1 00:00:00,120 --> 00:00:02,560 Speaker 1: Imagine just for a second that you are standing in 2 00:00:02,600 --> 00:00:06,480 a room and it's completely utterly pitch black. 3 00:00:06,919 --> 00:00:07,240 Speaker 2: Okay. 4 00:00:07,280 --> 00:00:08,759 Speaker 1: You can't see your hand in front of your face, 5 00:00:08,919 --> 00:00:11,119 you can't see the walls, you can't see the door. 6 00:00:11,160 --> 00:00:11,320 Speaker 2: But. 7 00:00:12,839 --> 00:00:15,160 Speaker 1: You know someone else is in there with you, you 8 00:00:15,240 --> 00:00:17,239 just know it. You can't see them, you can't hear 9 00:00:17,280 --> 00:00:20,679 them breathing, but you can feel I don't know, the 10 00:00:20,760 --> 00:00:22,760 floorboards shifting under a heavy weight. 11 00:00:22,920 --> 00:00:24,359 Speaker 2: That's a creepy thought, right. 12 00:00:24,679 --> 00:00:27,879 Speaker 1: You can feel the air sort of swirl as something 13 00:00:27,960 --> 00:00:30,760 massive moves past you. You can hear objects on a 14 00:00:30,800 --> 00:00:34,000 shelf across the room or rattling, even though you didn't 15 00:00:34,000 --> 00:00:37,640 touch them. It's that primal feeling of a presence you 16 00:00:37,679 --> 00:00:41,719 cannot verify with your eyes, but your gut, your instincts, 17 00:00:41,880 --> 00:00:44,280 they tell you it is undeniably real. 18 00:00:44,799 --> 00:00:47,320 Speaker 2: That is a terrifying image to start with. It's straight 19 00:00:47,320 --> 00:00:48,159 out of a horror movie. 20 00:00:48,280 --> 00:00:51,479 Speaker 1: It is, isn't it. It's so visceral. But that specific feeling, 21 00:00:51,520 --> 00:00:55,159 that sense of an invisible presence manipulating the environment, that 22 00:00:55,320 --> 00:00:57,719 is exactly what is happening in our solar system right now. 23 00:00:57,759 --> 00:00:58,799 Speaker 2: It's a perfect analogy. 24 00:00:59,039 --> 00:01:02,119 Speaker 1: The outer reach, the deep dark backyard of our sun 25 00:01:02,200 --> 00:01:05,959 are misbehaving, and we aren't talking about a few loose 26 00:01:06,079 --> 00:01:10,920 rocks tumbling around. We are talking about the fundamental architecture 27 00:01:10,959 --> 00:01:11,519 of our home. 28 00:01:11,680 --> 00:01:15,319 Speaker 2: Yeah, we're essentially looking at a cosmic crime scene. The 29 00:01:15,400 --> 00:01:19,159 suspect has fled or is hiding in the shadows, but 30 00:01:19,239 --> 00:01:23,400 they've left fingerprints everywhere. Fingerprints are like that massive gravitational 31 00:01:23,400 --> 00:01:26,079 fingerprints that simply shouldn't be there if the room was empty. 32 00:01:26,159 --> 00:01:28,079 Speaker 1: And that's what we are doing today. We are looking 33 00:01:28,120 --> 00:01:32,200 at those fingerprints. We're talking about objects way past Neptune, 34 00:01:32,239 --> 00:01:35,120 way out in the boonies that are clustering together in 35 00:01:35,200 --> 00:01:36,400 ways that defy. 36 00:01:36,319 --> 00:01:38,480 Speaker 2: All logic, all known logic. 37 00:01:38,159 --> 00:01:41,959 Speaker 1: Anyway, right, Mathematically, the chance of this happening by accident 38 00:01:42,040 --> 00:01:43,159 is less than one point. 39 00:01:42,959 --> 00:01:44,799 Speaker 2: One percent, less than a tenth of a percent. 40 00:01:45,040 --> 00:01:47,200 Speaker 1: So we aren't talking about a fluke. We are talking 41 00:01:47,239 --> 00:01:51,040 about a ghost in the gravity, a massive invisible object, 42 00:01:51,400 --> 00:01:54,680 what we're calling Planet nine, pulling strings from the darkness. 43 00:01:54,799 --> 00:01:56,799 Speaker 2: And that's the hook for me. It feels like a 44 00:01:56,799 --> 00:01:59,200 ghost story, you know, it feels like science fiction. But 45 00:01:59,280 --> 00:02:00,799 what we are going to talk talk about today is 46 00:02:00,840 --> 00:02:05,519 actually hard, rigorous physics. It's data It's a story about data, 47 00:02:06,079 --> 00:02:06,680 not magic. 48 00:02:07,640 --> 00:02:12,000 Speaker 1: Welcome to thrilling Threads. I am so excited for this one. Today. 49 00:02:12,120 --> 00:02:15,479 We are grabbing a massive stack of research, new studies 50 00:02:15,479 --> 00:02:19,479 from twenty twenty four, twenty twenty five, some archiabal data 51 00:02:19,479 --> 00:02:22,479 that's been dusted off, and some incredible physics to unravel 52 00:02:22,520 --> 00:02:25,360 perhaps the biggest mystery of our cosmic neighborhood. 53 00:02:25,560 --> 00:02:27,919 Speaker 2: Our mission today is really to complete the map. I 54 00:02:27,960 --> 00:02:30,719 think most people have this mental model of the Solar System, 55 00:02:31,280 --> 00:02:34,120 some eight planets, asteroid belt. 56 00:02:33,879 --> 00:02:36,639 Speaker 1: Maybe the Kuiper Belt, if they're paying attention in school. 57 00:02:36,319 --> 00:02:39,439 Speaker 2: Right, they're really paying attention, and then nothing, just empty 58 00:02:39,439 --> 00:02:42,960 space until the next star. But the data, it suggests 59 00:02:43,000 --> 00:02:44,719 we are missing a massive piece from the. 60 00:02:44,639 --> 00:02:46,919 Speaker 1: Puzzle and we are living through what you've called a 61 00:02:47,000 --> 00:02:49,960 Laverie moment, which sounds very fancy, but I want to 62 00:02:49,960 --> 00:02:52,560 break that down because it really frames this whole discussion. 63 00:02:52,759 --> 00:02:54,680 It does this isn't just about finding a rock. It's 64 00:02:54,680 --> 00:02:57,199 about a specific way of seeing the universe. 65 00:02:57,319 --> 00:03:00,000 Speaker 2: Right, that's absolutely right. To understand where we are now, 66 00:03:00,280 --> 00:03:03,120 we have to look back way back to eighteen forty six. Yeah, 67 00:03:03,159 --> 00:03:05,759 because this has happened before. It's the story of a 68 00:03:05,800 --> 00:03:08,319 French astronomer named Urban Leverier. 69 00:03:08,639 --> 00:03:10,960 Speaker 1: I love this story because it involves a guy with 70 00:03:11,000 --> 00:03:13,840 a pen defeating a bunch of people with telescopes. 71 00:03:14,000 --> 00:03:16,080 Speaker 2: It is the ultimate triumph of the nerd. 72 00:03:16,280 --> 00:03:17,159 Speaker 1: So what was happening? 73 00:03:17,599 --> 00:03:21,639 Speaker 2: Essentially, Yes, in the mid nineteenth century, astronomers had a problem. 74 00:03:22,400 --> 00:03:25,120 They were tracking the planet Uranus, which at the time 75 00:03:25,240 --> 00:03:29,319 was the furthest known planet, and Uranus was well, it 76 00:03:29,360 --> 00:03:31,280 was misbehaving. It wasn't following the rules. 77 00:03:31,319 --> 00:03:33,840 Speaker 1: And when you say rules, you mean Newton's laws of 78 00:03:33,879 --> 00:03:35,000 gravity exactly. 79 00:03:35,039 --> 00:03:38,479 Speaker 2: Newton's laws are very, very strict. They predict exactly where 80 00:03:38,520 --> 00:03:40,280 a planet should be based on the mass of the 81 00:03:40,319 --> 00:03:44,560 Sun and the other planets. It's a clockwork universe, supposedly. 82 00:03:44,680 --> 00:03:46,439 Speaker 1: But Urinus was off schedule. 83 00:03:46,520 --> 00:03:49,719 Speaker 2: It was accelerating and decelerating along its orbit in a 84 00:03:49,719 --> 00:03:52,360 way that made no sense. It was lagging behind where 85 00:03:52,360 --> 00:03:54,800 it should be that it would speed up. It was 86 00:03:54,840 --> 00:03:57,520 as if something invisible was tugging on it. 87 00:03:57,759 --> 00:04:00,520 Speaker 1: Okay, so the astronomers are scratching their heads. They're checking 88 00:04:00,560 --> 00:04:03,439 their telescopes, maybe assuming their charts are wrong or something right. 89 00:04:03,479 --> 00:04:05,719 Speaker 2: They're looking for an error in their own work. But 90 00:04:05,879 --> 00:04:09,719 Leverier sits down. And you have to remember, no supercomputers, 91 00:04:10,360 --> 00:04:15,000 no AI, just pen, paper and a candle, basically. 92 00:04:14,800 --> 00:04:16,480 Speaker 1: And a whole lot of mass. 93 00:04:16,160 --> 00:04:20,120 Speaker 2: An incredible amount of math. Yeah, and he crunches the numbers. 94 00:04:20,240 --> 00:04:23,639 He realized that the only explanation, the only thing that 95 00:04:23,720 --> 00:04:26,160 could make Urinus do that, was that there had to 96 00:04:26,160 --> 00:04:28,319 be another massive planet further. 97 00:04:28,079 --> 00:04:30,120 Speaker 1: Out, an unseen planet. 98 00:04:29,879 --> 00:04:34,519 Speaker 2: Totally unseen. Yeah. That was gravitationally interacting with Uranus. And 99 00:04:34,560 --> 00:04:37,120 he didn't just say there's a planet out there. He 100 00:04:37,240 --> 00:04:42,240 calculated its mass, its orbit, and the specific coordinates of 101 00:04:42,279 --> 00:04:43,600 this invisible object. 102 00:04:43,800 --> 00:04:45,720 Speaker 1: He drew a map to a place no one had 103 00:04:45,759 --> 00:04:46,240 ever seen. 104 00:04:46,399 --> 00:04:49,040 Speaker 2: She did. He sent a letter to a deservatory in 105 00:04:49,040 --> 00:04:52,959 Berlin saying, effectively, point your telescope at this specific patch 106 00:04:53,000 --> 00:04:54,519 of empty sky, you'll find it. 107 00:04:54,639 --> 00:04:56,800 Speaker 1: And this is the part that gives me chills every time, 108 00:04:56,959 --> 00:04:59,720 me too. They pointed the telescope aut his coordinates, and 109 00:04:59,759 --> 00:05:01,639 that very night, the very night. 110 00:05:01,519 --> 00:05:04,639 Speaker 2: They found Neptune. Just like that, what in one degree 111 00:05:04,680 --> 00:05:08,120 of whereas math said it would be one degree. That's 112 00:05:08,120 --> 00:05:10,199 the width of your pinky finger held at arms light. 113 00:05:10,399 --> 00:05:12,879 Speaker 1: That is just incredible. He found a planet with the 114 00:05:12,920 --> 00:05:13,680 tip of his pen. 115 00:05:14,160 --> 00:05:17,399 Speaker 2: He discovered a world without ever looking through a telescope, 116 00:05:18,079 --> 00:05:21,120 and that established this fundamental precedent. Gravity acts as a 117 00:05:21,120 --> 00:05:24,439 tracer for the invisible. Right, if the math doesn't balance, 118 00:05:24,519 --> 00:05:28,319 it means there is mass hiding somewhere. And today you 119 00:05:28,399 --> 00:05:30,879 fast forward nearly one hundred and eighty years and we're 120 00:05:30,920 --> 00:05:32,360 doing the exact same thing. 121 00:05:32,439 --> 00:05:36,000 Speaker 1: Okay, but this time it's not Urinus that's being pulled on. 122 00:05:36,040 --> 00:05:39,279 We've already accounted for Neptune in our models, correct, So 123 00:05:39,519 --> 00:05:41,920 what's the evidence now, what's misbehaving? 124 00:05:42,079 --> 00:05:44,879 Speaker 2: It's things much much further out. We were looking at 125 00:05:44,879 --> 00:05:48,800 the Kuiper Belt, which is that big ring of icy 126 00:05:48,800 --> 00:05:50,519 debris beyond Neptune. 127 00:05:50,120 --> 00:05:51,639 Speaker 1: Like where Pluto lives exactly. 128 00:05:51,720 --> 00:05:53,600 Speaker 2: But we're looking even beyond that at a group of 129 00:05:53,639 --> 00:05:56,720 extremely distant objects called said nooids. Said nooids. 130 00:05:56,800 --> 00:06:00,000 Speaker 1: Good name is that from the dwarf planet said Nah Yes, named. 131 00:05:59,800 --> 00:06:01,680 Speaker 2: After no which is one of the most famous of 132 00:06:01,720 --> 00:06:04,800 these distant objects. It's a dwarf planet candidate that takes 133 00:06:04,800 --> 00:06:06,240 over eleven thousand years. 134 00:06:06,040 --> 00:06:08,240 Speaker 1: To orbit the Sun eleven thousand years. 135 00:06:08,319 --> 00:06:10,319 Speaker 2: These are objects that spend most of their time in 136 00:06:10,360 --> 00:06:13,519 the deep, deep frieze of space. Now here's the key. 137 00:06:14,160 --> 00:06:17,759 In a stable eight planet Solar system, these objects should 138 00:06:17,759 --> 00:06:18,839 be scattered randomly. 139 00:06:18,920 --> 00:06:19,839 Speaker 1: Okay, that makes sense. 140 00:06:19,879 --> 00:06:23,079 Speaker 2: Their orbits should point in all different directions because of 141 00:06:23,399 --> 00:06:26,839 billions of years of chaotic gravitational interactions. 142 00:06:27,000 --> 00:06:29,079 Speaker 1: Right, it's like entropy. If you spill a bag of 143 00:06:29,120 --> 00:06:32,360 marbles on the floor, they'd roll everywhere. They wouldn't all 144 00:06:32,360 --> 00:06:34,439 just roll into one corner and line up neatly. 145 00:06:34,639 --> 00:06:37,199 Speaker 2: That's a perfect way to put it. Yeah, but when 146 00:06:37,199 --> 00:06:39,759 we look at these said nois, and we only know 147 00:06:39,800 --> 00:06:42,560 of a handful because they are so incredibly hard to see, 148 00:06:43,079 --> 00:06:44,360 that is exactly what they are doing. 149 00:06:44,519 --> 00:06:45,199 Speaker 1: Are lining up. 150 00:06:45,199 --> 00:06:49,439 Speaker 2: They're physically clustered in space. They're all swinging out in 151 00:06:49,480 --> 00:06:52,920 the same direction, and their orbits are all tilted at 152 00:06:53,000 --> 00:06:56,560 similar ankles away from the main plane of the Solar system. 153 00:06:57,040 --> 00:07:00,639 Speaker 1: And the odds of that being a coincidence are dely zero. 154 00:07:00,920 --> 00:07:03,720 Speaker 2: As we said, it's less than point one percent. So 155 00:07:03,759 --> 00:07:08,480 in twenty sixteen, two astronomers at Caltech, Constantin Batagen and 156 00:07:08,560 --> 00:07:14,079 Mike Brown, who are I mean, absolute titans of planetary astronomy. 157 00:07:14,079 --> 00:07:16,600 Speaker 1: Mike Brown is the guy who killed Pluto, right, He's the. 158 00:07:16,600 --> 00:07:18,319 Speaker 2: Guy he feels a little guilty about it, I think, 159 00:07:18,360 --> 00:07:19,800 so he wants to find a new planet to make 160 00:07:19,879 --> 00:07:20,240 up for it. 161 00:07:20,279 --> 00:07:21,199 Speaker 1: Fair enough, so. 162 00:07:21,120 --> 00:07:25,600 Speaker 2: They publish a model. They ran simulations and asked what 163 00:07:25,680 --> 00:07:26,839 could possibly. 164 00:07:26,360 --> 00:07:28,519 Speaker 1: Cause this, and the answer wasn't bad luck. 165 00:07:28,720 --> 00:07:32,680 Speaker 2: No. The simulations show that if you introduce a ninth planet, 166 00:07:33,160 --> 00:07:36,240 something roughly five to ten times the mass of the Earth, 167 00:07:36,759 --> 00:07:40,480 into the deep Outer Solar System, huh, it's gravity would 168 00:07:40,560 --> 00:07:43,639 naturally herd these objects. It acts like a sheep dog. 169 00:07:44,040 --> 00:07:48,160 It forces them into these synchronized, clustered orbits over millions 170 00:07:48,199 --> 00:07:49,399 and millions of years. 171 00:07:49,560 --> 00:07:51,720 Speaker 1: So without the planet, the system makes no sense. 172 00:07:51,800 --> 00:07:54,000 Speaker 2: It makes no sense. But you add the planet and 173 00:07:54,040 --> 00:07:55,560 everything clicks perfectly into place. 174 00:07:55,639 --> 00:07:58,000 Speaker 1: Okay, so let's profile the suspect. We know it's there 175 00:07:58,120 --> 00:08:00,319 because of the math, But what is it? What are 176 00:08:00,319 --> 00:08:03,680 we actually looking for? Because Planet nine sounds a little. 177 00:08:04,279 --> 00:08:07,720 Speaker 2: Generic, it's a working title. What we are really looking 178 00:08:07,720 --> 00:08:09,040 for is a super. 179 00:08:08,639 --> 00:08:11,240 Speaker 1: Earth, which is a term I hear a lot, especially 180 00:08:11,279 --> 00:08:14,079 in science fiction, and I think people picture like crypton 181 00:08:14,439 --> 00:08:17,439 or something, But what does it mean physically in astronomy. 182 00:08:17,759 --> 00:08:20,959 Speaker 2: It's actually a pretty simple definition. It refers strictly to mass. 183 00:08:21,600 --> 00:08:23,959 A super Earth is a planet that is larger than 184 00:08:24,040 --> 00:08:27,800 Earth but smaller than Neptune. So Neptune is about seventeen 185 00:08:27,879 --> 00:08:32,120 Earth masses. Earth is well one Earth mass. We're looking 186 00:08:32,120 --> 00:08:34,360 for something in that sweet spot that five to ten 187 00:08:34,519 --> 00:08:35,559 Earth mass range. 188 00:08:35,639 --> 00:08:37,919 Speaker 1: And here's where it gets really really interesting for me 189 00:08:38,039 --> 00:08:41,159 looking at the context you provided, when we look outside 190 00:08:41,200 --> 00:08:44,799 our Solar System at other star systems yet exoplanets, Yeah, 191 00:08:44,879 --> 00:08:49,279 super earths are the most common type of planet out there. 192 00:08:49,440 --> 00:08:51,039 They are literally everywhere. 193 00:08:51,120 --> 00:08:53,919 Speaker 2: They are the standard galactic furniture. If you look at 194 00:08:53,919 --> 00:08:56,840 the data from the Kepler Space Telescope or the Test mission, 195 00:08:57,399 --> 00:09:00,759 super earths are the medium planet. They are the fault model, 196 00:09:00,919 --> 00:09:03,399 but we don't have one currently. No, we are the 197 00:09:03,440 --> 00:09:06,879 odd ones out. Our Solar system has small, rocky worlds 198 00:09:06,919 --> 00:09:09,759 like Earth and Mars, and then we have massive gas 199 00:09:09,799 --> 00:09:13,279 giants like Jupiter and Saturn. We are missing that whole 200 00:09:13,320 --> 00:09:14,320 middleweight category. 201 00:09:14,399 --> 00:09:16,840 Speaker 1: It's like walking into a house that has tiny footstools 202 00:09:16,879 --> 00:09:19,919 and massive sectional sofas but no regular sized chairs. 203 00:09:20,000 --> 00:09:21,799 Speaker 2: That's a great way to put it. It's a genuine 204 00:09:21,919 --> 00:09:25,840 architectural gap in our Solar system's design. Finding Planet nine 205 00:09:25,840 --> 00:09:27,919 would actually make our Solar system normal. 206 00:09:27,799 --> 00:09:29,360 Speaker 1: It would stop us from being an anomaly. 207 00:09:29,720 --> 00:09:32,399 Speaker 2: It would stop us from being the weirdos and align 208 00:09:32,440 --> 00:09:35,480 our architecture with what we see happening all across the galaxy. 209 00:09:35,679 --> 00:09:38,639 Speaker 1: So it's big, five to ten times the massive Earth. 210 00:09:39,039 --> 00:09:42,159 But where is it? Because if it's that big, shouldn't 211 00:09:42,200 --> 00:09:44,279 we have I don't know, tripped over it by now? 212 00:09:44,360 --> 00:09:48,000 Speaker 2: Well, it is incredibly far away. Its orbit is highly 213 00:09:48,039 --> 00:09:51,360 elongated or eccentric. It's not a nice circle like Earth's. 214 00:09:51,639 --> 00:09:55,360 It takes somewhere between ten thousand and twenty thousand years 215 00:09:55,720 --> 00:09:57,120 to circle the Sun just. 216 00:09:57,080 --> 00:10:00,679 Speaker 1: One time, twenty thousand years for one year. That is 217 00:10:00,799 --> 00:10:03,320 just it's mind boggling. That means the last time it 218 00:10:03,360 --> 00:10:05,480 was in this part of its orbit, humans were just 219 00:10:05,559 --> 00:10:06,759 figuring them out agriculture. 220 00:10:06,799 --> 00:10:09,559 Speaker 2: Even earlier than that, maybe we were still paintying gabes. Wow. 221 00:10:09,720 --> 00:10:11,039 To give you a sense of scale, we use a 222 00:10:11,039 --> 00:10:14,600 measurement called an astronomical unit, or AU. One AU is 223 00:10:14,639 --> 00:10:16,200 the distance from the Earth to the Sun. 224 00:10:16,120 --> 00:10:18,240 Speaker 1: Right about ninety three million miles. 225 00:10:17,960 --> 00:10:20,000 Speaker 2: So at its closest approach to the Sun, what we 226 00:10:20,039 --> 00:10:23,519 call parahelium, planet nine is about two hundred AU away, 227 00:10:23,519 --> 00:10:26,399 so two hundred times further than us, but at its 228 00:10:26,559 --> 00:10:28,919 furthest point, it's a felion. It swings out to maybe 229 00:10:29,000 --> 00:10:30,519 a thousand au. 230 00:10:30,279 --> 00:10:32,480 Speaker 1: One thousand, and for comparison, Pluto is what thirty or 231 00:10:32,480 --> 00:10:34,279 forty au away exactly. 232 00:10:34,600 --> 00:10:38,320 Speaker 2: Pluto's orbit varies between about thirty and fifty AU. So 233 00:10:38,399 --> 00:10:41,200 Pluto is practically in our backyard compared to this thing. 234 00:10:41,559 --> 00:10:43,759 This object is in the deep deep freeze. 235 00:10:43,840 --> 00:10:47,200 Speaker 1: Okay. So we have this massive object five to ten 236 00:10:47,279 --> 00:10:50,000 times the size of Earth. We know roughly where it 237 00:10:50,039 --> 00:10:53,360 should be because of the math. This leads to the question. 238 00:10:53,480 --> 00:10:56,360 I think every single listener is screaming at their device 239 00:10:56,440 --> 00:10:56,840 right now. 240 00:10:56,879 --> 00:10:57,480 Speaker 2: I know the one. 241 00:10:57,600 --> 00:10:59,679 Speaker 1: Why haven't we seen it? Why can't we just point 242 00:10:59,720 --> 00:11:02,799 the Hupace telescope at that spot and snap a picture? 243 00:11:03,080 --> 00:11:05,639 Speaker 2: That is the most common question. If it's so big, 244 00:11:05,919 --> 00:11:09,279 why is it invisible? And the answer lies in the 245 00:11:09,320 --> 00:11:13,279 fundamental physics of light, specifically a little something called the 246 00:11:13,320 --> 00:11:14,159 inverse square law. 247 00:11:14,480 --> 00:11:17,639 Speaker 1: Okay, let's unpack the inverse square law, because this explains 248 00:11:17,679 --> 00:11:20,440 why space exploration is so hard in general. It's not 249 00:11:20,519 --> 00:11:22,960 just that things get a little dimmer further away. 250 00:11:23,039 --> 00:11:25,240 Speaker 2: No, it's not a linear dimming. Think about a simple 251 00:11:25,320 --> 00:11:28,360 light bulb or a candle. If you're standing one foot 252 00:11:28,399 --> 00:11:30,919 away from it, it's bright. Sure, if you step back 253 00:11:30,919 --> 00:11:33,080 to two feet away, it's not just half as bright, 254 00:11:33,120 --> 00:11:35,600 it's one quarter as bright. The intensity of the light 255 00:11:35,679 --> 00:11:36,799 drops off with the square of the. 256 00:11:36,799 --> 00:11:39,120 Speaker 1: Distance, so if you go three feet away, it's one 257 00:11:39,200 --> 00:11:39,919 ninth is bright. 258 00:11:40,279 --> 00:11:44,200 Speaker 2: Precisely. Now apply that to the sun. Sunlight has to 259 00:11:44,240 --> 00:11:47,440 travel let's pick a number, say seven hundred au out 260 00:11:47,440 --> 00:11:48,440 to hit planet nine. 261 00:11:48,600 --> 00:11:49,360 Speaker 1: That's a long way. 262 00:11:49,519 --> 00:11:51,840 Speaker 2: By the time the sunlight gets there, the light is 263 00:11:52,000 --> 00:11:55,360 incredibly weak. It's spread out over a huge area, so. 264 00:11:55,320 --> 00:11:57,399 Speaker 1: It's basically twilight or even darker. 265 00:11:57,120 --> 00:12:00,519 Speaker 2: On this planet, much much darker. Imagine a single candle 266 00:12:00,519 --> 00:12:03,159 in the middle of a football stadium at night. But then, 267 00:12:03,679 --> 00:12:06,559 and this is the absolute kicker, that tiny amount of 268 00:12:06,639 --> 00:12:09,639 light has to reflect off the surface of the planet 269 00:12:09,799 --> 00:12:12,840 and travel another seven hundred AU all the way back 270 00:12:12,879 --> 00:12:14,120 to our telescopes on Earth. 271 00:12:14,159 --> 00:12:15,799 Speaker 1: So the dimming happens twice. 272 00:12:16,000 --> 00:12:17,840 Speaker 2: It gets hit by the inverse square law on the 273 00:12:17,840 --> 00:12:19,320 way out and again on the way. 274 00:12:19,120 --> 00:12:21,120 Speaker 1: Back, so it's really the inverse fourth power. 275 00:12:21,159 --> 00:12:24,720 Speaker 2: Then, effectively, yes, the result is that planet nine is 276 00:12:24,840 --> 00:12:28,440 thousands upon thousands of times dimmer than even distant objects 277 00:12:28,480 --> 00:12:32,440 like Pluto to a standard optical telescope that's looking for 278 00:12:32,480 --> 00:12:35,879 a reflected sunlight. It is effectively a black object sitting 279 00:12:35,879 --> 00:12:37,159 against a black background. 280 00:12:37,240 --> 00:12:39,159 Speaker 1: So looking for it with a normal camera is like 281 00:12:39,200 --> 00:12:41,159 looking for a piece of coal and a dark cellar 282 00:12:41,200 --> 00:12:43,080 at midnight while wearing sunglasses. 283 00:12:43,519 --> 00:12:45,240 Speaker 2: Yes, it's just incredibly difficult. 284 00:12:45,279 --> 00:12:48,960 Speaker 1: Okay, that makes sense. So that strategy is out, which. 285 00:12:48,799 --> 00:12:52,000 Speaker 2: Is why researchers have shifted their strategy. They aren't just 286 00:12:52,039 --> 00:12:55,320 looking for reflected light anymore. They are looking for heat 287 00:12:55,519 --> 00:12:59,440 and for red exactly. Even a very cold planet way 288 00:12:59,480 --> 00:13:02,360 out in the vall still retains some heat from its 289 00:13:02,399 --> 00:13:06,720 formation billions of years ago. It's warmer than the absolute 290 00:13:06,799 --> 00:13:11,200 zero of empty space, so it should glow faintly in 291 00:13:11,240 --> 00:13:12,240 the infrared spectrum. 292 00:13:12,279 --> 00:13:14,679 Speaker 1: So we just need to put on our heat vision goggles. Basically, 293 00:13:14,759 --> 00:13:16,440 that sounds much easier. 294 00:13:16,039 --> 00:13:18,080 Speaker 2: You would think so, But of course there's a catch there. 295 00:13:18,120 --> 00:13:20,000 Chair This was always a catch, and the catch is 296 00:13:20,039 --> 00:13:20,720 the Milky Way. 297 00:13:21,159 --> 00:13:22,879 Speaker 1: Wait, our own galaxy is in the way. 298 00:13:22,960 --> 00:13:26,639 Speaker 2: How well, the galactic plane, that bright, hazy band you 299 00:13:26,639 --> 00:13:28,720 can see in the night sky from a dark location 300 00:13:29,360 --> 00:13:32,120 is crowded with billions of stars and clouds of dust 301 00:13:32,159 --> 00:13:36,440 and gas. All of that stuff emits infrared radiation. It's 302 00:13:36,639 --> 00:13:37,799 infrared noise. 303 00:13:37,559 --> 00:13:38,639 Speaker 1: So it's like static. 304 00:13:38,679 --> 00:13:41,840 Speaker 2: It's like trying to hear a specific faint whisper and 305 00:13:41,919 --> 00:13:45,679 a screaming stadium full of people. If Planet nine happens 306 00:13:45,720 --> 00:13:47,399 to be passing in front of the dense part of 307 00:13:47,440 --> 00:13:49,879 the Milky Way in its orbit, it's hidden. It's completely 308 00:13:50,000 --> 00:13:54,399 hidden behind this wall of infrared noise. And unfortunately, the 309 00:13:54,480 --> 00:13:57,600 predicted orbit takes it right across the galactic plane. 310 00:13:57,639 --> 00:14:00,039 Speaker 1: Of course it does. So it's faint, it's far, and 311 00:14:00,039 --> 00:14:03,360 it might be hiding in the galactic crowd. But despite 312 00:14:03,399 --> 00:14:06,879 all of that, we have some major breakthroughs happening right now. 313 00:14:07,000 --> 00:14:07,240 Speaker 2: You do. 314 00:14:07,600 --> 00:14:10,399 Speaker 1: Let's talk about the twenty twenty five study. I believe 315 00:14:10,399 --> 00:14:13,720 it was led by a researcher named Terry Longfan. This 316 00:14:13,799 --> 00:14:17,480 felt like a moment where the detective work really leveled up. 317 00:14:17,519 --> 00:14:20,120 Speaker 2: This is a brilliant piece of science. They used what 318 00:14:20,159 --> 00:14:22,559 we call the shift in stack method, but they did 319 00:14:22,559 --> 00:14:24,080 it using archival data. 320 00:14:24,159 --> 00:14:26,720 Speaker 1: I love this because it shows you don't always need 321 00:14:26,759 --> 00:14:30,039 a new, shiny, billion dollar telescope. Sometimes you just need 322 00:14:30,080 --> 00:14:32,159 to look at the old tapes differently precisely. 323 00:14:32,200 --> 00:14:35,759 Speaker 2: It's so clever. They took data from the IRAS satellite, 324 00:14:35,799 --> 00:14:39,039 which was an infrared satellite that scanned the sky way 325 00:14:39,039 --> 00:14:40,240 back in nineteen eighty three. 326 00:14:40,360 --> 00:14:41,840 Speaker 1: Okay, that's old data. 327 00:14:41,639 --> 00:14:43,639 Speaker 2: Very old, and they compared it with data from the 328 00:14:43,679 --> 00:14:47,399 Ocardi satellite, which is a Japanese infrared satellite that flew 329 00:14:47,440 --> 00:14:48,440 in two thousand and six. 330 00:14:48,679 --> 00:14:52,200 Speaker 1: That's a twenty three year gap between the two pictures, and. 331 00:14:52,080 --> 00:14:56,120 Speaker 2: That gap is the key. Remember, Planet nine moves, but 332 00:14:56,240 --> 00:14:59,919 from our perspective, it moves very, very slowly across the sky. 333 00:15:00,519 --> 00:15:03,440 In a day or even a year, it barely budget 334 00:15:03,480 --> 00:15:07,200 against the background stars. But in twenty three years it 335 00:15:07,320 --> 00:15:09,080 moves just enough to be noticeable. 336 00:15:09,200 --> 00:15:11,720 Speaker 1: So if you layer the two images on top of 337 00:15:11,759 --> 00:15:15,159 each other, you shift and stack them. The stars should 338 00:15:15,159 --> 00:15:18,200 stay still, but the planet should jump from one spot 339 00:15:18,240 --> 00:15:19,440 to another exactly. 340 00:15:19,720 --> 00:15:22,080 Speaker 2: You layer the images to digitally cancel out all the 341 00:15:22,120 --> 00:15:25,960 static background noise, the stars, the distant galaxies, and you 342 00:15:26,000 --> 00:15:28,559 look for the one faint pixel that shifted position. 343 00:15:28,799 --> 00:15:31,000 Speaker 1: It's like looking at two frames of a movie. Real 344 00:15:31,279 --> 00:15:34,080 the background scenery doesn't change, but the actor moves from 345 00:15:34,159 --> 00:15:34,759 left to right. 346 00:15:35,159 --> 00:15:37,200 Speaker 2: That's the idea, and they found something. 347 00:15:37,200 --> 00:15:38,120 Speaker 1: They found a candidate. 348 00:15:38,200 --> 00:15:40,919 Speaker 2: They identified a very promising signal that appears in both 349 00:15:40,960 --> 00:15:43,120 data sets from both nineteen eighty three and two thousand 350 00:15:43,159 --> 00:15:46,200 and six, and its movement pattern matches the mathematical prediction 351 00:15:46,279 --> 00:15:47,600 for planet nine perfectly. 352 00:15:47,759 --> 00:15:49,159 Speaker 1: But I can hear a butt in your. 353 00:15:49,120 --> 00:15:51,919 Speaker 2: Voice, but it is extremely faint. It sits right at 354 00:15:51,919 --> 00:15:54,120 the very very edge of the detection limits for those 355 00:15:54,120 --> 00:15:55,919 old instruments. It's a ghost of a. 356 00:15:55,879 --> 00:15:57,240 Speaker 1: Signal, so it could be noise. 357 00:15:57,559 --> 00:15:59,919 Speaker 2: It could be a glitch in the data processing, or 358 00:16:00,120 --> 00:16:03,360 a random cosmic ray hitting the sensor in just the 359 00:16:03,480 --> 00:16:07,279 right way in both data sets, though that's unlikely. It's 360 00:16:07,279 --> 00:16:10,159 the most promising lead we have from archival data, but 361 00:16:10,200 --> 00:16:12,679 it requires conformation. We need a better look with a 362 00:16:12,720 --> 00:16:15,360 more powerful instrument to be sure it's a solid body. 363 00:16:15,480 --> 00:16:18,120 Speaker 1: So that's the visual hunt. We have a maybe, a 364 00:16:18,279 --> 00:16:21,639 very exciting maybe. But the mathematical case just got a 365 00:16:21,759 --> 00:16:22,679 huge upgrade too. 366 00:16:23,000 --> 00:16:23,440 Speaker 2: It did. 367 00:16:23,639 --> 00:16:27,480 Speaker 1: In twenty twenty four, Vatagen and Brown, the original duo, 368 00:16:27,679 --> 00:16:30,519 they dropped a new paper, and this one involves something 369 00:16:30,559 --> 00:16:32,759 called neptune crossing TNOs. 370 00:16:33,279 --> 00:16:36,120 Speaker 2: This for me, is arguably even more compelling than the 371 00:16:36,120 --> 00:16:38,080 clustering of the said noise we discussed earlier. 372 00:16:38,159 --> 00:16:41,279 Speaker 1: Okay, let's break it down. What is a Neptune crosser. 373 00:16:41,399 --> 00:16:43,519 It sounds like a traffic violation in space. 374 00:16:43,679 --> 00:16:46,039 Speaker 2: It's pretty much exactly what it sounds like. These are 375 00:16:46,120 --> 00:16:50,360 trans Neptunian objects or tno so icy bodies in the 376 00:16:50,399 --> 00:16:54,600 Kuiper Belt. But their orbits are so eccentric, so stretched out, 377 00:16:54,759 --> 00:16:57,360 that they periodically cross inside the orbit of Neptune. 378 00:16:57,399 --> 00:16:58,159 Speaker 1: And that's dangerous. 379 00:16:58,240 --> 00:16:58,440 Speaker 2: Right. 380 00:16:58,519 --> 00:17:01,039 Speaker 1: Neptune is a gas giant's huge. If you get too 381 00:17:01,039 --> 00:17:03,759 close to that, it's gravity should what kick you out? 382 00:17:04,119 --> 00:17:08,400 Speaker 2: Right. Neptune is a bully, It's a gravitational monster. Under 383 00:17:08,440 --> 00:17:13,160 normal physics, if a small icy rock crosses Neptune's path, 384 00:17:13,759 --> 00:17:16,720 one of two things is going to happen, and quickly. Okay, 385 00:17:17,000 --> 00:17:20,480 Either Neptune's gravity swallows it, pulling it in to crash 386 00:17:20,519 --> 00:17:24,759 into the planet, or Neptune acts like a gravitational sling 387 00:17:24,839 --> 00:17:27,440 shot and flings it out of the Solar System entirely. 388 00:17:27,640 --> 00:17:29,359 Speaker 1: So these objects should not be stable. 389 00:17:29,519 --> 00:17:31,720 Speaker 2: These should not exist. They should have been cleaned up 390 00:17:31,720 --> 00:17:34,240 and vanished within a few million years of the Solar 391 00:17:34,279 --> 00:17:35,079 System's formation. 392 00:17:35,279 --> 00:17:37,559 Speaker 1: But they're still there. We see them, we see them. 393 00:17:37,599 --> 00:17:39,640 Speaker 2: They exist. Yeah, and that was a huge puzzle for 394 00:17:39,640 --> 00:17:42,759 a long time. Why hasn't Neptune cleaned up its neighborhood. 395 00:17:43,000 --> 00:17:46,839 Speaker 1: So Beigeen and Brown ran these things called n body simulations, 396 00:17:46,839 --> 00:17:50,039 which or what they're massive computer models that calculate the 397 00:17:50,039 --> 00:17:53,720 gravitational pull of every object on every other object over 398 00:17:53,799 --> 00:17:55,319 billions and billions of years. 399 00:17:55,400 --> 00:17:56,759 Speaker 2: And what did the simulation say. 400 00:17:56,920 --> 00:17:58,720 Speaker 1: It showed that if you only have the eight known 401 00:17:58,759 --> 00:18:03,039 planets in your model, the Neptune crossing objects vanish every time. 402 00:18:03,359 --> 00:18:06,640 They simply cannot survive for the four point five billion 403 00:18:06,720 --> 00:18:08,079 year age of the Solar System. 404 00:18:08,319 --> 00:18:11,160 Speaker 2: But if you add planet nine into the simulation. 405 00:18:10,720 --> 00:18:12,519 Speaker 1: The bodyguard arrise, bodyguard arrives. 406 00:18:12,880 --> 00:18:17,240 Speaker 2: Planet nine acts as a shepherd. Its gravity, even from 407 00:18:17,319 --> 00:18:21,720 way out there, exudes this subtle but persistent pull that 408 00:18:21,880 --> 00:18:24,920 keeps these objects in a state of what we call resonance. 409 00:18:25,759 --> 00:18:28,799 It gently nudges them, preventing them from getting too close 410 00:18:28,839 --> 00:18:30,200 to Neptune on their orbits. 411 00:18:30,480 --> 00:18:34,720 Speaker 1: So Planet nine is actively protecting these erratic objects from Neptune. 412 00:18:34,759 --> 00:18:38,880 Speaker 2: It's actively managing their orbits. And the statistical confidence here 413 00:18:39,160 --> 00:18:41,599 is what blew everyone away. They found the result was 414 00:18:41,799 --> 00:18:42,480 five sigma. 415 00:18:42,559 --> 00:18:45,599 Speaker 1: Five sigma. Now, for listeners who don't speak statistics, what 416 00:18:45,640 --> 00:18:48,160 does that actually mean? I know sigma from like six 417 00:18:48,160 --> 00:18:49,759 sigma in business, But this is physics. 418 00:18:49,920 --> 00:18:52,599 Speaker 2: Five sigma is the gold standard in science. It's the 419 00:18:52,599 --> 00:18:56,119 official threshold for declaring a discovery definitive. To give you 420 00:18:56,200 --> 00:18:59,039 some context, the discovery of the Higgs boson the god 421 00:18:59,079 --> 00:19:01,079 particle five sigma discovery. 422 00:19:01,119 --> 00:19:01,799 Speaker 1: So it's a big deal. 423 00:19:02,039 --> 00:19:04,240 Speaker 2: It means there is a one in three point five 424 00:19:04,319 --> 00:19:06,880 million chance that this is a statistical fluke. 425 00:19:06,880 --> 00:19:08,279 Speaker 1: One in three point five million. 426 00:19:08,720 --> 00:19:12,039 Speaker 2: Yes, so this moves planet Metane from Hey, this is 427 00:19:12,079 --> 00:19:15,519 a possible explanation for some weird clustering we see to 428 00:19:16,519 --> 00:19:19,240 this is a mathematical requirement for the Solar System to 429 00:19:19,359 --> 00:19:21,039 exist as we currently observe it. 430 00:19:21,240 --> 00:19:23,839 Speaker 1: That is heavy. It's not just a guess anymore. The 431 00:19:23,880 --> 00:19:27,079 math is saying the building falls down without this pillar exactly. 432 00:19:27,519 --> 00:19:29,880 Speaker 2: And this study was so crucial because it addressed the 433 00:19:29,920 --> 00:19:32,960 skeptics who would say, well, maybe you're just looking for 434 00:19:32,960 --> 00:19:36,680 clustered objects in the wrong places. This isn't about observational bias. 435 00:19:36,680 --> 00:19:39,599 It's about the fundamental physics of survival. For these objects. 436 00:19:39,720 --> 00:19:42,119 They shouldn't be here, but they are. Okay. 437 00:19:42,160 --> 00:19:45,480 Speaker 1: So the math is screaming it's there. The archival data 438 00:19:45,519 --> 00:19:48,799 is whispering. I think I see it, but we want 439 00:19:48,799 --> 00:19:51,160 to see it for real. We want the mugshot, We 440 00:19:51,200 --> 00:19:53,880 want the picture. Enter the eye of the future. The 441 00:19:54,000 --> 00:19:56,039 verraa C. Reuben Observatory. 442 00:19:56,359 --> 00:19:59,319 Speaker 2: This is the game changer as of early twenty twenty six. 443 00:19:59,440 --> 00:20:02,440 It is full operational and chili and it is an 444 00:20:02,480 --> 00:20:03,440 absolute beast. 445 00:20:03,559 --> 00:20:05,480 Speaker 1: It's not just a normal telescope, right, It's not like 446 00:20:05,519 --> 00:20:06,680 looking through a small tube. 447 00:20:06,839 --> 00:20:08,599 Speaker 2: No, not at all. Think of it as a high 448 00:20:08,599 --> 00:20:11,680 speed mapping system. It has a huge eight point four 449 00:20:11,720 --> 00:20:14,880 meter mirror. But the camera is the real star of 450 00:20:14,880 --> 00:20:16,880 the show. It's a three point two gigapick. 451 00:20:16,960 --> 00:20:19,400 Speaker 1: The camera three point two gigapixels. My phone has what 452 00:20:19,480 --> 00:20:21,319 twelve megapixels? Maybe forty eight. 453 00:20:21,519 --> 00:20:24,440 Speaker 2: It is the largest digital sensor ever built for astronomy. 454 00:20:25,000 --> 00:20:27,400 To put another way, the field of view is so 455 00:20:27,599 --> 00:20:30,519 wide it can capture an area of the sky equivalent 456 00:20:30,559 --> 00:20:33,319 to forty full moons in a single snapshot. 457 00:20:33,519 --> 00:20:35,759 Speaker 1: Forty full moons. And what is it doing with all 458 00:20:35,799 --> 00:20:36,279 that power? 459 00:20:36,359 --> 00:20:39,039 Speaker 2: It's creating what they call a cosmic movie. It scans 460 00:20:39,079 --> 00:20:42,319 the entire southern sky every few nights, over and over 461 00:20:42,359 --> 00:20:44,000 and over again. Yeah, for ten years. 462 00:20:44,079 --> 00:20:46,119 Speaker 1: So instead of staring at one tiny spot for a 463 00:20:46,119 --> 00:20:46,920 long time like. 464 00:20:46,920 --> 00:20:49,839 Speaker 2: Hubble does, right, Hubble has a tiny pinprick field of view. 465 00:20:50,000 --> 00:20:52,519 Speaker 1: Rubin is monitoring everything. 466 00:20:52,119 --> 00:20:54,920 Speaker 2: All the time, everything, And this is the perfect strategy 467 00:20:54,920 --> 00:20:57,480 for finding something like planet nine. Because Planet nine is 468 00:20:57,519 --> 00:20:59,920 faint and it moves right, the Ruben observe itt to 469 00:21:00,119 --> 00:21:02,359 or he can detect objects down to a brightness level 470 00:21:02,440 --> 00:21:05,759 or magnitude of twenty four point five in a single shot, 471 00:21:05,880 --> 00:21:08,599 which is already very faint. But because it visits the 472 00:21:08,599 --> 00:21:11,440 same patch of sky over eight hundred times during its survey, 473 00:21:11,640 --> 00:21:13,519 you can stack the images or back to the shift 474 00:21:13,519 --> 00:21:14,279 in status on. 475 00:21:14,279 --> 00:21:18,039 Speaker 1: A massive industrial scale. When you stack a year's worth 476 00:21:18,039 --> 00:21:21,559 of Reuben data, the sensitivity goes down to magnitude twenty 477 00:21:21,559 --> 00:21:24,799 seven point eight, which means in plain English, it means 478 00:21:25,000 --> 00:21:28,880 it can see things that are incredibly, unbelievably dim. Planet 479 00:21:28,960 --> 00:21:31,759 nine is expected to be about six hundred times fainter 480 00:21:31,839 --> 00:21:34,920 than Pluto. Reuben can see that, no problem, and. 481 00:21:34,839 --> 00:21:37,200 Speaker 2: We already have a proof of concept that the system works. 482 00:21:37,480 --> 00:21:39,160 From January of twenty twenty six. 483 00:21:39,279 --> 00:21:42,240 Speaker 1: Yes, the very first pure viewed paper to come out 484 00:21:42,279 --> 00:21:46,559 of the Reuben Observatory Science operations identified a new fast 485 00:21:46,599 --> 00:21:48,839 spinning asteroid called twenty twenty five. 486 00:21:49,319 --> 00:21:51,559 Speaker 2: M N forty five, So a different object. 487 00:21:51,720 --> 00:21:54,559 Speaker 1: Yes, that was much closer between Mars and Jupiter. But 488 00:21:54,640 --> 00:21:57,240 it proved the software works. It proved the automated system 489 00:21:57,279 --> 00:21:59,960 can isolate a single moving object from millions upon million 490 00:22:00,240 --> 00:22:01,200 of static stars. 491 00:22:01,400 --> 00:22:03,240 Speaker 2: So the trap is set, the camera. 492 00:22:03,039 --> 00:22:05,599 Speaker 1: Is rolling, the trap is set, the timeline is promising. 493 00:22:06,000 --> 00:22:07,799 If planet nine is where we think it is and 494 00:22:07,880 --> 00:22:10,119 as bright as we think it is, Ruben has a 495 00:22:10,240 --> 00:22:12,720 very strong chance of identifying it within the first one 496 00:22:12,720 --> 00:22:15,680 to two years of the survey. We're literally just waiting 497 00:22:15,680 --> 00:22:18,359 for the computer to ping. Now, in the spirit of 498 00:22:18,359 --> 00:22:20,279 good science, we have to look at the other side 499 00:22:20,279 --> 00:22:22,599 of the coin. Of course, is there any chance planet 500 00:22:22,680 --> 00:22:26,079 nine isn't a planet? What are the skeptics saying? Because 501 00:22:26,079 --> 00:22:28,400 I know there are some pretty wild alternative theories that 502 00:22:28,440 --> 00:22:29,960 don't involve a giant rock. 503 00:22:30,200 --> 00:22:35,000 Speaker 2: Absolutely, science requires us to challenge every hypothesis. You have 504 00:22:35,079 --> 00:22:36,559 to try to break the theory to see if it 505 00:22:36,599 --> 00:22:39,440 stands up. And there are three main alternatives on the 506 00:22:39,480 --> 00:22:40,119 table right now. 507 00:22:40,200 --> 00:22:43,799 Speaker 1: Okay, let's run through them. Theory A, the laws of 508 00:22:43,839 --> 00:22:44,960 gravity are wrong. 509 00:22:45,480 --> 00:22:48,559 Speaker 2: This is a concept known as m own ND modified 510 00:22:48,640 --> 00:22:53,039 Newtonian dynamics. The core idea is that at very very 511 00:22:53,079 --> 00:22:55,720 low accelerations, like what you'd experienced way out in the 512 00:22:55,759 --> 00:22:59,079 deep boonies of the Solar System, gravity just doesn't behave 513 00:22:59,119 --> 00:23:00,799 the way Newton ORNs Steins said it does. 514 00:23:01,119 --> 00:23:03,000 Speaker 1: So we don't need a new planet, we just need 515 00:23:03,119 --> 00:23:04,279 new math exactly. 516 00:23:04,720 --> 00:23:07,319 Speaker 2: A twenty twenty three study by researchers named Brown and 517 00:23:07,400 --> 00:23:11,279 Mother suggested that the Milky Way's own galactic gravitational field 518 00:23:11,519 --> 00:23:13,880 could be tugging on the outer Solar System in a 519 00:23:13,920 --> 00:23:16,440 subtle way that mimics the pull of a planet. They 520 00:23:16,480 --> 00:23:18,200 call it the external field effect. 521 00:23:18,400 --> 00:23:20,279 Speaker 1: So the ghost in the room is the whole galaxy. 522 00:23:20,440 --> 00:23:24,079 Speaker 2: It's a valid theory, but it requires rewriting fundamental physics, 523 00:23:24,720 --> 00:23:28,839 and generally in science we follow Oukham's razor. The simplest 524 00:23:28,880 --> 00:23:30,880 explanation is usually the best. 525 00:23:30,680 --> 00:23:33,279 Speaker 1: And a planet is simpler than new physics. 526 00:23:33,519 --> 00:23:36,640 Speaker 2: Planet nine just requires adding one more rock to the inventory. 527 00:23:37,279 --> 00:23:41,359 Monda requires changing the fundamental laws of the universe. Okham's 528 00:23:41,440 --> 00:23:43,319 razor usually favors the rock. 529 00:23:43,519 --> 00:23:47,160 Speaker 1: Fair enough, okay. Theory B. This one is my favorite. 530 00:23:47,519 --> 00:23:49,480 The primordial black hole. 531 00:23:49,880 --> 00:23:53,000 Speaker 2: This one is fun. It was proposed by Unwinded Schultz. 532 00:23:53,440 --> 00:23:55,839 They suggest that the mass out there isn't a planet 533 00:23:55,920 --> 00:23:58,680 at all, but a black hole the size of a grapefruit. 534 00:23:58,799 --> 00:24:02,160 Speaker 1: A grapefruit size black hole that just sounds terrifying. 535 00:24:02,319 --> 00:24:04,440 Speaker 2: It would have the same mass as five to ten Earth, 536 00:24:04,799 --> 00:24:07,279 but compressed it to a tiny, tiny point. It would 537 00:24:07,319 --> 00:24:10,119 explain the gravity perfectly, and it would also perfectly explain 538 00:24:10,200 --> 00:24:10,640 why we. 539 00:24:10,559 --> 00:24:13,240 Speaker 1: Can't see it because black holes don't emit or reflect 540 00:24:13,319 --> 00:24:13,799 any light. 541 00:24:13,920 --> 00:24:15,319 Speaker 2: It's the ultimate stealth object. 542 00:24:15,440 --> 00:24:16,559 Speaker 1: So could Ruben see that? 543 00:24:16,799 --> 00:24:20,839 Speaker 2: No, not directly. If this is true, the Ruben Observatory 544 00:24:20,839 --> 00:24:23,119 won't see it. You'd have to look for very subtle 545 00:24:23,119 --> 00:24:26,359 gravitational lensing events starlight bending around it as it passes 546 00:24:26,359 --> 00:24:28,319 in front. Would be a nightmare to find. 547 00:24:28,680 --> 00:24:32,519 Speaker 1: A fun nightmare though, and theory see. 548 00:24:32,599 --> 00:24:35,799 Speaker 2: The debris disc. This is the idea that instead of 549 00:24:35,799 --> 00:24:39,599 one big planet, it's a huge diffuse ring of millions 550 00:24:39,640 --> 00:24:43,440 of small icy rocks that all together collectively have the 551 00:24:43,440 --> 00:24:45,359 mass of ten earths. 552 00:24:45,039 --> 00:24:47,079 Speaker 1: So like a really heavy hula hoop at the edge 553 00:24:47,119 --> 00:24:48,480 of the Solar system pretty much. 554 00:24:49,000 --> 00:24:51,319 Speaker 2: But the main rebuttal there is heat. If you had 555 00:24:51,400 --> 00:24:53,680 that much dust and debris spread out over that much 556 00:24:53,680 --> 00:24:57,400 surface area, we would likely see the combined infrared glow 557 00:24:57,440 --> 00:25:00,640 from it. We don't see that. Also, use ring like 558 00:25:00,680 --> 00:25:03,880 that tends to be gravitationally unstable over billions of years. 559 00:25:04,200 --> 00:25:07,000 Speaker 1: So after weighing all the alternatives, planet nine is still 560 00:25:07,039 --> 00:25:07,720 the front runner. 561 00:25:07,920 --> 00:25:10,440 Speaker 2: It is still the simplest explanation that fits the most data, 562 00:25:10,839 --> 00:25:14,319 especially the orbital protection of those Neptune crossers. That five 563 00:25:14,359 --> 00:25:16,960 sigma result is very hard to explain with just modified 564 00:25:17,000 --> 00:25:20,400 gravity or a debris disc. Gravity from a single massive 565 00:25:20,480 --> 00:25:24,680 point source handles that shepherding resonance much more cleanly, So if. 566 00:25:24,599 --> 00:25:27,279 Speaker 1: It is there, this changes the map. We aren't just 567 00:25:27,319 --> 00:25:30,559 adding another dot to the chart. We are fundamentally redefining 568 00:25:30,599 --> 00:25:31,440 the Solar system. 569 00:25:31,599 --> 00:25:34,200 Speaker 2: We are proving the existence of what some astronomers are 570 00:25:34,200 --> 00:25:36,039 calling a third zone. 571 00:25:35,920 --> 00:25:38,200 Speaker 1: The third zone. I like the sound of that. What 572 00:25:38,240 --> 00:25:38,839 does that mean? 573 00:25:39,079 --> 00:25:41,519 Speaker 2: Well, we used to think the Solar system is pretty simple. 574 00:25:41,960 --> 00:25:44,920 You had Zone one, the inner rocky planets from Mercury 575 00:25:44,920 --> 00:25:47,680 to Mars. Then you had Zone two the gas and 576 00:25:47,759 --> 00:25:51,720 ized giants from Jupiter to Neptune and then the edge. 577 00:25:51,960 --> 00:25:54,079 Then we found the Kuiper Belt, which was sort of 578 00:25:54,119 --> 00:25:56,200 like the icy shoreline of the Solar. 579 00:25:55,920 --> 00:25:57,759 Speaker 1: System, and Planet nine changes that. 580 00:25:58,319 --> 00:26:02,640 Speaker 2: Planet nine implies a vast, deep third zone far beyond 581 00:26:02,680 --> 00:26:06,119 the giants, a region occupied by at least one massive 582 00:26:06,200 --> 00:26:09,519 world and maybe more. It tells us the Solar System 583 00:26:09,559 --> 00:26:11,920 doesn't just end it Neptune. It has a whole other chapter. 584 00:26:12,039 --> 00:26:14,799 Speaker 1: And this connects to the Nice model, right, the story 585 00:26:14,839 --> 00:26:17,000 of how our Solar system got here in the first place. 586 00:26:17,119 --> 00:26:19,680 Speaker 2: Exactly the Nice model, which is named after the city 587 00:26:19,680 --> 00:26:22,039 in France where it was developed, Not because it's just 588 00:26:22,079 --> 00:26:22,680 a nice. 589 00:26:22,480 --> 00:26:24,279 Speaker 1: Idea, although it is a nice idea. 590 00:26:24,359 --> 00:26:27,039 Speaker 2: It is a very nice idea. It describes the chaotic 591 00:26:27,240 --> 00:26:30,480 early days of the Solar System. The giant planets didn't 592 00:26:30,519 --> 00:26:33,519 form where they are now. They moved around, they migrated, 593 00:26:34,039 --> 00:26:37,640 and the simulation strongly suggest we didn't start with four giants. 594 00:26:37,920 --> 00:26:39,559 We likely started with five. 595 00:26:39,440 --> 00:26:40,319 Speaker 1: A lost sibling. 596 00:26:40,559 --> 00:26:46,039 Speaker 2: The lost sibling, the models showed Jupiter's immense gravity likely 597 00:26:46,079 --> 00:26:51,079 bullied this fifth giant planet, kicking it violently outward for 598 00:26:51,119 --> 00:26:53,319 a long time. The assumption was that it was ejected 599 00:26:53,319 --> 00:26:57,279 completely into interstellar space to become a rogue planet drifting 600 00:26:57,319 --> 00:26:58,519 alone between the stars. 601 00:26:58,799 --> 00:27:00,319 Speaker 1: But if Planet nine is the. 602 00:27:00,359 --> 00:27:02,359 Speaker 2: It's the one that got away but didn't actually leave. 603 00:27:02,440 --> 00:27:04,400 Speaker 1: It's just moved into the spare room exactly. 604 00:27:04,400 --> 00:27:06,119 Speaker 2: It didn't get kicked out of the house entirely. It 605 00:27:06,200 --> 00:27:08,720 just got pushed up into the attic. It's settled into 606 00:27:08,720 --> 00:27:14,240 this distant, lonely eccentric orbit. Finding it would be like 607 00:27:14,279 --> 00:27:16,880 finding a long lost brother of Jupiter and Neptune. 608 00:27:16,960 --> 00:27:19,079 Speaker 1: That is kind of poetic. It makes the Solar System 609 00:27:19,119 --> 00:27:21,519 feel like a family with the secret history we're just 610 00:27:21,559 --> 00:27:22,720 now uncovering, and it. 611 00:27:22,680 --> 00:27:25,640 Speaker 2: Confirms that our system is normal. If Plant nine is 612 00:27:25,640 --> 00:27:28,000 a super earth, we finally have the matching set. We 613 00:27:28,119 --> 00:27:29,680 finally fitted with the rest of the galaxy. 614 00:27:29,920 --> 00:27:32,039 Speaker 1: So where do we stand right now? We're in early 615 00:27:32,079 --> 00:27:34,599 twenty twenty six. What's the status. 616 00:27:34,640 --> 00:27:37,200 Speaker 2: We are in the final countdown. We're in the endgame. 617 00:27:37,759 --> 00:27:40,119 The search area in the sky has been narrowed down 618 00:27:40,160 --> 00:27:42,119 to less than ten percent of the predicted path. 619 00:27:42,240 --> 00:27:42,960 Speaker 1: That's huge. 620 00:27:43,240 --> 00:27:47,319 Speaker 2: The Ruben Observatory is scanning that very region night after night. 621 00:27:47,759 --> 00:27:50,920 The twenty twenty five archival candidate from the fan study 622 00:27:51,279 --> 00:27:53,359 is being rigorously re examined by. 623 00:27:53,279 --> 00:27:55,240 Speaker 1: Other teams, it really feels like we are right on 624 00:27:55,279 --> 00:27:57,039 the precipice of a major discovery. 625 00:27:57,599 --> 00:28:01,000 Speaker 2: I think detection is getting closer to being a logistical certainty. 626 00:28:01,599 --> 00:28:04,880 The conversation has shifted in the astronomical community. It's no 627 00:28:04,920 --> 00:28:08,279 longer is it there? It's where is it? And who 628 00:28:08,319 --> 00:28:09,440 is going to find it first? 629 00:28:09,759 --> 00:28:12,880 Speaker 1: And once we find it, what then? After the champagne 630 00:28:12,880 --> 00:28:14,519 and the headlines, what happens next? 631 00:28:14,720 --> 00:28:18,359 Speaker 2: We celebrate and then the real science begins. The moment 632 00:28:18,400 --> 00:28:21,240 we have a location, every major telescope on Earth will 633 00:28:21,279 --> 00:28:24,200 point at it. We can use spectroscopy to analyze the 634 00:28:24,240 --> 00:28:26,200 light coming from it, which will tell us what it's made. 635 00:28:26,079 --> 00:28:27,480 Speaker 1: Of, so we can know its composition. 636 00:28:27,759 --> 00:28:30,799 Speaker 2: Does it have a thick hydrogen atmosphere like Neptune? Is 637 00:28:30,839 --> 00:28:33,440 it a rocky world with a thin atmosphere? Does it 638 00:28:33,519 --> 00:28:36,759 have moons? We can start to answer those questions almost immediately. 639 00:28:36,839 --> 00:28:40,160 Speaker 1: Could we send a probe like Voyager or New Horizons? 640 00:28:40,359 --> 00:28:43,279 Speaker 2: We could, but you'd have to pack a lunch. It 641 00:28:43,319 --> 00:28:45,279 would take fifty years or more to get there with 642 00:28:45,319 --> 00:28:50,200 our current propulsion technology. But just knowing it's there it 643 00:28:50,240 --> 00:28:53,720 completes the picture. It changes how we view our place 644 00:28:53,720 --> 00:28:54,480 and the cosmos. 645 00:28:54,559 --> 00:28:57,079 Speaker 1: It's just incredible to think that right now, in twenty 646 00:28:57,119 --> 00:29:00,799 twenty six, we are still discovering may your pieces of 647 00:29:00,839 --> 00:29:02,319 geography in our own home. 648 00:29:02,680 --> 00:29:05,519 Speaker 2: Our home is bigger, weirder, and more crowded than we 649 00:29:05,599 --> 00:29:06,200 ever thought. 650 00:29:06,319 --> 00:29:08,559 Speaker 1: So here's the provocative thought I want to leave you 651 00:29:08,680 --> 00:29:12,960 the listener with. If Planet nine is a captured rogue planet, 652 00:29:13,519 --> 00:29:16,680 or if it's our solar system's lost sibling, what else 653 00:29:16,720 --> 00:29:18,519 is hiding out there in the third zone. 654 00:29:18,720 --> 00:29:21,640 Speaker 2: That's the question that keeps planetary scientists up at night. 655 00:29:21,960 --> 00:29:24,079 The universe rarely makes just one of anything. 656 00:29:24,160 --> 00:29:25,440 Speaker 1: Are we sure it's the only one? 657 00:29:25,839 --> 00:29:27,640 Speaker 2: Or is the darkness full of other ghosts we haven't 658 00:29:27,640 --> 00:29:28,240 even felt yet. 659 00:29:28,279 --> 00:29:30,119 Speaker 1: I love that, and I want to ask you directly 660 00:29:30,240 --> 00:29:32,359 if we find it, When we find it, what should 661 00:29:32,359 --> 00:29:34,759 we name it? The tradition is Roman and Greek gods. 662 00:29:34,799 --> 00:29:39,079 Who's left? Or do you prefer the grapefruit sized black 663 00:29:39,119 --> 00:29:42,200 hole theory? Because that is a movie waiting to happen. 664 00:29:42,519 --> 00:29:44,440 Speaker 2: I'm personally rooting for the planet. I want to see 665 00:29:44,480 --> 00:29:46,400 the picture on add it to the family portrait. 666 00:29:46,640 --> 00:29:48,880 Speaker 1: Me too. Let us know what you think in the 667 00:29:48,880 --> 00:29:52,920 comments below. This has been thrilling threads. Thanks for listening 668 00:29:52,920 --> 00:29:56,079 to us unravel the universe, Keep looking up, see next time.