1
00:00:08,440 --> 00:00:14,000
Speaker 1: Hey, or Hey, which superhero throws the hardest hunch? That's

2
00:00:14,000 --> 00:00:17,200
Speaker 1: a hard one. It's maybe either the Hulk or Superman,

3
00:00:17,320 --> 00:00:20,760
Speaker 1: all right? And then which superhero is the best at

4
00:00:21,000 --> 00:00:27,360
Speaker 1: taking a punch, either the Hulk or Superman. I thought

5
00:00:27,400 --> 00:00:29,400
Speaker 1: you might say the guy made a rubber But then

6
00:00:29,440 --> 00:00:34,880
Speaker 1: the obvious question is what happens when Superman punches the Hulk?

7
00:00:35,040 --> 00:00:38,280
Speaker 1: Oh man, you're making my comic book fan brain burst

8
00:00:38,159 --> 00:00:41,120
Speaker 1: in the light right now. I think mostly Hulk just

9
00:00:41,159 --> 00:00:45,479
Speaker 1: gets mad, you know. That's what he does, a shower

10
00:00:45,520 --> 00:00:49,120
Speaker 1: of bricks. It doesn't blow up the multiverse, Yeah it does,

11
00:00:49,280 --> 00:00:52,320
Speaker 1: but it burst into a shower of money for Marvel

12
00:00:52,400 --> 00:00:55,800
Speaker 1: and DC, money flowing from our wallets to theirs, and

13
00:00:55,880 --> 00:01:13,480
Speaker 1: the light going into my brain. Hi am for Hammed

14
00:01:13,520 --> 00:01:16,560
Speaker 1: cartoonists and the co author of Frequently Asked Questions about

15
00:01:16,600 --> 00:01:19,679
Speaker 1: the Universe. Hi. I'm Daniel. I'm a particle physicist and

16
00:01:19,720 --> 00:01:22,839
Speaker 1: a professor at uz Irvine, and I always fast forward

17
00:01:22,880 --> 00:01:26,160
Speaker 1: through the punching scenes in superhero movies. Always really, what

18
00:01:26,200 --> 00:01:28,600
Speaker 1: if you're at the theater? What do you do? Take

19
00:01:28,600 --> 00:01:31,920
Speaker 1: a quick nap? And then I run upstairs to the

20
00:01:31,920 --> 00:01:35,360
Speaker 1: projection booth. Force my way in and fast forward those scenes.

21
00:01:36,120 --> 00:01:39,000
Speaker 1: I see you get arrested his physically what you do know?

22
00:01:39,120 --> 00:01:41,240
Speaker 1: I tune them out because in the end, none of

23
00:01:41,240 --> 00:01:43,960
Speaker 1: it really matters. You know, A punches B, B punches A.

24
00:01:44,200 --> 00:01:47,160
Speaker 1: In the end, they're still around. There's no consequences to

25
00:01:47,240 --> 00:01:50,000
Speaker 1: the punching, right right, Yeah, it's kind of it's kind

26
00:01:50,000 --> 00:01:52,400
Speaker 1: of a cliche. I guess in superhero movies and sci

27
00:01:52,400 --> 00:01:54,880
Speaker 1: fi movies, you'd always end in a mano a mano,

28
00:01:55,040 --> 00:01:58,200
Speaker 1: right exactly. More houses get destroyed, some cars get flipped,

29
00:01:58,240 --> 00:02:02,400
Speaker 1: but nobody really gets hurt. All Sometimes sometimes the hero dies.

30
00:02:02,640 --> 00:02:05,200
Speaker 1: Sometimes here dies, but is it ever because of punching?

31
00:02:05,360 --> 00:02:08,720
Speaker 1: And usually they come back in the sequel. So but anyways,

32
00:02:08,760 --> 00:02:11,560
Speaker 1: Welcome to our podcast Daniel and Jorge Explain the Universe,

33
00:02:11,639 --> 00:02:13,880
Speaker 1: a production of My Heart Radio, in which we try

34
00:02:13,919 --> 00:02:17,919
Speaker 1: to punch through your confusion about the nature of our universe.

35
00:02:18,160 --> 00:02:20,320
Speaker 1: We try to knock down the walls that prevent you

36
00:02:20,360 --> 00:02:24,520
Speaker 1: from understanding how this incredible cosmos has come together, how

37
00:02:24,560 --> 00:02:27,120
Speaker 1: it's woven at the very smallest scale, how it works

38
00:02:27,160 --> 00:02:30,240
Speaker 1: at the very largest scales, and how the amazing emergent

39
00:02:30,320 --> 00:02:33,919
Speaker 1: properties that are me and you and our curiosity come

40
00:02:33,919 --> 00:02:37,360
Speaker 1: together to make this a wonderful universe to explore. That's right,

41
00:02:37,400 --> 00:02:39,799
Speaker 1: because there is something about human nature that makes us

42
00:02:39,840 --> 00:02:42,720
Speaker 1: mad when we don't understand how things work out there

43
00:02:42,720 --> 00:02:45,360
Speaker 1: in the cosmos, and it makes us turn dream to

44
00:02:45,360 --> 00:02:47,720
Speaker 1: think about that. Maybe there are aliens out there who

45
00:02:47,720 --> 00:02:50,240
Speaker 1: do understand what's going on, or maybe just future of

46
00:02:50,320 --> 00:02:54,280
Speaker 1: humans will understand. And here we are trapped in antiquity,

47
00:02:54,320 --> 00:02:57,720
Speaker 1: trapped in the ancient past, where humans are so clueless

48
00:02:57,800 --> 00:02:59,840
Speaker 1: about the nature of our universe. We don't know the

49
00:03:00,000 --> 00:03:03,639
Speaker 1: answer to basic questions about how it's put together, how

50
00:03:03,639 --> 00:03:05,960
Speaker 1: old is the universe, how long will the universe survive,

51
00:03:06,080 --> 00:03:07,840
Speaker 1: what's it made out of in the end, and how

52
00:03:07,880 --> 00:03:10,680
Speaker 1: do all the pieces of it work? After all? Why

53
00:03:10,720 --> 00:03:14,079
Speaker 1: are we so ignorant? Oh man, you're jealous of future physicists.

54
00:03:14,120 --> 00:03:16,120
Speaker 1: That's that's interesting. Do you put a little notes for

55
00:03:16,200 --> 00:03:19,000
Speaker 1: them in your papers? Like? I hope this helps you?

56
00:03:19,280 --> 00:03:23,360
Speaker 1: I roll every paper is just a note to future physicists, right,

57
00:03:23,400 --> 00:03:26,000
Speaker 1: That's exactly what it is. But yes, I am jealous

58
00:03:26,000 --> 00:03:28,280
Speaker 1: of future physicists. I wish that I could live forever

59
00:03:28,440 --> 00:03:31,880
Speaker 1: so that I could understand what they figure out. Sometimes

60
00:03:31,880 --> 00:03:34,639
Speaker 1: I dream about taking a time machine and going forward

61
00:03:34,760 --> 00:03:36,960
Speaker 1: just to steal like a child's astronomy book from the

62
00:03:37,040 --> 00:03:39,640
Speaker 1: year three thousand or ten thousand, so I could figure

63
00:03:39,640 --> 00:03:42,320
Speaker 1: out what it is that humanity has unraveled in the future.

64
00:03:42,360 --> 00:03:43,920
Speaker 1: I think you're assuming they're going to get it right.

65
00:03:44,280 --> 00:03:49,240
Speaker 1: What if they take, you know, cosmically wrong and those

66
00:03:49,360 --> 00:03:51,760
Speaker 1: children's books are are all, you know, made up. I

67
00:03:51,800 --> 00:03:54,520
Speaker 1: think that science always gets it wrong, but it's sort

68
00:03:54,520 --> 00:03:58,280
Speaker 1: of gently drifts towards more and more right. So I

69
00:03:58,280 --> 00:04:01,000
Speaker 1: don't know that the future humanity will have final answers,

70
00:04:01,080 --> 00:04:03,920
Speaker 1: but I think they will have unraveled more mysteries. They

71
00:04:03,920 --> 00:04:06,440
Speaker 1: will have deeper questions, at least than the ones that

72
00:04:06,480 --> 00:04:09,600
Speaker 1: we have. I see the long arc of science fans

73
00:04:09,680 --> 00:04:13,800
Speaker 1: towards being annoyingly right. It naps towards the truth. Yes,

74
00:04:16,000 --> 00:04:18,240
Speaker 1: but it is a wonderful universe full of amazing and

75
00:04:18,279 --> 00:04:21,680
Speaker 1: incredible things, things that seem unstoppable sometimes and things that

76
00:04:21,720 --> 00:04:25,160
Speaker 1: seem to travel across billions of light years to get

77
00:04:25,200 --> 00:04:27,360
Speaker 1: where they will always get to go. And it's a

78
00:04:27,440 --> 00:04:30,320
Speaker 1: universe filled with things that we want to understand. We

79
00:04:30,360 --> 00:04:32,680
Speaker 1: can't go out and visit all of these incredible things

80
00:04:32,680 --> 00:04:34,680
Speaker 1: in the universe I'm not going to take a trip

81
00:04:34,720 --> 00:04:37,279
Speaker 1: to orbited black hole. I'm not going to surf along

82
00:04:37,279 --> 00:04:39,919
Speaker 1: a gravitational wave. I'm not going to walk along the

83
00:04:39,960 --> 00:04:42,120
Speaker 1: surface of a neutron star. But we can still do

84
00:04:42,240 --> 00:04:46,120
Speaker 1: thought experiments. We can imagine what might happen in crazy

85
00:04:46,200 --> 00:04:48,599
Speaker 1: combinations of these events, what happens if you bank a

86
00:04:48,640 --> 00:04:51,000
Speaker 1: neutron star off another one and into a black hole.

87
00:04:51,160 --> 00:04:52,839
Speaker 1: These are fun games to play in your mind, and

88
00:04:52,880 --> 00:04:56,080
Speaker 1: they can also teach us things about the universe. Right,

89
00:04:56,160 --> 00:04:58,520
Speaker 1: and if you're deluded enough, the mind games are just

90
00:04:58,560 --> 00:05:01,360
Speaker 1: as good as the real thing. Right, Surfing a neutron

91
00:05:01,400 --> 00:05:03,960
Speaker 1: star in your head, is in your daydream, it could

92
00:05:04,000 --> 00:05:06,480
Speaker 1: be just as good as doing it well. As an experimentalist,

93
00:05:06,600 --> 00:05:10,440
Speaker 1: I have to say that actually collecting data as no substitute,

94
00:05:10,440 --> 00:05:13,359
Speaker 1: because the universe is filled with surprises, and often we

95
00:05:13,440 --> 00:05:15,880
Speaker 1: think we know what will happen in these situations, and

96
00:05:15,920 --> 00:05:18,720
Speaker 1: the universe says, oops, sorry, silly human, We're going with

97
00:05:18,800 --> 00:05:21,840
Speaker 1: secret options. C. But to prepare for those things, just

98
00:05:21,839 --> 00:05:25,080
Speaker 1: to sort of like test our understanding of concepts, we

99
00:05:25,080 --> 00:05:28,039
Speaker 1: could try to bring together crazy intense ideas that we

100
00:05:28,080 --> 00:05:30,360
Speaker 1: have in our minds and wondered like What would happen

101
00:05:30,560 --> 00:05:32,680
Speaker 1: if they bounced off each other? What would happen if

102
00:05:32,720 --> 00:05:35,320
Speaker 1: I sent a against b What would happen in these

103
00:05:35,400 --> 00:05:38,880
Speaker 1: various scenarios. It's like tests our understanding. Wait, is this

104
00:05:38,920 --> 00:05:42,640
Speaker 1: whole episode about the Hulk punching Superman? Are we actually

105
00:05:42,680 --> 00:05:46,360
Speaker 1: doing this? We're talking about the physics Hulk punching the

106
00:05:46,360 --> 00:05:49,599
Speaker 1: physics Superman. I thought you were going to say the

107
00:05:49,640 --> 00:05:52,160
Speaker 1: maths Superman. That would be a matchup for the ages.

108
00:05:52,880 --> 00:05:55,159
Speaker 1: But it's sort of similar. Like if you ask questions

109
00:05:55,160 --> 00:05:58,080
Speaker 1: about what happens when Hulk fight Superman, then it makes

110
00:05:58,080 --> 00:06:01,159
Speaker 1: you think carefully about those extremes you never imagined before,

111
00:06:01,160 --> 00:06:03,760
Speaker 1: like who really is stronger? Like how hard of a

112
00:06:03,800 --> 00:06:06,760
Speaker 1: punch can the Hulk really take? Does he have bones

113
00:06:06,800 --> 00:06:10,040
Speaker 1: that can get broken? I mean, is it really impossible

114
00:06:10,080 --> 00:06:13,040
Speaker 1: for Superman to break hulks bones? I think these are

115
00:06:13,040 --> 00:06:15,960
Speaker 1: deep questions that you know, the writers of that universe

116
00:06:16,040 --> 00:06:18,440
Speaker 1: then have to figure out in our universe. It makes

117
00:06:18,520 --> 00:06:21,480
Speaker 1: us wonder about the mathematics of extreme situations, and those

118
00:06:21,480 --> 00:06:24,359
Speaker 1: are places where we can really learn about the fundamental

119
00:06:24,440 --> 00:06:27,120
Speaker 1: nature these objects were tossing against each other. Yeah, because

120
00:06:27,120 --> 00:06:29,440
Speaker 1: I guess thinking about the extremes really kind of pushes

121
00:06:29,440 --> 00:06:31,640
Speaker 1: your thinking about these things and really kind of pushes

122
00:06:31,680 --> 00:06:34,560
Speaker 1: your theories to maybe the breaking point, right, because there

123
00:06:34,560 --> 00:06:37,080
Speaker 1: are some questions you can ask that maybe don't have

124
00:06:37,120 --> 00:06:40,280
Speaker 1: an answer exactly, and they can reveal inconsistencies. And we

125
00:06:40,360 --> 00:06:42,679
Speaker 1: hear our listeners doing this kind of stuff all the time.

126
00:06:42,720 --> 00:06:45,040
Speaker 1: You know, they're wondering about like what if I throw

127
00:06:45,080 --> 00:06:46,800
Speaker 1: this into a black hole? What if I throw that

128
00:06:46,880 --> 00:06:49,200
Speaker 1: into a black hole? What do I throw another black

129
00:06:49,200 --> 00:06:51,919
Speaker 1: hole into another black hole? Right? And these are the

130
00:06:51,960 --> 00:06:54,440
Speaker 1: games they're playing in their minds when they're just seeking

131
00:06:54,480 --> 00:06:57,400
Speaker 1: to understand what are the rules, and the way to

132
00:06:57,440 --> 00:06:59,280
Speaker 1: figure out what the rules are are to push them

133
00:06:59,360 --> 00:07:01,839
Speaker 1: are to break them. Every parent knows that's true. And

134
00:07:01,880 --> 00:07:04,160
Speaker 1: so today on the podcast, we'll be tackling the question

135
00:07:09,279 --> 00:07:14,120
Speaker 1: can a gravitational wave pass through a black hole? Now, Daniel,

136
00:07:14,160 --> 00:07:16,800
Speaker 1: I'm disappointed. I would have prefer the question to be

137
00:07:16,880 --> 00:07:20,640
Speaker 1: kind of gravitational wave punch a black hole? That might

138
00:07:20,680 --> 00:07:22,520
Speaker 1: get some more clicks. Well, I guess you can ask

139
00:07:22,520 --> 00:07:25,040
Speaker 1: the question is can a gravitational wave punch a black

140
00:07:25,080 --> 00:07:30,360
Speaker 1: hole without getting slurped in? Oh? Well, no, I want

141
00:07:30,360 --> 00:07:32,080
Speaker 1: to see him fight. I want to see him go

142
00:07:32,120 --> 00:07:34,000
Speaker 1: mono amount of for twenty minutes at the end of

143
00:07:34,000 --> 00:07:35,960
Speaker 1: the movie. But it is a question that's fun to

144
00:07:35,960 --> 00:07:40,560
Speaker 1: think about because black holes are famously impenetrables, can survive anything.

145
00:07:40,600 --> 00:07:42,960
Speaker 1: You can even throw another black hole into it, and

146
00:07:43,000 --> 00:07:46,000
Speaker 1: gravitational waves are sort of famous for being able to

147
00:07:46,040 --> 00:07:49,520
Speaker 1: pass through almost anything because they are ripples in space

148
00:07:49,560 --> 00:07:52,640
Speaker 1: and time itself. And so it's our version of Hulk

149
00:07:52,880 --> 00:07:56,080
Speaker 1: versus Superman. Yeah, it's almost like this that famous question

150
00:07:56,160 --> 00:07:59,800
Speaker 1: what happens when an unstoppable force meets an unmovable object.

151
00:08:00,040 --> 00:08:02,080
Speaker 1: This is one of these like questions that just go

152
00:08:02,160 --> 00:08:04,200
Speaker 1: to infinity sort of. Well, you know, in philosophy you

153
00:08:04,240 --> 00:08:05,880
Speaker 1: can make up any kind of thing you want and

154
00:08:05,920 --> 00:08:08,280
Speaker 1: pit it against something else, and you're making up the

155
00:08:08,360 --> 00:08:11,240
Speaker 1: rules also, so it doesn't matter. But here in our

156
00:08:11,360 --> 00:08:14,600
Speaker 1: universe we think there are real rules and experiments should

157
00:08:14,600 --> 00:08:17,640
Speaker 1: have outcomes, Like this is something which we think happens

158
00:08:17,800 --> 00:08:22,080
Speaker 1: in the universe. You know, gravitational waves do hit black holes,

159
00:08:22,120 --> 00:08:24,240
Speaker 1: and so there is an answer either they make it

160
00:08:24,280 --> 00:08:27,240
Speaker 1: out the other side or they get slurred in. And

161
00:08:27,280 --> 00:08:29,240
Speaker 1: so then the question is like, what do we think

162
00:08:29,440 --> 00:08:32,320
Speaker 1: is going to happen? Does our understanding of these things

163
00:08:32,440 --> 00:08:35,960
Speaker 1: allow us to predict the result, and then could we

164
00:08:36,000 --> 00:08:38,560
Speaker 1: eventually go out and measure it. Yeah, because actually this

165
00:08:38,600 --> 00:08:41,520
Speaker 1: thing is happening right like right now, all the time, probably, right.

166
00:08:41,600 --> 00:08:43,800
Speaker 1: I mean, there are you know, as far as we know,

167
00:08:43,960 --> 00:08:46,640
Speaker 1: you know, millions of black holes out there, probably, and

168
00:08:46,720 --> 00:08:49,680
Speaker 1: there are definitely gravitational waves going around all the time

169
00:08:49,920 --> 00:08:52,440
Speaker 1: all around this. You know, we are bathed in very

170
00:08:52,559 --> 00:08:56,760
Speaker 1: very gentle gravitational waves all the time. And so this

171
00:08:56,960 --> 00:08:59,920
Speaker 1: in principle should be happening constantly, So something we should

172
00:08:59,920 --> 00:09:02,360
Speaker 1: be you're out eventually. Yeah. And also kind of black

173
00:09:02,360 --> 00:09:06,600
Speaker 1: hole surf a gravitational wave or is that the next episode,

174
00:09:06,679 --> 00:09:09,880
Speaker 1: that's the sequel, that's black hole surfer. One of them

175
00:09:09,920 --> 00:09:12,720
Speaker 1: dies when they come back in the sequel. Well, as usual,

176
00:09:12,800 --> 00:09:14,760
Speaker 1: we were wondering how many people have thought about this

177
00:09:14,960 --> 00:09:18,320
Speaker 1: impossible or maybe incredible question of what happens when a

178
00:09:18,480 --> 00:09:21,040
Speaker 1: gravitational wave meets a black hole. And so as usual,

179
00:09:21,120 --> 00:09:23,160
Speaker 1: Daniel went out there to ask people on the internet.

180
00:09:23,200 --> 00:09:25,199
Speaker 1: And so if you'd like to hear questions that might

181
00:09:25,240 --> 00:09:28,319
Speaker 1: blow your mind or at least blow up your understanding

182
00:09:28,320 --> 00:09:30,959
Speaker 1: of physics, please they'll be shy, right, to meet two

183
00:09:31,080 --> 00:09:34,000
Speaker 1: questions at Daniel and Jorge dot com and we can

184
00:09:34,040 --> 00:09:37,240
Speaker 1: all enjoy hearing your answers on the podcast. Think about

185
00:09:37,280 --> 00:09:39,880
Speaker 1: it for a second. Do you think a gravitational wave

186
00:09:40,000 --> 00:09:43,040
Speaker 1: can pass through a black hole? Here's what people had

187
00:09:43,080 --> 00:09:46,439
Speaker 1: to say. I don't think so, because a black hole

188
00:09:46,440 --> 00:09:52,000
Speaker 1: can sucking pretty much anything, Okay, But a gravitational wave

189
00:09:53,040 --> 00:10:01,040
Speaker 1: is just the change in the curvature of space as

190
00:10:01,120 --> 00:10:07,040
Speaker 1: it propagates with distance from a source of gravity at

191
00:10:07,080 --> 00:10:10,040
Speaker 1: the speed of light. I guess they could pass around

192
00:10:10,679 --> 00:10:16,200
Speaker 1: a black hole. Yeah. Maybe. And no, and through a

193
00:10:16,280 --> 00:10:21,280
Speaker 1: black hole because you would be really the world's the

194
00:10:21,360 --> 00:10:27,120
Speaker 1: universe's trapdoor. Yeah, because the gravity that you are feeling

195
00:10:27,200 --> 00:10:31,800
Speaker 1: in a gravitational wave is based off the distance of

196
00:10:32,160 --> 00:10:35,800
Speaker 1: the yourself from that object. So if there was a

197
00:10:35,800 --> 00:10:38,880
Speaker 1: black hole in between, yeah, it shouldn't affect it at all.

198
00:10:39,440 --> 00:10:44,480
Speaker 1: I would say that gravitational waves do because there is

199
00:10:44,600 --> 00:10:48,920
Speaker 1: some form holding it all together. So I would say, um,

200
00:10:49,640 --> 00:10:57,480
Speaker 1: I mean assuming that um hawkings, radiation can split, particles

201
00:10:57,480 --> 00:11:00,880
Speaker 1: can split and into it. Yeah, maybe you can. I

202
00:11:00,880 --> 00:11:04,440
Speaker 1: don't know, prove me wrong. Yes, I believe gravitational waves

203
00:11:04,480 --> 00:11:08,400
Speaker 1: would pass through a black hole. More specifically, I think

204
00:11:08,440 --> 00:11:10,520
Speaker 1: they would pass around a black hole. I think a

205
00:11:10,559 --> 00:11:15,080
Speaker 1: black hole would fundamentally change the gravitational wave in the

206
00:11:15,120 --> 00:11:17,560
Speaker 1: same way that an object would change a radar signal.

207
00:11:18,320 --> 00:11:21,560
Speaker 1: Maybe the gravitational wave would be able to give us

208
00:11:21,600 --> 00:11:25,959
Speaker 1: an intimate look at the structure, shape, the other factors

209
00:11:25,960 --> 00:11:28,439
Speaker 1: that we are unaware of. Of a black hole. I'm

210
00:11:28,440 --> 00:11:34,120
Speaker 1: not sure, because well, a black hole is as an

211
00:11:34,120 --> 00:11:39,439
Speaker 1: infinite gravity and I'm not sure if they can pass

212
00:11:39,480 --> 00:11:42,640
Speaker 1: through a black hole. I think they would be sucked in.

213
00:11:43,880 --> 00:11:45,880
Speaker 1: That would be my answer for that question. Now I

214
00:11:45,920 --> 00:11:49,600
Speaker 1: want to say, no, they can't, because surely nothing can

215
00:11:49,640 --> 00:11:51,760
Speaker 1: pass through a black hole, nothing can go through the

216
00:11:51,800 --> 00:11:55,200
Speaker 1: event horizon and through the singularity and then come out

217
00:11:55,240 --> 00:11:59,560
Speaker 1: the other end back into space. So no, no, I'm

218
00:11:59,600 --> 00:12:01,840
Speaker 1: going to say, know they can't do Surely they would

219
00:12:01,880 --> 00:12:06,840
Speaker 1: be swallowed up within the black hole. Um and you know,

220
00:12:06,920 --> 00:12:10,000
Speaker 1: kind of due to the massive curvature of space itself,

221
00:12:10,559 --> 00:12:14,240
Speaker 1: and gravitational waves are you know, kind of integrated with

222
00:12:14,360 --> 00:12:17,240
Speaker 1: very fabric of space. Then they would be directed only

223
00:12:17,280 --> 00:12:20,680
Speaker 1: in one direction light light is and all information that

224
00:12:20,840 --> 00:12:24,640
Speaker 1: is to the singularity. So no, gravitational waves can't pass

225
00:12:24,679 --> 00:12:28,400
Speaker 1: through a black hole. I believe gravitational waves can pass

226
00:12:28,480 --> 00:12:32,040
Speaker 1: through black holes, although I'm convinced the day will be

227
00:12:32,120 --> 00:12:36,920
Speaker 1: distarted as they go through. They will also started the

228
00:12:37,240 --> 00:12:40,840
Speaker 1: black hole while they are passing through, because gravitational waves

229
00:12:41,160 --> 00:12:45,480
Speaker 1: start space and time, and the black hole is part

230
00:12:45,520 --> 00:12:49,199
Speaker 1: of the space and time although almost itches on universe,

231
00:12:50,120 --> 00:12:53,800
Speaker 1: but the group gravitational waves will also be started by

232
00:12:53,920 --> 00:12:58,800
Speaker 1: their black hole. Black holes attract each other, so I

233
00:12:58,880 --> 00:13:05,200
Speaker 1: guess not fostival gravitational waves. They are this rebels in

234
00:13:05,679 --> 00:13:12,359
Speaker 1: space and time fabric and also a black hole distorts

235
00:13:12,840 --> 00:13:19,120
Speaker 1: space and time, and when these two interact, most likely

236
00:13:20,559 --> 00:13:26,880
Speaker 1: these waves won't get to affect the object, the black

237
00:13:26,920 --> 00:13:30,280
Speaker 1: hole itself, it's core. I don't know if gravitational waves

238
00:13:30,320 --> 00:13:32,920
Speaker 1: will pass through a black hole, but I do think

239
00:13:33,200 --> 00:13:36,960
Speaker 1: that they do because we are able to know where

240
00:13:37,000 --> 00:13:39,679
Speaker 1: there are black holes and when they shock with one

241
00:13:39,679 --> 00:13:42,600
Speaker 1: another because of the gravitational waves. So I'm guessing that

242
00:13:42,640 --> 00:13:44,920
Speaker 1: they do pass through it. They don't go inside it,

243
00:13:45,840 --> 00:13:49,360
Speaker 1: but they go around it. Yes, I think any part

244
00:13:49,360 --> 00:13:52,240
Speaker 1: of the wave that interacts with the event horizon is

245
00:13:52,240 --> 00:13:56,560
Speaker 1: going to get trapped inside because all all directions point

246
00:13:56,559 --> 00:13:59,640
Speaker 1: towards the singularity. Once you're inside the event horizon, but

247
00:13:59,679 --> 00:14:02,760
Speaker 1: I think any waves outside of that might get bent

248
00:14:02,840 --> 00:14:05,199
Speaker 1: around the black hole around the event horizon and actually

249
00:14:05,200 --> 00:14:09,640
Speaker 1: get like gravitationally focused, like gravitational lensing. All right, it

250
00:14:09,679 --> 00:14:12,120
Speaker 1: seems like people are cheering for Superman here in this

251
00:14:12,160 --> 00:14:15,040
Speaker 1: case for the black hole. No, many things the hole

252
00:14:15,080 --> 00:14:16,839
Speaker 1: will survive. No, there's some people that that's say it

253
00:14:16,880 --> 00:14:19,240
Speaker 1: will pass through it or at least around it. You know,

254
00:14:19,320 --> 00:14:22,160
Speaker 1: in the end, these things are both curvatures in space,

255
00:14:22,560 --> 00:14:24,760
Speaker 1: so it's tricky stuff to think about. All right, Well,

256
00:14:24,800 --> 00:14:27,840
Speaker 1: let's jump in and let's tackle one of these combatants

257
00:14:27,840 --> 00:14:31,120
Speaker 1: one at a time, and let's start with the black hole. Daniel,

258
00:14:31,160 --> 00:14:32,960
Speaker 1: what's a good way to define a black hole? So

259
00:14:33,000 --> 00:14:35,240
Speaker 1: you might think of a black hole something really weird,

260
00:14:35,520 --> 00:14:39,040
Speaker 1: very strange in our universe, something that's hard to grapple with.

261
00:14:39,080 --> 00:14:40,920
Speaker 1: But what a black hole looks like depends a lot

262
00:14:40,960 --> 00:14:43,320
Speaker 1: on sort of how close you are to it, and

263
00:14:43,440 --> 00:14:46,640
Speaker 1: from far away, a black hole just looks like anything

264
00:14:46,680 --> 00:14:50,200
Speaker 1: else that has mass. Right, black hole is a massive

265
00:14:50,280 --> 00:14:54,080
Speaker 1: object in space, which means that it bends space, and

266
00:14:54,120 --> 00:14:57,760
Speaker 1: so that curved space then causes gravity. So you can

267
00:14:57,800 --> 00:14:59,800
Speaker 1: be in an orbit around a black hole the same

268
00:14:59,800 --> 00:15:01,760
Speaker 1: way you can be in the orbit around the Sun

269
00:15:02,000 --> 00:15:05,440
Speaker 1: or an orbit around the Earth. Are away from any object,

270
00:15:05,520 --> 00:15:08,720
Speaker 1: its gravity is the same as like a point particle

271
00:15:08,960 --> 00:15:10,920
Speaker 1: placed at the center of mass, And that's true for

272
00:15:10,960 --> 00:15:13,160
Speaker 1: a black hole, or for the Sun, or for any

273
00:15:13,240 --> 00:15:17,000
Speaker 1: weird like huge unicorn shaped rock for example, and so

274
00:15:17,040 --> 00:15:19,240
Speaker 1: far away from a black hole, there's no difference. The

275
00:15:19,320 --> 00:15:22,200
Speaker 1: difference is that a black hole is very very dense.

276
00:15:22,560 --> 00:15:24,280
Speaker 1: So now take all the mass that's in the Sun,

277
00:15:24,320 --> 00:15:28,240
Speaker 1: for example, compacted down to a very very small space.

278
00:15:28,920 --> 00:15:32,040
Speaker 1: Now you can get much closer to the center of

279
00:15:32,120 --> 00:15:34,240
Speaker 1: mass than you could before. When it comes to the Sun,

280
00:15:34,280 --> 00:15:36,000
Speaker 1: you're gonna get to the surface of the Sun. Right

281
00:15:36,000 --> 00:15:38,440
Speaker 1: If you dig into the Sun, then the gravity from

282
00:15:38,440 --> 00:15:41,280
Speaker 1: the Sun actually starts to decrease. But with a black hole,

283
00:15:41,600 --> 00:15:44,640
Speaker 1: you can get closer and closer and closer to that

284
00:15:44,720 --> 00:15:48,080
Speaker 1: point mass, because general relativity tells us that that's exactly

285
00:15:48,080 --> 00:15:50,840
Speaker 1: what's They're a point mass, but all of that stuff

286
00:15:50,960 --> 00:15:54,560
Speaker 1: wrapped into a tiny little volume, So the gravitational curvature

287
00:15:54,600 --> 00:15:58,640
Speaker 1: becomes really really strong, so powerful that there's an event

288
00:15:58,680 --> 00:16:02,480
Speaker 1: horizon beyond which nothing can escape, no information can leak

289
00:16:02,520 --> 00:16:05,480
Speaker 1: out past the event horizon. Right, That's something that I

290
00:16:05,480 --> 00:16:07,400
Speaker 1: think is kind of interesting about black holes. It's that,

291
00:16:07,520 --> 00:16:10,000
Speaker 1: as you said, it's just a lot of mass compacted

292
00:16:10,080 --> 00:16:12,880
Speaker 1: really tightly. And it's not like as you're squeezing this

293
00:16:13,000 --> 00:16:15,920
Speaker 1: mass and suddenly something explodes or something pops or a

294
00:16:15,960 --> 00:16:18,160
Speaker 1: hole is punched through the based up of the universe.

295
00:16:18,160 --> 00:16:21,240
Speaker 1: It's almost like a gradual process. There's nothing exciting happens

296
00:16:21,280 --> 00:16:23,360
Speaker 1: as you squeeze down this mass. Yeah, that's a really

297
00:16:23,360 --> 00:16:26,760
Speaker 1: interesting question to imagine, Like taking a star and compacting

298
00:16:26,840 --> 00:16:31,000
Speaker 1: it down gradually, when does the black hole actually form?

299
00:16:31,240 --> 00:16:34,200
Speaker 1: And so a black hole is defined by the presence

300
00:16:34,280 --> 00:16:38,640
Speaker 1: of the event horizon, this region past which you cannot escape.

301
00:16:38,640 --> 00:16:40,880
Speaker 1: I remember the event horizon. It's not like, you know,

302
00:16:40,880 --> 00:16:44,200
Speaker 1: there's no flashing lights or firewalls or anything crazy there.

303
00:16:44,280 --> 00:16:46,560
Speaker 1: It's just sort of like a location. It's a distance

304
00:16:46,880 --> 00:16:51,120
Speaker 1: from this center of mass beyond which every future ends

305
00:16:51,240 --> 00:16:53,320
Speaker 1: up at the center. And you know, to actually know

306
00:16:53,360 --> 00:16:55,120
Speaker 1: where the event horizon is, you have to know the

307
00:16:55,120 --> 00:16:59,640
Speaker 1: whole future history of this object. It's the place pass

308
00:16:59,680 --> 00:17:02,800
Speaker 1: which no test particles ever escapes. You have to know

309
00:17:02,840 --> 00:17:05,240
Speaker 1: sort of like the future history of every test particle

310
00:17:05,320 --> 00:17:07,320
Speaker 1: you shoot at this thing to know where the event

311
00:17:07,320 --> 00:17:09,960
Speaker 1: horizon actually is. But we can calculate it. We can

312
00:17:09,960 --> 00:17:13,520
Speaker 1: say if you have a certain mass within a certain radius,

313
00:17:13,760 --> 00:17:16,800
Speaker 1: then you get an event horizon. So now take the

314
00:17:16,880 --> 00:17:20,560
Speaker 1: Sun and start squeezing it down smaller and smaller and smaller.

315
00:17:20,760 --> 00:17:23,120
Speaker 1: At some point it's going to pass that threshold where

316
00:17:23,119 --> 00:17:25,240
Speaker 1: you have enough mass within a radius, and then you

317
00:17:25,280 --> 00:17:28,040
Speaker 1: get that event horizon. Right, Like, as I'm squeezing the Sun,

318
00:17:28,320 --> 00:17:30,760
Speaker 1: it's gonna look like a sun that's just getting smaller

319
00:17:30,760 --> 00:17:33,480
Speaker 1: and smaller and smaller, maybe brighter, but then at some

320
00:17:33,520 --> 00:17:36,040
Speaker 1: point it's just gonna blink turn black. Right, It's not

321
00:17:36,119 --> 00:17:38,280
Speaker 1: like it's going to send out shock ways or the

322
00:17:38,359 --> 00:17:41,280
Speaker 1: universe is gonna shake. It'll just like blink turn black. Yeah,

323
00:17:41,320 --> 00:17:44,840
Speaker 1: And actually it's gonna gradually fade to black because as

324
00:17:44,880 --> 00:17:47,960
Speaker 1: it gets more and more gravitational curvature, the light that's

325
00:17:48,000 --> 00:17:50,000
Speaker 1: coming off of that Sun is going to get more

326
00:17:50,000 --> 00:17:53,119
Speaker 1: and more gravitationally red shifted. So if you squeeze this

327
00:17:53,200 --> 00:17:55,359
Speaker 1: object down, it gets redder and redder and redder and

328
00:17:55,400 --> 00:17:58,000
Speaker 1: eventually black. So it's a gradual process. It's no like

329
00:17:58,040 --> 00:18:02,280
Speaker 1: crazy fireworks, just thing Yeah, pretty cool. And the other

330
00:18:02,320 --> 00:18:05,080
Speaker 1: thing about black holes is that they're hungry. They can

331
00:18:05,200 --> 00:18:08,680
Speaker 1: anything you throw into them into this event horizon supposedly

332
00:18:08,880 --> 00:18:11,320
Speaker 1: can never come out. Yeah, it's the most fascinating aspect

333
00:18:11,440 --> 00:18:14,960
Speaker 1: of these black holes that they eat anything. Right, Anything

334
00:18:15,000 --> 00:18:18,760
Speaker 1: with energy that enters the black hole just grows its

335
00:18:18,920 --> 00:18:22,520
Speaker 1: energy just makes it stronger. Right, So people ask me, like,

336
00:18:22,600 --> 00:18:24,800
Speaker 1: what happens to me throw a nuclear weapon into a

337
00:18:24,840 --> 00:18:27,000
Speaker 1: black hole? As if a black hole is like some

338
00:18:27,119 --> 00:18:30,199
Speaker 1: structure that you could explode if you like push on

339
00:18:30,280 --> 00:18:32,919
Speaker 1: it internally with enough force, and if you let this

340
00:18:33,000 --> 00:18:35,760
Speaker 1: nuclear bomb go inside and then blow up, you can

341
00:18:35,840 --> 00:18:38,959
Speaker 1: somehow explode the event horizon from the inside. Remember, the

342
00:18:38,960 --> 00:18:42,280
Speaker 1: event horizon is just there because of the strength of gravity.

343
00:18:42,640 --> 00:18:46,399
Speaker 1: And as you add more energy, even an exploding nuclear bomb,

344
00:18:46,720 --> 00:18:51,840
Speaker 1: you are just curving space more, which makes it stronger gravitationally. Right.

345
00:18:51,880 --> 00:18:54,200
Speaker 1: So there's nothing you can do to a black hole

346
00:18:54,240 --> 00:18:57,359
Speaker 1: to weaken it. Anything you do that adds energy makes

347
00:18:57,440 --> 00:19:00,399
Speaker 1: it stronger. Right. And we talked about last time happens

348
00:19:00,440 --> 00:19:02,080
Speaker 1: even if you put in a white hole into a

349
00:19:02,119 --> 00:19:04,960
Speaker 1: black hole, right, the black hole sort of wins. Yeah,

350
00:19:05,000 --> 00:19:07,600
Speaker 1: we don't know that white holes are real, but theoretically

351
00:19:07,880 --> 00:19:10,800
Speaker 1: a black hole will turn that white hole into another

352
00:19:10,840 --> 00:19:12,920
Speaker 1: black hole and then gobble it and you get some

353
00:19:13,160 --> 00:19:16,119
Speaker 1: big black hole. And we talked on the program recently

354
00:19:16,160 --> 00:19:19,400
Speaker 1: also about exactly what happens when two black holes merge,

355
00:19:19,440 --> 00:19:22,280
Speaker 1: how their event horizons come together. You get for a

356
00:19:22,280 --> 00:19:25,639
Speaker 1: moment this weird peanut shaped event horizon, and then it

357
00:19:25,640 --> 00:19:29,240
Speaker 1: turns into a new larger black hole with a spherical

358
00:19:29,280 --> 00:19:32,200
Speaker 1: event horizon. But it's super fascinating. Another thing that people

359
00:19:32,200 --> 00:19:35,320
Speaker 1: ask about in terms of like growing black holes is

360
00:19:35,400 --> 00:19:37,560
Speaker 1: how you actually see it happen. Like if you throw

361
00:19:37,560 --> 00:19:39,919
Speaker 1: a banana into a black hole, it's sort of like

362
00:19:40,000 --> 00:19:43,600
Speaker 1: falls towards the black hole, but then time slows down

363
00:19:43,760 --> 00:19:47,800
Speaker 1: because there's gravitational time dilation near the surface, so you

364
00:19:47,840 --> 00:19:51,119
Speaker 1: never actually see the banana fall into the black hole.

365
00:19:51,200 --> 00:19:53,320
Speaker 1: And people wonder about, like, well, how do we actually

366
00:19:53,320 --> 00:19:56,800
Speaker 1: see black holes growing if things freeze before they fall

367
00:19:56,840 --> 00:19:59,000
Speaker 1: into them. And so the answer is to think again

368
00:19:59,040 --> 00:20:02,480
Speaker 1: about the gravity national energy of the black hole. Right

369
00:20:02,520 --> 00:20:05,000
Speaker 1: as you throw this banana into the black hole, it's

370
00:20:05,000 --> 00:20:07,760
Speaker 1: not like it needs to pass the event horizons some

371
00:20:08,000 --> 00:20:11,280
Speaker 1: magical marker before the black hole officially has eaten it,

372
00:20:11,440 --> 00:20:12,800
Speaker 1: you know, the banana in the black hole, and they

373
00:20:12,800 --> 00:20:15,679
Speaker 1: are now part of a larger gravitational system. So the

374
00:20:15,720 --> 00:20:19,000
Speaker 1: banana is contributing to the gravitational energy of the black

375
00:20:19,040 --> 00:20:22,680
Speaker 1: hole before it crosses the event horizon. Another way to

376
00:20:22,720 --> 00:20:24,920
Speaker 1: think about that is that the event horizon is growing

377
00:20:25,000 --> 00:20:27,800
Speaker 1: outwards to meet the banana. They never actually meet. You

378
00:20:27,800 --> 00:20:30,520
Speaker 1: have to wait till time equals infinity for them to meet.

379
00:20:30,840 --> 00:20:33,560
Speaker 1: But this event horizon is getting pulled out by the

380
00:20:33,600 --> 00:20:36,800
Speaker 1: banana's mass, so they never actually cross. And if the

381
00:20:36,800 --> 00:20:39,320
Speaker 1: banana is the last thing anybody ever threw into this

382
00:20:39,400 --> 00:20:42,240
Speaker 1: black hole, you're right, it wouldn't actually fall in. But

383
00:20:42,280 --> 00:20:44,440
Speaker 1: then if somebody else comes along and through the donut

384
00:20:44,640 --> 00:20:48,200
Speaker 1: towards the black hole, that donut pulls the event horizon

385
00:20:48,240 --> 00:20:51,280
Speaker 1: out also pass the banana, So now the banana has

386
00:20:51,320 --> 00:20:54,280
Speaker 1: fallen in. So the last thing anybody ever throws into

387
00:20:54,280 --> 00:20:57,480
Speaker 1: a black hole never actually falls in, but everything else

388
00:20:57,520 --> 00:20:59,960
Speaker 1: that was thrown in before does pass the event horriz.

389
00:21:00,359 --> 00:21:02,359
Speaker 1: So that's a useful way to think about, like how

390
00:21:02,400 --> 00:21:04,800
Speaker 1: the energy of the black hole is growing, right, It's

391
00:21:04,800 --> 00:21:07,680
Speaker 1: almost like the black hole grows and eats the banana,

392
00:21:07,840 --> 00:21:11,480
Speaker 1: which is always a good idea banana. I mean, it

393
00:21:11,520 --> 00:21:13,760
Speaker 1: doesn't have any choice, right. The black holes just eats

394
00:21:13,760 --> 00:21:15,880
Speaker 1: whatever you throw at it. It might not like bananas,

395
00:21:16,000 --> 00:21:18,200
Speaker 1: might be really grumpy that somebody keeps the ring bananas

396
00:21:18,200 --> 00:21:20,520
Speaker 1: in there. But it's got no options. I guess it's not.

397
00:21:20,560 --> 00:21:23,359
Speaker 1: It's not going to let it slide. Well, what about

398
00:21:23,359 --> 00:21:25,840
Speaker 1: the idea that you know, sometimes black holes might be

399
00:21:26,280 --> 00:21:29,600
Speaker 1: connected through a warm hole to a white hole, right,

400
00:21:29,680 --> 00:21:33,359
Speaker 1: which would be spewing out energy instead of sucking in energy,

401
00:21:33,480 --> 00:21:36,080
Speaker 1: and that energy is coming from the black holes. Is

402
00:21:36,119 --> 00:21:38,600
Speaker 1: it's possible for a black hole to kind of leak

403
00:21:38,680 --> 00:21:41,520
Speaker 1: out or or you know, shrink because it's leaking through

404
00:21:41,560 --> 00:21:43,600
Speaker 1: a white hole somewhere else. Yeah, there are ways that

405
00:21:43,680 --> 00:21:45,800
Speaker 1: black holes can shrink. One of them that sounds sort

406
00:21:45,800 --> 00:21:48,399
Speaker 1: of stronger. Theoretical footing that we've never seen it before

407
00:21:48,800 --> 00:21:51,280
Speaker 1: is Hawking radiation. You know, the quantum effects near the

408
00:21:51,359 --> 00:21:53,120
Speaker 1: edge of the black hole, and the black hole having

409
00:21:53,119 --> 00:21:56,359
Speaker 1: a non zero temperature suggests that it should be radiating

410
00:21:56,400 --> 00:21:59,359
Speaker 1: away energy, which shrinks the mass of the black hole.

411
00:21:59,600 --> 00:22:01,879
Speaker 1: So the concept there again is the size of the

412
00:22:01,880 --> 00:22:04,520
Speaker 1: black hole. The radius the event horizon depends on the

413
00:22:04,560 --> 00:22:07,280
Speaker 1: total energy there. So if you take away energy, the

414
00:22:07,320 --> 00:22:10,800
Speaker 1: black hole shrinks. And another option, though even on much

415
00:22:10,840 --> 00:22:14,639
Speaker 1: worse footing theoretically, is this question of white holes. It

416
00:22:14,800 --> 00:22:17,399
Speaker 1: is possible that black holes and white holes sort of

417
00:22:17,440 --> 00:22:20,720
Speaker 1: share a singularity that connected by a wormhole. But this

418
00:22:20,800 --> 00:22:24,560
Speaker 1: is like speculation upon speculation, But yes, absolutely, mask could

419
00:22:24,560 --> 00:22:27,080
Speaker 1: then move through that wormhole, come out the other side

420
00:22:27,080 --> 00:22:29,320
Speaker 1: of the white hole, and shrink the size of that

421
00:22:29,359 --> 00:22:31,159
Speaker 1: black hole. And what would happen to the banana that

422
00:22:31,280 --> 00:22:33,560
Speaker 1: was at the border they got absorbed? Would it have

423
00:22:33,640 --> 00:22:35,480
Speaker 1: it then have a chance to escape the black hole

424
00:22:35,600 --> 00:22:38,720
Speaker 1: once it's inside the event horizon. I think the only

425
00:22:38,760 --> 00:22:40,560
Speaker 1: way for it to get out would be through the

426
00:22:40,600 --> 00:22:43,159
Speaker 1: wormhole and out the white hole. But what if the

427
00:22:43,760 --> 00:22:46,880
Speaker 1: you know, event horizon shrinks, I guess the banana would

428
00:22:47,080 --> 00:22:49,840
Speaker 1: fall in a little bit too, right, exactly, Yeah, banana

429
00:22:49,880 --> 00:22:51,480
Speaker 1: would fall in with it. So the moral of the

430
00:22:51,480 --> 00:22:53,640
Speaker 1: story is, if you drop your banana into a black hole,

431
00:22:53,720 --> 00:22:57,240
Speaker 1: let it go, because man, it's gone. Well, you can

432
00:22:57,280 --> 00:22:59,600
Speaker 1: go to the nearest white hole and maybe he'll come

433
00:22:59,600 --> 00:23:04,000
Speaker 1: out one particle at a time or something. That's right,

434
00:23:04,040 --> 00:23:05,720
Speaker 1: Go near your white hole and open your mouth and

435
00:23:05,760 --> 00:23:10,080
Speaker 1: see if it tastes like banana or donuts if you're lucky,

436
00:23:10,200 --> 00:23:13,280
Speaker 1: maybe banana donuts. There you go, it's the ultimate smoothie maker.

437
00:23:13,320 --> 00:23:15,240
Speaker 1: Just throw all of your ingredients into the black hole

438
00:23:15,320 --> 00:23:16,879
Speaker 1: and go stand by the white hole and see what

439
00:23:16,920 --> 00:23:20,040
Speaker 1: comes out. No, Danny, what happens if I take a

440
00:23:20,080 --> 00:23:21,919
Speaker 1: banana and put it through a donut? I think you

441
00:23:22,040 --> 00:23:27,680
Speaker 1: just invented the latest pop food craze. A bonut A BANONU.

442
00:23:28,440 --> 00:23:30,560
Speaker 1: All right, Well, that's a black hole. It's full of

443
00:23:30,680 --> 00:23:34,840
Speaker 1: interesting mysteries and amazing effects and physics that that are

444
00:23:34,880 --> 00:23:37,280
Speaker 1: going on and that we are starting to understand. But

445
00:23:37,320 --> 00:23:40,840
Speaker 1: then there's another fundamental and monumental thing in the universe

446
00:23:40,880 --> 00:23:44,000
Speaker 1: called a gravitational wave, and so let's get into what

447
00:23:44,160 --> 00:23:46,120
Speaker 1: that is and what's going to happen when the two

448
00:23:46,200 --> 00:23:49,320
Speaker 1: meet at the same place. But first let's take a

449
00:23:49,359 --> 00:24:04,800
Speaker 1: quick break. All right, we're talking about fun fan fiction.

450
00:24:04,840 --> 00:24:10,199
Speaker 1: I guess you know we're where conjuring imaginary meetups in

451
00:24:10,240 --> 00:24:14,520
Speaker 1: the universe physics fan fiction exactly, it's not quite fan fiction,

452
00:24:14,560 --> 00:24:17,480
Speaker 1: because this thing is happening, this question is happening all

453
00:24:17,480 --> 00:24:20,840
Speaker 1: over the universe. Probably gravitational waves are passing through all

454
00:24:20,880 --> 00:24:23,240
Speaker 1: of space and time and there are black holes in

455
00:24:23,280 --> 00:24:26,520
Speaker 1: the universe. So somewhere out there right now, there's probably

456
00:24:26,520 --> 00:24:30,399
Speaker 1: a gravitational wave hitting a black hole, almost certainly, and

457
00:24:30,440 --> 00:24:33,919
Speaker 1: the universe has to decide what happens. Right. That's the

458
00:24:33,960 --> 00:24:36,720
Speaker 1: amazing thing about experiments. You set something up in the

459
00:24:36,800 --> 00:24:38,879
Speaker 1: universe has to have an outcome. It can't be like,

460
00:24:39,240 --> 00:24:43,080
Speaker 1: I don't know, you figure it out, right. An answer

461
00:24:43,119 --> 00:24:46,920
Speaker 1: to experiments, the universe can't pass the buck exactly, can't

462
00:24:46,920 --> 00:24:50,040
Speaker 1: go pass I'm not sure about this one. They wrote

463
00:24:50,040 --> 00:24:51,679
Speaker 1: this cells into a corner and now they've got to

464
00:24:51,680 --> 00:24:54,480
Speaker 1: figure out how the movie ends, right exactly. Maybe that's

465
00:24:54,480 --> 00:24:56,720
Speaker 1: when the universe events time travel so we can red

466
00:24:56,720 --> 00:25:01,320
Speaker 1: con its own history. Yeah, Or maybe that's when it

467
00:25:01,359 --> 00:25:03,800
Speaker 1: invents event horizon so you can never know what's going on.

468
00:25:05,000 --> 00:25:07,040
Speaker 1: Maybe that's just the plot hole fixer for the universe.

469
00:25:07,200 --> 00:25:11,239
Speaker 1: It is the ultimate plot holes. Nice, but you know,

470
00:25:11,280 --> 00:25:14,720
Speaker 1: it's sort of an interesting statement in philosophy, this assumption

471
00:25:14,800 --> 00:25:18,000
Speaker 1: that the universe is in the end following laws, that

472
00:25:18,119 --> 00:25:21,000
Speaker 1: the laws aren't predictable, that we can figure them out,

473
00:25:21,240 --> 00:25:23,879
Speaker 1: and that the universe is bound by them. Right, That

474
00:25:23,960 --> 00:25:27,480
Speaker 1: every physical effect has a physical cause, and that means

475
00:25:27,560 --> 00:25:30,960
Speaker 1: that any physical situation you set up must be predictable

476
00:25:31,040 --> 00:25:34,720
Speaker 1: by those physical laws, and so something's got to happen, right,

477
00:25:34,920 --> 00:25:37,960
Speaker 1: Something's got to happen. Is that the mantra for physics,

478
00:25:38,280 --> 00:25:40,960
Speaker 1: Something's got to happen. What happens if I collide a

479
00:25:41,240 --> 00:25:44,800
Speaker 1: basilian particles together? Something's going to happen. Yeah. In physics

480
00:25:44,800 --> 00:25:46,960
Speaker 1: it goes by the name of unitarity. It says that

481
00:25:47,040 --> 00:25:49,400
Speaker 1: the wave function when you integrate it has to be one,

482
00:25:49,480 --> 00:25:52,920
Speaker 1: which means something's got to happen. The probability distribution has

483
00:25:52,960 --> 00:25:55,160
Speaker 1: to go somewhere. It can't be like you do this

484
00:25:55,280 --> 00:25:59,040
Speaker 1: experiment and nothing happens, or the particles just disappear. Right,

485
00:25:59,400 --> 00:26:02,920
Speaker 1: Quantum in nation flows through the universe. It can't be deleted,

486
00:26:03,000 --> 00:26:05,200
Speaker 1: which means that it's got to go somewhere. That's the

487
00:26:05,200 --> 00:26:07,040
Speaker 1: theory at least, Or do you think that's what's going

488
00:26:07,080 --> 00:26:08,800
Speaker 1: to happen or it has to happen, right. It could

489
00:26:08,840 --> 00:26:11,359
Speaker 1: be then maybe there are places where things break down. Right.

490
00:26:11,480 --> 00:26:14,800
Speaker 1: Certainly could be. We definitely don't understand quantum mechanics that deeply,

491
00:26:14,840 --> 00:26:17,960
Speaker 1: and we could also be philosophically wrong about the universe's

492
00:26:18,000 --> 00:26:21,280
Speaker 1: assumption that every experiment has an outcome that makes sense

493
00:26:21,320 --> 00:26:23,800
Speaker 1: and is reproducible. You know, that's just an assumption. It's

494
00:26:23,800 --> 00:26:26,200
Speaker 1: been working really well so far, but we don't really

495
00:26:26,240 --> 00:26:29,200
Speaker 1: know why even that is. So. Yeah, if you want

496
00:26:29,200 --> 00:26:31,639
Speaker 1: to question the foundations, then we can go all the

497
00:26:31,640 --> 00:26:33,520
Speaker 1: way down. Yeah. I mean, we used to think that

498
00:26:33,640 --> 00:26:36,600
Speaker 1: energy is always conserved, but it turns out then energy

499
00:26:36,680 --> 00:26:39,640
Speaker 1: is not always conserved in the whole universe. Yeah, exactly.

500
00:26:39,680 --> 00:26:42,320
Speaker 1: Physics has been upending the apple card for hundreds of years.

501
00:26:42,480 --> 00:26:44,960
Speaker 1: Al Right, Well, we talked about black holes for a while,

502
00:26:45,080 --> 00:26:47,320
Speaker 1: and now the question is what happens when it HiT's

503
00:26:47,320 --> 00:26:50,800
Speaker 1: a gravitational wave, which is something that's pretty cool. So

504
00:26:50,920 --> 00:26:52,960
Speaker 1: let's step through it and talk about what is a

505
00:26:53,000 --> 00:26:55,920
Speaker 1: gravitational wave. A gravitational wave is a combination of something

506
00:26:55,960 --> 00:26:59,919
Speaker 1: that's very familiar to us, a wave, an update in information,

507
00:27:00,400 --> 00:27:03,360
Speaker 1: and something that's very weird, right, which is gravity. So

508
00:27:03,680 --> 00:27:05,959
Speaker 1: you can think about gravitational waves. It's sort of like

509
00:27:06,040 --> 00:27:10,280
Speaker 1: a way to communicate gravitational information. You know, like you

510
00:27:10,320 --> 00:27:13,560
Speaker 1: are in space and there's gravity around you, there's a

511
00:27:13,600 --> 00:27:17,400
Speaker 1: gravitational field around you. Imagine for a moment that that's

512
00:27:17,440 --> 00:27:20,200
Speaker 1: not changing. It's the same you know, whatever is creating

513
00:27:20,240 --> 00:27:23,280
Speaker 1: that gravitational field is fixed in place and not changing,

514
00:27:23,680 --> 00:27:26,920
Speaker 1: So there's no gravitational information, there's no updates. Right, every

515
00:27:26,960 --> 00:27:29,840
Speaker 1: moment your gravitational force is the same. But what if

516
00:27:29,840 --> 00:27:33,120
Speaker 1: that does change. What if somebody, for example, deletes the Sun,

517
00:27:33,240 --> 00:27:35,480
Speaker 1: which is the source of your gravity, then how does

518
00:27:35,480 --> 00:27:38,760
Speaker 1: that information propagate through the universe. Newton said that it

519
00:27:38,840 --> 00:27:41,680
Speaker 1: was instantaneous, that if you deleted the Sun, gravity far

520
00:27:41,720 --> 00:27:44,080
Speaker 1: away from the Sun would instantly change, right, it would

521
00:27:44,080 --> 00:27:47,760
Speaker 1: go to zero instantly. Einstein told us that that's not true.

522
00:27:47,800 --> 00:27:52,240
Speaker 1: That gravitational information is information and the gravitational field takes

523
00:27:52,320 --> 00:27:55,520
Speaker 1: time to update, and that update the change in the

524
00:27:55,520 --> 00:27:59,720
Speaker 1: gravitational field propagating through space because the source of the

525
00:27:59,760 --> 00:28:03,400
Speaker 1: gravi potational field has changed. That is a gravitational wave.

526
00:28:03,520 --> 00:28:06,800
Speaker 1: It's an update to the gravitational field. Right. It's kind

527
00:28:06,800 --> 00:28:08,639
Speaker 1: of like if you ask, like what happens if someone

528
00:28:08,800 --> 00:28:11,800
Speaker 1: shakes the sun or the sun like wiggles, Like do

529
00:28:11,840 --> 00:28:14,240
Speaker 1: you feel those wiggles right away or do you have

530
00:28:14,280 --> 00:28:16,720
Speaker 1: to wait a while for those wiggles to get to you?

531
00:28:17,040 --> 00:28:18,960
Speaker 1: And I guess you know. The idea is also that

532
00:28:19,040 --> 00:28:20,920
Speaker 1: if you're closer to the Sun. You're going to feel

533
00:28:20,920 --> 00:28:23,960
Speaker 1: those wiggles first, so there's sort of like a propagation,

534
00:28:24,080 --> 00:28:27,880
Speaker 1: like a ripple of those wiggles that um comes out

535
00:28:27,960 --> 00:28:30,560
Speaker 1: of the sun exactly, and those ripples travel at the

536
00:28:30,600 --> 00:28:33,679
Speaker 1: speed of light. So these gravitational waves is information that

537
00:28:33,760 --> 00:28:37,040
Speaker 1: propagates through the gravitational field. These which really are in

538
00:28:37,119 --> 00:28:41,920
Speaker 1: the end ripples in the curvature of space time because gravity, remember,

539
00:28:42,200 --> 00:28:44,440
Speaker 1: not really a force. It's just the effect of the

540
00:28:44,480 --> 00:28:47,960
Speaker 1: curvature of space time, which is invisible to us except

541
00:28:47,960 --> 00:28:50,200
Speaker 1: for this weird effect that it has on the path

542
00:28:50,360 --> 00:28:53,200
Speaker 1: of particles. And so as you say, if you wiggle

543
00:28:53,280 --> 00:28:56,640
Speaker 1: the Sun, for example, that should change the curvature of space,

544
00:28:56,760 --> 00:29:00,160
Speaker 1: and that causes a gravitational wave with frequency proportion all

545
00:29:00,200 --> 00:29:02,760
Speaker 1: to the wiggling, which is totally analogous to like how

546
00:29:02,880 --> 00:29:06,160
Speaker 1: you create electromagnetic waves. You take an electron which has

547
00:29:06,160 --> 00:29:09,080
Speaker 1: an electric field all through space, and you wiggle it

548
00:29:09,160 --> 00:29:11,840
Speaker 1: in an antenna, for example, at a certain frequency. Then

549
00:29:11,880 --> 00:29:15,840
Speaker 1: it shakes the electromagnetic field. It changes that field which

550
00:29:15,840 --> 00:29:18,400
Speaker 1: is emanating out from the electron, and that shake in

551
00:29:18,400 --> 00:29:21,640
Speaker 1: the electromagnetic field is a photon. It's a wiggle in

552
00:29:21,680 --> 00:29:24,600
Speaker 1: the electromagnetic field, and so in the same wave you

553
00:29:24,640 --> 00:29:27,600
Speaker 1: wiggle the source of gravity like the sun, then you

554
00:29:27,640 --> 00:29:32,680
Speaker 1: get wiggles in the gravitational field, and that's a gravitational wave. Right. Well,

555
00:29:32,720 --> 00:29:34,200
Speaker 1: I wonder if you can get into a little bit

556
00:29:34,200 --> 00:29:37,360
Speaker 1: of a rabbit hole here thinking about what simultaneity is

557
00:29:37,520 --> 00:29:41,000
Speaker 1: and whether or not you can actually measure a wave

558
00:29:41,160 --> 00:29:44,720
Speaker 1: moving or the or to claim that it didn't happen

559
00:29:44,720 --> 00:29:47,320
Speaker 1: at the same time, because you know, as we talked

560
00:29:47,360 --> 00:29:49,200
Speaker 1: about in the last episode, it's kind of hard to

561
00:29:49,200 --> 00:29:51,880
Speaker 1: synchronize clocks and make sure that the wave you didn't

562
00:29:51,880 --> 00:29:53,920
Speaker 1: feel that gravitational wave at the same time that it

563
00:29:54,000 --> 00:29:57,400
Speaker 1: was generated. I mean, simonsonety is complicated and it's not

564
00:29:57,520 --> 00:30:00,680
Speaker 1: trivial or intuitive. We can't think about a luck all

565
00:30:00,720 --> 00:30:04,160
Speaker 1: the way through space and imagine that everybody agrees on

566
00:30:04,200 --> 00:30:06,680
Speaker 1: the order of events. But that doesn't mean and we

567
00:30:06,720 --> 00:30:08,760
Speaker 1: can't talk about it from our frame and say, like,

568
00:30:08,840 --> 00:30:10,920
Speaker 1: what do we think happen firth, what do we see?

569
00:30:11,040 --> 00:30:13,440
Speaker 1: And in the case of gravitational waves, we can actually

570
00:30:13,480 --> 00:30:17,080
Speaker 1: measure their propagation through space. So we have seen gravitational

571
00:30:17,120 --> 00:30:20,360
Speaker 1: waves because we have detectors on Earth that are sensitive

572
00:30:20,400 --> 00:30:22,800
Speaker 1: to these things, and we have multiple detectors and we

573
00:30:22,800 --> 00:30:25,560
Speaker 1: can see them propagating through space because they hit one

574
00:30:25,600 --> 00:30:28,520
Speaker 1: detector before another detector. And this is the way we

575
00:30:28,560 --> 00:30:32,680
Speaker 1: can actually get directional information about gravitational waves. We can say, oh,

576
00:30:32,680 --> 00:30:35,280
Speaker 1: look it hit in New Orleans before it hit in

577
00:30:35,360 --> 00:30:38,400
Speaker 1: Washington and in Italy. Therefore it must have been going

578
00:30:38,480 --> 00:30:41,880
Speaker 1: in that direction. And so that helps us triangulate the

579
00:30:41,920 --> 00:30:44,680
Speaker 1: source of the gravitational wave because we can actually see

580
00:30:44,680 --> 00:30:48,040
Speaker 1: it arriving at different places at different times, which shows

581
00:30:48,040 --> 00:30:50,640
Speaker 1: you that it really is flowing through space at a

582
00:30:50,680 --> 00:30:54,120
Speaker 1: certain speed. M. Well, yeah, I guess if you measure

583
00:30:54,120 --> 00:30:56,520
Speaker 1: it first and if one place and then later in

584
00:30:56,600 --> 00:30:59,440
Speaker 1: the other one, then it's it's moving. It's moving through space. Yeah,

585
00:30:59,480 --> 00:31:01,120
Speaker 1: And we can see the same wiggle, right, It's like

586
00:31:01,160 --> 00:31:04,040
Speaker 1: each of these things have a very characteristic wiggle, usually

587
00:31:04,040 --> 00:31:07,280
Speaker 1: formed by the black hole merger or neutron star murder

588
00:31:07,280 --> 00:31:08,880
Speaker 1: that formed it. So we can tell that it's the

589
00:31:08,920 --> 00:31:12,360
Speaker 1: same gravitational wave. Now, as you said earlier, gravitational waves

590
00:31:12,360 --> 00:31:16,480
Speaker 1: are everywhere in space because every acceleration generates them. When

591
00:31:16,480 --> 00:31:19,000
Speaker 1: you run to the kitchen to get a banana and

592
00:31:19,040 --> 00:31:22,960
Speaker 1: you've accelerated, then you're creating little gravitational waves. Remember that

593
00:31:23,000 --> 00:31:25,480
Speaker 1: gravity is super duper weak, and so the gravity from

594
00:31:25,520 --> 00:31:28,400
Speaker 1: your body or from your banana is really really weak.

595
00:31:28,720 --> 00:31:32,920
Speaker 1: So while it does generate gravitational waves anytime anything accelerates,

596
00:31:33,160 --> 00:31:36,120
Speaker 1: those are basically impossible to see. That's why when we

597
00:31:36,160 --> 00:31:38,840
Speaker 1: look for gravitational waves, we usually look for ones generated

598
00:31:38,880 --> 00:31:43,160
Speaker 1: by incredibly massive objects, like huge stars or like black

599
00:31:43,200 --> 00:31:45,480
Speaker 1: holes with tens of times the mass of the Sun,

600
00:31:45,680 --> 00:31:48,920
Speaker 1: because you need a lot of gravity to generate gravitational

601
00:31:49,000 --> 00:31:51,520
Speaker 1: waves that we can actually see. Right, well, it sorta

602
00:31:51,600 --> 00:31:53,960
Speaker 1: depends how many bananas you eat too, right though, Right Like,

603
00:31:54,040 --> 00:31:56,840
Speaker 1: if you eat enough bananas, you will technically generate a

604
00:31:56,840 --> 00:31:59,480
Speaker 1: big gravitational wave. Exactly, if you just throw everything in

605
00:31:59,520 --> 00:32:01,960
Speaker 1: your free into the black hole and then eat it

606
00:32:01,960 --> 00:32:04,120
Speaker 1: as a smoothie at the other side of the white hole,

607
00:32:04,440 --> 00:32:08,600
Speaker 1: it's gonna taste pretty funny and you're gonna get pretty heavy. Now, confused,

608
00:32:08,640 --> 00:32:10,600
Speaker 1: but it's kind of interesting to think that everything does

609
00:32:10,680 --> 00:32:13,040
Speaker 1: generate a gravitational wave. Like right like, as you said,

610
00:32:13,040 --> 00:32:14,880
Speaker 1: if I jump up and down or move my arm,

611
00:32:14,920 --> 00:32:18,440
Speaker 1: I am generating gravitational wave. And in fact, that gravitational

612
00:32:18,520 --> 00:32:20,800
Speaker 1: wave that I'm generating with my arm. Even though it's

613
00:32:20,800 --> 00:32:23,680
Speaker 1: really small and weak, it is sort of propagating through

614
00:32:23,680 --> 00:32:26,240
Speaker 1: the universe, and technically it is gonna, you know, go

615
00:32:26,360 --> 00:32:28,680
Speaker 1: out to the edge of the universe, right, it will.

616
00:32:28,760 --> 00:32:30,440
Speaker 1: In the same way that if you, like, you know,

617
00:32:30,480 --> 00:32:32,840
Speaker 1: stand at night and shine your flashlight up at the

618
00:32:32,840 --> 00:32:35,720
Speaker 1: sky and turn it on and off, you're sending photons

619
00:32:35,720 --> 00:32:39,200
Speaker 1: which could travel forever, right, billions or trillions of years

620
00:32:39,520 --> 00:32:42,400
Speaker 1: until they hit some alien eyeball on some other planet

621
00:32:42,480 --> 00:32:44,480
Speaker 1: or never. Right, they could just go forever. In that

622
00:32:44,600 --> 00:32:46,880
Speaker 1: same way, everything that we throw out into space could

623
00:32:46,920 --> 00:32:50,120
Speaker 1: go forever. Remember though, that your gravitational waves, they start

624
00:32:50,120 --> 00:32:53,800
Speaker 1: off really weak, and they get weaker with distance because

625
00:32:53,800 --> 00:32:56,400
Speaker 1: the energy that's in the gravitational waves get spread out

626
00:32:56,440 --> 00:32:59,600
Speaker 1: over a larger and larger sphere as they get further

627
00:32:59,640 --> 00:33:02,120
Speaker 1: and further from you. So the strength of these gravitational

628
00:33:02,160 --> 00:33:05,479
Speaker 1: waves goes like one over the distance squared, just like

629
00:33:05,520 --> 00:33:08,400
Speaker 1: all other kinds of radiation. So they start off already weak,

630
00:33:08,480 --> 00:33:11,240
Speaker 1: and then twice as far away they are four times weaker,

631
00:33:11,320 --> 00:33:13,360
Speaker 1: and ten times as far away they are a hundred

632
00:33:13,360 --> 00:33:16,360
Speaker 1: times weaker, And that gets pretty stiff pretty quick. Right,

633
00:33:16,360 --> 00:33:18,760
Speaker 1: But I guess, as far as we know, gravitational waves

634
00:33:18,760 --> 00:33:21,080
Speaker 1: are not sort of quantum, right, So there's no minimum

635
00:33:21,160 --> 00:33:24,680
Speaker 1: size to these waves, is there, right? So technically the

636
00:33:24,800 --> 00:33:26,920
Speaker 1: waves I'm making with my arm right now are going

637
00:33:26,960 --> 00:33:29,160
Speaker 1: to travel throughout the entire U dors. Well, we don't know.

638
00:33:29,200 --> 00:33:31,280
Speaker 1: It's a great question, you know. People might be wondering

639
00:33:31,320 --> 00:33:35,840
Speaker 1: because we compared earlier gravitational waves to photons, and gravitational

640
00:33:35,880 --> 00:33:39,120
Speaker 1: waves are classical objects, meaning that we don't know if

641
00:33:39,160 --> 00:33:41,480
Speaker 1: they are made at the small scale out of some

642
00:33:41,560 --> 00:33:44,800
Speaker 1: quantum unit. So a better analogy is probably not the photon,

643
00:33:44,920 --> 00:33:47,520
Speaker 1: but like a big pulse of light, which might be

644
00:33:47,560 --> 00:33:51,240
Speaker 1: made out of many photons. So gravitational waves might be

645
00:33:51,440 --> 00:33:54,400
Speaker 1: classical objects, meaning it might be smooth and continuous and

646
00:33:54,440 --> 00:33:56,080
Speaker 1: as you say, they could get as small as you like,

647
00:33:56,800 --> 00:34:00,240
Speaker 1: or they might be made out of gravitons like the

648
00:34:00,360 --> 00:34:03,640
Speaker 1: quantum unit of gravity. But we just don't know because

649
00:34:03,640 --> 00:34:06,760
Speaker 1: we don't have a quantum theory of gravity, so we

650
00:34:06,760 --> 00:34:10,239
Speaker 1: can see gravitational waves without knowing whether or not there

651
00:34:10,280 --> 00:34:14,160
Speaker 1: are even are gravitons. Gravitons, if they exist, would be

652
00:34:14,200 --> 00:34:17,799
Speaker 1: like tiny little pieces of a gravitational wave. Each one

653
00:34:17,880 --> 00:34:21,640
Speaker 1: might have like tend to the sixteen gravitons. Yeah, and

654
00:34:21,760 --> 00:34:23,360
Speaker 1: you know, I think this sort of gets down to

655
00:34:23,480 --> 00:34:26,040
Speaker 1: the question of the episode, because you know, when you

656
00:34:26,080 --> 00:34:29,080
Speaker 1: shoot a flashlight out into this guy, you're sending out photons.

657
00:34:29,080 --> 00:34:32,080
Speaker 1: And technically those photons could go to the ends of

658
00:34:32,080 --> 00:34:34,839
Speaker 1: the universe and keep going. But more likely they're gonna

659
00:34:34,920 --> 00:34:37,520
Speaker 1: you know, hit a dust particle and bounce or get

660
00:34:37,560 --> 00:34:41,040
Speaker 1: absorbed or um, something happens to them when they hit

661
00:34:41,160 --> 00:34:43,400
Speaker 1: something else. And also, if you think about the analogy

662
00:34:43,400 --> 00:34:46,040
Speaker 1: of like a ripple in a lake, that wave, that

663
00:34:46,120 --> 00:34:48,840
Speaker 1: water wave loses energy as it goes from the friction

664
00:34:48,920 --> 00:34:52,520
Speaker 1: of the of the molecules. But the gravitational waves are different, right,

665
00:34:52,560 --> 00:34:56,680
Speaker 1: They sort of don't actually hit things when they hit things. Yeah,

666
00:34:56,680 --> 00:35:00,600
Speaker 1: gravitational waves are incredible because they in principle pass right

667
00:35:00,640 --> 00:35:04,000
Speaker 1: through stuff. You know, you have some like huge gas cloud.

668
00:35:04,160 --> 00:35:06,239
Speaker 1: Photons might not be able to penetrate it because they've

669
00:35:06,239 --> 00:35:08,879
Speaker 1: got to interact with all the stuff in the gas cloud.

670
00:35:08,920 --> 00:35:11,200
Speaker 1: They could absorbed by it, or they get reflected by

671
00:35:11,239 --> 00:35:15,960
Speaker 1: and whatever. Gravitational waves are ripples in the underlying substrate

672
00:35:16,080 --> 00:35:19,080
Speaker 1: of space itself, right, so they pass right through these

673
00:35:19,080 --> 00:35:22,279
Speaker 1: gas clouds. They can go basically through anything. They can

674
00:35:22,320 --> 00:35:25,680
Speaker 1: go through neutron stars, right, some of the densest non

675
00:35:25,719 --> 00:35:28,600
Speaker 1: black hole material in the universe. And so in that sense,

676
00:35:28,640 --> 00:35:31,600
Speaker 1: they're an incredible way to see the universe because they

677
00:35:31,600 --> 00:35:35,560
Speaker 1: can pass through stuff that is otherwise totally opaque to us.

678
00:35:36,080 --> 00:35:39,000
Speaker 1: So they're incredible like new kind of eyeball that like,

679
00:35:39,440 --> 00:35:42,080
Speaker 1: you know, excuse the analogy, but X rays everything in

680
00:35:42,120 --> 00:35:45,160
Speaker 1: the universe. One thing we're really excited about is using

681
00:35:45,200 --> 00:35:48,920
Speaker 1: them to see even further back in time. You know,

682
00:35:49,000 --> 00:35:51,320
Speaker 1: the earliest light that we can see from the universe

683
00:35:51,360 --> 00:35:54,640
Speaker 1: comes from the cosmic microwave background radiation, which is from

684
00:35:54,719 --> 00:35:58,359
Speaker 1: the first moment when the universe was transparent to photons,

685
00:35:58,440 --> 00:36:02,120
Speaker 1: like and years after the Big Bang, universe went from

686
00:36:02,400 --> 00:36:06,359
Speaker 1: opaque plasma to transparent gas so the photons could fly free.

687
00:36:06,480 --> 00:36:09,000
Speaker 1: We can't see before that with photons, but we might

688
00:36:09,080 --> 00:36:12,439
Speaker 1: be able to see before that with gravitational waves. People

689
00:36:12,480 --> 00:36:16,400
Speaker 1: are looking for gravitational waves created during the Big Bang

690
00:36:16,480 --> 00:36:18,879
Speaker 1: that we might even be able to see. Yeah, that's

691
00:36:18,880 --> 00:36:21,800
Speaker 1: pretty amazing, and so I guess what happens. Then we

692
00:36:21,880 --> 00:36:25,480
Speaker 1: have a gravitational wave hits something solid like a planet,

693
00:36:25,760 --> 00:36:28,920
Speaker 1: like it just totally goes through it, or does it

694
00:36:28,960 --> 00:36:30,920
Speaker 1: lose a little bit of energy? Does some of the

695
00:36:31,360 --> 00:36:35,560
Speaker 1: gravitational wave get absorbed, or does it really um you know,

696
00:36:35,680 --> 00:36:37,880
Speaker 1: nothing happens to the way. It's a great question. So

697
00:36:37,920 --> 00:36:41,000
Speaker 1: what happens to the stuff that's in space when a

698
00:36:41,040 --> 00:36:43,400
Speaker 1: gravitational wave passes through it? And you're right, this is

699
00:36:43,400 --> 00:36:45,600
Speaker 1: critical to understand when we get into the question of

700
00:36:45,640 --> 00:36:47,520
Speaker 1: what happens when it hits a black hole? So in

701
00:36:47,520 --> 00:36:50,440
Speaker 1: one sense, things do happen, right, Like we can see

702
00:36:50,560 --> 00:36:53,839
Speaker 1: gravitational waves because they do have an effect on our

703
00:36:53,880 --> 00:36:56,680
Speaker 1: physical systems. Like the way that we detect them is

704
00:36:56,719 --> 00:37:00,239
Speaker 1: that we measure distances changing remember gravitational way, it is

705
00:37:00,280 --> 00:37:03,120
Speaker 1: a change in the curvature of space. The curvature of

706
00:37:03,160 --> 00:37:05,319
Speaker 1: space really is another way of saying, like how far

707
00:37:05,400 --> 00:37:08,319
Speaker 1: apart are different parts of space to each other? You know,

708
00:37:08,400 --> 00:37:11,880
Speaker 1: you bend space by changing the intrinsic curvature of space

709
00:37:11,920 --> 00:37:14,400
Speaker 1: by saying, like this piece of space is now closer

710
00:37:14,440 --> 00:37:16,279
Speaker 1: than that one. And so the natural path or a

711
00:37:16,280 --> 00:37:18,799
Speaker 1: photon is what looks like a curve, it's really a

712
00:37:18,840 --> 00:37:21,680
Speaker 1: straight line through this bent space. And so the way

713
00:37:21,719 --> 00:37:23,960
Speaker 1: we detect them is by having these laser beams which

714
00:37:23,960 --> 00:37:27,120
Speaker 1: are shooting back and forth between mirrors constantly measuring the

715
00:37:27,160 --> 00:37:30,480
Speaker 1: distance between those mirrors. And so we see the gravitational

716
00:37:30,520 --> 00:37:33,680
Speaker 1: wave because it changes the distance between those mirrors. Because

717
00:37:33,680 --> 00:37:36,160
Speaker 1: it actually shrinks the space between them. We can measure

718
00:37:36,160 --> 00:37:37,839
Speaker 1: that because we know the speed of light and it's

719
00:37:37,880 --> 00:37:40,640
Speaker 1: bouncing back, we can time essentially the distance between the

720
00:37:40,680 --> 00:37:43,040
Speaker 1: speed of light. It's a bit more complicated because the

721
00:37:43,040 --> 00:37:45,760
Speaker 1: measurement has to be very precise, so they use interferometry.

722
00:37:46,000 --> 00:37:49,200
Speaker 1: We have a whole episode and video about that. But basically,

723
00:37:49,239 --> 00:37:52,239
Speaker 1: it does shrink the stuff in space, so you can

724
00:37:52,280 --> 00:37:55,160
Speaker 1: measure those distances, but then it shrinks it back, right,

725
00:37:55,200 --> 00:37:57,680
Speaker 1: so it squeezes it and then it comes back. So

726
00:37:57,719 --> 00:38:01,160
Speaker 1: from that sense, no energy is lost, right, space is rippled,

727
00:38:01,400 --> 00:38:04,359
Speaker 1: but then the gravitational wave just passes on. Right. It's

728
00:38:04,400 --> 00:38:06,080
Speaker 1: sort of like like I was thinking, it's sort of

729
00:38:06,080 --> 00:38:08,200
Speaker 1: like a slink. If you take a slinking, you stretch

730
00:38:08,239 --> 00:38:11,319
Speaker 1: it out and then you sort of pinch one bit

731
00:38:11,400 --> 00:38:13,760
Speaker 1: of it and then let go. It's gonna that pinching

732
00:38:13,840 --> 00:38:15,960
Speaker 1: is sort of going to propagate, right, It's gonna squeeze

733
00:38:16,040 --> 00:38:18,040
Speaker 1: the little bit of slinky next to it, but then

734
00:38:18,080 --> 00:38:20,560
Speaker 1: it's gonna stretch out, and then that's gonna squeeze the

735
00:38:20,680 --> 00:38:22,480
Speaker 1: little bit of slinky next to that one. And so

736
00:38:22,600 --> 00:38:25,400
Speaker 1: like space, you see this kind of squeezing and stretching

737
00:38:25,400 --> 00:38:27,319
Speaker 1: of space. But as you say, I think that's really

738
00:38:27,360 --> 00:38:30,040
Speaker 1: kind of the question is like, is any energy going

739
00:38:30,120 --> 00:38:33,960
Speaker 1: into moving and squeezing the stuff that's in this space, right,

740
00:38:34,040 --> 00:38:37,080
Speaker 1: because you're you're technically sort of accelerating it, right, Like

741
00:38:37,120 --> 00:38:40,480
Speaker 1: if a gravitational ways passes through the Earth, you're squeezing

742
00:38:40,800 --> 00:38:43,120
Speaker 1: all the Earth molecules together a little bit and all

743
00:38:43,239 --> 00:38:45,480
Speaker 1: then spreading them out a little bit. Doesn't it take

744
00:38:45,560 --> 00:38:48,400
Speaker 1: energy to squeeze them and also to unsqueeze them. So

745
00:38:48,440 --> 00:38:50,480
Speaker 1: this is a topic of great debate in the nineteen

746
00:38:50,600 --> 00:38:54,640
Speaker 1: fifties about whether gravitational waves can actually deposit energy into

747
00:38:54,719 --> 00:38:57,080
Speaker 1: matter or whether they just sort of like pass through

748
00:38:57,120 --> 00:38:59,480
Speaker 1: taking their energy with them. And find me came up

749
00:38:59,480 --> 00:39:01,359
Speaker 1: with a great way of thinking about this. It's called

750
00:39:01,360 --> 00:39:04,759
Speaker 1: the sticky bead example. And so imagine like some rod

751
00:39:04,880 --> 00:39:07,040
Speaker 1: and this rod is like really tightly held together with

752
00:39:07,080 --> 00:39:09,480
Speaker 1: atomic forces, and then you have beads on that rod

753
00:39:09,520 --> 00:39:11,799
Speaker 1: that can slide up and down, and so as the

754
00:39:11,800 --> 00:39:14,600
Speaker 1: gravitational wave comes through, the rod is sort of like

755
00:39:14,719 --> 00:39:17,440
Speaker 1: held to a fixed length by the atomic forces, and

756
00:39:17,440 --> 00:39:19,920
Speaker 1: the beads will be slid back and forth by the

757
00:39:19,960 --> 00:39:24,440
Speaker 1: gravitational wave because the relative distances between the beads will change,

758
00:39:24,480 --> 00:39:26,279
Speaker 1: but they'll slide back and forth and they'll end up

759
00:39:26,320 --> 00:39:28,640
Speaker 1: in the same position because there's no friction. But then

760
00:39:28,680 --> 00:39:31,239
Speaker 1: if you add friction to it, then what happens as

761
00:39:31,280 --> 00:39:33,520
Speaker 1: they slide back and forth on the rod is that

762
00:39:33,560 --> 00:39:36,759
Speaker 1: they do heat up the rod, and that takes some

763
00:39:36,880 --> 00:39:39,919
Speaker 1: of the energy from the gravitational waves. The answer from

764
00:39:39,920 --> 00:39:44,080
Speaker 1: this thought experiment is that the gravitational wave can deposit

765
00:39:44,239 --> 00:39:47,200
Speaker 1: some energy in this matter as it's passing through if

766
00:39:47,200 --> 00:39:50,120
Speaker 1: it generates friction between stuff. If some stuff resists the

767
00:39:50,160 --> 00:39:53,200
Speaker 1: motions of gravitational wave and other stuff doesn't, so you

768
00:39:53,200 --> 00:39:57,000
Speaker 1: get friction sliding between them. Right, But I guess wouldn't

769
00:39:57,000 --> 00:40:00,279
Speaker 1: everything have friction to them, right? Like nothing is quite

770
00:40:00,320 --> 00:40:03,040
Speaker 1: held together by perfect spring exactly, So there's nothing that's

771
00:40:03,080 --> 00:40:07,120
Speaker 1: really friction lists, So everything has some internal friction. Even

772
00:40:07,120 --> 00:40:10,720
Speaker 1: those mirrors in Lego right where they're measuring these gravitational waves.

773
00:40:10,960 --> 00:40:12,840
Speaker 1: They're held up on the wall, and the wall is

774
00:40:13,080 --> 00:40:15,680
Speaker 1: part of a larger cavity and his internal friction in

775
00:40:15,719 --> 00:40:18,120
Speaker 1: that whole setup. And so the answer in the end

776
00:40:18,280 --> 00:40:21,719
Speaker 1: is that gravitational waves do deposit energy and stuff as

777
00:40:21,760 --> 00:40:24,120
Speaker 1: they pass through, and so they do get fainter and

778
00:40:24,200 --> 00:40:27,279
Speaker 1: fainter as they propagate out through the universe. They do

779
00:40:27,360 --> 00:40:29,239
Speaker 1: get it sort of absorbed a little bit. But I

780
00:40:29,239 --> 00:40:31,520
Speaker 1: guess I'm thinking, you know, kind of like a wave

781
00:40:31,560 --> 00:40:33,719
Speaker 1: in the ocean or at the at the beach. You know,

782
00:40:33,880 --> 00:40:36,200
Speaker 1: a wave is not just like in one spot. It's

783
00:40:36,239 --> 00:40:38,560
Speaker 1: a long piece of the coast, right Like a wave

784
00:40:38,640 --> 00:40:41,319
Speaker 1: is really long, and if it goes through me, I

785
00:40:41,400 --> 00:40:43,960
Speaker 1: might block a little bit of it where I am,

786
00:40:44,120 --> 00:40:46,000
Speaker 1: but the whole wave's still going to keep going, and

787
00:40:46,000 --> 00:40:49,239
Speaker 1: in fact, it's sort of almost reassembles itself after it

788
00:40:49,320 --> 00:40:51,640
Speaker 1: hits me. A wave is a very long object, and

789
00:40:51,680 --> 00:40:53,600
Speaker 1: in this case, a gravitational wave is more like a

790
00:40:53,640 --> 00:40:57,040
Speaker 1: sphere right from a black hole Merger. Gravitational waves admit

791
00:40:57,160 --> 00:40:59,440
Speaker 1: in every direction, and so if you put hoges in

792
00:40:59,480 --> 00:41:01,520
Speaker 1: one direction and you will get heated up by the

793
00:41:01,520 --> 00:41:04,040
Speaker 1: gravitational way, but the rest of it won't be impacted

794
00:41:04,080 --> 00:41:06,120
Speaker 1: at all, and you can calculate what would happen after

795
00:41:06,160 --> 00:41:08,320
Speaker 1: it hits you, right, the way sort of reforms, so

796
00:41:08,400 --> 00:41:10,879
Speaker 1: it's a little bit distorted on the other side. All right,

797
00:41:10,920 --> 00:41:13,719
Speaker 1: Well that's a gravitational wave. They're pretty interesting. They are

798
00:41:13,840 --> 00:41:16,680
Speaker 1: not quite unstoppable, right, You can't stop him if you

799
00:41:16,800 --> 00:41:19,680
Speaker 1: have enough mass, although they are so large, and maybe

800
00:41:19,719 --> 00:41:22,520
Speaker 1: they might ignore an obstacle that it's in their path.

801
00:41:22,600 --> 00:41:24,840
Speaker 1: And so let's get into the ultimate question of what

802
00:41:24,960 --> 00:41:27,960
Speaker 1: happens when a gravitational wave meets a black hole? Which

803
00:41:28,000 --> 00:41:30,680
Speaker 1: one will get matter? But first let's take a quick break.

804
00:41:43,680 --> 00:41:45,960
Speaker 1: All right, we're talking about the ultimate meetup of what

805
00:41:46,000 --> 00:41:49,319
Speaker 1: happens when a gravitational wave meets a black hole? And

806
00:41:49,480 --> 00:41:51,560
Speaker 1: I guess, first of all, Daniel, is it a friendly meeting,

807
00:41:51,760 --> 00:41:54,400
Speaker 1: like are they looking forward to seeing hanging out or

808
00:41:55,360 --> 00:41:59,680
Speaker 1: is this a fight to be had? I think black

809
00:41:59,719 --> 00:42:02,360
Speaker 1: hole and gravitational waves it just sort of like screaming

810
00:42:02,360 --> 00:42:04,480
Speaker 1: through the universe. So I think they're just going to

811
00:42:04,560 --> 00:42:07,560
Speaker 1: get matter and matter about the matter. And I guess

812
00:42:07,640 --> 00:42:10,400
Speaker 1: they are they going to turn red or green? And

813
00:42:10,520 --> 00:42:13,279
Speaker 1: are are there gamma rays involved? Because right, black holes

814
00:42:13,280 --> 00:42:16,360
Speaker 1: are are full of gamma rays. Yeah, well, I think

815
00:42:16,440 --> 00:42:19,320
Speaker 1: that as they curve space, they tend to redshift things,

816
00:42:19,400 --> 00:42:21,440
Speaker 1: so they're gonna get redder and redder, right, which is

817
00:42:21,480 --> 00:42:24,000
Speaker 1: the color of anger and comic books, isn't it all? Right? Well,

818
00:42:24,040 --> 00:42:26,520
Speaker 1: that's the ultimate comic book question. Here, what happens when

819
00:42:26,520 --> 00:42:31,000
Speaker 1: a gravitational wave meets a black hole? And uh, what happens, Daniel?

820
00:42:31,040 --> 00:42:33,600
Speaker 1: Does it crack the black hole? Does a gravitational wave

821
00:42:33,680 --> 00:42:36,560
Speaker 1: gets sucked in or split in half? So once again

822
00:42:36,760 --> 00:42:39,520
Speaker 1: black holes win? Right? Black holes seem to win every

823
00:42:39,560 --> 00:42:41,839
Speaker 1: single time you throw something at them, another black hole,

824
00:42:41,920 --> 00:42:45,320
Speaker 1: a neutron, star, or a banana, even a gravitational wave.

825
00:42:45,760 --> 00:42:48,279
Speaker 1: You know, if you throw anything with energy at a

826
00:42:48,360 --> 00:42:50,719
Speaker 1: black hole, it will just gobble it up. And that

827
00:42:50,800 --> 00:42:55,280
Speaker 1: includes gravitational waves. You know, in the end, gravitational waves,

828
00:42:55,280 --> 00:42:58,600
Speaker 1: there are ripples in space and time, and they can

829
00:42:58,640 --> 00:43:02,400
Speaker 1: be affected by the curvature of space the same way

830
00:43:02,440 --> 00:43:05,479
Speaker 1: the like photons can't. Right, Photons don't have any mass,

831
00:43:05,520 --> 00:43:08,279
Speaker 1: but they are affected by the curvature of space. They

832
00:43:08,320 --> 00:43:12,239
Speaker 1: are red shifted by gravitational expansion, they are distorted by

833
00:43:12,320 --> 00:43:16,480
Speaker 1: gravitational lensing, they are captured by black holes. All the

834
00:43:16,560 --> 00:43:20,880
Speaker 1: same things also apply to gravitational waves. Right, Well, I

835
00:43:20,880 --> 00:43:23,800
Speaker 1: guess the question is, you know what might be confusing

836
00:43:23,920 --> 00:43:26,360
Speaker 1: is that, you know, a black hole is a distortion

837
00:43:26,920 --> 00:43:29,800
Speaker 1: in space time. Right, It's like space sort of curves

838
00:43:30,360 --> 00:43:33,279
Speaker 1: towards the center of the black hole, and a gravitational

839
00:43:33,280 --> 00:43:38,120
Speaker 1: wave is a ripple in that space time. So does

840
00:43:38,160 --> 00:43:41,439
Speaker 1: it even make sense for a gravitational wave to hit

841
00:43:41,520 --> 00:43:44,640
Speaker 1: a black hole? Right? It's it's sort of like, you know,

842
00:43:44,680 --> 00:43:46,799
Speaker 1: if it's a ripple and a rope, but the rope

843
00:43:46,880 --> 00:43:50,399
Speaker 1: is just going down the drain. Nothing really collides, it's

844
00:43:50,440 --> 00:43:53,840
Speaker 1: just ripples down the rope into the hole. Be careful

845
00:43:53,880 --> 00:43:55,759
Speaker 1: about how we think about a black holes. Right. There

846
00:43:55,760 --> 00:43:58,680
Speaker 1: may be some mass concentrated at the center, but really,

847
00:43:58,719 --> 00:44:00,479
Speaker 1: when we're talking about the black hole or talking about

848
00:44:00,480 --> 00:44:03,000
Speaker 1: the event horizon, the event horizon is not a surface

849
00:44:03,000 --> 00:44:04,520
Speaker 1: in the way that you can stand on. It's just

850
00:44:04,560 --> 00:44:08,000
Speaker 1: a location past which nothing can emerge. And so a

851
00:44:08,000 --> 00:44:10,880
Speaker 1: gravitational wave, you should think about it as energy the

852
00:44:10,880 --> 00:44:13,640
Speaker 1: same way you think about a banana as energy. Bananas

853
00:44:13,640 --> 00:44:16,600
Speaker 1: made of particles. They're just ripples in those quantum fields,

854
00:44:16,680 --> 00:44:20,520
Speaker 1: and so a gravitational wave is ripples in space itself,

855
00:44:20,640 --> 00:44:23,080
Speaker 1: but in the end, that's just energy. When that energy

856
00:44:23,239 --> 00:44:27,200
Speaker 1: enters into the region around this dense mass inside the

857
00:44:27,239 --> 00:44:30,480
Speaker 1: event horizon, and that energy is affected by the curvature

858
00:44:30,520 --> 00:44:33,279
Speaker 1: of space itself, even though that energy is in the

859
00:44:33,320 --> 00:44:36,560
Speaker 1: curvature of space itself, right, I guess I'm thinking. You know,

860
00:44:36,600 --> 00:44:39,320
Speaker 1: it's sort of like the wave. The energy doesn't really

861
00:44:40,040 --> 00:44:44,400
Speaker 1: um go anywhere or disappears or gets absorbed. It just

862
00:44:44,480 --> 00:44:46,560
Speaker 1: sort of falls into the hole like everything else. It

863
00:44:46,600 --> 00:44:49,840
Speaker 1: falls into the hole and eventually ends up at the singularity.

864
00:44:50,040 --> 00:44:52,480
Speaker 1: If you believe in classical general relativity that there are

865
00:44:52,560 --> 00:44:55,879
Speaker 1: singularities at the hearts of black holes. Remember, singularities are

866
00:44:55,920 --> 00:44:59,279
Speaker 1: like endpoints, right, you throw a particle into singularity, there's

867
00:44:59,280 --> 00:45:00,840
Speaker 1: no direction for to go, which is sort of like

868
00:45:01,239 --> 00:45:03,800
Speaker 1: ends there. That's one reason why we think maybe general

869
00:45:03,840 --> 00:45:07,040
Speaker 1: relativity is wrong, because it seems like information is being

870
00:45:07,040 --> 00:45:09,600
Speaker 1: deleted from the universe when it goes into the singularity.

871
00:45:09,600 --> 00:45:13,000
Speaker 1: But according to classical general relativity, then yeah, the gravitational

872
00:45:13,000 --> 00:45:16,239
Speaker 1: wave just gets like slurped up into the singularity and

873
00:45:16,320 --> 00:45:19,680
Speaker 1: ends there. Just adds its energy to the singularity. Doesn't

874
00:45:19,760 --> 00:45:23,920
Speaker 1: matter what form of energy you're in. Photon banana, gravitational

875
00:45:23,960 --> 00:45:27,400
Speaker 1: wave anything that enters in the event horizon just contributes

876
00:45:27,520 --> 00:45:29,920
Speaker 1: to the mass of that black hole. Right, But we

877
00:45:29,960 --> 00:45:32,200
Speaker 1: talked about earlier how like if you throw a banana

878
00:45:32,239 --> 00:45:34,960
Speaker 1: into a black hole, never actually falls in because you know,

879
00:45:35,040 --> 00:45:37,640
Speaker 1: time slows down and it just looks frozen at the

880
00:45:37,680 --> 00:45:40,080
Speaker 1: surface of a black hole. Does the same thing happen

881
00:45:40,160 --> 00:45:42,719
Speaker 1: to a gravitational wave, Like you'll see the ripple sort

882
00:45:42,719 --> 00:45:45,719
Speaker 1: of ripple in and then stop at this at the surface. Yeah,

883
00:45:45,719 --> 00:45:48,120
Speaker 1: the same thing happens, but remember there's more gravitational wave

884
00:45:48,239 --> 00:45:50,600
Speaker 1: coming behind it. Usually, like, unless you have a single

885
00:45:50,640 --> 00:45:53,839
Speaker 1: burst of gravitational waves, then there's a train of these

886
00:45:53,880 --> 00:45:57,439
Speaker 1: gravitational ripples coming through the universe, and so each one

887
00:45:57,600 --> 00:45:59,920
Speaker 1: is growing the black hole a little bit, helping the

888
00:46:00,000 --> 00:46:02,800
Speaker 1: one that came before it actually fall past the event horizon.

889
00:46:03,000 --> 00:46:05,640
Speaker 1: So it's more like a long chain of bananas than

890
00:46:05,680 --> 00:46:10,440
Speaker 1: an individual banana. That's delicious. But you were also asking

891
00:46:10,480 --> 00:46:13,800
Speaker 1: earlier about like the whole wavefront of the gravitational wave.

892
00:46:13,960 --> 00:46:16,799
Speaker 1: Because gravitational waves are affected by black holes, they can

893
00:46:16,840 --> 00:46:20,640
Speaker 1: also be like lensed by black holes. So you can

894
00:46:20,640 --> 00:46:24,880
Speaker 1: have like gravitational lensing of gravitational waves as they pass

895
00:46:25,000 --> 00:46:27,720
Speaker 1: around a black hole. So the ones that like actually

896
00:46:27,760 --> 00:46:30,359
Speaker 1: hit the event horizon are slurped in, but the ones

897
00:46:30,400 --> 00:46:33,360
Speaker 1: that go nearby, they can get like bent around the

898
00:46:33,400 --> 00:46:35,839
Speaker 1: black hole, right, and even get sort of like bent

899
00:46:35,960 --> 00:46:39,719
Speaker 1: back right reflected back towards the source of the gravitational wave. Yeah,

900
00:46:39,760 --> 00:46:41,719
Speaker 1: they absolutely could. In the same way. If you look

901
00:46:41,880 --> 00:46:44,520
Speaker 1: near a black hole, you're seeing all sorts of weird distortions,

902
00:46:44,520 --> 00:46:47,000
Speaker 1: Like you can see the other side of the event horizon,

903
00:46:47,040 --> 00:46:48,759
Speaker 1: and you can see stuff that we used around the

904
00:46:48,800 --> 00:46:51,000
Speaker 1: black hole and came back at you. Then you can

905
00:46:51,000 --> 00:46:54,360
Speaker 1: get the same effects with gravitational waves. And so for example,

906
00:46:54,400 --> 00:46:57,719
Speaker 1: if you have the bright source of gravitational waves and

907
00:46:57,760 --> 00:47:00,440
Speaker 1: then between you and that bright source is a black hole,

908
00:47:00,600 --> 00:47:02,680
Speaker 1: what would you see. You would see a little shadow,

909
00:47:03,080 --> 00:47:05,719
Speaker 1: or you would see gravitational waves coming in all directions,

910
00:47:05,760 --> 00:47:08,239
Speaker 1: except you would see this little shadow, just the same

911
00:47:08,280 --> 00:47:10,480
Speaker 1: way we saw a picture of a black hole recently,

912
00:47:10,760 --> 00:47:12,520
Speaker 1: right that was in the X ray. We saw an

913
00:47:12,520 --> 00:47:15,879
Speaker 1: accretion disc around a little shadow. So you would see

914
00:47:15,880 --> 00:47:19,480
Speaker 1: a gravitational wave shadow that's gobbling up some of the

915
00:47:19,480 --> 00:47:22,080
Speaker 1: black holes, but around it you would see these other

916
00:47:22,120 --> 00:47:25,239
Speaker 1: gravitational waves that are like lensed and distorted by the

917
00:47:25,280 --> 00:47:29,160
Speaker 1: black hole m interesting and with the gravitational wave also

918
00:47:29,200 --> 00:47:31,680
Speaker 1: continued to making the black hole bigger. It would right,

919
00:47:31,719 --> 00:47:33,920
Speaker 1: absolutely because it's got energy. But you know, there's an

920
00:47:33,920 --> 00:47:36,440
Speaker 1: important caveat here, which is that we're assuming that the

921
00:47:36,440 --> 00:47:40,080
Speaker 1: gravitational wave itself is pretty small, that like, relative to

922
00:47:40,120 --> 00:47:42,319
Speaker 1: the mass of the black hole, it's not that big

923
00:47:42,320 --> 00:47:45,320
Speaker 1: a deal because black holes typically have very large masses

924
00:47:45,320 --> 00:47:48,600
Speaker 1: and gravitational waves typically don't have that much energy. So

925
00:47:48,640 --> 00:47:51,960
Speaker 1: we're assuming basically like the black hole is fundamentally unchanged.

926
00:47:52,000 --> 00:47:54,239
Speaker 1: Maybe it grows a tiny bit, but it's not like

927
00:47:54,360 --> 00:47:57,240
Speaker 1: really changing the structure of space time around the black hole.

928
00:47:57,360 --> 00:47:59,960
Speaker 1: And then we're using that set up to like saw

929
00:48:00,000 --> 00:48:02,480
Speaker 1: all the wave equation for the gravitational wave in the

930
00:48:02,520 --> 00:48:04,960
Speaker 1: presence of an unchanged black hole, what would happen to

931
00:48:05,000 --> 00:48:09,000
Speaker 1: a gravitational wave If, however, the gravitational wave is like enormous,

932
00:48:09,239 --> 00:48:13,480
Speaker 1: is like really big, it's monster two supermassive black holes

933
00:48:13,480 --> 00:48:15,960
Speaker 1: have merged, then the kind of conation gets more complicated

934
00:48:16,200 --> 00:48:18,480
Speaker 1: because you can't assume that the gravitational wave is going

935
00:48:18,560 --> 00:48:21,200
Speaker 1: to not fundamentally change the black hole. And then it's

936
00:48:21,200 --> 00:48:23,239
Speaker 1: trickier to say exactly what happens. You need to like

937
00:48:23,600 --> 00:48:26,680
Speaker 1: fully solve the Einstein equations. You might get some weird

938
00:48:26,719 --> 00:48:28,799
Speaker 1: distortion to the black hole, but in the end, all

939
00:48:28,800 --> 00:48:32,239
Speaker 1: that energy is going to go into a bigger black hole. Well,

940
00:48:32,239 --> 00:48:34,440
Speaker 1: it's word of the thing that a gravitational wave has

941
00:48:35,080 --> 00:48:38,040
Speaker 1: energy in the traditional sense, because, as we talked about

942
00:48:38,040 --> 00:48:41,440
Speaker 1: it before in the podcast, anything with energy also bend

943
00:48:41,520 --> 00:48:45,040
Speaker 1: space and attracts other things. So it's almost like this

944
00:48:45,239 --> 00:48:49,440
Speaker 1: ripple in space is also rippling in space or you know,

945
00:48:49,560 --> 00:48:52,440
Speaker 1: attracting things. And the energy we're talking about is enormous.

946
00:48:52,560 --> 00:48:55,399
Speaker 1: You know, when two black holes merge, maybe they start

947
00:48:55,400 --> 00:48:58,080
Speaker 1: out each having like fifty times the mass of our Sun,

948
00:48:58,560 --> 00:49:01,120
Speaker 1: they don't form a black hole that has a hundred

949
00:49:01,120 --> 00:49:03,200
Speaker 1: times the mass of the Sun, and it ends up

950
00:49:03,239 --> 00:49:05,560
Speaker 1: with something like eighty times the mass of the Sun,

951
00:49:05,960 --> 00:49:09,239
Speaker 1: and the rest of it goes into gravitational waves. Just

952
00:49:09,320 --> 00:49:11,560
Speaker 1: not for a moment and think about how much energy

953
00:49:11,600 --> 00:49:14,320
Speaker 1: we're talking about. We're talking about all the energy is

954
00:49:14,360 --> 00:49:18,120
Speaker 1: stored in twenty times the mass of our Sun. Remember that,

955
00:49:18,160 --> 00:49:21,719
Speaker 1: like a single raisin a gram of matter has as

956
00:49:21,800 --> 00:49:25,480
Speaker 1: much energy as a nuclear bomb, right, So now imagine

957
00:49:25,480 --> 00:49:27,719
Speaker 1: how much energy is stored in the sun and now

958
00:49:27,760 --> 00:49:30,520
Speaker 1: twenty of those. So we're not talking about a small

959
00:49:30,560 --> 00:49:34,319
Speaker 1: amount of energy here. We're talking about incredible cosmic quantities

960
00:49:34,360 --> 00:49:37,719
Speaker 1: of energy radiated out through the universe. Right, But it

961
00:49:37,960 --> 00:49:40,600
Speaker 1: is the black hole at all affected by the graptational wave,

962
00:49:40,719 --> 00:49:42,799
Speaker 1: Like does it get even like squeezed a little bit,

963
00:49:43,000 --> 00:49:45,680
Speaker 1: or or you know, does it kind of like moving

964
00:49:45,880 --> 00:49:48,120
Speaker 1: a bit at all? Or is does black hole literally

965
00:49:48,200 --> 00:49:51,040
Speaker 1: totally ignore the gravitation wave and just sucks at it.

966
00:49:51,040 --> 00:49:53,480
Speaker 1: It definitely is affected by it. And as the gravitational

967
00:49:53,520 --> 00:49:56,000
Speaker 1: wave gets larger and larger, you start to approach the

968
00:49:56,000 --> 00:49:58,600
Speaker 1: case we talked about recently, which is like two black

969
00:49:58,640 --> 00:50:02,200
Speaker 1: holes merging. When two black holes merge, then you don't

970
00:50:02,239 --> 00:50:05,040
Speaker 1: just have like a big spherical event horizon. You get

971
00:50:05,080 --> 00:50:07,799
Speaker 1: this weird blob that forms as they merge, and it

972
00:50:07,840 --> 00:50:10,879
Speaker 1: becomes a peanut and eventually becomes a sphere. So something

973
00:50:10,920 --> 00:50:13,640
Speaker 1: similar would happen if you had a super powerful gravitational

974
00:50:13,719 --> 00:50:16,760
Speaker 1: wave that was approaching a black hole. It would distort

975
00:50:16,800 --> 00:50:19,120
Speaker 1: the shape of the event horizon. You would like grow

976
00:50:19,160 --> 00:50:22,200
Speaker 1: it out in one direction for another direction. Eventually a

977
00:50:22,200 --> 00:50:24,719
Speaker 1: black hole would like stabilize and thermalize and get into

978
00:50:24,719 --> 00:50:28,040
Speaker 1: equilibrium and become a sphere again. But momentarily it would

979
00:50:28,040 --> 00:50:30,480
Speaker 1: look really weird. And figure out exactly how that would look,

980
00:50:30,480 --> 00:50:33,560
Speaker 1: you'd have to solve the Einstein equations for that particular setup,

981
00:50:33,600 --> 00:50:36,040
Speaker 1: which is really hairy. Well, it's you sort of make

982
00:50:36,080 --> 00:50:39,640
Speaker 1: it sound like the black hole winds over the gravitational wave,

983
00:50:39,800 --> 00:50:41,960
Speaker 1: but I sort of feel kind of the opposite, because

984
00:50:42,200 --> 00:50:45,839
Speaker 1: gravitational wave is not just huge, it's sort of like

985
00:50:46,000 --> 00:50:49,160
Speaker 1: it's the size of basically the all the entire universe,

986
00:50:49,280 --> 00:50:51,919
Speaker 1: right like when two black holes collide, or a black

987
00:50:51,920 --> 00:50:54,760
Speaker 1: hole collides with a nutron star, it generates a sphere

988
00:50:55,360 --> 00:50:58,080
Speaker 1: of of a ripple, right like it's propagating in all

989
00:50:58,120 --> 00:51:00,040
Speaker 1: directions at the same time. And you know, if a

990
00:51:00,200 --> 00:51:03,400
Speaker 1: billions of light years away from the source, then literally

991
00:51:03,440 --> 00:51:07,280
Speaker 1: the size of that sphere is billions of light years wide,

992
00:51:07,719 --> 00:51:09,760
Speaker 1: whereas a black hole is really just like a tiny

993
00:51:09,800 --> 00:51:12,319
Speaker 1: little blip that it passes through, you know, sort of

994
00:51:12,320 --> 00:51:14,319
Speaker 1: like if you dig a hole in the sand at

995
00:51:14,320 --> 00:51:17,920
Speaker 1: the beach and the huge long wave passes through, Like

996
00:51:18,000 --> 00:51:19,239
Speaker 1: you know, some of the waves is going to fall

997
00:51:19,239 --> 00:51:20,880
Speaker 1: into the hole, but the rest of the way it's

998
00:51:20,920 --> 00:51:23,239
Speaker 1: just gonna keep going as if nothing happened, right, Yeah,

999
00:51:23,320 --> 00:51:26,400
Speaker 1: that's true. Gravitational waves are bigger than black holes, and

1000
00:51:26,440 --> 00:51:29,640
Speaker 1: so some part of them will survive. Part that hits

1001
00:51:29,640 --> 00:51:32,000
Speaker 1: the black hole it's gone, but the rest of it

1002
00:51:32,080 --> 00:51:34,759
Speaker 1: will wiggle on through the universe. Yeah that's true. Yeah,

1003
00:51:34,760 --> 00:51:37,120
Speaker 1: And in fact, the black hole might even sort of

1004
00:51:37,120 --> 00:51:40,520
Speaker 1: feel insignificant to that gravitational wave. Right, It's like, oh,

1005
00:51:40,560 --> 00:51:42,880
Speaker 1: here's a little holes, I'll just step over it. It

1006
00:51:42,920 --> 00:51:45,359
Speaker 1: really is about the friends that the gravitational wave made

1007
00:51:45,400 --> 00:51:47,719
Speaker 1: along the way, right, right, But do you know what

1008
00:51:47,760 --> 00:51:49,600
Speaker 1: I mean, Like it's just as little blip. It's like

1009
00:51:49,600 --> 00:51:52,920
Speaker 1: putting a little obstacle in a huge long, you know break,

1010
00:51:53,400 --> 00:51:54,959
Speaker 1: you know, you know at the beach and the wave,

1011
00:51:55,200 --> 00:51:57,239
Speaker 1: and in fact at the beach that when the wave

1012
00:51:57,320 --> 00:52:01,120
Speaker 1: goes through an obstacle, it's sort of almost reforms itself

1013
00:52:01,200 --> 00:52:03,719
Speaker 1: after the obstacle. The same thing happened here with the

1014
00:52:03,719 --> 00:52:06,120
Speaker 1: black hole. Like with the wave that's me that immediately

1015
00:52:06,200 --> 00:52:08,200
Speaker 1: hits the black hole will get sucked in, But will

1016
00:52:08,239 --> 00:52:10,359
Speaker 1: the rest of the you know, waves sort of like

1017
00:52:10,560 --> 00:52:13,319
Speaker 1: patch up that hole eventually? Yeah. Absolutely. As the wave

1018
00:52:13,360 --> 00:52:16,200
Speaker 1: passes by the black hole, then the bits of the

1019
00:52:16,200 --> 00:52:19,560
Speaker 1: gravitational wave that are like just barely making it passed.

1020
00:52:19,840 --> 00:52:22,640
Speaker 1: They will continue to disperse, so eventually they will fan

1021
00:52:22,719 --> 00:52:24,799
Speaker 1: out and sort of fill in that gap. It will

1022
00:52:24,840 --> 00:52:27,800
Speaker 1: be totally unaffected. You could tell that that had happened.

1023
00:52:27,880 --> 00:52:30,359
Speaker 1: You will see lensing effects on the gravitational wave from

1024
00:52:30,400 --> 00:52:32,799
Speaker 1: the black hole. But yeah, there is no way that

1025
00:52:32,920 --> 00:52:36,440
Speaker 1: one black hole can completely squash a gravitational wave. So

1026
00:52:36,560 --> 00:52:39,600
Speaker 1: if you imagine, for example, a billion Superman's all running

1027
00:52:39,600 --> 00:52:41,960
Speaker 1: out in different directions, then the Hulk can only stop

1028
00:52:42,040 --> 00:52:44,240
Speaker 1: one of them. From that point of view, the billion

1029
00:52:44,280 --> 00:52:48,239
Speaker 1: Superman win. The infinite sequels of Superman beats out the

1030
00:52:48,680 --> 00:52:51,920
Speaker 1: one movie of the whole gave for me. Yeah, exactly,

1031
00:52:52,080 --> 00:52:54,240
Speaker 1: all right, so it's sort of a toss up, I guess,

1032
00:52:54,280 --> 00:52:56,840
Speaker 1: you know, like at the local level, a black hole

1033
00:52:56,920 --> 00:53:00,200
Speaker 1: will win over the gravitational wave. But in the long term,

1034
00:53:00,239 --> 00:53:02,480
Speaker 1: you know, the gravitational wave is going to have a better,

1035
00:53:02,640 --> 00:53:05,759
Speaker 1: better life, don't They say? That's the best revenge to

1036
00:53:05,840 --> 00:53:10,000
Speaker 1: have a good life. And remember that the universe is

1037
00:53:10,080 --> 00:53:14,040
Speaker 1: filled with these gravitational waves. They're passing through you right now,

1038
00:53:14,120 --> 00:53:16,960
Speaker 1: even if you're not the Hulk, Even if you're not Superman.

1039
00:53:17,080 --> 00:53:21,280
Speaker 1: You're getting squeezed and tugged by gravitational waves probably generated

1040
00:53:21,320 --> 00:53:25,359
Speaker 1: by ancient black holes gobbling each other billions of years ago.

1041
00:53:25,440 --> 00:53:28,360
Speaker 1: It's everywhere. We have a whole episode about the cosmic

1042
00:53:28,560 --> 00:53:32,160
Speaker 1: gravitational background, if you'd like to learn more about efforts

1043
00:53:32,200 --> 00:53:37,319
Speaker 1: to discover and measure these very gentle gravitational waves. Yeah,

1044
00:53:37,360 --> 00:53:39,800
Speaker 1: and even though you're the size that you are compared

1045
00:53:39,840 --> 00:53:43,480
Speaker 1: to a giant black hole, you still affect that gravitational wave. Right.

1046
00:53:43,480 --> 00:53:45,880
Speaker 1: It's passing through you, but you are sort of absorbing

1047
00:53:45,920 --> 00:53:47,920
Speaker 1: a little bit of it each time. Right. Part of

1048
00:53:47,960 --> 00:53:50,279
Speaker 1: the energy you have for your life today comes from

1049
00:53:50,280 --> 00:53:53,320
Speaker 1: those gravitational waves. Well, I just have one more question, Daniel.

1050
00:53:53,480 --> 00:53:55,640
Speaker 1: If I'm at the surface of a black hole and

1051
00:53:55,719 --> 00:53:58,200
Speaker 1: I slip on a banana peal, do I still generate

1052
00:53:58,239 --> 00:54:01,520
Speaker 1: a gravitational wave? You do? And then the black hole

1053
00:54:01,600 --> 00:54:05,160
Speaker 1: eats it? And you exactly, you eat it when you

1054
00:54:05,160 --> 00:54:07,560
Speaker 1: slip on the banana, and then the black hole eats

1055
00:54:07,560 --> 00:54:11,759
Speaker 1: your waves. Lots of eating here in the universe. Time

1056
00:54:11,800 --> 00:54:13,719
Speaker 1: to take a break for lunch, all right, Well, we

1057
00:54:13,840 --> 00:54:16,080
Speaker 1: hope you enjoyed that and maybe made you think a

1058
00:54:16,120 --> 00:54:17,960
Speaker 1: little bit about all of the amazing things that are

1059
00:54:17,960 --> 00:54:21,080
Speaker 1: happening out there right now. There are gravitation waves hitting

1060
00:54:21,080 --> 00:54:23,920
Speaker 1: black holes and black holes crashing into each other and

1061
00:54:23,960 --> 00:54:27,279
Speaker 1: making gravitation a wave. It's a pretty busy universe, it is,

1062
00:54:27,360 --> 00:54:30,080
Speaker 1: and those black holes continue to hide all of the

1063
00:54:30,200 --> 00:54:32,960
Speaker 1: plot holes from us. We can't even figure out what's

1064
00:54:32,960 --> 00:54:36,120
Speaker 1: going on, and they're by passing gravitational waves through them.

1065
00:54:36,160 --> 00:54:38,920
Speaker 1: If gravitational waves did pass through black holes, then they

1066
00:54:38,960 --> 00:54:41,319
Speaker 1: would be affected by what's inside and we can use

1067
00:54:41,360 --> 00:54:44,279
Speaker 1: that as a way to see inside those black hole

1068
00:54:44,320 --> 00:54:49,080
Speaker 1: event horizons. But unfortunately we can't, and they remain black. Oh,

1069
00:54:49,360 --> 00:54:53,200
Speaker 1: Daniel getting mad, you're turning green or red. I'm just

1070
00:54:53,280 --> 00:54:57,040
Speaker 1: frustrated by our inability to see the cosmic secrets hidden

1071
00:54:57,040 --> 00:54:59,560
Speaker 1: inside black holes. Well, you can always ask the billion

1072
00:54:59,600 --> 00:55:02,560
Speaker 1: superman in stud that are out there for future humanity.

1073
00:55:02,680 --> 00:55:05,239
Speaker 1: All right, Well, thanks for joining us, see you next time.

1074
00:55:13,120 --> 00:55:15,920
Speaker 1: Thanks for listening, and remember that Daniel and Jorge Explain

1075
00:55:16,000 --> 00:55:18,840
Speaker 1: the Universe is a production of I Heart Radio. For

1076
00:55:19,000 --> 00:55:21,919
Speaker 1: more podcast from my Heart Radio, visit the I Heart

1077
00:55:22,040 --> 00:55:25,600
Speaker 1: Radio app, Apple Podcasts, or wherever you listen to your

1078
00:55:25,680 --> 00:55:32,160
Speaker 1: favorite shows. Yeah,