1
00:00:08,480 --> 00:00:10,680
Speaker 1: Hey, Daniel, what pets do you have these days?

2
00:00:10,800 --> 00:00:13,119
Speaker 2: Oh, we just have our rescue dog, Peppito.

3
00:00:14,080 --> 00:00:16,680
Speaker 1: Haven't you had other pets in the past, like rodents.

4
00:00:17,680 --> 00:00:19,680
Speaker 2: We did have rats for a time, and we actually

5
00:00:19,680 --> 00:00:20,800
Speaker 2: had cats before that.

6
00:00:21,320 --> 00:00:23,680
Speaker 1: Oh what happened Pepito?

7
00:00:23,880 --> 00:00:29,040
Speaker 2: Ate them? No, we've never had a pet eat another pet.

8
00:00:29,080 --> 00:00:30,520
Speaker 2: We've only lost them to old age.

9
00:00:30,840 --> 00:00:33,240
Speaker 1: Old age. All that dark chocolate and big goods in

10
00:00:33,280 --> 00:00:35,520
Speaker 1: your house just did them in with the heart attack.

11
00:00:37,440 --> 00:00:40,320
Speaker 2: We don't feed dark chocolate at the dog, but everybody

12
00:00:40,360 --> 00:00:42,200
Speaker 2: does eat pretty well at our house.

13
00:00:42,800 --> 00:00:44,680
Speaker 1: Unless you like white chocolate, then your starved.

14
00:00:44,840 --> 00:00:46,560
Speaker 2: You know. If that's the reason you run away from home,

15
00:00:46,640 --> 00:00:48,479
Speaker 2: then maybe you never were really a white sun.

16
00:00:48,640 --> 00:00:50,440
Speaker 1: Wait, if you don't like white chocolate, you're not a

17
00:00:50,479 --> 00:00:53,520
Speaker 1: white son. It sounds like a white lie.

18
00:00:53,720 --> 00:01:10,280
Speaker 2: I have a dark secret. Hi.

19
00:01:10,280 --> 00:01:12,560
Speaker 1: I am Poor hammy cartoonists and the author of Oliver's

20
00:01:12,600 --> 00:01:13,600
Speaker 1: Great Big Universe.

21
00:01:13,880 --> 00:01:17,119
Speaker 2: Hi. I'm Daniel. I'm a particle physicist and a professor

22
00:01:17,200 --> 00:01:20,280
Speaker 2: at UC Irvine, and I will not waiver in my

23
00:01:20,400 --> 00:01:21,440
Speaker 2: campaign for dark.

24
00:01:21,319 --> 00:01:25,520
Speaker 1: Chocolate, Dark chocolate, dark matter. You're just a very dark physicist.

25
00:01:27,720 --> 00:01:29,440
Speaker 2: I'm trying to bring light to the world at the

26
00:01:29,480 --> 00:01:32,319
Speaker 2: same time as exposed all the dark secrets of the universe.

27
00:01:32,680 --> 00:01:35,679
Speaker 1: Oh, you're trying to expose dark matter. I thought you

28
00:01:35,720 --> 00:01:37,600
Speaker 1: were all about letting the universe.

29
00:01:37,240 --> 00:01:40,560
Speaker 2: Be Absolutely not. I do not believe in universe privacy.

30
00:01:40,680 --> 00:01:42,080
Speaker 1: You're like the universe paparazzi.

31
00:01:42,959 --> 00:01:45,080
Speaker 2: That's exactly right, except I'm not selling it to the

32
00:01:45,160 --> 00:01:47,520
Speaker 2: national inquirer. I'm just publishing papers.

33
00:01:47,720 --> 00:01:52,520
Speaker 1: Well, your buyer is the cosmological inquirer, the human inquirer.

34
00:01:55,120 --> 00:01:56,680
Speaker 2: Inquiring brains want to know.

35
00:01:57,160 --> 00:01:59,360
Speaker 1: Yeah, do you stand outside their home, like, Hey, dark

36
00:01:59,400 --> 00:02:02,640
Speaker 1: matter over here, over here snapping pictures?

37
00:02:03,040 --> 00:02:05,240
Speaker 2: If I knew where dark matter lived, I would definitely

38
00:02:05,280 --> 00:02:06,800
Speaker 2: go there with my dark matter camera.

39
00:02:06,840 --> 00:02:09,040
Speaker 1: I thought dark matter was all around us. It lives

40
00:02:09,080 --> 00:02:13,079
Speaker 1: in us and within us. It surrounds us and binds

41
00:02:13,080 --> 00:02:13,919
Speaker 1: the galaxy together.

42
00:02:14,160 --> 00:02:16,720
Speaker 2: You're absolutely right, it's everywhere. We just don't know how

43
00:02:16,800 --> 00:02:17,680
Speaker 2: to take a picture of it.

44
00:02:17,919 --> 00:02:20,400
Speaker 1: But anyways, welcome to our podcast, Daniel and Jorge Explain

45
00:02:20,480 --> 00:02:23,240
Speaker 1: the Universe, a production of iHeartRadio.

46
00:02:22,639 --> 00:02:25,800
Speaker 2: In which we join our inquiring minds with yours to

47
00:02:25,960 --> 00:02:29,280
Speaker 2: wonder together about the nature of the universe, to think

48
00:02:29,320 --> 00:02:33,040
Speaker 2: deeply about how everything comes together to make the cosmos

49
00:02:33,040 --> 00:02:35,639
Speaker 2: and the night sky that we appreciate to think about

50
00:02:35,639 --> 00:02:38,880
Speaker 2: how the tiniest little particles and the most massive black

51
00:02:38,880 --> 00:02:41,919
Speaker 2: holes shape the very world we live in, and whether

52
00:02:42,040 --> 00:02:43,600
Speaker 2: it has always looked this way.

53
00:02:43,680 --> 00:02:46,280
Speaker 1: That's right. We satisfy our curiosity for stars and what

54
00:02:46,320 --> 00:02:48,600
Speaker 1: they're doing with their lives, and we take pictures and

55
00:02:48,680 --> 00:02:51,760
Speaker 1: also sound recordings of what's out there in the universe

56
00:02:51,800 --> 00:02:54,239
Speaker 1: and what's going on to maybe get a clue about

57
00:02:54,280 --> 00:02:55,280
Speaker 1: how it all works.

58
00:02:55,360 --> 00:02:57,639
Speaker 2: We'd like to figure out the fundamental nature of the

59
00:02:57,720 --> 00:03:00,680
Speaker 2: universal laws that everything follows. But I also like to

60
00:03:00,720 --> 00:03:04,200
Speaker 2: know the story of the universe. What happened, How did

61
00:03:04,280 --> 00:03:07,200
Speaker 2: we end up where we are? How long have things

62
00:03:07,280 --> 00:03:09,640
Speaker 2: looked this way for? How long can we rely on

63
00:03:09,720 --> 00:03:11,960
Speaker 2: things to look this way? Do we live in a

64
00:03:12,000 --> 00:03:14,560
Speaker 2: momentary blip of the universe or is this a long

65
00:03:14,680 --> 00:03:15,360
Speaker 2: term trend?

66
00:03:15,639 --> 00:03:17,760
Speaker 1: Yeah, looking at our past is a way to look

67
00:03:17,800 --> 00:03:19,960
Speaker 1: into our future. We can try to deduce. But the

68
00:03:20,040 --> 00:03:22,280
Speaker 1: rules of the universe are and what they might mean

69
00:03:22,320 --> 00:03:24,320
Speaker 1: for us in the deep future? What is going to

70
00:03:24,360 --> 00:03:26,720
Speaker 1: be the future of humanity here in our solar system?

71
00:03:26,840 --> 00:03:29,040
Speaker 1: Can we call this our home for the next few

72
00:03:29,040 --> 00:03:29,680
Speaker 1: billion years?

73
00:03:31,480 --> 00:03:32,919
Speaker 2: Are you not planning to move out of that house

74
00:03:32,919 --> 00:03:34,800
Speaker 2: for a few billion years, so your kids can always

75
00:03:34,800 --> 00:03:36,840
Speaker 2: come home and their kids and their kids and their kids.

76
00:03:36,880 --> 00:03:38,880
Speaker 1: Well, we're kind of just squatting in this solar system,

77
00:03:38,960 --> 00:03:41,280
Speaker 1: right like we just popped in here, started living here.

78
00:03:41,640 --> 00:03:44,920
Speaker 1: We didn't ask if anyone owned these planets. What if

79
00:03:44,960 --> 00:03:46,760
Speaker 1: the real owners come back when they they're like, what

80
00:03:46,960 --> 00:03:49,400
Speaker 1: is going on here? Call pest control.

81
00:03:50,440 --> 00:03:52,200
Speaker 2: Don't we have some sort of like solar B and

82
00:03:52,200 --> 00:03:57,520
Speaker 2: B contract squatter rights. Maybe exactly after one hundred million years,

83
00:03:57,560 --> 00:04:00,200
Speaker 2: we're officially allowed to call ourselves the owners. It's a

84
00:04:00,200 --> 00:04:02,800
Speaker 2: good question how long things have looked this way. When

85
00:04:02,840 --> 00:04:04,640
Speaker 2: you look by the night guy, you expect to see

86
00:04:04,680 --> 00:04:07,120
Speaker 2: basically the same stars as you did a year ago,

87
00:04:07,240 --> 00:04:09,440
Speaker 2: and you know that you're looking at roughly the same

88
00:04:09,520 --> 00:04:12,600
Speaker 2: stars that Newton looked at, and the Egyptians looked at

89
00:04:12,640 --> 00:04:15,880
Speaker 2: and the Sumerians looked at thousands of years ago. But

90
00:04:15,960 --> 00:04:18,320
Speaker 2: the Solar system operates on a very different kind of

91
00:04:18,360 --> 00:04:21,919
Speaker 2: timescale than your life or even human civilization. And in

92
00:04:22,000 --> 00:04:24,720
Speaker 2: fast forward things don't seem so stable. They seem quite

93
00:04:24,839 --> 00:04:26,240
Speaker 2: chaotic and dynamic.

94
00:04:26,600 --> 00:04:28,359
Speaker 1: Yeah, when we were all kids, we learned in school

95
00:04:28,360 --> 00:04:30,400
Speaker 1: about the different planets in our solar system and how

96
00:04:30,440 --> 00:04:33,279
Speaker 1: many of there are. And that's basically the same story

97
00:04:33,279 --> 00:04:35,520
Speaker 1: that our kids are learning in school as well, right, Like,

98
00:04:35,560 --> 00:04:38,000
Speaker 1: it hasn't really changed so much, except maybe for Pluto.

99
00:04:39,320 --> 00:04:41,800
Speaker 2: We of course change what we mean by a planet

100
00:04:42,080 --> 00:04:45,120
Speaker 2: and make up new categories all the time. But you're right,

101
00:04:45,160 --> 00:04:48,120
Speaker 2: the stuff that's out there that we're seeing, whatever name

102
00:04:48,160 --> 00:04:51,120
Speaker 2: we give it, hasn't changed in our lifetime or in

103
00:04:51,160 --> 00:04:52,560
Speaker 2: our grandparents' lifetime.

104
00:04:52,760 --> 00:04:54,000
Speaker 1: Yeah, And so I guess you kind of get the

105
00:04:54,080 --> 00:04:56,839
Speaker 1: sense that maybe it will never change, you know, you

106
00:04:56,920 --> 00:04:59,599
Speaker 1: sort of memorize these facts and these things and think

107
00:04:59,600 --> 00:05:02,040
Speaker 1: that maybe it's going to be like that forever. But actually,

108
00:05:02,160 --> 00:05:04,040
Speaker 1: if you look at the grand scale of the Solar

109
00:05:04,040 --> 00:05:07,279
Speaker 1: System and the universe in or galaxy, things are rapidly changing.

110
00:05:07,320 --> 00:05:08,800
Speaker 1: If you look at it from that point of view.

111
00:05:08,839 --> 00:05:10,600
Speaker 2: If the Solar system changes, do you think we all

112
00:05:10,600 --> 00:05:12,440
Speaker 2: have to go back to elementary school to learn a

113
00:05:12,440 --> 00:05:13,040
Speaker 2: new mnemonic?

114
00:05:13,200 --> 00:05:15,240
Speaker 1: Oh, there's a mnemonic. I didn't grow up yours. I

115
00:05:15,279 --> 00:05:21,040
Speaker 1: don't know what do you use? Obviously the mnemonic did

116
00:05:21,080 --> 00:05:22,200
Speaker 1: it work because you don't remember it.

117
00:05:24,000 --> 00:05:26,000
Speaker 2: There's a lot of mnemonics to help you memorize the

118
00:05:26,080 --> 00:05:29,320
Speaker 2: order of the planets. One of them is my very

119
00:05:29,440 --> 00:05:36,720
Speaker 2: easy method just speeds up nothing. Mercury, Venus, Earth, Mars, Jupiter, Saturn, Urinus, Neptune.

120
00:05:36,880 --> 00:05:40,159
Speaker 1: Whoa, that is so not kit friendly. How many kids

121
00:05:40,320 --> 00:05:42,120
Speaker 1: use methods and have methods?

122
00:05:42,200 --> 00:05:44,080
Speaker 2: The history of them is actually really funny. There's ones

123
00:05:44,080 --> 00:05:47,719
Speaker 2: from the fifties that go like men very easily make jugs,

124
00:05:47,800 --> 00:05:48,719
Speaker 2: serve useful needs.

125
00:05:48,720 --> 00:05:52,440
Speaker 1: Perhaps, Oh man, I wonder why we'd stopped using that one.

126
00:05:52,920 --> 00:05:55,760
Speaker 2: And then a more recent one says, my very energetic

127
00:05:55,760 --> 00:05:58,159
Speaker 2: mother jumps skateboards under nana's patio.

128
00:05:58,320 --> 00:06:00,159
Speaker 1: Oh, there you go. That's a pretty good one, and

129
00:06:00,279 --> 00:06:01,919
Speaker 1: true as well for some people.

130
00:06:01,920 --> 00:06:05,719
Speaker 2: I'm sure my very educated mother just served us notches.

131
00:06:06,040 --> 00:06:07,560
Speaker 1: Oh that's an even tastier.

132
00:06:07,160 --> 00:06:11,320
Speaker 2: One, exactly. But the point is that though these things

133
00:06:11,360 --> 00:06:14,599
Speaker 2: have seemed stable for a long time, it's not necessarily

134
00:06:14,640 --> 00:06:16,200
Speaker 2: true that they always will be.

135
00:06:16,360 --> 00:06:18,400
Speaker 1: Yeah, things are always changing, And in fact, you can

136
00:06:18,440 --> 00:06:21,640
Speaker 1: ask the question of whether our solar SYSM had more

137
00:06:21,720 --> 00:06:22,920
Speaker 1: planets in the past.

138
00:06:23,160 --> 00:06:25,640
Speaker 2: It might be that the planets we know today are

139
00:06:25,720 --> 00:06:29,120
Speaker 2: not all the planets that have ever orbited our star.

140
00:06:29,240 --> 00:06:31,760
Speaker 1: And if we had more, what happened to them? So

141
00:06:31,839 --> 00:06:39,159
Speaker 1: today on the podcast will be tackling the question has

142
00:06:39,240 --> 00:06:43,480
Speaker 1: our Solar System lost any planets? That just seems kind

143
00:06:43,480 --> 00:06:45,880
Speaker 1: of irresponsible there. How can you lose a whole planet?

144
00:06:47,320 --> 00:06:49,000
Speaker 2: I mean I had it in my hands and then

145
00:06:49,040 --> 00:06:51,480
Speaker 2: I put my keys down and the last place.

146
00:06:51,440 --> 00:06:54,240
Speaker 1: Remember having that planet was on top of the dog.

147
00:06:56,000 --> 00:06:57,840
Speaker 2: Blamed the dog. Huh, that's the first thing.

148
00:06:58,640 --> 00:07:01,360
Speaker 1: The dog ate my planet. Classic excuse.

149
00:07:02,040 --> 00:07:04,600
Speaker 2: Or maybe it just went rogue because it needed to

150
00:07:04,640 --> 00:07:07,440
Speaker 2: find a white chocolate friendly Solar system. You know, maybe

151
00:07:07,480 --> 00:07:08,520
Speaker 2: it just didn't fit in here.

152
00:07:09,000 --> 00:07:12,640
Speaker 1: It just rebelled against your tyranny of trying to dictate

153
00:07:12,680 --> 00:07:14,680
Speaker 1: what kind of chocolate people should eat or feel good

154
00:07:14,720 --> 00:07:16,360
Speaker 1: about eating. Doctor, Why.

155
00:07:17,960 --> 00:07:20,760
Speaker 2: You call it tyranny, I call it wisdom. Let's call

156
00:07:20,760 --> 00:07:21,480
Speaker 2: the whole thing off.

157
00:07:22,080 --> 00:07:25,440
Speaker 1: Yeah, that's what I'll tyrn say at two. Yeah, So

158
00:07:25,480 --> 00:07:28,040
Speaker 1: it's been an interesting story of the Solar System. You

159
00:07:28,120 --> 00:07:30,080
Speaker 1: got to wonder if maybef we had more than nine

160
00:07:30,160 --> 00:07:32,320
Speaker 1: or eight planets in the past. Well, we definitely had

161
00:07:32,320 --> 00:07:34,840
Speaker 1: more planets to pay in the past before Pluto got downgraded.

162
00:07:34,880 --> 00:07:37,160
Speaker 1: But that's a separate story and a separate reason.

163
00:07:37,240 --> 00:07:37,400
Speaker 3: Right.

164
00:07:37,520 --> 00:07:39,960
Speaker 2: Yeah, Pluto is still there, it's just not called the

165
00:07:40,000 --> 00:07:42,400
Speaker 2: planet anymore. It's called a dwarf planet.

166
00:07:42,200 --> 00:07:44,720
Speaker 1: Right, But we can ask the question of whether our

167
00:07:44,720 --> 00:07:48,360
Speaker 1: solar system did really have other giant planets like Jupiter

168
00:07:48,480 --> 00:07:51,280
Speaker 1: or Mars or Venus, but maybe they decided they didn't

169
00:07:51,320 --> 00:07:51,720
Speaker 1: like it here.

170
00:07:51,760 --> 00:07:53,560
Speaker 2: It's really fun to dig into the history of the

171
00:07:53,600 --> 00:07:56,280
Speaker 2: Solar system and understand how we got here, how it

172
00:07:56,360 --> 00:07:58,360
Speaker 2: might have been different, and give us a sense for

173
00:07:58,440 --> 00:08:01,560
Speaker 2: what other solar systems out there are likely to look like.

174
00:08:01,720 --> 00:08:03,640
Speaker 1: So, as usual, we were wondering how many people had

175
00:08:03,680 --> 00:08:07,040
Speaker 1: thought about the question of whether our solar system lost

176
00:08:07,120 --> 00:08:10,800
Speaker 1: any planets, or at least misplaced them temporarily. Maybe, So,

177
00:08:10,840 --> 00:08:12,720
Speaker 1: as usual, Daniel went out there into the internet to

178
00:08:12,720 --> 00:08:16,560
Speaker 1: ask people has our Solar system lost any planets?

179
00:08:16,720 --> 00:08:19,280
Speaker 2: Thanks very much to our group of volunteers. We greatly

180
00:08:19,280 --> 00:08:21,640
Speaker 2: appreciate them, but we also would like to add you

181
00:08:21,760 --> 00:08:24,400
Speaker 2: to their ranks. Please don't be shy write to me

182
00:08:24,480 --> 00:08:27,400
Speaker 2: two questions at Danielanjorge dot com.

183
00:08:27,440 --> 00:08:29,160
Speaker 1: What do people get I know if they sign up.

184
00:08:29,160 --> 00:08:32,240
Speaker 2: The satisfaction of hearing their voice on the podcast and

185
00:08:32,480 --> 00:08:35,960
Speaker 2: a weekly injection of hard physics questions.

186
00:08:35,640 --> 00:08:38,240
Speaker 1: And also a monthly supply of white chocolate that gets

187
00:08:38,320 --> 00:08:39,120
Speaker 1: kicked out of your house.

188
00:08:39,280 --> 00:08:41,959
Speaker 2: I will send you exactly zero grams of white chocolate.

189
00:08:44,480 --> 00:08:46,480
Speaker 1: Well, think about it for a second. Do you think

190
00:08:46,520 --> 00:08:50,160
Speaker 1: our Solar System has lost any planets? Here's what people

191
00:08:50,160 --> 00:08:50,600
Speaker 1: had to say.

192
00:08:50,880 --> 00:08:52,760
Speaker 3: I don't know if we can know for sure, maybe

193
00:08:52,760 --> 00:08:55,079
Speaker 3: by the orbits of current planets, but I'd have to

194
00:08:55,120 --> 00:08:57,520
Speaker 3: assume given the five billion years or so that or

195
00:08:57,520 --> 00:08:59,360
Speaker 3: some spent around, that at least one planet has come

196
00:08:59,400 --> 00:09:02,160
Speaker 3: in and been kicked out. But maybe it depends on

197
00:09:02,200 --> 00:09:04,240
Speaker 3: if we consider those objects planets.

198
00:09:04,360 --> 00:09:07,480
Speaker 4: So I think that there have been planets knocked out

199
00:09:07,480 --> 00:09:10,560
Speaker 4: of the Solar System, especially since when the Solar System

200
00:09:10,640 --> 00:09:13,160
Speaker 4: was first created there would have been loads of rocks

201
00:09:13,160 --> 00:09:16,360
Speaker 4: flying around to form planets. So then there would have

202
00:09:16,360 --> 00:09:19,360
Speaker 4: been planets formed and then hit by maybe another planet

203
00:09:19,360 --> 00:09:20,720
Speaker 4: which knocked them out of the system.

204
00:09:20,880 --> 00:09:23,240
Speaker 5: Nothing that I know of, they're all accounted for. Some

205
00:09:23,280 --> 00:09:26,480
Speaker 5: of them have lost the designation planet, like Pluto. I

206
00:09:26,480 --> 00:09:31,160
Speaker 5: think regularly objects get flung out of Solar systems due

207
00:09:31,200 --> 00:09:32,559
Speaker 5: to gravitational interactions with.

208
00:09:32,559 --> 00:09:33,400
Speaker 2: Other own jobjects.

209
00:09:33,400 --> 00:09:36,959
Speaker 5: So I can imagine Jupiter getting tired of somesome little

210
00:09:37,000 --> 00:09:39,760
Speaker 5: planet and flinging it out. Maybe when we were forming

211
00:09:39,840 --> 00:09:41,920
Speaker 5: all the planets performing them. Some of them were close

212
00:09:41,920 --> 00:09:43,760
Speaker 5: to the Sun and got gabbled up. I'm curious to

213
00:09:43,800 --> 00:09:46,640
Speaker 5: know if there's any record of planets that we're here

214
00:09:46,679 --> 00:09:47,480
Speaker 5: in now or not.

215
00:09:47,720 --> 00:09:51,160
Speaker 6: Apart from the reclassification of Pluto as a dwarf planet,

216
00:09:51,240 --> 00:09:54,559
Speaker 6: meaning that we've effectively lost one planet, I have heard

217
00:09:54,640 --> 00:09:57,319
Speaker 6: rumors about a tenth planet, which would now be a

218
00:09:57,400 --> 00:10:01,400
Speaker 6: ninth planet, that potentially all within our inn a soda

219
00:10:01,400 --> 00:10:04,040
Speaker 6: system and then could have collided with Earth and created

220
00:10:04,080 --> 00:10:07,439
Speaker 6: the Moon and then spun off out into an orbit

221
00:10:07,679 --> 00:10:10,640
Speaker 6: way out in our outer Soder system. Other than that,

222
00:10:10,760 --> 00:10:12,280
Speaker 6: I'm unaware of any lost planets.

223
00:10:12,360 --> 00:10:15,440
Speaker 1: Interesting answers. It seems to be all over the place.

224
00:10:15,480 --> 00:10:17,920
Speaker 1: Some people say yes, some people say no, not really,

225
00:10:17,960 --> 00:10:19,400
Speaker 1: some people say poor Pluto.

226
00:10:21,280 --> 00:10:23,920
Speaker 2: There does generally seem to be an appreciation of the

227
00:10:23,960 --> 00:10:26,920
Speaker 2: fact that the Solar System might not have always been

228
00:10:27,040 --> 00:10:31,520
Speaker 2: an orderly, stately placed that there might have been primordial chaos.

229
00:10:31,720 --> 00:10:33,200
Speaker 1: That's right. It was a big party here in the

230
00:10:33,280 --> 00:10:35,480
Speaker 1: Solar System, where we're kind of in the after party

231
00:10:35,520 --> 00:10:36,760
Speaker 1: of the Solar System, right.

232
00:10:37,360 --> 00:10:40,280
Speaker 2: We're waking up the next morning going, man, what happened?

233
00:10:40,280 --> 00:10:42,120
Speaker 2: And has anybody seen a dog?

234
00:10:43,360 --> 00:10:46,400
Speaker 1: Yeah? Well, why am I waking up next to Venus here?

235
00:10:46,760 --> 00:10:47,520
Speaker 1: How did that happen?

236
00:10:47,640 --> 00:10:49,720
Speaker 2: And why is the hot tub filled with white chocolate?

237
00:10:50,280 --> 00:10:54,520
Speaker 1: Yeah, so let's start with the basics, Daniel, is it

238
00:10:54,559 --> 00:10:58,320
Speaker 1: even possible for Solar system to lose the planet? I

239
00:10:58,360 --> 00:11:01,520
Speaker 1: thought that, you know, once you form, things are kind

240
00:11:01,520 --> 00:11:05,000
Speaker 1: of stuck to you gravitationally in orbits, or that at

241
00:11:05,080 --> 00:11:07,920
Speaker 1: least that it's hard to escape the gravitational field of

242
00:11:08,040 --> 00:11:11,640
Speaker 1: like Sun or all these planets. Wouldn't they either fall

243
00:11:11,640 --> 00:11:13,280
Speaker 1: in or go into a stable orbit.

244
00:11:13,360 --> 00:11:16,000
Speaker 2: I think the key idea is the word you used, form, Like,

245
00:11:16,160 --> 00:11:19,640
Speaker 2: when do you consider the Solar System to have formed?

246
00:11:20,040 --> 00:11:24,080
Speaker 2: The Solar system? Formation is a slow and gradual, constant process.

247
00:11:24,120 --> 00:11:27,440
Speaker 2: It's basically always changing. And so you can go all

248
00:11:27,480 --> 00:11:29,680
Speaker 2: the way back to the very beginning of the Solar

249
00:11:29,679 --> 00:11:33,840
Speaker 2: system to understand the chaos of that formation and understand

250
00:11:33,840 --> 00:11:36,880
Speaker 2: that that formation is a constant process, that things are

251
00:11:37,040 --> 00:11:39,880
Speaker 2: always potentially bumping into each other and disturbing each other.

252
00:11:40,040 --> 00:11:42,320
Speaker 1: Wait, are you saying that if we leave the window

253
00:11:42,440 --> 00:11:44,640
Speaker 1: open for the fact that maybe the Solar System is

254
00:11:44,640 --> 00:11:48,000
Speaker 1: still forming, does that mean we technically haven't lost any planets? Like?

255
00:11:48,080 --> 00:11:50,480
Speaker 1: Can I use it in my real life.

256
00:11:51,320 --> 00:11:54,040
Speaker 2: No, it just means that during the formation, planets could

257
00:11:54,120 --> 00:11:57,280
Speaker 2: form and be lost. There is no final form to

258
00:11:57,320 --> 00:12:00,360
Speaker 2: the Solar System. It's a constantly evolving thing. It's not

259
00:12:00,400 --> 00:12:02,760
Speaker 2: like at some point somebody says, Okay, the Solar System

260
00:12:02,840 --> 00:12:05,240
Speaker 2: is finished, let's package it and ship it and move

261
00:12:05,280 --> 00:12:06,880
Speaker 2: on to the next project. I see.

262
00:12:06,920 --> 00:12:09,960
Speaker 1: It's like a Pokemon, is what you're saying. It's always evolving,

263
00:12:10,240 --> 00:12:11,640
Speaker 1: it's looking for its final form.

264
00:12:12,000 --> 00:12:13,920
Speaker 2: I don't know enough about Pokemon to know whether that

265
00:12:13,960 --> 00:12:15,600
Speaker 2: analogy holds, So I'm just gonna.

266
00:12:15,400 --> 00:12:18,160
Speaker 1: Trust you on that. I don't know either. To be honest,

267
00:12:19,320 --> 00:12:21,000
Speaker 1: I just heard final form and it made me think

268
00:12:21,040 --> 00:12:21,600
Speaker 1: of Pokemon.

269
00:12:21,720 --> 00:12:23,560
Speaker 2: Well, it's sort of in the same way that animals

270
00:12:23,559 --> 00:12:26,480
Speaker 2: never have a final form. Evolution is a constant process.

271
00:12:26,720 --> 00:12:29,760
Speaker 2: Things are always changing in response to the environment.

272
00:12:30,400 --> 00:12:33,240
Speaker 1: Except for crocodiles and sharks, they're pretty settled there.

273
00:12:33,080 --> 00:12:34,800
Speaker 2: In the plateau. Yeah that's true.

274
00:12:35,000 --> 00:12:37,480
Speaker 1: Yeah, but let me take us through to some of

275
00:12:37,480 --> 00:12:39,360
Speaker 1: the early history of the Solar System. How do we

276
00:12:39,400 --> 00:12:40,679
Speaker 1: get planets in the first place.

277
00:12:40,800 --> 00:12:43,920
Speaker 2: So planetary formation is a super fascinating topic, and it

278
00:12:43,960 --> 00:12:46,560
Speaker 2: helps us understand like the formation of the Solar System

279
00:12:46,600 --> 00:12:49,360
Speaker 2: as a whole. Remember that the Solar system forms from

280
00:12:49,360 --> 00:12:52,680
Speaker 2: the collapse of a huge cloud of like gas and dust.

281
00:12:53,000 --> 00:12:55,240
Speaker 2: It's mostly hydrogen, which is made in the Big Bang,

282
00:12:55,559 --> 00:12:57,960
Speaker 2: and it's also interspersed with a bunch of other heavier

283
00:12:58,000 --> 00:13:01,000
Speaker 2: stuff that's made from other solarss where the stars have

284
00:13:01,040 --> 00:13:04,200
Speaker 2: already fused heavier elements out of that hydrogen. So you

285
00:13:04,200 --> 00:13:06,320
Speaker 2: have this big cloud of mostly hydrogen with a few

286
00:13:06,320 --> 00:13:09,400
Speaker 2: heavier bits in it, and it collapses into stars. You

287
00:13:09,400 --> 00:13:11,720
Speaker 2: don't just get one solar system. You typically get several

288
00:13:11,720 --> 00:13:14,280
Speaker 2: made at the same time. In one of these stellar nurseries,

289
00:13:14,600 --> 00:13:16,040
Speaker 2: we have a big blob of this stuff and it

290
00:13:16,080 --> 00:13:18,520
Speaker 2: collapses and most of the stuff goes into the center

291
00:13:18,840 --> 00:13:20,920
Speaker 2: to make a star, like ninety nine percent of the

292
00:13:20,960 --> 00:13:23,800
Speaker 2: stuff goes in to make the star. But you typically

293
00:13:23,840 --> 00:13:27,000
Speaker 2: have a disc of gas and dust that's orbiting that star.

294
00:13:27,440 --> 00:13:29,640
Speaker 2: It's spinning too fast to collapse in the way the

295
00:13:29,679 --> 00:13:32,880
Speaker 2: Moon is orbiting the Earth without falling into the Earth,

296
00:13:33,320 --> 00:13:37,520
Speaker 2: and so you get this protoplanetary disc around this new star,

297
00:13:38,240 --> 00:13:42,120
Speaker 2: and that disc then coalesces into larger stuff. Gravity is

298
00:13:42,200 --> 00:13:44,440
Speaker 2: doing the work there to pull the gas and dust

299
00:13:44,559 --> 00:13:47,360
Speaker 2: in the disk into heavier things. And where you have

300
00:13:47,520 --> 00:13:50,960
Speaker 2: like little spots of iron or little spots of heavier metals,

301
00:13:51,000 --> 00:13:54,120
Speaker 2: those things will use their gravity to form larger objects.

302
00:13:54,840 --> 00:13:57,840
Speaker 1: But I think the Solar System formed into a disc first,

303
00:13:57,920 --> 00:13:59,520
Speaker 1: and then the star kind of ignited.

304
00:13:59,600 --> 00:14:02,040
Speaker 2: Right. Moment of ignition depends a little bit on the

305
00:14:02,040 --> 00:14:03,760
Speaker 2: mass of the star. I mean, in some cases you

306
00:14:03,760 --> 00:14:06,280
Speaker 2: don't even get ignition if there isn't enough mass there.

307
00:14:06,320 --> 00:14:09,120
Speaker 2: You have like a subcritical brown dwarf, but it's definitely

308
00:14:09,160 --> 00:14:11,680
Speaker 2: collapsing into a disc as it forms. Right, a big

309
00:14:11,679 --> 00:14:13,920
Speaker 2: amorphous blob is going to collapse, and it's going to

310
00:14:13,960 --> 00:14:16,560
Speaker 2: collapse into a disc shape because of its angular rotation.

311
00:14:17,120 --> 00:14:19,400
Speaker 2: So the two things can sort of happen simultaneously, And

312
00:14:19,440 --> 00:14:22,160
Speaker 2: when ignition happens depends on the mass of the star.

313
00:14:22,440 --> 00:14:24,880
Speaker 1: Right, And there's also kind of an intermediate step there

314
00:14:24,880 --> 00:14:28,680
Speaker 1: where the disc kind of turns into rings for a while.

315
00:14:28,720 --> 00:14:30,840
Speaker 1: Right before you get the planets.

316
00:14:30,520 --> 00:14:33,000
Speaker 2: Exactly, you get the seeding of structure and they pull

317
00:14:33,120 --> 00:14:36,960
Speaker 2: together into larger and larger objects, and rings are basically

318
00:14:37,000 --> 00:14:40,800
Speaker 2: just clusters of larger objects. So you get these gaps emerging,

319
00:14:41,200 --> 00:14:44,040
Speaker 2: and then you get those things formed together into planets

320
00:14:44,160 --> 00:14:47,720
Speaker 2: or not, depending on the tidal forces. A large object

321
00:14:47,760 --> 00:14:49,440
Speaker 2: can form and sort of gather up a lot of

322
00:14:49,440 --> 00:14:51,280
Speaker 2: the gas and dust near it, and then it can

323
00:14:51,320 --> 00:14:54,640
Speaker 2: also distort the other stuff nearby, preventing it from forming.

324
00:14:54,760 --> 00:14:57,080
Speaker 2: So it's a bit of a chaotic process in the beginning,

325
00:14:57,520 --> 00:14:59,480
Speaker 2: and it also depends a little bit on your distance

326
00:14:59,520 --> 00:15:02,040
Speaker 2: from the st There's a point it's called the snow line,

327
00:15:02,120 --> 00:15:04,800
Speaker 2: after which water tends to be ice, tends to be

328
00:15:04,840 --> 00:15:07,360
Speaker 2: a solid, and before which it tends to be vapor.

329
00:15:07,480 --> 00:15:09,760
Speaker 2: Like if you're close enough to the star, it's warm

330
00:15:09,840 --> 00:15:11,960
Speaker 2: enough that the water is vapor and if you're further

331
00:15:11,960 --> 00:15:14,960
Speaker 2: from that point, the water is frozen. That helps form

332
00:15:15,040 --> 00:15:18,080
Speaker 2: giant planets. So you tend to have these large planets

333
00:15:18,120 --> 00:15:21,080
Speaker 2: with ice and rock seeding structure on the outer part

334
00:15:21,120 --> 00:15:23,000
Speaker 2: of the Solar System past the snow line, and then

335
00:15:23,120 --> 00:15:26,040
Speaker 2: less ice so smaller planets before the snow line in

336
00:15:26,080 --> 00:15:27,080
Speaker 2: the inner Solar system.

337
00:15:27,200 --> 00:15:28,840
Speaker 1: Right in the inner Solar system, you get all the

338
00:15:28,960 --> 00:15:30,040
Speaker 1: rocky planets.

339
00:15:29,720 --> 00:15:32,640
Speaker 2: Right exactly because the gas there is blown away by

340
00:15:32,640 --> 00:15:35,000
Speaker 2: the radiation from the ignition of the Sun. In the

341
00:15:35,080 --> 00:15:37,200
Speaker 2: very beginning of the Solar system, the Sun is pumping

342
00:15:37,200 --> 00:15:40,600
Speaker 2: out a huge amount of ultraviolet, very high energy photons,

343
00:15:40,920 --> 00:15:44,120
Speaker 2: which tends to blast the inner planets clean, which is why,

344
00:15:44,160 --> 00:15:47,440
Speaker 2: like our initial atmosphere on Earth was blown off by

345
00:15:47,480 --> 00:15:50,160
Speaker 2: this stellar wind in the very early years of the

346
00:15:50,160 --> 00:15:52,440
Speaker 2: Solar System. So you get the rocky planets in the core,

347
00:15:52,720 --> 00:15:55,040
Speaker 2: and then you get the gas and ice giants out

348
00:15:55,120 --> 00:15:56,680
Speaker 2: past the snow line.

349
00:15:56,520 --> 00:15:58,480
Speaker 1: Right, And I think the process is like, yep, these

350
00:15:58,600 --> 00:16:01,920
Speaker 1: rings kind of like Saturn has rings right now, and

351
00:16:01,960 --> 00:16:05,680
Speaker 1: the rings eventually little by little collapse into planets or

352
00:16:05,720 --> 00:16:07,320
Speaker 1: first planet tesimals first, right.

353
00:16:07,320 --> 00:16:09,920
Speaker 2: Yeah, planet testimals a super fun word. They sound like

354
00:16:10,080 --> 00:16:13,160
Speaker 2: many cute little planets where they're basically like building blocks

355
00:16:13,200 --> 00:16:15,760
Speaker 2: of planets, and they don't always form, right, which is

356
00:16:15,760 --> 00:16:18,320
Speaker 2: why you have like the asteroid belt and the Kuiper Belt.

357
00:16:18,640 --> 00:16:21,560
Speaker 2: It depends on the tidal forces of the nearby stuff,

358
00:16:21,840 --> 00:16:25,200
Speaker 2: so it's not happening in isolation. This is complicated interplay

359
00:16:25,240 --> 00:16:27,040
Speaker 2: between all of the objects.

360
00:16:26,680 --> 00:16:28,760
Speaker 1: Right, But it's kind of a bit of a runaway process.

361
00:16:28,800 --> 00:16:31,920
Speaker 1: Like once you seed a planet or once more you know,

362
00:16:31,960 --> 00:16:34,880
Speaker 1: some planet tesimals moush together, then that becomes kind of

363
00:16:34,920 --> 00:16:37,120
Speaker 1: a center of gravity and more and more stuff falls

364
00:16:37,120 --> 00:16:39,359
Speaker 1: into it, and that's kind of how you get a planet.

365
00:16:39,160 --> 00:16:41,440
Speaker 2: Right, Yeah, that's kind of how you get a planet exactly.

366
00:16:41,840 --> 00:16:45,360
Speaker 2: And in this initial picture, everything forms very orderly, like

367
00:16:45,440 --> 00:16:47,440
Speaker 2: they tend to be mostly in the same plane, and

368
00:16:47,480 --> 00:16:50,440
Speaker 2: it be mostly circular because you have this big disc

369
00:16:50,560 --> 00:16:52,520
Speaker 2: as we say, that collapses in the rings and then

370
00:16:52,560 --> 00:16:55,600
Speaker 2: planet ismals and then planets. But once you have these

371
00:16:55,760 --> 00:16:59,400
Speaker 2: large objects formed with their own significant gravity, then they

372
00:16:59,400 --> 00:17:01,400
Speaker 2: can start to hug on each other pretty hard, and

373
00:17:01,440 --> 00:17:04,360
Speaker 2: you can get instabilities, you can get chaos, you can

374
00:17:04,400 --> 00:17:07,960
Speaker 2: get resonances, and that's how planets can migrate, and they

375
00:17:07,960 --> 00:17:10,440
Speaker 2: can tug on each other and you might even lose.

376
00:17:10,240 --> 00:17:13,080
Speaker 1: One, right, because I guess there's no guarantee that your

377
00:17:13,160 --> 00:17:14,840
Speaker 1: orbit is going to be stable. I mean, it's such

378
00:17:14,840 --> 00:17:18,680
Speaker 1: a complex and you know, there's so many things moving

379
00:17:18,720 --> 00:17:21,080
Speaker 1: around that there's no guarantee that even if you're orbiting

380
00:17:21,119 --> 00:17:23,160
Speaker 1: around the Sun, you're going to be there forever, because

381
00:17:23,160 --> 00:17:26,040
Speaker 1: something else might come around and knock you off your

382
00:17:26,119 --> 00:17:28,280
Speaker 1: orbit or pull you away from your orbit, right.

383
00:17:28,119 --> 00:17:30,439
Speaker 2: And that can be things from outside the Solar System,

384
00:17:30,560 --> 00:17:34,359
Speaker 2: like a passing star can nudge something and perturb the

385
00:17:34,440 --> 00:17:37,840
Speaker 2: otherwise stable orbits of the Solar System like even just

386
00:17:37,880 --> 00:17:40,600
Speaker 2: a little nudge from a star that's coming nearby, it's

387
00:17:40,640 --> 00:17:42,320
Speaker 2: not like it has to pass right through the Solar

388
00:17:42,359 --> 00:17:45,720
Speaker 2: system can cause a cascade effect of instabilities. But also,

389
00:17:46,000 --> 00:17:48,159
Speaker 2: just like the planetismals and the Kuyper Belt or the

390
00:17:48,160 --> 00:17:50,879
Speaker 2: asteroid belt can tug on stuff, and enough of that

391
00:17:51,000 --> 00:17:52,840
Speaker 2: happening can cause things to go.

392
00:17:52,880 --> 00:17:56,240
Speaker 1: Wonky and wonky. They might have gone in our Solar system,

393
00:17:56,400 --> 00:17:58,919
Speaker 1: perhaps wonky enough to lose a couple of planets here

394
00:17:58,920 --> 00:18:02,240
Speaker 1: and there. Let's get into that idea and whether or

395
00:18:02,280 --> 00:18:05,639
Speaker 1: not we did misplace a couple of planets in our history.

396
00:18:05,720 --> 00:18:20,240
Speaker 1: But first let's take a quick break. All right, we're

397
00:18:20,240 --> 00:18:23,640
Speaker 1: talking about whether our Solar system has lost any planets.

398
00:18:23,720 --> 00:18:27,480
Speaker 1: I feel like that sounds very irresponsible of the Solar system.

399
00:18:27,800 --> 00:18:30,199
Speaker 1: Can would you say, like, have any planets escaped our

400
00:18:30,240 --> 00:18:30,840
Speaker 1: Solar system?

401
00:18:30,960 --> 00:18:33,920
Speaker 2: Maybe we've grown up and graduated planets. They're like off

402
00:18:34,000 --> 00:18:36,160
Speaker 2: into the universe living their best lives.

403
00:18:36,280 --> 00:18:38,239
Speaker 1: Yeah, there you go. You don't want it to live

404
00:18:38,240 --> 00:18:38,879
Speaker 1: at home forever.

405
00:18:39,560 --> 00:18:42,280
Speaker 2: Exactly when your kid graduates and goes to college, you

406
00:18:42,320 --> 00:18:43,680
Speaker 2: don't consider that you've lost them.

407
00:18:43,800 --> 00:18:47,480
Speaker 1: Yeah, there you go. So have we shepherded planets out

408
00:18:47,520 --> 00:18:50,400
Speaker 1: into the larger cosmos is the question of the day.

409
00:18:50,520 --> 00:18:52,480
Speaker 2: Yeah, in this scenario, they would like come back and

410
00:18:52,560 --> 00:18:54,399
Speaker 2: visit with their own little moons or something that we

411
00:18:54,440 --> 00:18:55,960
Speaker 2: could coop over. Oh look, how cute.

412
00:18:56,080 --> 00:18:58,560
Speaker 1: Oh yeah, yeah, except we already turned their bedroom into

413
00:18:58,600 --> 00:19:01,159
Speaker 1: like a workout room or a craft and so now

414
00:19:01,200 --> 00:19:02,920
Speaker 1: there's no room for them.

415
00:19:02,960 --> 00:19:04,800
Speaker 2: Sorry about that, your orbits being used?

416
00:19:05,640 --> 00:19:09,480
Speaker 1: Yes, sorry, you'll have to airbnb a nearby apartment or something.

417
00:19:09,840 --> 00:19:13,240
Speaker 1: But yeah, So it's possible in the early chaos of

418
00:19:13,280 --> 00:19:16,800
Speaker 1: a solar system to lose a planet, right because things

419
00:19:16,800 --> 00:19:20,679
Speaker 1: aren't quite settled. Even though we're all bound gravitationally to

420
00:19:20,880 --> 00:19:23,679
Speaker 1: the central star, things can get kind of wonky and

421
00:19:23,680 --> 00:19:27,680
Speaker 1: maybe wank enough to actually fling a planet out into space.

422
00:19:27,840 --> 00:19:30,760
Speaker 2: Exactly and when this happens is sort of the most

423
00:19:30,760 --> 00:19:34,440
Speaker 2: recent question people have been struggling with. There's a classic

424
00:19:34,560 --> 00:19:36,920
Speaker 2: model of the formation of the Solar system and how

425
00:19:36,920 --> 00:19:38,920
Speaker 2: the planets move around that we'll talk about. It's called

426
00:19:38,960 --> 00:19:43,240
Speaker 2: the Nice model because it was developed by researchers in Nice, France,

427
00:19:43,400 --> 00:19:45,840
Speaker 2: that has a bit of an issue with when exactly

428
00:19:45,880 --> 00:19:48,439
Speaker 2: all this chaos happened that might be solved by a

429
00:19:48,440 --> 00:19:51,399
Speaker 2: more recent model with a different picture for how these

430
00:19:51,400 --> 00:19:53,160
Speaker 2: instabilities might have been triggered.

431
00:19:53,240 --> 00:19:55,680
Speaker 1: Well, now, I wonder if some listeners out there might

432
00:19:55,680 --> 00:19:57,919
Speaker 1: be confused about how you can lose a planet, Like,

433
00:19:58,000 --> 00:20:00,800
Speaker 1: there isn't that much around us, right in terms of

434
00:20:00,880 --> 00:20:04,280
Speaker 1: other Solar systems or any large stars or galaxy or

435
00:20:04,359 --> 00:20:07,120
Speaker 1: you know, very heavy objects. So even if something gets

436
00:20:07,160 --> 00:20:09,440
Speaker 1: flung into space, wouldn't it eventually come back?

437
00:20:09,520 --> 00:20:12,680
Speaker 2: You're right that space near the Solar System is pretty empty.

438
00:20:12,920 --> 00:20:15,399
Speaker 2: I mean, the closest star is light years away, and

439
00:20:15,440 --> 00:20:17,800
Speaker 2: so its gravitational pull is pretty weak. But you can

440
00:20:17,840 --> 00:20:20,480
Speaker 2: still have an escape velocity. If you throw something hard

441
00:20:20,560 --> 00:20:23,119
Speaker 2: enough off the Earth, it will leave the Earth and

442
00:20:23,359 --> 00:20:26,040
Speaker 2: never return. If you throw something out of the Solar

443
00:20:26,080 --> 00:20:30,080
Speaker 2: System with enough velocity enough to escape the gravitational well

444
00:20:30,359 --> 00:20:33,159
Speaker 2: of the Solar System, then it will not return.

445
00:20:33,520 --> 00:20:35,680
Speaker 1: Mmmmm yeah, I think we talked about that in an

446
00:20:36,000 --> 00:20:38,240
Speaker 1: other episode. It's kind of a weird kind of math, right,

447
00:20:38,280 --> 00:20:40,400
Speaker 1: Like you need to have enough velocity so that as

448
00:20:40,440 --> 00:20:43,520
Speaker 1: you get further and further, the pool of gravity pulling

449
00:20:43,560 --> 00:20:45,679
Speaker 1: your back gets weaker and weaker, and so actually you

450
00:20:46,280 --> 00:20:49,080
Speaker 1: kind of outrun the pool of gravity exactly.

451
00:20:49,119 --> 00:20:51,720
Speaker 2: It seemed confusing because you know that gravity has an

452
00:20:51,760 --> 00:20:54,320
Speaker 2: infinite extent, like no matter how far away you are,

453
00:20:54,400 --> 00:20:56,960
Speaker 2: and the Sun is always pulling on you. But just

454
00:20:56,960 --> 00:20:59,480
Speaker 2: because there are infinite number of contributions doesn't mean it

455
00:20:59,560 --> 00:21:01,720
Speaker 2: adds up to an infinite force. It's just like any

456
00:21:01,760 --> 00:21:04,760
Speaker 2: integral or converging series. It can add to a finite

457
00:21:04,800 --> 00:21:06,760
Speaker 2: amount of energy. So as long as you have more

458
00:21:06,880 --> 00:21:09,760
Speaker 2: energy than the sum of all the tugs the Sun

459
00:21:09,800 --> 00:21:12,840
Speaker 2: will ever pull on you, you can escape the Solar System.

460
00:21:12,920 --> 00:21:15,080
Speaker 2: So if, for example, you have a planet that gets

461
00:21:15,080 --> 00:21:18,200
Speaker 2: a push from another planet and gets flung out into

462
00:21:18,240 --> 00:21:20,399
Speaker 2: the deep dark space, it might never return.

463
00:21:20,640 --> 00:21:22,800
Speaker 1: Yeah, I guess sort of like we've done with spacecraft

464
00:21:22,800 --> 00:21:25,080
Speaker 1: that we sent out into space right like it left

465
00:21:25,119 --> 00:21:27,240
Speaker 1: Earth eventually, it was going so fast it left the

466
00:21:27,280 --> 00:21:30,440
Speaker 1: gravity of Earth and through the gravity of maybe other planets.

467
00:21:30,480 --> 00:21:32,359
Speaker 1: And now we have some that are going out of

468
00:21:32,400 --> 00:21:33,680
Speaker 1: the Solar System exactly.

469
00:21:33,720 --> 00:21:35,520
Speaker 2: That can be a little bit more complicated because they

470
00:21:35,560 --> 00:21:38,680
Speaker 2: can have rockets and they can use gravitational assists from

471
00:21:38,720 --> 00:21:41,640
Speaker 2: other planets, but the principle is the same. Like Voyager

472
00:21:41,800 --> 00:21:44,919
Speaker 2: and Pioneer, they have enough velocity that they're leaving the

473
00:21:44,960 --> 00:21:48,120
Speaker 2: Solar System without any more rocket burns or gravitational assists.

474
00:21:48,320 --> 00:21:49,920
Speaker 2: It's definitely possible to leave home.

475
00:21:50,040 --> 00:21:53,520
Speaker 1: All right. Well, now the question here today is have

476
00:21:53,560 --> 00:21:56,399
Speaker 1: we actually lost any planets? Did the Solar System have

477
00:21:56,520 --> 00:21:58,520
Speaker 1: more planets than the eight that we have now, and

478
00:21:58,840 --> 00:22:01,520
Speaker 1: have we missed or have any left home?

479
00:22:01,600 --> 00:22:03,240
Speaker 2: But if you look at the pattern of the planets

480
00:22:03,240 --> 00:22:04,840
Speaker 2: that we have now and you try to tell a

481
00:22:04,880 --> 00:22:07,480
Speaker 2: story about how we got there, it's a hard thing

482
00:22:07,520 --> 00:22:10,560
Speaker 2: to do without another planet. The patterns that we see

483
00:22:10,600 --> 00:22:13,480
Speaker 2: in the eccentricities of the planets and the structure of

484
00:22:13,520 --> 00:22:16,879
Speaker 2: the Kuiper Belt and the asteroids is much easier to

485
00:22:16,960 --> 00:22:20,479
Speaker 2: explain if there was at one point another ice giant

486
00:22:20,800 --> 00:22:24,240
Speaker 2: like Neptune that was flung out of the Solar System.

487
00:22:24,320 --> 00:22:25,959
Speaker 1: I mean, you sort of look at how the planets

488
00:22:25,960 --> 00:22:29,200
Speaker 1: are moving now and their orbits, and you basically hit

489
00:22:29,200 --> 00:22:31,600
Speaker 1: the rewind button, kind of like you use math and

490
00:22:31,680 --> 00:22:36,240
Speaker 1: a computer to backtrack what the Solar System was doing

491
00:22:36,320 --> 00:22:38,720
Speaker 1: millions and millions of years ago, and you're saying that

492
00:22:38,760 --> 00:22:39,920
Speaker 1: it doesn't make sense or what.

493
00:22:40,000 --> 00:22:42,399
Speaker 2: It actually usually works. In the forward direction, like you

494
00:22:42,520 --> 00:22:46,159
Speaker 2: start from the Protosolar System and try to evolve forward

495
00:22:46,280 --> 00:22:48,960
Speaker 2: and see if it matches what we see today. Conceptually

496
00:22:48,960 --> 00:22:51,520
Speaker 2: it's the same as backtracking, but the way the simulations

497
00:22:51,560 --> 00:22:54,920
Speaker 2: actually work is forwards. You know, we model physics equations

498
00:22:54,920 --> 00:22:57,159
Speaker 2: forwards in time, and we try to see if we

499
00:22:57,240 --> 00:22:59,800
Speaker 2: can get to the current Solar system and explain everything

500
00:22:59,840 --> 00:23:02,120
Speaker 2: we see. And what we find is that doesn't really

501
00:23:02,160 --> 00:23:03,359
Speaker 2: work without another planet.

502
00:23:03,440 --> 00:23:05,280
Speaker 1: But are there like a million things that could have

503
00:23:05,280 --> 00:23:08,639
Speaker 1: happened in between? Absolutely, how do you make it match

504
00:23:09,040 --> 00:23:11,800
Speaker 1: what we have now? Like, what do you start with?

505
00:23:12,640 --> 00:23:14,439
Speaker 1: And if you can make it match, how do you

506
00:23:14,440 --> 00:23:15,960
Speaker 1: know it's not just you're making it error?

507
00:23:16,119 --> 00:23:20,600
Speaker 2: Absolutely, it's not definitive, right, it's statistical. It's totally possible

508
00:23:20,760 --> 00:23:23,920
Speaker 2: that our solar system could have arisen without another planet.

509
00:23:24,240 --> 00:23:26,600
Speaker 2: But it's just a question of what's more likely. Like

510
00:23:26,640 --> 00:23:29,400
Speaker 2: when you run the simulations of our solar system, how

511
00:23:29,400 --> 00:23:31,600
Speaker 2: many times do you get to something like what we

512
00:23:31,680 --> 00:23:35,120
Speaker 2: have now with a lost planet and without a lost planet?

513
00:23:35,600 --> 00:23:38,480
Speaker 2: And so is it just easier to make this arrangement

514
00:23:38,560 --> 00:23:41,359
Speaker 2: with a lost planet or without? It's totally possible to

515
00:23:41,359 --> 00:23:43,520
Speaker 2: do it without, but it's just less likely. It happens

516
00:23:43,560 --> 00:23:45,120
Speaker 2: in fewer of those simulations.

517
00:23:45,880 --> 00:23:47,600
Speaker 1: And by like what we have now, you don't mean

518
00:23:47,680 --> 00:23:49,720
Speaker 1: like exactly what we have now just kind of like

519
00:23:49,800 --> 00:23:51,000
Speaker 1: sort of like what we have now.

520
00:23:51,119 --> 00:23:53,600
Speaker 2: If you run enough simulations, you can get essentially a

521
00:23:53,680 --> 00:23:56,360
Speaker 2: sense for what's more likely and what's less likely under

522
00:23:56,400 --> 00:23:59,960
Speaker 2: various hypotheses. And if you have another planet in your system,

523
00:24:00,240 --> 00:24:03,320
Speaker 2: then you get more simulations that are similar to ours. Yeah,

524
00:24:03,560 --> 00:24:06,399
Speaker 2: so more like probability gets clustered in the kind of

525
00:24:06,520 --> 00:24:08,560
Speaker 2: arrangement that we have now. And the cool thing about

526
00:24:08,560 --> 00:24:10,320
Speaker 2: that is that it tells the story. You can look

527
00:24:10,359 --> 00:24:12,639
Speaker 2: at those simulations and you can see, oh, what happened

528
00:24:12,640 --> 00:24:14,600
Speaker 2: in the inner what happened in the early days of

529
00:24:14,640 --> 00:24:16,679
Speaker 2: the Solar System? How did this happen?

530
00:24:17,320 --> 00:24:19,919
Speaker 1: Okay, So then scientists have been running these simulations and

531
00:24:19,960 --> 00:24:22,280
Speaker 1: it's kind of hard to get what we have now

532
00:24:22,560 --> 00:24:26,840
Speaker 1: without some mystery planet that moved away from the Solar System.

533
00:24:26,960 --> 00:24:28,240
Speaker 1: How did scientists think that happen?

534
00:24:28,320 --> 00:24:31,840
Speaker 2: So the original models, called the NIE model, basically blames

535
00:24:31,840 --> 00:24:34,919
Speaker 2: it on the Kuiper Belt. So in the original Solar system,

536
00:24:34,960 --> 00:24:39,080
Speaker 2: you have Jupiter, Saturn, Urinus, Neptune, all formed in very nice,

537
00:24:39,200 --> 00:24:41,920
Speaker 2: neat circular orbits like we talked about, in fairly closely

538
00:24:41,960 --> 00:24:44,560
Speaker 2: spaced to each other. But then you have these planetismals

539
00:24:44,600 --> 00:24:47,000
Speaker 2: out in the Kuiper Belt that haven't formed into planets,

540
00:24:47,160 --> 00:24:50,160
Speaker 2: but they're tugging on Neptune, they're tugging on Urinus, they're

541
00:24:50,200 --> 00:24:52,520
Speaker 2: tugging on Saturn, and they get pulled into the inner

542
00:24:52,560 --> 00:24:55,080
Speaker 2: Solar System. And when that happens, these big planets get

543
00:24:55,119 --> 00:24:57,320
Speaker 2: pushed out a little bit, and then the planetismal falls

544
00:24:57,359 --> 00:25:00,159
Speaker 2: further into the Solar System until it reaches Jupiter, and

545
00:25:00,160 --> 00:25:03,240
Speaker 2: then Jupiter actually pushes it back out and Jupiter gets

546
00:25:03,240 --> 00:25:06,160
Speaker 2: pushed in. The effect of these little planetismals, these little

547
00:25:06,160 --> 00:25:09,840
Speaker 2: tugs is to pull out Neptune, Saturn, Uriness and to

548
00:25:09,880 --> 00:25:12,800
Speaker 2: push Jupiter in a little bit. So they're disturbing the

549
00:25:12,840 --> 00:25:14,640
Speaker 2: Solar System. And you might think, well, what can one

550
00:25:14,680 --> 00:25:17,240
Speaker 2: little rock do? And the key is that there's lots

551
00:25:17,280 --> 00:25:20,120
Speaker 2: of these rocks, and so over time this can really

552
00:25:20,160 --> 00:25:21,640
Speaker 2: have an effect on the orbit of the.

553
00:25:21,600 --> 00:25:25,280
Speaker 1: Planets because we know that at around that space, that

554
00:25:25,480 --> 00:25:27,440
Speaker 1: ring of the Solar System, you had a lot of

555
00:25:27,440 --> 00:25:28,840
Speaker 1: big rocks, and maybe you have a lot of big

556
00:25:28,920 --> 00:25:30,040
Speaker 1: rocks right now exactly.

557
00:25:30,080 --> 00:25:32,920
Speaker 2: The Kuiper Belt is huge. There could be like trillions

558
00:25:32,960 --> 00:25:35,720
Speaker 2: of objects out there. We think today it's the source

559
00:25:35,760 --> 00:25:38,480
Speaker 2: of comets that fall into the Solar System, the short

560
00:25:38,520 --> 00:25:41,400
Speaker 2: period comets. There's an even bigger blob of stuff out

561
00:25:41,440 --> 00:25:43,199
Speaker 2: in the Oort Cloud. It might be the source of

562
00:25:43,280 --> 00:25:46,520
Speaker 2: long term comments, but it's an enormous, massive stuff out there,

563
00:25:46,680 --> 00:25:48,720
Speaker 2: and each of those little bits as they interact with

564
00:25:48,760 --> 00:25:51,119
Speaker 2: the Solar System can give a little tug. You have

565
00:25:51,240 --> 00:25:54,359
Speaker 2: these nice circular orbits that were formed initially, but now

566
00:25:54,400 --> 00:25:57,040
Speaker 2: they're getting perturbed by these tugs from all these rocks

567
00:25:57,080 --> 00:25:58,600
Speaker 2: in the Kuiper Belt. Mmm.

568
00:25:59,000 --> 00:26:01,760
Speaker 1: Okay, scientist think that maybe these rocks from the Kuyper

569
00:26:01,800 --> 00:26:05,040
Speaker 1: berl maybe cause some planet that we had before to

570
00:26:05,200 --> 00:26:06,359
Speaker 1: exit the Solar System.

571
00:26:06,400 --> 00:26:09,800
Speaker 2: Well, essentially leads to some instability because you're pushing Jupiter in,

572
00:26:10,040 --> 00:26:13,879
Speaker 2: you're pushing Neptune, Saturn, Urinus out, and then those planets

573
00:26:13,920 --> 00:26:15,920
Speaker 2: start to interact like they used to be in a nice,

574
00:26:15,920 --> 00:26:19,360
Speaker 2: happy orbit. But now you get instabilities and resonances from

575
00:26:19,400 --> 00:26:23,000
Speaker 2: those planets themselves. Jupiter starts to drift inwards, and then

576
00:26:23,080 --> 00:26:26,040
Speaker 2: Saturn pulls on Jupiter, and Jupiter pulls on Saturn. You

577
00:26:26,080 --> 00:26:28,440
Speaker 2: start to get a regular orbits, and Saturn actually pulling

578
00:26:28,440 --> 00:26:31,199
Speaker 2: on Jupiter is what saves it. Saturn pulls on Jupiter

579
00:26:31,240 --> 00:26:34,480
Speaker 2: and changes its direction so it migrates back out away

580
00:26:34,520 --> 00:26:37,040
Speaker 2: from the Sun. Without Saturn there, it might have been

581
00:26:37,080 --> 00:26:39,440
Speaker 2: that Jupiter would have just like plummeted into the Sun

582
00:26:39,600 --> 00:26:41,200
Speaker 2: thanks to the influence of the Kuiper Belt.

583
00:26:41,280 --> 00:26:43,520
Speaker 1: You know, it all sounds kind of complicated, So I

584
00:26:43,520 --> 00:26:46,360
Speaker 1: wonder why do scientist think that making it more complicated

585
00:26:46,359 --> 00:26:49,720
Speaker 1: by adding another planet makes it easier to understand? Like

586
00:26:49,760 --> 00:26:52,600
Speaker 1: it's all really complex dynamics, right, Like, so then how

587
00:26:52,640 --> 00:26:56,520
Speaker 1: does adding another planet make it easier to predict, like

588
00:26:56,560 --> 00:27:00,320
Speaker 1: what's the missing thing that we currently have? That missing

589
00:27:00,359 --> 00:27:01,439
Speaker 1: planet would help with.

590
00:27:01,640 --> 00:27:03,760
Speaker 2: Some of the features of our Solar system that we

591
00:27:03,840 --> 00:27:07,240
Speaker 2: see today are difficult to explain without adding another planet,

592
00:27:07,800 --> 00:27:10,680
Speaker 2: you know, like the irregular orbits of Jupiter and Saturn.

593
00:27:10,720 --> 00:27:13,119
Speaker 2: They're not perfect circles. There are sort of ellipses that

594
00:27:13,200 --> 00:27:16,400
Speaker 2: have like a five percent eccentricity, And there's this structure

595
00:27:16,520 --> 00:27:18,840
Speaker 2: in the material of the Kuiper Belt. A lot of

596
00:27:18,840 --> 00:27:20,520
Speaker 2: it seems to have been lost, and a lot of

597
00:27:20,560 --> 00:27:23,159
Speaker 2: the rest of it is in resonance with Neptune. And

598
00:27:23,200 --> 00:27:25,960
Speaker 2: these things aren't like smoking guns that say like, oh, look,

599
00:27:26,040 --> 00:27:28,199
Speaker 2: there has to be another planet here. But when you

600
00:27:28,280 --> 00:27:30,720
Speaker 2: run the simulations, you get these kind of features more

601
00:27:30,760 --> 00:27:33,800
Speaker 2: often when you add another planet. If you put another

602
00:27:33,840 --> 00:27:37,400
Speaker 2: ice giant in around the size of Neptune between Saturn

603
00:27:37,440 --> 00:27:40,160
Speaker 2: and Urinus, then the story you get when you run

604
00:27:40,200 --> 00:27:44,000
Speaker 2: these simulations more closely resembles the Solar System we have today.

605
00:27:44,119 --> 00:27:47,040
Speaker 1: And I guess scientists just throw this mystery planet in

606
00:27:47,160 --> 00:27:49,960
Speaker 1: and all kinds of velocities in all kinds of sizes,

607
00:27:50,000 --> 00:27:52,400
Speaker 1: and you sort of see overall, like, hey, it does

608
00:27:52,480 --> 00:27:55,720
Speaker 1: kind of shape the Solar System more into what we

609
00:27:55,760 --> 00:27:56,160
Speaker 1: have now.

610
00:27:56,280 --> 00:27:58,119
Speaker 2: Yeah. Another way to say it is like they were

611
00:27:58,200 --> 00:28:01,000
Speaker 2: running the simulations with just the planets and they were

612
00:28:01,040 --> 00:28:05,080
Speaker 2: noticing that they pretty rarely ended up describing the situation

613
00:28:05,160 --> 00:28:07,359
Speaker 2: that we see today, Like it was very unlikely to

614
00:28:07,400 --> 00:28:10,240
Speaker 2: get Jupiter and Saturn to have these eccentricities, and to

615
00:28:10,280 --> 00:28:14,080
Speaker 2: have these asteroid belts along Jupiter's orbit, the Trojans and

616
00:28:14,119 --> 00:28:16,760
Speaker 2: the Greek camp of asteroid belts, those things were pretty

617
00:28:16,880 --> 00:28:19,760
Speaker 2: rare to get in a Solar system without this additional planet.

618
00:28:19,760 --> 00:28:21,760
Speaker 2: But when you put that new planet in, it started

619
00:28:21,760 --> 00:28:23,399
Speaker 2: to be less unlikely. It started to be like, oh,

620
00:28:23,440 --> 00:28:25,880
Speaker 2: this kind of thing happens pretty frequently, and so it's

621
00:28:25,920 --> 00:28:27,560
Speaker 2: just a question of like, how do you explain it.

622
00:28:27,560 --> 00:28:30,040
Speaker 2: It's not the only possible story, right, Maybe there are

623
00:28:30,040 --> 00:28:33,399
Speaker 2: two other planets. Maybe something else happened that could explain this,

624
00:28:33,720 --> 00:28:35,640
Speaker 2: but it does make the story more likely.

625
00:28:36,480 --> 00:28:39,360
Speaker 1: Maybe the planet had a big fight with Jupiter, stormed

626
00:28:39,360 --> 00:28:41,440
Speaker 1: out of the house with all their bags, left to

627
00:28:41,480 --> 00:28:43,520
Speaker 1: go live with their aunt or their niece. This is

628
00:28:43,680 --> 00:28:45,640
Speaker 1: the Nice model, right, This.

629
00:28:45,400 --> 00:28:48,520
Speaker 2: Is the Nie model exactly. They went to live with

630
00:28:48,560 --> 00:28:49,400
Speaker 2: their aunt in France.

631
00:28:49,680 --> 00:28:51,840
Speaker 1: So then that's one model you're seeing. One model says

632
00:28:51,840 --> 00:28:53,880
Speaker 1: and maybe it was all these big rocks from the

633
00:28:53,960 --> 00:28:56,440
Speaker 1: Kuiper Belt that maybe caused a lot of instability out

634
00:28:56,440 --> 00:28:58,920
Speaker 1: there in the icy planets, and then maybe it caused

635
00:28:58,920 --> 00:29:01,280
Speaker 1: a planet that we used to have to flyway exactly.

636
00:29:01,280 --> 00:29:03,400
Speaker 2: And one of the nice things about this model until

637
00:29:03,440 --> 00:29:06,160
Speaker 2: recently was that it lined up with other pieces of

638
00:29:06,200 --> 00:29:09,960
Speaker 2: evidence for when this instability happened. And in the Nice model,

639
00:29:10,000 --> 00:29:12,920
Speaker 2: this happens like about a billion years after the Solar

640
00:29:12,920 --> 00:29:15,840
Speaker 2: system is formed, so you get like the ignition of

641
00:29:15,880 --> 00:29:17,920
Speaker 2: the Sun, you get the formation and the gas planets

642
00:29:17,920 --> 00:29:20,840
Speaker 2: and the rocky planets. Things cycle around for a little while,

643
00:29:21,080 --> 00:29:23,120
Speaker 2: and it takes time for the Kuyper Belt to sort

644
00:29:23,120 --> 00:29:26,000
Speaker 2: of drive this because these are tiny little rocks. This

645
00:29:26,040 --> 00:29:28,240
Speaker 2: sort of lines up with another piece of evidence from

646
00:29:28,280 --> 00:29:30,400
Speaker 2: looking at our Moon. Our moon is a great record

647
00:29:30,480 --> 00:29:33,200
Speaker 2: for impacts in the Solar System, like when rocks have

648
00:29:33,320 --> 00:29:35,920
Speaker 2: been raining down in the inner Solar System. And when

649
00:29:35,920 --> 00:29:38,240
Speaker 2: the astronauts in the Apollo mission went to the Moon,

650
00:29:38,400 --> 00:29:40,600
Speaker 2: they gathered a bunch of samples to study, like the

651
00:29:40,600 --> 00:29:42,800
Speaker 2: craters and the impacts, to try to get a sense

652
00:29:42,840 --> 00:29:44,920
Speaker 2: for like what is the history of the Solar system.

653
00:29:45,080 --> 00:29:48,120
Speaker 2: One of them been sort of more or less impacts

654
00:29:48,280 --> 00:29:50,560
Speaker 2: when it's been like bad weather and good weather, and

655
00:29:50,640 --> 00:29:52,479
Speaker 2: for a long time, there was this evidence for what

656
00:29:52,520 --> 00:29:55,640
Speaker 2: we call a late heavy bombardment, that there's this period

657
00:29:55,680 --> 00:29:58,280
Speaker 2: of billion years after the Solar system formed when a

658
00:29:58,320 --> 00:30:00,760
Speaker 2: lot of rocks were raining down in the the Solar system,

659
00:30:01,080 --> 00:30:02,640
Speaker 2: And that kind of lines up with the story of

660
00:30:02,680 --> 00:30:04,840
Speaker 2: the nice model that like all these rocks from the

661
00:30:04,920 --> 00:30:07,160
Speaker 2: Kuiper Belt were coming in and making trouble and maybe

662
00:30:07,200 --> 00:30:09,880
Speaker 2: also some of them were landing on the Moon. So

663
00:30:09,920 --> 00:30:11,480
Speaker 2: that was sort of a nice story.

664
00:30:11,160 --> 00:30:14,840
Speaker 1: For a while, meaning like there's a lot of activity

665
00:30:14,840 --> 00:30:17,840
Speaker 1: from the Kuiper Bell which may have contributed to us

666
00:30:17,920 --> 00:30:19,960
Speaker 1: kicking out an icy planet.

667
00:30:19,680 --> 00:30:21,920
Speaker 2: Exactly, and until a few years ago that all seemed

668
00:30:21,920 --> 00:30:23,600
Speaker 2: to kind of hang together. But then there was a

669
00:30:23,680 --> 00:30:27,040
Speaker 2: reanalysis of this data from the Moon and it turns

670
00:30:27,040 --> 00:30:28,280
Speaker 2: out that it may have been a mistake.

671
00:30:28,520 --> 00:30:31,400
Speaker 1: Well, we lost the theory the dog at theory.

672
00:30:31,480 --> 00:30:33,840
Speaker 2: It turns out of the way the astronauts gathered the

673
00:30:33,920 --> 00:30:37,640
Speaker 2: data that may have basically only collected data from one

674
00:30:37,720 --> 00:30:40,520
Speaker 2: big impact. So what we thought was a bunch of

675
00:30:40,560 --> 00:30:43,240
Speaker 2: impacts that all happened at the same time, like three

676
00:30:43,280 --> 00:30:45,840
Speaker 2: and a half billion years ago, might have actually just

677
00:30:45,880 --> 00:30:48,920
Speaker 2: been one big impact that the astronauts gathered from. So

678
00:30:48,920 --> 00:30:51,480
Speaker 2: it could have been like essentially just a statistical anomaly

679
00:30:51,520 --> 00:30:52,840
Speaker 2: in the data that made it look like there was

680
00:30:52,920 --> 00:30:55,600
Speaker 2: really bad weather for like a few hundred million years

681
00:30:55,680 --> 00:30:57,360
Speaker 2: three and a half billion years ago, But it was

682
00:30:57,400 --> 00:30:59,880
Speaker 2: really just one bad day that the astronauts happened to

683
00:31:00,000 --> 00:31:00,800
Speaker 2: elect data from.

684
00:31:00,960 --> 00:31:03,959
Speaker 1: Wait what, so we didn't we just had one sample.

685
00:31:04,120 --> 00:31:06,240
Speaker 1: We didn't take some samples from all over the Moon

686
00:31:06,400 --> 00:31:10,040
Speaker 1: or analyze the craters visually through telescopes, so.

687
00:31:10,000 --> 00:31:11,720
Speaker 2: We don't have samples from all over the Moon. And

688
00:31:11,720 --> 00:31:14,680
Speaker 2: they definitely collected a bunch of samples from different locations,

689
00:31:15,000 --> 00:31:17,280
Speaker 2: and that's why they thought maybe this was like a

690
00:31:17,320 --> 00:31:20,800
Speaker 2: fair sample from everywhere on the Moon. But a reanalysis

691
00:31:20,840 --> 00:31:24,360
Speaker 2: of it suggests that a single impact site Imbrium might

692
00:31:24,360 --> 00:31:27,200
Speaker 2: be responsible for basically all of the evidence that the

693
00:31:27,400 --> 00:31:29,520
Speaker 2: astronauts gathered. I don't know if the astronauts are being

694
00:31:29,560 --> 00:31:31,960
Speaker 2: lazy and not following instructions or if it was not

695
00:31:32,040 --> 00:31:35,480
Speaker 2: a well organized study, but more recent analysis suggests there

696
00:31:35,480 --> 00:31:38,400
Speaker 2: may have been no late heavy bombardment. There may just

697
00:31:38,440 --> 00:31:40,920
Speaker 2: be like a gradual decline in the number of impacts

698
00:31:40,920 --> 00:31:41,480
Speaker 2: over time.

699
00:31:42,040 --> 00:31:44,800
Speaker 1: And so maybe this idea that kyper Berl maybe caused

700
00:31:44,880 --> 00:31:47,600
Speaker 1: us to lose an icy planet maybe didn't really happen,

701
00:31:47,920 --> 00:31:50,640
Speaker 1: or could it still have happened without this late heavy bombardment.

702
00:31:50,840 --> 00:31:53,240
Speaker 2: This really causes us to doubt that model. And there's

703
00:31:53,360 --> 00:31:56,680
Speaker 2: been another lingering problem with this Nie model that has

704
00:31:56,720 --> 00:32:00,000
Speaker 2: never really been answered, which is why the terrestrial planets

705
00:32:00,080 --> 00:32:02,800
Speaker 2: kind of survived it. If you have these gas giants

706
00:32:02,880 --> 00:32:05,760
Speaker 2: doing this dance a billion years after the Solar System

707
00:32:05,800 --> 00:32:08,640
Speaker 2: is formed, when Earth and Mars are also already formed,

708
00:32:09,080 --> 00:32:11,760
Speaker 2: then how did the Earth and Mars and Venus survive

709
00:32:12,000 --> 00:32:15,440
Speaker 2: all these gravitational tugs. If Jupiter comes into the inner

710
00:32:15,480 --> 00:32:18,640
Speaker 2: Solar System basically turns around at the asteroid belt, how

711
00:32:18,680 --> 00:32:21,640
Speaker 2: does Mars stay in orbit? How does Earth stay where

712
00:32:21,680 --> 00:32:24,160
Speaker 2: it is? So one concerned about the Nie model has

713
00:32:24,160 --> 00:32:27,640
Speaker 2: always been how did the terrestrial planets not get disrupted

714
00:32:27,680 --> 00:32:30,760
Speaker 2: by the giants. So now there's a news story about

715
00:32:30,800 --> 00:32:33,560
Speaker 2: when this instability happened and what the cause was that

716
00:32:33,640 --> 00:32:36,640
Speaker 2: doesn't rely on this late heavy bombardment and places the

717
00:32:36,640 --> 00:32:38,480
Speaker 2: blame on the instability somewhere else.

718
00:32:39,200 --> 00:32:41,120
Speaker 1: But I guess why do we assume that there was

719
00:32:41,360 --> 00:32:44,480
Speaker 1: an instability because we think that maybe we did lose

720
00:32:44,480 --> 00:32:45,280
Speaker 1: a planet.

721
00:32:44,960 --> 00:32:47,480
Speaker 2: Because we can't explain the orbits and the eccentricities and

722
00:32:47,520 --> 00:32:50,160
Speaker 2: the structure of the Kyper Belt without some kind of

723
00:32:50,240 --> 00:32:52,680
Speaker 2: motion of these planets. We know the planets moved around,

724
00:32:52,960 --> 00:32:55,440
Speaker 2: we know there was interaction. We know that they did

725
00:32:55,480 --> 00:32:57,560
Speaker 2: not form in the order that we see them today.

726
00:32:57,760 --> 00:33:01,440
Speaker 1: All right, So then what's this new model? Not so nice,

727
00:33:02,080 --> 00:33:06,240
Speaker 1: the less nice model exactly, not the Nie model, the

728
00:33:06,280 --> 00:33:07,160
Speaker 1: Nephew model.

729
00:33:07,720 --> 00:33:11,440
Speaker 2: The nibbling model. So this model is called the rebound model,

730
00:33:11,600 --> 00:33:15,200
Speaker 2: and it suggests that this instability happened much much earlier. Actually,

731
00:33:15,240 --> 00:33:18,080
Speaker 2: while the rocky planets were forming, or maybe even before

732
00:33:18,200 --> 00:33:21,600
Speaker 2: they formed, that was basically an early instability.

733
00:33:21,800 --> 00:33:24,640
Speaker 1: Well, that's a big difference in timescale, But don't your

734
00:33:24,640 --> 00:33:27,880
Speaker 1: simulations as a solar system sort of help you pinpoint

735
00:33:27,920 --> 00:33:28,560
Speaker 1: when it happened.

736
00:33:28,600 --> 00:33:30,320
Speaker 2: It turns out that the simulations can come in to

737
00:33:30,360 --> 00:33:34,040
Speaker 2: either an early instability or a later instability, like the

738
00:33:34,080 --> 00:33:36,880
Speaker 2: instability for in the nice model, like a billion years

739
00:33:36,920 --> 00:33:39,680
Speaker 2: after the formation of the Solar system, can explain the

740
00:33:39,800 --> 00:33:42,560
Speaker 2: orbits that we got if there, in fact was a

741
00:33:42,600 --> 00:33:45,320
Speaker 2: bunch of interactions from the Kuiper Belt. But you could

742
00:33:45,400 --> 00:33:48,360
Speaker 2: also have an instability much earlier on that could reproduce

743
00:33:48,400 --> 00:33:50,680
Speaker 2: the orbits and the eccentricities that we see today.

744
00:33:51,600 --> 00:33:53,720
Speaker 1: All right, so then what does this model say? What

745
00:33:53,840 --> 00:33:56,400
Speaker 1: happened according to this model? So this is called the

746
00:33:56,440 --> 00:33:59,680
Speaker 1: rebound model, and essentially the instability trigger here, the thing

747
00:33:59,720 --> 00:34:03,440
Speaker 1: that can kicked off all this bouncing around was the

748
00:34:03,440 --> 00:34:06,960
Speaker 1: interaction of the planets with this gas. Imagine the formation

749
00:34:07,000 --> 00:34:09,040
Speaker 1: of the Solar system, as we talked about earlier. You

750
00:34:09,120 --> 00:34:11,760
Speaker 1: have these planets forming and they're pulling their stuff together,

751
00:34:11,920 --> 00:34:14,759
Speaker 1: but you still have something of a protoplanetary disk. You

752
00:34:14,760 --> 00:34:16,880
Speaker 1: still have a bunch of gas sort of in between

753
00:34:16,920 --> 00:34:18,840
Speaker 1: the planets. Now we don't have that today, and the

754
00:34:18,880 --> 00:34:21,479
Speaker 1: reason is that the Sun has effectively blown all that out.

755
00:34:21,520 --> 00:34:24,240
Speaker 1: As the Sun triggered and the ignited and its radiation

756
00:34:24,400 --> 00:34:26,600
Speaker 1: grew and grew, it blew out all that gas from

757
00:34:26,640 --> 00:34:29,560
Speaker 1: the Solar system. So in the first ten million years

758
00:34:29,680 --> 00:34:32,919
Speaker 1: or so, that gas disc is sort of moving out

759
00:34:33,000 --> 00:34:35,520
Speaker 1: through the Solar System and it affects the orbits of

760
00:34:35,560 --> 00:34:38,040
Speaker 1: those planets. If the planets are passing through the gas,

761
00:34:38,080 --> 00:34:40,800
Speaker 1: it slows them down, and if that gas is getting

762
00:34:40,840 --> 00:34:44,120
Speaker 1: pushed out by the star, it actually carries those planets

763
00:34:44,120 --> 00:34:46,839
Speaker 1: with them a little bit. So as this gas disc

764
00:34:46,920 --> 00:34:49,160
Speaker 1: is getting pushed out of the Solar System, it passes

765
00:34:49,280 --> 00:34:51,839
Speaker 1: through all of these orbits and it gives them all

766
00:34:51,880 --> 00:34:55,000
Speaker 1: a little tweak. So this rebound model suggests that the

767
00:34:55,040 --> 00:34:57,920
Speaker 1: interaction of the planets with this gas disc as it's

768
00:34:57,920 --> 00:35:00,680
Speaker 1: getting blown out of the Solar System and trigger these

769
00:35:00,719 --> 00:35:03,600
Speaker 1: same instabilities and can explain all the features we see

770
00:35:03,640 --> 00:35:06,279
Speaker 1: in the Solar system today. But couldn't you kind of

771
00:35:06,320 --> 00:35:08,920
Speaker 1: make the same argument as before with the other model,

772
00:35:09,000 --> 00:35:11,279
Speaker 1: like Wooden Huck How is it then that we'd the

773
00:35:11,280 --> 00:35:13,759
Speaker 1: Earth and Mars and Venus have such a nice even

774
00:35:13,840 --> 00:35:16,399
Speaker 1: orbits if we were disturbed and blown out.

775
00:35:16,520 --> 00:35:19,759
Speaker 2: Yeah, great question. It's because this happened much earlier, and

776
00:35:19,800 --> 00:35:23,040
Speaker 2: so essentially this happened before those terrestrial planets even form.

777
00:35:23,120 --> 00:35:25,960
Speaker 2: The terrestrial planets we think formed after the gas giants.

778
00:35:26,239 --> 00:35:28,120
Speaker 2: M how come the gas giants have a lot of

779
00:35:28,160 --> 00:35:30,760
Speaker 2: advantages over the rocky planets in the inner solar systems.

780
00:35:31,040 --> 00:35:33,120
Speaker 2: Number one, there's ice out there, which is like a

781
00:35:33,200 --> 00:35:35,920
Speaker 2: solid that can help seed the formation of planets. To

782
00:35:36,040 --> 00:35:38,200
Speaker 2: there's a lot more gas out there because the Sun

783
00:35:38,239 --> 00:35:40,800
Speaker 2: hasn't gobbled it up, and you don't have this proto

784
00:35:41,000 --> 00:35:44,120
Speaker 2: star messing everything up and heating things. So it's much colder,

785
00:35:44,160 --> 00:35:46,680
Speaker 2: which makes it easier for gravity to pull things together.

786
00:35:46,840 --> 00:35:49,160
Speaker 2: So the outer Solar system is a much easier place

787
00:35:49,200 --> 00:35:51,760
Speaker 2: to form planets. So we think that gas planets formed

788
00:35:51,760 --> 00:35:54,759
Speaker 2: before the gas disc actually evaporated, sometimes in like the

789
00:35:54,800 --> 00:35:57,839
Speaker 2: two to ten million year range. But rocky planets take

790
00:35:57,920 --> 00:36:01,120
Speaker 2: longer because the inner Solar system is much hotter and messier,

791
00:36:01,239 --> 00:36:04,120
Speaker 2: is less gas available to form planets and no ice whatsoever,

792
00:36:04,280 --> 00:36:06,800
Speaker 2: So those take like thirty to one hundred million years

793
00:36:06,800 --> 00:36:07,240
Speaker 2: to form.

794
00:36:07,440 --> 00:36:09,319
Speaker 1: Okay, so I think what you're saying is that this

795
00:36:09,400 --> 00:36:12,600
Speaker 1: new model, this rebound model, is saying that we kicked

796
00:36:12,640 --> 00:36:16,520
Speaker 1: off a gassy icy planet a long time ago, before

797
00:36:16,560 --> 00:36:18,600
Speaker 1: we even had Earth and Venus and Mars and the

798
00:36:18,680 --> 00:36:21,160
Speaker 1: rocky planets inside, and that it was due to a

799
00:36:21,200 --> 00:36:23,880
Speaker 1: lot of this gas being blown out of the center.

800
00:36:23,719 --> 00:36:25,839
Speaker 2: Exactly, and as the sort of inner radius of that

801
00:36:25,920 --> 00:36:30,000
Speaker 2: gas passes through these early ice giants and gas planets,

802
00:36:30,120 --> 00:36:33,080
Speaker 2: it triggered that instability. They did their crazy dance with

803
00:36:33,160 --> 00:36:35,680
Speaker 2: Jupiter moving in and the other planets moving out and

804
00:36:35,760 --> 00:36:38,800
Speaker 2: ejected an ice giant planet that left the Solar System,

805
00:36:38,840 --> 00:36:41,800
Speaker 2: And all that happened even before the Earth and Mars

806
00:36:41,840 --> 00:36:44,440
Speaker 2: were formed, so they didn't mess up the formation of

807
00:36:44,480 --> 00:36:46,600
Speaker 2: the Earth and Mars because it was already done by then.

808
00:36:47,000 --> 00:36:49,360
Speaker 1: All right, well, those are both great stories. Now the

809
00:36:49,440 --> 00:36:52,279
Speaker 1: question is can we see the planet that we kicked out?

810
00:36:52,360 --> 00:36:56,640
Speaker 1: Are there lonely dejected planets floating out there in space

811
00:36:56,680 --> 00:36:59,400
Speaker 1: that we can see and maybe identify and track to

812
00:36:59,680 --> 00:37:02,120
Speaker 1: perhaps our Solar System? So let's stick into that, But

813
00:37:02,160 --> 00:37:17,240
Speaker 1: first let's take another quick break. All right, we're asking

814
00:37:17,280 --> 00:37:22,200
Speaker 1: the question, did our Solar system lose a planet or

815
00:37:22,320 --> 00:37:25,520
Speaker 1: I guess shepherd it out peacefully into the cosmos.

816
00:37:26,000 --> 00:37:28,920
Speaker 2: That's the niser model. If anything happened, it sounds like

817
00:37:28,960 --> 00:37:30,759
Speaker 2: we can blame it on the gas giants, Like we

818
00:37:30,760 --> 00:37:33,399
Speaker 2: weren't even around when all of this went down. It's

819
00:37:33,440 --> 00:37:35,440
Speaker 2: just the drama we heard about when we showed up.

820
00:37:35,680 --> 00:37:36,279
Speaker 2: Oh I see.

821
00:37:36,360 --> 00:37:38,719
Speaker 1: It's like, yeah, it's like you're the younger sibling and

822
00:37:38,920 --> 00:37:40,880
Speaker 1: there's all this drama before you were even born.

823
00:37:41,600 --> 00:37:44,279
Speaker 2: Exactly, Like why is everybody so mad? And who is

824
00:37:44,320 --> 00:37:46,839
Speaker 2: this missing sibling everybody's talking about you never met?

825
00:37:47,880 --> 00:37:50,040
Speaker 1: Oh wow, this is just god, this is just turned

826
00:37:50,040 --> 00:37:53,520
Speaker 1: into a Korean drama. I feel like super complicated.

827
00:37:53,080 --> 00:37:55,040
Speaker 2: But it is sort of the story. I mean, what

828
00:37:55,080 --> 00:37:58,680
Speaker 2: we learned from this is that these unstable giant planets,

829
00:37:58,719 --> 00:38:02,200
Speaker 2: the ice giants and the gas basically sculpted the inner

830
00:38:02,200 --> 00:38:05,520
Speaker 2: Solar system. I mean, it didn't disrupt the already formed

831
00:38:05,520 --> 00:38:08,680
Speaker 2: Earth in Mars and Venus, but it created the gravitational

832
00:38:08,719 --> 00:38:11,879
Speaker 2: context for them to form and probably changed how they

833
00:38:11,880 --> 00:38:15,160
Speaker 2: did form, the way younger siblings arrive, and family dramas

834
00:38:15,160 --> 00:38:16,520
Speaker 2: that have existed for years.

835
00:38:17,200 --> 00:38:20,040
Speaker 1: But again, I guess this is just kind of a model, right,

836
00:38:20,239 --> 00:38:22,480
Speaker 1: or sort of a guess to maybe explain some of

837
00:38:22,520 --> 00:38:25,000
Speaker 1: what we see. We don't quite know for sure, right.

838
00:38:24,840 --> 00:38:27,760
Speaker 2: We definitely don't know for sure. We've quibbled before about

839
00:38:27,760 --> 00:38:31,080
Speaker 2: what a guess means. Scientifically, I think we have a model,

840
00:38:31,200 --> 00:38:33,959
Speaker 2: we have some evidence for it, we're never exactly sure.

841
00:38:34,000 --> 00:38:36,200
Speaker 2: I mean, we have not identified a planet and said

842
00:38:36,560 --> 00:38:40,080
Speaker 2: that's our lost planet. It's just easier to explain what

843
00:38:40,120 --> 00:38:42,120
Speaker 2: we see in the universe when you add this to

844
00:38:42,200 --> 00:38:44,360
Speaker 2: the story. But that happens for lots of things, like

845
00:38:44,400 --> 00:38:47,360
Speaker 2: we don't witness the early years of the Earth's formation,

846
00:38:47,760 --> 00:38:50,080
Speaker 2: but we have a pretty detailed story about the formation

847
00:38:50,160 --> 00:38:52,239
Speaker 2: of the Earth based on the patterns of evidence that

848
00:38:52,239 --> 00:38:55,040
Speaker 2: we see in the rocks beneath our feet. And so

849
00:38:55,120 --> 00:38:57,160
Speaker 2: that's a big part of science, is developing a story

850
00:38:57,200 --> 00:38:59,680
Speaker 2: to explain the data, even if you don't directly witness

851
00:38:59,719 --> 00:39:01,480
Speaker 2: all of those events, right, right.

852
00:39:01,360 --> 00:39:03,239
Speaker 1: But I guess what I'm trying to say is that

853
00:39:03,239 --> 00:39:05,200
Speaker 1: we had a pretty good story that seemed to check

854
00:39:05,200 --> 00:39:07,719
Speaker 1: out and make sense before, but then it turned out

855
00:39:07,760 --> 00:39:08,920
Speaker 1: to be not quite correct.

856
00:39:09,000 --> 00:39:11,120
Speaker 2: Yeah, that's true. These stories are always evolving in they're

857
00:39:11,120 --> 00:39:13,839
Speaker 2: getting better, Like we like the nice model, but there

858
00:39:13,880 --> 00:39:16,160
Speaker 2: were some dangling questions about how the Earth and Mars

859
00:39:16,239 --> 00:39:18,360
Speaker 2: survived it. And now we like this new model, the

860
00:39:18,400 --> 00:39:20,920
Speaker 2: rebound model, But there's always going to be dangling questions,

861
00:39:20,960 --> 00:39:22,840
Speaker 2: and somebody's going to come along with a better model

862
00:39:23,000 --> 00:39:25,560
Speaker 2: and maybe tell a different story in five years. It's

863
00:39:25,600 --> 00:39:27,680
Speaker 2: a constantly evolving story.

864
00:39:27,760 --> 00:39:31,840
Speaker 1: I guess. But I wonder if maybe like a smoking

865
00:39:31,880 --> 00:39:34,399
Speaker 1: gun or something to definitely be able to say, like, hey,

866
00:39:34,400 --> 00:39:36,120
Speaker 1: there used to be a planet here in the Solar

867
00:39:36,200 --> 00:39:38,600
Speaker 1: System that we don't have anymore, is to actually maybe

868
00:39:38,680 --> 00:39:41,480
Speaker 1: see this planet that we kicked out or that left

869
00:39:41,520 --> 00:39:44,120
Speaker 1: Liane its own out there in space. Isn't it possible

870
00:39:44,160 --> 00:39:46,239
Speaker 1: that we could see a planet like and track it

871
00:39:46,280 --> 00:39:49,360
Speaker 1: to our Solar system out there beyond our Solar System?

872
00:39:49,480 --> 00:39:52,239
Speaker 2: I suppose it's possible, But we're talking about events that

873
00:39:52,360 --> 00:39:56,240
Speaker 2: happened four billion or more years ago, so that planet

874
00:39:56,320 --> 00:39:59,280
Speaker 2: is pretty far gone by now. If it did leave,

875
00:39:59,440 --> 00:40:01,840
Speaker 2: we can do so of more indirect discoveries, though. We

876
00:40:01,840 --> 00:40:04,560
Speaker 2: can look out and say, are there any rogue planets?

877
00:40:04,880 --> 00:40:06,919
Speaker 2: If this is happening in our Solar System, it should

878
00:40:06,920 --> 00:40:10,160
Speaker 2: be happening in other Solar systems. Shouldn't space be filled

879
00:40:10,239 --> 00:40:14,040
Speaker 2: with these ejected ice giants when it happened in other families,

880
00:40:14,080 --> 00:40:16,280
Speaker 2: not just ours, and we can go and look for those.

881
00:40:17,120 --> 00:40:19,960
Speaker 1: Yeah, we had a whole episode on rogue planets. There

882
00:40:20,040 --> 00:40:22,760
Speaker 1: might be a billions of them out there right exactly.

883
00:40:22,840 --> 00:40:25,360
Speaker 2: We can actually spot some of these using what we

884
00:40:25,400 --> 00:40:28,000
Speaker 2: call micro lensing. If one of these planets out there

885
00:40:28,000 --> 00:40:30,920
Speaker 2: floating between stars, passes in front of a star, like

886
00:40:30,960 --> 00:40:33,800
Speaker 2: a little eclipse, then it'll blink out and actually change

887
00:40:33,840 --> 00:40:36,080
Speaker 2: the way that light bends around the planet. So we

888
00:40:36,120 --> 00:40:39,080
Speaker 2: can use these micro lensing techniques to try to spot them.

889
00:40:39,280 --> 00:40:42,279
Speaker 2: We also have infrared telescopes like the Wise telescope that

890
00:40:42,320 --> 00:40:45,520
Speaker 2: can try to directly image them. These planets don't glow

891
00:40:45,600 --> 00:40:48,320
Speaker 2: in the visible light, but they do have some temperature,

892
00:40:48,360 --> 00:40:51,480
Speaker 2: and everything with the temperature glows in some frequency. These

893
00:40:51,520 --> 00:40:54,520
Speaker 2: would low in infrared, and so it's possible to see them.

894
00:40:54,880 --> 00:40:57,200
Speaker 2: So we have seen a bunch of these rogue planets,

895
00:40:57,640 --> 00:41:00,160
Speaker 2: and so we can estimate that there's like one of

896
00:41:00,200 --> 00:41:02,759
Speaker 2: these things for every star in the galaxy.

897
00:41:03,040 --> 00:41:05,759
Speaker 1: Well, I mean there's ae hundred billion of them right

898
00:41:05,800 --> 00:41:07,200
Speaker 1: in our galaxy.

899
00:41:06,920 --> 00:41:08,920
Speaker 2: Exactly, and we've only spotted a few of them. And

900
00:41:08,960 --> 00:41:11,239
Speaker 2: so the calculation of like how many there are is

901
00:41:11,440 --> 00:41:14,600
Speaker 2: very uncertain. There's a huge extrapolation there, which means a

902
00:41:14,680 --> 00:41:17,960
Speaker 2: huge uncertainty, but we know it's a pretty big number.

903
00:41:17,960 --> 00:41:20,120
Speaker 2: We know it's not just like ten in the galaxy.

904
00:41:20,280 --> 00:41:22,800
Speaker 2: There's lots of these things out there, and that lends

905
00:41:22,840 --> 00:41:25,800
Speaker 2: credence to this story that, like when solar systems form,

906
00:41:26,239 --> 00:41:29,200
Speaker 2: there's a period of instability when big planets can get

907
00:41:29,280 --> 00:41:29,799
Speaker 2: thrown out.

908
00:41:30,400 --> 00:41:32,400
Speaker 1: So we've actually seen these like if you look at

909
00:41:32,400 --> 00:41:33,880
Speaker 1: a picture of the nice guy in the infrared, you

910
00:41:33,880 --> 00:41:36,120
Speaker 1: can see these thoughts moving across the sky.

911
00:41:36,320 --> 00:41:38,479
Speaker 2: We can actually see these planets, and we have seen

912
00:41:38,600 --> 00:41:41,400
Speaker 2: with direct imaging some of these rogue planets. Again, not

913
00:41:41,600 --> 00:41:44,239
Speaker 2: very many, and so we're extrapolating from a handful up

914
00:41:44,239 --> 00:41:47,040
Speaker 2: to a big number. We've definitely seen non zero and

915
00:41:47,160 --> 00:41:51,319
Speaker 2: very recently James Webb saw some really crazy stuff out there.

916
00:41:51,360 --> 00:41:55,440
Speaker 2: They found these Jupiter mass binary objects. They call them jumbos.

917
00:41:55,480 --> 00:41:58,200
Speaker 2: These are pairs of planets floating out there in the

918
00:41:58,239 --> 00:42:00,279
Speaker 2: galaxy with no star near by.

919
00:42:00,600 --> 00:42:02,640
Speaker 1: Wait what, well, first of all, James Webb, you mean

920
00:42:02,680 --> 00:42:06,960
Speaker 1: the telescope right, Yes, not James web from Erie, Pennsylvania.

921
00:42:07,719 --> 00:42:10,440
Speaker 2: We did not exhume the previous NASA administrator and ask

922
00:42:10,520 --> 00:42:12,200
Speaker 2: him to look at the night sky and then write

923
00:42:12,200 --> 00:42:14,279
Speaker 2: down with what he said. Though that would make a

924
00:42:14,280 --> 00:42:15,960
Speaker 2: pretty cool graphic novel. Yeah.

925
00:42:16,040 --> 00:42:17,799
Speaker 1: Yeah, Well, I just don't want to assume everyone knows

926
00:42:17,840 --> 00:42:18,839
Speaker 1: what James Webb is.

927
00:42:19,560 --> 00:42:22,160
Speaker 2: No, you're exactly right. The James web Space Telescope a

928
00:42:22,280 --> 00:42:24,239
Speaker 2: very powerful device that we launched a couple of years

929
00:42:24,280 --> 00:42:27,600
Speaker 2: ago and is an infrared telescope capable of seeing things

930
00:42:27,640 --> 00:42:32,719
Speaker 2: that are pretty cold. Spotted forty two pairs of jumbos.

931
00:42:32,520 --> 00:42:35,359
Speaker 1: WHOA and so is there? Is it weird that they're

932
00:42:35,360 --> 00:42:37,879
Speaker 1: in pairs? Or does it feel normal that they're in pairs? Meaning?

933
00:42:38,160 --> 00:42:40,080
Speaker 1: Does that mean that they were ejective from their Solar

934
00:42:40,120 --> 00:42:43,280
Speaker 1: system in pairs like they left together.

935
00:42:43,480 --> 00:42:45,960
Speaker 2: It's a great question. We don't know the answer to that.

936
00:42:46,000 --> 00:42:50,120
Speaker 2: Simulations suggest that it's unlikely for big planets to leave

937
00:42:50,160 --> 00:42:52,759
Speaker 2: the Solar system together, right. They would have to be

938
00:42:52,840 --> 00:42:55,800
Speaker 2: like bound together and then leave together, which means that

939
00:42:55,840 --> 00:42:58,520
Speaker 2: their fragile orbits around each other would have survived very

940
00:42:58,600 --> 00:43:03,600
Speaker 2: chaotic period. Seems very unlikely. So these are rogue planets

941
00:43:03,600 --> 00:43:05,359
Speaker 2: that are out there without their star, but they don't

942
00:43:05,400 --> 00:43:08,360
Speaker 2: seem to have been ejected from solar systems. So it

943
00:43:08,440 --> 00:43:10,520
Speaker 2: just sort of like adds to the murkiness of what's

944
00:43:10,520 --> 00:43:12,040
Speaker 2: going on with rogue planets.

945
00:43:12,320 --> 00:43:14,600
Speaker 1: Whoa wait, wait, so maybe they were ejected and then

946
00:43:14,640 --> 00:43:17,400
Speaker 1: they met up with another jumbo out there in space.

947
00:43:18,200 --> 00:43:20,680
Speaker 2: We actually don't have a great story to explain how

948
00:43:20,680 --> 00:43:24,040
Speaker 2: these even exist. Like that seems very unlikely for all

949
00:43:24,080 --> 00:43:26,799
Speaker 2: these jupiters to like start dancing around each other just

950
00:43:26,880 --> 00:43:27,400
Speaker 2: in space.

951
00:43:27,600 --> 00:43:30,080
Speaker 1: Well, maybe they have like a planet dating app or something.

952
00:43:31,640 --> 00:43:34,320
Speaker 2: Maybe they're speed dating there, or they're square dancing or something.

953
00:43:34,440 --> 00:43:35,600
Speaker 2: They're all changing partners.

954
00:43:35,920 --> 00:43:38,760
Speaker 1: That's right, they have jumpler under phones.

955
00:43:39,760 --> 00:43:42,480
Speaker 2: Some people suggested maybe they just formed independently, like you

956
00:43:42,520 --> 00:43:44,800
Speaker 2: had a solar system and it didn't have enough stuff

957
00:43:45,040 --> 00:43:46,840
Speaker 2: to actually have a star. You just got a couple

958
00:43:46,840 --> 00:43:49,200
Speaker 2: of jupiters. But we think that there's like a minimum

959
00:43:49,280 --> 00:43:51,759
Speaker 2: amount of mass you need to get like your own

960
00:43:51,800 --> 00:43:54,000
Speaker 2: solar system, otherwise you just get slurped up in like

961
00:43:54,000 --> 00:43:57,800
Speaker 2: a neighboring solar system when that huge stellar nurseries breaking

962
00:43:57,880 --> 00:44:00,480
Speaker 2: up into chunks that form solar systems. So we think

963
00:44:00,480 --> 00:44:03,000
Speaker 2: that these things are probably too small to have seeded

964
00:44:03,040 --> 00:44:05,960
Speaker 2: their own structure and be their own solar system. We

965
00:44:06,000 --> 00:44:08,760
Speaker 2: don't think they could have been ejected from other solar systems.

966
00:44:08,960 --> 00:44:11,319
Speaker 2: So it's something of a question of where these came from,

967
00:44:11,400 --> 00:44:13,279
Speaker 2: you know, just to paint the picture that like, there's

968
00:44:13,320 --> 00:44:14,880
Speaker 2: a lot we still don't know. There's a lot of

969
00:44:14,880 --> 00:44:15,719
Speaker 2: guessing going on.

970
00:44:16,080 --> 00:44:19,280
Speaker 1: But I guess if they didn't come from a solar system,

971
00:44:19,480 --> 00:44:21,840
Speaker 1: then that doesn't really tell us anything about this idea

972
00:44:21,840 --> 00:44:25,800
Speaker 1: of how often solar systems kick out planets exactly.

973
00:44:25,840 --> 00:44:28,400
Speaker 2: But it adds doubt to the argument that because we

974
00:44:28,440 --> 00:44:31,400
Speaker 2: see a bunch of rogue planets out there that suggest

975
00:44:31,480 --> 00:44:33,799
Speaker 2: that planets are lost from solar systems, because there are

976
00:44:33,840 --> 00:44:36,719
Speaker 2: planets out there whose formations we just don't understand and

977
00:44:36,719 --> 00:44:38,680
Speaker 2: we think don't come from having been lost by a

978
00:44:38,680 --> 00:44:39,320
Speaker 2: solar system.

979
00:44:39,400 --> 00:44:41,120
Speaker 1: All right, well, I guess to answer the question of

980
00:44:41,160 --> 00:44:43,840
Speaker 1: the episode, has our solar system lost any planets? The

981
00:44:43,960 --> 00:44:50,399
Speaker 1: answer is maybe, we guess. So we guess. Maybe we

982
00:44:50,480 --> 00:44:53,680
Speaker 1: used to have a brother, an older brother, but now

983
00:44:53,840 --> 00:44:56,680
Speaker 1: nobody likes to talk about him or her, and it's

984
00:44:56,800 --> 00:45:00,520
Speaker 1: very awkward. It makes all the models break, all the

985
00:45:00,520 --> 00:45:01,560
Speaker 1: pets are uncomfortable.

986
00:45:01,680 --> 00:45:03,680
Speaker 2: Almost all of the models we use to explain the

987
00:45:03,680 --> 00:45:07,920
Speaker 2: solar system do have an additional planet. It's not absolutely required.

988
00:45:08,200 --> 00:45:10,960
Speaker 2: It's possible to explain the Solar System without an additional

989
00:45:11,040 --> 00:45:14,200
Speaker 2: planet that got ejected during one of these early instabilities.

990
00:45:14,520 --> 00:45:17,040
Speaker 2: But it just makes the story come together more crisply.

991
00:45:17,080 --> 00:45:19,440
Speaker 2: It makes our Solar system seem less unlikely.

992
00:45:19,760 --> 00:45:21,600
Speaker 1: Now, how does this match up with I know there

993
00:45:21,640 --> 00:45:24,160
Speaker 1: are scientists that think that we have maybe a ninth

994
00:45:24,200 --> 00:45:26,640
Speaker 1: planet in our Solar system. We just can see it

995
00:45:27,120 --> 00:45:27,960
Speaker 1: planet X, right.

996
00:45:28,160 --> 00:45:30,640
Speaker 2: Yeah, there are some people who look at like gravitational

997
00:45:30,640 --> 00:45:33,040
Speaker 2: aberrations in the orbits of our planet to see if

998
00:45:33,040 --> 00:45:35,600
Speaker 2: there's something else out there tugging on it. But there's

999
00:45:35,640 --> 00:45:38,320
Speaker 2: no conclusive evidence for that. It's like very very gentle,

1000
00:45:38,640 --> 00:45:40,759
Speaker 2: and there's a lot of disagreement about whether it's just

1001
00:45:40,880 --> 00:45:42,640
Speaker 2: noise or has other explanations.

1002
00:45:42,719 --> 00:45:45,000
Speaker 1: It's almost sort of the same, right, They use simulations

1003
00:45:45,040 --> 00:45:47,480
Speaker 1: and try to figure out what would best explain what

1004
00:45:47,520 --> 00:45:48,000
Speaker 1: we have now.

1005
00:45:48,080 --> 00:45:50,600
Speaker 2: Yeah, exactly, but the data there are not conclusive.

1006
00:45:50,880 --> 00:45:54,040
Speaker 1: All right. Well, another interesting lesson to keep track of

1007
00:45:54,040 --> 00:45:56,520
Speaker 1: your planets. Don't lose them because once they're gone, they're

1008
00:45:56,520 --> 00:45:57,120
Speaker 1: gone forever.

1009
00:45:57,400 --> 00:45:59,480
Speaker 2: And try to understand where you came from and what's

1010
00:45:59,480 --> 00:46:02,440
Speaker 2: your contact is, what happened before you showed up on

1011
00:46:02,480 --> 00:46:03,000
Speaker 2: the scene.

1012
00:46:03,120 --> 00:46:05,880
Speaker 1: Yeah, well, not that we have much influence over what happens,

1013
00:46:05,920 --> 00:46:07,719
Speaker 1: but it's interesting to think about what might happen in

1014
00:46:07,719 --> 00:46:10,000
Speaker 1: the future, Like, is it possible that the Earth might

1015
00:46:10,040 --> 00:46:13,000
Speaker 1: get kicked out of the Solar System right in the

1016
00:46:13,000 --> 00:46:13,800
Speaker 1: future exactly?

1017
00:46:13,880 --> 00:46:16,480
Speaker 2: The difference between these models tells a very different story.

1018
00:46:16,600 --> 00:46:20,040
Speaker 2: If it really is lots of gentle tugs from planet Esimals, well,

1019
00:46:20,040 --> 00:46:21,560
Speaker 2: that could still happen in the future. We have the

1020
00:46:21,680 --> 00:46:24,200
Speaker 2: Orc Cloud, we have the Kuyper Belt. There's still tugging

1021
00:46:24,320 --> 00:46:27,360
Speaker 2: going on. But if it was something that only happened

1022
00:46:27,360 --> 00:46:30,000
Speaker 2: in the very early formation of the Solar System itself,

1023
00:46:30,160 --> 00:46:32,799
Speaker 2: as this gas was pushed out, that's not something that's

1024
00:46:32,880 --> 00:46:35,799
Speaker 2: likely to be reproduced, and so that level of instability

1025
00:46:35,800 --> 00:46:37,200
Speaker 2: is probably not going to happen again.

1026
00:46:37,320 --> 00:46:40,080
Speaker 1: Now, Daniel, if we did have an icy gas planet before,

1027
00:46:40,760 --> 00:46:42,759
Speaker 1: but it was filled with white chocolate, are you happy

1028
00:46:42,840 --> 00:46:45,080
Speaker 1: that it's gone or are you sad that we don't

1029
00:46:45,080 --> 00:46:45,640
Speaker 1: have anymore?

1030
00:46:45,719 --> 00:46:47,600
Speaker 2: No, it's bittersweet. I wish it's the best.

1031
00:46:48,760 --> 00:46:51,000
Speaker 1: No, it's not bitter, it's sweet. It's white chocolate. That's

1032
00:46:51,000 --> 00:46:52,240
Speaker 1: the whole point of white chocolate.

1033
00:46:53,320 --> 00:46:54,960
Speaker 2: It's oversweetened. That's the problem.

1034
00:46:55,080 --> 00:46:56,439
Speaker 1: But maybe it'd be good for you because it would

1035
00:46:56,480 --> 00:46:59,000
Speaker 1: make all the white chocolate lovers go to this planet

1036
00:46:59,120 --> 00:47:00,560
Speaker 1: and leave ours exactly.

1037
00:47:00,680 --> 00:47:04,160
Speaker 2: Let's arrange transit to the frozen planet of white chocolate.

1038
00:47:04,280 --> 00:47:05,240
Speaker 1: Well call it white.

1039
00:47:07,120 --> 00:47:08,000
Speaker 2: No son of mine?

1040
00:47:10,239 --> 00:47:12,279
Speaker 1: All right, Well, we hope you enjoyed that. Thanks for

1041
00:47:12,360 --> 00:47:14,520
Speaker 1: joining us, See you next time.

1042
00:47:19,080 --> 00:47:22,280
Speaker 2: For more science and curiosity, come find us on social media,

1043
00:47:22,360 --> 00:47:26,920
Speaker 2: where we answer questions and post videos. We're on Twitter, Discord, Instant,

1044
00:47:27,000 --> 00:47:30,440
Speaker 2: and now TikTok. Thanks for listening, and remember that Daniel

1045
00:47:30,480 --> 00:47:33,920
Speaker 2: and Jorge Explain the Universe is a production of iHeartRadio.

1046
00:47:34,200 --> 00:47:39,359
Speaker 2: For more podcasts from iHeartRadio, visit the iHeartRadio app, Apple Podcasts,

1047
00:47:39,480 --> 00:47:41,840
Speaker 2: or wherever you listen to your favorite shows.