1 00:00:00,000 --> 00:00:02,500 Welcome back to Cosmos in a Pod. 2 00:00:02,500 --> 00:00:04,200 Get ready to have your mind blown, 3 00:00:04,200 --> 00:00:07,400 because today we're diving deep into the world of pulsars. 4 00:00:07,400 --> 00:00:10,960 Yeah, these incredible objects, they're basically, 5 00:00:10,960 --> 00:00:13,560 they pack the mass of the sun into something 6 00:00:13,560 --> 00:00:15,320 like the size of a city. 7 00:00:15,320 --> 00:00:17,200 The sun squeezed into a city, that's 8 00:00:17,200 --> 00:00:18,800 like almost impossible to imagine. 9 00:00:18,800 --> 00:00:20,880 Yeah, they're really some of the most extreme 10 00:00:20,880 --> 00:00:22,920 and intriguing objects in the universe. 11 00:00:22,920 --> 00:00:25,560 OK, so tell me what exactly are pulsars. 12 00:00:25,560 --> 00:00:28,040 Well, pulsars are a type of neutron star, 13 00:00:28,040 --> 00:00:31,320 which is what's left after a massive star explodes 14 00:00:31,320 --> 00:00:32,360 in a supernova. 15 00:00:32,360 --> 00:00:32,920 OK. 16 00:00:32,920 --> 00:00:35,960 So imagine a star much bigger than our sun running out 17 00:00:35,960 --> 00:00:36,840 of fuel. 18 00:00:36,840 --> 00:00:40,480 Its core collapses in on itself under the force of gravity, 19 00:00:40,480 --> 00:00:42,120 crushing everything together. 20 00:00:42,120 --> 00:00:43,680 So it's like a cosmic implosion. 21 00:00:43,680 --> 00:00:45,280 Yeah, you could say that. 22 00:00:45,280 --> 00:00:48,240 But how does that turn a star into this super dense object 23 00:00:48,240 --> 00:00:49,040 you're describing? 24 00:00:49,040 --> 00:00:52,360 Right, so during this collapse, the protons and electrons 25 00:00:52,360 --> 00:00:56,440 in the star's core are forced together, forming neutrons, 26 00:00:56,440 --> 00:00:58,800 hence the name neutron star. 27 00:00:58,800 --> 00:00:59,640 Makes sense. 28 00:00:59,640 --> 00:01:01,880 And this creates an object so dense that it's 29 00:01:01,880 --> 00:01:03,760 almost beyond comprehension. 30 00:01:03,760 --> 00:01:06,560 A teaspoon full of neutron star material 31 00:01:06,560 --> 00:01:08,240 would weigh billions of tons. 32 00:01:08,240 --> 00:01:10,800 Billions of tons, that's insane. 33 00:01:10,800 --> 00:01:14,040 OK, so we've got this incredibly dense leftover core of a star. 34 00:01:14,040 --> 00:01:15,840 Is that what makes it a pulsar? 35 00:01:15,840 --> 00:01:16,840 Not quite. 36 00:01:16,840 --> 00:01:20,400 What makes a pulsar special is that it spins incredibly fast 37 00:01:20,400 --> 00:01:24,280 and emits beams of energy from its magnetic poles. 38 00:01:24,280 --> 00:01:27,280 So as the star's core collapses, it also 39 00:01:27,280 --> 00:01:28,760 starts spinning rapidly. 40 00:01:28,760 --> 00:01:29,560 OK. 41 00:01:29,560 --> 00:01:31,720 Think of a figure skater pulling in their arms. 42 00:01:31,720 --> 00:01:32,400 I see. 43 00:01:32,400 --> 00:01:35,840 They spin faster as their mass becomes more concentrated. 44 00:01:35,840 --> 00:01:39,120 Same principle applies here, but on a much grander scale. 45 00:01:39,120 --> 00:01:41,400 So it's like the star is winding up as it collapses. 46 00:01:41,400 --> 00:01:41,840 Right. 47 00:01:41,840 --> 00:01:43,920 And you mentioned something about beams of energy. 48 00:01:43,920 --> 00:01:45,120 Where do those come from? 49 00:01:45,120 --> 00:01:46,800 Well, neutron stars have incredibly 50 00:01:46,800 --> 00:01:50,240 strong magnetic fields, trillions of times stronger 51 00:01:50,240 --> 00:01:51,840 than Earth's magnetic field. 52 00:01:51,840 --> 00:01:52,340 Wow. 53 00:01:52,340 --> 00:01:55,240 These magnetic fields channel charge particles, 54 00:01:55,240 --> 00:01:58,280 causing them to emit radiation from the star's magnetic poles. 55 00:01:58,280 --> 00:02:00,920 We can almost picture it like a giant cosmic lighthouse. 56 00:02:00,920 --> 00:02:01,560 Yeah, exactly. 57 00:02:01,560 --> 00:02:04,280 OK, so we have this super dense spinning star 58 00:02:04,280 --> 00:02:07,200 with beams of radiation shooting out from its poles. 59 00:02:07,200 --> 00:02:08,760 But why do we call them pulsars? 60 00:02:08,760 --> 00:02:10,600 What's so pulsy about them? 61 00:02:10,600 --> 00:02:11,040 Right. 62 00:02:11,040 --> 00:02:13,920 The name pulsar comes from the way we observe them. 63 00:02:13,920 --> 00:02:14,440 Oh. 64 00:02:14,440 --> 00:02:16,760 The magnetic axis of a pulsar is usually 65 00:02:16,760 --> 00:02:19,960 tilted at an angle compared to its rotational axis. 66 00:02:19,960 --> 00:02:20,480 I see. 67 00:02:20,480 --> 00:02:23,840 So as the pulsar spins, these beams of radiation 68 00:02:23,840 --> 00:02:25,880 sweep across space. 69 00:02:25,880 --> 00:02:26,360 OK. 70 00:02:26,360 --> 00:02:29,560 And if Earth happens to be in the path of one of those beams, 71 00:02:29,560 --> 00:02:31,960 we see it as a pulse of radiation. 72 00:02:31,960 --> 00:02:32,720 That makes sense. 73 00:02:32,720 --> 00:02:34,880 So it's not like the beams themselves are pulsing. 74 00:02:34,880 --> 00:02:37,040 It's just that we only see them when they happen 75 00:02:37,040 --> 00:02:38,000 to sweep past Earth. 76 00:02:38,000 --> 00:02:38,320 Right. 77 00:02:38,320 --> 00:02:39,560 It really is like a lighthouse. 78 00:02:39,560 --> 00:02:42,120 But are all pulsars the same? 79 00:02:42,120 --> 00:02:44,080 I imagine they could have different spin rates 80 00:02:44,080 --> 00:02:45,720 and strengths of magnetic fields. 81 00:02:45,720 --> 00:02:46,720 You're absolutely right. 82 00:02:46,720 --> 00:02:47,220 OK. 83 00:02:47,220 --> 00:02:48,860 Pulsars come in a variety of types. 84 00:02:48,860 --> 00:02:50,960 The most common are radio pulsars. 85 00:02:50,960 --> 00:02:51,600 Right. 86 00:02:51,600 --> 00:02:54,260 These emit beams of radio waves, which 87 00:02:54,260 --> 00:02:56,840 we can detect here on Earth using radio telescopes. 88 00:02:56,840 --> 00:02:58,760 So it was radio waves that first gave away 89 00:02:58,760 --> 00:03:00,080 the existence of these pulsars. 90 00:03:00,080 --> 00:03:00,360 That's right. 91 00:03:00,360 --> 00:03:01,160 That's pretty cool. 92 00:03:01,160 --> 00:03:02,000 Yeah. 93 00:03:02,000 --> 00:03:04,840 I'm curious, though, what other kinds of pulsars are there? 94 00:03:04,840 --> 00:03:07,440 Do they all emit radio waves? 95 00:03:07,440 --> 00:03:08,200 Not at all. 96 00:03:08,200 --> 00:03:08,700 OK. 97 00:03:08,700 --> 00:03:11,600 Some pulsars emit X-rays instead of radio waves. 98 00:03:11,600 --> 00:03:14,040 These are called, you guessed it, X-ray pulsars. 99 00:03:14,040 --> 00:03:14,540 Right. 100 00:03:14,540 --> 00:03:16,400 They're typically found in binary systems, 101 00:03:16,400 --> 00:03:18,920 which means they're orbiting around another star. 102 00:03:18,920 --> 00:03:20,200 We had a binary system. 103 00:03:20,200 --> 00:03:23,760 So it's like two stars locked in a cosmic dance orbiting 104 00:03:23,760 --> 00:03:24,280 each other. 105 00:03:24,280 --> 00:03:24,840 Exactly. 106 00:03:24,840 --> 00:03:25,340 Right. 107 00:03:25,340 --> 00:03:27,000 And in the case of X-ray pulsars, 108 00:03:27,000 --> 00:03:30,240 they're pulling material away from their companion star. 109 00:03:30,240 --> 00:03:30,740 Right. 110 00:03:30,740 --> 00:03:33,040 As this material falls onto the pulsar, 111 00:03:33,040 --> 00:03:36,560 it heats up, producing intense X-ray emissions. 112 00:03:36,560 --> 00:03:38,440 So it's like a cosmic X-ray machine 113 00:03:38,440 --> 00:03:40,520 cowered by a stellar diet. 114 00:03:40,520 --> 00:03:43,520 So we've got radio pulsars, X-ray pulsars. 115 00:03:43,520 --> 00:03:44,440 Are there any others? 116 00:03:44,440 --> 00:03:46,840 Well, there's another type that's even more extreme. 117 00:03:46,840 --> 00:03:47,560 Magnetars. 118 00:03:47,560 --> 00:03:48,320 Magnetars. 119 00:03:48,320 --> 00:03:49,600 What makes them so extreme? 120 00:03:49,600 --> 00:03:52,160 Magnetars are a rare type of pulsar 121 00:03:52,160 --> 00:03:56,240 with incredibly strong magnetic fields, billions of times 122 00:03:56,240 --> 00:03:58,080 stronger than those of regular pulsars. 123 00:03:58,080 --> 00:03:58,720 Billions. 124 00:03:58,720 --> 00:03:59,840 Wow. 125 00:03:59,840 --> 00:04:01,480 I can't even fathom that. 126 00:04:01,480 --> 00:04:03,960 What makes their magnetic field so powerful? 127 00:04:03,960 --> 00:04:05,320 That's a bit of a mystery. 128 00:04:05,320 --> 00:04:08,520 We still don't fully understand how magnetars get 129 00:04:08,520 --> 00:04:11,280 such intense magnetic fields. 130 00:04:11,280 --> 00:04:14,200 But what we do know is that these magnetic fields produce 131 00:04:14,200 --> 00:04:17,480 powerful bursts of X-rays and gamma rays. 132 00:04:17,480 --> 00:04:19,880 So they're the real powerhouses of the pulsar family. 133 00:04:19,880 --> 00:04:20,800 You could say that. 134 00:04:20,800 --> 00:04:21,360 OK. 135 00:04:21,360 --> 00:04:23,160 And a great example of a magnetar 136 00:04:23,160 --> 00:04:25,440 is the one located in the Crab Nebula. 137 00:04:25,440 --> 00:04:27,840 It's incredibly bright, and astronomers have been studying 138 00:04:27,840 --> 00:04:29,040 it for centuries. 139 00:04:29,040 --> 00:04:30,120 Wait, the Crab Nebula? 140 00:04:30,120 --> 00:04:32,400 Isn't that the rendant of a supernova that exploded 141 00:04:32,400 --> 00:04:33,640 almost 1,000 years ago? 142 00:04:33,640 --> 00:04:34,560 It is indeed. 143 00:04:34,560 --> 00:04:35,240 Wow. 144 00:04:35,240 --> 00:04:37,400 That supernova was so bright that it was visible 145 00:04:37,400 --> 00:04:39,040 during the daytime for weeks. 146 00:04:39,040 --> 00:04:39,760 Really? 147 00:04:39,760 --> 00:04:42,480 And at its center is this incredible magnetar 148 00:04:42,480 --> 00:04:45,480 still spinning and radiating energy 149 00:04:45,480 --> 00:04:46,880 all these centuries later. 150 00:04:46,880 --> 00:04:47,880 That's incredible. 151 00:04:47,880 --> 00:04:49,840 So we've got these cosmic lighthouses, 152 00:04:49,840 --> 00:04:54,240 some emitting radio waves, others blasting out X-rays, 153 00:04:54,240 --> 00:04:56,640 and then we have the superpowered magnetars. 154 00:04:56,640 --> 00:04:59,200 It's mind-blowing to think about these things spinning out 155 00:04:59,200 --> 00:05:00,640 there in space. 156 00:05:00,640 --> 00:05:03,360 But how do scientists even find these pulsars 157 00:05:03,360 --> 00:05:05,200 in the vastness of the cosmos? 158 00:05:05,200 --> 00:05:07,560 Well, it all started with a bit of a surprise, actually. 159 00:05:07,560 --> 00:05:12,240 Back in 1967, a young astronomer named Jocelyn Bell Brunel 160 00:05:12,240 --> 00:05:15,280 was analyzing radio signals from space 161 00:05:15,280 --> 00:05:17,520 when she noticed something peculiar. 162 00:05:17,520 --> 00:05:18,520 What did she find? 163 00:05:18,520 --> 00:05:19,600 Was it aliens? 164 00:05:19,600 --> 00:05:20,920 Not quite. 165 00:05:20,920 --> 00:05:25,720 She detected these incredibly regular pulses of radio waves 166 00:05:25,720 --> 00:05:29,640 so precise that they seemed almost artificial. 167 00:05:29,640 --> 00:05:33,120 At first, they even jokingly called the source LGM-1, 168 00:05:33,120 --> 00:05:35,240 which stood for little green men. 169 00:05:35,240 --> 00:05:37,040 I can see why they might have thought that. 170 00:05:37,040 --> 00:05:38,920 But it turned out to be something even more fascinating. 171 00:05:38,920 --> 00:05:40,040 Exactly. 172 00:05:40,040 --> 00:05:42,560 Further analysis revealed that the signals were coming 173 00:05:42,560 --> 00:05:46,840 from a rapidly rotating neutron star, the first pulsar ever 174 00:05:46,840 --> 00:05:48,040 discovered. 175 00:05:48,040 --> 00:05:51,080 And since then, we've found thousands more, each 176 00:05:51,080 --> 00:05:53,240 with its unique characteristics. 177 00:05:53,240 --> 00:05:55,520 So it was the rhythmic pulses that gave them away. 178 00:05:55,520 --> 00:05:56,080 That's right. 179 00:05:56,080 --> 00:05:57,240 That makes sense. 180 00:05:57,240 --> 00:05:58,920 But here's what I'm really curious about. 181 00:05:58,920 --> 00:06:00,520 Why are pulsars so important? 182 00:06:00,520 --> 00:06:03,560 Why should we care about these crazy spinning stars? 183 00:06:03,560 --> 00:06:05,200 That's a great question. 184 00:06:05,200 --> 00:06:07,600 Pulsars are more than just fascinating objects. 185 00:06:07,600 --> 00:06:10,320 They're incredibly valuable tools for astronomers 186 00:06:10,320 --> 00:06:11,520 and physicists. 187 00:06:11,520 --> 00:06:14,000 For one, they act as natural laboratories 188 00:06:14,000 --> 00:06:16,000 for studying extreme physics. 189 00:06:16,000 --> 00:06:16,840 Extreme physics? 190 00:06:16,840 --> 00:06:17,680 What do you mean by that? 191 00:06:17,680 --> 00:06:20,200 Well, remember how we talked about the incredible density 192 00:06:20,200 --> 00:06:21,200 of neutron stars? 193 00:06:21,200 --> 00:06:21,680 Yeah. 194 00:06:21,680 --> 00:06:24,000 Those conditions are unlike anything 195 00:06:24,000 --> 00:06:25,520 we can create here on Earth. 196 00:06:25,520 --> 00:06:26,000 Right. 197 00:06:26,000 --> 00:06:27,920 They allow us to study how matter behaves 198 00:06:27,920 --> 00:06:30,800 under extreme pressures and densities 199 00:06:30,800 --> 00:06:32,760 and to test our theories about gravity 200 00:06:32,760 --> 00:06:34,280 and fundamental forces. 201 00:06:34,280 --> 00:06:36,720 So pulsars are helping us push the boundaries 202 00:06:36,720 --> 00:06:38,520 of our understanding of the universe. 203 00:06:38,520 --> 00:06:39,480 They are indeed. 204 00:06:39,480 --> 00:06:41,080 And that's just the beginning. 205 00:06:41,080 --> 00:06:42,840 There's so much more to explore. 206 00:06:42,840 --> 00:06:45,680 Well, I can't wait to hear more. 207 00:06:45,680 --> 00:06:47,600 Welcome back to Cosmos in a Pod. 208 00:06:47,600 --> 00:06:50,160 We're continuing our deep dive into the fascinating world 209 00:06:50,160 --> 00:06:51,360 of pulsars. 210 00:06:51,360 --> 00:06:52,920 And I'm still reeling from the fact 211 00:06:52,920 --> 00:06:56,920 that something can be as dense as a teaspoonful of neutron star 212 00:06:56,920 --> 00:06:59,640 material weighing billions of tons. 213 00:06:59,640 --> 00:07:01,120 It is truly mind boggling. 214 00:07:01,120 --> 00:07:02,720 And as we were saying before, pulsars 215 00:07:02,720 --> 00:07:04,800 are not only incredibly dense, but they also 216 00:07:04,800 --> 00:07:08,000 serve as natural laboratories for studying extreme physics. 217 00:07:08,000 --> 00:07:11,000 You mentioned that we can study gravity and fundamental forces 218 00:07:11,000 --> 00:07:12,400 through pulsars. 219 00:07:12,400 --> 00:07:13,880 Can you explain that a little more? 220 00:07:13,880 --> 00:07:16,800 What makes them so useful for that kind of research? 221 00:07:16,800 --> 00:07:19,520 Of course you see the conditions inside a neutron star 222 00:07:19,520 --> 00:07:22,280 are so extreme with gravity crushing matter 223 00:07:22,280 --> 00:07:24,640 to unimaginable densities that they 224 00:07:24,640 --> 00:07:27,800 test the limits of our current understanding of physics. 225 00:07:27,800 --> 00:07:31,160 By observing how matter behaves in these environments, 226 00:07:31,160 --> 00:07:34,440 we can gather insights into the fundamental laws of nature. 227 00:07:34,440 --> 00:07:36,560 OK, so it's like pulsars are giving us 228 00:07:36,560 --> 00:07:39,560 a glimpse into physics at its most extreme, which we could 229 00:07:39,560 --> 00:07:41,160 never replicate here on Earth. 230 00:07:41,160 --> 00:07:41,960 Precisely. 231 00:07:41,960 --> 00:07:43,760 It's like having a front row seat 232 00:07:43,760 --> 00:07:45,200 to a cosmic experiment that's been 233 00:07:45,200 --> 00:07:47,280 running for billions of years. 234 00:07:47,280 --> 00:07:48,080 That's incredible. 235 00:07:48,080 --> 00:07:50,880 Now, before we talked about the idea of using pulsars 236 00:07:50,880 --> 00:07:52,920 for navigation, can you tell me more about that? 237 00:07:52,920 --> 00:07:54,240 How would that even work? 238 00:07:54,240 --> 00:07:57,200 It's a fascinating concept called pulsar navigation. 239 00:07:57,200 --> 00:07:58,960 Imagine you're a spacecraft traveling 240 00:07:58,960 --> 00:08:01,200 vast distances through space. 241 00:08:01,200 --> 00:08:02,660 How do you know where you are? 242 00:08:02,660 --> 00:08:05,360 I guess our current GPS system wouldn't be much help out there. 243 00:08:05,360 --> 00:08:06,400 Exactly. 244 00:08:06,400 --> 00:08:08,480 But pulsars can provide a solution. 245 00:08:08,480 --> 00:08:09,000 OK. 246 00:08:09,000 --> 00:08:11,240 They emit those incredibly regular pulses, 247 00:08:11,240 --> 00:08:14,640 and we know their positions in the sky with great accuracy. 248 00:08:14,640 --> 00:08:17,520 By measuring the arrival times of those pulses 249 00:08:17,520 --> 00:08:20,200 from different pulsars, a spacecraft 250 00:08:20,200 --> 00:08:22,840 could triangulate its position in space, 251 00:08:22,840 --> 00:08:25,600 much like using GPS satellites here on Earth. 252 00:08:25,600 --> 00:08:27,240 So instead of relying on satellites, 253 00:08:27,240 --> 00:08:30,720 we could use these spinning stars as cosmic beacons 254 00:08:30,720 --> 00:08:32,720 to guide us across the galaxy. 255 00:08:32,720 --> 00:08:33,880 That's amazing. 256 00:08:33,880 --> 00:08:36,280 It's still a relatively new field of research, 257 00:08:36,280 --> 00:08:39,000 but it holds immense potential for the future of space 258 00:08:39,000 --> 00:08:41,000 exploration, especially for missions 259 00:08:41,000 --> 00:08:42,880 venturing beyond our solar system, 260 00:08:42,880 --> 00:08:46,480 where traditional navigation methods become less reliable. 261 00:08:46,480 --> 00:08:49,020 It's mind-boggling to think that we might one day 262 00:08:49,020 --> 00:08:52,760 be using pulsars to chart our course through the stars. 263 00:08:52,760 --> 00:08:54,520 Now, I have to admit, I'm still struggling 264 00:08:54,520 --> 00:08:56,920 to wrap my head around those millisecond pulsars, the ones 265 00:08:56,920 --> 00:08:59,540 that spin hundreds of times per second. 266 00:08:59,540 --> 00:09:01,680 How do they get to be so fast? 267 00:09:01,680 --> 00:09:02,480 Yes. 268 00:09:02,480 --> 00:09:04,560 The speed demons of the pulsar world, 269 00:09:04,560 --> 00:09:06,560 their incredible spin rates, are thought 270 00:09:06,560 --> 00:09:08,840 to be the result of a process called accretion. 271 00:09:08,840 --> 00:09:09,400 Accretion. 272 00:09:09,400 --> 00:09:10,520 I'm not familiar with that term. 273 00:09:10,520 --> 00:09:11,600 Can you break it down for me? 274 00:09:11,600 --> 00:09:13,400 Certainly, accretion happens when a pulsar 275 00:09:13,400 --> 00:09:15,640 is in a binary system with a companion star, 276 00:09:15,640 --> 00:09:17,800 just like we discussed with X-ray pulsars. 277 00:09:17,800 --> 00:09:20,600 The pulsar's strong gravity pulls material 278 00:09:20,600 --> 00:09:24,120 from its companion, and as this material spirals inward, 279 00:09:24,120 --> 00:09:27,160 it transfers angular momentum to the pulsar, causing 280 00:09:27,160 --> 00:09:29,000 it to spin faster and faster. 281 00:09:29,000 --> 00:09:30,920 So it was like a spinning top being whipped up 282 00:09:30,920 --> 00:09:32,400 by the inflowing matter. 283 00:09:32,400 --> 00:09:35,480 A very apt analogy, and over millions of years, 284 00:09:35,480 --> 00:09:39,200 this process can spin a pulsar up to those incredible speeds, 285 00:09:39,200 --> 00:09:41,120 sometimes even reaching thousands 286 00:09:41,120 --> 00:09:42,400 of rotations per second. 287 00:09:42,400 --> 00:09:43,640 That's just phenomenal. 288 00:09:43,640 --> 00:09:46,060 I remember you mentioned that these millisecond pulsars are 289 00:09:46,060 --> 00:09:48,160 also incredibly precise timekeepers. 290 00:09:48,160 --> 00:09:48,680 That's right. 291 00:09:48,680 --> 00:09:50,480 Their rotational periods are so stable 292 00:09:50,480 --> 00:09:53,200 that they rival atomic clocks here on Earth. 293 00:09:53,200 --> 00:09:56,120 We're talking about variations of just a few microseconds 294 00:09:56,120 --> 00:09:57,000 over many years. 295 00:09:57,000 --> 00:10:00,360 Wow, so what can we do with such precise cosmic clocks? 296 00:10:00,360 --> 00:10:02,920 Their precision makes them invaluable tools 297 00:10:02,920 --> 00:10:05,440 for a wide range of scientific research, for instance. 298 00:10:05,440 --> 00:10:08,280 We can use them to test fundamental physical theories, 299 00:10:08,280 --> 00:10:10,320 like Einstein's theory of general relativity. 300 00:10:10,320 --> 00:10:12,640 General relativity, the theory about gravity 301 00:10:12,640 --> 00:10:14,440 and the curvature of spacetime. 302 00:10:14,440 --> 00:10:15,840 How do pulsars help us with that? 303 00:10:15,840 --> 00:10:18,040 Well, according to general relativity, 304 00:10:18,040 --> 00:10:20,160 massive objects like pulsars should 305 00:10:20,160 --> 00:10:21,880 warp spacetime around them. 306 00:10:21,880 --> 00:10:25,160 And this warping should affect the way light travels near them 307 00:10:25,160 --> 00:10:28,400 by carefully measuring the timing of pulsar signals 308 00:10:28,400 --> 00:10:30,360 as they pass through the gravitational field 309 00:10:30,360 --> 00:10:32,080 of a companion star. 310 00:10:32,080 --> 00:10:34,120 We can detect these subtle effects 311 00:10:34,120 --> 00:10:37,360 and confirm the predictions of general relativity. 312 00:10:37,360 --> 00:10:39,160 So pulsars are not only helping us 313 00:10:39,160 --> 00:10:41,760 understand the extreme conditions inside neutron 314 00:10:41,760 --> 00:10:43,840 stars, but they're also allowing us 315 00:10:43,840 --> 00:10:46,340 to test some of the most fundamental theories 316 00:10:46,340 --> 00:10:47,120 in physics. 317 00:10:47,120 --> 00:10:48,120 That's just amazing. 318 00:10:48,120 --> 00:10:48,720 Indeed. 319 00:10:48,720 --> 00:10:50,980 And there's more millisecond pulsars can also be used 320 00:10:50,980 --> 00:10:52,800 to detect gravitational waves. 321 00:10:52,800 --> 00:10:54,400 Wait, gravitational waves? 322 00:10:54,400 --> 00:10:57,440 Those ripples in spacetime caused by cataclysmic events, 323 00:10:57,440 --> 00:10:59,400 like black hole collisions. 324 00:10:59,400 --> 00:11:01,880 How can we use pulsars to detect something like that? 325 00:11:01,880 --> 00:11:04,840 It's a fascinating technique called pulsar timing arrays. 326 00:11:04,840 --> 00:11:07,560 By monitoring a network of millisecond pulsars 327 00:11:07,560 --> 00:11:09,880 spread across the sky, astronomers 328 00:11:09,880 --> 00:11:11,920 can look for tiny variations in the arrival 329 00:11:11,920 --> 00:11:13,040 times of their pulses. 330 00:11:13,040 --> 00:11:15,580 And those variations are caused by gravitational waves passing 331 00:11:15,580 --> 00:11:17,800 between us and the pulsars, like the ripples 332 00:11:17,800 --> 00:11:19,040 distorting the signal. 333 00:11:19,040 --> 00:11:19,760 Exactly. 334 00:11:19,760 --> 00:11:21,720 Imagine a gravitational wave passing 335 00:11:21,720 --> 00:11:24,760 through the space between us and a distant pulsar. 336 00:11:24,760 --> 00:11:27,880 As the wave stretches and squeezes spacetime, 337 00:11:27,880 --> 00:11:31,000 it slightly alters the distance the pulse has to travel, 338 00:11:31,000 --> 00:11:35,280 causing it to arrive a tiny bit earlier or later than expected. 339 00:11:35,280 --> 00:11:38,400 So by carefully measuring those tiny timing differences 340 00:11:38,400 --> 00:11:41,240 across multiple pulsars, we can actually 341 00:11:41,240 --> 00:11:44,160 detect these gravitational waves from billions 342 00:11:44,160 --> 00:11:45,080 of light years away. 343 00:11:45,080 --> 00:11:45,600 Precisely. 344 00:11:45,600 --> 00:11:48,120 It's like having a giant cosmic detector with pulsars 345 00:11:48,120 --> 00:11:50,960 spread across the galaxy acting as our sensors. 346 00:11:50,960 --> 00:11:52,160 This is also mind blowing. 347 00:11:52,160 --> 00:11:54,480 I knew pulsars were fascinating, but I had no idea 348 00:11:54,480 --> 00:11:56,480 they played such a crucial role in so many areas 349 00:11:56,480 --> 00:11:58,160 of astronomy and physics. 350 00:11:58,160 --> 00:11:59,960 And we've only just scratched the surface, 351 00:11:59,960 --> 00:12:02,640 despite decades of research, pulsars still 352 00:12:02,640 --> 00:12:04,200 hold many mysteries. 353 00:12:04,200 --> 00:12:05,480 Oh. 354 00:12:05,480 --> 00:12:07,000 Like what? 355 00:12:07,000 --> 00:12:08,160 You've piqued my curiosity. 356 00:12:08,160 --> 00:12:09,880 What are some of the unanswered questions 357 00:12:09,880 --> 00:12:11,540 that scientists are still grappling with? 358 00:12:11,540 --> 00:12:14,600 Well, for one, we're still not entirely sure what determines 359 00:12:14,600 --> 00:12:16,160 the lifespan of a pulsar. 360 00:12:16,160 --> 00:12:18,460 We know that they slow down over time as they lose energy, 361 00:12:18,460 --> 00:12:20,800 but the exact mechanisms and timescales involved 362 00:12:20,800 --> 00:12:22,160 are still being debated. 363 00:12:22,160 --> 00:12:24,880 So eventually, even these rapidly spinning pulsars 364 00:12:24,880 --> 00:12:26,240 will eventually fade away. 365 00:12:26,240 --> 00:12:29,400 In a sense, yes, but we're not sure how long this process 366 00:12:29,400 --> 00:12:33,160 takes or what the final fate of a pulsar might be. 367 00:12:33,160 --> 00:12:34,200 Fascinating. 368 00:12:34,200 --> 00:12:37,080 Are there any other mysteries surrounding pulsars 369 00:12:37,080 --> 00:12:39,440 that you find particularly intriguing? 370 00:12:39,440 --> 00:12:42,960 Another big question is, what happens when pulsars merge? 371 00:12:42,960 --> 00:12:45,040 We know that binary pulsars can eventually 372 00:12:45,040 --> 00:12:47,840 spiral in towards each other and collide, 373 00:12:47,840 --> 00:12:51,040 but the details of those mergers are still largely unknown. 374 00:12:51,040 --> 00:12:52,640 What do you think might happen? 375 00:12:52,640 --> 00:12:55,280 Do they create something even more exotic? 376 00:12:55,280 --> 00:12:57,960 We believe that these mergers could produce even more 377 00:12:57,960 --> 00:13:01,280 extreme objects, potentially giving birth to black holes 378 00:13:01,280 --> 00:13:03,560 or other phenomena we haven't even imagined yet. 379 00:13:03,560 --> 00:13:04,320 That's incredible. 380 00:13:04,320 --> 00:13:05,640 So there's still so much we don't 381 00:13:05,640 --> 00:13:07,120 know about these cosmic wonders. 382 00:13:07,120 --> 00:13:07,800 Absolutely. 383 00:13:07,800 --> 00:13:10,800 And that's what makes pulsar research so exciting. 384 00:13:10,800 --> 00:13:14,360 Every new discovery opens up new avenues of exploration 385 00:13:14,360 --> 00:13:16,760 and deepens our understanding of the universe. 386 00:13:16,760 --> 00:13:18,720 This has been an incredible journey so far. 387 00:13:18,720 --> 00:13:20,040 I'm eager to hear what else you have 388 00:13:20,040 --> 00:13:21,640 to share about these amazing objects. 389 00:13:21,640 --> 00:13:23,360 Shall we continue our exploration? 390 00:13:23,360 --> 00:13:26,680 Let's dive into the final part of our pulsar deep dive. 391 00:13:26,680 --> 00:13:29,080 We'll uncover even more fascinating details 392 00:13:29,080 --> 00:13:31,760 about their impact on our understanding of the cosmos. 393 00:13:31,760 --> 00:13:33,720 Welcome back to Cosmos in a Pod. 394 00:13:33,720 --> 00:13:35,640 We're on the final leg of our deep dive 395 00:13:35,640 --> 00:13:37,360 into the world of pulsars. 396 00:13:37,360 --> 00:13:39,880 And I have to say, I'm feeling a sense of awe 397 00:13:39,880 --> 00:13:43,360 at these tiny yet incredibly powerful objects. 398 00:13:43,360 --> 00:13:45,600 Yeah, they are truly remarkable, aren't they? 399 00:13:45,600 --> 00:13:47,400 And as we've been discussing, pulsars 400 00:13:47,400 --> 00:13:49,960 are not just fascinating in their own right. 401 00:13:49,960 --> 00:13:51,720 They're also incredibly valuable tools 402 00:13:51,720 --> 00:13:53,720 for astronomers and physicists. 403 00:13:53,720 --> 00:13:54,280 Exactly. 404 00:13:54,280 --> 00:13:56,800 We've talked about how they help us study extreme physics, 405 00:13:56,800 --> 00:13:59,520 test fundamental theories, and even potentially navigate 406 00:13:59,520 --> 00:14:00,640 through space. 407 00:14:00,640 --> 00:14:03,440 But you mentioned before another amazing application, 408 00:14:03,440 --> 00:14:06,160 using pulsars to detect gravitational waves. 409 00:14:06,160 --> 00:14:07,520 I'm dying to hear more about that. 410 00:14:07,520 --> 00:14:10,520 Yes, it's one of the most exciting areas of research 411 00:14:10,520 --> 00:14:11,800 in modern astronomy. 412 00:14:11,800 --> 00:14:13,600 You see those millisecond pulsars 413 00:14:13,600 --> 00:14:15,920 with their incredibly precise timing 414 00:14:15,920 --> 00:14:18,480 can act like cosmic clocks, helping us detect 415 00:14:18,480 --> 00:14:19,880 these ripples in spacetime. 416 00:14:19,880 --> 00:14:21,280 OK, I'm trying to picture this. 417 00:14:21,280 --> 00:14:23,560 How do we actually use pulsars to detect something 418 00:14:23,560 --> 00:14:25,640 as subtle as a gravitational wave? 419 00:14:25,640 --> 00:14:28,320 Imagine you have a network of these millisecond pulsars 420 00:14:28,320 --> 00:14:30,520 spread across the sky, each one pulsing 421 00:14:30,520 --> 00:14:32,520 with incredible regularity. 422 00:14:32,520 --> 00:14:34,720 Astronomers carefully monitor the arrival times 423 00:14:34,720 --> 00:14:36,200 of these pulses here on Earth. 424 00:14:36,200 --> 00:14:39,400 So it's like having a giant web of cosmic clocks 425 00:14:39,400 --> 00:14:43,200 all synchronized and ticking away with incredible accuracy. 426 00:14:43,200 --> 00:14:44,120 Precisely. 427 00:14:44,120 --> 00:14:46,480 Now imagine a gravitational wave generated 428 00:14:46,480 --> 00:14:48,680 by a cataclysmic event, like the merger 429 00:14:48,680 --> 00:14:52,480 of two supermassive black holes, passes through this network 430 00:14:52,480 --> 00:14:53,320 of pulsars. 431 00:14:53,320 --> 00:14:54,740 What happens to the pulsar signals 432 00:14:54,740 --> 00:14:56,200 when that wave passes through? 433 00:14:56,200 --> 00:14:58,840 As the wave stretches and squeezes spacetime, 434 00:14:58,840 --> 00:15:00,900 it very slightly alters the distance 435 00:15:00,900 --> 00:15:03,160 the pulses have to travel to reach us. 436 00:15:03,160 --> 00:15:05,880 This causes some pulses to arrive a tiny bit earlier 437 00:15:05,880 --> 00:15:08,200 than expected, while others arrive slightly later. 438 00:15:08,200 --> 00:15:10,560 So the gravitational wave leaves a sort of fingerprint 439 00:15:10,560 --> 00:15:12,360 on the timing of the pulsar signals. 440 00:15:12,360 --> 00:15:12,920 Exactly. 441 00:15:12,920 --> 00:15:15,800 By analyzing these tiny variations in pulsar arrival 442 00:15:15,800 --> 00:15:18,600 times across the entire network of pulsars, 443 00:15:18,600 --> 00:15:20,380 astronomers can detect the presence 444 00:15:20,380 --> 00:15:22,440 of the gravitational wave and even determine 445 00:15:22,440 --> 00:15:24,000 its direction and strength. 446 00:15:24,000 --> 00:15:25,240 Wow, that's incredible. 447 00:15:25,240 --> 00:15:27,040 It's like using these tiny spinning stars 448 00:15:27,040 --> 00:15:29,160 to listen to the symphony of the universe, 449 00:15:29,160 --> 00:15:31,560 detecting the echoes of these colossal events that 450 00:15:31,560 --> 00:15:34,240 happened billions of years ago and billions of light years 451 00:15:34,240 --> 00:15:34,880 away. 452 00:15:34,880 --> 00:15:37,980 It is a symphony of sorts, a symphony of spacetime itself. 453 00:15:37,980 --> 00:15:41,520 And it's only possible because of the incredible precision 454 00:15:41,520 --> 00:15:43,280 of those millisecond pulsars. 455 00:15:43,280 --> 00:15:44,280 It's mind blowing. 456 00:15:44,280 --> 00:15:46,400 And what kind of information can we 457 00:15:46,400 --> 00:15:48,560 learn from these gravitational waves? 458 00:15:48,560 --> 00:15:50,320 What did they tell us about the universe? 459 00:15:50,320 --> 00:15:52,620 They open a whole new window into the cosmos, 460 00:15:52,620 --> 00:15:54,600 revealing events and objects that 461 00:15:54,600 --> 00:15:57,020 are otherwise invisible to traditional telescopes, 462 00:15:57,020 --> 00:15:58,160 for instance. 463 00:15:58,160 --> 00:16:00,660 They can tell us about the mergers of supermassive black 464 00:16:00,660 --> 00:16:02,740 holes at the centers of galaxies. 465 00:16:02,740 --> 00:16:06,020 I remember you mentioned those earlier black holes millions 466 00:16:06,020 --> 00:16:09,000 or even billions of times the mass of our sun. 467 00:16:09,000 --> 00:16:11,720 Those collisions must be unimaginably powerful. 468 00:16:11,720 --> 00:16:12,640 They are indeed. 469 00:16:12,640 --> 00:16:14,480 And by studying the gravitational waves 470 00:16:14,480 --> 00:16:17,440 from these events, we can learn about the masses spins 471 00:16:17,440 --> 00:16:19,800 and even the environments of those black holes. 472 00:16:19,800 --> 00:16:22,040 So it's not just about detecting the waves. 473 00:16:22,040 --> 00:16:25,240 It's about using them to probe the most extreme 474 00:16:25,240 --> 00:16:27,160 and mysterious objects in the universe. 475 00:16:27,160 --> 00:16:27,900 Exactly. 476 00:16:27,900 --> 00:16:29,600 And it goes beyond black holes. 477 00:16:29,600 --> 00:16:31,040 Gravitational waves can also tell us 478 00:16:31,040 --> 00:16:34,240 about the early universe just moments after the Big Bang. 479 00:16:34,240 --> 00:16:35,940 They carry information about the conditions 480 00:16:35,940 --> 00:16:37,600 that existed when the universe was just 481 00:16:37,600 --> 00:16:38,720 a fraction of a second old. 482 00:16:38,720 --> 00:16:40,600 Wow, so pulsars are not only helping us 483 00:16:40,600 --> 00:16:42,960 understand the present universe, they're 484 00:16:42,960 --> 00:16:45,760 also giving us glimpses into its very beginnings. 485 00:16:45,760 --> 00:16:47,080 That's truly remarkable. 486 00:16:47,080 --> 00:16:47,640 It is. 487 00:16:47,640 --> 00:16:49,840 And it highlights just how interconnected everything 488 00:16:49,840 --> 00:16:50,840 in the cosmos is. 489 00:16:50,840 --> 00:16:55,160 These tiny spinning stars born from the deaths of massive stars 490 00:16:55,160 --> 00:16:58,160 can help us unravel the secrets of the largest structures 491 00:16:58,160 --> 00:17:00,280 and most ancient events in the universe. 492 00:17:00,280 --> 00:17:02,320 It's an incredible testament to the power 493 00:17:02,320 --> 00:17:06,400 of scientific ingenuity using these cosmic lighthouses 494 00:17:06,400 --> 00:17:09,800 to illuminate the darkest corners of the universe. 495 00:17:09,800 --> 00:17:10,480 Indeed. 496 00:17:10,480 --> 00:17:12,620 And as we continue to refine our techniques 497 00:17:12,620 --> 00:17:14,960 and build even more sensitive detectors, 498 00:17:14,960 --> 00:17:17,280 who knows what other wonders we might uncover 499 00:17:17,280 --> 00:17:19,320 using these amazing objects. 500 00:17:19,320 --> 00:17:21,120 I, for one, can't wait to find out. 501 00:17:21,120 --> 00:17:23,260 This deep dive into the world of pulsars 502 00:17:23,260 --> 00:17:24,920 has been an incredible journey filled 503 00:17:24,920 --> 00:17:27,920 with mind-boggling concepts and breathtaking discoveries. 504 00:17:27,920 --> 00:17:30,480 It has been a pleasure exploring these wonders with you. 505 00:17:30,480 --> 00:17:32,240 And for all of you listening out there, 506 00:17:32,240 --> 00:17:35,480 be sure to follow and subscribe to Cosmos in a Pod's podcast 507 00:17:35,480 --> 00:17:38,160 and YouTube channel for more fascinating insights 508 00:17:38,160 --> 00:18:05,920 into space and science.