1 00:00:08,440 --> 00:00:12,640 Speaker 1: Hey, Jorgey, what's your favorite Solar System object? I'm gonna 2 00:00:12,680 --> 00:00:14,960 Speaker 1: have to go with the Earth because you know, it's 3 00:00:14,960 --> 00:00:17,360 Speaker 1: the only one I've been to, so you're not a 4 00:00:17,440 --> 00:00:20,520 Speaker 1: gas giant kind of person. Depends how many tacas I 5 00:00:20,560 --> 00:00:22,599 Speaker 1: had for munch. But what if I do? You do 6 00:00:22,640 --> 00:00:24,480 Speaker 1: you have a favorite? I'm a big fan of the 7 00:00:24,520 --> 00:00:27,280 Speaker 1: Sun and everything it does for us here on Earth, 8 00:00:27,440 --> 00:00:31,040 Speaker 1: But my favorite thing in the Solar System is actually comets. 9 00:00:31,160 --> 00:00:34,239 Speaker 1: Comments what have commets done for us? Well, they're like 10 00:00:34,400 --> 00:00:38,480 Speaker 1: cosmic snowballs, and actually most of Earth's water turns out 11 00:00:38,479 --> 00:00:41,960 Speaker 1: to be melted comets. I guess water is pretty useful 12 00:00:42,080 --> 00:00:44,479 Speaker 1: to have. But wait, are you saying the Solar System 13 00:00:44,520 --> 00:00:48,280 Speaker 1: is having a snowball fight. Yeah, it's more like deadly 14 00:00:48,520 --> 00:01:07,640 Speaker 1: planetary dodgeball. Hi am more Hammon, cartoonists and the creator 15 00:01:07,720 --> 00:01:11,400 Speaker 1: of PhD Comics. Hi. I'm Daniel. I'm a particle physicist, 16 00:01:11,440 --> 00:01:15,120 Speaker 1: but I have strong opinions about various Solar System objects. 17 00:01:15,120 --> 00:01:18,160 Speaker 1: And Welcome to our podcast, Daniel and Jorge Explain the Universe, 18 00:01:18,240 --> 00:01:20,479 Speaker 1: a production of I Heart Radio in which we talk 19 00:01:20,520 --> 00:01:23,160 Speaker 1: about everything that we know about the universe and everything 20 00:01:23,160 --> 00:01:25,559 Speaker 1: that we don't know about the universe, everything that makes 21 00:01:25,640 --> 00:01:28,759 Speaker 1: us wonder and everything that makes us go huh. And 22 00:01:28,800 --> 00:01:31,480 Speaker 1: we explain all of it to you because we think 23 00:01:31,520 --> 00:01:35,200 Speaker 1: that your curiosity is as valuable as the curiosity of 24 00:01:35,240 --> 00:01:38,120 Speaker 1: scientists working on the front line. Yeah, and there's a 25 00:01:38,120 --> 00:01:41,040 Speaker 1: lot to be curious about. The universe is full of 26 00:01:41,080 --> 00:01:44,680 Speaker 1: amazing and incredible things and a lot of mysteries, a 27 00:01:44,680 --> 00:01:48,240 Speaker 1: lot of things that we don't know where they come from, 28 00:01:48,320 --> 00:01:51,800 Speaker 1: or what makes them what they are, or why they're there. Yeah, 29 00:01:51,840 --> 00:01:55,200 Speaker 1: And a lot of great scientific discoveries begin with pretty 30 00:01:55,240 --> 00:01:58,280 Speaker 1: simple questions, you know, like why is that thing there? 31 00:01:58,680 --> 00:02:01,040 Speaker 1: Or why are those common? It's flying through space and 32 00:02:01,040 --> 00:02:03,120 Speaker 1: where do they come from? Is one of them going 33 00:02:03,160 --> 00:02:06,480 Speaker 1: to hit us and wipe us out? Great scientific discoveries 34 00:02:06,560 --> 00:02:09,640 Speaker 1: come from really simple questions that everybody wants to know 35 00:02:09,720 --> 00:02:12,280 Speaker 1: the answers to. Yeah, because we have questions even about 36 00:02:12,280 --> 00:02:16,679 Speaker 1: our own backyard. Our solar system is still full of 37 00:02:16,720 --> 00:02:20,560 Speaker 1: things that we don't quite fully understand. People like to 38 00:02:20,600 --> 00:02:23,120 Speaker 1: talk about things in the distant universe that are still 39 00:02:23,160 --> 00:02:25,000 Speaker 1: a mystery. We don't know how big it is or 40 00:02:25,040 --> 00:02:27,720 Speaker 1: what's going on out there in the depths of the universe. 41 00:02:28,080 --> 00:02:30,600 Speaker 1: But you're absolutely right, there's still a lot to be 42 00:02:30,680 --> 00:02:34,919 Speaker 1: discovered right in our own neighborhood, big questions about what's 43 00:02:34,919 --> 00:02:38,120 Speaker 1: going on in our own household that we still don't 44 00:02:38,160 --> 00:02:39,840 Speaker 1: know the answers to. So they know you have a 45 00:02:39,960 --> 00:02:42,760 Speaker 1: strong opinions about things in our Solar System? Are they 46 00:02:42,800 --> 00:02:45,840 Speaker 1: all positive or are some of them negative? Is there 47 00:02:45,840 --> 00:02:49,440 Speaker 1: someone you don't like here in system? Now? They're all positive. 48 00:02:49,480 --> 00:02:52,799 Speaker 1: I love everything in the Solar System, from ice giants 49 00:02:52,840 --> 00:02:57,720 Speaker 1: to planetism als, to space centaurs, to deadly comments to 50 00:02:57,880 --> 00:03:00,919 Speaker 1: enormous burning balls of gas. I just think it's all 51 00:03:01,000 --> 00:03:04,560 Speaker 1: pretty awesome. I can't imagine having a negative opinion about anything. 52 00:03:04,960 --> 00:03:09,679 Speaker 1: Do you include in that all the people on Earth too? Yes? 53 00:03:09,919 --> 00:03:12,880 Speaker 1: I love everybody. No, it's incredible when you look out 54 00:03:12,880 --> 00:03:16,280 Speaker 1: there in space that you see so many beautiful, amazing things. 55 00:03:16,280 --> 00:03:18,040 Speaker 1: Like when was the last time you looked at something 56 00:03:18,080 --> 00:03:20,040 Speaker 1: out in space and you thought that's just kind of 57 00:03:21,000 --> 00:03:23,480 Speaker 1: you know, it's all just sort of like incredible and beautiful. 58 00:03:23,560 --> 00:03:26,919 Speaker 1: You know, whoever the universe's visual artist is, they're doing 59 00:03:26,919 --> 00:03:29,440 Speaker 1: a good job. Although you know, we live in California, 60 00:03:29,480 --> 00:03:31,200 Speaker 1: so right now, when I look up at the sky, 61 00:03:31,600 --> 00:03:34,080 Speaker 1: it's mostly smoke. Well, then take a journey through the 62 00:03:34,080 --> 00:03:36,120 Speaker 1: Solar System with your mind's eye. Yeah, there are a 63 00:03:36,160 --> 00:03:38,800 Speaker 1: lot of big questions about the Solar System and how 64 00:03:38,840 --> 00:03:40,560 Speaker 1: we got to where we are. And one of those 65 00:03:40,680 --> 00:03:44,640 Speaker 1: big questions about our Solar system is where do comets 66 00:03:44,760 --> 00:03:48,080 Speaker 1: come from? We don't know a comet factory here in 67 00:03:48,080 --> 00:03:49,920 Speaker 1: our Solar system, do we We don't know of a 68 00:03:50,080 --> 00:03:52,720 Speaker 1: comet factory. It could be that there are aliens out 69 00:03:52,720 --> 00:03:55,160 Speaker 1: there in the outskirts of the Solar System packing up 70 00:03:55,200 --> 00:03:58,800 Speaker 1: ice balls and shooting them at Earth. Or it could 71 00:03:58,800 --> 00:04:01,720 Speaker 1: be that they come from something else, something deep out 72 00:04:01,720 --> 00:04:05,080 Speaker 1: there in the Solar System. That's basically a huge reservoir 73 00:04:05,120 --> 00:04:08,800 Speaker 1: of comets ready to fall in, screaming towards the Sun 74 00:04:09,040 --> 00:04:11,880 Speaker 1: and boiling. And this is a big question because some 75 00:04:11,920 --> 00:04:14,560 Speaker 1: people think that most of the water on Earth came 76 00:04:14,680 --> 00:04:18,320 Speaker 1: from comets. That's right, Commets are mostly ice. You know, 77 00:04:18,400 --> 00:04:21,200 Speaker 1: something a lot of people don't understand about the universe 78 00:04:21,600 --> 00:04:24,960 Speaker 1: is that water is not rare. We talk about liquid 79 00:04:25,000 --> 00:04:27,200 Speaker 1: water being something we're looking for in the surface of 80 00:04:27,240 --> 00:04:30,080 Speaker 1: planets to see if there's alien life, but water as 81 00:04:30,080 --> 00:04:32,560 Speaker 1: a chemical, there's tons of it out there. There's like 82 00:04:32,680 --> 00:04:37,039 Speaker 1: planet size blobs of it. So most comets are icy 83 00:04:37,120 --> 00:04:40,360 Speaker 1: planetism alls. They're just big balls of ice, and some 84 00:04:40,440 --> 00:04:43,200 Speaker 1: of them fell towards the Earth in the early days 85 00:04:43,600 --> 00:04:47,600 Speaker 1: and landed and melted and formed our oceans. Thank goodness, 86 00:04:47,600 --> 00:04:50,440 Speaker 1: because that's where life came from. Right, we had them 87 00:04:50,440 --> 00:04:53,040 Speaker 1: in for those snowballs, and we wouldn't be here, that's right. 88 00:04:53,279 --> 00:04:55,640 Speaker 1: So next time you put your lips to a glass 89 00:04:55,680 --> 00:05:00,000 Speaker 1: of melted comet, remember you're drinking. The outer Solar System 90 00:05:00,000 --> 00:05:04,320 Speaker 1: are melted common Right, next time you go somewhere in 91 00:05:04,400 --> 00:05:06,960 Speaker 1: order a drink, order sparkling melted comment and see what 92 00:05:07,000 --> 00:05:08,960 Speaker 1: they do. Yeah, So a big question is where they 93 00:05:09,000 --> 00:05:12,479 Speaker 1: come from, and so scientists have a potential answer to 94 00:05:12,560 --> 00:05:15,320 Speaker 1: that question, right, Daniel, that's right. They don't know for sure. 95 00:05:15,440 --> 00:05:18,720 Speaker 1: Nobody's ever actually seen it, but we've given it a name. 96 00:05:18,800 --> 00:05:21,160 Speaker 1: So today on the podcast, we will be asking the question, 97 00:05:25,680 --> 00:05:28,919 Speaker 1: what is now Daniel? Is that pronounced or or or 98 00:05:29,080 --> 00:05:32,679 Speaker 1: because it's spelled O r T. It's a great question, 99 00:05:33,080 --> 00:05:35,719 Speaker 1: and it's a Dutch name. It comes from a Dutch 100 00:05:35,720 --> 00:05:38,760 Speaker 1: astronomer who first thought it up. And so I reached 101 00:05:38,760 --> 00:05:42,360 Speaker 1: out to my Dutch speaking brother to ask him for 102 00:05:42,440 --> 00:05:45,200 Speaker 1: his preferred pronunciation because I didn't know is it ort 103 00:05:45,440 --> 00:05:48,320 Speaker 1: ort ort or something like weird Dutch vowel that we 104 00:05:48,320 --> 00:05:51,080 Speaker 1: don't even have in English that can never be replicated? 105 00:05:51,120 --> 00:05:54,080 Speaker 1: Keep going, keep going? Well, you know there are vowels 106 00:05:54,080 --> 00:05:56,440 Speaker 1: in Danish that you know you can only replicate. You 107 00:05:56,480 --> 00:05:58,880 Speaker 1: get like punched in the gut in exactly the right way, 108 00:05:59,000 --> 00:06:03,599 Speaker 1: like you Dango speakers out there know what I'm talking about. 109 00:06:04,160 --> 00:06:06,720 Speaker 1: But it turns out that or its spelled o o 110 00:06:07,040 --> 00:06:11,240 Speaker 1: rt is pronounced like port. All right, So it's a 111 00:06:11,320 --> 00:06:13,880 Speaker 1: cloud apparently of some sort, and it's I'm guessing it's 112 00:06:13,920 --> 00:06:16,200 Speaker 1: out in space, and so the big question is how 113 00:06:16,200 --> 00:06:18,359 Speaker 1: many people out there know what it is and what 114 00:06:18,480 --> 00:06:22,880 Speaker 1: its significance is. That's right? So I pulled our listeners 115 00:06:22,880 --> 00:06:26,600 Speaker 1: who have volunteered to answer random questions over the Internet 116 00:06:26,680 --> 00:06:29,839 Speaker 1: from a businessist they've never met. If you'd like to 117 00:06:29,839 --> 00:06:34,160 Speaker 1: participate in such absurd commentary on our physical universe, please 118 00:06:34,240 --> 00:06:37,480 Speaker 1: write to me two questions at Daniel and Jorge dot com. 119 00:06:37,600 --> 00:06:40,680 Speaker 1: And thanks to everybody who shared your speculations. Think about 120 00:06:40,720 --> 00:06:42,599 Speaker 1: it for a second. If someone asked you what the 121 00:06:42,720 --> 00:06:46,720 Speaker 1: orc cloud is, what would you answer. Here's what people 122 00:06:46,760 --> 00:06:50,320 Speaker 1: had to say, The or Cloud is one of the 123 00:06:50,400 --> 00:06:55,760 Speaker 1: outermost regions of the Solar System, comprised of we think 124 00:06:55,760 --> 00:06:58,960 Speaker 1: a bunch of remnants of the early Solar system. The 125 00:06:59,200 --> 00:07:04,880 Speaker 1: Orc Cloud is a group of like dust and rocks 126 00:07:05,200 --> 00:07:11,440 Speaker 1: and asteroids and just material that's way outside are encircles 127 00:07:11,680 --> 00:07:15,880 Speaker 1: our whole Solar system. I think in a giant sphere, 128 00:07:16,160 --> 00:07:20,040 Speaker 1: or maybe just a circle. The art Cloud is a 129 00:07:20,160 --> 00:07:25,640 Speaker 1: vast array of comets and other such I see debris 130 00:07:26,000 --> 00:07:28,920 Speaker 1: forwarding around the Sun, very far away from the rest 131 00:07:28,920 --> 00:07:33,240 Speaker 1: of the planetary systems. I know that the Sun, it's 132 00:07:33,240 --> 00:07:38,000 Speaker 1: the middle of it, and it passes our solar systems, 133 00:07:38,000 --> 00:07:41,040 Speaker 1: so passes Pluto. Is it the big cloud of dust 134 00:07:41,160 --> 00:07:43,160 Speaker 1: that I'm spewing out the top and the bottom of 135 00:07:43,200 --> 00:07:45,960 Speaker 1: the Milky Way? I have anything to do with equippable? 136 00:07:46,640 --> 00:07:49,800 Speaker 1: Probably close to the Solar system. I think the art 137 00:07:49,840 --> 00:07:53,480 Speaker 1: Cloud is like an area outside the Solar system where 138 00:07:53,480 --> 00:07:58,280 Speaker 1: there are some icy objects. I'm not sure what, probably 139 00:07:59,200 --> 00:08:02,440 Speaker 1: comets and things like that. All right, some pretty good answers. 140 00:08:02,520 --> 00:08:05,240 Speaker 1: Most people seem to know it's something related to our 141 00:08:05,280 --> 00:08:08,320 Speaker 1: Solar system, and that it's a cloud, and that maybe 142 00:08:08,360 --> 00:08:12,320 Speaker 1: there's ice involved. Yeah, exactly, it's something big and fuzzy 143 00:08:12,360 --> 00:08:16,080 Speaker 1: and out there and cool. Cool. And my favorite thing 144 00:08:16,080 --> 00:08:18,160 Speaker 1: about the Orc cloud is at the acronym the O 145 00:08:18,400 --> 00:08:23,000 Speaker 1: C is the same as the place I live, Orange County, 146 00:08:23,600 --> 00:08:26,440 Speaker 1: except it's a little warmer, I think, a little warmer, 147 00:08:26,600 --> 00:08:29,760 Speaker 1: but it's also still very very cool. That's the first 148 00:08:29,760 --> 00:08:32,880 Speaker 1: time I've heard you give a compliment to the Orange 149 00:08:32,880 --> 00:08:36,720 Speaker 1: County there. I love Orange County. Best place in the 150 00:08:36,760 --> 00:08:39,800 Speaker 1: world to live. Seriously, what could you complain about? But 151 00:08:39,960 --> 00:08:42,319 Speaker 1: that's not the topic of today's podcast. We're talking about 152 00:08:42,360 --> 00:08:46,160 Speaker 1: the cosmic o C, the solar systems O C, not 153 00:08:46,240 --> 00:08:49,400 Speaker 1: calibornias o C and to uh, it's apparently something out 154 00:08:49,400 --> 00:08:51,920 Speaker 1: in space and so Daniel, let's step people through it. 155 00:08:52,240 --> 00:08:54,760 Speaker 1: So what is the orc Cloud? The orc cloud is 156 00:08:54,800 --> 00:09:01,000 Speaker 1: super awesome. It is a theoretical cloud of icy planetisml's 157 00:09:01,280 --> 00:09:04,480 Speaker 1: or many planets planetismal. Did you just make that up 158 00:09:04,559 --> 00:09:07,040 Speaker 1: or is that the actual science terms? Oh? Man, I 159 00:09:07,080 --> 00:09:08,840 Speaker 1: wish I could have made that word of there's something 160 00:09:08,960 --> 00:09:13,120 Speaker 1: wonderful about just saying that word planetismal. Right, but no, 161 00:09:13,240 --> 00:09:16,400 Speaker 1: planetismal is a mini planet and it's smaller than a 162 00:09:16,520 --> 00:09:19,160 Speaker 1: dwarf planet. Right, You've got planet dwarf planet, and then 163 00:09:19,280 --> 00:09:23,480 Speaker 1: planet Tismal. They couldn't just say mini planet. Well it's 164 00:09:23,480 --> 00:09:25,920 Speaker 1: sort of like Planetino, you know, that's what you do 165 00:09:25,960 --> 00:09:28,800 Speaker 1: with English planet Tito. And so it's a bunch of 166 00:09:28,840 --> 00:09:33,240 Speaker 1: these and they're really really far out there. Like if 167 00:09:33,240 --> 00:09:35,240 Speaker 1: you have the Solar system, you know, the Earth is 168 00:09:35,240 --> 00:09:38,800 Speaker 1: at one AU call an astronomical unit, and you go 169 00:09:38,960 --> 00:09:41,480 Speaker 1: really far out you get out to like Neptune and Pluto. 170 00:09:42,040 --> 00:09:45,240 Speaker 1: You have to go much, much, much further before you 171 00:09:45,240 --> 00:09:48,280 Speaker 1: get to the arch cloud. Is it even considered our 172 00:09:48,320 --> 00:09:51,360 Speaker 1: Solar system or is it technically outside of our Solar system? Yeah, 173 00:09:51,360 --> 00:09:54,560 Speaker 1: it's a great question. Most people consider the end of 174 00:09:54,559 --> 00:09:57,800 Speaker 1: our Solar system to be just under about a hundred 175 00:09:57,880 --> 00:10:02,120 Speaker 1: a U, where the sun radiation becomes dominated by the 176 00:10:02,160 --> 00:10:04,960 Speaker 1: galactic radiation. How you think of space is sort of 177 00:10:05,000 --> 00:10:08,559 Speaker 1: like empty, right, but actually it's filled with streaming particles. 178 00:10:08,559 --> 00:10:11,600 Speaker 1: The Sun is pumping out particles, not just photons, but 179 00:10:11,679 --> 00:10:14,680 Speaker 1: protons and electrons and all sorts of crazy stuff, and 180 00:10:14,760 --> 00:10:17,079 Speaker 1: it dominates the region around it with all of its 181 00:10:17,080 --> 00:10:20,760 Speaker 1: pulsating radiation. But the rest of the galaxy also has 182 00:10:20,760 --> 00:10:23,599 Speaker 1: a wind that's coming from all the other stars in 183 00:10:23,640 --> 00:10:26,280 Speaker 1: the central black hole. And all that crazy stuff. So 184 00:10:26,320 --> 00:10:28,960 Speaker 1: we define the edge of the Solar system it's called 185 00:10:28,960 --> 00:10:32,839 Speaker 1: the helio pause, as the place where the Sun's radiation 186 00:10:33,320 --> 00:10:36,440 Speaker 1: stops dominating the local environment and you're taken over by 187 00:10:36,440 --> 00:10:39,960 Speaker 1: the galactic wind. And that's like a hundred or so A. 188 00:10:40,440 --> 00:10:42,840 Speaker 1: It's like when our Sun becomes just another star kind 189 00:10:42,840 --> 00:10:45,760 Speaker 1: of yeah, exactly, and the wind from the rest of 190 00:10:45,760 --> 00:10:49,280 Speaker 1: the galaxy takes over the Sun's wind. And here again 191 00:10:49,400 --> 00:10:51,719 Speaker 1: wind we don't mean air, We just mean the particles 192 00:10:51,720 --> 00:10:54,520 Speaker 1: that it's shooting out. But the rac cloud starts like 193 00:10:54,640 --> 00:10:58,760 Speaker 1: ten times further out than that, like at a thousand 194 00:10:58,960 --> 00:11:02,520 Speaker 1: a U. Now it's just still sort of like bound 195 00:11:02,559 --> 00:11:04,920 Speaker 1: by the gravity of the Sun, or is it pretty 196 00:11:05,000 --> 00:11:08,520 Speaker 1: much like an independent thing from our solar system. It's 197 00:11:08,520 --> 00:11:11,120 Speaker 1: definitely bound by the gravity of the Sun. So if 198 00:11:11,120 --> 00:11:13,920 Speaker 1: you define the edge of the Solar system by the radiation, 199 00:11:14,200 --> 00:11:17,040 Speaker 1: it's like a hundred a U. But stuff that's further 200 00:11:17,120 --> 00:11:20,319 Speaker 1: out is still gravitationally bound to the Sun, but it's 201 00:11:20,360 --> 00:11:23,280 Speaker 1: a little bit loose. It's like a little fuzzy. It's 202 00:11:23,360 --> 00:11:25,880 Speaker 1: so far out from the Sun that it's not that 203 00:11:26,040 --> 00:11:29,240 Speaker 1: hard to knock something off and have an escape into 204 00:11:29,240 --> 00:11:33,960 Speaker 1: interstellar space, so it's not orbiting around us. It's sort 205 00:11:33,960 --> 00:11:36,439 Speaker 1: of like we're tugging them and it's tugging us. It's 206 00:11:36,480 --> 00:11:39,040 Speaker 1: definitely orbiting around us. Think of it like a huge 207 00:11:39,320 --> 00:11:42,600 Speaker 1: shell surrounding the Solar System. The other fascinating thing about 208 00:11:42,640 --> 00:11:45,120 Speaker 1: it is that it's not a disk, right, Most of 209 00:11:45,160 --> 00:11:47,400 Speaker 1: the stuff in the Solar System is a big disc, 210 00:11:47,480 --> 00:11:50,360 Speaker 1: it's flat. But the Orc Cloud, we think, is a sphere. 211 00:11:50,440 --> 00:11:53,480 Speaker 1: It's like totally surrounding the Solar System, and it goes 212 00:11:53,520 --> 00:11:56,040 Speaker 1: out really really far out to like a light year 213 00:11:56,120 --> 00:11:59,800 Speaker 1: maybe two light years of just this like cloud of 214 00:12:00,040 --> 00:12:03,520 Speaker 1: little frozen objects, and there could be like trillions of 215 00:12:03,559 --> 00:12:08,040 Speaker 1: the planetismal, trillions of planetism many planets I'm sorry, yeah, 216 00:12:08,200 --> 00:12:10,600 Speaker 1: planet titos. And it's sort of like calculus. You know, 217 00:12:10,600 --> 00:12:13,520 Speaker 1: in calculus, you sum over infinitismals and you get like 218 00:12:13,520 --> 00:12:16,160 Speaker 1: an actual quantity. In the same way, if you sum 219 00:12:16,200 --> 00:12:19,439 Speaker 1: over all the planetism als in the ord cloud, you 220 00:12:19,520 --> 00:12:22,319 Speaker 1: get a combined mass of stuff that's like five times 221 00:12:22,400 --> 00:12:25,280 Speaker 1: the mass of the Earth, but then again spread out 222 00:12:25,320 --> 00:12:27,920 Speaker 1: into like trillions of objects. It spread out not just 223 00:12:28,000 --> 00:12:31,120 Speaker 1: like wide but tall to like it's it's pretty diffuse 224 00:12:31,280 --> 00:12:34,360 Speaker 1: it's very diffuse, Like it's not like flying the millennium 225 00:12:34,400 --> 00:12:36,840 Speaker 1: falcon through an asteroid field. You gonna like dodge and 226 00:12:36,880 --> 00:12:39,880 Speaker 1: weave right, it's like, could we see something, like is 227 00:12:39,920 --> 00:12:43,720 Speaker 1: there one there? It's so far out there, it's mostly empty. 228 00:12:43,920 --> 00:12:46,600 Speaker 1: But again, they are gravitationally bound to the Sun and 229 00:12:46,640 --> 00:12:48,640 Speaker 1: they are orbiting the Sun. That's why they are in 230 00:12:48,679 --> 00:12:51,480 Speaker 1: a cloud around the Sun. It's not like just the 231 00:12:51,520 --> 00:12:54,160 Speaker 1: whole interstellar medium is filled with these objects. It's a 232 00:12:54,200 --> 00:12:56,680 Speaker 1: cloud of them. We think. Again, we think we don't 233 00:12:56,679 --> 00:12:58,840 Speaker 1: know for sure. We haven't seen them because they're so 234 00:12:58,880 --> 00:13:01,960 Speaker 1: small and far away, but we think that they're there 235 00:13:02,200 --> 00:13:04,319 Speaker 1: in this big blob around the size see, and it's 236 00:13:04,360 --> 00:13:07,520 Speaker 1: made up of like giant literally like giant balls of ice, 237 00:13:07,800 --> 00:13:11,280 Speaker 1: basically snowballs. How big, Well, each one could be like 238 00:13:11,360 --> 00:13:14,120 Speaker 1: bigger than a kilometer in size, So we think that 239 00:13:14,200 --> 00:13:16,200 Speaker 1: they're like trillions of them that are more than a 240 00:13:16,240 --> 00:13:20,080 Speaker 1: kilometer and maybe only billions that are twenty kilometers are larger. 241 00:13:20,480 --> 00:13:23,040 Speaker 1: But if you wanted to have a cosmic snowball fight, 242 00:13:23,120 --> 00:13:25,640 Speaker 1: that's like where your arsenal is, that's the best place 243 00:13:25,679 --> 00:13:28,200 Speaker 1: to go for the stockpile. Wow, So that's like, let 244 00:13:28,200 --> 00:13:30,679 Speaker 1: me see, that's like a snowball about the size of 245 00:13:30,920 --> 00:13:35,520 Speaker 1: Los Angeles right kilometers. Yeah, there are billions of frozen 246 00:13:35,559 --> 00:13:39,640 Speaker 1: Los Angeles is out there in the o C because 247 00:13:39,679 --> 00:13:42,959 Speaker 1: they are pretty cool, icy cool. They are pretty cool, 248 00:13:43,320 --> 00:13:45,800 Speaker 1: and if they weren't gravitationally bound to the Sun, they 249 00:13:45,800 --> 00:13:49,120 Speaker 1: would just sort of float away into space. But they 250 00:13:49,160 --> 00:13:51,800 Speaker 1: are bound there. They're floating around, but you know, it's 251 00:13:51,840 --> 00:13:55,720 Speaker 1: sort of loose, and so sometimes the thought is sometimes 252 00:13:55,800 --> 00:13:58,839 Speaker 1: something perturbs them and then they can get knocked out 253 00:13:58,840 --> 00:14:01,520 Speaker 1: of their very loose orbit and plummet towards the inner 254 00:14:01,520 --> 00:14:04,120 Speaker 1: Solar System because they're in a stable orbit. Is that 255 00:14:04,160 --> 00:14:07,160 Speaker 1: the idea is that they're like happily going around our 256 00:14:07,200 --> 00:14:11,640 Speaker 1: Sun in this huge, wide orbit, but sometimes they can 257 00:14:11,720 --> 00:14:14,160 Speaker 1: fall in. Yeah, we think it's probably stable and if 258 00:14:14,200 --> 00:14:17,040 Speaker 1: nothing perturbed them, they would just happily hang out there 259 00:14:17,080 --> 00:14:21,040 Speaker 1: really far away, staying frozen. But you know, we are 260 00:14:21,160 --> 00:14:24,320 Speaker 1: in a little neighborhood, and since it's sort of loosely 261 00:14:24,400 --> 00:14:27,240 Speaker 1: held by the Sun, it's not that hard to perturb them. 262 00:14:27,440 --> 00:14:31,280 Speaker 1: And you can have things like galactic tides that squeeze 263 00:14:31,320 --> 00:14:33,440 Speaker 1: the orac cloud and knock some of them out of orbit. 264 00:14:33,960 --> 00:14:35,880 Speaker 1: You mean from the center of the galaxy. Yeah, just 265 00:14:35,920 --> 00:14:38,760 Speaker 1: the way the Moon has a gravitational effect on the 266 00:14:38,800 --> 00:14:41,040 Speaker 1: water of the Earth. So as the Moon goes around 267 00:14:41,080 --> 00:14:43,640 Speaker 1: the Earth, it tugs on the oceans and causes tides. 268 00:14:44,040 --> 00:14:46,880 Speaker 1: We have a gravitational pull towards the center of the galaxy, 269 00:14:47,240 --> 00:14:49,240 Speaker 1: and that tends to tug on one part of the 270 00:14:49,320 --> 00:14:52,040 Speaker 1: Orc Cloud that's closer to it more than the rest 271 00:14:52,040 --> 00:14:54,360 Speaker 1: of the Orc clouds, so sort of extends it. And 272 00:14:54,360 --> 00:14:57,240 Speaker 1: then as we move around the center of the galaxy 273 00:14:57,360 --> 00:15:00,520 Speaker 1: very slowly, you know, hundreds of millions of years, the 274 00:15:00,560 --> 00:15:04,160 Speaker 1: direction of that tug changes, so it's a dynamic. So 275 00:15:04,200 --> 00:15:06,160 Speaker 1: as we move around the center of the galaxy, the 276 00:15:06,200 --> 00:15:09,280 Speaker 1: tides change, the galactic tides change. So are we right 277 00:15:09,320 --> 00:15:17,800 Speaker 1: now and high tide or lord tide. Well, we're at 278 00:15:17,840 --> 00:15:20,080 Speaker 1: the center of it right so we wouldn't feel it 279 00:15:20,080 --> 00:15:22,160 Speaker 1: at all. But there's a blob of the Orc cloud 280 00:15:22,200 --> 00:15:25,320 Speaker 1: that's always pointed towards the center of the galaxy that 281 00:15:25,360 --> 00:15:27,720 Speaker 1: would be at high tide. There's more objects in that 282 00:15:27,880 --> 00:15:30,240 Speaker 1: part of it, so we're sort of at the very 283 00:15:30,240 --> 00:15:33,040 Speaker 1: center of it, so we can't tell, but it can 284 00:15:33,120 --> 00:15:36,320 Speaker 1: be galactic tides. It can also be like nearby stars. 285 00:15:36,760 --> 00:15:39,720 Speaker 1: If a nearby star happens to come somewhere close to 286 00:15:39,840 --> 00:15:42,440 Speaker 1: us as we all swish around the Milky Way, it 287 00:15:42,480 --> 00:15:45,640 Speaker 1: can perturb the orc cloud and send comets falling in 288 00:15:45,680 --> 00:15:47,960 Speaker 1: towards the center of the Solar system, right or steal them, 289 00:15:48,400 --> 00:15:51,960 Speaker 1: possibly steal them, or steal them absolutely, and we'll talk 290 00:15:51,960 --> 00:15:53,960 Speaker 1: about where these came from. It's not clear that all 291 00:15:53,960 --> 00:15:57,720 Speaker 1: of them actually came from our Solar system. And I 292 00:15:57,720 --> 00:16:00,880 Speaker 1: guess the thing is that we've never actually seen the cloud, right, Like, 293 00:16:00,920 --> 00:16:03,320 Speaker 1: we don't have pictures of it or even like radar 294 00:16:03,360 --> 00:16:05,960 Speaker 1: of it or evidence of it. That's right. It's so 295 00:16:06,080 --> 00:16:08,880 Speaker 1: far out there that it's still theoretical. There have been 296 00:16:08,960 --> 00:16:11,720 Speaker 1: some glimpses of one or two objects that people debate 297 00:16:12,040 --> 00:16:15,520 Speaker 1: might be like part of the Inner Inner Inner or cloud. 298 00:16:15,840 --> 00:16:19,280 Speaker 1: But these things are really small and really really far away, 299 00:16:19,320 --> 00:16:22,560 Speaker 1: Like it's hard to see Pluto, right, and Pluto is 300 00:16:22,640 --> 00:16:26,240 Speaker 1: really close compared to these things, and nothing that we 301 00:16:26,360 --> 00:16:29,120 Speaker 1: have out there in the Solar System has gotten anywhere 302 00:16:29,160 --> 00:16:31,400 Speaker 1: close to them, Like the thing that we have sent 303 00:16:31,600 --> 00:16:34,760 Speaker 1: out into space, that's the furthest object the humans have 304 00:16:34,920 --> 00:16:39,680 Speaker 1: ever built, that's Voyager one. The fastest human spaceship ever. Right, 305 00:16:40,200 --> 00:16:42,160 Speaker 1: that thing won't get to the beginning of the Orc 306 00:16:42,200 --> 00:16:46,160 Speaker 1: Cloud for another three hundred years. Well, Daniel, I don't 307 00:16:46,160 --> 00:16:49,280 Speaker 1: know if I believe in this thing or not, but 308 00:16:49,360 --> 00:16:51,800 Speaker 1: let's get into how we know it's actually there and 309 00:16:52,080 --> 00:16:55,760 Speaker 1: why we think it's important for our origin as a 310 00:16:55,960 --> 00:16:59,000 Speaker 1: planet and as a human species. But first, let's take 311 00:16:59,000 --> 00:17:14,440 Speaker 1: a quick break. All right, we're talking about the or Cloud, 312 00:17:14,880 --> 00:17:17,720 Speaker 1: which is uh. I guess Daniel, you would describe it 313 00:17:17,760 --> 00:17:22,879 Speaker 1: as like a giant shell of city size snowballs floating 314 00:17:22,920 --> 00:17:26,800 Speaker 1: out hundreds of light years away from the Sun. That's right, 315 00:17:27,000 --> 00:17:30,359 Speaker 1: And snowballs makes it sound quaint and fun and like 316 00:17:30,520 --> 00:17:32,199 Speaker 1: if you get hit by one, you can just go 317 00:17:32,320 --> 00:17:34,800 Speaker 1: inside and warm up with a cup of hot cocoa. Right, 318 00:17:35,119 --> 00:17:38,160 Speaker 1: But these things are massive ice balls, and if one 319 00:17:38,160 --> 00:17:40,920 Speaker 1: of them hit the Earth, we might be toasted. So 320 00:17:40,960 --> 00:17:43,320 Speaker 1: we'll talk about the danger these things later on, but 321 00:17:43,480 --> 00:17:45,440 Speaker 1: I want to make sure people are aware that these 322 00:17:45,440 --> 00:17:48,920 Speaker 1: are basically massive space bullets waiting to hit the Earth. 323 00:17:48,960 --> 00:17:50,800 Speaker 1: It's like a real snowball. If they pack enough ice 324 00:17:50,840 --> 00:17:53,160 Speaker 1: into that slush ball, it can really hurt. Yeah, alright, 325 00:17:53,200 --> 00:17:55,240 Speaker 1: so how do we know that it's actually there. Then 326 00:17:55,280 --> 00:17:57,560 Speaker 1: what makes us think that there is this giant cloud 327 00:17:57,600 --> 00:18:00,520 Speaker 1: of snowballs in space? Well, it comes um sort of 328 00:18:00,520 --> 00:18:03,320 Speaker 1: a paradox. In the last hundred years, we've established that 329 00:18:03,359 --> 00:18:06,240 Speaker 1: there are lots of comets, but the Solar system is 330 00:18:06,280 --> 00:18:08,840 Speaker 1: not very young, and so people have been wondering, like, 331 00:18:08,960 --> 00:18:12,000 Speaker 1: where do all these comets come from? Because comets are 332 00:18:12,000 --> 00:18:15,120 Speaker 1: not stable. Like, once a comet starts falling in towards 333 00:18:15,119 --> 00:18:17,760 Speaker 1: the Sun, it loses a lot of its mass as 334 00:18:17,760 --> 00:18:20,719 Speaker 1: the Sun boils it away. So a comet can't like 335 00:18:21,080 --> 00:18:24,000 Speaker 1: zip around the Sun for billions of years. It only 336 00:18:24,040 --> 00:18:26,880 Speaker 1: gets like, you know, fifty or a hundred, maybe two 337 00:18:27,000 --> 00:18:30,320 Speaker 1: hundred times around before it gets boiled away. Right, So 338 00:18:30,720 --> 00:18:33,040 Speaker 1: if that's the case, if comets don't last very long, 339 00:18:33,280 --> 00:18:36,399 Speaker 1: why are we still seeing commets? Like you lived in Arizona, 340 00:18:36,480 --> 00:18:38,360 Speaker 1: and every once in a while somebody throws a snowball 341 00:18:38,400 --> 00:18:41,040 Speaker 1: at your house, You're like, this is recent, Like somebody 342 00:18:41,119 --> 00:18:44,080 Speaker 1: just made this. Yeah, Or you know, if you're walking 343 00:18:44,080 --> 00:18:46,399 Speaker 1: around your neighborhood and everybody's eating ice cream, you're like, 344 00:18:46,520 --> 00:18:48,600 Speaker 1: where's the ice cream? Chuck? It must have just come by. 345 00:18:49,240 --> 00:18:51,600 Speaker 1: And so exactly, they thought there must be some sort 346 00:18:51,600 --> 00:18:55,120 Speaker 1: of source of these things. The other clue was that 347 00:18:55,160 --> 00:18:58,480 Speaker 1: there's sort of two types of comets. There are short 348 00:18:58,520 --> 00:19:01,240 Speaker 1: period comets. Com is to have an orbit around the 349 00:19:01,240 --> 00:19:04,200 Speaker 1: Sun that's like less than ten a U, and these 350 00:19:04,200 --> 00:19:06,439 Speaker 1: are mostly aligned with the Solar System. It seems like 351 00:19:06,440 --> 00:19:09,600 Speaker 1: they're like basically Solar System objects, just blobs of ice 352 00:19:09,960 --> 00:19:12,399 Speaker 1: somewhere in the outer reaches of the Solar System. But 353 00:19:12,480 --> 00:19:14,920 Speaker 1: then there's a second group of commets. They're called long 354 00:19:15,119 --> 00:19:18,040 Speaker 1: period comets. These are ones that have an orbit that's 355 00:19:18,080 --> 00:19:21,000 Speaker 1: like a thousand a U or more, and they take 356 00:19:21,040 --> 00:19:23,480 Speaker 1: a long time to go around the Sun, and they 357 00:19:23,600 --> 00:19:26,800 Speaker 1: don't follow the plane of the Solar system. So these 358 00:19:26,840 --> 00:19:28,960 Speaker 1: were really the mystery. They're like, where are these long 359 00:19:29,080 --> 00:19:32,520 Speaker 1: period comets coming from? They couldn't explain it. They shouldn't 360 00:19:32,560 --> 00:19:36,120 Speaker 1: stick around. And so to explain where the new ones 361 00:19:36,200 --> 00:19:38,919 Speaker 1: were coming from, they said, maybe there's a huge blob 362 00:19:38,960 --> 00:19:41,760 Speaker 1: of them somewhere out there beyond where we can see. Oh, 363 00:19:41,800 --> 00:19:44,600 Speaker 1: I see, you're saying these long period comments. They're sort 364 00:19:44,600 --> 00:19:46,960 Speaker 1: of coming out of left field. Doesn't look like they're 365 00:19:46,960 --> 00:19:48,879 Speaker 1: hanging out with us, or have been hanging out with 366 00:19:48,920 --> 00:19:52,000 Speaker 1: us for a long time. It's like they're coming from 367 00:19:52,080 --> 00:19:55,280 Speaker 1: somewhere else. Yeah, because they can't last for very long. Like, 368 00:19:55,359 --> 00:19:57,760 Speaker 1: once you see a comet, you're seeing it in the 369 00:19:57,880 --> 00:20:00,360 Speaker 1: end of its life cycle. It could have been out 370 00:20:00,400 --> 00:20:02,760 Speaker 1: happily for billions of years deep out there in the 371 00:20:02,760 --> 00:20:05,080 Speaker 1: Solar System. But once you see it, that means it's 372 00:20:05,119 --> 00:20:07,800 Speaker 1: falling towards the Sun and it's going to get boiled 373 00:20:07,840 --> 00:20:10,160 Speaker 1: away as it goes around the Sun, and it can't 374 00:20:10,160 --> 00:20:13,240 Speaker 1: survive for very long. And even if it does make 375 00:20:13,280 --> 00:20:15,560 Speaker 1: it a hundred or two hundred orbits, it's got a 376 00:20:15,640 --> 00:20:18,399 Speaker 1: high chance of getting kicked out of the Solar System 377 00:20:18,440 --> 00:20:21,560 Speaker 1: being perturbed by the gravity of one of the outer planets. 378 00:20:21,600 --> 00:20:24,040 Speaker 1: So once you see a comet, it means it's in 379 00:20:24,119 --> 00:20:26,639 Speaker 1: its last chapter of its life in the Solar System. 380 00:20:26,760 --> 00:20:29,320 Speaker 1: So we're still seeing comets four and a half billion 381 00:20:29,440 --> 00:20:31,679 Speaker 1: years into the story of the Solar System. There has 382 00:20:31,760 --> 00:20:34,320 Speaker 1: to be some fresh resupply every once in a while. 383 00:20:34,520 --> 00:20:36,440 Speaker 1: I guess if you're seeing a comment, that means it's 384 00:20:36,440 --> 00:20:38,920 Speaker 1: getting hit by the rays of the Sun, which is 385 00:20:38,960 --> 00:20:42,440 Speaker 1: probably melting it. It's definitely melting it, and that's where 386 00:20:42,440 --> 00:20:44,720 Speaker 1: the comets tail is. Right. People like to imagine the 387 00:20:44,720 --> 00:20:47,920 Speaker 1: commets tails like little action lines in a cartoon that 388 00:20:48,000 --> 00:20:50,680 Speaker 1: show you where it's moving. But the commets tail is 389 00:20:50,720 --> 00:20:54,080 Speaker 1: not actually pointed away from the direction of the comets motion. 390 00:20:54,560 --> 00:20:57,480 Speaker 1: It's pointed away from the sun because the tail comes 391 00:20:57,520 --> 00:21:01,840 Speaker 1: from the sun boiling away all the stuff on the comet. Yeah, 392 00:21:02,000 --> 00:21:04,720 Speaker 1: that's the signature tale of of comets. That's what it is. 393 00:21:04,880 --> 00:21:07,320 Speaker 1: It's not really a tail. It's more like a haircut. 394 00:21:07,480 --> 00:21:12,159 Speaker 1: Is that what you're saying, Yeah, precisely. And comets can 395 00:21:12,160 --> 00:21:15,080 Speaker 1: actually have multiple tales. They can have tales going in 396 00:21:15,119 --> 00:21:18,080 Speaker 1: different directions based on like the stuff that's in there 397 00:21:18,119 --> 00:21:21,160 Speaker 1: that's good and getting boiled away different compositions. So it's 398 00:21:21,160 --> 00:21:24,399 Speaker 1: pretty fascinating look at the tales of comets. It's pretty awesome. Okay. 399 00:21:24,400 --> 00:21:28,000 Speaker 1: So then someone named Yon Ord in the fifties said, hey, 400 00:21:28,000 --> 00:21:31,760 Speaker 1: maybe all of these weird long period comets are coming 401 00:21:32,000 --> 00:21:35,080 Speaker 1: from a very specific place. And so he came up 402 00:21:35,119 --> 00:21:37,320 Speaker 1: with this idea of the Ord cloud. Yeah, and he 403 00:21:37,359 --> 00:21:39,520 Speaker 1: looked at the orbits of these comets and he said, 404 00:21:39,520 --> 00:21:42,160 Speaker 1: how far out does it have to be to generate 405 00:21:42,240 --> 00:21:45,720 Speaker 1: comets with this length or but these long period comets, 406 00:21:46,240 --> 00:21:48,080 Speaker 1: And so that's how he estimated. He made a very 407 00:21:48,200 --> 00:21:50,800 Speaker 1: rough estimate for you know, how far away should be. 408 00:21:51,040 --> 00:21:54,160 Speaker 1: And since then we have much better data, better telescopes. 409 00:21:54,280 --> 00:21:57,320 Speaker 1: We can see the orbit of these comets much more clearly. 410 00:21:57,400 --> 00:21:59,920 Speaker 1: We have more telescopes, we have hubble and so be 411 00:22:00,040 --> 00:22:02,119 Speaker 1: can track all this stuff, and we have better estimates 412 00:22:02,119 --> 00:22:05,280 Speaker 1: for what's out there and how big it is. But 413 00:22:05,400 --> 00:22:08,199 Speaker 1: the basic idea came from this guy, yawned Ort in 414 00:22:08,320 --> 00:22:10,800 Speaker 1: nineteen fifty. And you know, it's pretty awesome to get 415 00:22:10,840 --> 00:22:13,280 Speaker 1: to put your name on the biggest thing in the 416 00:22:13,320 --> 00:22:16,080 Speaker 1: Solar system, Like this thing just dwarfs the rest of 417 00:22:16,080 --> 00:22:18,320 Speaker 1: the Solar system. Did he call it that the the 418 00:22:18,480 --> 00:22:20,840 Speaker 1: ord cloud or was it named after him? That's a 419 00:22:20,880 --> 00:22:23,800 Speaker 1: great question. I should read his original paper to see 420 00:22:23,840 --> 00:22:25,399 Speaker 1: if he put his own name on it or if 421 00:22:25,440 --> 00:22:27,639 Speaker 1: he was humble. Yeah, when he called the cloud of 422 00:22:27,720 --> 00:22:31,920 Speaker 1: Testimal and let somebody said that's a ridiculous name. We'll 423 00:22:31,960 --> 00:22:34,320 Speaker 1: go with orc. Yeah. And it's fascinating and it's cool 424 00:22:34,400 --> 00:22:36,720 Speaker 1: because it answers a question, right, It tells you, oh, 425 00:22:36,800 --> 00:22:39,159 Speaker 1: that must be where these comets are coming from. But 426 00:22:39,280 --> 00:22:41,639 Speaker 1: like everything in science, when you answer a question, it 427 00:22:41,840 --> 00:22:44,760 Speaker 1: opens up more questions, like all right, Well, where did 428 00:22:44,800 --> 00:22:47,200 Speaker 1: this ort cloud come from? Why is it there? Why 429 00:22:47,240 --> 00:22:50,240 Speaker 1: aren't they just closer into the rest of the Solar System. 430 00:22:50,280 --> 00:22:52,840 Speaker 1: And that's an active area of research right now. So 431 00:22:52,880 --> 00:22:55,760 Speaker 1: we actually haven't seen this cloud. We're just sort of 432 00:22:55,800 --> 00:22:59,640 Speaker 1: tracking where comets come from, and we think they come 433 00:22:59,680 --> 00:23:02,439 Speaker 1: from the cloud. Yeah, we have not seen this. We 434 00:23:02,520 --> 00:23:04,760 Speaker 1: don't have telescopes that are powerful enough to spot it, 435 00:23:05,040 --> 00:23:08,200 Speaker 1: none of our probes are anywhere near it. But it's 436 00:23:08,200 --> 00:23:10,919 Speaker 1: sort of the best explanation and we have for the 437 00:23:11,000 --> 00:23:14,359 Speaker 1: source of comets. So it's pretty well accepted in the 438 00:23:14,400 --> 00:23:18,520 Speaker 1: astronomical community that it exists. Like we always like to 439 00:23:18,560 --> 00:23:22,040 Speaker 1: see direct evidence of something before we conclude that it exists, 440 00:23:22,080 --> 00:23:25,159 Speaker 1: like there was evidence for Pluto before we spotted it 441 00:23:25,200 --> 00:23:28,080 Speaker 1: in a telescope. But you don't really claim discovery of 442 00:23:28,119 --> 00:23:31,240 Speaker 1: it until you actually see it, right, It's like finding 443 00:23:31,240 --> 00:23:33,960 Speaker 1: the body in a murder mystery. But sometimes it's the 444 00:23:34,000 --> 00:23:36,000 Speaker 1: best you can do for a while, so we can 445 00:23:36,000 --> 00:23:39,159 Speaker 1: talk later about like plans people have for how to 446 00:23:39,280 --> 00:23:41,560 Speaker 1: spot the Orc cloud and to study it, but for 447 00:23:41,680 --> 00:23:43,920 Speaker 1: now we have no direct evidence of it. I guess 448 00:23:43,960 --> 00:23:45,880 Speaker 1: it's not a thick enough cloud that it like makes 449 00:23:45,880 --> 00:23:48,760 Speaker 1: your view hazy, or you can see some of the 450 00:23:48,880 --> 00:23:52,280 Speaker 1: like the light getting filtered through it. It's not that thick, No, 451 00:23:52,480 --> 00:23:54,719 Speaker 1: it's not that thick. These things are very small and 452 00:23:54,840 --> 00:23:57,359 Speaker 1: very far away, so thick is definitely not how you 453 00:23:57,440 --> 00:24:02,600 Speaker 1: describe it. There's enormous that empty spaces between every object 454 00:24:02,680 --> 00:24:05,320 Speaker 1: in the orc cloud. Even though there are trillions and 455 00:24:05,400 --> 00:24:09,760 Speaker 1: trillions of objects. The space we're talking about is incredibly vast, Right, 456 00:24:10,040 --> 00:24:13,200 Speaker 1: We're talking about a sphere that's basically a light year 457 00:24:13,280 --> 00:24:16,159 Speaker 1: in radius, and so there's a lot of space in 458 00:24:16,200 --> 00:24:20,000 Speaker 1: there to distribute the trillion objects and still have lots 459 00:24:20,040 --> 00:24:21,960 Speaker 1: of room in between them. All Right, Well, I guess, 460 00:24:21,960 --> 00:24:23,600 Speaker 1: like you said, a big question is where did this 461 00:24:23,800 --> 00:24:26,280 Speaker 1: orc cloud come from? Like why is there all this 462 00:24:26,400 --> 00:24:29,639 Speaker 1: water deposited in one spot out there in the Solar system? 463 00:24:29,800 --> 00:24:32,040 Speaker 1: Beyond the Solar system. Well, as usual, we have a 464 00:24:32,040 --> 00:24:34,640 Speaker 1: few theories. We have sort of like the most boring 465 00:24:34,720 --> 00:24:37,960 Speaker 1: theory and then the most exciting theory, and the most 466 00:24:37,960 --> 00:24:40,320 Speaker 1: boring theory is sort of a story of the formation 467 00:24:40,400 --> 00:24:43,280 Speaker 1: of our Solar system. Like we start from a big 468 00:24:43,320 --> 00:24:46,719 Speaker 1: cloud of molecular gas and dust and stuff that collapses 469 00:24:47,080 --> 00:24:49,200 Speaker 1: and you get the Sun and you have a disc 470 00:24:49,240 --> 00:24:51,960 Speaker 1: of stuff that has too much angular momentum to collapse 471 00:24:52,000 --> 00:24:54,840 Speaker 1: into the Sun, so it spins around the Sun without 472 00:24:54,880 --> 00:24:59,040 Speaker 1: forming part of the star. And that's the protoplanetary disc, right. 473 00:24:59,280 --> 00:25:01,520 Speaker 1: And there you have of ice and gas and dust 474 00:25:01,760 --> 00:25:04,960 Speaker 1: and all kinds of stuff that starts to form planets 475 00:25:04,960 --> 00:25:07,679 Speaker 1: and clump together and form all sorts of stuff. The 476 00:25:07,720 --> 00:25:11,320 Speaker 1: idea is that not everything clumps together to form a planet, 477 00:25:11,359 --> 00:25:14,680 Speaker 1: like you have asteroids for example, of smaller things. Gravity 478 00:25:14,720 --> 00:25:18,880 Speaker 1: doesn't succeed in clumping everything together. But you do get 479 00:25:19,000 --> 00:25:22,480 Speaker 1: big gas giants out there, like Neptune and Urineus and 480 00:25:22,560 --> 00:25:25,359 Speaker 1: Saturn and Jupiter. They start to be sort of like 481 00:25:25,520 --> 00:25:29,320 Speaker 1: heavyweights of their own gravitationally, and they can perturb the 482 00:25:29,359 --> 00:25:31,760 Speaker 1: other stuff. And so there was a bit of a 483 00:25:31,880 --> 00:25:35,520 Speaker 1: dance in the early Solar System as these big planets 484 00:25:35,520 --> 00:25:38,399 Speaker 1: we're finding their place, and as they move around, they 485 00:25:38,440 --> 00:25:41,399 Speaker 1: affected everything else. So the short version of the story 486 00:25:41,440 --> 00:25:43,640 Speaker 1: is that we think that they were essentially tossed out 487 00:25:43,680 --> 00:25:46,560 Speaker 1: of the Solar System by some of these gas giants 488 00:25:46,600 --> 00:25:48,959 Speaker 1: as they were being born. These planets sort of like 489 00:25:49,200 --> 00:25:52,200 Speaker 1: muscled their way around the craziness of the Solar System. Yeah, 490 00:25:52,200 --> 00:25:54,480 Speaker 1: and one of the definitions of planets, if you believe 491 00:25:54,520 --> 00:25:58,080 Speaker 1: in you know, silly astronomical categories, is that it's cleared 492 00:25:58,119 --> 00:26:00,679 Speaker 1: its own path around the Sun. And so that's just 493 00:26:00,720 --> 00:26:02,879 Speaker 1: sort of like the job of growing up and being 494 00:26:02,960 --> 00:26:04,920 Speaker 1: a modern planet is that you have to like toss 495 00:26:05,000 --> 00:26:07,359 Speaker 1: the little bits out of the way, or you know, 496 00:26:07,440 --> 00:26:09,840 Speaker 1: slave them and make them into your moons. But in 497 00:26:09,880 --> 00:26:12,560 Speaker 1: this case, most of the stuff we think was tossed 498 00:26:12,560 --> 00:26:15,320 Speaker 1: out sort of in the early days of the Solar 499 00:26:15,320 --> 00:26:18,200 Speaker 1: System formation. And it also it had a reverse effect. 500 00:26:18,280 --> 00:26:21,199 Speaker 1: Remember gravity is always two directions. So we think that 501 00:26:21,280 --> 00:26:23,760 Speaker 1: one of the reasons that Neptune is as far out 502 00:26:23,840 --> 00:26:26,640 Speaker 1: as it is is that it got tugged out by 503 00:26:26,720 --> 00:26:29,880 Speaker 1: these objects as they were leaving the Solar System. I guess. 504 00:26:29,920 --> 00:26:32,320 Speaker 1: One question is if a planet is kind of plowing 505 00:26:32,359 --> 00:26:35,280 Speaker 1: through and sending things out into space, wouldn't it send 506 00:26:35,280 --> 00:26:38,520 Speaker 1: all kinds of things like asteroids and rocks and gas. 507 00:26:38,600 --> 00:26:43,560 Speaker 1: How did all this ice come together so purely, I guess, 508 00:26:43,560 --> 00:26:45,280 Speaker 1: And like, you know, why isn't it a mix of 509 00:26:45,280 --> 00:26:47,800 Speaker 1: all other things? Yeah, that's a great question. It is 510 00:26:47,880 --> 00:26:50,679 Speaker 1: mostly a mix, right, These things are not pure water. 511 00:26:50,880 --> 00:26:52,639 Speaker 1: It's like you go out there and you find these 512 00:26:52,680 --> 00:26:55,880 Speaker 1: pristine cubes of ice that you're ready to chisel out 513 00:26:55,920 --> 00:26:59,199 Speaker 1: and put onto your space cocktails. These things are dirty. 514 00:26:59,320 --> 00:27:02,040 Speaker 1: It's definitely still rocks in there. But remember that a 515 00:27:02,200 --> 00:27:04,919 Speaker 1: large fraction of the stuff in the outer Solar system 516 00:27:05,280 --> 00:27:08,040 Speaker 1: is ice, like you call uranus and neptune. They are 517 00:27:08,080 --> 00:27:11,119 Speaker 1: called ice giants, and so it's something of a matter 518 00:27:11,200 --> 00:27:14,359 Speaker 1: of how these chemicals are distributed through the solar system, 519 00:27:14,440 --> 00:27:17,480 Speaker 1: like where water ends up and ends up freezing and 520 00:27:17,520 --> 00:27:20,119 Speaker 1: gathering together. But a lot of the stuff in the 521 00:27:20,160 --> 00:27:23,080 Speaker 1: outer Solar system, and non significant fraction of all the 522 00:27:23,119 --> 00:27:26,800 Speaker 1: mass in the outer Solar system is water. I guess 523 00:27:26,840 --> 00:27:29,720 Speaker 1: out there most of it is ice and liquid, because 524 00:27:29,760 --> 00:27:32,120 Speaker 1: if it was closer, it would evaporate and maybe blow 525 00:27:32,119 --> 00:27:35,679 Speaker 1: out exactly. Some complicated arguments about where stuff in the 526 00:27:35,760 --> 00:27:38,959 Speaker 1: solar system collapses and what falls in and what doesn't. 527 00:27:39,119 --> 00:27:40,720 Speaker 1: But you end up with a lot of ice in 528 00:27:40,760 --> 00:27:44,120 Speaker 1: the outer Solar system. But these things are not pure water. Again, 529 00:27:44,160 --> 00:27:47,720 Speaker 1: they're definitely bits of rock. I would not recommend drinking 530 00:27:47,840 --> 00:27:51,000 Speaker 1: an or object if you found one, unless you like rocks, 531 00:27:52,040 --> 00:27:54,600 Speaker 1: unless they like your cocktails dirty. I guess they're dirty 532 00:27:54,600 --> 00:27:57,959 Speaker 1: snowballs all right, So that's one theory about how it forms, 533 00:27:58,000 --> 00:28:00,679 Speaker 1: just like you know, byproduct of the dynamics of the 534 00:28:00,720 --> 00:28:03,400 Speaker 1: solar system. What are the more interesting theories? The more 535 00:28:03,440 --> 00:28:07,159 Speaker 1: interesting theories are the interstellar theories. One idea is that 536 00:28:07,200 --> 00:28:10,480 Speaker 1: our son, when it formed, wasn't on its own. But 537 00:28:10,760 --> 00:28:13,639 Speaker 1: you know, we've discovered barely recently that a lot of 538 00:28:13,680 --> 00:28:16,359 Speaker 1: stars it was a twin. Yes, we're born as twins. 539 00:28:16,400 --> 00:28:20,160 Speaker 1: That binary star systems are much more common than we imagined. 540 00:28:20,600 --> 00:28:22,240 Speaker 1: So it could have been that our son had a 541 00:28:22,280 --> 00:28:26,040 Speaker 1: twin and that this collapsing cloud of stuff formed two 542 00:28:26,080 --> 00:28:28,639 Speaker 1: stars instead of one. But then these two sort of 543 00:28:28,720 --> 00:28:33,000 Speaker 1: drifted apart, as you know siblings sometimes do, and there's 544 00:28:33,000 --> 00:28:35,359 Speaker 1: a lot of material exchanged, and that gives you an 545 00:28:35,400 --> 00:28:39,360 Speaker 1: opportunity to sort of pull material further away from the 546 00:28:39,400 --> 00:28:42,360 Speaker 1: Sun because you have this big, heavy object, the other star, 547 00:28:42,760 --> 00:28:46,120 Speaker 1: tugging on your solar system. What so, what happened to 548 00:28:46,160 --> 00:28:49,000 Speaker 1: this other star, sister star. It's the subject of a 549 00:28:49,040 --> 00:28:51,320 Speaker 1: Netflix documentary, you know, where they're going to reunite the 550 00:28:51,360 --> 00:28:54,040 Speaker 1: stars for a dramatic conclusion at the end of the universe, 551 00:28:54,600 --> 00:28:59,800 Speaker 1: or a hit podcast mini series. That's right, not true crime, 552 00:28:59,840 --> 00:29:02,920 Speaker 1: but true physics. No, we don't know. It's just hypothetical. 553 00:29:02,960 --> 00:29:05,720 Speaker 1: We don't know that the Sun had a twin star 554 00:29:05,840 --> 00:29:08,640 Speaker 1: at its birth. It's just an idea. But if it did, 555 00:29:08,960 --> 00:29:11,200 Speaker 1: it could have been pulled off and gone in any direction. 556 00:29:11,360 --> 00:29:13,680 Speaker 1: It's been a long time, it's been billions of years, 557 00:29:13,960 --> 00:29:16,120 Speaker 1: and so it's hard to trace. It's not like the 558 00:29:16,160 --> 00:29:19,920 Speaker 1: nearest star is necessarily a category for our lost twin. 559 00:29:20,280 --> 00:29:22,480 Speaker 1: This thing would have been moving for a long time. 560 00:29:22,520 --> 00:29:24,520 Speaker 1: It could be anywhere at this point. And so the 561 00:29:24,560 --> 00:29:27,720 Speaker 1: idea is that the sister star pulled some things from 562 00:29:27,760 --> 00:29:30,080 Speaker 1: the Sun and then left it out there and where 563 00:29:30,120 --> 00:29:32,320 Speaker 1: the orc tod would be. Yeah, just like we were 564 00:29:32,360 --> 00:29:35,160 Speaker 1: talking about the gas giants tossing stuff out of the 565 00:29:35,160 --> 00:29:38,080 Speaker 1: Solar system, Now you have a much bigger object, a 566 00:29:38,120 --> 00:29:41,760 Speaker 1: heavier object, another star even further out. It's going to 567 00:29:41,840 --> 00:29:44,160 Speaker 1: tug out some of these stuff in our solar system 568 00:29:44,400 --> 00:29:46,920 Speaker 1: to have a very large radius. And then as the 569 00:29:46,960 --> 00:29:49,720 Speaker 1: to sort of separate. I'm imagining, like you know, sell 570 00:29:49,840 --> 00:29:52,720 Speaker 1: mitoses here two stars are pulling apart from each other 571 00:29:52,920 --> 00:29:55,040 Speaker 1: and it's sort of like threads in between them, and 572 00:29:55,080 --> 00:29:57,560 Speaker 1: then as they get far enough away, they stop affecting 573 00:29:57,560 --> 00:30:01,200 Speaker 1: each other gravitationally and things settle into place. But you 574 00:30:01,240 --> 00:30:03,960 Speaker 1: have stuff out at a pretty far radius because the 575 00:30:04,000 --> 00:30:07,160 Speaker 1: gravitational pull of the other star interesting. So it was 576 00:30:07,200 --> 00:30:10,320 Speaker 1: like the leftover from the divorce or something I just 577 00:30:10,360 --> 00:30:13,240 Speaker 1: got dropped there in the middle of space. That's right, 578 00:30:13,560 --> 00:30:17,200 Speaker 1: the poor abandoned objects in the stellar o c so 579 00:30:17,280 --> 00:30:22,960 Speaker 1: many seems appropriate. All right, let's get into our last 580 00:30:23,040 --> 00:30:26,440 Speaker 1: theory about where this orc cloud came from and what 581 00:30:26,600 --> 00:30:29,320 Speaker 1: it all means. The first let's take another quick break. 582 00:30:41,800 --> 00:30:45,920 Speaker 1: All right, Daniel, there's a giant cloud of snowballs out 583 00:30:46,000 --> 00:30:49,280 Speaker 1: in space about three light years away from the Sun, 584 00:30:50,000 --> 00:30:51,800 Speaker 1: and we think that's where comments come from. But the 585 00:30:51,880 --> 00:30:54,400 Speaker 1: question is where did this cloud come from? And so 586 00:30:54,480 --> 00:30:57,400 Speaker 1: you have one more theory for us about that, and 587 00:30:57,560 --> 00:31:01,720 Speaker 1: I'm going to guess it involves eight It involves alien stars, 588 00:31:02,080 --> 00:31:04,360 Speaker 1: though we don't know if there are aliens enough living 589 00:31:04,400 --> 00:31:06,880 Speaker 1: around those stars. The problem is that if you do 590 00:31:06,920 --> 00:31:09,880 Speaker 1: the calculations, and you have your theory of the Solar 591 00:31:09,920 --> 00:31:12,880 Speaker 1: system and you predict how many things there should be 592 00:31:12,960 --> 00:31:15,160 Speaker 1: in the or cloud, you get a number that's way 593 00:31:15,160 --> 00:31:18,320 Speaker 1: too small. You get a number like six billion objects. 594 00:31:18,600 --> 00:31:21,040 Speaker 1: But we know the number is much much bigger than that. 595 00:31:21,560 --> 00:31:23,480 Speaker 1: So the idea is like, well, where do these things 596 00:31:23,560 --> 00:31:26,080 Speaker 1: come from? So wait, how do we know how big 597 00:31:26,120 --> 00:31:28,000 Speaker 1: it should be? If we don't, we've never seen it 598 00:31:28,040 --> 00:31:30,160 Speaker 1: and it's all theoretical. Is it just from like the 599 00:31:30,240 --> 00:31:33,640 Speaker 1: frequency of comments that we get exactly to explain the 600 00:31:33,720 --> 00:31:36,440 Speaker 1: number of comments that we see, and they're radius and stuff, 601 00:31:36,600 --> 00:31:38,960 Speaker 1: there should be a certain number of objects in the 602 00:31:39,120 --> 00:31:42,240 Speaker 1: Orc cloud, otherwise we would see fewer and fewer comments. 603 00:31:42,280 --> 00:31:44,320 Speaker 1: But if we try to predict how many things are 604 00:31:44,360 --> 00:31:47,000 Speaker 1: in the Orc cloud from sort of first principles formation, 605 00:31:47,040 --> 00:31:49,200 Speaker 1: like how many things should have been tossed out there 606 00:31:49,200 --> 00:31:52,160 Speaker 1: by Neptune and Saturn Uranus, then we get a much 607 00:31:52,200 --> 00:31:55,120 Speaker 1: smaller number. So there's a discrepancy there. We know there 608 00:31:55,160 --> 00:31:57,880 Speaker 1: are objects out there, we can't explain how they got there. 609 00:31:58,560 --> 00:32:01,640 Speaker 1: So one idea is as well, when our star was forming, 610 00:32:01,960 --> 00:32:04,840 Speaker 1: what was going on nearby? We talked about how maybe 611 00:32:04,840 --> 00:32:07,320 Speaker 1: there was a sister star formed with us. But another 612 00:32:07,440 --> 00:32:11,760 Speaker 1: idea is that maybe our stellar cloud that collapsed was 613 00:32:11,920 --> 00:32:15,760 Speaker 1: near some other objects and it stole some material from 614 00:32:15,800 --> 00:32:19,000 Speaker 1: those objects. That basically the Orc cloud is like a 615 00:32:19,040 --> 00:32:22,280 Speaker 1: lot of stuff from other solar systems that was stolen 616 00:32:22,320 --> 00:32:28,160 Speaker 1: by our sun when it formed. What it could be stolen? Good? Yeah, 617 00:32:28,320 --> 00:32:31,120 Speaker 1: the water we're drinking could have been stolen from another 618 00:32:31,160 --> 00:32:33,200 Speaker 1: solar system. Is that what you're saying? You should feel 619 00:32:33,200 --> 00:32:36,120 Speaker 1: guilty every time you have a drink. It's elicit. But 620 00:32:36,160 --> 00:32:39,600 Speaker 1: it could basically be all a muamua, right, Remember Mumua 621 00:32:39,760 --> 00:32:43,560 Speaker 1: was this interstellar comment, this frozen object that passed through 622 00:32:43,560 --> 00:32:47,800 Speaker 1: our solar system coming from some other solar system. And 623 00:32:47,880 --> 00:32:50,480 Speaker 1: it could be that the Orc Cloud is basically just 624 00:32:50,560 --> 00:32:52,200 Speaker 1: a bunch of these. Oh I see, is that a 625 00:32:52,280 --> 00:32:55,080 Speaker 1: theory that Oma came from the Orc Cloud? No, mum 626 00:32:55,280 --> 00:32:57,560 Speaker 1: It definitely did not come from the Orc Cloud. Its 627 00:32:57,560 --> 00:33:00,080 Speaker 1: trajectory is totally inconsistent with that. We know that it 628 00:33:00,200 --> 00:33:03,080 Speaker 1: came from another solar system. But it could be think 629 00:33:03,080 --> 00:33:06,040 Speaker 1: the Orc Cloud is the product of stealing a bunch 630 00:33:06,040 --> 00:33:10,320 Speaker 1: of Omumua like objects much much earlier, a long time ago, 631 00:33:10,600 --> 00:33:13,920 Speaker 1: as our solar systems forming. So you know, possession is 632 00:33:14,000 --> 00:33:16,400 Speaker 1: nine tenths of the law. Then you know we've had 633 00:33:16,400 --> 00:33:19,480 Speaker 1: these for billions of years. They're basically ours now, but 634 00:33:19,680 --> 00:33:22,240 Speaker 1: there's a bit of original sin there and having stolen 635 00:33:22,240 --> 00:33:24,880 Speaker 1: them from another solar system a long time ago. Well, yeah, 636 00:33:24,920 --> 00:33:27,360 Speaker 1: I guess, because you know, I think the closest stars 637 00:33:27,360 --> 00:33:30,800 Speaker 1: to us our solar system are about what is it 638 00:33:30,880 --> 00:33:33,800 Speaker 1: like five light years away, right, yeah, three and a 639 00:33:33,840 --> 00:33:36,479 Speaker 1: half light years away to proximates Centauri. Yeah, so this 640 00:33:36,600 --> 00:33:39,320 Speaker 1: orc cloud is about where those other stars are. Yeah, 641 00:33:39,360 --> 00:33:41,800 Speaker 1: it's the right order of magnitude, right, it's that big. 642 00:33:42,080 --> 00:33:44,320 Speaker 1: It's so big that it gets you part way to 643 00:33:44,600 --> 00:33:48,480 Speaker 1: other stars. And those other stars probably have their own clouds, 644 00:33:48,520 --> 00:33:50,440 Speaker 1: and these stars tugging each other, and one of the 645 00:33:50,440 --> 00:33:53,720 Speaker 1: ways to perturb our or cloud is to have other 646 00:33:53,720 --> 00:33:56,640 Speaker 1: stars come nearby and give it like a little gravitational tug, 647 00:33:56,920 --> 00:34:00,200 Speaker 1: which results in comets falling towards the Earth. Also, an 648 00:34:00,200 --> 00:34:02,760 Speaker 1: orac cloud is not necessarily like a good thing. We 649 00:34:02,800 --> 00:34:05,200 Speaker 1: talked about stealing this, but like it's a bunch of 650 00:34:05,240 --> 00:34:08,279 Speaker 1: bullets hanging over our head where at the bottom of 651 00:34:08,320 --> 00:34:11,080 Speaker 1: this gravity, well, any of them roll down, they could 652 00:34:11,120 --> 00:34:13,840 Speaker 1: totally wipe us out, like deadly hail or something. You 653 00:34:13,840 --> 00:34:16,120 Speaker 1: don't You don't necessarily want that, it won't create a 654 00:34:16,160 --> 00:34:18,840 Speaker 1: winter wonder lamp. You want it early on, so we 655 00:34:18,880 --> 00:34:21,120 Speaker 1: can give you oceans, but then you basically want to 656 00:34:21,200 --> 00:34:23,239 Speaker 1: give them away. To your neighbor, so you don't have 657 00:34:23,280 --> 00:34:25,799 Speaker 1: them anymore. Wow. Alright, so it is kind of like 658 00:34:25,800 --> 00:34:30,800 Speaker 1: a giant interplanetary snowball fight almost or tug of war. Yeah, 659 00:34:31,040 --> 00:34:33,839 Speaker 1: and that's where we think most commets come from. And 660 00:34:33,920 --> 00:34:35,759 Speaker 1: you know, every time you see a comet that's come 661 00:34:35,800 --> 00:34:38,080 Speaker 1: from the outer Solar System, it's been out there for 662 00:34:38,200 --> 00:34:42,120 Speaker 1: billions of years, happily orbiting, not being close to anybody, 663 00:34:42,280 --> 00:34:45,480 Speaker 1: being an introvert. And now it's screaming towards the center 664 00:34:45,480 --> 00:34:48,439 Speaker 1: of the Solar System, maybe hitting a planet, maybe hitting 665 00:34:48,480 --> 00:34:51,680 Speaker 1: the Sun, maybe just whipping around and going back out right. 666 00:34:51,880 --> 00:34:54,440 Speaker 1: It's kind of dangerous. It's actually quite dangerous. You know. 667 00:34:54,480 --> 00:34:58,200 Speaker 1: People talk about asteroids hitting the Earth and worrying about 668 00:34:58,239 --> 00:35:00,800 Speaker 1: big rocks and planet killers and all kinds of stuff, 669 00:35:01,040 --> 00:35:04,080 Speaker 1: But the truth is NASA has most of those figured out. 670 00:35:04,120 --> 00:35:07,120 Speaker 1: Like most of the asteroids, the things in our Solar System, 671 00:35:07,400 --> 00:35:10,400 Speaker 1: we could see them because they're pretty close, certainly anything 672 00:35:10,440 --> 00:35:13,160 Speaker 1: that's big enough to cause us any danger. And NASA 673 00:35:13,160 --> 00:35:17,000 Speaker 1: has a great team of planetary protectors tracking these things 674 00:35:17,000 --> 00:35:19,120 Speaker 1: and predicting where they're gonna be and letting us know 675 00:35:19,160 --> 00:35:22,040 Speaker 1: if they're gonna be anywhere nearby, and often one of 676 00:35:22,080 --> 00:35:23,920 Speaker 1: them slips through and we don't see it until it 677 00:35:23,960 --> 00:35:26,920 Speaker 1: hits us. But that's because it's small. So a really 678 00:35:27,080 --> 00:35:30,319 Speaker 1: big object that would actually cause any damage. NASA is 679 00:35:30,360 --> 00:35:32,680 Speaker 1: pretty sure we're safe from those for a couple hundred 680 00:35:32,760 --> 00:35:34,880 Speaker 1: years because they're hanging out in the Solar System, so 681 00:35:34,880 --> 00:35:36,919 Speaker 1: we can kind of see them, but we can see them. 682 00:35:36,920 --> 00:35:39,120 Speaker 1: But if it's coming from outside the Solar System, then 683 00:35:39,120 --> 00:35:42,040 Speaker 1: it can surprise us. Yeah, if it comes from left field, 684 00:35:42,360 --> 00:35:44,799 Speaker 1: it could be a real surprise. These things could have 685 00:35:44,920 --> 00:35:48,239 Speaker 1: orbits that are hundreds or thousands of years, and so 686 00:35:48,480 --> 00:35:51,400 Speaker 1: the first time we see one might be the last 687 00:35:51,440 --> 00:35:54,560 Speaker 1: time we see one because it could be headed for Earth. 688 00:35:55,000 --> 00:35:57,360 Speaker 1: And so these things could fall into the Solar System 689 00:35:57,719 --> 00:36:00,760 Speaker 1: and smack right into a planet and you know, cause 690 00:36:00,800 --> 00:36:03,640 Speaker 1: a lot of destruction. Because they also they move really 691 00:36:03,719 --> 00:36:07,520 Speaker 1: really fast. They've been accelerating for a long time falling 692 00:36:07,520 --> 00:36:09,520 Speaker 1: in towards the Sun, and so they have a huge 693 00:36:09,520 --> 00:36:13,200 Speaker 1: amount of kinetic energy. This is not a gently tossed snowball. 694 00:36:13,480 --> 00:36:16,200 Speaker 1: This is like a rocket. It's like a rocket propelled 695 00:36:16,360 --> 00:36:19,200 Speaker 1: missile launched snowball. Yeah, you give like a really hard 696 00:36:19,200 --> 00:36:22,239 Speaker 1: block of ice to a major League pitcher and stand 697 00:36:22,320 --> 00:36:23,680 Speaker 1: right in front of the mess. He throws it at 698 00:36:23,680 --> 00:36:26,040 Speaker 1: your face. That's about how terrifying this is. Just like 699 00:36:26,120 --> 00:36:29,600 Speaker 1: when they threw those frozen turkeys at airplane to see 700 00:36:29,640 --> 00:36:32,400 Speaker 1: if the airplanes would break. Is that a real experiment 701 00:36:32,520 --> 00:36:35,399 Speaker 1: used to make that up? That's a real thing. They 702 00:36:35,480 --> 00:36:38,360 Speaker 1: shot frozen turkeys at an airplanes to see what would happen. 703 00:36:39,080 --> 00:36:41,440 Speaker 1: And it's happened before, right, Like our Solar system has 704 00:36:41,480 --> 00:36:44,680 Speaker 1: gone pelted by giant snowballs, and some of them even 705 00:36:44,800 --> 00:36:47,240 Speaker 1: hit some planets. Yeah, exactly. If you think, oh, that's 706 00:36:47,280 --> 00:36:49,880 Speaker 1: not likely to happen, or it might only happen every 707 00:36:49,920 --> 00:36:53,480 Speaker 1: thousand or million years, we don't know how often it happens, 708 00:36:53,480 --> 00:36:56,440 Speaker 1: but we do know that it happened recently. It was 709 00:36:56,480 --> 00:36:59,680 Speaker 1: in the nineties that a big comet hit Jupiter commt 710 00:37:00,160 --> 00:37:02,600 Speaker 1: Maker Levy. It broke up into a bunch of pieces 711 00:37:02,760 --> 00:37:06,240 Speaker 1: and each one pelted Jupiter, and even after it broke 712 00:37:06,320 --> 00:37:09,960 Speaker 1: up and made fireballs that were larger than Earth when 713 00:37:10,000 --> 00:37:13,240 Speaker 1: each one hit. So these are very dramatic planetary events, 714 00:37:13,320 --> 00:37:15,080 Speaker 1: not the kind of thing we want to have happened 715 00:37:15,080 --> 00:37:18,239 Speaker 1: to Earth. Yeah, that would be bad, It would be bad. 716 00:37:18,280 --> 00:37:20,600 Speaker 1: And now, Daniel, I have a note here in the 717 00:37:20,640 --> 00:37:22,920 Speaker 1: document you send me here, and I'm trying to figure 718 00:37:22,920 --> 00:37:29,560 Speaker 1: out it says also space centaurs, And that's it. What 719 00:37:29,640 --> 00:37:32,840 Speaker 1: does that even mean? Space centers are so much fun. 720 00:37:33,120 --> 00:37:35,440 Speaker 1: I decided to make it a whole other episode for 721 00:37:35,480 --> 00:37:37,719 Speaker 1: a few weeks from now. But there is this thing 722 00:37:37,880 --> 00:37:42,399 Speaker 1: in the Solar System called a space center. Seriously, it's 723 00:37:42,440 --> 00:37:46,280 Speaker 1: a thing. Scientists found the thing and called them space centers. 724 00:37:46,320 --> 00:37:49,480 Speaker 1: But they're not like you might imagine, maybe like you know, 725 00:37:49,960 --> 00:37:52,919 Speaker 1: asteroids that happened to look like the fusion between man 726 00:37:52,960 --> 00:37:56,120 Speaker 1: and horse. No, they're just the name that you give 727 00:37:56,320 --> 00:38:00,360 Speaker 1: small objects between Jupiter and Neptune that sort of cross 728 00:38:00,440 --> 00:38:03,320 Speaker 1: back and forth between the orbits of these gas giants, 729 00:38:03,320 --> 00:38:05,879 Speaker 1: sort of like transitional objects. So they're like we could 730 00:38:05,880 --> 00:38:09,560 Speaker 1: call them space unicorns or space griffins. That would be 731 00:38:09,560 --> 00:38:12,719 Speaker 1: too crazy, but we'll go with space centers. I don't 732 00:38:12,719 --> 00:38:14,520 Speaker 1: know what kind of bananas they were smoking the day 733 00:38:14,640 --> 00:38:16,839 Speaker 1: they came up with that name, but it did tickle 734 00:38:16,920 --> 00:38:19,680 Speaker 1: my sense of humor. But they think that maybe space 735 00:38:19,719 --> 00:38:23,200 Speaker 1: centers also have come from the orc cloud. They've essentially 736 00:38:23,239 --> 00:38:27,240 Speaker 1: fallen in and then into these more stable orbits somewhere 737 00:38:27,239 --> 00:38:29,839 Speaker 1: in the outer solar systems thing. Well, then I vote 738 00:38:29,880 --> 00:38:34,480 Speaker 1: we rename comments to space unicorns. I second your motion, 739 00:38:34,640 --> 00:38:39,160 Speaker 1: but I don't think we have any jurisdiction here. All right, Well, 740 00:38:39,200 --> 00:38:41,680 Speaker 1: it sounds like comments are pretty cool. They might be 741 00:38:41,680 --> 00:38:45,200 Speaker 1: coming from the Orc cloud, this theoretical cloud out there 742 00:38:45,200 --> 00:38:47,680 Speaker 1: in space which gave us water, which is a good thing, 743 00:38:47,719 --> 00:38:50,400 Speaker 1: but which may kill us in the future. And so 744 00:38:50,520 --> 00:38:52,920 Speaker 1: we're we're studying this cloud. Now we're studying comments more. 745 00:38:53,000 --> 00:38:54,960 Speaker 1: What are we doing about it? Well, we're doing everything 746 00:38:55,000 --> 00:38:58,160 Speaker 1: we can. It's pretty hard to spot these things right there, 747 00:38:58,200 --> 00:39:01,520 Speaker 1: so small, they're so far away. People have one really 748 00:39:01,560 --> 00:39:05,000 Speaker 1: fun idea for how to visualize these things, and essentially 749 00:39:05,000 --> 00:39:09,080 Speaker 1: it's to look for star eclipses. Like if we are 750 00:39:09,160 --> 00:39:12,839 Speaker 1: surrounded by this huge cloud of these little objects there 751 00:39:12,880 --> 00:39:15,760 Speaker 1: essentially black, they're so far away they don't reflect enough sunlight, 752 00:39:16,160 --> 00:39:20,680 Speaker 1: but occasionally they should pass in front of stars, causing 753 00:39:20,680 --> 00:39:24,320 Speaker 1: these little transitions where the star basically blinks out momentarily. 754 00:39:25,040 --> 00:39:27,760 Speaker 1: So you can look at all the stars and watch 755 00:39:27,800 --> 00:39:30,480 Speaker 1: them and wait to see if you see one of 756 00:39:30,480 --> 00:39:33,560 Speaker 1: these eclipses, and if you do, then you can use 757 00:39:33,560 --> 00:39:36,520 Speaker 1: that to measure like how many things there are out there, 758 00:39:36,560 --> 00:39:38,920 Speaker 1: but based on the rate at which you see these things, 759 00:39:38,960 --> 00:39:40,959 Speaker 1: And if you don't, then you can set a limit 760 00:39:41,000 --> 00:39:43,080 Speaker 1: and say, well, there can't be that many, otherwise I 761 00:39:43,080 --> 00:39:45,960 Speaker 1: would have seen them. You're looking at Like how the 762 00:39:46,080 --> 00:39:49,080 Speaker 1: stars are twinkling, Yeah, because they might be twinkling because 763 00:39:49,080 --> 00:39:52,200 Speaker 1: of a giant comment heading towards us, Yeah, or just 764 00:39:52,320 --> 00:39:56,640 Speaker 1: a giant, silent, frozen comment passing between us and that star. 765 00:39:57,239 --> 00:39:58,960 Speaker 1: And you know it has to line up just right. 766 00:39:59,000 --> 00:40:01,120 Speaker 1: You have to draw a line between the Earth and 767 00:40:01,160 --> 00:40:04,760 Speaker 1: that star super far away, and then the orc cloud 768 00:40:04,800 --> 00:40:07,960 Speaker 1: object has to basically break that line in order for 769 00:40:08,040 --> 00:40:11,120 Speaker 1: there to be this eclipse. So it's not that likely, 770 00:40:11,320 --> 00:40:13,120 Speaker 1: but there are a lot of stars out there and 771 00:40:13,160 --> 00:40:15,600 Speaker 1: maybe a lot of orc cloud objects, so if you 772 00:40:15,600 --> 00:40:18,080 Speaker 1: get enough telescope time, you might be able to spot it. 773 00:40:18,160 --> 00:40:20,360 Speaker 1: And unicorns are pretty magical, so you never know what 774 00:40:20,360 --> 00:40:23,440 Speaker 1: they're gonna do. What if they're all turned out to 775 00:40:23,440 --> 00:40:27,200 Speaker 1: be rainbow colored, that would be amazing. And it could 776 00:40:27,280 --> 00:40:30,759 Speaker 1: also be that if we pass nearby another star, that 777 00:40:30,760 --> 00:40:34,080 Speaker 1: that star could like pass through our or cloud, causing 778 00:40:34,160 --> 00:40:37,040 Speaker 1: like a new bombardment of comets, and that would be 779 00:40:37,080 --> 00:40:39,120 Speaker 1: sort of a confirmation because we'd see a lot of 780 00:40:39,160 --> 00:40:42,160 Speaker 1: these things rushing towards the inner Solar system. Well, clearly 781 00:40:42,160 --> 00:40:45,000 Speaker 1: we need to build like an ice Ford Daniel around 782 00:40:45,040 --> 00:40:48,759 Speaker 1: the Earth. That um, yeah, I think it's called Neptune. 783 00:40:49,840 --> 00:40:53,040 Speaker 1: That's an ice giant, and hopefully it captures these things 784 00:40:53,160 --> 00:40:55,680 Speaker 1: as they come into the inner Solar system. You know, 785 00:40:55,719 --> 00:40:58,640 Speaker 1: we actually do have the gas giants to thank for 786 00:40:58,719 --> 00:41:01,120 Speaker 1: protecting us from a lot of these things. They tend 787 00:41:01,120 --> 00:41:02,759 Speaker 1: to pull them in and they also tend to clean 788 00:41:02,800 --> 00:41:06,120 Speaker 1: them up. So without those big planets out there protecting 789 00:41:06,239 --> 00:41:10,200 Speaker 1: us from the o C bullies throwing snowballs, we would 790 00:41:10,200 --> 00:41:11,560 Speaker 1: have had a rougher time of it. And then, to 791 00:41:11,640 --> 00:41:14,080 Speaker 1: be ironic, if there was a like a giant comment 792 00:41:14,120 --> 00:41:16,480 Speaker 1: heading towards us, but then at the last minute Pluto 793 00:41:16,560 --> 00:41:20,040 Speaker 1: gets in the way and blocks it. That sounds like 794 00:41:20,080 --> 00:41:22,200 Speaker 1: the plot of our movie. That sounds like a good 795 00:41:22,239 --> 00:41:28,360 Speaker 1: slow motion scene at the end and flat and everyone's like, oh, Pluto, 796 00:41:29,280 --> 00:41:31,160 Speaker 1: we took you for granted, but now you see it 797 00:41:31,320 --> 00:41:35,040 Speaker 1: is all it's too late, but now we value your contribution, 798 00:41:35,640 --> 00:41:38,000 Speaker 1: all right. Well, the next time you look out into 799 00:41:38,040 --> 00:41:40,759 Speaker 1: the night, Skuy, we hope you think about what's out 800 00:41:40,800 --> 00:41:44,320 Speaker 1: there and what could possibly be out there, and also 801 00:41:44,360 --> 00:41:46,960 Speaker 1: think of ice unicorns floating out there in space. And 802 00:41:47,000 --> 00:41:49,399 Speaker 1: remember that there's a lot of things out there that 803 00:41:49,440 --> 00:41:52,800 Speaker 1: we still don't understand, sources of mystery, sources of wonder, 804 00:41:52,880 --> 00:41:56,000 Speaker 1: and sources of danger. So we better get on it 805 00:41:56,040 --> 00:41:58,759 Speaker 1: and figure this stuff out before it wipes us out, 806 00:41:59,000 --> 00:42:01,600 Speaker 1: or it might be too late. We're ready or not. 807 00:42:01,840 --> 00:42:03,480 Speaker 1: All right, Well, we hope you enjoyed that. Thanks for 808 00:42:03,560 --> 00:42:14,600 Speaker 1: joining us, See you next time. Thanks for listening, and 809 00:42:14,640 --> 00:42:17,360 Speaker 1: remember that Daniel and Jorge Explain the Universe is a 810 00:42:17,400 --> 00:42:20,840 Speaker 1: production of I Heart Radio or more podcast For my 811 00:42:20,960 --> 00:42:24,560 Speaker 1: heart Radio, visit the I heart Radio app, Apple Podcasts, 812 00:42:24,680 --> 00:42:27,000 Speaker 1: or wherever you listen to your favorite shows.