1 00:00:04,600 --> 00:00:09,400 This is John G B with all of us, trampled, most of us think of 2 00:00:09,400 --> 00:00:13,600 the solar system as the sun, plus a set of planets in orbit 3 00:00:13,600 --> 00:00:16,800 around it. But that leaves out the asteroid 4 00:00:16,800 --> 00:00:21,400 belt a region lying between the orbits of Mars and Jupiter which 5 00:00:21,400 --> 00:00:25,100 contains billions and billions of asteroids ranging in size, 6 00:00:25,100 --> 00:00:30,000 from Pebbles to dwarf planets. It turns out that asteroids 7 00:00:30,000 --> 00:00:33,200 contain, Tell us a great deal about the origin of the Earth in 8 00:00:33,200 --> 00:00:36,500 many ways more than we can learn by looking at the other planets 9 00:00:36,500 --> 00:00:37,800 such as Venus. And Mars. 10 00:00:37,800 --> 00:00:42,700 Sarah Russell is Professor of planetary, sciences and leader 11 00:00:42,700 --> 00:00:46,300 of the planetary materials group at the Natural History Museum in 12 00:00:46,300 --> 00:00:50,500 London using asteroids as snapshots of the early solar 13 00:00:50,500 --> 00:00:54,500 system, how research seeks to unravel, how the solar system 14 00:00:54,500 --> 00:00:59,000 formed and answer questions such as how the Earth got its water 15 00:00:59,000 --> 00:01:00,800 and organic. Ariel's. 16 00:01:01,300 --> 00:01:03,500 She even has an asteroid named after. 17 00:01:04,400 --> 00:01:07,000 So Russell. Welcome to geology, B. 18 00:01:07,000 --> 00:01:08,200 Thank you very much for inviting. 19 00:01:08,200 --> 00:01:10,900 Me Oliver, what are the asteroids? 20 00:01:10,900 --> 00:01:15,400 So, an asteroid is basically a rocky body that is in orbit 21 00:01:15,400 --> 00:01:20,000 around our sun. And we can differentiate it from 22 00:01:20,000 --> 00:01:22,700 comets, which are the other small bodies that go around the 23 00:01:22,700 --> 00:01:25,500 Sun and that comets tend to be much more. 24 00:01:25,500 --> 00:01:29,400 I see full of volatile materials and they originated further out 25 00:01:29,400 --> 00:01:31,100 in the outermost reaches of the solar system. 26 00:01:31,100 --> 00:01:35,100 But have eccentric orbits, so they come As the inner solar 27 00:01:35,100 --> 00:01:38,900 system where we can see them. And in contrast, asteroids are 28 00:01:38,900 --> 00:01:42,000 made almost entirely of Rocky materials, that means 29 00:01:42,000 --> 00:01:46,200 silica-based minerals and metals and things like that. 30 00:01:46,800 --> 00:01:49,500 And we can distinguish both asteroids and comets from 31 00:01:49,500 --> 00:01:52,800 meteorites, which is any natural, extraterrestrial 32 00:01:52,800 --> 00:01:55,600 material that lands on the surface of the Earth. 33 00:01:56,400 --> 00:01:59,900 So some of the things that land on the earth, then I'm not 34 00:01:59,900 --> 00:02:02,800 asteroids at all. Know me traits can be anything. 35 00:02:02,800 --> 00:02:06,400 So, actually, the vast majority, See our pieces of asteroids, 36 00:02:06,400 --> 00:02:09,900 which is brilliant for those of us who are interested in 37 00:02:09,900 --> 00:02:12,600 asteroids, but also some meteorites are pieces of the 38 00:02:12,600 --> 00:02:15,400 Moon and some are pieces of Mars. 39 00:02:15,700 --> 00:02:17,900 And some we just don't know what they are. 40 00:02:18,000 --> 00:02:21,600 So so, so there's a whole variety of stuff that falls from 41 00:02:21,600 --> 00:02:24,300 space for us to try to figure out. 42 00:02:25,000 --> 00:02:29,800 So why are asteroids concentrated just in a region 43 00:02:29,800 --> 00:02:32,200 between the orbits of Mars and Jupiter? 44 00:02:32,400 --> 00:02:34,200 Yeah, and we think the answer to that goes. 45 00:02:34,400 --> 00:02:36,100 Right back to the beginning of the solar system. 46 00:02:36,100 --> 00:02:40,200 So the solar system formed from a disk of dust and gas that was 47 00:02:40,200 --> 00:02:45,200 orbiting around the evolving young son, and these bits of 48 00:02:45,200 --> 00:02:48,600 dust gradually accreted together to make larger and larger 49 00:02:48,600 --> 00:02:51,300 Pebbles, and then Boulders and larger and larger objects, until 50 00:02:51,300 --> 00:02:55,500 they eventually formed the planets that we see today and 51 00:02:55,500 --> 00:02:57,700 Jupiter is the biggest planet in our solar system. 52 00:02:57,700 --> 00:03:02,600 It from very early on, and Jupiter was so massive that it 53 00:03:02,800 --> 00:03:06,000 caused all sorts of forces. Has in this area between Mars 54 00:03:06,000 --> 00:03:09,500 and Jupiter, that kept forcing these bodies apart and cause 55 00:03:09,500 --> 00:03:11,600 them to be quite energetic and have lots of impacts on. 56 00:03:11,600 --> 00:03:14,500 That means that no Planet could form in that region. 57 00:03:14,500 --> 00:03:18,300 So now we just see this debris of this material from the early 58 00:03:18,300 --> 00:03:21,000 solar system, which is now our asteroid belt. 59 00:03:21,800 --> 00:03:24,200 As I mentioned in the introduction, there are billions 60 00:03:24,200 --> 00:03:29,400 of asteroids and if that concentrated are they like the 61 00:03:29,400 --> 00:03:33,200 artist Impressions often show them as pretty close packed in 62 00:03:33,200 --> 00:03:36,800 space. No, so if you see a sci-fi film 63 00:03:36,800 --> 00:03:39,400 when they go through an asteroid belt, you can see these pictures 64 00:03:39,400 --> 00:03:41,500 right? Of loads of Boulders all over 65 00:03:41,500 --> 00:03:44,900 the place crashing into the astronaut spaceship, but 66 00:03:44,900 --> 00:03:47,900 actually, it's not like that. So you would get one Boulder and 67 00:03:47,900 --> 00:03:50,500 then the next one will be thousands and thousands of miles 68 00:03:50,500 --> 00:03:52,100 away. There's a lot of space out there 69 00:03:52,100 --> 00:03:55,300 so even though there's a lot of asteroids, they're not all that 70 00:03:55,300 --> 00:03:58,800 densely packed and all of the spacecraft that have gone to the 71 00:03:58,800 --> 00:04:02,600 outer solar system like New Horizons and Voyager, they've 72 00:04:02,600 --> 00:04:04,200 all gone through the asteroid belt. 73 00:04:04,300 --> 00:04:06,000 Out with absolutely no problem at all. 74 00:04:06,000 --> 00:04:08,600 So that shows they're actually not very densely packed at all. 75 00:04:09,100 --> 00:04:11,300 There are several different types of asteroid. 76 00:04:11,800 --> 00:04:14,100 Yeah, there are several different types of asteroids, so 77 00:04:14,100 --> 00:04:18,000 we can investigate this from Earth, looking at the spectral 78 00:04:18,000 --> 00:04:20,100 features of the asteroids, I presume. 79 00:04:20,100 --> 00:04:23,000 These are features that appear in the Spectra of the near 80 00:04:23,000 --> 00:04:26,500 infrared and visible light, reflected, by the asteroids. 81 00:04:26,700 --> 00:04:31,500 Yes, I'm from that kind of work. We know that there's an amazing 82 00:04:31,500 --> 00:04:33,500 compositional diversity of asteroids. 83 00:04:33,500 --> 00:04:36,500 So, I'm asteroids are very rich in carbon. 84 00:04:36,900 --> 00:04:41,600 Some seem to be Rocky, some seem to be made of Basalt much like 85 00:04:41,600 --> 00:04:44,500 the surface of the Earth. Some are made of metal. 86 00:04:44,700 --> 00:04:48,200 We know the largest asteroid in the asteroid belt Series has got 87 00:04:48,200 --> 00:04:52,600 an ice volcano on it. So there's an amazing diversity 88 00:04:52,600 --> 00:04:55,900 of different compositions across the asteroid belt. 89 00:04:55,900 --> 00:04:58,100 And yet it's one of the fun things about studying asteroids 90 00:04:58,100 --> 00:05:02,100 is actually they're much more diverse in composition than the 91 00:05:02,200 --> 00:05:05,000 inner planets for example. So It accounts for this 92 00:05:05,000 --> 00:05:09,800 diversity, we don't know in detail, but it could be that in 93 00:05:09,800 --> 00:05:13,600 the earliest times in the solar system, the giant planets 94 00:05:13,600 --> 00:05:17,700 Jupiter and Saturn were actually migrated they moved in and out 95 00:05:17,800 --> 00:05:21,300 of the protoplanetary disk and that could have disrupted, small 96 00:05:21,300 --> 00:05:22,700 bodies that were forming another region. 97 00:05:22,700 --> 00:05:25,900 So it could cause for example, bodies that were rich and 98 00:05:25,900 --> 00:05:28,700 volatiles that formed in the outer solar system to be thrown 99 00:05:28,700 --> 00:05:32,300 into the inner solar system. So we end up with this mismatch 100 00:05:32,600 --> 00:05:34,100 over loads and loads of different body. 101 00:05:34,300 --> 00:05:38,100 That's actually formed different parts of the solar system and 102 00:05:38,100 --> 00:05:41,800 also, depending on how big they are, they have very different 103 00:05:41,800 --> 00:05:43,600 histories. So a lot of asteroids seem to 104 00:05:43,608 --> 00:05:45,700 have not changed at all since the beginning of the solar 105 00:05:45,700 --> 00:05:49,100 system, but others have undergone some geology and so 106 00:05:49,100 --> 00:05:51,200 they've changed since they first formed. 107 00:05:51,500 --> 00:05:55,900 How can asteroids actually then tell us anything about the Earth 108 00:05:56,300 --> 00:06:00,300 in lots of ways Oliver? So in some ways, the Earth has 109 00:06:00,300 --> 00:06:03,200 kind of forgotten about its early history because on Earth 110 00:06:03,200 --> 00:06:06,100 is so much joy. Elegy going on, everything's 111 00:06:06,100 --> 00:06:10,500 been mushed up and mixed and melted, but many of these 112 00:06:10,500 --> 00:06:13,600 asteroids have not changed since the beginning of the solar 113 00:06:13,600 --> 00:06:15,500 system. And so they tell us something 114 00:06:15,900 --> 00:06:19,200 about the primordial material that all the planets, including 115 00:06:19,200 --> 00:06:23,200 the Earth came from. So the majority of asteroids and 116 00:06:23,200 --> 00:06:25,300 meteorites, that we have to study on Earth. 117 00:06:25,300 --> 00:06:29,200 Have we look at them in detail? They've never melted and they're 118 00:06:29,200 --> 00:06:32,300 made up of particles of different sizes or mixed up 119 00:06:32,300 --> 00:06:35,800 together and these particles. Some of them formed at very high 120 00:06:35,800 --> 00:06:39,600 temperatures, and some of them formed at low temperatures. 121 00:06:39,600 --> 00:06:43,300 So, that's telling us that the solar system formed from this 122 00:06:43,600 --> 00:06:46,100 dust cloud, where there are lots of different environments and 123 00:06:46,100 --> 00:06:47,900 lots of different things got mixed up together. 124 00:06:48,200 --> 00:06:50,400 And this was probably the primordial material that made 125 00:06:50,400 --> 00:06:53,000 the Earth and looking at these asteroid or meteorites. 126 00:06:53,000 --> 00:06:56,200 We can learn how old the Earth is because we think they formed 127 00:06:56,200 --> 00:06:59,100 at the same time as the Earth and they can tell us that the 128 00:06:59,100 --> 00:07:01,800 Earth was about four and a half billion years old and we can 129 00:07:01,800 --> 00:07:07,300 even unpick the components and Look at how long these particles 130 00:07:07,400 --> 00:07:12,700 existed in the protoplanetary dusty disc and we get these ages 131 00:07:12,800 --> 00:07:17,700 from radiometric dating methods. Most commonly using the decay of 132 00:07:17,700 --> 00:07:21,000 uranium to lead, just as we do for the Earth rocks. 133 00:07:21,600 --> 00:07:25,600 So, you said that among the different kinds of asteroid. 134 00:07:25,600 --> 00:07:28,800 There are the kinds that are Rocky and the kinds that are 135 00:07:28,800 --> 00:07:33,500 more metallic and the ones that seem to be more metallic. 136 00:07:33,600 --> 00:07:36,300 What To the rocky stuff. Did they just never have it to 137 00:07:36,308 --> 00:07:38,300 begin with or did it vaporize when they're? 138 00:07:38,300 --> 00:07:40,900 Yes, as I said. So most asteroids, we think 139 00:07:40,900 --> 00:07:45,000 never melted at all and they just made up this primordial 140 00:07:45,000 --> 00:07:48,500 stuff that solar system was made of, but there are some asteroids 141 00:07:48,500 --> 00:07:50,500 that seem to be made mostly of metal. 142 00:07:50,500 --> 00:07:52,900 And we see these in our meteorite collections, we have 143 00:07:52,900 --> 00:07:55,500 meteorites that are made of iron nickel alloy. 144 00:07:55,800 --> 00:08:00,500 And we think that these formed from asteroids that became big 145 00:08:00,500 --> 00:08:02,800 enough and had enough heat in them that they melted. 146 00:08:02,800 --> 00:08:06,300 And when they melted the The iron in them, sank down to form 147 00:08:06,600 --> 00:08:10,200 a core and so they had a core of metal and then that was 148 00:08:10,200 --> 00:08:13,800 surrounded by igneous, Rocky material and actually an Army 149 00:08:13,800 --> 00:08:16,500 Track collections. We also have samples of this 150 00:08:16,500 --> 00:08:20,100 differentiated igneous, Rocky material that made up the 151 00:08:20,400 --> 00:08:22,500 mantle, or crust of these asteroids. 152 00:08:22,900 --> 00:08:26,100 But one, a kind of weird things in meteorite science is that we 153 00:08:26,100 --> 00:08:28,500 have basaltic meteorites, which would have been the crust of 154 00:08:28,500 --> 00:08:30,600 these asteroids. But we don't really have so much 155 00:08:30,600 --> 00:08:33,299 of the mantle material. And so we have this missing 156 00:08:34,200 --> 00:08:36,000 Mantle and we don't really know what happened to it. 157 00:08:36,000 --> 00:08:38,400 So it could have been. As you say that it was vaporized 158 00:08:38,400 --> 00:08:41,799 during impacts in the asteroid belt and we've just lost that 159 00:08:41,799 --> 00:08:45,100 record but the but the iron which caused are more resilient 160 00:08:45,100 --> 00:08:48,300 to impacts and so maybe they survive better. 161 00:08:48,500 --> 00:08:50,800 And so maybe that's why we see so many of these. 162 00:08:51,100 --> 00:08:55,400 But the iron-rich meteorites are interesting because they might 163 00:08:55,400 --> 00:08:57,200 provide an analog to the Earth's core. 164 00:08:57,200 --> 00:08:59,700 We know that the Earth has gone through this process of heating 165 00:08:59,700 --> 00:09:03,900 and melting and forming a metal core, but we can't access our 166 00:09:03,900 --> 00:09:06,500 own Nurse Corps to look at what the composition is, but we can 167 00:09:06,500 --> 00:09:09,400 use these iron meteorites of some kind of analogy to what 168 00:09:09,400 --> 00:09:11,500 might have happened during Earth's differentiation. 169 00:09:11,900 --> 00:09:13,800 That's interesting. So, the metallic ones like a 170 00:09:13,800 --> 00:09:16,300 naked core, that we know she look at. 171 00:09:16,500 --> 00:09:17,700 Yeah. Well, that's what we're 172 00:09:17,700 --> 00:09:18,800 thinking. Yeah, no. 173 00:09:18,800 --> 00:09:20,600 Actually, there's a space mission called psyche. 174 00:09:20,600 --> 00:09:24,300 That's going to visit one of these metal-rich asteroids, and 175 00:09:24,300 --> 00:09:27,500 that should provide some clues about their origin and see if 176 00:09:27,500 --> 00:09:30,100 that is the case. So, if the Earth was hot enough 177 00:09:30,100 --> 00:09:34,600 to melt metal and have it sink down to form, Cool. 178 00:09:35,300 --> 00:09:37,500 How did it get to be covered with water? 179 00:09:38,100 --> 00:09:42,100 Well, so we can also thank Asteroids for that because many 180 00:09:42,100 --> 00:09:47,200 asteroids contain writes, a lot of water and they contain a lot 181 00:09:47,200 --> 00:09:50,800 of organic material as well. And the Earth has been 182 00:09:50,800 --> 00:09:54,800 continuously bombarded with asteroid or meteorite since its 183 00:09:54,800 --> 00:09:58,400 formation and in the early stages of the solar system, the 184 00:09:58,400 --> 00:10:01,700 impact rate would have been even higher when the solar system was 185 00:10:01,700 --> 00:10:04,500 a more energetic and chaotic kind of place. 186 00:10:04,800 --> 00:10:08,500 And so after the Earth, had differentiated the water that's 187 00:10:08,500 --> 00:10:10,800 created. The Earth's oceans could have 188 00:10:10,800 --> 00:10:13,500 been brought there by meteorite impacts. 189 00:10:13,500 --> 00:10:15,200 That's a hell of a lot of meteorites. 190 00:10:16,000 --> 00:10:19,000 Well, I don't think it's, I mean, we look at the Earth from 191 00:10:19,000 --> 00:10:21,100 space and it looks like a watery planet, right? 192 00:10:21,100 --> 00:10:24,600 Because two-thirds of the Earth is covered in water and that 193 00:10:24,600 --> 00:10:27,900 water from a human perspective. These look like really deep 194 00:10:27,900 --> 00:10:29,300 oceans. But from a planetary 195 00:10:29,300 --> 00:10:33,300 perspective, this is a very, very thin skin on the surface of 196 00:10:33,300 --> 00:10:36,100 the planet. So there's not from a planetary 197 00:10:36,100 --> 00:10:39,000 bulk composition perspective. There's not that much water, 198 00:10:39,300 --> 00:10:41,900 whereas, meteorites can contain loads of water. 199 00:10:41,900 --> 00:10:45,400 So carbonaceous chondrites, which seemed to be the 200 00:10:45,400 --> 00:10:50,200 predominant flux of material for at least very tiny particles. 201 00:10:50,500 --> 00:10:55,000 They can contain up to 20% water in the form of clay minerals. 202 00:10:55,000 --> 00:10:58,000 So they contain these Clays that can trap water in their 203 00:10:58,000 --> 00:11:01,100 structure. And so they can actually deliver 204 00:11:01,300 --> 00:11:03,500 huge amounts of water to the Earth that way. 205 00:11:04,100 --> 00:11:08,100 We're actually in a very exciting time from an asteroid 206 00:11:08,200 --> 00:11:12,100 point of view because there are two missions currently underway 207 00:11:12,600 --> 00:11:16,500 to fetch samples from the surface of two different, 208 00:11:16,500 --> 00:11:20,500 asteroids, and return it to us. And you're a member of the 209 00:11:20,500 --> 00:11:23,000 science team for both of them. Yes. 210 00:11:23,000 --> 00:11:27,100 So the two currently in Flight missions, there's a Japanese one 211 00:11:27,100 --> 00:11:31,900 called Hayabusa 2 which has already collected a sample from 212 00:11:31,900 --> 00:11:35,700 its asteroid Raghu and It's on its way back to Earth. 213 00:11:35,700 --> 00:11:39,500 Now it's going to return to Earth in December 2020 and the 214 00:11:39,500 --> 00:11:43,100 other mission is a NASA mission called Osiris Rex, and that is 215 00:11:43,100 --> 00:11:46,700 currently in orbit around the asteroid bennu, and it's going 216 00:11:46,700 --> 00:11:52,400 to collect a sample next month in October 20 20, and then it's 217 00:11:52,400 --> 00:11:55,700 due back to Earth in 2023. How big are these? 218 00:11:55,700 --> 00:11:57,900 Asteroids, they're not very big at all. 219 00:11:57,900 --> 00:12:02,200 So Raghu, the target for Hayabusa 2 is about a kilometer 220 00:12:02,200 --> 00:12:05,500 across. And I knew the target for 221 00:12:05,500 --> 00:12:10,000 asaurus Rex is about 500 meters across, so it's kind of about 222 00:12:10,000 --> 00:12:12,900 the size of a skyscraper really. It's not very big in the grand 223 00:12:12,900 --> 00:12:16,000 scheme of things but that's what makes it really exciting because 224 00:12:16,000 --> 00:12:18,900 the smaller it is, the more likely it is to have this 225 00:12:18,900 --> 00:12:22,100 primordial material and not have too much geology of happened to 226 00:12:22,100 --> 00:12:24,400 it. So it's more likely to be a 227 00:12:24,400 --> 00:12:28,300 pristine sample of the early solar system and do these things 228 00:12:28,300 --> 00:12:33,300 have enough gravity to hold a space probe in orbit around 229 00:12:33,300 --> 00:12:36,500 them. Well, they, yeah, they only have 230 00:12:36,500 --> 00:12:40,900 a teeny, tiny fraction of the gravity of Earth because there's 231 00:12:40,900 --> 00:12:43,700 such tiny bodies, though, Cyrus Rex. 232 00:12:43,700 --> 00:12:48,400 For example, it is in orbit around been, oh, but to be in 233 00:12:48,400 --> 00:12:51,100 orbit around Benny, what has to be super super close. 234 00:12:51,100 --> 00:12:54,500 So it's only about a kilometer away from the center of the 235 00:12:54,900 --> 00:12:56,800 asteroid. So it's actually has the world 236 00:12:56,800 --> 00:13:01,700 record for being the closest orbiting satellite around a 237 00:13:01,700 --> 00:13:03,900 body. So it's an incredible feat. 238 00:13:04,000 --> 00:13:07,000 Out of the rocket scientists and the engineers to have actually 239 00:13:07,000 --> 00:13:11,100 managed to successfully, put the spacecraft in orbit around this 240 00:13:11,100 --> 00:13:13,500 sign Iraq. And then it's actually going to 241 00:13:13,508 --> 00:13:17,200 go down to the surface to scoop up a little bit. 242 00:13:17,400 --> 00:13:20,000 Yes. So this is the most dramatic 243 00:13:20,100 --> 00:13:23,700 moment of the mission perhaps. So it's going to go down to the 244 00:13:23,700 --> 00:13:27,000 surface and it has a kind of reverse vacuum cleaner. 245 00:13:27,000 --> 00:13:32,600 So blast of gas will be pointed at the surface of been 0 and 246 00:13:32,600 --> 00:13:36,700 that will disrupt the Rocks and fragments on the surface of the 247 00:13:36,700 --> 00:13:40,700 asteroid which will then get captured into the collection 248 00:13:40,800 --> 00:13:43,400 capsule and then hopefully brought back to Earth for us to 249 00:13:43,400 --> 00:13:46,500 take a look at. So what are we hoping to learn 250 00:13:46,500 --> 00:13:50,100 from these samples? That will be returned with great 251 00:13:50,100 --> 00:13:53,800 difficulty to Earth. Yes, I spent my career studying 252 00:13:53,900 --> 00:13:57,700 meteorites and mostly meteorites that come from asteroids. 253 00:13:58,000 --> 00:14:01,100 And these missions are like the dream for scientists like me 254 00:14:01,100 --> 00:14:03,900 because we love our meteorites, but the problem with me try, 255 00:14:04,000 --> 00:14:06,400 It's is that they fall on Earth. We don't really know where 256 00:14:06,400 --> 00:14:08,800 they've come from. We don't have a chance to do 257 00:14:08,800 --> 00:14:11,800 fieldwork like terrestrial just to. 258 00:14:11,800 --> 00:14:14,200 We can't choose that the samples that we get. 259 00:14:14,200 --> 00:14:16,200 We just get whatever's lands on Earth. 260 00:14:16,600 --> 00:14:22,100 But these missions are the chance for us to look at a 261 00:14:22,100 --> 00:14:26,200 sample of a primordial, asteroid or body. 262 00:14:26,200 --> 00:14:28,700 That we think came from the very earliest times in the solar 263 00:14:28,700 --> 00:14:31,500 system that will tell us about the origins of our solar system. 264 00:14:32,100 --> 00:14:36,100 And it will tell us that with the A global geological 265 00:14:36,100 --> 00:14:39,400 perspective of all the mapping, that's these missions have been 266 00:14:39,400 --> 00:14:42,400 doing at the same time. So it will really give us some 267 00:14:42,400 --> 00:14:45,900 geological and astronomical context of these samples which 268 00:14:45,900 --> 00:14:49,400 are so important to try to learn about their Origins. 269 00:14:49,500 --> 00:14:51,700 Will it be like this? So called Ground. 270 00:14:51,700 --> 00:14:55,700 Truth that we have with these Earth missions where we have 271 00:14:55,700 --> 00:14:58,200 lots of pictures of the Earth for it to be able to correlate 272 00:14:58,200 --> 00:15:00,100 the two. You actually have to go down to 273 00:15:00,100 --> 00:15:02,700 the bit that you're looking at and grab a bit of it. 274 00:15:02,700 --> 00:15:06,100 Is that going to enable you to? To link what we get back from 275 00:15:06,100 --> 00:15:09,900 bennu with some of the asteroid. So that in your collection and 276 00:15:09,900 --> 00:15:12,400 then you can just say oh well those definitely came from 277 00:15:12,400 --> 00:15:16,700 asteroids, absolutely. So the Hayabusa to Mission is 278 00:15:16,700 --> 00:15:19,100 actually that as you might expect from the name, it's the 279 00:15:19,100 --> 00:15:20,700 second. Asteroid return mission that the 280 00:15:20,700 --> 00:15:23,700 Japanese have done and the first asteroid return. 281 00:15:23,700 --> 00:15:27,600 Mission Hayabusa went to a type of asteroid called the S-Type 282 00:15:27,600 --> 00:15:32,000 asteroids that we'd always suspected were similar to a type 283 00:15:32,000 --> 00:15:33,900 of meat right in our collection called Ordinary chondrite. 284 00:15:34,000 --> 00:15:37,000 We didn't know for sure. And it was only when we had that 285 00:15:37,300 --> 00:15:39,600 sample return, that we could make that connection 286 00:15:40,200 --> 00:15:43,600 definitively and that then enables us to understand our 287 00:15:43,600 --> 00:15:45,500 meteorite collections much, much better. 288 00:15:45,500 --> 00:15:49,200 So, yeah, one of the important things about these missions is 289 00:15:49,200 --> 00:15:53,700 that they help us to understand. Not just me, try to look 290 00:15:53,700 --> 00:15:56,300 identical to these these Roxbury, they'll help us 291 00:15:56,300 --> 00:15:58,200 understand our whole meteorite collection. 292 00:15:58,500 --> 00:16:03,000 And the other thing, it will help us do is to understand the 293 00:16:03,000 --> 00:16:06,400 diversity of asteroids that we can observe from Earth because 294 00:16:06,400 --> 00:16:09,600 it will ground truth, our spectral data so that it will 295 00:16:09,900 --> 00:16:13,300 help us to have that one connection of. 296 00:16:13,300 --> 00:16:16,800 We have a sample on Earth and we can also see it in space that 297 00:16:16,800 --> 00:16:22,000 will help us to calibrate and looking at all of asteroids and 298 00:16:22,000 --> 00:16:23,600 small bodies in our solar system. 299 00:16:24,300 --> 00:16:28,200 How did we select been you out of all the thousands of 300 00:16:28,200 --> 00:16:30,700 asteroids? We could have picked one big 301 00:16:30,700 --> 00:16:33,900 reason that it was picked is because it's what we call. 302 00:16:34,000 --> 00:16:37,200 The c-type asteroid which we think contain organic material. 303 00:16:37,200 --> 00:16:41,800 And one of the main aims of the mission is to learn about 304 00:16:41,900 --> 00:16:46,100 Organics in the solar system are how they may have come to Earth 305 00:16:46,100 --> 00:16:50,100 and seeded life on Earth and tell us about our Origins as 306 00:16:50,100 --> 00:16:53,000 earthlings how we got our water and what it can tell us about 307 00:16:53,000 --> 00:16:56,200 the formation of the earth. So the type of asteroid was very 308 00:16:56,200 --> 00:16:57,600 important. And the other thing that was 309 00:16:57,600 --> 00:17:01,100 very important was where it was. So benno is a near-earth 310 00:17:01,100 --> 00:17:05,900 asteroid and so it's Not in the asteroid belt between Mars and 311 00:17:05,900 --> 00:17:07,900 Jupiter. It probably was once but it's 312 00:17:07,900 --> 00:17:11,400 been knocked out into an orbit. That's much closer to the 313 00:17:11,400 --> 00:17:14,000 Earth's orbit around the Sun so that makes it much more 314 00:17:14,000 --> 00:17:17,200 accessible and much easier for us to go there and Sample it 315 00:17:18,000 --> 00:17:21,200 there's something else that I think you mentioned to me when 316 00:17:21,200 --> 00:17:25,500 we were talking earlier that by studying the details of the 317 00:17:25,500 --> 00:17:30,000 Albedo that is the fraction of the incident radiation that is 318 00:17:30,000 --> 00:17:33,800 reflected by the surface of the asteroid we can tell in detail. 319 00:17:34,000 --> 00:17:37,600 Tell what its future orbit is going to be and we really care 320 00:17:37,600 --> 00:17:41,400 about that because it has a finite chance of colliding with 321 00:17:41,400 --> 00:17:43,300 the earth. Oh yes, of course. 322 00:17:43,300 --> 00:17:46,500 That's another important reason for looking at bennu and 323 00:17:46,600 --> 00:17:48,200 near-earth, asteroids in general. 324 00:17:48,200 --> 00:17:53,500 So we know on Earth that we do get hit by asteroids, sometimes 325 00:17:53,500 --> 00:17:57,100 their big asteroids and can do a huge amount of damage on Earth 326 00:17:57,100 --> 00:18:00,800 but we want to understand that risk as well as we can. 327 00:18:00,800 --> 00:18:04,900 And one of the ways that we can do that is to Study asteroids 328 00:18:04,900 --> 00:18:09,400 like bennu in details. So bennu is a potentially 329 00:18:09,500 --> 00:18:12,900 hazardous asteroids in that. It's got a tiny probability of 330 00:18:12,900 --> 00:18:16,400 hitting the Earth, in about 200 years time, but what we want to 331 00:18:16,400 --> 00:18:20,600 do is try to make our calculations about whether it's 332 00:18:20,600 --> 00:18:23,600 likely to hit or not a bit more precise. 333 00:18:23,600 --> 00:18:27,900 And we can do that by making very precise measurements of its 334 00:18:27,900 --> 00:18:31,200 lb do and the heterogeneity of the asteroid and so on and that 335 00:18:31,200 --> 00:18:33,700 will help us to understand what's called the yarkovsky 336 00:18:33,700 --> 00:18:36,200 effect. Switch has an effect on small 337 00:18:36,200 --> 00:18:40,000 bodies of solar radiation. Pushing them as a very, very 338 00:18:40,000 --> 00:18:43,100 gentle Force, but it's something that we need to understand to be 339 00:18:43,100 --> 00:18:47,500 able to have accurate models of how the orbits of these objects 340 00:18:47,500 --> 00:18:50,300 are going to evolve over the next centuries. 341 00:18:50,900 --> 00:18:56,300 This yarkovsky effect that you mentioned is to do with solo 342 00:18:56,300 --> 00:19:01,900 radiation pressure, which depends and turn on the Albedo, 343 00:19:01,900 --> 00:19:05,900 which is how much of the the incident solar radiation gets 344 00:19:05,900 --> 00:19:11,200 reflected and therefore how much it pushes on the asteroid and 345 00:19:11,200 --> 00:19:16,500 changes its orbit. So if bennu did wind up hitting 346 00:19:16,500 --> 00:19:20,300 the Earth in some catastrophe. Now, how would that compare with 347 00:19:20,300 --> 00:19:23,200 the asteroid that we think hit the earth? 348 00:19:23,200 --> 00:19:26,400 66 million years ago and caused the extinction of the dinosaurs 349 00:19:26,400 --> 00:19:29,400 and much of Life? Yeah, well, I was going to say, 350 00:19:29,400 --> 00:19:31,900 great thing about asteroids, but another interesting thing about 351 00:19:31,900 --> 00:19:37,100 asteroids is that You have this capacity to cause global 352 00:19:37,100 --> 00:19:39,000 destruction. And the last time that happened, 353 00:19:39,200 --> 00:19:43,800 of course, was about 66 million years ago, an asteroid impacted 354 00:19:43,900 --> 00:19:46,600 off the coast of Mexico in chicxulub. 355 00:19:46,800 --> 00:19:52,600 And we think this impact caused massive Devastation and mass 356 00:19:52,600 --> 00:19:56,600 extinctions of the dinosaurs and other animals, but then that led 357 00:19:56,600 --> 00:20:01,400 to the rise of the mammals and and eventually to humans. 358 00:20:01,400 --> 00:20:06,200 So these are catastrophic Vents do change the course of 359 00:20:06,200 --> 00:20:09,900 evolution but they can sometimes change them in potentially 360 00:20:09,900 --> 00:20:13,800 interesting ways. So we think an asteroid about a 361 00:20:13,800 --> 00:20:17,800 kilometer in size, that's about the size of Raghu if that hits 362 00:20:17,800 --> 00:20:21,200 the Earth that would cause global Devastation will have 363 00:20:21,200 --> 00:20:24,800 catastrophic Global effects. So that so that's the target of 364 00:20:24,800 --> 00:20:29,600 the very worst level of impact and we think such a globally 365 00:20:29,600 --> 00:20:32,600 destructive impact might happen about once. 366 00:20:32,600 --> 00:20:35,200 Every hundred And million years or so. 367 00:20:35,200 --> 00:20:38,400 So it's not something that's likely to happen on our watch 368 00:20:38,400 --> 00:20:43,300 but it can happen and it probably will happen over the 369 00:20:43,400 --> 00:20:46,200 four or five billion years that the Earth has got remaining to 370 00:20:46,400 --> 00:20:48,600 exist. So something that we're 371 00:20:48,600 --> 00:20:52,300 interested in mapping what near-earth, asteroids might be 372 00:20:52,300 --> 00:20:55,200 potentially hazardous and how hazardous they might be. 373 00:20:56,100 --> 00:21:00,100 So for my last question, I want to ask you if you had unlimited 374 00:21:00,100 --> 00:21:06,600 resources for your research, How would you use them, right? 375 00:21:06,600 --> 00:21:10,300 I love that question. So if I had unlimited resources, 376 00:21:10,300 --> 00:21:14,400 what I think I would love to do. I Love sample, return missions 377 00:21:14,400 --> 00:21:17,700 for all the reasons that we've talked about actually going into 378 00:21:17,700 --> 00:21:20,500 space and bring a sample back that we can study in the lab 379 00:21:20,900 --> 00:21:24,900 tells us so much about the origins and age and 380 00:21:24,900 --> 00:21:28,100 characteristics of this object. So it would have to be a 381 00:21:28,100 --> 00:21:30,500 mission, a sample return mission, that will bring stuff 382 00:21:30,500 --> 00:21:32,500 back to Earth for us to have in our collections. 383 00:21:32,600 --> 00:21:37,000 And the places that I would love to get a sample from these 384 00:21:37,200 --> 00:21:40,800 Interstellar Interlopers. So couple of years ago, the 385 00:21:40,800 --> 00:21:44,900 first Interstellar asteroid struck combat was observed 386 00:21:44,900 --> 00:21:48,200 coming into our solar system called omura so we don't know 387 00:21:48,200 --> 00:21:52,600 where it came from, it came into our solar system and then it 388 00:21:52,600 --> 00:21:55,800 disappeared off again. But having a sample of something 389 00:21:55,800 --> 00:21:57,900 that is from beyond our solar system. 390 00:21:57,900 --> 00:22:01,500 Could tell us so much about our place in the Galaxy, whether 391 00:22:01,500 --> 00:22:05,200 there's anything Peculiar about our solar system that led to the 392 00:22:05,200 --> 00:22:09,500 evolution of life and ultimately us or whether we're very common 393 00:22:09,500 --> 00:22:13,400 and that is the one thing that we could do so much science on 394 00:22:13,400 --> 00:22:17,500 to learn about, not only our solar system, but the universe 395 00:22:17,500 --> 00:22:20,100 beyond us. So Russell. 396 00:22:20,100 --> 00:22:22,900 Thank you very much, Oliver. Thank you so much. 397 00:22:22,900 --> 00:22:25,300 I really enjoyed talking to you, and thanks very much for 398 00:22:25,300 --> 00:22:29,000 including me in your podcasts for more about geology b, as 399 00:22:29,000 --> 00:22:32,300 well as pictures and diagrams that illustrate this podcast. 400 00:22:32,700 --> 00:22:34,500 You can go to geology B.com.