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Speaker 1: Hey, Katie, how do you like your gelato? Definitely with

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Speaker 1: two scoops of basically any flavor. So it's all about

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Speaker 1: quantity for you, that right, It's all about gelato. What's

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Speaker 1: to complain about? All right? So is that also true

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Speaker 1: for things out in space? Bigger is always better? I mean,

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Speaker 1: the sun is gigantic, and I only have good things

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Speaker 1: to say about that. So you know, all right, you

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Speaker 1: should leave a five star review for our star? What

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Speaker 1: about things like comets? Is bigger always better there? I mean,

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Speaker 1: especially if they're made out of ice cream? So a

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Speaker 1: big old comet streaking above our sky leaving a trail

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Speaker 1: of sprinkles? Who doesn't want that? Well? What if it's

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Speaker 1: sprinkling its way towards the earth like impact style? Well

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Speaker 1: then I can order a triple gelato with no consequences. Hi.

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Speaker 1: I'm Daniel. I'm a particle physicist and a professor at

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Speaker 1: U C Irvine, and I am Katie, and I'm the

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Speaker 1: host of the podcast Creature Feature. And I enjoy ice

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Speaker 1: cream as much as I enjoy physics, which is a

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Speaker 1: lot but not too much moderation in all things? Is

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Speaker 1: that the vibe I'm getting? That's probably right? In both cases,

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Speaker 1: if I have too much physics at once, I also

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Speaker 1: get a brain freeze. Or did you mean like after

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Speaker 1: a nice large meal you need a little bit of

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Speaker 1: physics to sort of like balance out the palette. I mean,

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Speaker 1: I think that's what digestion is, right, Absolutely well, Welcome

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Speaker 1: to the podcast Daniel and Jorge explain the universe in

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Speaker 1: which we try to digest the entire universe. We serve

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Speaker 1: it up on a platter d you and give it

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Speaker 1: to you in tiny little spoonfuls, hoping that helps you

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Speaker 1: understand the mysteries of black holes, the incredible froth and

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Speaker 1: quantum nature of reality, the mysteries, the puzzles, the insides,

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Speaker 1: all of it. We sprinkle delicious treats on top and

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Speaker 1: serve it up to you. It's the Moves Bouge of

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Speaker 1: particle physics. My typical co host and friend, Jorge Champ

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Speaker 1: can't be here today, so as usual we are joined

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Speaker 1: by the wonderful Katie. Katie, thank you very much for

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Speaker 1: joining us again today. Yeah, happy to be here again.

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Speaker 1: Want to point out Jorge and I have never been

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Speaker 1: seen together in the same room. Raises some questions, doesn't it?

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Speaker 1: Does that mean that Jorge transforms into you or you

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Speaker 1: transform into Jorge. At this point, who can say who

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Speaker 1: is who Isn't that the lesson of jack Bile and

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Speaker 1: Hide exactly the quantum mechanical interpretation of modern literature. It's

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Speaker 1: really the jackal Hide wave function, that's right, got to

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Speaker 1: collapse the wave form. Well, we are happy to talk

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Speaker 1: physics with either Katie or Jorge, so thanks for joining us.

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Speaker 1: And while we nibble on our gelato, we ponder the

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Speaker 1: mysteries of the universe, but we also ponder the mysteries

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Speaker 1: of our own neighborhood. You might think that astronomers have

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Speaker 1: our backyard the Solar system, mostly figured out, and that

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Speaker 1: the open questions in physics revolve around things very very

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Speaker 1: far away and far in the future and far back

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Speaker 1: in time. But you might be surprised to learn that

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Speaker 1: our own neighborhood remains something of a mystery to us. Now,

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Speaker 1: that doesn't seem right, because my understanding as we've already

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Speaker 1: got real estate on Mars and have every crevice, every

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Speaker 1: crater of the Moon mapped out, So how can there

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Speaker 1: be any mysteries left here in our solar system? Well,

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Speaker 1: it's probably true that some entrepreneur has planned the first

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Speaker 1: gelato stand on Mars that's pretty close to Earth. And

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Speaker 1: you know, the Solar System is actually really really vast.

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Speaker 1: The Earth is tucked in really tightly, very close to

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Speaker 1: the Sun, but outpassed Jupiter and outpassed the icy planets.

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Speaker 1: There's a lot of mysterious stuff going on. What's the

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Speaker 1: furthest we've ever sent any of our instruments out into space.

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Speaker 1: We haven't gotten past our own Solar System. We have

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Speaker 1: sent some probs really deep into space, just like launch

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Speaker 1: them out there and see how long they last. And

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Speaker 1: the one that's the furthest out the object the humans

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Speaker 1: have built that has gone the deepest into space is

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Speaker 1: Voyager one. But even Voyager one hasn't officially left the

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Speaker 1: Solar System yet. In around three hundred years, it might

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Speaker 1: reach the outskirts of the Solar System, but unfortunately it's

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Speaker 1: power runs out in five so by the time it

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Speaker 1: gets there, it'll just be a dead lump. Well so

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Speaker 1: we so, you know, you'll be fifty gelato by that point. Anyway,

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Speaker 1: I can only hope. So there could be some space

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Speaker 1: gopers in our space backyard and we wouldn't even know it.

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Speaker 1: That's right. There are mysteries right here in our own backyard.

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Speaker 1: There are things we do not understand. One way to

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Speaker 1: explore the mist to send probes deep into the outskirts

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Speaker 1: of the Solar System. But that's pretty slow. You know,

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Speaker 1: it takes years for things to get out there because

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Speaker 1: it's so day far away. You know, it takes months

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Speaker 1: to get to Venus or Mars, but to get out

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Speaker 1: to Pluto can take a decade. To get further out

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Speaker 1: deep into the farthest reaches of the Solar System to

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Speaker 1: explore its fringes takes even longer. But there's another way

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Speaker 1: to study our deep, mysterious backyard, and that's to wait

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Speaker 1: for it to come to us. Because sometimes things out

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Speaker 1: from the outskirts do fall into the Solar System, and

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Speaker 1: these things are called comets. They accelerate to incredible speeds

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Speaker 1: as they whip around the Sun and then go back

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Speaker 1: to where they came from. So how do comets find us?

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Speaker 1: Did they see some kind of flyer way out in

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Speaker 1: space It at the Earth sale about two point five

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Speaker 1: light years away? Is it just random chance? Are they

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Speaker 1: drawn into our Solar system? They hang out there in

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Speaker 1: the deep reaches of the Solar System, and we're not

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Speaker 1: exactly sure what sometimes triggers them to fall in. It

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Speaker 1: might be the passing of a nearby star, or the

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Speaker 1: gravitational tug of the Milky Way, or something else. Entirely,

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Speaker 1: we don't even really understand what's going on out there

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Speaker 1: and what is out there waiting to maybe fall into

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Speaker 1: the Solar System. For those of you who have seen

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Speaker 1: don't look up and worry about things hitting the Earth.

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Speaker 1: You don't have to worry too much about things like asteroids,

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Speaker 1: those rocks that are orbiting the inner Solar system. But

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Speaker 1: comets are much more dangerous because they can be hard

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Speaker 1: to predict, and they're moving much more quickly when they

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Speaker 1: do enter the Solar System. I watched Don't Look Up,

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Speaker 1: and I find it interesting because I think there is

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Speaker 1: a big divide in terms of how realistic people find

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Speaker 1: it in Those who are either climate scientists or even

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Speaker 1: in any related science find it very realistic, whereas other

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Speaker 1: people think, oh, this this is just two on the nose,

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Speaker 1: it's too outrageous. You mean, like the social response to

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Speaker 1: the scientific warning, or you mean the science itself, the

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Speaker 1: social response to the scientific warning that's in the movie. Yeah,

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Speaker 1: that was pretty sobering. Actually, I think that was mostly

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Speaker 1: the point of the movie. The actual science a bit

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Speaker 1: where they're like at the white board figuring out the

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Speaker 1: trajectory of the comment. That was like the first two

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Speaker 1: minutes of the movie. After that, there was a great

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Speaker 1: much science, But that part was pretty accurate. You know though,

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Speaker 1: I heard that they had to find somebody to play

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Speaker 1: a math double for Leonardo DiCaprio. When they zoom in

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Speaker 1: on the whiteboard, that's not actually his hand doing those calculations,

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Speaker 1: which means there's a whole other career. I didn't even

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Speaker 1: realize I was missing out on, you know, Hollywood math double.

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Speaker 1: Who do you think you would be in terms of

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Speaker 1: Hollywood's math double. I'd like to be Jeff Goldblum's math double.

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Speaker 1: I want to do his math. Jeff, if you're listening,

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Speaker 1: please hooking me up. I don't want you to hurt

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Speaker 1: yourself doing maths, so please let me take the fall

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Speaker 1: for you. But speaking of taking the falls, some of

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Speaker 1: these comets that enter the Solar System are pretty small.

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Speaker 1: There's just a few kilometers wide. But there's some been

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Speaker 1: some recent discoveries that are stretching people's brains about how

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Speaker 1: big a comet can be. So you're saying that asteroids

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Speaker 1: are not typically that dangerous whereas comets are. Why is

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Speaker 1: that is that base stun the stuff that they're made

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Speaker 1: out of, or their behaviors. It's mostly based on our

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Speaker 1: ability to see them. Commets orbit in the Inner Solar System,

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Speaker 1: and so we can point our telescopes and we can

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Speaker 1: watch them, and we can see where they're going, and

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Speaker 1: we are not worried about them because we know where

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Speaker 1: basically all the big ones are. They reflect enough sunlight

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Speaker 1: for us to track them and predict their path for

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Speaker 1: a few hundred years. Once it astronomer gets like four

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Speaker 1: or five six measurements of the motion of an object,

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Speaker 1: they can pretty well predict its path. But comets have

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Speaker 1: very long periods. Some of these things have like hundreds

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Speaker 1: or thousands of years long period, which means the first

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Speaker 1: time we see it might be when it's headed towards

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Speaker 1: the Earth, which is why you might not get a

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Speaker 1: whole lot of warning. And they're going much much faster

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Speaker 1: because they're falling in from much further away. And those

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Speaker 1: of you who watch these guys might remember that this

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Speaker 1: happened in This is not just fiction. In comment entered

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Speaker 1: the Solar System and then smacked right into Jupiter. It

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Speaker 1: was spectacular. You could see it with your own telescope

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Speaker 1: in your own backyard, earth size fireballs rising from the

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Speaker 1: surface of Jupiter. It was like astronomical schadenfreud. You know,

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Speaker 1: it's pretty awesome, but we were glad it wasn't hitting us.

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Speaker 1: Those poor Jupidtonians Jupidonians having to have that name. Man,

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Speaker 1: we'll have to ask or hey, what he would prefer

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Speaker 1: as a name of that. It's definitely not jupiter Lyns.

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Speaker 1: That would be pretty awkward Jupeians. Maybe a much bit Cans,

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Speaker 1: my fellow Jupidicns. We can't necessarily know when a comment

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Speaker 1: is coming, but should we really be that worried? Our

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Speaker 1: atmosphere is pretty hot, so it seems like it could

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Speaker 1: melt a comment, right. Our atmosphere is pretty hot, and

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Speaker 1: you can melt a comment if it wasn't too big.

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Speaker 1: But remember the impactory that took out the dinosaurs million

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Speaker 1: years ago was only a few kilometers wide, So anything

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Speaker 1: bigger than that is going to make it to the

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Speaker 1: surface of the Earth and deposit a lot of kinetic energy.

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Speaker 1: And so that's why it's really important to think about

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Speaker 1: questions like, well, how big can a comment get? And

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Speaker 1: so today in the podcast will be asking that exact question,

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Speaker 1: how big can a comment get? Um Empire State building size?

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Speaker 1: That's that's my guest. You just like the mental visual

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Speaker 1: of the Empire state building crashing into the earth. Somebody's

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Speaker 1: got to do that in Hollywood. Maybe blue whale size,

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Speaker 1: because I also like the image of a blue whale

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Speaker 1: crashing in Earth. Man talk about a belly flop, right,

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Speaker 1: a blue whale coming from space and hitting the ocean. Ouch,

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Speaker 1: that sounds like it hurts well as usual. I was

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Speaker 1: curious what people out there in the Internet thought about

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Speaker 1: this question. Have people thought about how big a commt is?

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Speaker 1: Do they have any idea how large these snowballs from

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Speaker 1: the far reaches of space can be? So I asked

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Speaker 1: folks to volunteer to answer random physics questions to contribute

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Speaker 1: to the podcast. And if you would like to participate, lease,

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Speaker 1: don't be shy. You are very very welcome. No expertise

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Speaker 1: is required. Just email me two questions at Daniel and

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Speaker 1: Jorge dot com. So before you listen to these answers,

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Speaker 1: think to yourself, how big do you think a comet

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Speaker 1: can get here's what people had to say, pretty big.

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Speaker 1: But then it starts getting into like whether you classify

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Speaker 1: as common or a planet. I think comments can get

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Speaker 1: as big as some of the largest planets out there.

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Speaker 1: I think if something happens where planet gets out of

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Speaker 1: orbit or start pades away, um, then those planets could

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Speaker 1: then become free. Practically, I never thought that comments could

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Speaker 1: or like pigeonholed into a certain size. I think, you know,

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Speaker 1: it could just be a stray ice ball. But size

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Speaker 1: doesn't really matter for comments. Well, based purely on imagination,

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Speaker 1: I think comments can get as big as our moon.

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Speaker 1: I ventured to guess comments can become as large as

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Speaker 1: they can until they are too large to be called commets.

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Speaker 1: From what I know, commets are this frozen stuff of

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Speaker 1: dust and solids and gases. So it depends on what

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Speaker 1: the commet has in it, because most of the stuff

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Speaker 1: gets melted away as it enters and becomes warmer and hotter.

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Speaker 1: What would prevent a comment from getting too big? I

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Speaker 1: guess the two things that I can think of our

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Speaker 1: If it's too big, it could break up easily, and

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Speaker 1: hence you won't have one comment, you'll have multiple comments,

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Speaker 1: and that's related to the structure of it. The other

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Speaker 1: thing is that if you have something that's very big,

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Speaker 1: it's likely not made out of a large percentage of

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Speaker 1: ice crystals, is probably going to be highly metallic and

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Speaker 1: won't develop the tails of the comments. So that still

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Speaker 1: doesn't answer the question of how big can the comment get.

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Speaker 1: I would guess I don't know, three or four or

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Speaker 1: bus sizes. I don't know. I would imagine it will

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Speaker 1: get as big as it can without the dust squishing it,

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Speaker 1: because aren't commits quite low density. I suppose the gravity

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Speaker 1: might turn it into an asteroid. I'm not sure about

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Speaker 1: what the definitions are there, but I hope that's helped

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Speaker 1: in some way. That's a good question. I imagine they

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Speaker 1: could get bigger than an asteroid, depending on how much

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Speaker 1: gravity maybe they had when they were out far far

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Speaker 1: far in the far reaches of the solar systems or

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Speaker 1: the orc clouds, or wherever they get all their ice from. Like,

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Speaker 1: maybe they're just a particularly big chunk that gathered a

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Speaker 1: whole lot and solidified before it came rushing in towards

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Speaker 1: the center of our solar system. All right, so nobody

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Speaker 1: else that empire states building or whale sized. Well, I

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Speaker 1: am interested in the question of when does it become

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Speaker 1: a planet. Is the only thing separating something like a

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Speaker 1: comet and a planet just its signs? Or is there

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Speaker 1: some other property to a comet that makes it not

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Speaker 1: a planet? Oh man, this is such a tangle of names.

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Speaker 1: The astronomers have made such a mess of what they

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Speaker 1: call things. Is it a centaur, is it a trans

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Speaker 1: Newtonian object? It is a minor planet. There are such

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Speaker 1: ridiculous and sometimes conflicting rules about these things. In this case,

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Speaker 1: you can actually make a nice little line between what's

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Speaker 1: a comet and what's not. What you call a comet

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Speaker 1: is something that has an atmosphere because the Sun is

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Speaker 1: heating it up and it's out gassing. So imagine some

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Speaker 1: icy ball thousands of au away from the Sun. It's

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Speaker 1: just going to be sitting there frozen. But if it

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Speaker 1: falls in towards the Solar System and the Sun starts

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Speaker 1: to heat it up, then some of those ices are

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Speaker 1: going to turn into gas, and they're going to give

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Speaker 1: that comet a little atmosphere, which they call a co

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Speaker 1: and it might even give it a little tail if

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Speaker 1: some of it is blown off behind it. So that's

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Speaker 1: what distinguishes an asteroid from a comet or a planet,

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Speaker 1: or even a minor planet, or a or trans neptunity sorry,

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Speaker 1: trans Neptunian objects, not trans Newtonian. Nobody launched isamutany into

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Speaker 1: outer space yet they should have, though, that would teach

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Speaker 1: him a thing or two about gravity. So if these

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Speaker 1: comets have atmospheres, could this mean that some form of

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Speaker 1: life could conceivably breathe it in or is it just

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Speaker 1: inherently unfriendly towards life? Oh, I was hoping you were

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Speaker 1: going to go there, the biologist, and you can't resist

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Speaker 1: asking that question. Now, of course, we can never say never,

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Speaker 1: because life is weird and could take all sorts of

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Speaker 1: strange forms. But these would be very short lived atmospheres.

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Speaker 1: This is something that doesn't exist when it's out there,

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Speaker 1: deep into space. It only appears when the comet is

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Speaker 1: falling towards the Sun and it's not gravitationally bound like

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Speaker 1: these things are not big enough to have an atmosphere.

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Speaker 1: The reason an asteroid doesn't have an atmosphere is that

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Speaker 1: doesn't have enough gravity to hold onto it. Even the

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Speaker 1: Moon doesn't have enough gravity to hold onto it. If

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Speaker 1: you like pumped an atmosphere onto the moon. We all

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Speaker 1: just drift away in a few dozen years or maybe

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Speaker 1: a hundred. So a commet, it's atmosphere sort of transient.

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Speaker 1: It keeps losing it and then it keeps replenishing it

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Speaker 1: by outgassing it. So it'd be pretty hard situation, I

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Speaker 1: think for life to form. So you'd basically just get

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Speaker 1: a few puffs of atmosphere as life, but you wouldn't

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Speaker 1: have millions of years to evolve. On this comment more

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Speaker 1: of a vape situation. If you're a life form, Yeah,

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Speaker 1: unless you're something really weird form of life, which can

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Speaker 1: like go into stasis for a long long time and

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Speaker 1: then wake up again, like those insects that wake up

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Speaker 1: every seventeen years and like take a few breaths, live

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Speaker 1: a very short life as the common is diving towards

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Speaker 1: the sun, and then go back to sleep. Well, you know,

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Speaker 1: there is a life form already out in space that

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Speaker 1: can go into stays us and can survive the rigors

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Speaker 1: of the vacuum of space at least for short periods

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Speaker 1: of time, and those are tartar grades. So who knows,

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Speaker 1: maybe some of those tartar grades we accidentally dropped on

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Speaker 1: the moon, will someday find their way to sort of

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Speaker 1: ride a comet for a little while. You think maybe

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Speaker 1: they're gonna just like jump off the moon because there's

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Speaker 1: such a little gravity there, land on a comet and

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Speaker 1: ride it around the Solar system. That sounds pretty awesome,

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Speaker 1: like doctor Strange love Tartar Grade, little tiny silver surfers. Well,

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Speaker 1: that sounds like a great science fiction novel. So what

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00:17:40,040 --> 00:17:43,000
Speaker 1: we're talking about today are these comets, and these comments

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Speaker 1: are again distinguished from asteroids because they have a coma

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Speaker 1: and they can have a tail. A tail is not

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Speaker 1: actually necessary for it to be a comet. A lot

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Speaker 1: of people think about comments. They think about tails because

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Speaker 1: when you look up in the sky, that's how a

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Speaker 1: comet looks different from just like a star or something

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Speaker 1: else shiny. Technically, though, astronom will call it a comet

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Speaker 1: even if it doesn't yet have a tail, like before

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Speaker 1: it's really fallen into the inner Solar system, it can

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Speaker 1: still just have a coma. The other weird thing about

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Speaker 1: comets is that they don't always just have one tail.

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Speaker 1: They can have two different tails simultaneously, so just kind

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Speaker 1: of a split stream going on or these tails made

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Speaker 1: out of different stuff, so comments on that, like these

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Speaker 1: dirty snowballs, and some of the stuff when he gets

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Speaker 1: heated up, turns into gas and then the sun blows

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Speaker 1: that away. So one of the tails of a comet

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Speaker 1: is a gas tail, and that's pointing away from the sun.

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Speaker 1: A lot of people think like the comets tail is

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Speaker 1: pointing behind it, sort of like a rocket's exhaust or

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Speaker 1: like you know those wiggle motions in a cartoon. That

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Speaker 1: means that something is moving fast, but it's actually pointing

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Speaker 1: away from the sun, like the sun is blowing gas

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Speaker 1: away from it. So that's the gas tail. The other

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Speaker 1: tail is typically made out of dust to like little

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Speaker 1: bits of rock or whatever from the core of a comet,

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Speaker 1: the non ice parts, and those are a little heavier

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Speaker 1: so they don't get blown by the solar wind and

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Speaker 1: they do actually follow more like the trajectory of the comet.

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Speaker 1: So you have one tail that's sort of flying out

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Speaker 1: behind the comet along its path and the other one

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Speaker 1: that's getting blown away by the sun. And these are

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Speaker 1: not always pointed in the same direction. So if you're

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Speaker 1: really lucky, you can see a comet with both of

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Speaker 1: these tails. Simultaneously, it looks pretty spectacular. So for thinking

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Speaker 1: of a comet like a runway model, the gas tail

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Speaker 1: is its hair getting blown out of its face by

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Speaker 1: some conveniently placed fans, and the dust tail is like

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Speaker 1: it's cloak, kind of wafting behind it as it struts

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Speaker 1: down the runway, hopefully not towards Earth exactly. And if

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Speaker 1: you are running with a tail wind right when the

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Speaker 1: comet comes around the Sun and it's now going back

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Speaker 1: into the outer Solar System, then its tail is pointing

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Speaker 1: in the direction it's moving. It's like an anti tail

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Speaker 1: because the Sun is now behind it, and so it's

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Speaker 1: blowing gas in the direction the comet is moving. So

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Speaker 1: the tail isn't always even behind the comet. Sometimes it's

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Speaker 1: ahead of comment. So if we see a giant comet

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Speaker 1: that has a tail pointed in our direction, that does

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00:20:06,119 --> 00:20:08,719
Speaker 1: not mean we're not in danger, because it could be

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Speaker 1: coming right this way. That's right. You need me at

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Speaker 1: the white board or somebody else doing those calculations before

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Speaker 1: you know whether or not we should abandon the planet.

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Speaker 1: And these comments come into different groups. Some of them

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Speaker 1: are short period comets which come from the Piper Belt.

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Speaker 1: This is a region of just like icy stuff. Planetism

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Speaker 1: as just past Neptune, you know, past Neptune. This like

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Speaker 1: a whole, big, messy pile of stuff. That's why people

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Speaker 1: argue about whether Pluto should be a planet, because Pluto

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Speaker 1: is the first thing we saw out there that was

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Speaker 1: about that size, and then we discovered, oh my gosh,

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Speaker 1: there's a lot of these like frozen balls out there.

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Speaker 1: There are about Pluto size. We call Pluto a planet,

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Speaker 1: we've got to call them all planets. So like after Neptune,

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Speaker 1: the solar systems basically just a big mess. Sounds like

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Speaker 1: a lot of planetary gate keeping. Just because Pluto's a

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Speaker 1: mess doesn't mean it shouldn't be a planet. It's not

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Speaker 1: just that Pluto is a mess. It's Pluto, and it's

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Speaker 1: like seventeen thousand friends are all a mess, And do

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Speaker 1: you want a solar system with seventeen thousand planets in it?

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Speaker 1: You know, I guess it just depends on way to

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Speaker 1: think of a solar system. But you know, to me,

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Speaker 1: these arguments are just about names gues. It depends on

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Speaker 1: if they're bringing pizza money or if they're just coming

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00:21:14,160 --> 00:21:17,920
Speaker 1: there for the free food. That's right. Anybody who brings

385
00:21:17,960 --> 00:21:21,080
Speaker 1: gelato is welcome. But some of these little icy balls

386
00:21:21,160 --> 00:21:24,040
Speaker 1: out there and the Kuiper Belt can get nudged and

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00:21:24,160 --> 00:21:26,760
Speaker 1: fall into the Solar System. And these are called short

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Speaker 1: period comets, meaning that they take months or years to

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Speaker 1: go around the Solar System. But there's another group, these

390
00:21:33,080 --> 00:21:36,840
Speaker 1: long period comets that come from another source that much

391
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Speaker 1: further out passed even the Kuiper Belt way past Pluto,

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Speaker 1: many many, many thousands and millions of kilometers, and that

393
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Speaker 1: comes from this blob called the Oort Cloud, which is

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00:21:48,040 --> 00:21:51,760
Speaker 1: this theoretical cloud of icy many planets. And I say

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Speaker 1: theoretical because we're pretty sure it's there, but we've never

396
00:21:55,119 --> 00:21:59,360
Speaker 1: actually seen it, so we only know about it's possible

397
00:21:59,400 --> 00:22:04,080
Speaker 1: existence based on the garbage that it throws our way exactly.

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Speaker 1: We can't otherwise explain where these comments come from. And

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Speaker 1: so based on these comments about fifty years ago, Yon

400
00:22:11,600 --> 00:22:15,280
Speaker 1: Ord suggested maybe there's this huge group of icy balls

401
00:22:15,320 --> 00:22:18,160
Speaker 1: out there and just a tiny fraction them are occasionally

402
00:22:18,359 --> 00:22:21,280
Speaker 1: falling towards the Earth. So I want to talk a

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00:22:21,280 --> 00:22:23,680
Speaker 1: lot more about the Ord Cloud and what it contains

404
00:22:23,720 --> 00:22:26,520
Speaker 1: and the size of the comets that might be lurking

405
00:22:26,560 --> 00:22:42,199
Speaker 1: in there. But first, let's take a quick break. All right,

406
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Speaker 1: we're back and we're talking about what's going on in

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00:22:44,840 --> 00:22:48,880
Speaker 1: the messy outer reaches of the Solar system. Well passed Pluto,

408
00:22:49,240 --> 00:22:52,880
Speaker 1: well passed, all of the trans Neptunian objects, well passed

409
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Speaker 1: everything that might be called a planet, deep deep, deep

410
00:22:56,080 --> 00:23:00,000
Speaker 1: out there, more like a thousand or two thousand astronaut

411
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Speaker 1: coomical units past the Sun. There is this graveyard of

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Speaker 1: icy objects which might form future comments. So we only

413
00:23:08,720 --> 00:23:14,080
Speaker 1: know about this based on this sort of space junk

414
00:23:14,480 --> 00:23:19,399
Speaker 1: that comes our way. We've never actually seen the cloud

415
00:23:19,440 --> 00:23:23,879
Speaker 1: itself exactly, and that's because it's so far away. You know.

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Speaker 1: The an astronomical unit is the distance between the Sun

417
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Speaker 1: and the Earth, and the orc cloud starts like thousands

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00:23:30,600 --> 00:23:34,919
Speaker 1: of astronomical units, maybe up to fifty thousand astronomical units

419
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Speaker 1: from the Sun. We're talking like one to two light

420
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Speaker 1: years away. And it's really hard to see these objects

421
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Speaker 1: when they're so far away because they don't reflect a

422
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Speaker 1: whole lot of sun because not much sun gets there,

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Speaker 1: and they're so small that not much of their light

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00:23:49,280 --> 00:23:51,520
Speaker 1: comes back to us. You know, they're not glowing on

425
00:23:51,600 --> 00:23:54,320
Speaker 1: their own like stars. We can only see them if

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00:23:54,320 --> 00:23:56,960
Speaker 1: the light reflects it just the right angle and there's

427
00:23:57,119 --> 00:24:00,240
Speaker 1: enough of it. So we've never seen it directly. We've

428
00:24:00,280 --> 00:24:02,760
Speaker 1: only seen the ones that are falling towards the earth,

429
00:24:03,080 --> 00:24:05,960
Speaker 1: and from that we're trying to guess what's out there.

430
00:24:06,400 --> 00:24:08,480
Speaker 1: It's like if you couldn't see clouds, but you could

431
00:24:08,480 --> 00:24:11,119
Speaker 1: measure rain, and you're wondering, like, what's up there in

432
00:24:11,160 --> 00:24:14,439
Speaker 1: the sky. Maybe there are these huge reservoirs of water

433
00:24:14,520 --> 00:24:17,080
Speaker 1: floating above us. Or it's like when you can't see

434
00:24:17,119 --> 00:24:19,359
Speaker 1: a squirrel in a tree, but you know it must

435
00:24:19,359 --> 00:24:22,000
Speaker 1: be there because you keep getting little pieces of acorn

436
00:24:22,040 --> 00:24:25,800
Speaker 1: shell showering down on your head. Yeah, exactly. And the

437
00:24:26,080 --> 00:24:29,440
Speaker 1: range of speculation for like how much stuff is out

438
00:24:29,480 --> 00:24:32,719
Speaker 1: there is enormous. It could be that there are billions

439
00:24:32,720 --> 00:24:34,840
Speaker 1: of icy objects out there. It could be that there

440
00:24:34,880 --> 00:24:38,719
Speaker 1: are trillions of icy objects out there. It all depends

441
00:24:38,720 --> 00:24:41,280
Speaker 1: on also, like how big they are, Like there could

442
00:24:41,320 --> 00:24:44,359
Speaker 1: be billions of things like twenty kilometers wide or larger,

443
00:24:44,400 --> 00:24:46,439
Speaker 1: but if you get too smaller and smaller objects like

444
00:24:46,560 --> 00:24:50,440
Speaker 1: just kilometer or so, there could be even trillions out there.

445
00:24:50,560 --> 00:24:53,040
Speaker 1: And it's a lot of stuff that we're talking about.

446
00:24:53,359 --> 00:24:55,760
Speaker 1: They speculate that if you add up all of this stuff,

447
00:24:55,800 --> 00:24:59,280
Speaker 1: it's like five to ten times the mass of the Earth.

448
00:24:59,720 --> 00:25:02,800
Speaker 1: So it's not a small amount of basic material that's

449
00:25:02,920 --> 00:25:06,080
Speaker 1: orbiting out there in the distance waiting for its trip

450
00:25:06,119 --> 00:25:10,000
Speaker 1: around the Sun. So how much can we determine just

451
00:25:10,160 --> 00:25:15,160
Speaker 1: based on the sort of fall off that happens from

452
00:25:15,200 --> 00:25:18,040
Speaker 1: this proposed or cloud, like do we know the shape

453
00:25:18,040 --> 00:25:21,240
Speaker 1: of it or can we just kind of basically guess, well,

454
00:25:21,280 --> 00:25:23,439
Speaker 1: it's there and maybe it's big. A lot of it

455
00:25:23,480 --> 00:25:25,800
Speaker 1: is guesswork based on modeling. We try to think about

456
00:25:25,840 --> 00:25:28,800
Speaker 1: how the Solar system formed, how stuff would end up,

457
00:25:28,840 --> 00:25:31,600
Speaker 1: what's likely to be out there, and that really informs

458
00:25:31,640 --> 00:25:34,399
Speaker 1: a lot of our understanding of the Solar system for

459
00:25:34,480 --> 00:25:37,159
Speaker 1: things that we cannot see. And that doesn't mean that

460
00:25:37,200 --> 00:25:39,439
Speaker 1: it's bolognay, it's not just something we're making up. You know,

461
00:25:39,480 --> 00:25:42,200
Speaker 1: this is a really valuable part of how we do sciences.

462
00:25:42,320 --> 00:25:45,879
Speaker 1: We try to tell a complete holistic story of the

463
00:25:45,920 --> 00:25:48,080
Speaker 1: Solar system and say, if this is true and that

464
00:25:48,200 --> 00:25:50,560
Speaker 1: is true, what does that mean about the early times

465
00:25:50,680 --> 00:25:53,160
Speaker 1: or the late times or what's going on. It's really

466
00:25:53,240 --> 00:25:55,399
Speaker 1: valuable and you know, you can take the measurements that

467
00:25:55,440 --> 00:25:57,320
Speaker 1: we have and you try to make them consistent with

468
00:25:57,359 --> 00:25:59,960
Speaker 1: that story. And so they think about this huge cloud

469
00:26:00,000 --> 00:26:02,760
Speaker 1: out of gas and dust and ice crystals that helped

470
00:26:02,840 --> 00:26:05,400
Speaker 1: form the Solar System. The reason we talk about ice

471
00:26:05,440 --> 00:26:07,720
Speaker 1: in the far reaches of the Solar System is because

472
00:26:07,720 --> 00:26:10,320
Speaker 1: it's cold out there and ice melts, and any water

473
00:26:10,400 --> 00:26:13,200
Speaker 1: that was closer before the snow line they call it

474
00:26:13,240 --> 00:26:16,160
Speaker 1: would have been liquid or vapor, and so it wouldn't

475
00:26:16,200 --> 00:26:19,920
Speaker 1: form these icy objects. So we think, based on these models,

476
00:26:19,960 --> 00:26:22,840
Speaker 1: that the Orc Cloud has sort of two different shapes.

477
00:26:22,920 --> 00:26:24,960
Speaker 1: That's like an inner or cloud that's sort of like

478
00:26:25,000 --> 00:26:27,439
Speaker 1: a doughnut sort of flat, like the rest of the

479
00:26:27,440 --> 00:26:29,720
Speaker 1: Solar System. And this might be from like a few

480
00:26:29,880 --> 00:26:32,760
Speaker 1: thousand a U out to like twenty thousand a U.

481
00:26:33,400 --> 00:26:36,119
Speaker 1: And then there might be like a larger spherical or

482
00:26:36,240 --> 00:26:39,439
Speaker 1: cloud surrounding the entire Solar System, like a huge ball

483
00:26:39,800 --> 00:26:42,800
Speaker 1: that goes out to like fifty thousand a U or

484
00:26:42,840 --> 00:26:46,280
Speaker 1: even further. And that's sort of like at the edge

485
00:26:46,359 --> 00:26:49,280
Speaker 1: of the interstellar distance. You know, other stars are like

486
00:26:49,320 --> 00:26:52,040
Speaker 1: a few light years away. So now we're talking about

487
00:26:52,080 --> 00:26:54,879
Speaker 1: like the very edges of our little corner of space

488
00:26:55,000 --> 00:26:59,119
Speaker 1: bumping up against other stars, edges of their space, and

489
00:26:59,240 --> 00:27:03,400
Speaker 1: so may be this sort cloud and these big icy

490
00:27:03,520 --> 00:27:07,800
Speaker 1: for us to donuts can only exist between solar systems

491
00:27:07,840 --> 00:27:10,679
Speaker 1: because otherwise they get too warm or they get pulled

492
00:27:10,680 --> 00:27:13,680
Speaker 1: in and then become a comet that eventually melts or

493
00:27:13,760 --> 00:27:17,000
Speaker 1: collides with something. Exactly in order to be an ice blob,

494
00:27:17,080 --> 00:27:19,239
Speaker 1: you have to be far away from the star, and

495
00:27:19,240 --> 00:27:21,400
Speaker 1: that's why Earth, for example, is not an ice ball.

496
00:27:21,480 --> 00:27:23,960
Speaker 1: It's just too warm and mercury and venus, and that's

497
00:27:24,000 --> 00:27:26,680
Speaker 1: why the icy planets are far away from the Sun.

498
00:27:27,080 --> 00:27:29,240
Speaker 1: And as you say, these things are too far away

499
00:27:29,280 --> 00:27:30,880
Speaker 1: to get melted. So that's where you go to find

500
00:27:30,880 --> 00:27:34,360
Speaker 1: gelato on your trip between stars. I'm glad I don't

501
00:27:34,359 --> 00:27:37,680
Speaker 1: have to walk as far here for gelato, but it

502
00:27:37,680 --> 00:27:40,240
Speaker 1: would still be worth it. Right, Gelato is just that good.

503
00:27:40,480 --> 00:27:42,520
Speaker 1: But it's really fascinating to me because it shows you

504
00:27:42,600 --> 00:27:45,159
Speaker 1: something of the tug of war between solar systems. We

505
00:27:45,280 --> 00:27:47,919
Speaker 1: tend to think of stars as like totally separate. We

506
00:27:47,960 --> 00:27:50,760
Speaker 1: have our solar system, they got their solar system, and

507
00:27:50,800 --> 00:27:53,680
Speaker 1: maybe very rarely two stars will come near each other

508
00:27:53,720 --> 00:27:56,520
Speaker 1: and there'll be chaos. But in reality, there's like a

509
00:27:56,600 --> 00:28:00,520
Speaker 1: constant tug of war at the boundaries between the Solar system.

510
00:28:00,560 --> 00:28:03,800
Speaker 1: Like imagine you're halfway between two stars and you're feeling

511
00:28:04,200 --> 00:28:07,800
Speaker 1: gentle gravity from both stars, and so you're being tugged

512
00:28:07,800 --> 00:28:10,600
Speaker 1: one way, tugged another way, And that's these stars are

513
00:28:10,640 --> 00:28:13,600
Speaker 1: moving relative to each other, that gravity is changing. So

514
00:28:13,640 --> 00:28:16,879
Speaker 1: maybe you get like bumped from one solar system to another,

515
00:28:17,240 --> 00:28:20,560
Speaker 1: which means that, like some parts of our Worth Cloud

516
00:28:21,000 --> 00:28:23,639
Speaker 1: might not be from our Solar system. They might have

517
00:28:23,720 --> 00:28:26,480
Speaker 1: like started out in another solar system and then got

518
00:28:26,520 --> 00:28:30,120
Speaker 1: past two hours, maybe several times. Maybe they're like hopscotching

519
00:28:30,200 --> 00:28:32,760
Speaker 1: from solar system to solar system. Could that be one

520
00:28:32,840 --> 00:28:36,080
Speaker 1: reason that our solar system is able to host our

521
00:28:36,160 --> 00:28:39,920
Speaker 1: comfy little planet Earth without having gotten pummeled by too

522
00:28:39,920 --> 00:28:43,480
Speaker 1: many comments? Could there be a benevolent Solar system out

523
00:28:43,480 --> 00:28:48,080
Speaker 1: there absorbing or sucking in more comments. I like your

524
00:28:48,080 --> 00:28:50,600
Speaker 1: optimistic theory of the universe that there's somebody out there

525
00:28:50,680 --> 00:28:53,560
Speaker 1: looking out for us by eating all the gelato before

526
00:28:53,560 --> 00:28:56,480
Speaker 1: it falls to Earth to kill us. It could be yeah,

527
00:28:56,520 --> 00:29:00,280
Speaker 1: you know, maybe not intentionally, but just by here a

528
00:29:00,400 --> 00:29:04,360
Speaker 1: chance a son out, they're kind of preventing more of

529
00:29:04,400 --> 00:29:08,720
Speaker 1: these frozen ice balls from colliding with our Solar System,

530
00:29:08,760 --> 00:29:11,040
Speaker 1: it could be, or it could be even closer to home.

531
00:29:11,120 --> 00:29:14,200
Speaker 1: A lot of folks think that our gas giants Saturn

532
00:29:14,200 --> 00:29:18,760
Speaker 1: and Jupiter provides something of a gravitational shield against impactors

533
00:29:18,760 --> 00:29:20,880
Speaker 1: in the inner Solar System, and that like a lot

534
00:29:20,920 --> 00:29:23,000
Speaker 1: of the icy balls in the or cloud are there

535
00:29:23,040 --> 00:29:25,800
Speaker 1: because they got thrown out of the Solar System early

536
00:29:25,880 --> 00:29:28,760
Speaker 1: on by these gas giants as things were like still

537
00:29:28,800 --> 00:29:32,600
Speaker 1: coming together, and so now they're like lurking outside waiting

538
00:29:32,640 --> 00:29:34,680
Speaker 1: for their chance to come back into the light. Well,

539
00:29:34,720 --> 00:29:38,560
Speaker 1: it seems like for some planets that maybe protecting all

540
00:29:38,640 --> 00:29:40,520
Speaker 1: life on Earth, we should come up with a more

541
00:29:40,600 --> 00:29:45,040
Speaker 1: flattering name than gas giants. But you know, I guess

542
00:29:45,080 --> 00:29:48,000
Speaker 1: that's it's accurate at least. Well, you know, we did

543
00:29:48,120 --> 00:29:50,360
Speaker 1: name them after the most important gods, you know, like

544
00:29:50,480 --> 00:29:53,840
Speaker 1: Jupiter and Zeus, so that you know, that's pretty flattering. Right,

545
00:29:54,040 --> 00:29:57,240
Speaker 1: there's no planet named Zeus. Zeus is the Greek version

546
00:29:57,280 --> 00:29:59,720
Speaker 1: of Jupiter, isn't it right? Yes, that's right, that's right.

547
00:29:59,840 --> 00:30:01,760
Speaker 1: I think z would be a much better name for

548
00:30:01,800 --> 00:30:04,240
Speaker 1: a planet than Jupiter. Right, I'm petitioning that we renamed

549
00:30:04,280 --> 00:30:06,720
Speaker 1: Jupiter Zeus because then the people who live on it

550
00:30:06,760 --> 00:30:09,840
Speaker 1: would be called Zeusians. That rolls off the tongue much nicer,

551
00:30:09,960 --> 00:30:12,840
Speaker 1: and then you can't have that schoolyard chant of girls

552
00:30:12,880 --> 00:30:15,560
Speaker 1: go to Jupiter to get more stupider. So I'm all

553
00:30:15,600 --> 00:30:19,840
Speaker 1: for it. Heard that one that's terrible. Well, it goes

554
00:30:19,880 --> 00:30:22,440
Speaker 1: either way. You can say boys go to Jupiter to

555
00:30:22,480 --> 00:30:25,560
Speaker 1: get more stupider, girls go to Mars to drive cool cars,

556
00:30:25,680 --> 00:30:28,160
Speaker 1: or vice versa. But you know, I think we should

557
00:30:28,240 --> 00:30:32,640
Speaker 1: be breaking those rigid gender roles in terms of planets.

558
00:30:32,840 --> 00:30:35,800
Speaker 1: Totally agree. And so one question about what's out there

559
00:30:35,800 --> 00:30:37,720
Speaker 1: in the or cloud is just like how did it

560
00:30:37,800 --> 00:30:40,960
Speaker 1: get formed and what's its composition? But a big and

561
00:30:41,000 --> 00:30:43,840
Speaker 1: important question, and one that might really affect our future

562
00:30:44,280 --> 00:30:47,000
Speaker 1: is how big are the things out there? You know,

563
00:30:47,040 --> 00:30:49,000
Speaker 1: a lot of the comets that we have seen coming

564
00:30:49,080 --> 00:30:51,880
Speaker 1: in our Solar System are just a few kilometers wide,

565
00:30:51,880 --> 00:30:54,600
Speaker 1: and they're big enough to be spectacular. But people wonder, like,

566
00:30:55,040 --> 00:30:58,440
Speaker 1: are their planet sized objects out there in the or cloud?

567
00:30:58,480 --> 00:31:01,560
Speaker 1: Could one of them fall into the inner Solar System

568
00:31:01,880 --> 00:31:04,840
Speaker 1: and like really do some damage. So if there's an

569
00:31:04,880 --> 00:31:08,560
Speaker 1: ice ball hang out there that is planet sized, would

570
00:31:08,600 --> 00:31:12,480
Speaker 1: it be considered a planet before it becomes a comet?

571
00:31:12,640 --> 00:31:15,360
Speaker 1: Or is it just considered some kind of ice ball.

572
00:31:15,520 --> 00:31:18,040
Speaker 1: I think that the new definition of planet makes it

573
00:31:18,080 --> 00:31:21,600
Speaker 1: basically impossible because an object has to like clear its

574
00:31:21,600 --> 00:31:24,520
Speaker 1: own path, that has to basically have its own unique

575
00:31:24,520 --> 00:31:26,640
Speaker 1: path through the Solar System to be called a planet.

576
00:31:26,800 --> 00:31:29,560
Speaker 1: But I also think that there are now conflicting definitions

577
00:31:29,560 --> 00:31:31,719
Speaker 1: of what a planet is. But as soon as it

578
00:31:31,760 --> 00:31:34,840
Speaker 1: falls in towards the Solar System and develops a coma,

579
00:31:35,320 --> 00:31:37,440
Speaker 1: then it's a comet, even if it used to be

580
00:31:37,520 --> 00:31:40,840
Speaker 1: like the Moon sized or Pluto sized, or even I

581
00:31:40,840 --> 00:31:43,680
Speaker 1: guess Neptune sized, right, Like one of the listeners was

582
00:31:43,720 --> 00:31:46,720
Speaker 1: guessing planets that lose their orbits could be comets, Like

583
00:31:46,920 --> 00:31:49,479
Speaker 1: that's really crazy to think about. They would be at

584
00:31:49,560 --> 00:31:54,320
Speaker 1: least ice planets. So could there be a big ice

585
00:31:54,400 --> 00:31:57,840
Speaker 1: ball the size of Earth that at some point comes

586
00:31:57,840 --> 00:32:01,000
Speaker 1: in and smashes into our Solar System? Like? How much

587
00:32:01,000 --> 00:32:04,280
Speaker 1: sleep should I lose after otarting this podcast? Well, we

588
00:32:04,400 --> 00:32:06,840
Speaker 1: just don't know, is the thing. It's a mystery to us.

589
00:32:06,960 --> 00:32:09,360
Speaker 1: One thing we do know is that most of the

590
00:32:09,360 --> 00:32:12,000
Speaker 1: things that fall in from the or cloud tend to

591
00:32:12,000 --> 00:32:14,720
Speaker 1: be smaller. But there's now a spectrum and we're seeing

592
00:32:14,800 --> 00:32:17,640
Speaker 1: larger and larger objects. So the thing that should scare

593
00:32:17,680 --> 00:32:20,920
Speaker 1: you is that as we keep studying, we keep discovering

594
00:32:21,040 --> 00:32:23,480
Speaker 1: larger and larger objects of the Orc cloud. We'll talk

595
00:32:23,480 --> 00:32:26,600
Speaker 1: about one particular monster in a minute. So that should

596
00:32:26,680 --> 00:32:29,200
Speaker 1: terrify you because it might mean that there are really

597
00:32:29,320 --> 00:32:32,080
Speaker 1: some huge blobs of ice waiting out there. The thing

598
00:32:32,120 --> 00:32:34,480
Speaker 1: that should help you fall asleep, though, is that we

599
00:32:34,560 --> 00:32:37,520
Speaker 1: do know that there's an inverse relationship between how many

600
00:32:37,640 --> 00:32:40,800
Speaker 1: there are and their size. Like with everything else, there's

601
00:32:40,920 --> 00:32:42,880
Speaker 1: going to be lots and lots of dust screens, and

602
00:32:42,880 --> 00:32:45,240
Speaker 1: then it's wund be fewer things the size of snowball,

603
00:32:45,280 --> 00:32:48,640
Speaker 1: and fewer things the size of a bus, and even

604
00:32:48,720 --> 00:32:51,120
Speaker 1: fewer things the size of you know, there are ten

605
00:32:51,200 --> 00:32:54,000
Speaker 1: kilometers across. The interesting thing is we don't know what

606
00:32:54,040 --> 00:32:56,760
Speaker 1: the maximum is like. There might just be one real

607
00:32:56,840 --> 00:33:00,000
Speaker 1: monster out there. But how big is the biggest monster?

608
00:33:00,280 --> 00:33:02,959
Speaker 1: If you can't see it, if we're too far away

609
00:33:03,000 --> 00:33:04,960
Speaker 1: to be able to see it with any of our

610
00:33:05,160 --> 00:33:07,960
Speaker 1: monitoring tools from here on Earth or even you know,

611
00:33:07,960 --> 00:33:10,000
Speaker 1: the ones that we send out on the edges of

612
00:33:10,000 --> 00:33:13,600
Speaker 1: our solar system, how would you be able to guess

613
00:33:14,160 --> 00:33:17,240
Speaker 1: the size of the biggest ice ball. Yeah, you would

614
00:33:17,280 --> 00:33:19,280
Speaker 1: have to use some models. You'd have to understand how

615
00:33:19,360 --> 00:33:21,600
Speaker 1: all those ice balls formed. Then you'd have to develop

616
00:33:21,600 --> 00:33:25,080
Speaker 1: a simulation that ran through the formation of the Solar system,

617
00:33:25,280 --> 00:33:27,920
Speaker 1: and you'd look for models that explain what we do see.

618
00:33:28,240 --> 00:33:30,800
Speaker 1: You know that look at this relationship between size and

619
00:33:30,920 --> 00:33:34,480
Speaker 1: frequency and correctly predict that, and then you can extrapolate.

620
00:33:34,480 --> 00:33:36,600
Speaker 1: You could say, well, as they get bigger, if the

621
00:33:36,720 --> 00:33:39,640
Speaker 1: rate of their occurrence drops by you know, some factor,

622
00:33:39,920 --> 00:33:42,280
Speaker 1: then you could follow that line forward and try to

623
00:33:42,320 --> 00:33:46,200
Speaker 1: predict like how big theoretically an object could be. But

624
00:33:46,240 --> 00:33:47,520
Speaker 1: this is the kind of thing that we do all

625
00:33:47,560 --> 00:33:50,440
Speaker 1: the time in astronomy, and then we're surprised, Like we

626
00:33:50,520 --> 00:33:54,280
Speaker 1: have predictions for how big the largest galactic clusters should be,

627
00:33:54,480 --> 00:33:56,800
Speaker 1: and then we keep finding bigger ones. Were like, well,

628
00:33:56,880 --> 00:33:59,240
Speaker 1: I guess something was wrong, but that's just the process

629
00:33:59,240 --> 00:34:02,560
Speaker 1: of science. And so until we actually see these things,

630
00:34:02,600 --> 00:34:05,680
Speaker 1: were often not sure about what the upper limits are.

631
00:34:06,000 --> 00:34:09,799
Speaker 1: So we would have to base it on the sort

632
00:34:09,800 --> 00:34:12,839
Speaker 1: of our existing models and things we can observe and

633
00:34:13,000 --> 00:34:16,640
Speaker 1: sort of use that to extrapolate what it is. But

634
00:34:17,200 --> 00:34:20,400
Speaker 1: do we know theoretically if there is a limit to

635
00:34:20,640 --> 00:34:25,080
Speaker 1: just physically to an ice ball. How big can an

636
00:34:25,120 --> 00:34:28,400
Speaker 1: object made with a solid core and then sort of

637
00:34:28,440 --> 00:34:31,359
Speaker 1: an icy exterior get that we know of. I think

638
00:34:31,400 --> 00:34:34,000
Speaker 1: there are some theoretical limits you good place, Like we

639
00:34:34,080 --> 00:34:36,239
Speaker 1: know that you could be as big as Neptune or

640
00:34:36,360 --> 00:34:38,719
Speaker 1: Uranus because we see those and those are basically the

641
00:34:38,760 --> 00:34:41,400
Speaker 1: same thing. A huge balls of ice with a rocky core.

642
00:34:41,560 --> 00:34:44,799
Speaker 1: If it gets much bigger than that Jupiter size, that

643
00:34:44,840 --> 00:34:47,759
Speaker 1: could still exist. If it gets even bigger than that,

644
00:34:47,800 --> 00:34:50,120
Speaker 1: if it gets like a hundred times to size of Jubiter,

645
00:34:50,440 --> 00:34:52,920
Speaker 1: then it would be big enough to ignite fusion in

646
00:34:53,000 --> 00:34:55,399
Speaker 1: its core and it would start to glow. We would

647
00:34:55,480 --> 00:34:58,480
Speaker 1: definitely see that. If there was another star out there

648
00:34:58,480 --> 00:35:01,080
Speaker 1: that was actually emitting light, we would see it. So

649
00:35:01,120 --> 00:35:03,680
Speaker 1: the orc cloud is dark, and that in itself puts

650
00:35:03,719 --> 00:35:06,480
Speaker 1: a limit on the biggest thing that could be in there.

651
00:35:06,560 --> 00:35:09,240
Speaker 1: You can't have a glowing star in the word cloud.

652
00:35:09,280 --> 00:35:12,719
Speaker 1: So like a hundred jupiters is the biggest anything could

653
00:35:12,760 --> 00:35:17,480
Speaker 1: be theoretically, But that's really big, like Jupiter itself is

654
00:35:17,520 --> 00:35:20,799
Speaker 1: three hundred times the mass of the Earth. So that's

655
00:35:20,800 --> 00:35:25,400
Speaker 1: not a very useful limit. It doesn't really reassure anybody.

656
00:35:25,800 --> 00:35:28,680
Speaker 1: We wouldn't be less dead if we were hit by

657
00:35:29,520 --> 00:35:33,040
Speaker 1: a half the size of Jupiter, Comment versus twice the

658
00:35:33,080 --> 00:35:36,560
Speaker 1: size of Jupiter. Comment would be equally dead in both scenarios,

659
00:35:36,640 --> 00:35:39,200
Speaker 1: is what you're saying? Yeah, exactly, though the astronomers would

660
00:35:39,239 --> 00:35:42,399
Speaker 1: be like, oh wow, that's really interesting. We're surprised just

661
00:35:42,520 --> 00:35:45,160
Speaker 1: before we all get blown up. Hey, well that's worth something.

662
00:35:46,480 --> 00:35:48,600
Speaker 1: At least the astronomers will get their kicks as we're

663
00:35:48,680 --> 00:35:52,280
Speaker 1: munch agone gelato. But recently we did spot a pretty

664
00:35:52,400 --> 00:35:55,799
Speaker 1: big monster object in the Orc Cloud heading towards the

665
00:35:55,800 --> 00:35:58,960
Speaker 1: Inner Solar System. That kind of surprised astronomers. Nobody had

666
00:35:59,000 --> 00:36:02,280
Speaker 1: ever seen some this large, and it sort of stretched

667
00:36:02,280 --> 00:36:05,120
Speaker 1: people's brains about how big one of these I see

668
00:36:05,160 --> 00:36:08,520
Speaker 1: objects could be. It's not Jupiter size, but it is

669
00:36:08,600 --> 00:36:11,640
Speaker 1: pretty large. So the object that hit the Earth sixty

670
00:36:11,680 --> 00:36:15,600
Speaker 1: five billion years ago was about five to six kilometers wide.

671
00:36:15,800 --> 00:36:18,600
Speaker 1: We think based on reconstructions, how much is that in

672
00:36:18,640 --> 00:36:22,880
Speaker 1: blue whales? That's not a physical unit I'm familiar with,

673
00:36:23,040 --> 00:36:26,760
Speaker 1: so I have to type that into Google. Wealth blue

674
00:36:26,760 --> 00:36:30,480
Speaker 1: whale is maybe about thirty long yea, So we're talking

675
00:36:30,520 --> 00:36:34,000
Speaker 1: about something that's two hundred blue whales long by volume,

676
00:36:34,080 --> 00:36:36,960
Speaker 1: that would make it like eight million blue whales. That's

677
00:36:37,000 --> 00:36:40,520
Speaker 1: a lot of blue whales, exactly eight million blue whales

678
00:36:40,760 --> 00:36:44,160
Speaker 1: rolled into a six kilometer wide ball impacting the Earth

679
00:36:44,320 --> 00:36:46,799
Speaker 1: would not be a great situation. But that's basically what

680
00:36:46,920 --> 00:36:50,760
Speaker 1: happened sixty five million years ago. But two astronomers called

681
00:36:50,840 --> 00:36:54,200
Speaker 1: Bernadelli and Bernstein recently spotted an object that they think

682
00:36:54,360 --> 00:36:58,160
Speaker 1: is a hundred to two hundred kilometers across, so like

683
00:36:58,840 --> 00:37:01,319
Speaker 1: much bigger and the one that hit the Earth and

684
00:37:01,400 --> 00:37:05,200
Speaker 1: caused an environmental cataclysm that changed the future of the planet.

685
00:37:05,239 --> 00:37:08,320
Speaker 1: This thing is forty times bigger, so we'll lose forty

686
00:37:08,360 --> 00:37:13,120
Speaker 1: times the number of dinosaurs this time around. You don't

687
00:37:13,200 --> 00:37:17,520
Speaker 1: think its scales that way. Don't tell me how to

688
00:37:17,560 --> 00:37:20,960
Speaker 1: do a math. That's a hefty that's a hefty comment.

689
00:37:21,120 --> 00:37:25,080
Speaker 1: How far away is it? Just asking for general, generally interested.

690
00:37:26,000 --> 00:37:30,160
Speaker 1: This thing we think started its journey around forty thousand

691
00:37:30,360 --> 00:37:33,160
Speaker 1: a US away, so deep deep in the Orc cloud.

692
00:37:33,440 --> 00:37:36,080
Speaker 1: And last time it was spotted middle of last year,

693
00:37:36,120 --> 00:37:39,320
Speaker 1: it was about twenty a U away, So that's twenty

694
00:37:39,400 --> 00:37:41,520
Speaker 1: times the distance from the Sun to the Earth, so

695
00:37:41,520 --> 00:37:44,560
Speaker 1: still really really far away, and so I want to

696
00:37:44,600 --> 00:37:47,320
Speaker 1: talk about how we spotted this thing, what its future

697
00:37:47,360 --> 00:37:50,520
Speaker 1: trajectory is, what we might learn about the deep reaches

698
00:37:50,560 --> 00:37:53,680
Speaker 1: of the Solar System by studying this massive comment. But first,

699
00:37:53,800 --> 00:37:56,120
Speaker 1: let's take another quick break and I'm going to take

700
00:37:56,160 --> 00:38:11,239
Speaker 1: some deep breathing. All right, we're back, and we're talking

701
00:38:11,239 --> 00:38:14,200
Speaker 1: about a ginormous visitor from the far edges of the

702
00:38:14,200 --> 00:38:18,360
Speaker 1: Solar system. Comment Bernadeli Bernstein. And I don't know anything

703
00:38:18,360 --> 00:38:22,040
Speaker 1: about Bernardelli or Bernstein, but I'm imagining this very nice

704
00:38:22,080 --> 00:38:24,919
Speaker 1: friendship between an Italian guy and the Jewish guy having

705
00:38:24,920 --> 00:38:29,000
Speaker 1: an ice cream, having a gelato, discovering a giant comment. Yeah,

706
00:38:29,040 --> 00:38:31,520
Speaker 1: maybe they're having some gelato on their bobka, you know,

707
00:38:31,560 --> 00:38:35,440
Speaker 1: and they're just like really fusing the cultures together. Yeah,

708
00:38:35,600 --> 00:38:40,279
Speaker 1: having some halva and some here you go. You know,

709
00:38:40,320 --> 00:38:43,279
Speaker 1: every culture has its take on ice cream. But now,

710
00:38:43,320 --> 00:38:45,120
Speaker 1: for the life of me, I can't think what is

711
00:38:45,160 --> 00:38:47,000
Speaker 1: the Jewish version of ice cream? Do we have our

712
00:38:47,040 --> 00:38:48,839
Speaker 1: own kind of ice cream? I don't know. That's why

713
00:38:48,880 --> 00:38:52,720
Speaker 1: I said halva, because that's sort of the creamiest dessert

714
00:38:52,760 --> 00:38:55,520
Speaker 1: I know of. But yeah, I'm I am not sure.

715
00:38:56,040 --> 00:39:01,480
Speaker 1: Desert cultures, I guess don't have an everything exactly except

716
00:39:01,520 --> 00:39:04,520
Speaker 1: for those of us who ended up in Siberia. Yeah, yeah, right,

717
00:39:04,640 --> 00:39:07,279
Speaker 1: So we are importing gelato from the far regions of

718
00:39:07,280 --> 00:39:10,280
Speaker 1: the Solar System into our desert culture. Here as comment

719
00:39:10,400 --> 00:39:14,839
Speaker 1: Bernard Deli Bernstein comes closer to the Sun, is developing

720
00:39:14,880 --> 00:39:17,399
Speaker 1: a coma. So that's why we don't call this thing

721
00:39:17,480 --> 00:39:20,920
Speaker 1: a minor planet or a dwarf Planet's officially a comet

722
00:39:20,960 --> 00:39:23,239
Speaker 1: because it's grown a coma. They can see this thing

723
00:39:23,520 --> 00:39:26,440
Speaker 1: out gassing and it's like surrounded by this little puff

724
00:39:26,520 --> 00:39:30,799
Speaker 1: of gas. So again, just generally interested, no big deal.

725
00:39:30,880 --> 00:39:33,799
Speaker 1: But do we know the direction this giant comment is

726
00:39:33,840 --> 00:39:36,360
Speaker 1: going in? We do. We've spotted it a few times,

727
00:39:36,360 --> 00:39:38,200
Speaker 1: We've made a bunch of measurements, and so we can

728
00:39:38,360 --> 00:39:41,839
Speaker 1: predict its trajectory. It looks like the closest it's gonna

729
00:39:41,920 --> 00:39:45,600
Speaker 1: come is in twenty thirty one. It's gonna come within

730
00:39:45,680 --> 00:39:49,319
Speaker 1: around eleven A U. So that's the closest to the

731
00:39:49,320 --> 00:39:52,399
Speaker 1: Sun it's gonna get, which means we are totally safe. Right,

732
00:39:52,440 --> 00:39:54,800
Speaker 1: We are at one a U. So this thing is

733
00:39:54,840 --> 00:39:57,279
Speaker 1: going to be really far away compared to us, and

734
00:39:57,320 --> 00:40:00,160
Speaker 1: so this comment is going to swoop actually up it's

735
00:40:00,200 --> 00:40:03,760
Speaker 1: like not following the plane of the ecliptic. It's actually

736
00:40:03,840 --> 00:40:06,840
Speaker 1: coming like sort of from below the plane. It's going

737
00:40:06,920 --> 00:40:10,240
Speaker 1: to swoop up between the orbits of Saturn and Uranus,

738
00:40:10,520 --> 00:40:13,319
Speaker 1: and then it's going to pass above the Solar System.

739
00:40:13,360 --> 00:40:16,239
Speaker 1: So these commets aren't necessarily limited to the plane of

740
00:40:16,280 --> 00:40:19,200
Speaker 1: the Solar System because they come from this spherical cloud

741
00:40:19,280 --> 00:40:22,680
Speaker 1: of objects the outer word cloud. So it probably had

742
00:40:22,719 --> 00:40:27,719
Speaker 1: its own trajectory and velocity before it started being influenced

743
00:40:27,719 --> 00:40:30,440
Speaker 1: by our Sun, right, yeah, probably, and it's probably been

744
00:40:30,480 --> 00:40:33,720
Speaker 1: falling in towards the Sun for a long long time.

745
00:40:34,160 --> 00:40:36,440
Speaker 1: They estimate that the period of this commet is about

746
00:40:36,520 --> 00:40:40,279
Speaker 1: three million years. It's gonna take three million years to

747
00:40:40,320 --> 00:40:43,399
Speaker 1: loop around go back out into the really far reach

748
00:40:43,440 --> 00:40:45,439
Speaker 1: of the Solar System, where it's going to start moving

749
00:40:45,520 --> 00:40:49,080
Speaker 1: really really slow. Right, People think about things moving fast

750
00:40:49,120 --> 00:40:51,160
Speaker 1: when they're far away from the Sun, but the opposite

751
00:40:51,239 --> 00:40:53,279
Speaker 1: is true when you're really close to the Sun. When

752
00:40:53,280 --> 00:40:56,440
Speaker 1: you're moving really really fast, like Mercury's orbit is very fast,

753
00:40:56,760 --> 00:41:00,320
Speaker 1: Pluto plunks along very very slowly because it's far away

754
00:41:00,320 --> 00:41:02,719
Speaker 1: from the Sun, which means that the Sun's gravity is

755
00:41:02,719 --> 00:41:04,640
Speaker 1: not very strong, so it doesn't have to be moving

756
00:41:04,760 --> 00:41:06,879
Speaker 1: very fast to be in an orbit, in the same

757
00:41:06,920 --> 00:41:09,120
Speaker 1: way a commet. When it zooms towards the center of

758
00:41:09,120 --> 00:41:11,800
Speaker 1: the Solar system, it's going really fast as it whips

759
00:41:11,840 --> 00:41:14,920
Speaker 1: around the Sun, and then it slows down as it

760
00:41:14,960 --> 00:41:16,759
Speaker 1: gets far out. It's sort of like a ball in

761
00:41:16,760 --> 00:41:19,200
Speaker 1: a well. It zooms down, it's going it's fastest at

762
00:41:19,200 --> 00:41:21,799
Speaker 1: the bottom, and then when it comes back up and

763
00:41:21,840 --> 00:41:24,479
Speaker 1: before it turns around, it's like stops. It's the same

764
00:41:24,520 --> 00:41:26,720
Speaker 1: thing with a commet. And so it takes three million

765
00:41:26,840 --> 00:41:29,279
Speaker 1: years to do this whole orbit, all the way deep

766
00:41:29,320 --> 00:41:31,960
Speaker 1: into the or cloud and then back in towards the Sun.

767
00:41:32,160 --> 00:41:35,399
Speaker 1: But well, we actually get to see it. If it's

768
00:41:35,440 --> 00:41:37,520
Speaker 1: eleven au away, we will get to see it, but

769
00:41:37,520 --> 00:41:39,920
Speaker 1: we'll have to use telescopes, so you won't be able

770
00:41:39,960 --> 00:41:41,719
Speaker 1: to see it with your naked eye. Even though this

771
00:41:41,800 --> 00:41:45,560
Speaker 1: thing is a monster, right, it's like almost two kilometers across,

772
00:41:45,840 --> 00:41:48,680
Speaker 1: it's gonna be too far away for us to spot it.

773
00:41:48,800 --> 00:41:50,640
Speaker 1: The comments that you can see with the naked eye,

774
00:41:50,640 --> 00:41:53,520
Speaker 1: Gailey's comet and other stuff, that's because they come close

775
00:41:53,640 --> 00:41:55,640
Speaker 1: enough to the Earth that you can really see them.

776
00:41:55,719 --> 00:41:57,279
Speaker 1: But you will be able to see this thing with

777
00:41:57,360 --> 00:42:00,239
Speaker 1: an amateur telescope, and they suspect that it might grow

778
00:42:00,280 --> 00:42:02,640
Speaker 1: a tail. Right now, it just has a coma, but

779
00:42:02,719 --> 00:42:04,839
Speaker 1: as it gets closer and closer to the Sun, it's

780
00:42:04,880 --> 00:42:07,040
Speaker 1: gonna get heated up more and more and it might

781
00:42:07,080 --> 00:42:09,920
Speaker 1: develop this gas tail or a dust tail. So that

782
00:42:09,920 --> 00:42:13,359
Speaker 1: would be pretty useful also because studying that tail can

783
00:42:13,400 --> 00:42:16,400
Speaker 1: help us understand what is out there in the Orc cloud.

784
00:42:16,719 --> 00:42:18,680
Speaker 1: What can the tail tell us about the Orc cloud?

785
00:42:18,840 --> 00:42:21,000
Speaker 1: So we don't know what the stuff out there is

786
00:42:21,040 --> 00:42:23,200
Speaker 1: made out if we think it's like ice and rock,

787
00:42:23,560 --> 00:42:26,080
Speaker 1: and we really want to build better models of how

788
00:42:26,120 --> 00:42:28,799
Speaker 1: the solar system forms so we can understand what is

789
00:42:28,880 --> 00:42:31,720
Speaker 1: out there, and so we can take measurements of what's

790
00:42:31,760 --> 00:42:34,839
Speaker 1: in this tail even without going out there. Like when

791
00:42:34,880 --> 00:42:37,279
Speaker 1: an object is just frozen, all you can do is

792
00:42:37,280 --> 00:42:39,319
Speaker 1: bounce light off of it and measure like how much

793
00:42:39,400 --> 00:42:41,400
Speaker 1: light reflects. But if you have vapor, if you have

794
00:42:41,520 --> 00:42:44,399
Speaker 1: gas and light passes through it, then you can tell

795
00:42:44,440 --> 00:42:46,640
Speaker 1: a lot more about what's in it because you can

796
00:42:46,680 --> 00:42:49,080
Speaker 1: look at the frequency of light that passes through it,

797
00:42:49,200 --> 00:42:52,520
Speaker 1: and it will also glow in its own frequencies, just

798
00:42:52,560 --> 00:42:55,279
Speaker 1: like you can tell what's in the atmosphere of Venus

799
00:42:55,320 --> 00:42:57,879
Speaker 1: by looking at the frequencies of light that passed through

800
00:42:57,920 --> 00:43:01,240
Speaker 1: it and the frequencies in which that gas loows, because remember,

801
00:43:01,480 --> 00:43:04,400
Speaker 1: every kind of gas glows in different frequencies, is like

802
00:43:04,400 --> 00:43:07,279
Speaker 1: a little fingerprint based on which kinds of photons it

803
00:43:07,360 --> 00:43:10,279
Speaker 1: likes to absorb in which kinds it likes to give off. So,

804
00:43:10,360 --> 00:43:13,279
Speaker 1: because the comet is visiting closer to the Sun and

805
00:43:13,400 --> 00:43:16,440
Speaker 1: some of its icy components are being turned into gas,

806
00:43:16,640 --> 00:43:19,520
Speaker 1: we can then study that tail and try to understand like, oh,

807
00:43:19,640 --> 00:43:22,359
Speaker 1: how much methane is there, or how much carbon is there,

808
00:43:22,360 --> 00:43:25,279
Speaker 1: how much oxygen is there in these frozen objects, and

809
00:43:25,280 --> 00:43:28,600
Speaker 1: that will really inform the models we build about how

810
00:43:28,640 --> 00:43:31,080
Speaker 1: the Ord Cloud came to be and where everything is

811
00:43:31,120 --> 00:43:34,080
Speaker 1: distributed in the Solar system, and it could maybe tell

812
00:43:34,160 --> 00:43:37,759
Speaker 1: us like how big the largest ice balls might be

813
00:43:37,800 --> 00:43:40,399
Speaker 1: in the Orc Club exactly. The more data we have

814
00:43:40,600 --> 00:43:43,600
Speaker 1: about these details, the better we can build our models

815
00:43:43,760 --> 00:43:46,920
Speaker 1: to really specifically predict what's out there in the Orc Cloud.

816
00:43:47,400 --> 00:43:50,080
Speaker 1: Because this is the biggest one we've seen, is it

817
00:43:50,160 --> 00:43:52,440
Speaker 1: likely that it's the biggest thing in the Orc Cloud?

818
00:43:52,680 --> 00:43:56,799
Speaker 1: Almost certainly? Not right, Probably there are many more of

819
00:43:56,840 --> 00:44:00,400
Speaker 1: these things waiting out there to fuse different culture together

820
00:44:00,480 --> 00:44:03,480
Speaker 1: as astronomers from around the world come together to find them.

821
00:44:03,520 --> 00:44:06,000
Speaker 1: But there are probably much bigger ones that we just

822
00:44:06,080 --> 00:44:09,680
Speaker 1: have not seen yet. So mark down on your calendars

823
00:44:09,920 --> 00:44:14,600
Speaker 1: nine years from now, get your telescopes out, and start

824
00:44:14,640 --> 00:44:17,560
Speaker 1: looking at that comment. Hunh exactly. And another fun way

825
00:44:17,600 --> 00:44:20,600
Speaker 1: to think about commets is not just the size of

826
00:44:20,640 --> 00:44:24,359
Speaker 1: their central object, like we're talking about the icy, frozen core,

827
00:44:24,480 --> 00:44:27,080
Speaker 1: like how much stuff there is to the commet, which is,

828
00:44:27,200 --> 00:44:28,759
Speaker 1: you know, a useful way to think about it if

829
00:44:28,760 --> 00:44:31,319
Speaker 1: you're worried about the comets hitting the planet. But there's

830
00:44:31,360 --> 00:44:33,440
Speaker 1: another way you can measure the size of the comment,

831
00:44:33,760 --> 00:44:36,160
Speaker 1: and that's by the size of the coma. They make

832
00:44:36,440 --> 00:44:39,640
Speaker 1: this gaseous envelope that surrounds the commet. As it gets

833
00:44:39,640 --> 00:44:43,400
Speaker 1: heated up, some of these things get like crazy big,

834
00:44:43,680 --> 00:44:47,600
Speaker 1: it's ridiculous, it's bonkers. These things are not gravitationally bound.

835
00:44:47,600 --> 00:44:49,680
Speaker 1: They're just sort of like surrounding the comet. But they

836
00:44:49,680 --> 00:44:52,719
Speaker 1: can eject so much gas that their commas can be

837
00:44:52,760 --> 00:44:55,640
Speaker 1: like enormous. There's a comment they found in two thousand

838
00:44:55,760 --> 00:44:59,799
Speaker 1: seven called commet homes that has a really tiny, small core,

839
00:45:00,160 --> 00:45:02,640
Speaker 1: but it's coma. Get ready for this because it's gonna

840
00:45:02,640 --> 00:45:06,280
Speaker 1: sound insane. It's coma is bigger than the sun. Shut

841
00:45:06,320 --> 00:45:08,840
Speaker 1: the front door of the cellar for the system, and

842
00:45:08,880 --> 00:45:11,200
Speaker 1: don't let any of these ens. So how can it

843
00:45:11,360 --> 00:45:13,840
Speaker 1: produce if it's got a small core, how can it

844
00:45:13,880 --> 00:45:18,080
Speaker 1: produce such a huge cloud of gas? And don't say cuteoba,

845
00:45:18,160 --> 00:45:22,560
Speaker 1: because I won't believe you. Exactly that's the problem with

846
00:45:22,680 --> 00:45:26,360
Speaker 1: being flavored ice cream exactly for Jolie gelato, not a

847
00:45:26,400 --> 00:45:29,960
Speaker 1: good idea. Nobody knows really, and it's a question about

848
00:45:30,000 --> 00:45:31,680
Speaker 1: like what is this thing made out of and how

849
00:45:31,719 --> 00:45:34,319
Speaker 1: did it do this? But they saw this comma. It's

850
00:45:34,480 --> 00:45:38,520
Speaker 1: one point four million kilometers wide. You can actually see

851
00:45:38,560 --> 00:45:41,400
Speaker 1: it in our skies. It's like a big circular cloud.

852
00:45:41,520 --> 00:45:43,600
Speaker 1: So we don't really understand it. The core of this thing,

853
00:45:43,680 --> 00:45:47,520
Speaker 1: common homes is just four kilometers in diameter, and it

854
00:45:47,600 --> 00:45:51,520
Speaker 1: made this enormous coma. So it could be something about

855
00:45:51,560 --> 00:45:54,080
Speaker 1: what that common is made out of, or maybe how

856
00:45:54,160 --> 00:45:56,600
Speaker 1: it was layered. You know, if you get layers in

857
00:45:56,680 --> 00:45:59,040
Speaker 1: just the right way, you can get like explosive release

858
00:45:59,080 --> 00:46:02,400
Speaker 1: of energy than like a gradual release. We're just building

859
00:46:02,400 --> 00:46:05,160
Speaker 1: models and trying to understand it. It's fascinating. And that's

860
00:46:05,200 --> 00:46:06,840
Speaker 1: why it's so much fun to look up at the

861
00:46:06,920 --> 00:46:09,120
Speaker 1: night sky, because, as we were saying earlier, there are

862
00:46:09,160 --> 00:46:11,960
Speaker 1: always surprises. We're gonna make a model of what's in

863
00:46:12,000 --> 00:46:14,040
Speaker 1: the work clad and what the biggest thing out there is,

864
00:46:14,280 --> 00:46:17,120
Speaker 1: and then five years later it's gonna say, I got

865
00:46:17,120 --> 00:46:19,640
Speaker 1: a bigger one for you. How long could something like

866
00:46:19,680 --> 00:46:22,759
Speaker 1: that last? Like, if you have a small core and

867
00:46:22,840 --> 00:46:26,440
Speaker 1: it's exuding so much gas in this giant ball, it

868
00:46:26,480 --> 00:46:28,759
Speaker 1: can't launch that long, right, It's got to be sort

869
00:46:28,760 --> 00:46:31,160
Speaker 1: of a flash in a pan. Yeah, it can't laughs

870
00:46:31,160 --> 00:46:34,040
Speaker 1: out long exactly because the Sun is constantly stripping it

871
00:46:34,160 --> 00:46:37,920
Speaker 1: of this gas. To maintain it has to continuously evaporate

872
00:46:38,200 --> 00:46:41,239
Speaker 1: or sublimate more and more gas. And actually some of

873
00:46:41,239 --> 00:46:44,880
Speaker 1: the things in the asteroid belt they think are dead comets.

874
00:46:45,200 --> 00:46:48,640
Speaker 1: Comets that used to be rocks surrounded by ice that

875
00:46:48,680 --> 00:46:51,440
Speaker 1: flew around the sun, blew up all of that ice

876
00:46:51,560 --> 00:46:54,640
Speaker 1: into a coma and are now just totally stripped and

877
00:46:54,640 --> 00:46:57,960
Speaker 1: are just dead rocks. And so now they're called asteroids

878
00:46:57,960 --> 00:47:00,760
Speaker 1: because they no longer have a coma. So a comet

879
00:47:01,040 --> 00:47:03,600
Speaker 1: is like a transitional period in the life of a

880
00:47:03,680 --> 00:47:05,759
Speaker 1: Solar System object. You can be a comet for a

881
00:47:05,760 --> 00:47:08,719
Speaker 1: while and then eventually you get downgraded to an asteroid

882
00:47:08,920 --> 00:47:11,719
Speaker 1: when you've blown all of your gas. I'm trying to

883
00:47:11,760 --> 00:47:15,200
Speaker 1: imagine what it would be like to sort of pass

884
00:47:15,400 --> 00:47:19,879
Speaker 1: through that coma of a comet. Would it be like

885
00:47:20,239 --> 00:47:25,160
Speaker 1: you're in the swirling world of like chunks of ice

886
00:47:25,440 --> 00:47:30,440
Speaker 1: and gases. Would you immediately be sort of pulverized by

887
00:47:30,480 --> 00:47:33,839
Speaker 1: these little particles being shooting out from it? What would

888
00:47:33,840 --> 00:47:37,440
Speaker 1: that experience be like being in the coma of a comet.

889
00:47:37,840 --> 00:47:41,080
Speaker 1: It's not nearly as dense as our atmosphere. It's very

890
00:47:41,200 --> 00:47:44,040
Speaker 1: very dilute in comparison, and so it's nothing like being

891
00:47:44,200 --> 00:47:46,719
Speaker 1: in air, but it is more dense than the rest

892
00:47:46,719 --> 00:47:48,479
Speaker 1: of space. And so one thing you have to worry

893
00:47:48,480 --> 00:47:51,560
Speaker 1: about is the velocity. If there are dust greens in

894
00:47:51,600 --> 00:47:54,040
Speaker 1: this tail or, in this coma that are moving at

895
00:47:54,120 --> 00:47:57,160
Speaker 1: high speeds, they can carry a lot of kinetic energy

896
00:47:57,640 --> 00:48:00,279
Speaker 1: and they could, you know, hold your spaceship. We talked

897
00:48:00,320 --> 00:48:02,360
Speaker 1: about is actually on the podcast recently, about how to

898
00:48:02,520 --> 00:48:06,800
Speaker 1: protect ships from high speed micro meteorites or death grains.

899
00:48:06,880 --> 00:48:09,040
Speaker 1: It's a challenge, but we have sent stuff up there.

900
00:48:09,080 --> 00:48:13,200
Speaker 1: We have sent probes to comets. We had Rosetta, which

901
00:48:13,440 --> 00:48:17,560
Speaker 1: landed on a comet, and then NASA sent Deep Impact,

902
00:48:17,600 --> 00:48:20,440
Speaker 1: which actually blasted a crater off of a comet to

903
00:48:20,480 --> 00:48:22,560
Speaker 1: try to study what it was made out of. So

904
00:48:22,600 --> 00:48:25,839
Speaker 1: you can send spaceships up to like intercept commets and

905
00:48:25,920 --> 00:48:29,160
Speaker 1: study them. It's pretty awesome. What did Rosetta and Deep

906
00:48:29,200 --> 00:48:32,080
Speaker 1: Impact find? Like were they able to get some kind

907
00:48:32,080 --> 00:48:34,840
Speaker 1: of samples of what the comets were made out of

908
00:48:34,880 --> 00:48:37,240
Speaker 1: and bring them back to Earth. So there currently aren't

909
00:48:37,280 --> 00:48:40,120
Speaker 1: any samples from comets that have returned to Earth. But

910
00:48:40,160 --> 00:48:42,960
Speaker 1: they did send these missions out there and they studied them,

911
00:48:43,040 --> 00:48:44,719
Speaker 1: and they tried to understand, like, you know, what is

912
00:48:44,760 --> 00:48:47,160
Speaker 1: the geology of this thing? And the thing that surprises

913
00:48:47,200 --> 00:48:49,480
Speaker 1: me the most is that looking at the surface of

914
00:48:49,480 --> 00:48:52,160
Speaker 1: these things, they just sort of look like big rocks.

915
00:48:52,360 --> 00:48:55,120
Speaker 1: They're sort of familiar, like they look like a big

916
00:48:55,200 --> 00:48:58,280
Speaker 1: rocky you would see sitting on the ground in Joshua

917
00:48:58,320 --> 00:49:01,279
Speaker 1: tree or you know, near some are like volcano or something.

918
00:49:01,280 --> 00:49:04,919
Speaker 1: They're sort of familiar looking objects. They're not otherworldly at all.

919
00:49:05,280 --> 00:49:08,000
Speaker 1: They have weird shapes and each one tells its history,

920
00:49:08,040 --> 00:49:10,160
Speaker 1: but we're still sort of studying the data from deep

921
00:49:10,200 --> 00:49:13,640
Speaker 1: Impact and from Rosetta to understand like the deep geology

922
00:49:13,680 --> 00:49:17,279
Speaker 1: of what's in those comments. Do those probes remain on

923
00:49:17,400 --> 00:49:20,560
Speaker 1: the commets forever and just send us back this data.

924
00:49:20,800 --> 00:49:22,880
Speaker 1: They don't last very long. One of them was orbiting

925
00:49:22,880 --> 00:49:25,360
Speaker 1: the commet for a while and then sent down a lander,

926
00:49:25,400 --> 00:49:27,360
Speaker 1: and the lander didn't last for very long. It like

927
00:49:27,640 --> 00:49:29,640
Speaker 1: took a little bit of data and then sort of

928
00:49:29,680 --> 00:49:31,960
Speaker 1: died and the orbitter was able to take a picture

929
00:49:31,960 --> 00:49:34,839
Speaker 1: of it dead on the surface of the commet. So sad,

930
00:49:35,400 --> 00:49:38,200
Speaker 1: so sad. But yeah, these things don't last very long,

931
00:49:38,520 --> 00:49:40,960
Speaker 1: all right. So that's a little tour of what's going

932
00:49:41,000 --> 00:49:44,200
Speaker 1: on out there in the deep edges of the Solar System,

933
00:49:44,320 --> 00:49:47,480
Speaker 1: including some surprises. There are comments out there that are

934
00:49:47,520 --> 00:49:50,680
Speaker 1: bigger than a bus, bigger than many school buses, bigger

935
00:49:50,719 --> 00:49:54,480
Speaker 1: than maybe even millions of blue whales all packed together.

936
00:49:55,040 --> 00:49:57,200
Speaker 1: And so as usual, the thing that I love is

937
00:49:57,239 --> 00:50:00,839
Speaker 1: discovering that there are surprises out there in space, not

938
00:50:00,960 --> 00:50:04,200
Speaker 1: just super far away, but here in our backyard. And

939
00:50:04,239 --> 00:50:07,200
Speaker 1: that's really fun because it means we can learn the answers.

940
00:50:07,560 --> 00:50:10,120
Speaker 1: We don't have to rely on aliens coming to visit

941
00:50:10,160 --> 00:50:12,080
Speaker 1: to tell us the deep secrets of the universe. We

942
00:50:12,120 --> 00:50:14,600
Speaker 1: could actually send more probes out there and explore the

943
00:50:14,680 --> 00:50:17,799
Speaker 1: rac cloud, build more space telescopes and get better pictures.

944
00:50:17,840 --> 00:50:20,160
Speaker 1: These are things that we will know the answers to

945
00:50:20,480 --> 00:50:23,399
Speaker 1: In a hundred years, astronomers will know so much more

946
00:50:23,400 --> 00:50:25,719
Speaker 1: about the far reaches of the Solar System, and they'll

947
00:50:25,760 --> 00:50:27,640
Speaker 1: look back and think of us as living in the

948
00:50:27,719 --> 00:50:30,880
Speaker 1: dark ages. And I'm just totally happy that there's a

949
00:50:30,880 --> 00:50:34,719
Speaker 1: big cloud of mysterious giant ice balls of which we

950
00:50:35,040 --> 00:50:37,840
Speaker 1: do not know the maximum size. I think that's great

951
00:50:37,880 --> 00:50:42,520
Speaker 1: and perfectly fine. I'll sleep like a baby tonight, have

952
00:50:42,600 --> 00:50:47,440
Speaker 1: an feather spoonful of gelato, and just enjoy your life. Katie.

953
00:50:47,840 --> 00:50:50,080
Speaker 1: All right, well, thanks Katie very much for joining us today.

954
00:50:50,280 --> 00:50:52,239
Speaker 1: Thank you for having me, and thanks to all of

955
00:50:52,239 --> 00:51:02,160
Speaker 1: you for listening to and in next time, ye thanks

956
00:51:02,200 --> 00:51:04,880
Speaker 1: for listening, and remember that Daniel and Jorge Explain the

957
00:51:04,920 --> 00:51:08,040
Speaker 1: Universe is a production of I Heart Radio. For more

958
00:51:08,120 --> 00:51:11,480
Speaker 1: podcast for my Heart Radio, visit the I Heart Radio app,

959
00:51:11,760 --> 00:51:15,200
Speaker 1: Apple Podcasts, or wherever you listen to your favorite shows.

960
00:51:16,160 --> 00:51:16,200
Speaker 1: H