1
00:00:07,960 --> 00:00:09,800
Speaker 1: Hey, Daniel, I have a new idea for how to

2
00:00:09,880 --> 00:00:11,480
Speaker 1: solve quantum gravity.

3
00:00:11,680 --> 00:00:13,800
Speaker 2: Oh my gosh, I'm so excited. I can't wait to

4
00:00:13,800 --> 00:00:14,080
Speaker 2: hear it.

5
00:00:14,320 --> 00:00:17,400
Speaker 1: Okay, just take any everyday object and add the word

6
00:00:17,560 --> 00:00:19,000
Speaker 1: theory to the end of it.

7
00:00:19,440 --> 00:00:20,239
Speaker 2: What that's it?

8
00:00:20,760 --> 00:00:20,840
Speaker 3: Like?

9
00:00:21,000 --> 00:00:21,680
Speaker 2: How did that work?

10
00:00:21,840 --> 00:00:25,840
Speaker 1: You know? Like string theory or loop theory. Boom, I've

11
00:00:25,920 --> 00:00:26,960
Speaker 1: solved quantum gravity.

12
00:00:27,120 --> 00:00:29,320
Speaker 2: Those are already theories of quantum graphy.

13
00:00:30,560 --> 00:00:33,760
Speaker 1: Okay, there are other objects we can use, like table

14
00:00:33,800 --> 00:00:39,360
Speaker 1: theory or rug theory or pokemon theory. Boom. Anyone can

15
00:00:39,400 --> 00:00:41,200
Speaker 1: be a quantum gravity physicist.

16
00:00:41,680 --> 00:00:43,559
Speaker 2: Oh, I wish that's all there was to it.

17
00:00:43,840 --> 00:00:44,600
Speaker 1: Wait, there's more.

18
00:00:44,720 --> 00:00:47,960
Speaker 2: Physics isn't just about naming things, man, though, that is

19
00:00:48,000 --> 00:00:48,680
Speaker 2: the hardest part.

20
00:01:04,000 --> 00:01:06,800
Speaker 1: II am Foehammer, cartoonist and the author of Oliver's Great

21
00:01:06,800 --> 00:01:07,520
Speaker 1: Big Universe.

22
00:01:07,800 --> 00:01:10,679
Speaker 2: Hi. I'm Daniel. I'm a particle physicist and a professor

23
00:01:10,760 --> 00:01:13,319
Speaker 2: at UC Irvine, and I hope that I'm around when

24
00:01:13,360 --> 00:01:15,000
Speaker 2: quanm gravity gets figured out.

25
00:01:15,360 --> 00:01:18,679
Speaker 1: Well, that's a massive wish. It's a little bit heavy

26
00:01:18,800 --> 00:01:20,640
Speaker 1: on the responsibility for a theorists.

27
00:01:22,280 --> 00:01:23,679
Speaker 2: I just want to be around so that I can

28
00:01:23,720 --> 00:01:25,200
Speaker 2: hear what name you give it?

29
00:01:26,040 --> 00:01:27,960
Speaker 1: It feels a little lazy of you. You're like, I

30
00:01:28,000 --> 00:01:30,240
Speaker 1: wish that somebody else would solve this problem for me.

31
00:01:30,920 --> 00:01:32,840
Speaker 1: When did you just get down to it, Daniel and

32
00:01:32,880 --> 00:01:33,600
Speaker 1: solve it yourself.

33
00:01:33,760 --> 00:01:37,080
Speaker 2: Not my job, man, not my job. I'm an experimentalist.

34
00:01:37,240 --> 00:01:38,360
Speaker 1: I so you're a physicist.

35
00:01:39,080 --> 00:01:41,399
Speaker 2: There are different flavors of physicists, you know, And I'm

36
00:01:41,400 --> 00:01:44,560
Speaker 2: an experimentalist. I go out and discover weird stuff nobody

37
00:01:44,600 --> 00:01:47,560
Speaker 2: can explain, and theorists job is to come up with

38
00:01:47,600 --> 00:01:48,600
Speaker 2: ways to explain it.

39
00:01:48,720 --> 00:01:52,200
Speaker 1: I feel like you're letting these imaginary or artificial boundaries

40
00:01:52,240 --> 00:01:55,320
Speaker 1: get in the way of your true dreams. Daniel. Like,

41
00:01:55,440 --> 00:01:57,480
Speaker 1: imagine if a serious said, oh, man, I wish I

42
00:01:57,520 --> 00:02:00,680
Speaker 1: was an experimental physicist and could press but and stuff.

43
00:02:00,840 --> 00:02:03,040
Speaker 1: Wouldn't you just be like, just press the button.

44
00:02:03,320 --> 00:02:05,640
Speaker 2: No, No, you're right, those boundaries are artificial. Here in

45
00:02:05,720 --> 00:02:08,519
Speaker 2: my department we have a theoretical physicist who's now running

46
00:02:08,520 --> 00:02:11,359
Speaker 2: his whole experiment. And last year I wrote quite a

47
00:02:11,400 --> 00:02:15,440
Speaker 2: few theory papers. So you're right, I'm cowering behind categories.

48
00:02:15,040 --> 00:02:17,440
Speaker 1: That this could be you, Daniel. Just make up a

49
00:02:17,480 --> 00:02:19,840
Speaker 1: theory and you can call yourself a theorist. Isn't that

50
00:02:19,840 --> 00:02:20,440
Speaker 1: how it works.

51
00:02:21,160 --> 00:02:23,400
Speaker 2: Yeah, podcast Theory of Physics.

52
00:02:23,040 --> 00:02:26,680
Speaker 1: Dan, Yeah, Like, what's the minimum like in your department?

53
00:02:26,760 --> 00:02:28,919
Speaker 1: Is there a minimum number of theories you have to

54
00:02:28,919 --> 00:02:31,200
Speaker 1: come up with to be a theorist or number of

55
00:02:31,200 --> 00:02:32,560
Speaker 1: publications one?

56
00:02:33,040 --> 00:02:35,040
Speaker 2: Just one there? You have to do it once.

57
00:02:35,000 --> 00:02:39,720
Speaker 1: That you can be a theorizer Today in this podcast,

58
00:02:39,960 --> 00:02:41,920
Speaker 1: what's your theory of everything? Daniel mm?

59
00:02:42,360 --> 00:02:44,640
Speaker 2: Yeah, I think it's the chocolate theory of everything.

60
00:02:45,960 --> 00:02:49,959
Speaker 1: It's a dark theory or is it a white theory?

61
00:02:50,880 --> 00:02:52,680
Speaker 2: I hope it's not a white theory. Oh my gosh,

62
00:02:52,760 --> 00:02:54,520
Speaker 2: I'd be so disappointed in the universe.

63
00:02:56,720 --> 00:03:00,320
Speaker 1: Turns out white chocolate is the secret to everything, and

64
00:03:00,360 --> 00:03:01,480
Speaker 1: so you're going to just check.

65
00:03:01,320 --> 00:03:04,000
Speaker 2: Out sweet and bitter at the same time.

66
00:03:04,440 --> 00:03:06,600
Speaker 1: No, that's the whole point of white chocolate. It's not bitter.

67
00:03:07,639 --> 00:03:09,560
Speaker 1: It's sweet for everybody.

68
00:03:09,360 --> 00:03:13,560
Speaker 2: White chocolate sweet. But I would be bitter, just you.

69
00:03:16,600 --> 00:03:19,320
Speaker 1: But anyways, welcome to our podcast, Daniel and Jorge Explain

70
00:03:19,360 --> 00:03:22,200
Speaker 1: the Universe, a production of iHeartRadio.

71
00:03:21,639 --> 00:03:24,400
Speaker 2: In which we do our best to understand this sweet,

72
00:03:24,400 --> 00:03:28,079
Speaker 2: sweet universe without getting bitter about our favorite theories. We

73
00:03:28,240 --> 00:03:30,320
Speaker 2: hope that everything that's out there in the universe, the

74
00:03:30,360 --> 00:03:34,279
Speaker 2: tiny particles the huge black holes, the swirling oceans of magma.

75
00:03:34,360 --> 00:03:37,559
Speaker 2: All of those things can be explained, can be understood,

76
00:03:37,800 --> 00:03:39,680
Speaker 2: and we try to talk about all of them here

77
00:03:39,800 --> 00:03:42,040
Speaker 2: on the podcast, where our goal is to fit all

78
00:03:42,040 --> 00:03:43,840
Speaker 2: of those theories into your brain.

79
00:03:44,160 --> 00:03:46,560
Speaker 1: That's right, because it is a sweet universe. It's also

80
00:03:46,640 --> 00:03:50,160
Speaker 1: a sour universe, a bitter universe, and assault the universe

81
00:03:50,200 --> 00:03:53,880
Speaker 1: and a umami universe. It's got all the flavors of

82
00:03:53,960 --> 00:03:57,120
Speaker 1: mysteries and unknowns and questions that we can ask of it,

83
00:03:57,160 --> 00:03:59,160
Speaker 1: and here on the podcast we sometimes try to answer

84
00:03:59,240 --> 00:03:59,840
Speaker 1: those questions.

85
00:04:00,040 --> 00:04:02,440
Speaker 2: That's right, Like string theory can explain the fundamental forces,

86
00:04:02,640 --> 00:04:04,680
Speaker 2: but can it explain why people drink.

87
00:04:04,520 --> 00:04:08,920
Speaker 1: Boba because it tastes sweet? I guess it's not bitter,

88
00:04:09,320 --> 00:04:12,560
Speaker 1: doesn't have a mommy. I don't think it's truly and delicious.

89
00:04:12,560 --> 00:04:14,720
Speaker 1: I mean, what's not to like? Isn't that the whole

90
00:04:14,720 --> 00:04:17,280
Speaker 1: point of the universe to be truly and delicious?

91
00:04:17,640 --> 00:04:19,720
Speaker 2: What's not to like the feeling of choking as you're

92
00:04:19,720 --> 00:04:20,880
Speaker 2: trying to enjoy a beverage?

93
00:04:21,000 --> 00:04:22,440
Speaker 1: I keep saying this time, but I feel like you're

94
00:04:22,440 --> 00:04:25,520
Speaker 1: not drinking boba correctly. If somebody needs to show you

95
00:04:25,600 --> 00:04:27,880
Speaker 1: the true theory of boba drinking.

96
00:04:28,000 --> 00:04:30,080
Speaker 2: No, I know how to drink boba. You take the boba,

97
00:04:30,240 --> 00:04:31,760
Speaker 2: you throw it in the trash, you move on with

98
00:04:31,800 --> 00:04:32,239
Speaker 2: your life.

99
00:04:32,360 --> 00:04:36,560
Speaker 1: Then you're that's not technically drinking, Danielle. Maybe maybe that's

100
00:04:36,560 --> 00:04:39,600
Speaker 1: why you're not a theory. You don't know how to

101
00:04:39,720 --> 00:04:40,599
Speaker 1: formerly theories.

102
00:04:40,680 --> 00:04:43,320
Speaker 2: I'm generalizing drink. I have a new theory of drinking.

103
00:04:46,120 --> 00:04:47,840
Speaker 2: Teach me, teach me a wise one.

104
00:04:47,920 --> 00:04:49,760
Speaker 1: I'm not sure how we got to Boba's, but anyways,

105
00:04:49,760 --> 00:04:52,800
Speaker 1: it is a wonderful universe, full of interesting mysteries and

106
00:04:52,839 --> 00:04:55,040
Speaker 1: lots of interesting questions that you can ask of it,

107
00:04:55,360 --> 00:04:57,760
Speaker 1: and that anyone can ask of it, even our listeners.

108
00:04:57,960 --> 00:05:00,680
Speaker 2: Because science is not just about satisfying the curiosity of

109
00:05:00,680 --> 00:05:03,000
Speaker 2: people who are paid to come up with theories or

110
00:05:03,040 --> 00:05:07,120
Speaker 2: to do experiments or to fuzz those boundaries, but everybody

111
00:05:07,160 --> 00:05:10,839
Speaker 2: out there. It's powered by human curiosity. It is fundamental

112
00:05:10,880 --> 00:05:14,159
Speaker 2: desire to understand the nature of the universe we live in,

113
00:05:14,240 --> 00:05:18,040
Speaker 2: to make it make sense. And so we encourage everybody

114
00:05:18,040 --> 00:05:20,840
Speaker 2: out there to ask questions about how the universe works,

115
00:05:20,880 --> 00:05:23,320
Speaker 2: try to fit all those various pieces together into their mind,

116
00:05:23,640 --> 00:05:26,000
Speaker 2: and when they don't make sense, to write to us

117
00:05:26,160 --> 00:05:30,080
Speaker 2: to questions at Danielanjorgey dot com, where every question gets

118
00:05:30,080 --> 00:05:30,440
Speaker 2: an answer.

119
00:05:30,520 --> 00:05:32,440
Speaker 1: That's right. Everybody has answers, and it seems like the

120
00:05:32,440 --> 00:05:34,680
Speaker 1: more you learn about the universe, the more questions you

121
00:05:34,760 --> 00:05:37,560
Speaker 1: have of it. And sometimes on this podcast we like

122
00:05:37,600 --> 00:05:38,840
Speaker 1: to answer some of those questions.

123
00:05:38,920 --> 00:05:40,680
Speaker 2: That's right. If you send me a question and I think, hm,

124
00:05:40,760 --> 00:05:42,279
Speaker 2: I bet a lot of people want to hear the

125
00:05:42,320 --> 00:05:45,000
Speaker 2: answer to that one, then we'll play for everybody on

126
00:05:45,040 --> 00:05:46,960
Speaker 2: the podcast and even answer it.

127
00:05:47,000 --> 00:05:54,080
Speaker 1: So to the on the podcast, we'll be tackling listener

128
00:05:54,200 --> 00:05:58,200
Speaker 1: questions number fifty four. Is this like the studio fifty

129
00:05:58,200 --> 00:06:00,919
Speaker 1: four version? Are we going to rock out and do

130
00:06:01,040 --> 00:06:02,039
Speaker 1: a lot of drugs?

131
00:06:03,520 --> 00:06:04,919
Speaker 2: I hope you're wearing something appropriate?

132
00:06:05,080 --> 00:06:07,800
Speaker 1: Oh yeah, yeah, yeah, no, I'm always fashionable, Daniel. You

133
00:06:07,839 --> 00:06:08,760
Speaker 1: don't even have to ask.

134
00:06:09,560 --> 00:06:11,840
Speaker 2: Do you have your Studio fifty four pajamas on? Right now?

135
00:06:12,040 --> 00:06:14,640
Speaker 1: I got my Studio fifty four cargo pants on and

136
00:06:14,760 --> 00:06:19,719
Speaker 1: my Studio fifty four hoodie on? And what else do

137
00:06:19,720 --> 00:06:20,039
Speaker 1: you need?

138
00:06:20,360 --> 00:06:22,159
Speaker 2: Hmm? It sounds like you're kind of dressed the way

139
00:06:22,160 --> 00:06:22,880
Speaker 2: you normally are.

140
00:06:23,640 --> 00:06:27,640
Speaker 1: Yeah. I live in the eighties. I live the glaboral

141
00:06:27,640 --> 00:06:29,799
Speaker 1: life of the eighties every day shooting we all.

142
00:06:29,839 --> 00:06:31,800
Speaker 2: You found the perfect uniform and you're sticking with it.

143
00:06:31,839 --> 00:06:33,359
Speaker 1: They stopped changing closing the eighties.

144
00:06:33,800 --> 00:06:37,640
Speaker 2: Yes, and now you literally couldn't get them off once.

145
00:06:37,680 --> 00:06:39,920
Speaker 1: I like something, there's no need to change in right.

146
00:06:39,960 --> 00:06:42,920
Speaker 2: That's right. And what I like are hearing questions from

147
00:06:43,040 --> 00:06:46,080
Speaker 2: listeners wondering what people out there do and do not

148
00:06:46,360 --> 00:06:49,760
Speaker 2: understand about our universe. Sometimes people hear something on the

149
00:06:49,760 --> 00:06:51,680
Speaker 2: podcast that doesn't make sense to them, then they write

150
00:06:51,680 --> 00:06:53,919
Speaker 2: to me, or they read some other crazy article that

151
00:06:54,000 --> 00:06:57,120
Speaker 2: doesn't quite fit in their brain, or they're just thinking

152
00:06:57,160 --> 00:07:00,159
Speaker 2: deeply about the universe. Thanks everybody who writes in with

153
00:07:00,200 --> 00:07:00,800
Speaker 2: your questions.

154
00:07:00,920 --> 00:07:03,839
Speaker 1: Yeah, and so today we have three awesome questions from listeners.

155
00:07:04,200 --> 00:07:08,320
Speaker 1: We have questions here about string theory, cosmic strings, and

156
00:07:08,520 --> 00:07:11,840
Speaker 1: something that is not strings, but maybe aliens.

157
00:07:12,040 --> 00:07:13,920
Speaker 2: Are you saying aliens couldn't be made of strings?

158
00:07:14,200 --> 00:07:16,400
Speaker 1: Why do you want to string the listener along here

159
00:07:16,440 --> 00:07:20,120
Speaker 1: and pretend that there's a connection between it and all

160
00:07:20,200 --> 00:07:21,680
Speaker 1: of these questions.

161
00:07:22,200 --> 00:07:23,679
Speaker 2: We'll find it. We'll find the connection.

162
00:07:23,920 --> 00:07:25,760
Speaker 1: I'm sure there are aliens. They use strings. I mean

163
00:07:25,760 --> 00:07:28,880
Speaker 1: they have to wear clothes. I guess maybe to they

164
00:07:29,040 --> 00:07:32,560
Speaker 1: and for that they need strings, right, I know, yeah, yeah,

165
00:07:32,600 --> 00:07:35,119
Speaker 1: Well let's jump right into it, Daniel. Our first question

166
00:07:35,200 --> 00:07:38,560
Speaker 1: comes from Bruce and he has a question about string

167
00:07:38,600 --> 00:07:40,119
Speaker 1: theory in The Big Bang.

168
00:07:40,800 --> 00:07:47,880
Speaker 4: Hello Daniel and Jorey Burce labastered here from Lettingham, Saskatchewan, Canada.

169
00:07:48,120 --> 00:07:52,119
Speaker 4: I was just wondering about string theory and the Big Bang?

170
00:07:53,240 --> 00:07:57,200
Speaker 4: Is there any series around string theory and the Big Bank?

171
00:07:58,640 --> 00:08:02,560
Speaker 4: If I understand correctly, the specific vibration of the strings

172
00:08:02,680 --> 00:08:07,960
Speaker 4: creates specific particles. I'm thinking on the frequency of the

173
00:08:08,000 --> 00:08:13,640
Speaker 4: strings that are everywhere changing to suddenly create the universe,

174
00:08:13,800 --> 00:08:18,520
Speaker 4: and the particles sort of like they decayed down to

175
00:08:18,720 --> 00:08:24,040
Speaker 4: the right energy level to create particles. Once again, you

176
00:08:24,080 --> 00:08:29,000
Speaker 4: guys are awesome. Everything you do is great and I

177
00:08:29,200 --> 00:08:30,400
Speaker 4: look forward to your answer.

178
00:08:31,000 --> 00:08:33,560
Speaker 1: All right. This feels like taking two big questions and

179
00:08:33,600 --> 00:08:37,679
Speaker 1: smushing them into one ginormous question or a little tiny question,

180
00:08:37,800 --> 00:08:39,240
Speaker 1: depending on your perspective.

181
00:08:40,559 --> 00:08:43,080
Speaker 2: No, I think it's a really cool question. It's trying

182
00:08:43,120 --> 00:08:46,240
Speaker 2: to understand whether string theory gives us an idea of

183
00:08:46,280 --> 00:08:49,280
Speaker 2: where the universe comes from and how we all ended

184
00:08:49,360 --> 00:08:51,920
Speaker 2: up where we are hating or loving Buba?

185
00:08:52,240 --> 00:08:57,120
Speaker 1: Boy, you really have it against Ba. What did Bulba

186
00:08:57,200 --> 00:08:59,280
Speaker 1: do to you, Diana, did it actually try to choke you?

187
00:08:59,600 --> 00:09:01,760
Speaker 2: Yes, the first time I had Boba, I almost choked

188
00:09:01,800 --> 00:09:04,160
Speaker 2: on one. Yes, absolutely, and I will never forgive it.

189
00:09:07,520 --> 00:09:09,800
Speaker 1: Well, it sounds more like the user error here than

190
00:09:10,080 --> 00:09:11,640
Speaker 1: a fault of the product.

191
00:09:11,600 --> 00:09:13,960
Speaker 2: To be honest, fair, fair, You know, we're talking about

192
00:09:14,040 --> 00:09:16,240
Speaker 2: quantum gravity. In the last episode we had about it,

193
00:09:16,440 --> 00:09:19,200
Speaker 2: we interviewed Nathan, who likes Boba even though his dad

194
00:09:19,280 --> 00:09:21,480
Speaker 2: hates it. So that was just running through my mind.

195
00:09:21,760 --> 00:09:24,160
Speaker 1: I see, I see, it's really stuck on your head.

196
00:09:27,559 --> 00:09:30,040
Speaker 1: But there's a connection right the Big Bang in Boba.

197
00:09:30,480 --> 00:09:33,520
Speaker 1: It's a little like fuzzy ball right at some point.

198
00:09:34,280 --> 00:09:36,520
Speaker 2: Yes, it's dark, mysterious and kind of dangerous.

199
00:09:36,520 --> 00:09:39,360
Speaker 1: And you can string Boba's long into to make a

200
00:09:39,600 --> 00:09:41,040
Speaker 1: Boba pearl necklace.

201
00:09:42,080 --> 00:09:44,280
Speaker 2: Boba's got two bes in it, just like the Big Bang.

202
00:09:44,760 --> 00:09:47,520
Speaker 1: I think Boba's one word, Mmmm, it's got two b's

203
00:09:47,559 --> 00:09:51,760
Speaker 1: in it. Though, I see this word has two bees,

204
00:09:51,920 --> 00:09:53,800
Speaker 1: just like these two other two words have two bees.

205
00:09:53,880 --> 00:09:54,600
Speaker 1: Got it? Got it?

206
00:09:55,120 --> 00:10:00,000
Speaker 2: Okay? Connections Here, Bruce is asking actually a deep question

207
00:10:00,320 --> 00:10:02,320
Speaker 2: about the nature of the universe. He wants to know

208
00:10:02,400 --> 00:10:07,000
Speaker 2: basically what happened before the earliest time that we can understand.

209
00:10:07,440 --> 00:10:10,040
Speaker 1: Yeah, And I think he's specifically asking whether, like, what's

210
00:10:10,080 --> 00:10:14,600
Speaker 1: the connection between string theory and the origin of the universe. Like,

211
00:10:15,440 --> 00:10:17,640
Speaker 1: we know about the Big Bang, and there's a theory

212
00:10:17,640 --> 00:10:21,320
Speaker 1: called string theory. How does string theory a factor into

213
00:10:21,320 --> 00:10:23,000
Speaker 1: the Big Bang? Or what does it say about the

214
00:10:23,000 --> 00:10:23,520
Speaker 1: Big Bang?

215
00:10:23,920 --> 00:10:27,080
Speaker 2: Yeah, string theory, like all theories of quantum gravity, basically

216
00:10:27,080 --> 00:10:29,920
Speaker 2: pick up where the Big Bang leaves off. And there's

217
00:10:29,960 --> 00:10:32,680
Speaker 2: a common misconception about the Big Bang. People think of

218
00:10:32,720 --> 00:10:35,680
Speaker 2: the Big Bang as the universe starting from a single

219
00:10:35,720 --> 00:10:39,160
Speaker 2: point and all that stuff then exploding out through space.

220
00:10:39,720 --> 00:10:42,240
Speaker 2: But modern conception of the Big Bang doesn't talk about

221
00:10:42,280 --> 00:10:45,360
Speaker 2: the actual very beginning of the universe. It says the

222
00:10:45,480 --> 00:10:47,960
Speaker 2: universe right now is kind of cold and old, it's

223
00:10:48,080 --> 00:10:51,200
Speaker 2: very dilute, but we know it's expanding. And so if

224
00:10:51,240 --> 00:10:55,400
Speaker 2: you wind the clock backwards, what happens if you unexpand

225
00:10:55,520 --> 00:10:59,800
Speaker 2: The universe gets denser, things closer together. It also gets hotter,

226
00:11:00,240 --> 00:11:02,520
Speaker 2: and at some point it gets so hot and so

227
00:11:02,679 --> 00:11:05,959
Speaker 2: dense that our current theories we don't think they'll work anymore.

228
00:11:06,640 --> 00:11:09,760
Speaker 2: Because we have theories of general relativity that describes gravity

229
00:11:09,800 --> 00:11:11,800
Speaker 2: and space and time, and we have theories of quantum

230
00:11:11,800 --> 00:11:15,120
Speaker 2: mechanics that describes particles and all that fuzziness and uncertainty.

231
00:11:15,520 --> 00:11:17,920
Speaker 2: And at some point, when the universe gets dense enough,

232
00:11:18,280 --> 00:11:21,000
Speaker 2: then both of those theories come into play, and we

233
00:11:21,040 --> 00:11:22,960
Speaker 2: don't know how to fit those together. For that, we

234
00:11:23,000 --> 00:11:26,000
Speaker 2: need a theory of quantum gravity. So the Big Bang

235
00:11:26,040 --> 00:11:28,520
Speaker 2: takes us back to some very hot, dense state that's

236
00:11:28,559 --> 00:11:31,360
Speaker 2: like the limit of our understanding, but doesn't actually say

237
00:11:31,400 --> 00:11:34,520
Speaker 2: what came before that. Quantum gravity tries to explain what

238
00:11:34,559 --> 00:11:36,679
Speaker 2: happens when things get that hot and dense, and so

239
00:11:36,720 --> 00:11:38,960
Speaker 2: it might give you some insight as to what came

240
00:11:39,000 --> 00:11:41,520
Speaker 2: before the moment that we can describe up to the

241
00:11:41,520 --> 00:11:42,040
Speaker 2: Big Bang.

242
00:11:42,840 --> 00:11:45,040
Speaker 1: I wonder if there's a sort of like a distinction

243
00:11:45,120 --> 00:11:48,400
Speaker 1: you can make between these theories, like is string theory

244
00:11:48,600 --> 00:11:52,080
Speaker 1: or maybe just generally quantum theory a theory of matter,

245
00:11:53,000 --> 00:11:55,480
Speaker 1: and maybe general relativity is more of a theory about

246
00:11:55,480 --> 00:11:56,400
Speaker 1: space and time.

247
00:11:56,760 --> 00:11:59,319
Speaker 2: General relativity is definitely about space and time, but it's

248
00:11:59,320 --> 00:12:01,840
Speaker 2: also about matter and energy because it's about how all

249
00:12:01,960 --> 00:12:05,600
Speaker 2: those things interact with each other. String theory is really

250
00:12:05,600 --> 00:12:09,480
Speaker 2: a unified theory because it involves gravity. It also involves

251
00:12:09,480 --> 00:12:13,400
Speaker 2: the other forces, like quantum mechanics can describe electromagnetism and

252
00:12:13,400 --> 00:12:15,840
Speaker 2: the weak force and the strong force in terms of

253
00:12:15,920 --> 00:12:19,760
Speaker 2: quantum mechanical objects, these quantum fields and ripples passing through them.

254
00:12:20,200 --> 00:12:23,080
Speaker 2: General relativity can't explain any of that stuff, but string

255
00:12:23,160 --> 00:12:27,200
Speaker 2: theory can reproduce general relativity and the quantum theory. So

256
00:12:27,200 --> 00:12:29,400
Speaker 2: it really is a union of these two things. It

257
00:12:29,440 --> 00:12:30,800
Speaker 2: explains all of it together.

258
00:12:31,160 --> 00:12:34,720
Speaker 1: So string theory has things like this, the bending of

259
00:12:34,760 --> 00:12:37,320
Speaker 1: space and the slowing down of time, all that is

260
00:12:37,720 --> 00:12:39,840
Speaker 1: baked into the theory or did it just sort of

261
00:12:39,880 --> 00:12:42,160
Speaker 1: like absorb general relativity.

262
00:12:42,440 --> 00:12:44,960
Speaker 2: Yeah, that's a great question. One issue with string theory

263
00:12:45,280 --> 00:12:47,840
Speaker 2: is that there's a lot of string theories. Like if

264
00:12:47,880 --> 00:12:50,280
Speaker 2: you start putting these things together and saying, look, the

265
00:12:50,360 --> 00:12:53,240
Speaker 2: universe is made out of these tiny vibrating strings that

266
00:12:53,320 --> 00:12:56,600
Speaker 2: vibrate in many dimensions more than the ones that we see,

267
00:12:57,000 --> 00:12:59,520
Speaker 2: you get lots of different possible ways for those string

268
00:12:59,520 --> 00:13:02,200
Speaker 2: theories to build a universe. And we know that some

269
00:13:02,240 --> 00:13:04,640
Speaker 2: of those correspond to the universe that we live in.

270
00:13:04,880 --> 00:13:06,800
Speaker 2: We don't know how many of them and why this one.

271
00:13:07,080 --> 00:13:09,000
Speaker 2: There's a whole big question there about like why there

272
00:13:09,040 --> 00:13:12,439
Speaker 2: are so many string theories, but it is possible in

273
00:13:12,480 --> 00:13:16,080
Speaker 2: some versions of string theory to reproduce general relativity and

274
00:13:16,200 --> 00:13:18,920
Speaker 2: quantum mechanics, and so that lets you go back further

275
00:13:19,040 --> 00:13:21,559
Speaker 2: in time than our current theories, back to where the

276
00:13:21,640 --> 00:13:23,880
Speaker 2: universe was so hot and so dense that you need

277
00:13:23,920 --> 00:13:25,360
Speaker 2: that theory of quantum gravity.

278
00:13:26,200 --> 00:13:31,600
Speaker 1: So string theory does gerald relativity and quantum theory, but

279
00:13:31,840 --> 00:13:34,760
Speaker 1: it's sort of not proven, right. It's just a sort

280
00:13:34,800 --> 00:13:37,280
Speaker 1: of a theory, but it hasn't been confirmed yet.

281
00:13:37,440 --> 00:13:41,160
Speaker 2: It has definitely not been confirmed. It only describes things

282
00:13:41,160 --> 00:13:44,000
Speaker 2: that we cannot yet test. We can't create those conditions

283
00:13:44,080 --> 00:13:47,839
Speaker 2: higher than the plank temperature essentially in order to test

284
00:13:47,920 --> 00:13:50,920
Speaker 2: quantum gravity. Really yet, we had a whole episode about

285
00:13:50,960 --> 00:13:53,960
Speaker 2: whether you could test quantum gravity with like tabletop experiments.

286
00:13:54,160 --> 00:13:57,120
Speaker 2: There's some clever ideas there, but currently string theory is

287
00:13:57,200 --> 00:13:59,640
Speaker 2: just a theory of quantum gravity. It's still got some

288
00:13:59,640 --> 00:14:03,440
Speaker 2: mathema medical issues. Also, we can't describe like dark energy

289
00:14:03,520 --> 00:14:06,120
Speaker 2: and the expansion very well. But it does give you

290
00:14:06,160 --> 00:14:08,959
Speaker 2: a cool picture of how the universe might work if

291
00:14:08,960 --> 00:14:09,600
Speaker 2: it's correct.

292
00:14:10,559 --> 00:14:12,840
Speaker 1: Well, okay, so then it can do both things. Then

293
00:14:12,880 --> 00:14:14,600
Speaker 1: what does it say about the Big Bang.

294
00:14:14,720 --> 00:14:17,880
Speaker 2: It says something pretty cool. Actually, it tells you that

295
00:14:17,920 --> 00:14:21,000
Speaker 2: the universe can't compress beyond a certain point, like there's

296
00:14:21,000 --> 00:14:24,640
Speaker 2: a minimum size to these strings. General relativity has no

297
00:14:24,680 --> 00:14:27,920
Speaker 2: problem compressing the universe infinitely until every part of space

298
00:14:28,120 --> 00:14:31,320
Speaker 2: is infinitely dense. But when you fold the quantum nature

299
00:14:31,360 --> 00:14:33,560
Speaker 2: of these strings in, it says, look, everything in the

300
00:14:33,600 --> 00:14:35,520
Speaker 2: universe has made it these vibrating strings, and they have

301
00:14:35,640 --> 00:14:38,920
Speaker 2: like a minimum size. That tells you the universe could

302
00:14:38,920 --> 00:14:41,640
Speaker 2: never have gotten denser than a certain level.

303
00:14:41,680 --> 00:14:43,320
Speaker 1: Wait, is that what it says? Or does it say

304
00:14:43,320 --> 00:14:45,720
Speaker 1: that you can't have things that are smaller than that?

305
00:14:45,760 --> 00:14:47,680
Speaker 1: But could the universe be smaller than the things it

306
00:14:47,760 --> 00:14:48,040
Speaker 1: can have?

307
00:14:48,360 --> 00:14:52,000
Speaker 2: Ooh wow, that's a debilosophical question. So first of all,

308
00:14:52,000 --> 00:14:53,640
Speaker 2: we're not talking about the size of the universe. We're

309
00:14:53,640 --> 00:14:56,240
Speaker 2: talking about density, right, We're talking about the whole universe,

310
00:14:56,240 --> 00:14:58,640
Speaker 2: which could be infinite anyway, and could have always been

311
00:14:58,680 --> 00:15:01,600
Speaker 2: infinite and could always be infinite. We talked about changing

312
00:15:01,640 --> 00:15:04,840
Speaker 2: from high density in the early universe to low density now,

313
00:15:05,200 --> 00:15:08,000
Speaker 2: so it's really more of a density than size. But

314
00:15:08,240 --> 00:15:10,400
Speaker 2: on your question, I do think the universe has to

315
00:15:10,400 --> 00:15:12,240
Speaker 2: be at least as big as the stuff in it?

316
00:15:12,520 --> 00:15:15,240
Speaker 1: Why can it be compressed more than the things that

317
00:15:15,280 --> 00:15:17,360
Speaker 1: it can have in it? Like, for example, my car

318
00:15:17,400 --> 00:15:20,760
Speaker 1: can be compressed smaller than what I can fit in it.

319
00:15:23,520 --> 00:15:25,840
Speaker 2: In order something to be in the universe, it has

320
00:15:25,920 --> 00:15:28,760
Speaker 2: to have a location in the universe, which means the

321
00:15:28,840 --> 00:15:30,720
Speaker 2: distance from one side of it to the other side

322
00:15:30,720 --> 00:15:33,880
Speaker 2: of it has to exist, so that space exists, and

323
00:15:33,920 --> 00:15:37,440
Speaker 2: so that's part of the universe. So therefore, the universe

324
00:15:37,480 --> 00:15:39,120
Speaker 2: has to be at least as big as the stuff

325
00:15:39,120 --> 00:15:39,400
Speaker 2: in it.

326
00:15:40,000 --> 00:15:42,760
Speaker 1: Why can't it be smaller or more dense? Just like

327
00:15:42,800 --> 00:15:44,240
Speaker 1: why can't my car be smaller than me?

328
00:15:44,520 --> 00:15:46,400
Speaker 2: Well, if your car was smaller than you, you couldn't

329
00:15:46,400 --> 00:15:46,800
Speaker 2: get in it.

330
00:15:46,880 --> 00:15:49,200
Speaker 1: Yeah, but it'd still be a car. Like I could

331
00:15:49,240 --> 00:15:51,080
Speaker 1: take my car and scrunch it down to the size

332
00:15:51,120 --> 00:15:54,440
Speaker 1: of a basketball, still be my car. I just couldn't

333
00:15:54,440 --> 00:15:56,280
Speaker 1: fit in it. But it doesn't mean that it's not

334
00:15:56,360 --> 00:15:56,680
Speaker 1: my car.

335
00:15:56,960 --> 00:15:59,880
Speaker 2: That's true. But the universe contains everything that's in the universe.

336
00:16:00,160 --> 00:16:02,120
Speaker 2: So if you're in the universe, the universe is at

337
00:16:02,160 --> 00:16:04,080
Speaker 2: least as big as you are. Even if your car

338
00:16:04,120 --> 00:16:06,520
Speaker 2: has shrunk smaller than you are, right.

339
00:16:06,440 --> 00:16:08,000
Speaker 1: Well, it could still have me in it, I would

340
00:16:08,080 --> 00:16:09,440
Speaker 1: just be squeesced through a bulb.

341
00:16:11,240 --> 00:16:13,840
Speaker 2: I see. Well, the thing about quantum strings is they

342
00:16:13,840 --> 00:16:15,880
Speaker 2: think that there really is a minimum size there, like

343
00:16:15,880 --> 00:16:19,920
Speaker 2: a quantum mechanical minimum beyond which you cannot shrink them.

344
00:16:20,280 --> 00:16:22,960
Speaker 2: If you add another feature of quantum mechanics, which is

345
00:16:23,040 --> 00:16:26,120
Speaker 2: time reversibility, then all the laws of physics seem to

346
00:16:26,120 --> 00:16:29,520
Speaker 2: go equally well backwards and forwards in time. It naturally

347
00:16:29,520 --> 00:16:33,280
Speaker 2: brings you to a bounce scenario where the universe infinitely

348
00:16:33,320 --> 00:16:36,960
Speaker 2: far back in time may have been infinitely dilute, and

349
00:16:37,000 --> 00:16:41,680
Speaker 2: then it gradually gathered together towards a hotter, denser state,

350
00:16:41,760 --> 00:16:44,800
Speaker 2: and then when it reached the maximum density, it basically

351
00:16:44,880 --> 00:16:48,880
Speaker 2: bounced back, expanding out again, and then then expanding out

352
00:16:48,920 --> 00:16:50,400
Speaker 2: again and creating our universe.

353
00:16:50,480 --> 00:16:52,080
Speaker 1: They called that the big bounce, Right.

354
00:16:52,040 --> 00:16:54,320
Speaker 2: Yeah, that's like the big bounce. The big bounce comes

355
00:16:54,320 --> 00:16:57,680
Speaker 2: in lots of different varieties, but some versions of string

356
00:16:57,760 --> 00:17:01,080
Speaker 2: theory are very nicely compatible with this kind of big bounce,

357
00:17:01,080 --> 00:17:03,480
Speaker 2: and it gives you a reason for the bounce. Right,

358
00:17:03,680 --> 00:17:06,800
Speaker 2: Why didn't the universe just keep compressing until infinite density

359
00:17:06,800 --> 00:17:08,959
Speaker 2: and go on and on and on the answer is,

360
00:17:09,080 --> 00:17:12,480
Speaker 2: strings pushed back strings of a minimum length, which means

361
00:17:12,520 --> 00:17:16,320
Speaker 2: a maximum density, and that is where the bounce comes from.

362
00:17:15,760 --> 00:17:18,760
Speaker 1: M Does that mean that the era of time continues

363
00:17:18,840 --> 00:17:19,840
Speaker 1: beyond the Big Bang?

364
00:17:20,040 --> 00:17:22,160
Speaker 2: Yeah, it means that that earliest moment that we can

365
00:17:22,160 --> 00:17:25,160
Speaker 2: describe with our current theories, that's what we typically describe

366
00:17:25,160 --> 00:17:27,800
Speaker 2: as the Big Bang. We could extrapolate back further to

367
00:17:27,920 --> 00:17:31,040
Speaker 2: some higher density but not infinite density, and then even

368
00:17:31,080 --> 00:17:32,960
Speaker 2: back through that to when the universe is doing the

369
00:17:33,040 --> 00:17:34,200
Speaker 2: inverse Big Bang.

370
00:17:34,520 --> 00:17:37,600
Speaker 1: WHOA, And was that universe kind of like a mirror

371
00:17:37,640 --> 00:17:40,679
Speaker 1: imagere of our universe just running backwards in time or

372
00:17:40,760 --> 00:17:42,320
Speaker 1: is it a totally different universe?

373
00:17:42,600 --> 00:17:44,680
Speaker 2: We think you should have the same laws of physics

374
00:17:44,680 --> 00:17:47,040
Speaker 2: because it's built out of the same basic strings. But yes,

375
00:17:47,040 --> 00:17:48,920
Speaker 2: it's running backwards through time if you're thinking about it

376
00:17:48,960 --> 00:17:51,160
Speaker 2: in that direction. Really, the way to think about it

377
00:17:51,200 --> 00:17:54,520
Speaker 2: is to start deep in the infinite past, running forwards

378
00:17:54,520 --> 00:17:56,879
Speaker 2: in time as that universe is compressing. So that'd be

379
00:17:56,920 --> 00:17:59,480
Speaker 2: a very different universe to live in, because that universe

380
00:17:59,520 --> 00:18:01,359
Speaker 2: wouldn't be expanding like ours is.

381
00:18:01,640 --> 00:18:04,080
Speaker 1: It would be shrinking, And would it have the same

382
00:18:04,119 --> 00:18:07,000
Speaker 1: things like dark energy, which is in our side of

383
00:18:07,040 --> 00:18:10,159
Speaker 1: the universe mirror expanding the universe, wouldn't it also have

384
00:18:10,400 --> 00:18:11,679
Speaker 1: dark energy expanding it?

385
00:18:11,800 --> 00:18:14,760
Speaker 2: Well, string theory can't always accommodate or explain dark energy,

386
00:18:14,800 --> 00:18:16,480
Speaker 2: so that part is still a bit of a question

387
00:18:16,600 --> 00:18:19,640
Speaker 2: mark where that comes from, where that's shrinking, and then

388
00:18:19,680 --> 00:18:23,159
Speaker 2: expansion comes from originally, So that's still something to be

389
00:18:23,200 --> 00:18:25,679
Speaker 2: figured out. As you can tell, this is all a

390
00:18:25,680 --> 00:18:28,400
Speaker 2: little bit sketchy because string theory itself has so many

391
00:18:28,480 --> 00:18:31,320
Speaker 2: varieties that there's like a thousand different directions people are

392
00:18:31,359 --> 00:18:33,439
Speaker 2: exploring it in, and so if you read up on

393
00:18:33,480 --> 00:18:36,240
Speaker 2: like string cosmology, you'll see this scenario, but also like

394
00:18:36,400 --> 00:18:39,320
Speaker 2: five hundred other ideas for how strings could explain the

395
00:18:39,320 --> 00:18:40,680
Speaker 2: Big Bang or what came before it?

396
00:18:40,720 --> 00:18:43,160
Speaker 1: Did you just call it extreme cosmology?

397
00:18:44,359 --> 00:18:45,560
Speaker 2: String cosmology?

398
00:18:45,840 --> 00:18:47,360
Speaker 1: String or extreme?

399
00:18:48,480 --> 00:18:49,760
Speaker 2: Yeah? It is pretty extreme.

400
00:18:49,840 --> 00:18:55,560
Speaker 1: Also they both sounds pretty exciting. Oh, I say it's

401
00:18:55,560 --> 00:18:58,920
Speaker 1: string cosmology, not extreme chrismology exactly.

402
00:18:59,200 --> 00:19:01,600
Speaker 2: But you know, Bruce is wondering, is it possible for

403
00:19:01,680 --> 00:19:04,320
Speaker 2: those strings in the very early universe to decay down

404
00:19:04,320 --> 00:19:07,679
Speaker 2: and create our particles? And the answer is yes, absolutely.

405
00:19:08,000 --> 00:19:10,359
Speaker 2: If string theories right, then the universe was much denser

406
00:19:10,359 --> 00:19:13,240
Speaker 2: than even our quantum field theory of particles can describe

407
00:19:13,359 --> 00:19:17,000
Speaker 2: a moment when everything was these crazy bouncing strings.

408
00:19:17,440 --> 00:19:20,639
Speaker 1: And then those strings became quantum particles, and then those

409
00:19:20,720 --> 00:19:24,000
Speaker 1: quantum particles became us, and then someone became boba balls

410
00:19:24,080 --> 00:19:30,199
Speaker 1: which try to kill Daniel apparently unsuccessfully. Unsuccessfully so far,

411
00:19:30,720 --> 00:19:34,879
Speaker 1: so far. They'll get you yet, Daniel, They'll sneak up

412
00:19:34,880 --> 00:19:35,119
Speaker 1: on you.

413
00:19:35,480 --> 00:19:38,520
Speaker 2: That's a horror movie right there, a man being followed

414
00:19:38,520 --> 00:19:40,480
Speaker 2: by bubba.

415
00:19:42,720 --> 00:19:46,199
Speaker 1: That would be scary for like three people, yeah, including you,

416
00:19:46,280 --> 00:19:46,840
Speaker 1: I guess.

417
00:19:47,240 --> 00:19:49,000
Speaker 2: But it is possible that we could one day know

418
00:19:49,119 --> 00:19:52,600
Speaker 2: more than just speculate, because these theories do make some

419
00:19:52,640 --> 00:19:55,919
Speaker 2: predictions the very early universe. It's expansion and all the

420
00:19:56,000 --> 00:20:02,080
Speaker 2: dynamics are predicted to leave gravitational way bouncing around the universe.

421
00:20:02,119 --> 00:20:05,600
Speaker 2: These are called primordial gravitational waves. If those are there

422
00:20:05,640 --> 00:20:06,919
Speaker 2: and we can pick them up and measure them, we

423
00:20:06,960 --> 00:20:10,320
Speaker 2: could learn something. But what happened in that early state

424
00:20:10,440 --> 00:20:14,080
Speaker 2: before quantum field theory can describe basically before the Big Bang?

425
00:20:14,320 --> 00:20:17,199
Speaker 1: Well, so I guess in this version gravitational waves are

426
00:20:17,240 --> 00:20:18,359
Speaker 1: not made out of particles.

427
00:20:18,400 --> 00:20:22,800
Speaker 2: Then, no, they're not boba particles or anything. They're real

428
00:20:22,920 --> 00:20:25,800
Speaker 2: ripples in space time. But these would be very very subtle.

429
00:20:26,040 --> 00:20:27,920
Speaker 2: There was an experiment a few years ago they claim

430
00:20:28,000 --> 00:20:30,880
Speaker 2: to have measured primordial gravitational waves, but it turns out

431
00:20:31,040 --> 00:20:34,359
Speaker 2: they were just measuring dust. It's a hard problem.

432
00:20:34,400 --> 00:20:36,760
Speaker 1: All right. Well that's the answer for Bruce. What a

433
00:20:36,800 --> 00:20:39,840
Speaker 1: string theory say about the Big Bang? It says that

434
00:20:40,600 --> 00:20:43,280
Speaker 1: maybe the Big Bang just came from the big bounce

435
00:20:43,640 --> 00:20:47,040
Speaker 1: mm hmm, and that from that came quantum particles in

436
00:20:47,320 --> 00:20:51,439
Speaker 1: quantum things, including quantum theories, extreme theories of the use.

437
00:20:51,600 --> 00:20:56,240
Speaker 1: That's right, extreme and string both alike. All Right, thanks

438
00:20:56,240 --> 00:20:58,840
Speaker 1: Bruce for that question. Let's get to our second question.

439
00:20:59,080 --> 00:21:04,159
Speaker 1: This one is about cosmic strings, which has nothing to

440
00:21:04,200 --> 00:21:10,240
Speaker 1: do with string chrismology at all, like at all. It's

441
00:21:10,280 --> 00:21:13,080
Speaker 1: a totally different thing, super interesting. So let's get to

442
00:21:13,119 --> 00:21:28,159
Speaker 1: that question. But first let's take a quick break. Right.

443
00:21:28,200 --> 00:21:31,160
Speaker 1: We're answering listener questions here today, and our second question

444
00:21:31,680 --> 00:21:36,800
Speaker 1: is pretty cosmic, dude. It's about cosmic strings, and it

445
00:21:36,840 --> 00:21:38,120
Speaker 1: comes from Dane.

446
00:21:38,359 --> 00:21:41,960
Speaker 5: Hy Daniel and Jorge in articles about the newly discovered

447
00:21:41,960 --> 00:21:45,560
Speaker 5: big ring megastructure. I've seen cosmic strings mentioned several times

448
00:21:45,560 --> 00:21:49,280
Speaker 5: as a possible cause if cosmic strings even exist, what

449
00:21:49,400 --> 00:21:52,879
Speaker 5: happens when one intersects a black hole. Also, what happens

450
00:21:52,920 --> 00:21:56,240
Speaker 5: when normal matter contacts a cosmic string? Is it pulled

451
00:21:56,240 --> 00:21:59,800
Speaker 5: into the string? Is a cosmic string effectively a black line?

452
00:22:00,359 --> 00:22:02,840
Speaker 5: Also is there a stable orbital path around a string?

453
00:22:03,119 --> 00:22:05,719
Speaker 5: If so, what would that be? A ring, a spiral,

454
00:22:05,800 --> 00:22:10,080
Speaker 5: or corkscrew something else. Thanks for any clarification you can provide.

455
00:22:10,200 --> 00:22:13,040
Speaker 5: I think cosmic strings are really weird.

456
00:22:12,520 --> 00:22:16,240
Speaker 1: All right, an interesting question here, and again, cosmic strings

457
00:22:16,280 --> 00:22:18,320
Speaker 1: have nothing to do with string theory.

458
00:22:18,760 --> 00:22:21,360
Speaker 2: Yeah, it's almost as if the names and physics are

459
00:22:21,400 --> 00:22:22,840
Speaker 2: just not very well thought out.

460
00:22:23,320 --> 00:22:26,120
Speaker 1: A little bit. I mean I've sort of been saying

461
00:22:26,160 --> 00:22:28,600
Speaker 1: that for five years.

462
00:22:29,440 --> 00:22:31,760
Speaker 2: Yeah, I think you put it very well. Cosmic strings

463
00:22:31,800 --> 00:22:36,239
Speaker 2: have nothing to do with string cosmology. Totally separate questions.

464
00:22:35,760 --> 00:22:39,359
Speaker 1: But they could be related, right, Like, for example, string

465
00:22:39,400 --> 00:22:40,959
Speaker 1: theory could account for cosmic strings.

466
00:22:40,960 --> 00:22:43,480
Speaker 2: For example, if string theory is correct, then it accounts

467
00:22:43,480 --> 00:22:46,560
Speaker 2: for everything. So then yes, cosmic strings are made out

468
00:22:46,560 --> 00:22:47,920
Speaker 2: of tiny quantum strings.

469
00:22:48,000 --> 00:22:49,760
Speaker 1: Okay, it's like a string made out of strings.

470
00:22:49,880 --> 00:22:52,240
Speaker 2: Yeah, exactly. Like if string theory is right, then the

471
00:22:52,280 --> 00:22:54,000
Speaker 2: yard that made your sweater is also made out of

472
00:22:54,040 --> 00:22:56,800
Speaker 2: quantum strings, so you're wearing like a string.

473
00:22:56,840 --> 00:23:00,119
Speaker 1: Theory sweater right, right, but we don't know. I guess yes,

474
00:23:00,600 --> 00:23:03,679
Speaker 1: there hasn't been that connection yet. But cosmic strings is

475
00:23:03,680 --> 00:23:05,960
Speaker 1: something that comes out of just general relativity.

476
00:23:06,040 --> 00:23:08,520
Speaker 2: Right, Cosmic strings is an idea that does come out

477
00:23:08,520 --> 00:23:12,080
Speaker 2: of general relativity, but it's also related to quantum mechanics.

478
00:23:12,119 --> 00:23:14,639
Speaker 2: It has to do with how the universe is cooling

479
00:23:15,040 --> 00:23:16,840
Speaker 2: and how the laws of physics and the sort of

480
00:23:16,880 --> 00:23:21,760
Speaker 2: state of space itself changes and cracks as the universe cools.

481
00:23:22,119 --> 00:23:25,040
Speaker 1: Well, all right, well maybe break it down for us.

482
00:23:25,040 --> 00:23:26,080
Speaker 1: What is a cosmic string?

483
00:23:26,200 --> 00:23:29,400
Speaker 2: So cosmic string is like a topological defect in space.

484
00:23:29,800 --> 00:23:32,760
Speaker 1: It's a theoretical concept first of all, right, like nobody's

485
00:23:32,800 --> 00:23:35,720
Speaker 1: sen one. It's just something people think might exist out there.

486
00:23:35,920 --> 00:23:38,080
Speaker 2: Yeah, it's just an idea so far. It would be

487
00:23:38,160 --> 00:23:41,359
Speaker 2: interesting because they're like a boundary. They're like a spot

488
00:23:41,400 --> 00:23:44,960
Speaker 2: where space behaves differently, not like the laws of physics

489
00:23:45,000 --> 00:23:47,760
Speaker 2: themselves are different, but it's like space is in a

490
00:23:47,760 --> 00:23:50,240
Speaker 2: different phase. If you think about the universe from the

491
00:23:50,359 --> 00:23:53,439
Speaker 2: very initial days, things are hot and dense. You can

492
00:23:53,520 --> 00:23:55,600
Speaker 2: use a sort of certain set of laws to describe it,

493
00:23:55,720 --> 00:23:57,720
Speaker 2: the same way that you use like the ideal gas

494
00:23:57,800 --> 00:24:00,480
Speaker 2: law to describe water when it's a gas, and you

495
00:24:00,560 --> 00:24:02,879
Speaker 2: use fluid dynamics to describe it when it's a fluid,

496
00:24:03,119 --> 00:24:05,800
Speaker 2: and use like crystal theory describe it when it's a lattice.

497
00:24:06,000 --> 00:24:08,879
Speaker 2: Things are a different temperature, you have different effective laws

498
00:24:08,880 --> 00:24:11,600
Speaker 2: that describe them. We think the universe is the same way.

499
00:24:11,680 --> 00:24:14,720
Speaker 2: And as the universe cools, as things expand and get

500
00:24:14,760 --> 00:24:18,000
Speaker 2: more dilute, different effective laws take over. And so the

501
00:24:18,080 --> 00:24:19,760
Speaker 2: universe sort of has different phases.

502
00:24:20,080 --> 00:24:24,200
Speaker 1: Phases with a pH right like phase like solid or liquid.

503
00:24:24,440 --> 00:24:27,199
Speaker 2: Yeah, phases, not faces. I don't know if there are

504
00:24:27,200 --> 00:24:29,680
Speaker 2: any faces in the universe except for the one on Mars.

505
00:24:30,000 --> 00:24:32,600
Speaker 2: But yeah, we think about phases more generally than just

506
00:24:32,640 --> 00:24:35,320
Speaker 2: like the phases of matter. Businists think about them as

507
00:24:35,359 --> 00:24:38,120
Speaker 2: like regions where your laws of physics are applicable, because

508
00:24:38,119 --> 00:24:40,960
Speaker 2: there's always boundaries to where your laws work. Just like

509
00:24:41,000 --> 00:24:43,160
Speaker 2: we were talking about how quantum field theory works up

510
00:24:43,160 --> 00:24:46,160
Speaker 2: to a certain temperature and beyond that it doesn't work anymore.

511
00:24:46,440 --> 00:24:48,359
Speaker 2: So there's a phase in which you can talk about

512
00:24:48,600 --> 00:24:50,880
Speaker 2: quantum fields, and beyond that it's sort of nonsense.

513
00:24:51,040 --> 00:24:52,879
Speaker 1: And so it is that after the Big Bang, everything

514
00:24:52,960 --> 00:24:55,919
Speaker 1: was super hot and things kind of settle down, and like,

515
00:24:56,000 --> 00:24:59,600
Speaker 1: for example, around us, the universe settle into a particular phase,

516
00:25:00,080 --> 00:25:04,440
Speaker 1: particular set of laws or arrangement of the quantum fields.

517
00:25:05,000 --> 00:25:07,399
Speaker 1: But maybe next door to us, a few thousand or

518
00:25:07,520 --> 00:25:10,679
Speaker 1: bazillion light years away, maybe it started settling in a

519
00:25:10,760 --> 00:25:12,840
Speaker 1: totally different set of laws or phase.

520
00:25:13,240 --> 00:25:15,760
Speaker 2: Because as the universe cools, there's a few different ways

521
00:25:15,760 --> 00:25:18,560
Speaker 2: that it could cool down. It's like a ball rolling

522
00:25:18,600 --> 00:25:20,959
Speaker 2: down a hill, but that hill has interesting features in it,

523
00:25:21,200 --> 00:25:23,120
Speaker 2: so maybe it gets stuck on a shelf, or maybe

524
00:25:23,119 --> 00:25:24,520
Speaker 2: it goes all the way down to the valley.

525
00:25:24,680 --> 00:25:26,639
Speaker 1: And is there an infinite number of bases of the

526
00:25:26,720 --> 00:25:29,040
Speaker 1: universe that the universe can be or is there a

527
00:25:29,320 --> 00:25:30,280
Speaker 1: like three or four.

528
00:25:30,200 --> 00:25:32,119
Speaker 2: Well, we don't really know. It depends on the nature

529
00:25:32,160 --> 00:25:34,760
Speaker 2: of all those quantum fields. For example, we know that

530
00:25:34,800 --> 00:25:37,600
Speaker 2: in our portion of the universe we have not settled

531
00:25:37,600 --> 00:25:40,480
Speaker 2: into like the lowest energy possible state of the universe.

532
00:25:40,560 --> 00:25:43,119
Speaker 2: Some of the fields that fill space got stuck, like

533
00:25:43,160 --> 00:25:45,040
Speaker 2: the Higgs field. The Higgs field has a lot of

534
00:25:45,200 --> 00:25:47,720
Speaker 2: energy in it, and that's why we have mass. And

535
00:25:48,119 --> 00:25:49,879
Speaker 2: when things interact with the Higgs field, there's a lot

536
00:25:49,880 --> 00:25:53,159
Speaker 2: of energy stored in that field, it hasn't fully relaxed,

537
00:25:53,200 --> 00:25:56,000
Speaker 2: and we talked about how if it did spontaneously collapse,

538
00:25:56,040 --> 00:25:58,400
Speaker 2: that would change the nature of physics. It would lead

539
00:25:58,440 --> 00:26:02,199
Speaker 2: to a new phase of the universe in which the

540
00:26:02,359 --> 00:26:05,040
Speaker 2: same fundamental laws might apply. But you know, everything we've

541
00:26:05,119 --> 00:26:08,320
Speaker 2: learned about atomic physics and chemistry and whatever wouldn't apply.

542
00:26:08,960 --> 00:26:10,960
Speaker 2: So in our region of the universe we're in a

543
00:26:10,960 --> 00:26:14,080
Speaker 2: certain phase, like space is cooled in a certain way.

544
00:26:14,720 --> 00:26:16,800
Speaker 2: Are there different options? We don't really know, because we

545
00:26:16,800 --> 00:26:19,720
Speaker 2: don't fully understand the nature of the Higgs field and

546
00:26:19,760 --> 00:26:21,919
Speaker 2: the other fields that might be out there once for

547
00:26:22,040 --> 00:26:24,960
Speaker 2: dark matter or dark energy. There's lots of potential fields

548
00:26:24,960 --> 00:26:26,480
Speaker 2: out there in the universe.

549
00:26:27,000 --> 00:26:29,080
Speaker 1: So there might be part of the universe out there

550
00:26:29,160 --> 00:26:32,280
Speaker 1: beyond the observable universe, right, because as far as we know,

551
00:26:32,359 --> 00:26:36,000
Speaker 1: the observable universe is the same phase. Right, I imagine,

552
00:26:36,359 --> 00:26:37,000
Speaker 1: as far as.

553
00:26:36,840 --> 00:26:38,560
Speaker 2: We can tell, the same laws of physics to apply

554
00:26:38,600 --> 00:26:42,040
Speaker 2: everywhere in the observable universe. So yeah, most likely these

555
00:26:42,040 --> 00:26:44,240
Speaker 2: things would exist past the observable universe.

556
00:26:44,320 --> 00:26:46,600
Speaker 1: Then the idea is that maybe beyond the observable universe,

557
00:26:46,640 --> 00:26:50,919
Speaker 1: there's in the same universe, there's another phase expanding or

558
00:26:50,960 --> 00:26:53,320
Speaker 1: growing or settling, just like we are, and at some

559
00:26:53,320 --> 00:26:55,920
Speaker 1: point they have to meet. And if they meet, is

560
00:26:56,240 --> 00:26:59,159
Speaker 1: it like a big disaster or can both types of

561
00:26:59,280 --> 00:27:01,520
Speaker 1: universes coexists next to each other?

562
00:27:01,680 --> 00:27:04,800
Speaker 2: Well, the theory of cosmic strings is that they can coexist,

563
00:27:04,880 --> 00:27:06,800
Speaker 2: and then you get this weird boundary, and that's the

564
00:27:06,880 --> 00:27:10,560
Speaker 2: cosmic string. It's like a crack in space where the

565
00:27:10,720 --> 00:27:13,560
Speaker 2: laws are different on one side and the other. These

566
00:27:13,560 --> 00:27:16,640
Speaker 2: can be like two dimensional, like a whole surface where

567
00:27:16,640 --> 00:27:18,360
Speaker 2: the laws are on different on one side and the other.

568
00:27:18,480 --> 00:27:20,400
Speaker 2: They could even be like one dimensional, and that's where

569
00:27:20,400 --> 00:27:23,600
Speaker 2: the idea of cosmic string comes in. These like long,

570
00:27:23,760 --> 00:27:26,560
Speaker 2: weird cracks in space, but the laws are a little

571
00:27:26,560 --> 00:27:30,680
Speaker 2: bit different just in that like one feptometer wide cosmic

572
00:27:30,800 --> 00:27:34,160
Speaker 2: string that could be like ninety billion light years long.

573
00:27:35,119 --> 00:27:38,320
Speaker 1: Well, I guess I'm thinking of like bubbles. Like if

574
00:27:38,359 --> 00:27:40,480
Speaker 1: we're in a bubble and there's a bubble next to us,

575
00:27:40,520 --> 00:27:43,320
Speaker 1: where the two bubbles meet, you get a wall basically, right,

576
00:27:43,400 --> 00:27:45,720
Speaker 1: mm hmmm. Is that what we're talking about in terms

577
00:27:45,760 --> 00:27:47,800
Speaker 1: of the interface between two phases, Like it could be

578
00:27:47,840 --> 00:27:50,760
Speaker 1: a wall, or sometimes if you get like three bubbles,

579
00:27:50,920 --> 00:27:53,960
Speaker 1: then you can sort of get a line between the

580
00:27:54,000 --> 00:27:56,119
Speaker 1: three bubbles. Is that what you mean by a string?

581
00:27:56,320 --> 00:27:58,359
Speaker 2: Yeah, here we're talking about a line, and the bubble

582
00:27:58,400 --> 00:27:59,840
Speaker 2: analogy mostly works.

583
00:28:00,040 --> 00:28:05,520
Speaker 1: Okay, let's go with boba. If it got three boba balls, it's.

584
00:28:05,440 --> 00:28:07,520
Speaker 2: My mental kryptonite. I can't even think now. I'm just

585
00:28:07,560 --> 00:28:09,000
Speaker 2: worried about choking the whole time.

586
00:28:09,520 --> 00:28:11,160
Speaker 1: Get over it, Daniel, it's the new thing.

587
00:28:11,480 --> 00:28:15,560
Speaker 2: I can't. I can't that what roughly works, the boba analogy.

588
00:28:15,960 --> 00:28:18,880
Speaker 2: But it is possible for space to crack as it's

589
00:28:18,920 --> 00:28:22,080
Speaker 2: cooling in this sort of uneven way and create these

590
00:28:22,119 --> 00:28:24,480
Speaker 2: one dimensional ripples in space.

591
00:28:24,880 --> 00:28:26,040
Speaker 1: Whoa what does that mean?

592
00:28:26,119 --> 00:28:26,199
Speaker 2: Like?

593
00:28:26,240 --> 00:28:28,639
Speaker 1: How can a string have two sides to it?

594
00:28:28,720 --> 00:28:28,840
Speaker 3: Right?

595
00:28:28,880 --> 00:28:31,920
Speaker 1: Because if you're saying it's the intersection between two universes,

596
00:28:31,960 --> 00:28:32,920
Speaker 1: like which side is what.

597
00:28:33,400 --> 00:28:35,520
Speaker 2: This scenario we have like a cosmic wall, give an

598
00:28:35,560 --> 00:28:38,640
Speaker 2: interface between two portions of three D space. But you

599
00:28:38,680 --> 00:28:40,720
Speaker 2: can also get space just cooling in this way where

600
00:28:40,760 --> 00:28:43,280
Speaker 2: you have a line that's a different phase and the

601
00:28:43,320 --> 00:28:45,800
Speaker 2: rest of space is all the same. So it's like

602
00:28:45,840 --> 00:28:49,160
Speaker 2: a tube of space that's different than the rest of it.

603
00:28:49,640 --> 00:28:51,880
Speaker 1: Oh wait, wait, wait, does a cosmic string is more

604
00:28:51,920 --> 00:28:52,960
Speaker 1: like a cosmic tube.

605
00:28:53,280 --> 00:28:55,680
Speaker 2: Yeah, because it's not really one dimensional. It's like one

606
00:28:55,760 --> 00:28:59,520
Speaker 2: femtometer wide but very very long. So it's like a

607
00:28:59,520 --> 00:29:01,880
Speaker 2: cosmic hair or something that's very very long.

608
00:29:02,120 --> 00:29:05,920
Speaker 1: Whoa, and inside of that hair is a whole different universe.

609
00:29:06,160 --> 00:29:09,840
Speaker 2: Yeah, exactly, And they think they're probably higher energy. The

610
00:29:09,960 --> 00:29:12,600
Speaker 2: universe hasn't cooled in those places as much. It's like

611
00:29:12,680 --> 00:29:15,800
Speaker 2: hotter and denser. So these things, if they exist, they

612
00:29:15,800 --> 00:29:20,640
Speaker 2: are gravitational objects because they're immensely dense. They're basically stuffed

613
00:29:20,680 --> 00:29:25,000
Speaker 2: filled with original primordial energy. Imagine like a tube of

614
00:29:25,040 --> 00:29:28,440
Speaker 2: the original hot dense universe that's never cooled. It got

615
00:29:28,480 --> 00:29:32,080
Speaker 2: like stuck at some hot dense statement's still around.

616
00:29:32,040 --> 00:29:34,640
Speaker 1: Like it somehow got trapped, right, is that the idea

617
00:29:34,720 --> 00:29:37,400
Speaker 1: like maybe like the universe started settling into our kind

618
00:29:37,400 --> 00:29:40,600
Speaker 1: of universe all around it, and as those things grew,

619
00:29:41,000 --> 00:29:43,720
Speaker 1: there's a certain amount of primordial energy you got trapped

620
00:29:43,720 --> 00:29:47,080
Speaker 1: and squeeze into uh, basically spaghetti.

621
00:29:47,360 --> 00:29:49,480
Speaker 2: Yes, exactly, cosmic pasta.

622
00:29:49,640 --> 00:29:56,520
Speaker 1: Yeah, that's a better name for it. Cosmic city or rigatoni.

623
00:29:56,840 --> 00:30:00,000
Speaker 1: I don't know. Oh no, wait, bugatoni, that's the right, right,

624
00:30:00,640 --> 00:30:01,600
Speaker 1: that would be the rest Well.

625
00:30:02,080 --> 00:30:04,600
Speaker 2: Not an expert sounds good. All right, So now I

626
00:30:04,600 --> 00:30:06,440
Speaker 2: think we're finally ready to answer Dane's question.

627
00:30:06,720 --> 00:30:09,280
Speaker 1: Oh right, right, what was this question again?

628
00:30:09,920 --> 00:30:12,480
Speaker 2: What happens when a cosmic string hits a black hole?

629
00:30:12,920 --> 00:30:13,080
Speaker 1: Oh?

630
00:30:13,080 --> 00:30:15,480
Speaker 2: Okay, he wants to throw that spaghetti against the wall.

631
00:30:15,600 --> 00:30:17,360
Speaker 1: I see he wants to throw the spaghetti against like

632
00:30:17,360 --> 00:30:17,880
Speaker 1: a meat ball.

633
00:30:21,400 --> 00:30:24,440
Speaker 2: Yeah. And the short answer is, we're not sure because

634
00:30:24,560 --> 00:30:27,800
Speaker 2: cosmic strings are features of a kind of theory of

635
00:30:27,880 --> 00:30:30,400
Speaker 2: quantum gravity, because as you hear, they're all about how

636
00:30:30,480 --> 00:30:34,080
Speaker 2: quantum fields are cooling, but they also involve space. You know,

637
00:30:34,080 --> 00:30:37,880
Speaker 2: you have energy density deformation of space, and black holes

638
00:30:37,880 --> 00:30:39,640
Speaker 2: are a feature of general relativity. They don't know how

639
00:30:39,640 --> 00:30:42,800
Speaker 2: to talk to quantum mechanics, and so we're not exactly

640
00:30:42,880 --> 00:30:44,680
Speaker 2: sure what would happen because we don't really have a

641
00:30:44,720 --> 00:30:48,440
Speaker 2: full theory of quantum gravity that would explain how quantum

642
00:30:48,440 --> 00:30:50,600
Speaker 2: fields behave near a black hole.

643
00:30:50,920 --> 00:30:53,400
Speaker 1: Well, I guess the question are they both even compatible?

644
00:30:53,920 --> 00:30:56,760
Speaker 1: Like does the theory that predict cosmic strings also predict

645
00:30:56,840 --> 00:30:59,680
Speaker 1: black holes or are they sort of mutually exclusive.

646
00:31:00,080 --> 00:31:02,320
Speaker 2: Now, in the theory where you have cosmic strings, you

647
00:31:02,440 --> 00:31:05,280
Speaker 2: also are allowed to have black holes. Yes, we don't

648
00:31:05,320 --> 00:31:07,280
Speaker 2: know if cosmic strings are real, we could look for

649
00:31:07,320 --> 00:31:11,080
Speaker 2: them with gravitational lensing gravitational waves of their own, because

650
00:31:11,120 --> 00:31:13,800
Speaker 2: we think they're dynamic. They can like wiggle and whip

651
00:31:13,840 --> 00:31:16,760
Speaker 2: around and stuff. But of course we've never seen one.

652
00:31:16,840 --> 00:31:19,240
Speaker 1: Well technically, we don't even know if black holes are real.

653
00:31:19,640 --> 00:31:23,560
Speaker 2: Yeah, technically that's true. There are some very compact massive objects,

654
00:31:23,560 --> 00:31:26,160
Speaker 2: but we don't know if they actually are general relativistic

655
00:31:26,200 --> 00:31:27,480
Speaker 2: black holes or something else.

656
00:31:27,920 --> 00:31:29,840
Speaker 1: All right, well, then what would happen if you have

657
00:31:29,960 --> 00:31:34,120
Speaker 1: this crack the spaghetti of super primorial energy hitting a

658
00:31:34,160 --> 00:31:36,880
Speaker 1: black hole. Wouldn't the black hole just win?

659
00:31:37,840 --> 00:31:40,480
Speaker 2: Probably that's what would happen, because black holes always win.

660
00:31:40,920 --> 00:31:43,520
Speaker 2: I mean, they are event horizons. So cosmic strings and

661
00:31:43,560 --> 00:31:45,680
Speaker 2: the cosmic string is just like a tube of super

662
00:31:45,760 --> 00:31:48,840
Speaker 2: high energy density, and so it probably just gets slurped

663
00:31:48,920 --> 00:31:51,720
Speaker 2: up and make it for like a really monster black hole.

664
00:31:52,320 --> 00:31:55,240
Speaker 1: Or could the string maybe like slice the black hole apart?

665
00:31:55,600 --> 00:31:58,240
Speaker 1: Is that a possibility? Like it? Because these strings aren't

666
00:31:58,280 --> 00:32:00,720
Speaker 1: just sitting out there, they're also bending space and time

667
00:32:00,760 --> 00:32:03,400
Speaker 1: around them, right like they're super extreme. I think we've

668
00:32:03,440 --> 00:32:06,160
Speaker 1: talked about maybe like doing a lub arond one of

669
00:32:06,200 --> 00:32:08,160
Speaker 1: these and going back in time and things like that.

670
00:32:08,240 --> 00:32:11,320
Speaker 1: Couldn't one of these strings just kind of like disrupt

671
00:32:11,320 --> 00:32:11,880
Speaker 1: a black hole.

672
00:32:11,960 --> 00:32:14,680
Speaker 2: There's one way to theoretically go back in time, which

673
00:32:14,680 --> 00:32:18,720
Speaker 2: involves doing orbits around an infinite string of cosmic dust,

674
00:32:18,880 --> 00:32:20,960
Speaker 2: But that's a different kind of string. That's a third

675
00:32:21,160 --> 00:32:25,440
Speaker 2: kind of string. But could cosmic strings slice a black

676
00:32:25,440 --> 00:32:28,719
Speaker 2: hole in half? I don't think so, because cosmic strings

677
00:32:28,760 --> 00:32:32,000
Speaker 2: are just energy density. Although there are energy density where

678
00:32:32,080 --> 00:32:34,080
Speaker 2: the rules of the universe are in a different phase,

679
00:32:34,120 --> 00:32:37,560
Speaker 2: those quantum fields are still very, very high, but there's

680
00:32:37,560 --> 00:32:40,320
Speaker 2: something about them that's preserving that there's like a crack

681
00:32:40,400 --> 00:32:43,320
Speaker 2: in space itself, is an interface there that's keeping this

682
00:32:43,360 --> 00:32:46,680
Speaker 2: from just like diffusing out into space, and so the

683
00:32:46,760 --> 00:32:49,240
Speaker 2: rules are a little bit different. But my money would

684
00:32:49,280 --> 00:32:51,640
Speaker 2: be on the cosmic string getting gobbled by the black hole.

685
00:32:51,840 --> 00:32:53,320
Speaker 2: You never bet against the black hole.

686
00:32:53,960 --> 00:32:56,600
Speaker 1: But a cosmic string, isn't it super long? So would

687
00:32:56,600 --> 00:32:59,520
Speaker 1: it just get split in half? Or what would happen?

688
00:33:00,040 --> 00:33:01,880
Speaker 1: Would it get disrupted by the black hole and then

689
00:33:02,000 --> 00:33:02,920
Speaker 1: rejoin up again.

690
00:33:03,440 --> 00:33:05,920
Speaker 2: They can be super duper long, like maybe one hundred

691
00:33:06,000 --> 00:33:08,480
Speaker 2: billion light years, but if a black hole hits the

692
00:33:08,480 --> 00:33:10,680
Speaker 2: middle of it, it would just start slurping it from both sides.

693
00:33:10,760 --> 00:33:12,440
Speaker 2: It's like if you eat a piece of spaghetti from

694
00:33:12,440 --> 00:33:14,200
Speaker 2: the middle and you can just slurp both ends in.

695
00:33:14,680 --> 00:33:17,640
Speaker 1: Oh, this cosmic string is a thing, like you can move.

696
00:33:17,880 --> 00:33:20,360
Speaker 2: Yes, yeah, they can whip around and slide through space

697
00:33:20,400 --> 00:33:23,800
Speaker 2: absolutely and make gravitational waves, which is how we might

698
00:33:23,880 --> 00:33:25,280
Speaker 2: one day be able to detect them.

699
00:33:25,320 --> 00:33:28,160
Speaker 1: It would slur But interesting. But isn't it like a

700
00:33:28,160 --> 00:33:29,120
Speaker 1: feature of space?

701
00:33:29,640 --> 00:33:32,200
Speaker 2: Yes, but everything's a feature of space. You're a feature

702
00:33:32,200 --> 00:33:34,480
Speaker 2: of space. I'm a feature of space, right.

703
00:33:34,520 --> 00:33:36,200
Speaker 1: Like I guess I mean, like when it gets slurred

704
00:33:36,240 --> 00:33:38,120
Speaker 1: by the black hole, Like, can it move through space?

705
00:33:38,160 --> 00:33:39,600
Speaker 1: If it's a feature of space.

706
00:33:39,520 --> 00:33:41,719
Speaker 2: You can move through space the same way that we can. Right,

707
00:33:41,800 --> 00:33:44,240
Speaker 2: We're just like our energy slides through the quantum fields

708
00:33:44,280 --> 00:33:47,880
Speaker 2: that feel all of space. Cosmic strings can also move,

709
00:33:48,000 --> 00:33:50,200
Speaker 2: so it's sort of like persistent in that way. They

710
00:33:50,240 --> 00:33:53,280
Speaker 2: don't just diffuse out into nothing. They persist and move

711
00:33:53,360 --> 00:33:55,640
Speaker 2: through space, keeping their structure m.

712
00:33:57,240 --> 00:33:59,760
Speaker 1: All right. So then I guess that answers Dan's question.

713
00:34:00,200 --> 00:34:02,760
Speaker 1: Your best guess is that the black hole wins. It

714
00:34:02,840 --> 00:34:07,920
Speaker 1: slurps up the cosmic string like a string of bugatoni pasta.

715
00:34:08,280 --> 00:34:10,839
Speaker 2: That's right, because as dense as the cosmic string is,

716
00:34:11,000 --> 00:34:13,479
Speaker 2: it's not dense enough to make its own black hole.

717
00:34:13,640 --> 00:34:16,400
Speaker 2: So it's probably less dense than the black hole, and

718
00:34:16,440 --> 00:34:18,759
Speaker 2: that's why the black hole wins. And even if the

719
00:34:18,800 --> 00:34:21,440
Speaker 2: cosmic string was dense enough to make like a black

720
00:34:21,600 --> 00:34:24,680
Speaker 2: line of singularities, that would also just be a black hole,

721
00:34:25,080 --> 00:34:27,840
Speaker 2: and black hole plus black hole means black hole, it.

722
00:34:27,840 --> 00:34:32,440
Speaker 1: Would be a black line or black pasta.

723
00:34:31,680 --> 00:34:33,840
Speaker 2: Squid pasta cosmic squid pasta.

724
00:34:34,200 --> 00:34:38,080
Speaker 1: There you go, a new recipe for the universe. All right, well,

725
00:34:38,080 --> 00:34:40,319
Speaker 1: thank you Dane for that question. Now let's get to

726
00:34:40,360 --> 00:34:44,240
Speaker 1: our third question, and this one is about Daniel's favorite topic,

727
00:34:44,680 --> 00:34:48,960
Speaker 1: aliens and also nano things, and so let's get to

728
00:34:49,000 --> 00:35:04,279
Speaker 1: that question. But first let's take a quick break. All right,

729
00:35:04,320 --> 00:35:06,920
Speaker 1: we're answering listener questions here today, and our last question

730
00:35:07,000 --> 00:35:08,880
Speaker 1: of the day comes from I'll be.

731
00:35:09,520 --> 00:35:14,279
Speaker 3: Hi, Daniel and Jorge. In trying to communicate with extraterrestrials,

732
00:35:14,719 --> 00:35:18,880
Speaker 3: we need to demonstrate that our signals are intelligent. We

733
00:35:19,000 --> 00:35:22,720
Speaker 3: can't broadcast, say the speed of light or the ground

734
00:35:22,880 --> 00:35:27,719
Speaker 3: energy of hydrogen using our preferred units like meters per

735
00:35:27,760 --> 00:35:33,000
Speaker 3: second or electron volts because who's to say that ET

736
00:35:33,280 --> 00:35:38,920
Speaker 3: doesn't measure speeds in quad lutes per nano. Now, how

737
00:35:38,960 --> 00:35:42,600
Speaker 3: do we then demonstrate in a unit free or natural

738
00:35:42,719 --> 00:35:44,560
Speaker 3: way that we know stuff?

739
00:35:45,360 --> 00:35:48,680
Speaker 1: All right? Interesting question. I feel like this is a

740
00:35:48,760 --> 00:35:50,440
Speaker 1: question about how to talk to aliens.

741
00:35:50,880 --> 00:35:54,240
Speaker 2: Yeah, basically, how do we convince aliens that we're smart,

742
00:35:54,400 --> 00:35:56,920
Speaker 2: that we're here. How do you send a message to

743
00:35:57,000 --> 00:35:59,359
Speaker 2: aliens that when they read it they're like, oh yeah,

744
00:35:59,400 --> 00:36:01,480
Speaker 2: those guys know they're doing or there are even people

745
00:36:01,520 --> 00:36:02,240
Speaker 2: out there.

746
00:36:02,280 --> 00:36:05,840
Speaker 1: Like how do we pass the test? Like, if you

747
00:36:05,880 --> 00:36:08,839
Speaker 1: want to talk math to aliens, I think obvious question

748
00:36:09,000 --> 00:36:12,000
Speaker 1: is like what sort of units would you use if

749
00:36:12,040 --> 00:36:15,120
Speaker 1: you can? Are there like units that they would recognize?

750
00:36:16,400 --> 00:36:19,160
Speaker 2: Yeah, it's a really cool question. There's a couple directions

751
00:36:19,400 --> 00:36:21,839
Speaker 2: to go with this, like could you come up with

752
00:36:22,000 --> 00:36:25,840
Speaker 2: numbers that don't need units? Are there physical numbers in

753
00:36:25,880 --> 00:36:29,600
Speaker 2: the universe that are unit lists? Because He's right, units

754
00:36:29,600 --> 00:36:31,840
Speaker 2: are things we made up, you know, Like the speed

755
00:36:31,880 --> 00:36:34,600
Speaker 2: of light is three times ten of the eight meters

756
00:36:34,640 --> 00:36:37,520
Speaker 2: per second, But that number three times ten of eight

757
00:36:37,680 --> 00:36:39,360
Speaker 2: is only that number because of the length of a

758
00:36:39,400 --> 00:36:41,840
Speaker 2: meter in the length of a second. If you change

759
00:36:41,880 --> 00:36:43,400
Speaker 2: that to something else, the speed of light would be

760
00:36:43,400 --> 00:36:45,680
Speaker 2: a different numbers. You can't just send that number without

761
00:36:45,680 --> 00:36:48,600
Speaker 2: explaining where the units are. The units are just something

762
00:36:48,640 --> 00:36:49,880
Speaker 2: we invented, right.

763
00:36:49,960 --> 00:36:52,120
Speaker 1: Yeah, And I think we don't even know exactly what

764
00:36:52,200 --> 00:36:54,560
Speaker 1: a meter is or it's like it's a little bit

765
00:36:55,080 --> 00:36:56,960
Speaker 1: somewhat arbitrary or changeable.

766
00:36:57,040 --> 00:36:58,680
Speaker 2: It used to be that a meter was length of

767
00:36:58,719 --> 00:37:01,360
Speaker 2: some platinum rod in Paris, But then people finally realize

768
00:37:01,440 --> 00:37:04,840
Speaker 2: that's ridiculous because Paris has different weather, and so the

769
00:37:04,920 --> 00:37:07,360
Speaker 2: rod gets longer and shorter, and we all get like

770
00:37:07,480 --> 00:37:10,960
Speaker 2: taller and shorter as that happens. Now they define the

771
00:37:11,000 --> 00:37:13,520
Speaker 2: meter in terms of the speed of light, how far

772
00:37:13,719 --> 00:37:15,480
Speaker 2: light goes in a certain amount of time.

773
00:37:15,920 --> 00:37:18,200
Speaker 1: Even the units of time are oursho arbitrary, right, Like

774
00:37:18,239 --> 00:37:20,880
Speaker 1: a second which is one sixty eight of a minute

775
00:37:20,880 --> 00:37:22,879
Speaker 1: and sixty of an hour and twenty fourth of a day.

776
00:37:23,680 --> 00:37:25,920
Speaker 1: That's arbitrary, right, like we could have twenty four hours

777
00:37:25,920 --> 00:37:26,319
Speaker 1: in a day.

778
00:37:26,440 --> 00:37:29,239
Speaker 2: The units of time are arbitrary, You're absolutely right. We

779
00:37:29,360 --> 00:37:32,120
Speaker 2: just made them up. But they are all so physical,

780
00:37:32,560 --> 00:37:35,920
Speaker 2: Like we define the second in terms of oscillations of

781
00:37:35,960 --> 00:37:39,000
Speaker 2: an atom, and when atom oscillates a certain number of times,

782
00:37:39,040 --> 00:37:41,320
Speaker 2: we call that a second. That's a new definition of

783
00:37:41,360 --> 00:37:44,759
Speaker 2: a second. So one approach to making something universal is

784
00:37:44,800 --> 00:37:46,920
Speaker 2: to say, let's just get rid of units altogether, and

785
00:37:46,960 --> 00:37:49,000
Speaker 2: we can talk about that. The other approach is to

786
00:37:49,040 --> 00:37:51,560
Speaker 2: make the units physicals and say, like, look, here's a

787
00:37:51,680 --> 00:37:55,439
Speaker 2: very natural choice for a clock. Let's use that as

788
00:37:55,480 --> 00:37:58,240
Speaker 2: our definition of time and hope the aliens follow along.

789
00:37:58,680 --> 00:38:00,239
Speaker 2: That's actually what Carl say, you can try. I had

790
00:38:00,239 --> 00:38:02,919
Speaker 2: to do on the Pioneer plaque. This plaque that went

791
00:38:02,960 --> 00:38:05,319
Speaker 2: on the Pioneer probe and was sent out into deep

792
00:38:05,400 --> 00:38:08,560
Speaker 2: space and is right now zooming out towards aliens.

793
00:38:08,920 --> 00:38:10,759
Speaker 1: Yeah. I think that was in that movie Contact too,

794
00:38:10,840 --> 00:38:13,200
Speaker 1: wasn't it. Like they use the hydrogen atom as a

795
00:38:13,239 --> 00:38:16,160
Speaker 1: sort of like baseline, and you make a drawing of

796
00:38:16,160 --> 00:38:18,440
Speaker 1: the hydrogen atom and hopefully the aliens will be like, oh,

797
00:38:18,440 --> 00:38:21,279
Speaker 1: that's a hydrogen atom, and from there you can kind

798
00:38:21,280 --> 00:38:23,320
Speaker 1: of figure out units of time and length.

799
00:38:23,640 --> 00:38:26,880
Speaker 2: Yeah, exactly. There's a spin flip transition. The electron has

800
00:38:26,920 --> 00:38:29,359
Speaker 2: a certain spin and it can sometimes flip from one

801
00:38:29,400 --> 00:38:32,160
Speaker 2: spin to the other spin, and it's very well known

802
00:38:32,239 --> 00:38:35,040
Speaker 2: time from a very basic thing in the universe. Hydrogen

803
00:38:35,160 --> 00:38:38,480
Speaker 2: is like most of the universe. So if you can

804
00:38:38,520 --> 00:38:42,480
Speaker 2: somehow describe hydrogen and describe this spin flip and communicate

805
00:38:42,560 --> 00:38:44,880
Speaker 2: to the aliens like, look, can we all agree that

806
00:38:44,960 --> 00:38:47,279
Speaker 2: this is a basic unit of time, then you can

807
00:38:47,280 --> 00:38:49,879
Speaker 2: start to talk about things that take time. And then

808
00:38:49,920 --> 00:38:51,479
Speaker 2: you can use like the speed of light. The speed

809
00:38:51,520 --> 00:38:54,760
Speaker 2: of light helps you relate meters and seconds, right, relates

810
00:38:54,800 --> 00:38:57,960
Speaker 2: distance and time, and so from there you could build

811
00:38:58,040 --> 00:39:00,960
Speaker 2: up what you imagine would be me be a universal

812
00:39:01,000 --> 00:39:04,600
Speaker 2: set of units, one at least other science minded aliens

813
00:39:04,760 --> 00:39:06,200
Speaker 2: might understand.

814
00:39:06,160 --> 00:39:09,440
Speaker 1: Right, And that doesn't depend on the conditions of the hydrogen.

815
00:39:09,520 --> 00:39:12,400
Speaker 1: Like if you hot hydrogen and cold hydrogen, they all

816
00:39:12,719 --> 00:39:13,600
Speaker 1: have the same timing.

817
00:39:13,800 --> 00:39:16,160
Speaker 2: This is foreign electron in the lowest state. But you

818
00:39:16,200 --> 00:39:19,120
Speaker 2: know that's pretty common, and we think anybody who studies

819
00:39:19,160 --> 00:39:23,480
Speaker 2: hydrogen is going to understand this transition. It's pretty well known.

820
00:39:24,040 --> 00:39:26,200
Speaker 2: But you know, there are a lot of assumptions there,

821
00:39:26,239 --> 00:39:28,600
Speaker 2: like that the aliens are doing science, that they understand

822
00:39:28,600 --> 00:39:31,960
Speaker 2: we're talking about hydrogen, that they think about time the

823
00:39:32,000 --> 00:39:35,240
Speaker 2: same way we do. There's a lot of things built

824
00:39:35,239 --> 00:39:36,760
Speaker 2: into that, right, right.

825
00:39:36,600 --> 00:39:39,799
Speaker 1: But I think you're saying that like units is maybe

826
00:39:39,840 --> 00:39:42,480
Speaker 1: not the biggest of our problems in communicating with aliens.

827
00:39:42,600 --> 00:39:44,320
Speaker 2: Yeah, you could even get rid of units, and you

828
00:39:44,320 --> 00:39:46,600
Speaker 2: could say, look, are there numbers in the universe that

829
00:39:46,680 --> 00:39:50,000
Speaker 2: don't have units? And there are absolutely, Like in our

830
00:39:50,120 --> 00:39:53,480
Speaker 2: theories of physics, there are numbers that define the theory

831
00:39:53,840 --> 00:39:55,920
Speaker 2: that if you change those numbers, you get a different

832
00:39:55,920 --> 00:39:58,799
Speaker 2: description in the universe. And those numbers don't have any

833
00:39:58,880 --> 00:40:02,520
Speaker 2: units to them. Is pure numbers, and so if you

834
00:40:02,560 --> 00:40:05,720
Speaker 2: wanted to communicate to aliens that were also doing physics

835
00:40:05,719 --> 00:40:08,000
Speaker 2: the way we were, then you might want to communicate

836
00:40:08,120 --> 00:40:12,320
Speaker 2: those numbers. And an example is like the cosmological constant,

837
00:40:12,560 --> 00:40:15,640
Speaker 2: which we think is what's controlling the expansion of the universe.

838
00:40:15,680 --> 00:40:17,920
Speaker 2: That's a number we can measure it. It doesn't have

839
00:40:18,040 --> 00:40:18,840
Speaker 2: any units.

840
00:40:19,239 --> 00:40:21,240
Speaker 1: It doesn't have any units because it's like a ratio

841
00:40:21,600 --> 00:40:22,920
Speaker 1: of something, right.

842
00:40:22,880 --> 00:40:24,960
Speaker 2: Like any number that doesn't have units, you can calculate

843
00:40:25,000 --> 00:40:29,080
Speaker 2: them from ratios. But most naturally they're just numbers, you know.

844
00:40:29,200 --> 00:40:31,960
Speaker 2: Like other examples of things are like the coupling of

845
00:40:32,000 --> 00:40:34,759
Speaker 2: particles to other particles. These are just numbers that go

846
00:40:34,840 --> 00:40:37,640
Speaker 2: in our quantum field theory. They don't have units to them.

847
00:40:38,040 --> 00:40:40,680
Speaker 2: Like every particle that gets mass from the Higgs, there's

848
00:40:40,680 --> 00:40:43,520
Speaker 2: a number associated with that particle, and it controls how

849
00:40:43,600 --> 00:40:46,520
Speaker 2: much mass that particle gets. That's just a number, like

850
00:40:46,560 --> 00:40:48,680
Speaker 2: the top quark has a number, the bottom pork is

851
00:40:48,680 --> 00:40:50,719
Speaker 2: a number, the electron has a number. It's just a

852
00:40:50,760 --> 00:40:52,640
Speaker 2: pure number with no units whatsoever.

853
00:40:53,400 --> 00:40:55,799
Speaker 1: Is it kind of like pi, which is, you know,

854
00:40:56,520 --> 00:40:58,040
Speaker 1: like a feature of geometry.

855
00:40:58,160 --> 00:40:58,399
Speaker 5: Hmm.

856
00:40:59,440 --> 00:41:01,920
Speaker 2: That's another an example. You could use the number of

857
00:41:01,960 --> 00:41:05,759
Speaker 2: spatial dimensions. That's a pure number that describes our understanding

858
00:41:05,800 --> 00:41:08,279
Speaker 2: of the geometry of the universe. Pie is another great

859
00:41:08,280 --> 00:41:11,480
Speaker 2: one because pie is a ratio that works in flat space,

860
00:41:12,160 --> 00:41:14,520
Speaker 2: Like if you live in curve space, the ratio between

861
00:41:14,520 --> 00:41:17,799
Speaker 2: the radius and the circumference of a circle actually isn't pie.

862
00:41:18,520 --> 00:41:20,640
Speaker 2: So there are these numbers that are special that are

863
00:41:20,640 --> 00:41:22,640
Speaker 2: important to the understanding of the universe that don't have

864
00:41:22,680 --> 00:41:25,560
Speaker 2: any units at all. You could try to communicate those.

865
00:41:26,120 --> 00:41:28,960
Speaker 2: But even still, as you were saying, you have a problem,

866
00:41:29,000 --> 00:41:32,000
Speaker 2: like how do you communicate numbers to a bunch of aliens.

867
00:41:32,080 --> 00:41:34,600
Speaker 1: Well, I would imagine maybe you like use one finger

868
00:41:34,640 --> 00:41:37,879
Speaker 1: for one, Like if there are aliens living in the universe,

869
00:41:37,880 --> 00:41:40,200
Speaker 1: they are probably familiar with the concept of a unit, right,

870
00:41:40,239 --> 00:41:42,600
Speaker 1: like one, two, three, And then you build up a

871
00:41:42,680 --> 00:41:43,919
Speaker 1: number system from that, right.

872
00:41:44,080 --> 00:41:46,000
Speaker 2: I think Abby was not talking about aliens that have

873
00:41:46,120 --> 00:41:48,239
Speaker 2: arrived here on Earth that we're interacting with, and you

874
00:41:48,280 --> 00:41:51,000
Speaker 2: can point two apples and say one apple, two apples,

875
00:41:51,040 --> 00:41:55,719
Speaker 2: three apples, But communicating with extraterrestrials like broadcasting a message

876
00:41:56,200 --> 00:41:57,600
Speaker 2: the way that we have done in the way that

877
00:41:57,640 --> 00:41:59,120
Speaker 2: like the pie Ineer plaque, is like, how do you

878
00:41:59,120 --> 00:42:01,040
Speaker 2: build this in and end it out to the universe

879
00:42:01,200 --> 00:42:04,200
Speaker 2: so you can be understood without us, so that somebody

880
00:42:04,280 --> 00:42:06,399
Speaker 2: out there getting that message, you'd be like, oh, look,

881
00:42:06,440 --> 00:42:07,719
Speaker 2: there's smart people over there.

882
00:42:08,040 --> 00:42:11,680
Speaker 1: Mmm, Like how do you basically communicate in mores quote

883
00:42:11,760 --> 00:42:13,120
Speaker 1: kind of yeah?

884
00:42:13,239 --> 00:42:15,200
Speaker 2: How do you encode a signal? So if you're sending

885
00:42:15,280 --> 00:42:17,759
Speaker 2: radio waves to the universe, how do you modulate the

886
00:42:17,760 --> 00:42:21,080
Speaker 2: frequency or the pulses or whatever to send a message

887
00:42:21,160 --> 00:42:24,080
Speaker 2: that indicates, Look, we're smart physics people over here. They

888
00:42:24,080 --> 00:42:26,120
Speaker 2: don't know how to name anything, but we are making

889
00:42:26,160 --> 00:42:27,960
Speaker 2: some progress and understanding the universe.

890
00:42:28,800 --> 00:42:30,600
Speaker 1: Wasn't that in the movie Contact Too? I feel like

891
00:42:30,640 --> 00:42:33,160
Speaker 1: we're referencing this movie a lot, But wasn't that part

892
00:42:33,200 --> 00:42:35,560
Speaker 1: of the signal we got from aliens? Like there was

893
00:42:35,640 --> 00:42:38,480
Speaker 1: a certain number of pulses and the number of pulses

894
00:42:38,560 --> 00:42:40,879
Speaker 1: followed the digits of pie or something like that.

895
00:42:41,440 --> 00:42:43,839
Speaker 2: Yeah. Absolutely, And you're touching on the core issue, which

896
00:42:43,920 --> 00:42:47,320
Speaker 2: is in the end, any message you send is symbols

897
00:42:47,360 --> 00:42:51,600
Speaker 2: like pulses or digits or wiggles or whatever. They only

898
00:42:51,640 --> 00:42:54,520
Speaker 2: represent the pure idea. There's a connection between the idea

899
00:42:54,560 --> 00:42:57,680
Speaker 2: in your head and the idea in these symbols. But

900
00:42:57,760 --> 00:43:00,759
Speaker 2: the symbols themselves are actually kind of arbitrar You come

901
00:43:00,840 --> 00:43:03,440
Speaker 2: up with lots of different ways to enclode the same

902
00:43:03,640 --> 00:43:06,759
Speaker 2: idea in order to decode it, to look at the

903
00:43:06,800 --> 00:43:09,480
Speaker 2: symbols and have the idea in your mind, you need

904
00:43:09,520 --> 00:43:12,120
Speaker 2: to have some commonality. You need to have some frame

905
00:43:12,160 --> 00:43:15,080
Speaker 2: of reference to say, oh, maybe this is how they're

906
00:43:15,080 --> 00:43:18,000
Speaker 2: doing it. Which is why it's so challenging to look

907
00:43:18,080 --> 00:43:21,200
Speaker 2: at the sky and understand whether there are signals from aliens,

908
00:43:21,239 --> 00:43:23,440
Speaker 2: because there's so many different ways they could encode it

909
00:43:23,520 --> 00:43:26,080
Speaker 2: or represent it. We might just be totally missing it.

910
00:43:26,920 --> 00:43:29,399
Speaker 1: Well, I feel like all these questions has maybe two

911
00:43:29,480 --> 00:43:32,200
Speaker 1: dimensions to it, Like one is, how do we just

912
00:43:32,360 --> 00:43:35,160
Speaker 1: demonstrate that we're smart and that we know stuff about

913
00:43:35,160 --> 00:43:37,640
Speaker 1: the universe? And the other one is like how do

914
00:43:37,680 --> 00:43:40,640
Speaker 1: you actually have a conversation about physics with an alien?

915
00:43:40,880 --> 00:43:42,600
Speaker 1: Like if you just wanted to demonstrate, like, hey, we

916
00:43:42,680 --> 00:43:45,440
Speaker 1: know math and we know things about the universe, Like

917
00:43:45,480 --> 00:43:47,800
Speaker 1: you could just send the digits of pie as pulses,

918
00:43:47,880 --> 00:43:50,799
Speaker 1: and somebody would have to interpret that as saying, wait,

919
00:43:50,800 --> 00:43:53,000
Speaker 1: this is not a random sequence of pulses. This is

920
00:43:53,000 --> 00:43:55,439
Speaker 1: a secreence of pulses that followed the digits of pie.

921
00:43:55,680 --> 00:43:57,960
Speaker 2: But you'd also have to figure out how to encode digits,

922
00:43:57,960 --> 00:44:00,880
Speaker 2: like how do you represent different digits in terms of pulses?

923
00:44:01,120 --> 00:44:03,319
Speaker 2: That right, there is an encoding scheme, and that's going

924
00:44:03,360 --> 00:44:05,560
Speaker 2: to be cultural, that's going to be symbolic, that's going

925
00:44:05,640 --> 00:44:08,239
Speaker 2: to be fundamentally arbitrary. So you have to do it

926
00:44:08,280 --> 00:44:10,360
Speaker 2: in a way that you think they could reverse engineer.

927
00:44:10,640 --> 00:44:12,759
Speaker 1: Oh, I see what we're say, Because you're saying, like

928
00:44:12,800 --> 00:44:16,719
Speaker 1: the digits of Pi assumes a base of ten, maybe

929
00:44:16,719 --> 00:44:18,760
Speaker 1: the aliens are doing base of fifty.

930
00:44:18,840 --> 00:44:21,040
Speaker 2: Yeah, so how do you send the number four? Right?

931
00:44:21,760 --> 00:44:23,759
Speaker 2: You break it down into binary? All right, but you

932
00:44:23,840 --> 00:44:26,319
Speaker 2: know you're assuming that they understand that they know what

933
00:44:26,400 --> 00:44:28,160
Speaker 2: it won is in a zero and all this stuff.

934
00:44:28,239 --> 00:44:30,680
Speaker 1: Well, if you send four pulses. Wouldn't that be four

935
00:44:30,719 --> 00:44:33,160
Speaker 1: in any number system.

936
00:44:33,280 --> 00:44:35,399
Speaker 2: Yeah, if you're counting the pulses and that's the way

937
00:44:35,400 --> 00:44:38,960
Speaker 2: you're representing it. You're talking about like a unary number system,

938
00:44:39,200 --> 00:44:42,279
Speaker 2: you know, where you just have like one digit, and

939
00:44:42,360 --> 00:44:44,240
Speaker 2: that's cool. But then they have to know to interpret

940
00:44:44,280 --> 00:44:47,919
Speaker 2: your message that way that it doesn't mean something totally different. Right.

941
00:44:48,400 --> 00:44:50,359
Speaker 2: If you know that what system somebody is using, it's

942
00:44:50,360 --> 00:44:52,759
Speaker 2: not so hard to decode their message. But if you

943
00:44:52,840 --> 00:44:55,960
Speaker 2: have no idea, then you don't know. We actually talked

944
00:44:55,960 --> 00:44:57,920
Speaker 2: to a philosopher on the podcast like a year ago

945
00:44:58,280 --> 00:45:02,400
Speaker 2: who argue that it's probably impossible without any cultural context

946
00:45:02,560 --> 00:45:05,120
Speaker 2: to know for sure what aliens are saying. You might

947
00:45:05,160 --> 00:45:07,160
Speaker 2: get a message and decode it and you don't have

948
00:45:07,200 --> 00:45:08,799
Speaker 2: no idea what they're trying to say, So you have

949
00:45:08,800 --> 00:45:11,120
Speaker 2: no idea whether you've done it right. You could be

950
00:45:11,200 --> 00:45:13,440
Speaker 2: lucky and be like, oh my gosh, I'm guessing this

951
00:45:13,640 --> 00:45:15,400
Speaker 2: encoding and it turns out to give me all the

952
00:45:15,400 --> 00:45:18,360
Speaker 2: digits of pie that must be right. That would be

953
00:45:18,360 --> 00:45:21,879
Speaker 2: a cool experience. You essentially have to randomly guess how

954
00:45:21,880 --> 00:45:24,759
Speaker 2: they're encoding their message, or in reverse, they would have

955
00:45:24,800 --> 00:45:26,480
Speaker 2: to guess.

956
00:45:25,120 --> 00:45:29,320
Speaker 1: How Yeah, because I guess even three, one, four, one, five, whatever,

957
00:45:29,760 --> 00:45:33,439
Speaker 1: the digits of pie, that's only those numbers. If you're

958
00:45:33,520 --> 00:45:38,560
Speaker 1: using the same base ten system that we do, right,

959
00:45:38,719 --> 00:45:42,680
Speaker 1: Like PI in binary is totally different. Yeah, exactly, all right,

960
00:45:42,719 --> 00:45:45,600
Speaker 1: So then what's the answer for albi? It's hopeless, forget

961
00:45:45,600 --> 00:45:46,000
Speaker 1: about it.

962
00:45:47,400 --> 00:45:49,000
Speaker 2: The answer is that it's not hopeless if we have

963
00:45:49,040 --> 00:45:51,560
Speaker 2: a lot in common with the aliens. I mean, if

964
00:45:51,600 --> 00:45:54,120
Speaker 2: there are human like aliens doing human like science and

965
00:45:54,120 --> 00:45:56,239
Speaker 2: a human like way, then we can just send them

966
00:45:56,239 --> 00:45:58,720
Speaker 2: a text basically and they'll get it and understand it.

967
00:45:58,760 --> 00:46:00,360
Speaker 1: They'd be like, who is number?

968
00:46:00,960 --> 00:46:03,400
Speaker 2: Yeah. The more we have in common with them, the

969
00:46:03,440 --> 00:46:05,279
Speaker 2: easier it is for them to understand us and for

970
00:46:05,400 --> 00:46:08,640
Speaker 2: us to understand them. The real question is how much

971
00:46:08,640 --> 00:46:11,759
Speaker 2: in common do we have with them. The most interesting

972
00:46:11,840 --> 00:46:14,480
Speaker 2: aliens are the ones that have the least in common

973
00:46:14,520 --> 00:46:17,120
Speaker 2: with us, that have like evolved in some weird situation

974
00:46:17,360 --> 00:46:20,480
Speaker 2: or doing science in some totally different way using not

975
00:46:20,560 --> 00:46:23,399
Speaker 2: even using mathematics or something. Those would be the ones

976
00:46:23,440 --> 00:46:26,080
Speaker 2: we could learn the most from about the universe. But

977
00:46:26,160 --> 00:46:28,799
Speaker 2: those would also probably be the ones it's hardest to

978
00:46:28,840 --> 00:46:32,760
Speaker 2: make contact with because they have different fundamental assumptions about

979
00:46:32,760 --> 00:46:35,640
Speaker 2: how to communicate and what encoding systems work and whether

980
00:46:35,640 --> 00:46:37,000
Speaker 2: they even use language.

981
00:46:37,040 --> 00:46:39,600
Speaker 1: You know, well, I mean that's sort of maybe according

982
00:46:39,640 --> 00:46:42,239
Speaker 1: to you. Maybe somebody else might argue that those are

983
00:46:42,280 --> 00:46:45,360
Speaker 1: the least useful aliens to talk to, Like, maybe the

984
00:46:45,400 --> 00:46:47,319
Speaker 1: more useful aliens to talk to might be the ones

985
00:46:47,360 --> 00:46:48,839
Speaker 1: that we do have things in common with.

986
00:46:48,920 --> 00:46:50,280
Speaker 2: Yeah, the ones that we have the most in common

987
00:46:50,280 --> 00:46:52,759
Speaker 2: with will definitely have fun stuff to talk about. That

988
00:46:52,840 --> 00:46:55,480
Speaker 2: philosophy we talk to about that scenario said, you have

989
00:46:55,560 --> 00:46:58,520
Speaker 2: to be careful though, because almost anything you say could

990
00:46:58,600 --> 00:47:01,640
Speaker 2: be interpreted as a Russian and the aliens could launch

991
00:47:01,640 --> 00:47:03,840
Speaker 2: a first strike. So the best thing to do in

992
00:47:03,840 --> 00:47:06,000
Speaker 2: that scenario is not to talk to aliens.

993
00:47:06,239 --> 00:47:08,239
Speaker 1: Oh boy, I feel like now you're getting into like

994
00:47:08,520 --> 00:47:13,319
Speaker 1: cosmic paranoia and the whole like, you know, the three

995
00:47:13,360 --> 00:47:16,760
Speaker 1: body problem of creatures in the forest scenario.

996
00:47:17,000 --> 00:47:18,880
Speaker 2: Yeah, it's a real concern, which.

997
00:47:18,719 --> 00:47:21,440
Speaker 1: Sounds like a whole different thing. Yeah, which maybe goes

998
00:47:21,480 --> 00:47:22,840
Speaker 1: outside of Albe's questions.

999
00:47:22,880 --> 00:47:25,799
Speaker 2: That's true. Yeah, maybe OBVI is not being responsible and

1000
00:47:25,880 --> 00:47:28,080
Speaker 2: just thinking I'm going to broadcast messages to aliens and

1001
00:47:28,120 --> 00:47:30,000
Speaker 2: I don't care if they want to kill us or not.

1002
00:47:30,440 --> 00:47:33,120
Speaker 2: But in that scenario where you don't worry about deathly aliens,

1003
00:47:33,360 --> 00:47:35,160
Speaker 2: then you should try lots of different schemes. You should

1004
00:47:35,160 --> 00:47:38,200
Speaker 2: talk to people from different cultures and have different ways

1005
00:47:38,200 --> 00:47:40,880
Speaker 2: of encoding it and representing it, hoping that one of

1006
00:47:40,920 --> 00:47:43,840
Speaker 2: them will overlap with the aliens. I think the best

1007
00:47:43,880 --> 00:47:47,759
Speaker 2: shot is to use numbers without units, because those are

1008
00:47:47,800 --> 00:47:51,160
Speaker 2: the ones that are the most universal, we think.

1009
00:47:50,920 --> 00:47:52,759
Speaker 1: At least, like we talked about it, Even if they

1010
00:47:52,800 --> 00:47:54,839
Speaker 1: don't have units, you don't know if they're you're using

1011
00:47:54,840 --> 00:47:56,640
Speaker 1: the same base numbers, right.

1012
00:47:56,600 --> 00:47:59,760
Speaker 2: Yeah, no, absolutely, there's always going to be a challenge

1013
00:47:59,760 --> 00:48:03,040
Speaker 2: there for how you represent those numbers in your message.

1014
00:48:03,520 --> 00:48:06,239
Speaker 2: But if they think similarly to us, maybe they'll unpuzzle it.

1015
00:48:06,239 --> 00:48:08,240
Speaker 2: You know, if there are smart enough aliens out there

1016
00:48:08,360 --> 00:48:10,560
Speaker 2: in might figure out how to crack the human code.

1017
00:48:10,680 --> 00:48:12,120
Speaker 1: Well, I guess I wonder if you could make an

1018
00:48:12,160 --> 00:48:16,080
Speaker 1: argument for like digital being maybe the one with the

1019
00:48:16,120 --> 00:48:18,560
Speaker 1: biggest shot at being universal. Like here on Earth we

1020
00:48:18,640 --> 00:48:21,960
Speaker 1: had base ten other bases, but ultimately we had to

1021
00:48:21,960 --> 00:48:25,600
Speaker 1: build computers. We built them out of binary Those are

1022
00:48:25,640 --> 00:48:25,880
Speaker 1: sort of.

1023
00:48:25,920 --> 00:48:28,719
Speaker 2: Most natural for us because they represent the states of

1024
00:48:28,760 --> 00:48:31,840
Speaker 2: the electronics on which our computers are built. Yeah, aliens

1025
00:48:31,840 --> 00:48:34,920
Speaker 2: could have like quantum computers as their first computing right,

1026
00:48:34,960 --> 00:48:37,640
Speaker 2: you never know, in which case binary doesn't really make sense.

1027
00:48:37,760 --> 00:48:40,600
Speaker 1: All right, Well, I guess then the answer for Auby

1028
00:48:40,800 --> 00:48:44,440
Speaker 1: is there isn't maybe a good way to do this

1029
00:48:44,560 --> 00:48:47,480
Speaker 1: to broadcast our intelligence, But that maybe doesn't mean that

1030
00:48:47,520 --> 00:48:49,919
Speaker 1: we shouldn't do it, right.

1031
00:48:50,200 --> 00:48:52,360
Speaker 2: Yeah, absolutely, we can broadcast things in a way that

1032
00:48:52,400 --> 00:48:54,520
Speaker 2: makes sense to us and hope that somebody out there

1033
00:48:54,600 --> 00:48:57,680
Speaker 2: gets it and here's our message and knows that we

1034
00:48:57,680 --> 00:49:00,640
Speaker 2: were for at least a little while here wondering about

1035
00:49:00,680 --> 00:49:02,520
Speaker 2: the universe and surviving Boba.

1036
00:49:02,719 --> 00:49:04,480
Speaker 1: Is that we could be like, we'll just speak English,

1037
00:49:04,560 --> 00:49:05,839
Speaker 1: let everyone else figure it out.

1038
00:49:06,480 --> 00:49:11,319
Speaker 2: It's very American, that's basically the approach. Yeah.

1039
00:49:11,960 --> 00:49:14,160
Speaker 1: All right, Well, thanks Aby for asking that question, and

1040
00:49:14,239 --> 00:49:17,120
Speaker 1: thanks to all of our question askers here today. I

1041
00:49:17,120 --> 00:49:20,680
Speaker 1: guess there's no end to human curiosity, for.

1042
00:49:20,760 --> 00:49:23,400
Speaker 2: Which we are eternally grateful. So if you are a

1043
00:49:23,440 --> 00:49:25,960
Speaker 2: curious person with questions about the universe, don't be shy

1044
00:49:26,040 --> 00:49:28,480
Speaker 2: and write them to us to questions at Daniel Andhorgey

1045
00:49:28,520 --> 00:49:29,120
Speaker 2: dot com.

1046
00:49:29,200 --> 00:49:31,719
Speaker 1: All right, we hope you enjoyed that. Thanks for joining us.

1047
00:49:32,400 --> 00:49:32,919
Speaker 1: See you next.

1048
00:49:32,920 --> 00:49:40,319
Speaker 2: Time for more science and curiosity. Come find us on

1049
00:49:40,360 --> 00:49:44,120
Speaker 2: social media, where we answer questions and post videos. We're

1050
00:49:44,120 --> 00:49:48,320
Speaker 2: on Twitter, Discord, Instant, and now TikTok. Thanks for listening

1051
00:49:48,320 --> 00:49:51,040
Speaker 2: and remember that Daniel and Jorge Explain the Universe is

1052
00:49:51,080 --> 00:49:55,680
Speaker 2: a production of iHeartRadio. For more podcasts from iHeartRadio, visit

1053
00:49:55,719 --> 00:49:59,759
Speaker 2: the iHeartRadio app, Apple Podcasts, or wherever you listen to

1054
00:49:59,800 --> 00:50:00,800
Speaker 2: your favorite shows.