1 00:00:00,000 --> 00:00:03,200 Okay, so picture this. 2 00:00:03,200 --> 00:00:04,040 Yeah. 3 00:00:04,040 --> 00:00:06,160 You're standing on a perfectly still lake 4 00:00:06,160 --> 00:00:09,440 and suddenly a pebble plunges into the water. 5 00:00:09,440 --> 00:00:10,280 Right. 6 00:00:10,280 --> 00:00:11,800 Sending ripples spreading outwards. 7 00:00:11,800 --> 00:00:12,640 Okay. 8 00:00:12,640 --> 00:00:16,540 Now imagine those ripples aren't in water 9 00:00:16,540 --> 00:00:19,940 but in the very fabric of space time itself. 10 00:00:20,920 --> 00:00:22,560 Created not by a pebble 11 00:00:22,560 --> 00:00:25,240 but by the collision of monstrous black holes 12 00:00:26,640 --> 00:00:28,040 billions of years ago. 13 00:00:28,040 --> 00:00:28,860 Wow. 14 00:00:28,860 --> 00:00:30,640 Those are gravitational waves. 15 00:00:30,640 --> 00:00:31,480 Yeah. 16 00:00:31,480 --> 00:00:33,320 Ripples in space time traveling at the speed of light. 17 00:00:33,320 --> 00:00:34,140 Right. 18 00:00:34,140 --> 00:00:36,440 And carrying whispers of some of the most powerful 19 00:00:36,440 --> 00:00:37,400 events in the universe. 20 00:00:37,400 --> 00:00:38,560 Really, it's incredible. 21 00:00:38,560 --> 00:00:39,720 It's like the universe has been playing 22 00:00:39,720 --> 00:00:41,840 a silent symphony for eons. 23 00:00:41,840 --> 00:00:43,160 We've only just started to listen. 24 00:00:43,160 --> 00:00:44,360 Yeah. 25 00:00:44,360 --> 00:00:47,040 Welcome to Cosmos in a Pod, Space and Astronomy series. 26 00:00:47,040 --> 00:00:49,160 Today we're diving deep into the world 27 00:00:49,160 --> 00:00:50,480 of gravitational waves. 28 00:00:50,480 --> 00:00:51,320 Okay. 29 00:00:51,320 --> 00:00:53,680 What they are, how they form, 30 00:00:53,680 --> 00:00:54,920 how we detect them, 31 00:00:54,920 --> 00:00:56,480 and what they can tell us about the universe. 32 00:00:56,480 --> 00:00:57,300 Sounds good. 33 00:00:57,300 --> 00:00:58,440 So these gravitational waves, 34 00:00:58,440 --> 00:01:01,400 they're literally ripples in the fabric of space time. 35 00:01:01,400 --> 00:01:03,920 Yeah, it's pretty mind bending, right? 36 00:01:03,920 --> 00:01:04,880 Yeah. 37 00:01:04,880 --> 00:01:06,280 Can you break that down for me a bit? 38 00:01:06,280 --> 00:01:07,120 Yeah. 39 00:01:07,120 --> 00:01:10,040 What does it even mean for space time to ripple? 40 00:01:10,040 --> 00:01:13,280 Well, think of space time as the very fabric 41 00:01:13,280 --> 00:01:14,100 of the universe. 42 00:01:14,100 --> 00:01:17,520 The stage on which all cosmic events play out. 43 00:01:17,520 --> 00:01:20,960 According to Einstein's theory of general relativity, 44 00:01:20,960 --> 00:01:25,960 massive objects like stars and planets 45 00:01:26,200 --> 00:01:27,920 actually warp this fabric, 46 00:01:27,920 --> 00:01:29,520 creating a sort of dent. 47 00:01:29,520 --> 00:01:30,360 Okay. 48 00:01:30,360 --> 00:01:31,680 And when those objects accelerate, 49 00:01:31,680 --> 00:01:34,800 like when two black holes spiral toward each other 50 00:01:34,800 --> 00:01:36,440 and eventually collide, 51 00:01:36,440 --> 00:01:39,680 those dents become waves that propagate outwards, 52 00:01:39,680 --> 00:01:41,000 like ripples on a pond. 53 00:01:41,000 --> 00:01:42,640 Okay, so I'm starting to get the picture. 54 00:01:42,640 --> 00:01:43,480 Good. 55 00:01:43,480 --> 00:01:45,440 But what kinds of events are powerful enough 56 00:01:45,440 --> 00:01:47,080 to create these ripples in space time? 57 00:01:47,080 --> 00:01:47,900 Yeah. 58 00:01:47,900 --> 00:01:49,480 You mentioned black holes colliding, 59 00:01:49,480 --> 00:01:52,360 but are there other sources of gravitational waves? 60 00:01:52,360 --> 00:01:53,380 Oh, absolutely. 61 00:01:53,380 --> 00:01:54,960 Black hole mergers are definitely 62 00:01:54,960 --> 00:01:56,720 some of the most dramatic sources, 63 00:01:56,720 --> 00:01:58,000 but there are others. 64 00:01:58,000 --> 00:01:58,840 Yeah. 65 00:01:58,840 --> 00:02:00,400 For example, when massive stars die 66 00:02:00,400 --> 00:02:03,280 in spectacular supernova explosions, 67 00:02:03,280 --> 00:02:05,400 they can also generate gravitational waves. 68 00:02:05,400 --> 00:02:06,240 Okay. 69 00:02:06,240 --> 00:02:08,040 And when two neutron stars, 70 00:02:08,040 --> 00:02:12,080 those incredibly dense remnants of collapsed stars 71 00:02:12,080 --> 00:02:14,520 spiral towards each other and collide. 72 00:02:14,520 --> 00:02:15,360 Wow. 73 00:02:15,360 --> 00:02:18,020 The resulting cataclysm sends powerful ripples 74 00:02:18,020 --> 00:02:19,260 through space time. 75 00:02:19,260 --> 00:02:21,180 Neutron star collisions. 76 00:02:21,180 --> 00:02:24,120 Those sound pretty intense. 77 00:02:24,120 --> 00:02:24,960 Yeah. 78 00:02:24,960 --> 00:02:26,640 I mean, what happens when two objects 79 00:02:26,640 --> 00:02:28,200 in the dense smash into each other? 80 00:02:28,200 --> 00:02:30,600 Well, it's one of the most violent events in the universe. 81 00:02:30,600 --> 00:02:31,440 Really? 82 00:02:31,440 --> 00:02:33,680 Not only do they create gravitational waves, 83 00:02:33,680 --> 00:02:38,120 but they also unleash bursts of electromagnetic radiation 84 00:02:38,120 --> 00:02:42,040 across the spectrum, from gamma rays to radio waves. 85 00:02:42,040 --> 00:02:42,880 Wow. 86 00:02:42,880 --> 00:02:44,560 It's a cosmic light show, 87 00:02:44,560 --> 00:02:47,080 accompanied by a symphony of gravitational waves. 88 00:02:47,080 --> 00:02:47,920 Yeah. 89 00:02:47,920 --> 00:02:49,480 And it's in these collisions that many 90 00:02:49,480 --> 00:02:52,040 of the heavier elements in the universe are forged, 91 00:02:52,040 --> 00:02:53,800 including gold and platinum. 92 00:02:53,800 --> 00:02:55,480 Wait, so the gold in my wedding ring 93 00:02:55,480 --> 00:02:58,360 was actually created in a neutron star collision 94 00:02:58,360 --> 00:02:59,520 billions of years ago. 95 00:02:59,520 --> 00:03:00,520 It is, isn't it? 96 00:03:00,520 --> 00:03:01,440 That's amazing. 97 00:03:01,440 --> 00:03:02,500 It gives a whole new meaning 98 00:03:02,500 --> 00:03:04,280 to the phrase cosmic connection. 99 00:03:04,280 --> 00:03:05,120 Yeah. 100 00:03:05,120 --> 00:03:05,960 And these are just a few examples. 101 00:03:05,960 --> 00:03:06,800 Okay. 102 00:03:06,800 --> 00:03:08,880 There are other potential sources of gravitational waves, 103 00:03:08,880 --> 00:03:12,160 like pulsars, rapidly spinning neutron stars. 104 00:03:12,160 --> 00:03:13,000 Yeah. 105 00:03:13,000 --> 00:03:14,640 And even the Big Bang itself would have created 106 00:03:14,640 --> 00:03:17,860 a background hum of gravitational waves. 107 00:03:17,860 --> 00:03:20,520 If we could detect those primordial waves, 108 00:03:20,520 --> 00:03:21,640 it would be like listening 109 00:03:21,640 --> 00:03:24,120 to the echo of the universe's birth. 110 00:03:24,120 --> 00:03:25,120 Wow. 111 00:03:25,120 --> 00:03:27,360 So we've got all these incredible events happening 112 00:03:27,360 --> 00:03:28,200 in the universe. 113 00:03:28,200 --> 00:03:29,040 Yeah. 114 00:03:29,040 --> 00:03:30,760 Taking space time and sending out these ripples. 115 00:03:30,760 --> 00:03:31,600 Uh-huh. 116 00:03:31,600 --> 00:03:33,440 But if they're so faint, 117 00:03:33,440 --> 00:03:35,480 how in the world do we even detect them? 118 00:03:35,480 --> 00:03:37,120 Right, that's the question. 119 00:03:37,120 --> 00:03:39,280 I mean, we're talking about measuring changes 120 00:03:39,280 --> 00:03:41,360 smaller than a fraction of an atom's width, right? 121 00:03:41,360 --> 00:03:42,200 So. Right. 122 00:03:42,200 --> 00:03:44,680 It's a truly remarkable feat of engineering 123 00:03:44,680 --> 00:03:46,400 and scientific ingenuity. 124 00:03:46,400 --> 00:03:47,240 Yeah. 125 00:03:47,240 --> 00:03:50,280 The instruments we use to detect these minute changes 126 00:03:50,280 --> 00:03:52,640 are called laser interferometers. 127 00:03:52,640 --> 00:03:53,480 Okay. 128 00:03:53,480 --> 00:03:57,000 So the laser interferometer Gravitational Wave Observatory 129 00:03:57,000 --> 00:03:58,400 is the most famous example. 130 00:03:58,400 --> 00:03:59,240 Right. 131 00:03:59,240 --> 00:04:01,560 It uses lasers and mirrors to measure the stretching 132 00:04:01,560 --> 00:04:02,960 and compressing of space. 133 00:04:02,960 --> 00:04:03,800 Right. 134 00:04:03,800 --> 00:04:05,480 Caused by passing gravitational waves. 135 00:04:05,480 --> 00:04:06,640 So how does that work? 136 00:04:06,640 --> 00:04:07,480 Well. 137 00:04:07,480 --> 00:04:08,940 I mean, how can a laser measure something 138 00:04:08,940 --> 00:04:10,880 as subtle as a ripple in space time? 139 00:04:10,880 --> 00:04:14,680 Imagine a giant L shape with arms that are kilometers long. 140 00:04:14,680 --> 00:04:15,520 Okay. 141 00:04:15,520 --> 00:04:18,760 At the end of each arm is a highly polished mirror. 142 00:04:18,760 --> 00:04:19,600 Right. 143 00:04:19,600 --> 00:04:21,720 Lasers are constantly bouncing back and forth 144 00:04:21,720 --> 00:04:22,800 between these mirrors. 145 00:04:22,800 --> 00:04:23,640 Mm-hmm. 146 00:04:23,640 --> 00:04:26,000 When a gravitational wave passes through, 147 00:04:26,000 --> 00:04:29,840 it stretches one arm of the L while compressing the other. 148 00:04:29,840 --> 00:04:30,660 Oh. 149 00:04:30,660 --> 00:04:33,920 The lasers pick up this tiny difference in distance. 150 00:04:33,920 --> 00:04:34,760 Uh-huh. 151 00:04:34,760 --> 00:04:35,960 And that's how we detect the wave. 152 00:04:35,960 --> 00:04:39,640 So it's like the laser is acting as a super sensitive ruler 153 00:04:39,640 --> 00:04:42,040 measuring the changing distance between the mirrors. 154 00:04:42,040 --> 00:04:43,040 That's a great way to put it. 155 00:04:43,040 --> 00:04:43,880 Okay. 156 00:04:43,880 --> 00:04:44,720 And it's not just Lego. 157 00:04:44,720 --> 00:04:45,540 Right. 158 00:04:45,540 --> 00:04:46,840 There are other gravitational wave detectors 159 00:04:46,840 --> 00:04:47,680 around the world. 160 00:04:47,680 --> 00:04:48,500 Yeah. 161 00:04:48,500 --> 00:04:49,340 Like Virgo in Italy. 162 00:04:49,340 --> 00:04:50,180 Mm-hmm. 163 00:04:50,180 --> 00:04:52,040 And K.A. Ra in Japan. 164 00:04:52,040 --> 00:04:52,880 Okay. 165 00:04:52,880 --> 00:04:55,160 By working together, these observatories 166 00:04:55,160 --> 00:04:58,160 can pinpoint the location of gravitational wave sources 167 00:04:58,160 --> 00:04:59,240 in the sky. 168 00:04:59,240 --> 00:05:00,080 Mm-hmm. 169 00:05:00,080 --> 00:05:02,200 And gather even more data about these events. 170 00:05:02,200 --> 00:05:03,640 Wow, this is just incredible. 171 00:05:03,640 --> 00:05:06,300 I'm starting to see why this is such a groundbreaking field. 172 00:05:06,300 --> 00:05:07,140 It really is. 173 00:05:07,140 --> 00:05:10,080 It's like we've suddenly been given a new sense, 174 00:05:10,080 --> 00:05:12,960 a new way to perceive the universe, 175 00:05:12,960 --> 00:05:14,600 beyond just light and other forms 176 00:05:14,600 --> 00:05:16,080 of electromagnetic radiation. 177 00:05:16,080 --> 00:05:16,920 Yeah. 178 00:05:16,920 --> 00:05:18,680 And with each detection, we're learning more 179 00:05:18,680 --> 00:05:21,680 about the most extreme environments in the cosmos. 180 00:05:21,680 --> 00:05:23,960 Speaking of which, let's talk about 181 00:05:23,960 --> 00:05:26,680 what we can actually learn from these gravitational waves. 182 00:05:26,680 --> 00:05:27,520 Okay. 183 00:05:27,520 --> 00:05:29,280 What kind of information are they carrying 184 00:05:29,280 --> 00:05:33,120 about these mind-boggling events? 185 00:05:33,120 --> 00:05:35,220 Well, first of all, gravitational waves allow us 186 00:05:35,220 --> 00:05:38,680 to see events that are otherwise invisible 187 00:05:38,680 --> 00:05:40,640 to traditional telescopes. 188 00:05:40,640 --> 00:05:42,560 Like the mergers of black holes. 189 00:05:42,560 --> 00:05:43,380 Right. 190 00:05:43,380 --> 00:05:45,560 These are objects so dense that not even light 191 00:05:45,560 --> 00:05:48,040 can escape their gravitational pull. 192 00:05:48,040 --> 00:05:48,880 Okay. 193 00:05:48,880 --> 00:05:49,800 But with gravitational waves, 194 00:05:49,800 --> 00:05:53,720 we can hear these collisions, these cosmic dances, 195 00:05:53,720 --> 00:05:55,320 revealing their secrets. 196 00:05:55,320 --> 00:05:56,160 That's fascinating. 197 00:05:56,160 --> 00:05:59,160 We're getting a glimpse into regions of the universe 198 00:05:59,160 --> 00:06:01,160 that were previously hidden from our view. 199 00:06:01,160 --> 00:06:02,000 Right. 200 00:06:02,000 --> 00:06:02,820 What else can we learn? 201 00:06:02,820 --> 00:06:04,440 Well, for example, by analyzing 202 00:06:04,440 --> 00:06:06,360 the gravitational wave signal, 203 00:06:06,360 --> 00:06:08,580 we can determine the masses of the black holes 204 00:06:08,580 --> 00:06:10,960 that collided, their distance from Earth, 205 00:06:10,960 --> 00:06:14,300 their spins, and even the orientation of other orbits. 206 00:06:14,300 --> 00:06:16,600 It's like we're reconstructing the crime scene, 207 00:06:16,600 --> 00:06:19,960 piecing together the details of this cosmic collision 208 00:06:19,960 --> 00:06:21,160 billions of years ago. 209 00:06:21,160 --> 00:06:24,840 So each gravitational wave is like a cosmic fingerprint, 210 00:06:24,840 --> 00:06:26,920 unique to the event that created it. 211 00:06:26,920 --> 00:06:28,280 That's a great analogy. 212 00:06:28,280 --> 00:06:30,200 And it's not just about black holes. 213 00:06:30,200 --> 00:06:31,040 Yeah. 214 00:06:31,040 --> 00:06:32,840 Remember those neutron star collisions we talked about? 215 00:06:32,840 --> 00:06:33,680 Yeah. 216 00:06:33,680 --> 00:06:35,320 Gravitational waves from those events 217 00:06:35,320 --> 00:06:38,240 can tell us about the properties of neutron stars. 218 00:06:38,240 --> 00:06:39,080 Right. 219 00:06:39,080 --> 00:06:41,720 Which are some of the densest objects in the universe. 220 00:06:41,720 --> 00:06:44,480 Okay, so we're learning about black holes, neutron stars. 221 00:06:44,480 --> 00:06:45,320 Yeah. 222 00:06:45,320 --> 00:06:47,760 And what about the bigger picture? 223 00:06:47,760 --> 00:06:49,880 Can gravitational waves tell us anything 224 00:06:49,880 --> 00:06:52,200 about the universe as a whole? 225 00:06:52,200 --> 00:06:53,300 Absolutely. 226 00:06:53,300 --> 00:06:55,360 For example, we can use gravitational waves 227 00:06:55,360 --> 00:06:57,200 to measure cosmic distances. 228 00:06:57,200 --> 00:06:58,040 Okay. 229 00:06:58,040 --> 00:06:59,380 Which helps us refine our understanding 230 00:06:59,380 --> 00:07:02,000 of the universe's expansion and evolution. 231 00:07:02,000 --> 00:07:02,840 Right. 232 00:07:02,840 --> 00:07:04,960 And remember those primordial 233 00:07:04,960 --> 00:07:07,040 gravitational waves from the Big Bang? 234 00:07:07,040 --> 00:07:07,880 Yeah. 235 00:07:07,880 --> 00:07:09,640 If we could detect those, it would be like 236 00:07:09,640 --> 00:07:13,440 looking back in time to the very beginning of the universe, 237 00:07:13,440 --> 00:07:16,560 revealing secrets about its earliest moments. 238 00:07:16,560 --> 00:07:18,100 Wow. 239 00:07:18,100 --> 00:07:20,200 It sounds like gravitational wave astronomy 240 00:07:20,200 --> 00:07:23,320 has the potential to revolutionize 241 00:07:23,320 --> 00:07:25,040 our understanding of the cosmos. 242 00:07:25,040 --> 00:07:26,000 It really does. 243 00:07:26,000 --> 00:07:26,820 Okay. 244 00:07:26,820 --> 00:07:27,880 And this is just the beginning. 245 00:07:27,880 --> 00:07:28,720 Right. 246 00:07:28,720 --> 00:07:30,360 As our technology improves, 247 00:07:30,360 --> 00:07:33,840 we'll be able to detect even fainter gravitational waves, 248 00:07:33,840 --> 00:07:36,480 revealing even more secrets about the universe. 249 00:07:36,480 --> 00:07:38,080 I'm already hooked. 250 00:07:38,080 --> 00:07:40,240 But before we dive into the future of this field, 251 00:07:40,240 --> 00:07:41,080 Yeah. 252 00:07:41,080 --> 00:07:42,320 I wanna go back to the basics for a moment. 253 00:07:42,320 --> 00:07:43,160 Okay. 254 00:07:43,160 --> 00:07:45,040 So can you explain in a bit more detail 255 00:07:45,040 --> 00:07:47,440 how gravitational waves actually work? 256 00:07:47,440 --> 00:07:48,880 What makes them a wave? 257 00:07:48,880 --> 00:07:49,800 Sure. 258 00:07:49,800 --> 00:07:52,840 Gravitational waves are transverse waves, 259 00:07:52,840 --> 00:07:55,780 which means that they stretch and compress space-time 260 00:07:55,780 --> 00:07:59,400 in directions perpendicular to their direction of travel. 261 00:07:59,400 --> 00:08:00,240 Okay. 262 00:08:00,240 --> 00:08:02,460 Think of a wave moving across the surface of water. 263 00:08:02,460 --> 00:08:03,300 Right. 264 00:08:03,300 --> 00:08:05,360 The water itself doesn't move forward with the wave, 265 00:08:05,360 --> 00:08:07,120 instead it moves up and down, 266 00:08:07,120 --> 00:08:09,600 perpendicular to the direction the wave is traveling. 267 00:08:09,600 --> 00:08:10,840 Okay, I'm picturing that. 268 00:08:10,840 --> 00:08:11,680 Good. 269 00:08:11,680 --> 00:08:14,600 So how do we actually measure this stretching 270 00:08:14,600 --> 00:08:16,240 and compressing of space-time? 271 00:08:16,240 --> 00:08:17,080 Right. 272 00:08:17,080 --> 00:08:18,160 It must be incredibly subtle. 273 00:08:18,160 --> 00:08:20,840 It is, and that's where those incredibly sensitive 274 00:08:20,840 --> 00:08:22,680 laser interferometers come in. 275 00:08:22,680 --> 00:08:23,520 Right. 276 00:08:23,520 --> 00:08:26,600 They're designed to measure this strain, that is, 277 00:08:26,600 --> 00:08:30,120 the amount of stretching or compressing caused by the wave. 278 00:08:30,120 --> 00:08:32,760 Strain measurement, so it's essentially 279 00:08:32,760 --> 00:08:35,240 how much space itself is distorted 280 00:08:35,240 --> 00:08:36,680 by the passing gravitational wave? 281 00:08:36,680 --> 00:08:37,520 Exactly. 282 00:08:37,520 --> 00:08:38,340 Okay. 283 00:08:38,340 --> 00:08:39,700 And it's an incredibly small effect. 284 00:08:39,700 --> 00:08:40,540 Yeah. 285 00:08:40,540 --> 00:08:41,960 We're talking about changes in distance 286 00:08:41,960 --> 00:08:44,460 that are far smaller than the width of an atom. 287 00:08:44,460 --> 00:08:45,820 That's mind-boggling. 288 00:08:45,820 --> 00:08:46,660 Yeah. 289 00:08:46,660 --> 00:08:49,100 I can't even imagine trying to measure something that small. 290 00:08:49,100 --> 00:08:52,240 It's a testament to human ingenuity and persistence 291 00:08:52,240 --> 00:08:54,640 that we've managed to develop instruments 292 00:08:54,640 --> 00:08:57,140 capable of such incredible precision. 293 00:08:57,140 --> 00:08:58,980 So by measuring the strain, 294 00:08:58,980 --> 00:09:01,360 we can actually learn about the properties 295 00:09:01,360 --> 00:09:03,400 of the objects that created the waves. 296 00:09:03,400 --> 00:09:04,240 Precisely. 297 00:09:04,240 --> 00:09:05,080 Okay. 298 00:09:05,080 --> 00:09:06,820 For example, the amount of strain tells us about the mass 299 00:09:06,820 --> 00:09:08,880 of the objects involved in the event. 300 00:09:08,880 --> 00:09:09,720 Uh-huh. 301 00:09:09,720 --> 00:09:12,080 The mass, the stronger the gravitational waves. 302 00:09:12,080 --> 00:09:12,920 Right. 303 00:09:12,920 --> 00:09:13,740 And the greater the strain. 304 00:09:13,740 --> 00:09:15,720 Okay, I'm starting to see how this all fits together. 305 00:09:15,720 --> 00:09:17,600 We're essentially listening 306 00:09:17,600 --> 00:09:20,000 to the universe's gravitational symphony. 307 00:09:20,000 --> 00:09:20,920 Yes. 308 00:09:20,920 --> 00:09:24,120 And using those sounds to decipher the secrets 309 00:09:24,120 --> 00:09:26,720 of some of the most powerful events in the cosmos. 310 00:09:26,720 --> 00:09:28,260 That's a beautiful way to put it. 311 00:09:28,260 --> 00:09:30,820 And the information we can glean from these sounds 312 00:09:30,820 --> 00:09:32,760 is truly astounding. 313 00:09:32,760 --> 00:09:34,240 Yeah, that's amazing. 314 00:09:34,240 --> 00:09:38,440 For example, did you know that when two black holes collide, 315 00:09:38,440 --> 00:09:40,500 the energy released in gravitational waves 316 00:09:40,500 --> 00:09:42,720 can exceed the combined energy output 317 00:09:42,720 --> 00:09:45,720 of all the stars in the observable universe 318 00:09:45,720 --> 00:09:46,680 during the event? 319 00:09:46,680 --> 00:09:47,520 Whoa. 320 00:09:47,520 --> 00:09:48,360 Yeah. 321 00:09:48,360 --> 00:09:50,360 That's impossible to even wrap my head around. 322 00:09:50,360 --> 00:09:51,840 It really is mind-boggling. 323 00:09:51,840 --> 00:09:52,680 Yeah. 324 00:09:52,680 --> 00:09:54,040 But that's the beauty of gravitational wave astronomy. 325 00:09:54,040 --> 00:09:56,240 It's constantly challenging our understanding 326 00:09:56,240 --> 00:09:57,080 of the universe. 327 00:09:57,080 --> 00:09:57,920 Right. 328 00:09:57,920 --> 00:10:00,440 And pushing the boundaries of what we thought was possible. 329 00:10:00,440 --> 00:10:02,280 This has been absolutely fascinating. 330 00:10:02,280 --> 00:10:03,120 Yeah. 331 00:10:03,120 --> 00:10:05,660 I'm already eager to hear more about what the future holds 332 00:10:05,660 --> 00:10:07,200 for this incredible field. 333 00:10:07,200 --> 00:10:09,320 Well, get ready, because we're just getting started. 334 00:10:09,320 --> 00:10:11,240 The future of gravitational wave astronomy 335 00:10:11,240 --> 00:10:13,440 is incredibly exciting. 336 00:10:13,440 --> 00:10:13,760 Yeah. 337 00:10:13,760 --> 00:10:16,680 We're on the cusp of a new era of discovery. 338 00:10:16,680 --> 00:10:19,120 And it's only going to get more incredible from here. 339 00:10:19,120 --> 00:10:20,240 OK, all ears. 340 00:10:20,240 --> 00:10:21,080 OK. 341 00:10:21,080 --> 00:10:23,280 What kind of advancements are on the horizon? 342 00:10:23,280 --> 00:10:27,400 What are scientists working on that has you so excited? 343 00:10:27,400 --> 00:10:29,360 Well, for one thing, we're building even more 344 00:10:29,360 --> 00:10:31,360 sensitive detectors. 345 00:10:31,360 --> 00:10:34,640 Lysa, the laser interferometer space antenna, 346 00:10:34,640 --> 00:10:37,880 will be a space-based observatory, 347 00:10:37,880 --> 00:10:40,760 free from the limitations of Earth-based detectors. 348 00:10:40,760 --> 00:10:41,680 Space-based? 349 00:10:41,680 --> 00:10:42,360 Yeah. 350 00:10:42,360 --> 00:10:43,960 Wow. 351 00:10:43,960 --> 00:10:45,760 That's taking things to a whole new level. 352 00:10:45,760 --> 00:10:46,520 It is. 353 00:10:46,520 --> 00:10:50,720 What will Lysa be able to detect that LIGO can't? 354 00:10:50,720 --> 00:10:55,680 Lysa will be sensitive to lower frequency gravitational waves, 355 00:10:55,680 --> 00:10:57,900 which means it'll be able to detect events involving 356 00:10:57,900 --> 00:11:00,800 even more massive objects, like the mergers 357 00:11:00,800 --> 00:11:04,160 of supermassive black holes at the centers of galaxies. 358 00:11:04,160 --> 00:11:07,520 Those events are too massive and too slow for LIGO to pick up. 359 00:11:07,520 --> 00:11:11,480 So we'll be able to witness the cosmic ballet of giants, 360 00:11:11,480 --> 00:11:14,400 black holes, millions or even billions of times 361 00:11:14,400 --> 00:11:17,200 the mass of our sun spiraling towards each other 362 00:11:17,200 --> 00:11:17,720 and colliding. 363 00:11:17,720 --> 00:11:18,720 Exactly. 364 00:11:18,720 --> 00:11:21,320 It'll be like opening another window onto the universe. 365 00:11:21,320 --> 00:11:25,640 Revealing a whole new realm of cosmic phenomena. 366 00:11:25,640 --> 00:11:27,440 And with each detection, we'll learn more 367 00:11:27,440 --> 00:11:30,840 about the evolution of galaxies, the formation 368 00:11:30,840 --> 00:11:33,200 of the large-scale structure of the universe, 369 00:11:33,200 --> 00:11:35,400 and the nature of gravity itself. 370 00:11:35,400 --> 00:11:37,160 I can see why you're excited. 371 00:11:37,160 --> 00:11:39,560 We're moving from listening to whispers 372 00:11:39,560 --> 00:11:42,080 to hearing the full roar of the universe. 373 00:11:42,080 --> 00:11:43,000 Yeah, it is. 374 00:11:43,000 --> 00:11:45,880 But it's not just about building bigger and better detectors, 375 00:11:45,880 --> 00:11:46,600 is it? 376 00:11:46,600 --> 00:11:49,480 What other breakthroughs are on the horizon? 377 00:11:49,480 --> 00:11:53,520 Another exciting development is multi-messenger astronomy, 378 00:11:53,520 --> 00:11:56,200 where we combine gravitational wave observations 379 00:11:56,200 --> 00:11:58,960 with observations from traditional telescopes that 380 00:11:58,960 --> 00:12:02,360 detect light, radio waves, x-rays, 381 00:12:02,360 --> 00:12:04,880 and other forms of electromagnetic radiation. 382 00:12:04,880 --> 00:12:06,760 So instead of just hearing the universe 383 00:12:06,760 --> 00:12:09,520 with gravitational waves, we'll be able to see it, too, 384 00:12:09,520 --> 00:12:12,320 getting a much more complete picture of these cosmic events. 385 00:12:12,320 --> 00:12:12,880 Exactly. 386 00:12:12,880 --> 00:12:15,320 Remember those neutron star collisions 387 00:12:15,320 --> 00:12:17,080 that create gold and platinum? 388 00:12:17,080 --> 00:12:19,600 Well, when those events happen, they not only 389 00:12:19,600 --> 00:12:21,520 emit gravitational waves, but they also 390 00:12:21,520 --> 00:12:24,960 produce a burst of light and other electromagnetic radiation. 391 00:12:24,960 --> 00:12:27,920 So by combining those observations, 392 00:12:27,920 --> 00:12:30,960 we could pinpoint the location of the collision. 393 00:12:30,960 --> 00:12:33,120 See the afterglow of the explosion 394 00:12:33,120 --> 00:12:37,480 and analyze the light to learn even more about the processes 395 00:12:37,480 --> 00:12:39,120 that created those heavy elements. 396 00:12:39,120 --> 00:12:40,440 Precisely. 397 00:12:40,440 --> 00:12:42,320 It's like having multiple witnesses 398 00:12:42,320 --> 00:12:45,160 to a cosmic crime scene, each providing 399 00:12:45,160 --> 00:12:47,160 a different piece of the puzzle. 400 00:12:47,160 --> 00:12:49,600 And by putting those pieces together, 401 00:12:49,600 --> 00:12:53,320 we can build a much richer and more nuanced understanding 402 00:12:53,320 --> 00:12:55,160 of these incredible events. 403 00:12:55,160 --> 00:12:57,600 It's like we're moving from black and white silent films 404 00:12:57,600 --> 00:13:00,120 to full color IMAX movies of the universe. 405 00:13:00,120 --> 00:13:01,240 Exactly. 406 00:13:01,240 --> 00:13:03,040 But with all these new discoveries, 407 00:13:03,040 --> 00:13:06,600 there must still be some big questions that are keeping 408 00:13:06,600 --> 00:13:08,520 scientists up at night. 409 00:13:08,520 --> 00:13:11,320 What are the big mysteries that gravitational wave astronomy 410 00:13:11,320 --> 00:13:12,480 is still trying to solve? 411 00:13:12,480 --> 00:13:13,880 Oh, there are plenty. 412 00:13:13,880 --> 00:13:15,600 One of the biggest ones is the nature 413 00:13:15,600 --> 00:13:17,480 of black hole singularities. 414 00:13:17,480 --> 00:13:20,120 These are the points at the center of black holes, 415 00:13:20,120 --> 00:13:22,660 where according to our current understanding of physics, 416 00:13:22,660 --> 00:13:25,160 density and gravity become infinite. 417 00:13:25,160 --> 00:13:27,920 It's a region where our current laws of physics break down. 418 00:13:27,920 --> 00:13:30,480 So basically a point where everything 419 00:13:30,480 --> 00:13:33,000 we know about the universe goes haywire. 420 00:13:33,000 --> 00:13:33,800 Pretty much. 421 00:13:33,800 --> 00:13:37,120 We don't really know what happens at a singularity. 422 00:13:37,120 --> 00:13:39,560 Do the laws of physics, as we know them, still apply? 423 00:13:39,560 --> 00:13:41,640 Do they break down completely? 424 00:13:41,640 --> 00:13:43,840 Are there new laws of physics that we haven't even 425 00:13:43,840 --> 00:13:47,600 discovered yet that govern these extreme environments? 426 00:13:47,600 --> 00:13:49,680 It's like staring into the abyss of the unknown. 427 00:13:49,680 --> 00:13:50,360 Exactly. 428 00:13:50,360 --> 00:13:52,600 And that's what makes it so fascinating. 429 00:13:52,600 --> 00:13:54,960 Gravitational waves might provide clues 430 00:13:54,960 --> 00:13:58,480 to help us understand these enigmatic singularities. 431 00:13:58,480 --> 00:14:00,400 They might also help us unlock secrets 432 00:14:00,400 --> 00:14:02,760 about the very first moments of the universe. 433 00:14:02,760 --> 00:14:05,200 You're talking about those primordial gravitational waves 434 00:14:05,200 --> 00:14:06,000 from the Big Bang? 435 00:14:06,000 --> 00:14:07,320 Yes. 436 00:14:07,320 --> 00:14:08,880 If we could detect them, it would 437 00:14:08,880 --> 00:14:11,840 be like listening to the echo of the universe's birth. 438 00:14:11,840 --> 00:14:12,840 Wow. 439 00:14:12,840 --> 00:14:15,040 A signal from a time when the universe was just 440 00:14:15,040 --> 00:14:16,480 a fraction of a second old. 441 00:14:16,480 --> 00:14:17,640 That's amazing. 442 00:14:17,640 --> 00:14:19,560 Imagine the secrets those waves could tell us 443 00:14:19,560 --> 00:14:23,480 about the origins of everything we see around us. 444 00:14:23,480 --> 00:14:25,880 It's mind blowing to think that we might one day 445 00:14:25,880 --> 00:14:29,200 be able to listen to the very first tremors of the universe. 446 00:14:29,200 --> 00:14:30,720 What other mysteries are out there? 447 00:14:30,720 --> 00:14:33,040 Well, on a more practical level, we're 448 00:14:33,040 --> 00:14:35,440 still trying to understand how often 449 00:14:35,440 --> 00:14:38,960 black hole and neutron star mergers actually happen. 450 00:14:38,960 --> 00:14:41,640 We've detected a handful of events so far. 451 00:14:41,640 --> 00:14:43,640 But that's just a tiny fraction of what's 452 00:14:43,640 --> 00:14:46,200 likely happening out there in the vastness of space. 453 00:14:46,200 --> 00:14:48,120 So it's not just about detecting these events. 454 00:14:48,120 --> 00:14:52,040 It's about understanding their frequency and distribution 455 00:14:52,040 --> 00:14:53,000 throughout the universe. 456 00:14:53,000 --> 00:14:53,560 Exactly. 457 00:14:53,560 --> 00:14:54,320 OK. 458 00:14:54,320 --> 00:14:56,560 Knowing how often these mergers occur 459 00:14:56,560 --> 00:14:59,920 is crucial for building accurate models of the universe's 460 00:14:59,920 --> 00:15:01,080 evolution. 461 00:15:01,080 --> 00:15:04,360 It can also help us understand the formation and distribution 462 00:15:04,360 --> 00:15:07,360 of heavy elements like gold and platinum. 463 00:15:07,360 --> 00:15:10,760 So even with all the incredible discoveries we've made so far, 464 00:15:10,760 --> 00:15:13,040 we're still just scratching the surface 465 00:15:13,040 --> 00:15:15,600 of what gravitational wave astronomy can teach us. 466 00:15:15,600 --> 00:15:16,560 Absolutely. 467 00:15:16,560 --> 00:15:18,960 It's a young field, but it's already 468 00:15:18,960 --> 00:15:21,720 revolutionizing our understanding of the universe. 469 00:15:21,720 --> 00:15:23,680 And with each new discovery, we're 470 00:15:23,680 --> 00:15:27,240 realizing just how much more there is to learn. 471 00:15:27,240 --> 00:15:29,840 I have to admit, I'm a little bit lost on how we actually 472 00:15:29,840 --> 00:15:32,000 extract all this information from these waves. 473 00:15:32,000 --> 00:15:35,280 How do we go from measuring a tiny wobble in a mirror 474 00:15:35,280 --> 00:15:38,680 to understanding the properties of a black hole billions 475 00:15:38,680 --> 00:15:40,080 of light years away? 476 00:15:40,080 --> 00:15:43,520 It's a complex process, but here's the basic idea. 477 00:15:43,520 --> 00:15:47,200 When a gravitational wave passes through LIGO, 478 00:15:47,200 --> 00:15:49,680 it stretches one arm of the interferometer 479 00:15:49,680 --> 00:15:51,040 while compressing the other. 480 00:15:51,040 --> 00:15:51,600 Right. 481 00:15:51,600 --> 00:15:54,400 The lasers bouncing back and forth between the mirrors 482 00:15:54,400 --> 00:15:56,920 pick up this tiny difference in length. 483 00:15:56,920 --> 00:15:58,920 And that signal is what we analyze. 484 00:15:58,920 --> 00:16:01,560 So the pattern of stretching and compressing, that's the key. 485 00:16:01,560 --> 00:16:02,640 Exactly. 486 00:16:02,640 --> 00:16:05,160 That pattern, known as the waveform, 487 00:16:05,160 --> 00:16:09,040 encodes all sorts of information about the source of the waves. 488 00:16:09,040 --> 00:16:11,080 By comparing the observed waveform 489 00:16:11,080 --> 00:16:14,840 to theoretical models generated by supercomputers, 490 00:16:14,840 --> 00:16:17,800 we can determine the masses of the objects involved 491 00:16:17,800 --> 00:16:21,040 in the collision, their distance from Earth, their spins, 492 00:16:21,040 --> 00:16:22,840 and even the orientation of their orbits. 493 00:16:22,840 --> 00:16:24,880 It's like a cosmic Rosetta Stone, 494 00:16:24,880 --> 00:16:27,880 allowing us to decode the secrets hidden 495 00:16:27,880 --> 00:16:29,880 within these ripples of spacetime. 496 00:16:29,880 --> 00:16:31,240 That's a great analogy. 497 00:16:31,240 --> 00:16:34,040 And with each detection, we're refining our ability 498 00:16:34,040 --> 00:16:37,120 to read these cosmic messages, unlocking 499 00:16:37,120 --> 00:16:39,320 deeper and deeper layers of understanding 500 00:16:39,320 --> 00:16:40,360 about the universe. 501 00:16:40,360 --> 00:16:41,880 This is all so fascinating. 502 00:16:41,880 --> 00:16:46,040 But I'm curious, with all this talk about black holes 503 00:16:46,040 --> 00:16:50,400 and neutron stars, are there any gravitational waves 504 00:16:50,400 --> 00:16:55,760 that we could potentially detect from less extreme events? 505 00:16:55,760 --> 00:16:57,520 That's a great question. 506 00:16:57,520 --> 00:16:59,720 While the most powerful gravitational waves 507 00:16:59,720 --> 00:17:02,160 come from these cataclysmic events, 508 00:17:02,160 --> 00:17:04,640 there are also fainter waves generated 509 00:17:04,640 --> 00:17:06,600 by less dramatic objects. 510 00:17:06,600 --> 00:17:10,380 For example, pulsars, those rapidly spinning neutron stars 511 00:17:10,380 --> 00:17:13,760 we mentioned earlier, emit continuous gravitational waves, 512 00:17:13,760 --> 00:17:16,040 though much weaker than those from mergers. 513 00:17:16,040 --> 00:17:18,840 So it's like a constant hum compared to a sudden crash. 514 00:17:18,840 --> 00:17:20,120 Exactly. 515 00:17:20,120 --> 00:17:22,200 And as our detectors become more sensitive, 516 00:17:22,200 --> 00:17:24,240 we might be able to detect these continuous waves 517 00:17:24,240 --> 00:17:27,080 from pulsars, providing us with another tool 518 00:17:27,080 --> 00:17:29,920 to study these fascinating objects. 519 00:17:29,920 --> 00:17:32,360 It seems like the possibilities are truly endless. 520 00:17:32,360 --> 00:17:32,920 They are. 521 00:17:32,920 --> 00:17:35,360 I can't wait to see what the future holds for this field. 522 00:17:35,360 --> 00:17:38,160 But before we wrap up, I have one final question. 523 00:17:38,160 --> 00:17:40,800 With all this focus on the scientific discoveries, 524 00:17:40,800 --> 00:17:42,840 do you ever just step back and marvel 525 00:17:42,840 --> 00:17:45,360 at the sheer wonder of it all? 526 00:17:45,360 --> 00:17:49,120 The fact that we can detect these ripples in spacetime, 527 00:17:49,120 --> 00:17:52,560 these echoes from the most distant reaches of the cosmos. 528 00:17:52,560 --> 00:17:53,760 Oh, absolutely. 529 00:17:53,760 --> 00:17:55,680 It's one of the things that drew me to this field 530 00:17:55,680 --> 00:17:57,160 in the first place. 531 00:17:57,160 --> 00:17:59,560 The idea that we can listen to the universe, 532 00:17:59,560 --> 00:18:01,800 that we can peer into the heart of black holes 533 00:18:01,800 --> 00:18:05,400 and witness the birth of heavy elements. 534 00:18:05,400 --> 00:18:07,760 It's both humbling and exhilarating. 535 00:18:07,760 --> 00:18:08,560 It really is. 536 00:18:08,560 --> 00:18:09,080 Yeah. 537 00:18:09,080 --> 00:18:11,560 It's a reminder that we are part of something much bigger 538 00:18:11,560 --> 00:18:13,840 than ourselves, a cosmic symphony that's been playing out 539 00:18:13,840 --> 00:18:15,400 for billions of years. 540 00:18:15,400 --> 00:18:17,720 And we're just beginning to understand the music. 541 00:18:17,720 --> 00:18:19,840 Yeah, it really is awe-inspiring to think 542 00:18:19,840 --> 00:18:22,200 about all the secrets the universe is still holding, 543 00:18:22,200 --> 00:18:23,640 just waiting to be discovered. 544 00:18:23,640 --> 00:18:24,240 Absolutely. 545 00:18:24,240 --> 00:18:26,520 And it sounds like gravitational wave astronomy 546 00:18:26,520 --> 00:18:29,640 is going to play a major role in unlocking those secrets. 547 00:18:29,640 --> 00:18:33,600 Without a doubt, it's a field that's bursting with potential. 548 00:18:33,600 --> 00:18:37,000 And we're only just beginning to explore the possibilities. 549 00:18:37,000 --> 00:18:38,920 Before we wrap up, I wanted to touch on something 550 00:18:38,920 --> 00:18:39,920 you mentioned earlier. 551 00:18:39,920 --> 00:18:40,560 Sure. 552 00:18:40,560 --> 00:18:42,720 The idea of using gravitational waves 553 00:18:42,720 --> 00:18:45,920 to test Einstein's theory of general relativity. 554 00:18:45,920 --> 00:18:46,480 Right. 555 00:18:46,480 --> 00:18:47,640 Can you elaborate on that a bit? 556 00:18:47,640 --> 00:18:48,140 Sure. 557 00:18:48,140 --> 00:18:50,040 Einstein's theory of general relativity 558 00:18:50,040 --> 00:18:53,920 has been incredibly successful in explaining 559 00:18:53,920 --> 00:18:57,960 the behavior of gravity on large scales, 560 00:18:57,960 --> 00:19:00,640 from the orbits of planets to the bending of light 561 00:19:00,640 --> 00:19:02,200 around massive objects. 562 00:19:02,200 --> 00:19:02,960 Right. 563 00:19:02,960 --> 00:19:06,480 But it's never been tested in the most extreme environments. 564 00:19:06,480 --> 00:19:07,040 OK. 565 00:19:07,040 --> 00:19:10,400 Like those found near black holes and neutron stars. 566 00:19:10,400 --> 00:19:12,160 So gravitational waves offer a way 567 00:19:12,160 --> 00:19:15,760 to test Einstein's theory in these extreme conditions, 568 00:19:15,760 --> 00:19:17,280 where gravity is pushed to its limits. 569 00:19:17,280 --> 00:19:18,320 Exactly. 570 00:19:18,320 --> 00:19:20,640 By studying the gravitational waves emitted 571 00:19:20,640 --> 00:19:22,800 from these events, we can see if they 572 00:19:22,800 --> 00:19:25,280 behave as predicted by general relativity, 573 00:19:25,280 --> 00:19:30,080 or if there are deviations that might point to new physics, 574 00:19:30,080 --> 00:19:34,560 new theories of gravity that we haven't even conceived of yet. 575 00:19:34,560 --> 00:19:36,080 So it's not just about confirming 576 00:19:36,080 --> 00:19:37,480 what we already know. 577 00:19:37,480 --> 00:19:39,900 It's also about potentially discovering something entirely 578 00:19:39,900 --> 00:19:42,920 new, something that could revolutionize our understanding 579 00:19:42,920 --> 00:19:43,760 of the universe. 580 00:19:43,760 --> 00:19:44,880 Precisely. 581 00:19:44,880 --> 00:19:48,560 Every time we detect a new gravitational wave signal, 582 00:19:48,560 --> 00:19:52,640 we're essentially conducting an experiment on gravity itself, 583 00:19:52,640 --> 00:19:55,720 probing its nature in ways that were never before possible. 584 00:19:55,720 --> 00:19:57,240 Wow, that's incredible. 585 00:19:57,240 --> 00:20:00,560 It's like we're using the universe as a giant laboratory 586 00:20:00,560 --> 00:20:02,440 to test our most fundamental theories. 587 00:20:02,440 --> 00:20:03,200 Exactly. 588 00:20:03,200 --> 00:20:04,680 And who knows what we'll find? 589 00:20:04,680 --> 00:20:07,780 Perhaps general relativity will hold up perfectly, 590 00:20:07,780 --> 00:20:10,120 even in these extreme environments. 591 00:20:10,120 --> 00:20:12,600 Or perhaps we'll find subtle deviations that 592 00:20:12,600 --> 00:20:14,680 hint at something new, something that 593 00:20:14,680 --> 00:20:18,200 will force us to rethink our understanding of gravity 594 00:20:18,200 --> 00:20:20,280 and the universe as a whole. 595 00:20:20,280 --> 00:20:20,960 It's possible. 596 00:20:20,960 --> 00:20:23,600 Either way, it's bound to be a groundbreaking discovery. 597 00:20:23,600 --> 00:20:24,720 Yeah, I think so. 598 00:20:24,720 --> 00:20:27,400 This has been an absolutely mind-blowing deep dive 599 00:20:27,400 --> 00:20:29,320 into the world of gravitational waves. 600 00:20:29,320 --> 00:20:30,200 It has been. 601 00:20:30,200 --> 00:20:32,400 I feel like I've only just begun to grasp 602 00:20:32,400 --> 00:20:34,760 the immensity of what we're talking about. 603 00:20:34,760 --> 00:20:36,920 But it's been a truly fascinating journey. 604 00:20:36,920 --> 00:20:39,240 It's been my pleasure to share this journey with you. 605 00:20:39,240 --> 00:20:39,720 Well, thank you. 606 00:20:39,720 --> 00:20:42,200 It's a privilege to be part of the scientific revolution. 607 00:20:42,200 --> 00:20:44,080 And I can't wait to see what the future holds 608 00:20:44,080 --> 00:20:46,120 for gravitational wave astronomy. 609 00:20:46,120 --> 00:20:46,720 Yeah. 610 00:20:46,720 --> 00:20:49,320 Who knows what secrets the universe will whisper to us 611 00:20:49,320 --> 00:20:50,120 next? 612 00:20:50,120 --> 00:20:53,040 I'm on the edge of my seat waiting to find out. 613 00:20:53,040 --> 00:20:54,940 And to our listeners, we hope you 614 00:20:54,940 --> 00:20:57,840 found this exploration of gravitational waves 615 00:20:57,840 --> 00:20:59,540 as captivating as we did. 616 00:20:59,540 --> 00:21:00,680 I hope so. 617 00:21:00,680 --> 00:21:03,640 If you'd like to delve deeper into the mysteries of the cosmos, 618 00:21:03,640 --> 00:21:06,560 be sure to follow and subscribe to Cosmos in a Pod 619 00:21:06,560 --> 00:21:09,200 and our YouTube channel for more deep dives 620 00:21:09,200 --> 00:21:10,560 into the wonders of the universe. 621 00:21:10,560 --> 00:21:11,380 Sounds good. 622 00:21:11,380 --> 00:21:15,480 Until next time, keep looking up and keep wondering.