 1: what exactly they're made of? If there are so many
• 14:53
  Speaker 1: different theories, so many different options for what they could
• 14:56
  Speaker 1: be made of. Yeah, it's a great question. I listen
• 14:58
  Speaker 1: to these answers and seems to me like they form
• 15:01
  Speaker 1: in roughly two categories. There are some folks that say
• 15:05
  Speaker 1: that it's basically debris from other stuff that broke up,
• 15:08
  Speaker 1: like maybe you had comments or moons that smashed new
• 15:11
  Speaker 1: each other and basically just made a big mess, you know.
• 15:14
  Speaker 1: But then you have to wonder, like why don't those
• 15:16
  Speaker 1: things gather together to make a new moon or to
• 15:19
  Speaker 1: make a new comment or something. And the other category
• 15:22
  Speaker 1: is like, maybe it's just left over from when the
• 15:24
  Speaker 1: planet was formed, the same stuff that formed the planet,
• 15:27
  Speaker 1: but some of it didn't get into the planet. So
• 15:29
  Speaker 1: it seems like those are two different categories of ideas,
• 15:32
  Speaker 1: And you ask a great question, how could we possibly
• 15:34
  Speaker 1: ever figure this out? How could we know what the
• 15:37
  Speaker 1: history is of the Solar System? And the answer is that.
• 15:40
  Speaker 1: Of course, we can't just like watch a video of
• 15:42
  Speaker 1: its formation, though we'd love to, but we can just
• 15:45
  Speaker 1: look around us for clues. We can try to build
• 15:47
  Speaker 1: up models for how rings might form, and then compare
• 15:50
  Speaker 1: the details of those models to what we see. So
• 15:53
  Speaker 1: the short answer is we need more money and more
• 15:55
  Speaker 1: data to measure these rings, to look closely at them,
• 15:59
  Speaker 1: to see what they are made out of, how much
• 16:01
  Speaker 1: mass they have, what their distribution is. The more detail
• 16:04
  Speaker 1: we can get about what they look like and what
• 16:06
  Speaker 1: they're made out of, the better we can compare them
• 16:08
  Speaker 1: to predictions from our theories about how they were formed.
• 16:12
  Speaker 1: I mean, it sounds like a worthy use of funding. However,
• 16:16
  Speaker 1: might I suggest an n f T of a farting
• 16:19
  Speaker 1: panda instead? I'll put that on the proposed list and
• 16:22
  Speaker 1: see where it goes. So when we're talking about rings,
• 16:26
  Speaker 1: like what is it? Because you know my wedding ring
• 16:29
  Speaker 1: is this solid band that sits around my finger. Hula
• 16:34
  Speaker 1: hoop is this very thin tourists that you kind of
• 16:39
  Speaker 1: use the motion of your hips to keep moving around
• 16:43
  Speaker 1: with its momentum? So what are the rings that are
• 16:46
  Speaker 1: around Saturn? Are they spinning around like a hula hoop
• 16:50
  Speaker 1: or they just kind of sitting on it, like my
• 16:52
  Speaker 1: wedding ring. It's a great question, and when it comes
• 16:55
  Speaker 1: to astronomy, you always have to start with the definition,
• 16:58
  Speaker 1: which immediately puts you in to a swamp, because nothing
• 17:02
  Speaker 1: falls nicely into clean categories out there in space. You know,
• 17:05
  Speaker 1: what's a planet, what's a minor planet, what's a centaur.
• 17:08
  Speaker 1: A lot of these definitions come from history because we
• 17:11
  Speaker 1: didn't really understand what was going on, and we just
• 17:14
  Speaker 1: sort of named things randomly, and then we were sort
• 17:16
  Speaker 1: of stuck with different categories and so often they could
• 17:19
  Speaker 1: be a bit of a mess. Well, we're lucky in
• 17:21
  Speaker 1: biology because species is super simple and never has that
• 17:25
  Speaker 1: problem exactly. Nature doesn't confine itself to our categories. Was
• 17:29
  Speaker 1: out there in the universe is not things that fall
• 17:31
  Speaker 1: into crisply defined different boxes. It's a whole spectrum of stuff, right,
• 17:36
  Speaker 1: And so we just got to put these arbitrary definitions
• 17:38
  Speaker 1: out there so that we can talk to each other
• 17:40
  Speaker 1: about it. So one of the most common definitions of
• 17:42
  Speaker 1: a ring is a disc or ring composed of solid
• 17:46
  Speaker 1: materials such as dust or moonlits. Moonlits. That sounds really cute,
• 17:51
  Speaker 1: what's a moonlit moon is like a little moon, you know,
• 17:54
  Speaker 1: like a little Moonito, the old baby moon, exactly a
• 17:59
  Speaker 1: little my in your moon. Immediately understand, these rings are
• 18:02
  Speaker 1: not actually a solid object. It's not like a hulu, right,
• 18:05
  Speaker 1: or the rings around Saturn are not huge circles. They're
• 18:08
  Speaker 1: actually a bunch of tiny little particles, a bunch of
• 18:12
  Speaker 1: chunks that are moving in the same orbit. And so
• 18:14
  Speaker 1: from far away it looks like a ring. Of course,
• 18:17
  Speaker 1: it looks like a single hula hoop, for example, or
• 18:19
  Speaker 1: a wedding ring. But if you zoomed in closely, you
• 18:22
  Speaker 1: see it's actually a bunch of individual pieces that are
• 18:24
  Speaker 1: not touching each other. So cartoons have lied to me.
• 18:27
  Speaker 1: I cannot drive a race car or a skateboard around
• 18:32
  Speaker 1: the rings of Saturn. That's right. You can't do Mario
• 18:34
  Speaker 1: Kart on the rings of Saturn and you would fall
• 18:37
  Speaker 1: right through. It's very disappointing. Cartoons play it real fast
• 18:40
  Speaker 1: and loose with physics I'm discovering. And so basically a
• 18:45
  Speaker 1: ring is just like a disc of material in a
• 18:47
  Speaker 1: single orbit, moving all around. And that makes it a
• 18:49
  Speaker 1: little bit unusual because orbits are usually for one object
• 18:53
  Speaker 1: you know, like the Moon orbits the Earth and there's
• 18:55
  Speaker 1: nothing else in the Moon's orbit. It's not like there's
• 18:57
  Speaker 1: something else on the other side, or the Earth disorbiting
• 19:00
  Speaker 1: the Sun and there's nothing else in Earth's orbit, right,
• 19:03
  Speaker 1: it clears its own path. So it's a bunch of
• 19:07
  Speaker 1: individual things sharing a single orbit, kind of like a
• 19:11
  Speaker 1: lazy river at a water park exactly so to like
• 19:15
  Speaker 1: a lazy river. And once you define it that way,
• 19:18
  Speaker 1: you can ask questions like, well, what counts as a ring?
• 19:21
  Speaker 1: You know, does it have to be natural? For example,
• 19:23
  Speaker 1: like Earth has a bunch of stuff out there in space,
• 19:26
  Speaker 1: things we have launched out there, a bunch of satellites
• 19:29
  Speaker 1: in the same orbit, you know, zooming all around. Does
• 19:32
  Speaker 1: that count as a ring? Have we built our own
• 19:35
  Speaker 1: ring system around the Earth because all of the junk
• 19:38
  Speaker 1: that we put out there in space. Nobody talks about
• 19:40
  Speaker 1: Earth's rings, but technically, you know, it seems like that
• 19:43
  Speaker 1: might qualify. There's no like minimum mass requirement for the
• 19:47
  Speaker 1: rings as far as I can tell, so we're one
• 19:49
  Speaker 1: step closer to Halo am I right, high fibes everyone
• 19:53
  Speaker 1: who plays computer games. Another requirement for rings usually is
• 19:57
  Speaker 1: that they are pretty flat right, if you have just
• 20:00
  Speaker 1: like a swarm of spherical swarm of objects, then your
• 20:03
  Speaker 1: planet is just surrounded by junk. A ring is typically
• 20:05
  Speaker 1: something which is flattened, right, it's more like a disc.
• 20:08
  Speaker 1: And this already shows off what's going on with gravity.
• 20:11
  Speaker 1: You know, gravity has pulled the planet together and it's spinning,
• 20:14
  Speaker 1: and it's also pulled the ring together. And the reason
• 20:17
  Speaker 1: that rings form in disks is the same reason that
• 20:20
  Speaker 1: the Solar system is a disc. Right. That most of
• 20:22
  Speaker 1: the stuff is spinning in the same direction, along the
• 20:25
  Speaker 1: same plane, and that's because of conservation of angular momentum.
• 20:29
  Speaker 1: Stuff that spinning keeps spinning, and if gravity pulls it together,
• 20:33
  Speaker 1: it keeps spinning. It's harder for gravity to pull together
• 20:36
  Speaker 1: towards the spin axis than along the spin axis the
• 20:40
  Speaker 1: same way. For example, that like Earth resists falling into
• 20:44
  Speaker 1: the Sun because of its speed because of its angular momentum, right,
• 20:47
  Speaker 1: But the Earth didn't resist falling into the Sun's plane.
• 20:50
  Speaker 1: So gravity is free to compress things down into a
• 20:53
  Speaker 1: flat disc. But angular momentum keeps things spinning and keep
• 20:56
  Speaker 1: things from falling in That's what gives rings these sort
• 20:59
  Speaker 1: of flat structure. So that's another typical thing we expect
• 21:02
  Speaker 1: of rings that they're not spherical distributions of stuff. They're
• 21:06
  Speaker 1: like these flat disks. Because that's sort of like if
• 21:08
  Speaker 1: you pile a bunch of peas on a plate and
• 21:11
  Speaker 1: then spin the plate, all the p's are going to
• 21:14
  Speaker 1: scatter outwards and get everywhere, but in sort of a
• 21:17
  Speaker 1: flat circle. I've never done that experiment, but yes, in
• 21:20
  Speaker 1: my mind that that's exactly what you don't do that.
• 21:24
  Speaker 1: We call it pea spinning in this household. But in
• 21:27
  Speaker 1: our Solar system, of course, there's gravity, and gravity would
• 21:30
  Speaker 1: hold those p's in right, so those p's would end
• 21:33
  Speaker 1: up in like a circular orbit exactly instead of like
• 21:35
  Speaker 1: a bunch of different orbits. And so that's why the
• 21:38
  Speaker 1: planets are all roughly in the same plane, because they
• 21:41
  Speaker 1: have the same spin from the original blob of gas
• 21:44
  Speaker 1: and dust that formed our Solar system. And so that's
• 21:47
  Speaker 1: already a clue that tells you something about the origins
• 21:50
  Speaker 1: of these rings, because if we're if rings were formed
• 21:53
  Speaker 1: with the planet, then you would expect them to have
• 21:56
  Speaker 1: roughly the same alignment, the same spin as the planet.
• 21:58
  Speaker 1: And if they were not, then they necessarily have to
• 22:01
  Speaker 1: have that same spin that came in from like a
• 22:03
  Speaker 1: comet that smashed into the planet or broke up a moon,
• 22:06
  Speaker 1: it might give you a different kind of distribution. So
• 22:08
  Speaker 1: already that's a clue that tells you something about where
• 22:11
  Speaker 1: rings might have come from. Oh, that's really interesting. So
• 22:14
  Speaker 1: when you have debris from a planet's formation, everything's spinning
• 22:20
  Speaker 1: at the same rate, sort of going with the same flow.
• 22:23
  Speaker 1: But then if you have something smash into a planet,
• 22:26
  Speaker 1: release all these all this debris and it starts orbiting
• 22:30
  Speaker 1: the planet, it doesn't need to spin at the same
• 22:34
  Speaker 1: rate as the planet spins. Just like our moon. Our
• 22:38
  Speaker 1: moon doesn't spin at the same rate as Earth. Right,
• 22:41
  Speaker 1: that's right now, it does not, right, So that would
• 22:43
  Speaker 1: suggest that the moon was not necessarily formed when the
• 22:47
  Speaker 1: Earth was formed, right exactly. And we think that the
• 22:49
  Speaker 1: moon is the result of a huge collision, that something
• 22:53
  Speaker 1: came and smashed into the Earth and released an enormous
• 22:55
  Speaker 1: amount of debris which then coalesced into a moon. Right,
• 23:00
  Speaker 1: So that after that collision, Earth may have had a
• 23:03
  Speaker 1: very large cloud of debris which then probably coalesced into
• 23:07
  Speaker 1: a ring system, which then further gathered into a moon.
• 23:11
  Speaker 1: So our moon may have once been a ring. So
• 23:14
  Speaker 1: do we know with the rings of Saturn if they
• 23:17
  Speaker 1: are moving at the same rate of Saturn where to
• 23:20
  Speaker 1: differ rate The rings of Saturn are especially complicated because
• 23:23
  Speaker 1: there are so many rings, and some of them are
• 23:25
  Speaker 1: moving with Saturn, and some of them may actually be
• 23:27
  Speaker 1: rotating the other direction. It's really tricky and complicated, and
• 23:32
  Speaker 1: we'll dig into it in a moment when we talk
• 23:34
  Speaker 1: about how the rings of planets are formed, the various
• 23:38
  Speaker 1: theories and the pieces of evidence for and against the
• 23:41
  Speaker 1: first Let's take a quick break. All right, I'm gonna
• 23:45
  Speaker 1: try to imagine those rings moving in different directions without
• 23:49
  Speaker 1: getting sea sick during the break. All right, we are back.
• 24:05
  Speaker 1: I got a little dizzy trying to think about Saturn's rings,
• 24:09
  Speaker 1: some moving in one direction, others moving in another. It's
• 24:12
  Speaker 1: pretty trippy. But yeah, I still have a lot of
• 24:15
  Speaker 1: questions about these rings we're talking about, like how maybe
• 24:20
  Speaker 1: they're formed, whether they're formed when the planet forms out
• 24:24
  Speaker 1: of basically the same stuff that the planet is formed
• 24:28
  Speaker 1: out of, or if it is made out of kind
• 24:31
  Speaker 1: of some outside stuff, stuff that wasn't around when the
• 24:33
  Speaker 1: planet was formed, like by a collision, Like how maybe
• 24:36
  Speaker 1: our moon was formed do we know like what stuff
• 24:41
  Speaker 1: is inside of these rings? And how do we know
• 24:44
  Speaker 1: what is inside a ring without actually going up there
• 24:47
  Speaker 1: and taking a scoop of it. Yeah, that's a good question.
• 24:50
  Speaker 1: One thing we can do is we can look at
• 24:51
  Speaker 1: it through a telescope and see what kind of light
• 24:53
  Speaker 1: it reflects. Is it opaque, is it transparent? Is transparent
• 24:56
  Speaker 1: to different kinds of light? Each planet reflects sunlight, but
• 24:59
  Speaker 1: or all so emits particles, And so we can see
• 25:02
  Speaker 1: whether the rings create shadows in some sort of the
• 25:05
  Speaker 1: wind of Jupiter or the wind of Saturn. And we
• 25:08
  Speaker 1: have also sent probes out there, and these probes will
• 25:11
  Speaker 1: talk about them in a minute have made some really
• 25:13
  Speaker 1: startling discoveries by getting very close up to these rings.
• 25:17
  Speaker 1: But first I want to talk about sort of the
• 25:18
  Speaker 1: general question like talked a minute ago about the Earth's
• 25:21
  Speaker 1: moon and how it used to be a ring. And
• 25:23
  Speaker 1: you know, in my mind, one of the first question
• 25:24
  Speaker 1: is is like why do sometimes things form together into
• 25:28
  Speaker 1: a moon and sometimes they don't and they stay as
• 25:30
  Speaker 1: rings or is there like a process there where every
• 25:33
  Speaker 1: ring eventually turns into a moon. It's really fascinating question,
• 25:37
  Speaker 1: and it turns out to be totally dominated by the
• 25:39
  Speaker 1: gravity of the planet and how far you are away
• 25:42
  Speaker 1: from that planet. So Saturn's rings could conceivably have turned
• 25:48
  Speaker 1: into moons if they had been in a different situation. Conceivably. Yeah,
• 25:52
  Speaker 1: And it actually turns out the Saturn's rings have little
• 25:55
  Speaker 1: moonlits inside them that move around and shepherd them and
• 25:58
  Speaker 1: keep them apart. Though really fun. But the crucial thing
• 26:01
  Speaker 1: that determines whether something is a moon or a ring,
• 26:03
  Speaker 1: whether it gets torn up into little bits, or whether
• 26:06
  Speaker 1: it gets clumped together by gravity, is the gravity of
• 26:09
  Speaker 1: the host planet. You know, you have a bunch of
• 26:11
  Speaker 1: stuff out in the middle of space, gravity will eventually
• 26:13
  Speaker 1: gather it together. Gravity is very, very weak, it's the
• 26:16
  Speaker 1: weakest force we know. But it's also very patient and
• 26:19
  Speaker 1: eventually will pull things together to make a clump. So
• 26:22
  Speaker 1: you might expect that all rings would be transient, that
• 26:25
  Speaker 1: they would be eventually just gathered together into a moon,
• 26:28
  Speaker 1: but that's not necessarily the case because of the gravity
• 26:31
  Speaker 1: of the planet. This gravity does more than just pull
• 26:34
  Speaker 1: the moon into orbit or keep the rings in orbit.
• 26:37
  Speaker 1: You can also pull them apart. This is the concept
• 26:39
  Speaker 1: we've talked about on the podcast before, called tidal forces.
• 26:43
  Speaker 1: The ideas they have a very strong source of gravity
• 26:45
  Speaker 1: like Jupiter or a black hole, or the Sun or
• 26:48
  Speaker 1: even the Earth, and it's pulling on you right But
• 26:51
  Speaker 1: the strength of its force on you depends on how
• 26:54
  Speaker 1: close you are to that object. So if your feet
• 26:57
  Speaker 1: are closer to the Sun than your head, then the
• 27:00
  Speaker 1: Sun is pulling on your feet harder than it's pulling
• 27:03
  Speaker 1: on your head, and effectively it means it's trying to
• 27:05
  Speaker 1: pull your head off of your body. Nobody ever said
• 27:11
  Speaker 1: the Sun was a nice guy. Okay, oh, I know what.
• 27:14
  Speaker 1: I know that right now in July, and that's happening
• 27:17
  Speaker 1: right now. If you stand on the surface of the Earth,
• 27:19
  Speaker 1: then the Earth is literally trying to pull your head
• 27:22
  Speaker 1: off of your body. Now we've evolved with strong enough
• 27:25
  Speaker 1: next or is this this and the title forces here
• 27:27
  Speaker 1: are not that strong? Yeah, take that Earth. But if
• 27:30
  Speaker 1: you're in a situation where the gravitational forces get strong
• 27:34
  Speaker 1: very quickly, so the force on your feet is much
• 27:37
  Speaker 1: stronger than the force on your head, you can be
• 27:39
  Speaker 1: torn apart. And if you're near a black hole for example,
• 27:42
  Speaker 1: where this is very dramatic, this is what we call spaghettification,
• 27:45
  Speaker 1: you can get pulled apart into tiny little pieces, the
• 27:47
  Speaker 1: most delicious way to describe a horrific that exactly. And
• 27:52
  Speaker 1: we've seen this happen when comet shoemaker Levy came into
• 27:55
  Speaker 1: the Solar System in the nineties. It was headed for
• 27:57
  Speaker 1: an impact with Jupiter, but before it hit Jupiter, it
• 28:00
  Speaker 1: made a near miss and Jupiter pulled it apart into
• 28:03
  Speaker 1: twenty six pieces. So you have this comment coming into
• 28:07
  Speaker 1: the Solar System, which got shredded by jupiter gravity. Then
• 28:10
  Speaker 1: it went around the Sun and it hit Jupiter twenty
• 28:13
  Speaker 1: six different times, which is pretty awesome for everybody to
• 28:16
  Speaker 1: look at these huge fireballs the size of the Earth.
• 28:19
  Speaker 1: But for our six today, this is just a demonstration
• 28:22
  Speaker 1: of tidal forces. So a planet doesn't just pull stuff
• 28:25
  Speaker 1: in and keep it in orbit. It can also tear
• 28:27
  Speaker 1: it apart if you are close enough, I see so
• 28:30
  Speaker 1: because gravity gets weaker the further away you are from something,
• 28:35
  Speaker 1: but stronger the closer you are to something. If part
• 28:39
  Speaker 1: of you is far enough away that it's pretty weak
• 28:41
  Speaker 1: and it's not pulling on you, but the other part
• 28:43
  Speaker 1: of you is closer and it's tugging on you more strongly,
• 28:47
  Speaker 1: that part of you is going to get kind of
• 28:49
  Speaker 1: ripped off of the other part of you. Is that
• 28:51
  Speaker 1: what's happening to these poor baby little moonlits, That's what's
• 28:56
  Speaker 1: happening to those rings. So if you're a big blob
• 28:58
  Speaker 1: of material and you're too close to a planet, you
• 29:01
  Speaker 1: cannot form a moon because the planet will just keep
• 29:04
  Speaker 1: tearing you apart. If you're far enough away, then you
• 29:07
  Speaker 1: can form a moon. So there's a limit there. It's
• 29:09
  Speaker 1: called the Roche limit r O. C h E, after
• 29:12
  Speaker 1: a scientist who came up with this idea. If you
• 29:15
  Speaker 1: are closer than the Roche limit, then you cannot form
• 29:18
  Speaker 1: a gravitationally bound object because the gravity of the planet
• 29:21
  Speaker 1: is stronger than you're inherent gravity to hold yourself together.
• 29:24
  Speaker 1: If you're out past it, then the tidal forces are
• 29:26
  Speaker 1: so weak that you can clump the ring together into
• 29:29
  Speaker 1: a moon. So past the Roche limit you get moons.
• 29:32
  Speaker 1: Closer in than the Roche limit, you get rings. So
• 29:36
  Speaker 1: Saturn's rings are too close to Saturn itself to form
• 29:41
  Speaker 1: the moon, whereas our moon, which maybe started as a ring,
• 29:46
  Speaker 1: was far enough away that it could do its own
• 29:49
  Speaker 1: thing without Earth overbearing and deciding its fate for it.
• 29:53
  Speaker 1: That's exactly right, and it depends a little bit on
• 29:56
  Speaker 1: like what you're made out of. The roche limit itself
• 29:58
  Speaker 1: is technically just as me your hell together gravitationally, but
• 30:01
  Speaker 1: things can also be held together in different ways. You know,
• 30:04
  Speaker 1: if you have a blob of diamond, for example, as
• 30:06
  Speaker 1: opposed to a loose bag of golf balls, then the
• 30:09
  Speaker 1: diamond is going to be able to hold itself together
• 30:11
  Speaker 1: closer to a planet than your bag of golf balls.
• 30:14
  Speaker 1: I wish my wedding ring was a bag of golf balls. Now,
• 30:17
  Speaker 1: that would be fun. I hope your husband listens to
• 30:19
  Speaker 1: this podcast to hear you complaining about his gift to you.
• 30:24
  Speaker 1: There's a beautiful gift of love. I wish it was
• 30:26
  Speaker 1: a bag of golf balls. Well, in the case of
• 30:30
  Speaker 1: our system, for example, you know, the moon holds itself together,
• 30:33
  Speaker 1: but if it was closer to the Earth, the Earth
• 30:35
  Speaker 1: would shred it. Our moon is about three five thousand
• 30:39
  Speaker 1: kilometers away, and the roche limit for the Earth and
• 30:42
  Speaker 1: an object the size of the moon is about ten
• 30:45
  Speaker 1: thousand kilometers, so the Moon would have to be much
• 30:48
  Speaker 1: much closer to the Earth in order for the Earth
• 30:51
  Speaker 1: to pull it apart um and make it into a
• 30:53
  Speaker 1: ring system. And so that's why the moon is a moon.
• 30:56
  Speaker 1: In a similar way. You know, the Sun has a
• 30:58
  Speaker 1: tidal force on the Earth, pulling on the part of
• 31:01
  Speaker 1: the Earth that's closer to its stronger than it's pulling
• 31:03
  Speaker 1: on part of the Earth that's further from it. So
• 31:05
  Speaker 1: the Sun is trying to rip the Earth apart, but
• 31:08
  Speaker 1: the Earth is too far away, it's too strong. It
• 31:10
  Speaker 1: has structural integrity that keeps the Sun from destroying us
• 31:14
  Speaker 1: or about a hundred and fifty million kilometers from the Sun.
• 31:17
  Speaker 1: If we were just less than a million kilometers, then
• 31:20
  Speaker 1: the Earth would get pulled apart and we get torn
• 31:22
  Speaker 1: into a ring system around the Sun. Seems like planetary
• 31:25
  Speaker 1: bodies are like complicated friendships. You've got to set strong
• 31:29
  Speaker 1: boundaries or else you're going to get destroyed exactly. So
• 31:33
  Speaker 1: you just you gotta know where you are. You know,
• 31:34
  Speaker 1: you've got to have the conversation sometimes to figure this out. Listen, son,
• 31:38
  Speaker 1: we love you. You provide us with energy that gives
• 31:41
  Speaker 1: us food. But you know, if we're too close to you,
• 31:44
  Speaker 1: we all die. So you know how it is. And
• 31:46
  Speaker 1: so this is the basic physics of it, right, You
• 31:48
  Speaker 1: get too close, you turn into a ring. You stay
• 31:50
  Speaker 1: far away, you can be a moon. But that doesn't
• 31:52
  Speaker 1: answer the question of like where these things come from,
• 31:55
  Speaker 1: because there's still two basic ideas there. One is that
• 31:59
  Speaker 1: some of this stuff is from the original formation of
• 32:02
  Speaker 1: the Solar System. You know, you have this huge cloud
• 32:05
  Speaker 1: of gas and dust. A lot of it formed the Sun.
• 32:07
  Speaker 1: Some of the clumps together to form planets. You can
• 32:10
  Speaker 1: imagine that some of the stuff is close enough to
• 32:12
  Speaker 1: the planet that it gets trapped by the planet's gravity,
• 32:15
  Speaker 1: but not so close that it actually gets sucked in.
• 32:17
  Speaker 1: It has like too much angular momentum to actually fall
• 32:20
  Speaker 1: to the Earth, you know, the same way, like the
• 32:23
  Speaker 1: Earth right now has particles that are trapped by its
• 32:26
  Speaker 1: gravity and also particles that are not. The Earth's atmosphere
• 32:29
  Speaker 1: is boiling away into space. So you can imagine that
• 32:33
  Speaker 1: at the edge of the planetary formation, there might have
• 32:35
  Speaker 1: been particles there that didn't quite get captured by the gravity,
• 32:39
  Speaker 1: but they're too close to clump together into their own moon.
• 32:42
  Speaker 1: So that's one theory of how these rings get formed.
• 32:45
  Speaker 1: They're like the fastest moving bits of the planet didn't
• 32:48
  Speaker 1: quite get captured, but they're not fast enough moving to
• 32:51
  Speaker 1: be like out on a further orbit, far enough away
• 32:53
  Speaker 1: where they could make their own moon. So the other
• 32:56
  Speaker 1: theory has to do with something that wasn't there during
• 33:00
  Speaker 1: in the origin of the Solar System coming in and
• 33:04
  Speaker 1: creating some debris around Saturn or whatever planet decides to
• 33:08
  Speaker 1: make a ring. Yeah, so the first theory that they
• 33:11
  Speaker 1: are made with the planet that suggests the rings are old, right,
• 33:14
  Speaker 1: that they're as old as the Solar System, like four
• 33:17
  Speaker 1: and a half billion years old. The other theories you
• 33:19
  Speaker 1: say is that rings could be fairly new. Maybe they're
• 33:21
  Speaker 1: sort of transient. Maybe they come from a cataclysmic event,
• 33:25
  Speaker 1: like something comes in and smashes into a moon or
• 33:27
  Speaker 1: breaks up a moon, and that moon gets shredded into pieces,
• 33:31
  Speaker 1: and maybe it will eventually get gathered back together into
• 33:35
  Speaker 1: a new moon. Right, So these rings might be short
• 33:38
  Speaker 1: lived events in that scenario, like a comet or an
• 33:41
  Speaker 1: asteroid or something else might have created this huge mess.
• 33:45
  Speaker 1: But the Solar System will eventually clean itself up. But
• 33:47
  Speaker 1: if it's in that sweet spot where it's still getting
• 33:51
  Speaker 1: shredded by the planet's gravitational force, but it's not so
• 33:56
  Speaker 1: close that doesn't get sucked into the planet's going to
• 33:59
  Speaker 1: stay a ring, right, it could right, It depends a
• 34:01
  Speaker 1: lot on the details. Like you could have a moon
• 34:03
  Speaker 1: that was past the roche limit, but then an impact
• 34:06
  Speaker 1: creates a huge amount of debris, some of which falls
• 34:08
  Speaker 1: into the sort of the ring zone, some of it
• 34:10
  Speaker 1: could fall into the planet, or some of it could
• 34:12
  Speaker 1: stay out in the sort of moon area and form
• 34:14
  Speaker 1: a new moon. So you're right that you could also
• 34:17
  Speaker 1: form rings, which then can be fairly stable. If you
• 34:20
  Speaker 1: have a collision which creates a lot of mess, and
• 34:22
  Speaker 1: some of that mess is stable in the sort of
• 34:24
  Speaker 1: ring zone, then you could have a long, living ring.
• 34:27
  Speaker 1: That's how I like to describe myself, a stable mess.
• 34:30
  Speaker 1: So that seems really difficult to kind of parse out
• 34:34
  Speaker 1: those theories, I guess without taking a closer look, because
• 34:38
  Speaker 1: stuff that comes crashing into Saturn and stuff that was
• 34:43
  Speaker 1: originally there when Saturn was formed may from a distance
• 34:47
  Speaker 1: look pretty similar unless we keep investigating right exactly, And
• 34:51
  Speaker 1: so to understand where its specific ring comes from, we
• 34:55
  Speaker 1: need to look at that ring in detail, and we
• 34:57
  Speaker 1: need to think about isn't made out of the same
• 34:59
  Speaker 1: stuff as the plan in it or something weird and new?
• 35:01
  Speaker 1: Does it look like it's aged a lot, and does
• 35:04
  Speaker 1: it look like it's a fairly fresh result of a
• 35:06
  Speaker 1: collision or does it look like really weathered from lots
• 35:08
  Speaker 1: of Solar system radiation and collisions. We can also understand
• 35:12
  Speaker 1: the distribution of the rings, like where the mass is
• 35:15
  Speaker 1: in the ring, and build models to see like is
• 35:17
  Speaker 1: it stable, could it hold itself together? Could have developed
• 35:20
  Speaker 1: into this over time? So for each ring, the crucial
• 35:23
  Speaker 1: thing is to get as much information as possible and
• 35:26
  Speaker 1: then to build these models to try to explain what
• 35:28
  Speaker 1: we see, and that will help us discriminate between various scenarios.
• 35:32
  Speaker 1: And a key thing to understand is that it might
• 35:34
  Speaker 1: not be one answer for every ring. It might be
• 35:37
  Speaker 1: there are some rings that are ancient and other rings
• 35:40
  Speaker 1: that are very fresh. What is the difference between what
• 35:42
  Speaker 1: we can tell with like a telescope here on Earth
• 35:46
  Speaker 1: versus something we send out to get a closer look.
• 35:49
  Speaker 1: There's no fundamental difference, right. We can do the same
• 35:52
  Speaker 1: things here as we can do getting close. But of
• 35:54
  Speaker 1: course the closer you get, the better your data. You
• 35:57
  Speaker 1: can resolve these things better just because you're closer up,
• 35:59
  Speaker 1: so you don't need like as big a lens. You
• 36:01
  Speaker 1: can also bring instruments closer up, you know, things like
• 36:04
  Speaker 1: spectrometers to measure these things. There's one thing that you
• 36:07
  Speaker 1: can do by sending a satellite that you can't do
• 36:10
  Speaker 1: from Earth, which is to try to measure the mass
• 36:13
  Speaker 1: of the rings. We'll talk about it when we get
• 36:15
  Speaker 1: into Saturn, when we send Cassini out to Saturn and
• 36:18
  Speaker 1: actually dove in between the rings and the planets and
• 36:22
  Speaker 1: measure the effect of the rings gravity on Cassini itself
• 36:27
  Speaker 1: as a way to measure the mass of the rings.
• 36:29
  Speaker 1: And that's just not something you can do from Earth.
• 36:31
  Speaker 1: That's something that requires perturbing, a gravitationally throwing something out
• 36:36
  Speaker 1: there which is going to actually interact with the mass
• 36:38
  Speaker 1: of the ring itself to see how much stuff there
• 36:41
  Speaker 1: is in there. Is it dangerous for the satellite to
• 36:44
  Speaker 1: be in the rings? Like, is it going to get
• 36:45
  Speaker 1: hit by a bunch of little little space baby? It
• 36:50
  Speaker 1: can be dangerous, But a dove in between in one
• 36:52
  Speaker 1: of the gaps to avoid collisions. Yeah, And you know
• 36:54
  Speaker 1: these things seem smooth, they seem like, oh, it's a
• 36:57
  Speaker 1: continuous blob, but actually there's lots of gaps in between them,
• 37:01
  Speaker 1: so you could fly through the rings and survive, though,
• 37:03
  Speaker 1: you know, it would be a little bit harrowing. I
• 37:05
  Speaker 1: see it, well, brave little satellite, But we don't have
• 37:08
  Speaker 1: any satellites that have like a little extendable ice cream
• 37:12
  Speaker 1: scoop that scoops up some of the stuff in the rings.
• 37:16
  Speaker 1: So how do we know what they're made of? And
• 37:19
  Speaker 1: do we know what they're made of? So we can
• 37:21
  Speaker 1: so we know a little bit about what they're made
• 37:22
  Speaker 1: out of based on our models, you know what's in
• 37:25
  Speaker 1: the Solar system, and also based on our studies of
• 37:28
  Speaker 1: what light reflects off of them. That's really our best
• 37:31
  Speaker 1: way to understand what's in them. Mostly we think that
• 37:34
  Speaker 1: the rings are made out of ice and dust, and
• 37:37
  Speaker 1: that's also you know what the planets are made out of.
• 37:39
  Speaker 1: The Planets when they were forming, were made out of
• 37:41
  Speaker 1: the basic ingredients of the Solar system, which was dust
• 37:44
  Speaker 1: and ice and gas. Now, most of the gas got
• 37:47
  Speaker 1: slurped up by the Sun or by the gas giants themselves,
• 37:51
  Speaker 1: and so you're left over with ice and dust. Now,
• 37:53
  Speaker 1: in the inner Solar system, a lot of that ice
• 37:55
  Speaker 1: is vaporized. But in the outer Solar system, past what
• 37:58
  Speaker 1: we call the frost line, it was cold enough for
• 38:01
  Speaker 1: that ice to stay solid, and so it helped form
• 38:04
  Speaker 1: some of these ice giants, And so the rings are
• 38:06
  Speaker 1: made out of that same stuff, mostly ice and dust.
• 38:09
  Speaker 1: Beyond the frost line, there's a lot of ice in them.
• 38:11
  Speaker 1: Saturn's rings, for example, are mostly icy particles in closes ring.
• 38:15
  Speaker 1: You expect more rock and dust in rings. So when
• 38:18
  Speaker 1: we're talking about ice, you know, I think of I
• 38:20
  Speaker 1: mean especially today because it's so hot, but I think
• 38:22
  Speaker 1: of a big chunk of ice that I would put
• 38:25
  Speaker 1: in my drink, like in my glass. But is that
• 38:28
  Speaker 1: what this ice is? Are they big chunks? Is it
• 38:31
  Speaker 1: sort of like ice crystals and a bunch of them?
• 38:34
  Speaker 1: What form does this ice take? So when we're talking
• 38:37
  Speaker 1: about ice, we do mean water ice. This is like
• 38:40
  Speaker 1: h duo. But there's also other kinds of ice, you know,
• 38:42
  Speaker 1: ammonia ice and other kinds of things. So when chemists
• 38:45
  Speaker 1: say ice, they mean a wide range of stuff, not
• 38:49
  Speaker 1: just the stuff you put in your summer cocktails. But
• 38:51
  Speaker 1: it does include you know, drinkable water ice, like if
• 38:55
  Speaker 1: you are building a colony around Saturn and you need water,
• 38:58
  Speaker 1: like the rings are a great source of water the
• 39:01
  Speaker 1: humans could actually drink and it comes in chunks. You know.
• 39:04
  Speaker 1: Some of these things are as small as a centimeter,
• 39:06
  Speaker 1: like cute little ice cubes that would fit in your glass.
• 39:10
  Speaker 1: And some of them are like are as big as
• 39:11
  Speaker 1: ten meters, so you know, like really pretty big chunks.
• 39:15
  Speaker 1: You'd have to be a giant to enjoy that in
• 39:17
  Speaker 1: your limited So I couldn't theory right that satellite hold
• 39:21
  Speaker 1: out a glass eliminated and get some ice in there.
• 39:23
  Speaker 1: As long as I don't get pulverized by a giant
• 39:26
  Speaker 1: ice chunk, that's great news. What's the dust made out of?
• 39:30
  Speaker 1: So the dust is just you know, silicates, it's like rock,
• 39:33
  Speaker 1: the same kind of stuff that the Earth is made
• 39:35
  Speaker 1: out of. Like it's just basically dirt, you know, huge
• 39:37
  Speaker 1: chunks of rock and dirt. And some of these things
• 39:40
  Speaker 1: have organic compounds in them, you know. We wonder about
• 39:43
  Speaker 1: like the formation of life whatever. The interesting area of
• 39:46
  Speaker 1: research is like where do organic molecules come from the
• 39:49
  Speaker 1: basic building blocks of life? Are they only found on
• 39:52
  Speaker 1: Earth or are they found all over the universe? So
• 39:55
  Speaker 1: looking at the rings helps us understand that kind of thing.
• 39:57
  Speaker 1: We also study asteroids and comets and we find is
• 40:00
  Speaker 1: that there are organic compounds all over the Solar system.
• 40:04
  Speaker 1: These basic building blocks are not rare, They're everywhere. So
• 40:08
  Speaker 1: you've got ice, which is, you know, the solid form
• 40:11
  Speaker 1: of water, and you've got organic compounds. Is there a
• 40:14
  Speaker 1: reason why we wouldn't expect there to be life on Saturn?
• 40:18
  Speaker 1: Is it because the ice would be solid? Or is
• 40:21
  Speaker 1: it because Saturn's surface is not hospitable to the formation
• 40:25
  Speaker 1: of life. I don't know if there's life on Satura.
• 40:27
  Speaker 1: And of course, if there is, life on Saturday would
• 40:30
  Speaker 1: have to be quite different from life on Earth because
• 40:33
  Speaker 1: the environment on Saturday is very different. Right Saturday is
• 40:36
  Speaker 1: a gas giant and so it's very high pressure. There's
• 40:39
  Speaker 1: a lot of radiation on Saturn, so it would have
• 40:42
  Speaker 1: to be quite different. But one of the moons of Saturn, Insulatus,
• 40:45
  Speaker 1: which we've talked about, has an icy shell, and underneath
• 40:49
  Speaker 1: is a liquid ocean, and that liquid ocean is partially
• 40:53
  Speaker 1: kept liquid by those tidal forces. Saturny is squeezing that moon,
• 40:57
  Speaker 1: which keeps it from freezing. It's imparting energy to it,
• 41:00
  Speaker 1: sort of like by massaging it with its gravity. So
• 41:03
  Speaker 1: in the water under the surface of Ensilatus might be
• 41:08
  Speaker 1: some life. We just don't know, but the rings are
• 41:11
  Speaker 1: mostly frozen. They're mostly just big chunks of ice. And
• 41:14
  Speaker 1: you know, there's a fascinating sort of geometrical structure here
• 41:17
  Speaker 1: because they are very, very wide. You know, these things
• 41:21
  Speaker 1: are like seventy two hundred thousand kilometers wide. We're talking
• 41:25
  Speaker 1: about Saturn's rings, but in terms of thickness, they're like
• 41:28
  Speaker 1: twenty meters thick. So there are tens of thousands of
• 41:32
  Speaker 1: kilometers wide and only tens of meters thick. If you
• 41:35
  Speaker 1: had a sheet of paper of this thickness, they would
• 41:38
  Speaker 1: have to be like a kilometer wide sheet of paper
• 41:41
  Speaker 1: to have the same proportions as Saturn's rings. That's an
• 41:44
  Speaker 1: idea for your science project, elementary schoolers, a model of
• 41:49
  Speaker 1: Saturn's rings. And you know, you can see Saturn's rings
• 41:52
  Speaker 1: from Earth, which is incredible without a really powerful telescope.
• 41:55
  Speaker 1: But there's a lot more rings to Saturn than you
• 41:57
  Speaker 1: can just see. There's three really bright ring which astronomers
• 42:00
  Speaker 1: have cleverly named A, B, and C, of course, but
• 42:04
  Speaker 1: there are other rings that go out even further out
• 42:07
  Speaker 1: to the G ring and the E ring, and these
• 42:09
  Speaker 1: go out like past three to nine times the radius
• 42:13
  Speaker 1: of Saturn itself, So like the volume of Saturn is
• 42:17
  Speaker 1: dominated by these rings. It's like the biggest thing in
• 42:20
  Speaker 1: the Saturn system. That's really interesting. So how many rings
• 42:24
  Speaker 1: are there total? Denal, Well, there are rings out to
• 42:27
  Speaker 1: G rings and the rings right and so there are
• 42:29
  Speaker 1: like dozens of these rings. And it depends a little
• 42:31
  Speaker 1: bit on how you count, because each of the rings
• 42:33
  Speaker 1: can be subdivided into like sub rings. And some of
• 42:37
  Speaker 1: these rings that have there are these gaps between them
• 42:39
  Speaker 1: which are maintained by these little shepherd moons. So you
• 42:43
  Speaker 1: have these little moonlits which are strong enough to survive
• 42:46
  Speaker 1: inside the roche limit. Remember the rocial limit not a
• 42:48
  Speaker 1: hard and fast rule, depending on what you're made out of.
• 42:51
  Speaker 1: So if you're a small enough moon and you made
• 42:53
  Speaker 1: have a really tough stuff and you can survive in
• 42:55
  Speaker 1: the ring system and you sort of perturb the rings,
• 42:58
  Speaker 1: you can like keep the rings from mixing with each other.
• 43:01
  Speaker 1: So a lot of these gaps are because there's a moon.
• 43:04
  Speaker 1: They are a little moonlit that's keeping them apart, a
• 43:06
  Speaker 1: little hall monitor moon that's adorable exactly, and it keeps
• 43:10
  Speaker 1: them having the like really crisply sharply defined edges. It
• 43:14
  Speaker 1: seems like there's a bunch of mass and these rings,
• 43:17
  Speaker 1: how do we know that, like Saturn's gravity is strong
• 43:22
  Speaker 1: enough to keep them in that sort of sweet spot
• 43:26
  Speaker 1: of staying rings and not drifting out or forming moons.
• 43:30
  Speaker 1: So we didn't know until pretty recently how much mass
• 43:32
  Speaker 1: there was. You knew we could see it, but we
• 43:34
  Speaker 1: didn't really know like how much stuff is there is
• 43:37
  Speaker 1: equivalent to a moon? Is it like thousand times and moons?
• 43:39
  Speaker 1: It much less than a moon of Saturn. And so
• 43:41
  Speaker 1: it was when Cassini went up there and it passed
• 43:43
  Speaker 1: between these rings that it gave us a measurement for
• 43:46
  Speaker 1: how much mass there is. And what we discovered was
• 43:49
  Speaker 1: that the rings had sort of surprisingly low mass. We
• 43:52
  Speaker 1: expected them to have some more mass, to be like
• 43:54
  Speaker 1: more substantial, but they're really sort of like light and fluffy.
• 43:58
  Speaker 1: The other thing that's really interesting for Cassini is that
• 44:00
  Speaker 1: we got these very close up pictures of what these
• 44:03
  Speaker 1: rings were made out of, and scientists were surprised to
• 44:05
  Speaker 1: see that the components of the rings were still sort
• 44:08
  Speaker 1: of sharp, you know, they have like crisp edges to them.
• 44:11
  Speaker 1: They're really quite reflective compared to what we expected if
• 44:14
  Speaker 1: these rings were ancient. If they've been there for a
• 44:17
  Speaker 1: long long time, you would expect them to bump into
• 44:20
  Speaker 1: each other. Things eventually get rounded. All the radiation from
• 44:23
  Speaker 1: Saturn would have weathered them a little bit. That gives
• 44:25
  Speaker 1: people the impression that maybe these things are quite new. Right,
• 44:29
  Speaker 1: If you add up all the mass of these rings,
• 44:31
  Speaker 1: it's just about the mass of a typical moon of Saturn,
• 44:34
  Speaker 1: which is very suggestive. It says maybe this was once
• 44:37
  Speaker 1: a moon of Saturn. Maybe one of the moons of
• 44:40
  Speaker 1: Saturn got smashed up in a collision, they bounced into
• 44:43
  Speaker 1: each other, or something came into the Solar system and
• 44:45
  Speaker 1: destroyed a moon of Saturn and created this big mess
• 44:49
  Speaker 1: which then fell into the Roche limit and became the
• 44:52
  Speaker 1: rings of Saturn. It's a theory. We just don't know,
• 44:55
  Speaker 1: but it's one speculation. So if when you're saying these
• 44:58
  Speaker 1: are relatively new, what do you mean by that? Because
• 45:01
  Speaker 1: I've learned that when you say new in terms of
• 45:04
  Speaker 1: the Solar System or the universe, it means very old exactly.
• 45:09
  Speaker 1: It means new on a universe time scale. So we're
• 45:12
  Speaker 1: talking like maybe in the last hundred million years, whereas
• 45:16
  Speaker 1: the Solar system is four and a half billion years
• 45:19
  Speaker 1: old if you're forty five, for example, saying you had
• 45:22
  Speaker 1: a ring in the last year or so makes it
• 45:24
  Speaker 1: feel sort of new, right, Yeah, I mean my ring
• 45:27
  Speaker 1: feels still pretty new even though it's about a year old.
• 45:31
  Speaker 1: But yes, so that is really interesting. Do you think
• 45:36
  Speaker 1: these rings around Saturn are permanent? Well, we don't know
• 45:39
  Speaker 1: how long they are going to last. If they're fairly new,
• 45:42
  Speaker 1: it suggests that they might not. They might be like
• 45:44
  Speaker 1: falling into Saturn. Saturn might be losing its moods as
• 45:48
  Speaker 1: its gravity pulls these little bits into it. Or they
• 45:51
  Speaker 1: could also be quite stable, right, even if they are new,
• 45:54
  Speaker 1: they could still be stable if they ended up in
• 45:55
  Speaker 1: the right spot, if they're within the roche limit. So
• 45:58
  Speaker 1: in order to understand that whether it's and it's going
• 46:00
  Speaker 1: to keep its rings, we need to understand some of
• 46:02
  Speaker 1: the process is going on there, like is Saturn gathering
• 46:05
  Speaker 1: these things up? Are things falling into Saturn or not.
• 46:08
  Speaker 1: We also need to understand like whether there are new
• 46:10
  Speaker 1: sources for these rings. That same moon we talked about
• 46:14
  Speaker 1: insult Us also has geysers on it, so like cracks
• 46:17
  Speaker 1: in those oceans shoot water out into space, constantly, and
• 46:22
  Speaker 1: this is new material for rings, as those newly formed
• 46:25
  Speaker 1: crystals in space gets sucked in by Saturn's gravity. So
• 46:28
  Speaker 1: there's a really far out ring called the E ring,
• 46:31
  Speaker 1: which probably is being constantly replenished by geysers from one
• 46:36
  Speaker 1: of Saturn's moons. Well, that's interesting. So you've got like
• 46:39
  Speaker 1: a sprinkler system that is keeping these rings alive. Well,
• 46:44
  Speaker 1: I hope Saturn has a sense of commitment so keeps
• 46:47
  Speaker 1: that ring for our benefit because it is so pretty
• 46:50
  Speaker 1: to look at. But I'm also curious why Saturn is
• 46:55
  Speaker 1: so unique in its rings in the Solar System, or
• 46:58
  Speaker 1: whether it is unique. But first I need to take
• 47:01
  Speaker 1: a break, and I'm gonna do a little hula hooping
• 47:05
  Speaker 1: so I can feel more like I am saturned, so
• 47:09
  Speaker 1: I can visualize what it's like to be saturned. And
• 47:25
  Speaker 1: we're back after an exhausting five minutes of me hula hooping.
• 47:29
  Speaker 1: Remind me never to do that again. But I was
• 47:32
  Speaker 1: asking before the break, is Saturn unique in the Solar
• 47:37
  Speaker 1: System in terms of its rings and why is it unique?
• 47:39
  Speaker 1: Because it seems like it at least has the most
• 47:43
  Speaker 1: spectacular rings in the Solar System. It definitely has the
• 47:46
  Speaker 1: most spectacular rings and the most obvious from Earth, but
• 47:49
  Speaker 1: it turns out it's actually not unique, and that there
• 47:51
  Speaker 1: are rings all over the Solar System, and there are
• 47:54
  Speaker 1: rings that might be right in our backyard and in
• 47:57
  Speaker 1: our future. When you look up at more Cars, which
• 48:00
  Speaker 1: is one of our neighboring planets, you don't see rings
• 48:03
  Speaker 1: on it. But that might be different in about thirty
• 48:05
  Speaker 1: two fifty million years, because Mars is in the process
• 48:09
  Speaker 1: of pulling apart its moons and shredding them, so they
• 48:12
  Speaker 1: eventually might turn into rings. So physicists out there, I
• 48:16
  Speaker 1: want to give you some advice. If you are in
• 48:18
  Speaker 1: a relationship and you tell your partner, I see a
• 48:22
  Speaker 1: ring in our future, just before warned that they may
• 48:25
  Speaker 1: not know you're talking about Mars, and that you've got
• 48:30
  Speaker 1: to wait quite a while. You know, we're talking about
• 48:33
  Speaker 1: tens of millions of years, and Mars is a really
• 48:36
  Speaker 1: fascinating case because it might sort of up end this clear,
• 48:40
  Speaker 1: crisp difference between rings and moons a little bit. I
• 48:42
  Speaker 1: read a recent paper that suggests that it might be
• 48:45
  Speaker 1: in the middle of a ring moon cycle. Then it
• 48:48
  Speaker 1: might be forming moons which then get shredded into rings.
• 48:51
  Speaker 1: Which then get formed back into moons. So it could
• 48:54
  Speaker 1: be like slashing back and forth between ringed and mooned
• 48:57
  Speaker 1: and ringed and mooned. That's interesting, I do you know
• 49:00
  Speaker 1: some people like that. But so how does it If
• 49:04
  Speaker 1: it keeps shifting back and forth, that must mean that
• 49:07
  Speaker 1: this roche limit is not always stable. What makes it unstable? Well,
• 49:11
  Speaker 1: it depends again on how strong this thing is, the
• 49:14
  Speaker 1: structural integrity of the object, and exactly where it is.
• 49:18
  Speaker 1: The idea here is you have a giant impact, and
• 49:20
  Speaker 1: this giant impact doesn't just create a big spray of
• 49:23
  Speaker 1: debris which can form into rings and moons, but it
• 49:26
  Speaker 1: can also actually change the gravitational field of the planet itself,
• 49:30
  Speaker 1: so like exactly where the roche limit is can change.
• 49:33
  Speaker 1: So you can have, for example, the formation of a moon,
• 49:36
  Speaker 1: which can last for a little while, but then as
• 49:39
  Speaker 1: the planet itself settles back down, you know, part of
• 49:41
  Speaker 1: this debris then falls back onto the planet, it can
• 49:44
  Speaker 1: change where the roche limit is. So the moon forms
• 49:47
  Speaker 1: when the rocial limits in one place, but then as
• 49:50
  Speaker 1: the stuff settles in and some of it falls onto
• 49:52
  Speaker 1: the planet, the rochial limit shifts, and so the moons
• 49:55
  Speaker 1: can then be torn apart. Some of that stuff might
• 49:57
  Speaker 1: fall down to the planet, some of it might former ring,
• 50:00
  Speaker 1: some of it might like form like a half moon
• 50:02
  Speaker 1: which gets pushed out even further. So we're talking about Mars'
• 50:06
  Speaker 1: potential future here and potential past. But you also mentioned
• 50:10
  Speaker 1: that there are a lot of rings in the Solar
• 50:12
  Speaker 1: system currently, right, There are a lot of rings in
• 50:15
  Speaker 1: the Solar System exactly. So Jupiter, for example, also has rings.
• 50:19
  Speaker 1: These are interesting because they're one of the first ones
• 50:21
  Speaker 1: discovered by a satellite. Like it's very hard to see
• 50:24
  Speaker 1: Jupiter's rings from Earth, even with a very very powerful telescope,
• 50:29
  Speaker 1: and so these were discovered in seventy nine by voyage
• 50:32
  Speaker 1: of one And the reason that they're hard to see
• 50:34
  Speaker 1: is that they're very faint and it consists mostly of dust,
• 50:37
  Speaker 1: and people think that they're probably just constantly created by
• 50:41
  Speaker 1: micro meteorites hitting the planets moons. Remember, Jupiter is very
• 50:45
  Speaker 1: very massive and it's very strong gravity, so it's likely
• 50:48
  Speaker 1: just like suck a lot of this stuff up. But
• 50:50
  Speaker 1: they think that there's like a constant replenishment of this
• 50:53
  Speaker 1: stuff as things hit the Moon create this like debris
• 50:56
  Speaker 1: which forms sort of a temporary ring around Jupiter, which
• 50:59
  Speaker 1: eventually falls back into Jupiter. So Jupiter's gravity is so
• 51:03
  Speaker 1: strong that doesn't really have a chance to accumulate a
• 51:05
  Speaker 1: ring that lasts very long. You mentioned that it's harder
• 51:08
  Speaker 1: to see it because it's mainly made out of dust.
• 51:11
  Speaker 1: What makes ice more visible? Ice is just shiny or like,
• 51:14
  Speaker 1: it's just basic chemistry. You shine a light on a
• 51:16
  Speaker 1: piece of ice, it's going to reflect more than a
• 51:18
  Speaker 1: rock will. Right, So ice is just brighter and wider.
• 51:22
  Speaker 1: I guess that's why we call diamonds ice. That makes fun.
• 51:26
  Speaker 1: And Jupiter also, remember, is not just gravitationally powerful. It
• 51:29
  Speaker 1: has very strong magnetic fields and radiation, and so the
• 51:32
  Speaker 1: electromagnetic forces interact with these dust particles moving around Jupiter,
• 51:37
  Speaker 1: and it means that it's hard for these things to
• 51:39
  Speaker 1: orbit Jupiter for more than like a hundred or a
• 51:41
  Speaker 1: thousand years. And so for Jupiter to have a ring
• 51:44
  Speaker 1: system at any point that lasts more than you know,
• 51:47
  Speaker 1: a hundred or a thousand years, means it needs a
• 51:49
  Speaker 1: constant source of replenishment. That's why this theory that micro
• 51:52
  Speaker 1: meteorites are creating dust constantly to sort of feed Jupiter's
• 51:56
  Speaker 1: ring system. I see, so Jupiter is just too hungry
• 52:00
  Speaker 1: to maintain that ring without having some of those micro
• 52:05
  Speaker 1: collisions spewing out more debris. Is Jupiter the only other
• 52:09
  Speaker 1: planet that has rings. No Neptune also has rings. These
• 52:13
  Speaker 1: are really fascinating, the Air five rings, but they're sort
• 52:16
  Speaker 1: of the reverse of Saturn. Instead of being mostly ice,
• 52:18
  Speaker 1: they're actually mostly dark particles and they're confined to a
• 52:22
  Speaker 1: few little narrow rings, and they're really interesting because they're
• 52:25
  Speaker 1: not the same all the way around. It's not like
• 52:28
  Speaker 1: Saturn that has this symmetry to have these like bright
• 52:30
  Speaker 1: arcs and then these empty gaps between them, so it's
• 52:33
  Speaker 1: really kind of weird. So these like broken rings around Saturn, yeah, exactly.
• 52:39
  Speaker 1: And people think that maybe there are moons. They're like
• 52:41
  Speaker 1: little shepherd moons that are interfering with these rings and
• 52:44
  Speaker 1: causing this structure, but we haven't been able to see
• 52:46
  Speaker 1: them because our telescopes aren't powerful enough yet. And Urine
• 52:49
  Speaker 1: is also has rings. These rings are really strange because
• 52:52
  Speaker 1: they're almost totally black. They're like lumps of coal, so
• 52:57
  Speaker 1: they think they might be like carbon and hydrocarbon, but
• 53:00
  Speaker 1: they're just not sure. So we really need are like
• 53:02
  Speaker 1: more exploration of the outer Solar system to understand these
• 53:06
  Speaker 1: rings and the role they play in the history of
• 53:08
  Speaker 1: these planets. I like that Urineus is going for a
• 53:11
  Speaker 1: golf look that is bringing Goth back. I don't know
• 53:14
  Speaker 1: if it ever left. So our solar system has a
• 53:18
  Speaker 1: good number of rings. But we talked about at the
• 53:21
  Speaker 1: beginning whether we are unique as a solar system, whether
• 53:25
  Speaker 1: we can find rings outside of our solar system. Is
• 53:29
  Speaker 1: there any evidence of rings uh far and wide. So
• 53:33
  Speaker 1: scientists think that it's very plausible that other planets might
• 53:37
  Speaker 1: have rings, just because they're not that unusual in our
• 53:39
  Speaker 1: solar system. As you can hear, they're like basically everywhere
• 53:42
  Speaker 1: you know, Saturn, Jupiter, Urinous, Neptune, even Mars might eventually
• 53:46
  Speaker 1: have rings. So we suspect that just from that data,
• 53:50
  Speaker 1: they should be in other solar systems. But of course
• 53:52
  Speaker 1: we want to see it and to know. We don't
• 53:54
  Speaker 1: just want to speculate about the nature of the universe.
• 53:56
  Speaker 1: And so what we can do is look for rings
• 53:59
  Speaker 1: around planet's in much the same way that we look
• 54:01
  Speaker 1: for the planets themselves. The way we detect planets around
• 54:05
  Speaker 1: other stars, or one way at least, is the transit method.
• 54:08
  Speaker 1: The planet passes in front of its star like a
• 54:10
  Speaker 1: little mini eclipse and dims the light of that star
• 54:14
  Speaker 1: a little bit. That's how we know the planet is there.
• 54:16
  Speaker 1: How can we see rings around it? Well? From the
• 54:19
  Speaker 1: transit method, we can also get a sense of the
• 54:21
  Speaker 1: size of the planet and its mass. So we get
• 54:24
  Speaker 1: a sense of the size because of how much light
• 54:27
  Speaker 1: is blocked from the star. We get a sense of
• 54:29
  Speaker 1: its mass because we can measure its orbit. And so
• 54:31
  Speaker 1: if the planet seems to be really really large, there's
• 54:35
  Speaker 1: like this extra reduction in the light of the star
• 54:37
  Speaker 1: because it has like big fluffy things around it, that
• 54:41
  Speaker 1: might be evidence for rings around the planet. If it
• 54:44
  Speaker 1: seems like bigger than we would otherwise understand it to be.
• 54:47
  Speaker 1: It seems like bigger than we would otherwise expect it
• 54:50
  Speaker 1: to be from its mass and from its orbit. I see.
• 54:52
  Speaker 1: So if the orbit doesn't match how fluffy it looks,
• 54:56
  Speaker 1: how much light it blocks, that may be a sign
• 54:59
  Speaker 1: of a ring. Could it be something else instead of
• 55:02
  Speaker 1: a ring, like we mentioned, just having a bunch of
• 55:05
  Speaker 1: junk kind of floating around the planet in not ring form.
• 55:09
  Speaker 1: I mean, it could be like a lot of moons.
• 55:11
  Speaker 1: I suppose one candidate is this planet h I p
• 55:15
  Speaker 1: S eight F, which looks like it has a really
• 55:19
  Speaker 1: really huge radius, like nine times the radius of the Earth.
• 55:22
  Speaker 1: So either it's like a big styrofoam planet hardly filled
• 55:25
  Speaker 1: with anything, or it's a planet with an extensive ring
• 55:28
  Speaker 1: system that's blocking all of that light. And that's really
• 55:31
  Speaker 1: the only thing we can really think of. Is another planet,
• 55:33
  Speaker 1: Proxima Centauri C, which is a planet orbiting our immediate
• 55:37
  Speaker 1: neighbor Proximus Centauri. It has seven times the mass of
• 55:40
  Speaker 1: the Earth, but it's sort of weirdly bright and reflective,
• 55:44
  Speaker 1: which makes people think like perhaps it's surrounded by icy rings.
• 55:48
  Speaker 1: But as you can maybe get a sense for this
• 55:49
  Speaker 1: is very uncertain stuff. We're only just recently been able
• 55:53
  Speaker 1: to detect exo planets. We're getting better and better at it,
• 55:56
  Speaker 1: and soon we'll be doing things like studying the atmosphere
• 55:58
  Speaker 1: of exo planets, and this is sort of on that
• 56:01
  Speaker 1: list of things we're just beginning to be able to do.
• 56:03
  Speaker 1: It's kind of like physicists need to start to catch
• 56:07
  Speaker 1: up with jewelers, who can look at rings by using
• 56:11
  Speaker 1: a magnifying glass to see things really really tiny, but
• 56:15
  Speaker 1: physicists have to investigate their rings by looking at things
• 56:20
  Speaker 1: really really far away and blowing them up as much
• 56:22
  Speaker 1: as they can. Absolutely, and I expect that some of
• 56:25
  Speaker 1: those solar systems may have spectacular ring systems. I suspect
• 56:29
  Speaker 1: that when we get really nice images of them, you know,
• 56:31
  Speaker 1: if maybe from James Web or from the next generation
• 56:34
  Speaker 1: of space telescopes, we'll see things that blow our minds,
• 56:37
  Speaker 1: that make scientists say, what, that's impossible. You can't have
• 56:40
  Speaker 1: rings like that. That breaks all of our understandings. And
• 56:43
  Speaker 1: breaking our understanding is exactly the moment to learn about
• 56:46
  Speaker 1: the universe, to say, oh, well, it turns out we
• 56:49
  Speaker 1: didn't understand this as well as we thought we did.
• 56:51
  Speaker 1: We got to change our models. We have to add
• 56:53
  Speaker 1: something new to it, or develop some new idea for
• 56:56
  Speaker 1: how these things can form. And that's the exciting thing.
• 56:59
  Speaker 1: It's like opening a new book and being surprised by
• 57:02
  Speaker 1: what you find in Every one of these solar systems
• 57:05
  Speaker 1: will have surprises for us, things that we probably can't
• 57:08
  Speaker 1: imagine today. And isn't that the dream of every planetary
• 57:11
  Speaker 1: fashionista to wear rings so spectacular it makes scientists scratch
• 57:17
  Speaker 1: their heads and throw away all their textbooks. Exactly so
• 57:21
  Speaker 1: from Rings down here on Earth, wowing all of your friends,
• 57:25
  Speaker 1: two rings around the planets themselves, telling us something about
• 57:28
  Speaker 1: how those planets formed, and something about their history and
• 57:31
  Speaker 1: something about their future. Rings have a lot to tell
• 57:34
  Speaker 1: us about the nature of our lives, all right, Thanks
• 57:37
  Speaker 1: very much Katie for joining us on today's episode about Rings.
• 57:41
  Speaker 1: Was a lot of fun and we hope you all
• 57:43
  Speaker 1: ring in a wonderful day. Thank you very much for
• 57:46
  Speaker 1: listening and tune in next time. Hi, thanks for having me,
• 57:57
  Speaker 1: Thanks for listening, and remember that Daniel and Jorge Explain
• 58:00
  Speaker 1: in the Universe is a production of I Heart Radio
• 58:02
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• 58:05
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• 58:09
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