1 00:00:00,000 --> 00:00:03,320 Welcome to Cosmos in a Pod, Space, and Astronomy series. 2 00:00:03,320 --> 00:00:07,360 Today, we're taking a deep dive into a truly awe-inspiring 3 00:00:07,360 --> 00:00:10,720 subject, and that's spiral galaxies. 4 00:00:10,720 --> 00:00:12,000 They really are something else. 5 00:00:12,000 --> 00:00:15,640 Imagine just a swirling, glittering city of stars, 6 00:00:15,640 --> 00:00:18,440 and gas, and dust spanning hundreds 7 00:00:18,440 --> 00:00:19,560 of thousands of light years. 8 00:00:19,560 --> 00:00:20,960 It's hard to wrap your head around it. 9 00:00:20,960 --> 00:00:22,320 Yeah, it's difficult to grasp. 10 00:00:22,320 --> 00:00:23,280 It really is. 11 00:00:23,280 --> 00:00:24,680 But that's a spiral galaxy. 12 00:00:24,680 --> 00:00:26,600 And one of them, the Milky Way, is our home. 13 00:00:26,600 --> 00:00:28,520 Our home, and not just any home. 14 00:00:28,520 --> 00:00:30,920 It's a dynamic and evolving one. 15 00:00:30,920 --> 00:00:34,040 These grand structures, they're shaped by fundamental forces. 16 00:00:34,040 --> 00:00:37,160 We're still trying to fully understand 17 00:00:37,160 --> 00:00:40,080 gravity, the enigmatic influence of dark matter, and even 18 00:00:40,080 --> 00:00:41,880 collisions with other galaxies. 19 00:00:41,880 --> 00:00:42,560 Collisions. 20 00:00:42,560 --> 00:00:43,060 Yeah. 21 00:00:43,060 --> 00:00:44,360 That sounds intense. 22 00:00:44,360 --> 00:00:47,520 I always pictured galaxies as these serene, almost static 23 00:00:47,520 --> 00:00:48,040 objects. 24 00:00:48,040 --> 00:00:48,540 Right. 25 00:00:48,540 --> 00:00:51,280 So how do these collisions and these mysterious forces 26 00:00:51,280 --> 00:00:53,120 shape the galaxies we observe? 27 00:00:53,120 --> 00:00:55,640 Well, first, let's define what makes a spiral galaxy 28 00:00:55,640 --> 00:00:56,900 a spiral galaxy. 29 00:00:56,900 --> 00:00:59,920 Imagine a flat disk rotating gracefully, 30 00:00:59,920 --> 00:01:01,960 like a cosmic record player. 31 00:01:01,960 --> 00:01:06,960 But instead of grooves, picture brilliant, sweeping spiral arms 32 00:01:06,960 --> 00:01:10,240 spiraling outwards from a bright central bulge. 33 00:01:10,240 --> 00:01:12,280 That's an image that never gets old. 34 00:01:12,280 --> 00:01:14,840 Those elegant, almost artistic spirals 35 00:01:14,840 --> 00:01:16,440 against the blackness of space. 36 00:01:16,440 --> 00:01:16,960 Right. 37 00:01:16,960 --> 00:01:18,800 And these arms, they aren't just for show. 38 00:01:18,800 --> 00:01:19,300 OK. 39 00:01:19,300 --> 00:01:21,160 They're hotbeds of star formation, 40 00:01:21,160 --> 00:01:23,760 where clouds of gas and dust are compressed, 41 00:01:23,760 --> 00:01:27,840 igniting new stars and dazzling displays of cosmic fireworks. 42 00:01:27,840 --> 00:01:30,280 So these arms are constantly churning out new stars. 43 00:01:30,280 --> 00:01:31,160 That's incredible. 44 00:01:31,160 --> 00:01:32,920 But if these arms are constantly moving, 45 00:01:32,920 --> 00:01:34,760 why don't they just fade away over time? 46 00:01:34,760 --> 00:01:36,080 How do they maintain their shape? 47 00:01:36,080 --> 00:01:38,560 That's where the concept of density waves comes in. 48 00:01:38,560 --> 00:01:41,160 Imagine ripples in a pond, but on a galactic scale. 49 00:01:41,160 --> 00:01:41,660 OK. 50 00:01:41,660 --> 00:01:42,960 These waves move through the galaxy, 51 00:01:42,960 --> 00:01:45,080 compressing the gas and dust as they pass this, 52 00:01:45,080 --> 00:01:46,960 triggers bursts of star formation, 53 00:01:46,960 --> 00:01:48,520 lighting up the spiral arms. 54 00:01:48,520 --> 00:01:50,400 It's almost like a cosmic traffic jam, 55 00:01:50,400 --> 00:01:52,420 causing pileups of matter and igniting 56 00:01:52,420 --> 00:01:54,000 a wave of stellar bursts. 57 00:01:54,000 --> 00:01:55,360 That's a great analogy. 58 00:01:55,360 --> 00:01:57,520 I can almost picture those waves of density 59 00:01:57,520 --> 00:02:00,720 sweeping through the galaxy, leaving a trail of newborn stars 60 00:02:00,720 --> 00:02:01,800 in their wake. 61 00:02:01,800 --> 00:02:05,160 But how do these waves even get started? 62 00:02:05,160 --> 00:02:08,440 Is there a galactic speed bump out there causing these ripples? 63 00:02:08,440 --> 00:02:11,320 That's a question that has puzzled astronomers for decades. 64 00:02:11,320 --> 00:02:11,820 OK. 65 00:02:11,820 --> 00:02:13,360 Some believe these waves are triggered 66 00:02:13,360 --> 00:02:16,080 by gravitational interactions with other galaxies, 67 00:02:16,080 --> 00:02:19,480 like a cosmic nudge that sets those ripples in motion. 68 00:02:19,480 --> 00:02:22,520 Others propose they arise from processes within the galaxy 69 00:02:22,520 --> 00:02:25,880 itself, perhaps related to the rotation of the central bar 70 00:02:25,880 --> 00:02:27,520 or the distribution of mass. 71 00:02:27,520 --> 00:02:28,840 So it's still a bit of a mystery. 72 00:02:28,840 --> 00:02:31,320 We're not entirely sure what sets those galactic waves 73 00:02:31,320 --> 00:02:33,440 in motion, but either way, it results 74 00:02:33,440 --> 00:02:36,440 in those stunning spiral arms we see in so many galaxies. 75 00:02:36,440 --> 00:02:37,240 Exactly. 76 00:02:37,240 --> 00:02:39,680 And to make things even more interesting, 77 00:02:39,680 --> 00:02:43,280 those bright, massive stars born in the spiral arms 78 00:02:43,280 --> 00:02:45,400 have relatively short lifespans. 79 00:02:45,400 --> 00:02:48,600 They burn through their fuel quickly, eventually exploding 80 00:02:48,600 --> 00:02:49,920 a supernovae. 81 00:02:49,920 --> 00:02:52,400 So it's a constant cycle of birth and death 82 00:02:52,400 --> 00:02:54,880 playing out across these vast cosmic canvases. 83 00:02:54,880 --> 00:02:55,380 Yeah. 84 00:02:55,380 --> 00:02:56,160 It's pretty remarkable. 85 00:02:56,160 --> 00:02:58,160 But you mentioned something about galaxies colliding. 86 00:02:58,160 --> 00:02:59,720 How does that fit into the picture? 87 00:02:59,720 --> 00:03:03,160 When galaxies collide, things get really interesting. 88 00:03:03,160 --> 00:03:04,840 The gravitational forces involved 89 00:03:04,840 --> 00:03:08,040 can distort their shapes, trigger intense bursts 90 00:03:08,040 --> 00:03:10,340 of star formation, and even merge them 91 00:03:10,340 --> 00:03:11,800 into something entirely new. 92 00:03:11,800 --> 00:03:13,960 So instead of a serene cosmic ballet, 93 00:03:13,960 --> 00:03:18,080 it's more like a chaotic mosh pit of stars and gas. 94 00:03:18,080 --> 00:03:19,040 In a way, yes. 95 00:03:19,040 --> 00:03:22,480 It's a dramatic process that can completely reshape a galaxy. 96 00:03:22,480 --> 00:03:24,480 Spiral galaxies can be transformed 97 00:03:24,480 --> 00:03:27,320 into elliptical galaxies, which are more rounded and lack 98 00:03:27,320 --> 00:03:29,080 those distinct spiral arms. 99 00:03:29,080 --> 00:03:31,400 It's almost like a cosmic remodeling project, 100 00:03:31,400 --> 00:03:33,440 taking these elegant structures and morphing them 101 00:03:33,440 --> 00:03:34,720 into something else entirely. 102 00:03:34,720 --> 00:03:37,320 And speaking of collisions, our Milky Way 103 00:03:37,320 --> 00:03:39,800 is on a collision course with our neighbor, the Andromeda 104 00:03:39,800 --> 00:03:40,400 galaxy. 105 00:03:40,400 --> 00:03:40,900 Hold on. 106 00:03:40,900 --> 00:03:42,360 You're saying our galaxy is going 107 00:03:42,360 --> 00:03:43,920 to collide with another galaxy? 108 00:03:43,920 --> 00:03:44,440 Yeah. 109 00:03:44,440 --> 00:03:45,560 When is that happening? 110 00:03:45,560 --> 00:03:45,880 Yeah. 111 00:03:45,880 --> 00:03:48,160 And what's going to happen to us in our solar system? 112 00:03:48,160 --> 00:03:49,000 Mark your calendars. 113 00:03:49,000 --> 00:03:51,600 It's in about 4.5 billion years. 114 00:03:51,600 --> 00:03:52,880 But don't worry too much. 115 00:03:52,880 --> 00:03:55,200 The vast distances between stars mean 116 00:03:55,200 --> 00:03:56,920 it's unlikely our solar system will 117 00:03:56,920 --> 00:03:58,920 experience a direct collision. 118 00:03:58,920 --> 00:04:00,720 However, the gravitational interactions 119 00:04:00,720 --> 00:04:02,960 will dramatically reshape both galaxies, 120 00:04:02,960 --> 00:04:05,240 triggering intense star formation 121 00:04:05,240 --> 00:04:08,360 and possibly flinging stars out into intergalactic space. 122 00:04:08,360 --> 00:04:11,080 4.5 billion years is a long way off. 123 00:04:11,080 --> 00:04:11,680 It is. 124 00:04:11,680 --> 00:04:13,360 But that's still a pretty wild thought. 125 00:04:13,360 --> 00:04:13,860 Yeah. 126 00:04:13,860 --> 00:04:17,560 So our galaxy, which we see as this constant familial presence 127 00:04:17,560 --> 00:04:20,600 in the night sky, is actually in constant motion, 128 00:04:20,600 --> 00:04:23,960 evolving over billions of years and eventually colliding 129 00:04:23,960 --> 00:04:25,520 with another galaxy. 130 00:04:25,520 --> 00:04:27,280 It puts things into perspective, doesn't it? 131 00:04:27,280 --> 00:04:28,160 Absolutely. 132 00:04:28,160 --> 00:04:30,560 And it's just a taste of the complex processes that 133 00:04:30,560 --> 00:04:32,640 shape these magnificent structures. 134 00:04:32,640 --> 00:04:34,320 But to understand them fully, we need 135 00:04:34,320 --> 00:04:36,380 to delve into one of the biggest mysteries 136 00:04:36,380 --> 00:04:38,360 in modern astronomy, dark matter. 137 00:04:38,360 --> 00:04:39,480 Dark matter. 138 00:04:39,480 --> 00:04:40,880 That sounds pretty intimidating. 139 00:04:40,880 --> 00:04:42,800 I know it's something we can't even see. 140 00:04:42,800 --> 00:04:46,280 But it somehow plays a crucial role in how galaxies behave. 141 00:04:46,280 --> 00:04:46,800 It does. 142 00:04:46,800 --> 00:04:49,160 You see, astronomers noticed something strange about the 143 00:04:49,160 --> 00:04:50,920 rotation of spiral galaxies. 144 00:04:50,920 --> 00:04:53,280 The stars in the outer regions were moving way faster 145 00:04:53,280 --> 00:04:55,720 than they should based on the visible matter alone. 146 00:04:55,720 --> 00:04:57,760 It's like something invisible was giving them 147 00:04:57,760 --> 00:04:59,240 an extra gravitational kick. 148 00:04:59,240 --> 00:05:01,960 So it's like a phantom hand guiding those stars. 149 00:05:01,960 --> 00:05:02,860 Exactly. 150 00:05:02,860 --> 00:05:06,280 Astronomers theorize that a massive halo of dark matter 151 00:05:06,280 --> 00:05:10,000 surrounds each spiral galaxy, providing the extra gravity 152 00:05:10,000 --> 00:05:12,880 needed to explain those super fast stars. 153 00:05:12,880 --> 00:05:15,080 It acts like an invisible scaffolding holding 154 00:05:15,080 --> 00:05:16,800 the entire structure together. 155 00:05:16,800 --> 00:05:17,760 That's incredible. 156 00:05:17,760 --> 00:05:19,640 So this invisible stuff is actually 157 00:05:19,640 --> 00:05:20,840 holding galaxies together. 158 00:05:20,840 --> 00:05:23,880 It's like the glue that keeps a whole cosmic structure 159 00:05:23,880 --> 00:05:24,800 from flying apart. 160 00:05:24,800 --> 00:05:26,120 Yeah, it's pretty amazing. 161 00:05:26,120 --> 00:05:28,760 But if it's invisible, how do we even know it's there? 162 00:05:28,760 --> 00:05:30,880 How do we discover this dark matter? 163 00:05:30,880 --> 00:05:33,360 It's a fascinating story and one that 164 00:05:33,360 --> 00:05:36,180 has revolutionized our understanding of the universe. 165 00:05:36,180 --> 00:05:38,040 It all started with those observations 166 00:05:38,040 --> 00:05:39,520 of galaxy rotation. 167 00:05:39,520 --> 00:05:43,080 But to fully grasp how we know dark matter is real, 168 00:05:43,080 --> 00:05:44,640 we need to delve into the evidence. 169 00:05:44,640 --> 00:05:46,440 And that's where things get really exciting. 170 00:05:46,440 --> 00:05:47,960 It all boils down to gravity. 171 00:05:47,960 --> 00:05:50,500 You see, we know how much visible matter, stars, gas, 172 00:05:50,500 --> 00:05:52,680 and dust exists in a galaxy. 173 00:05:52,680 --> 00:05:54,560 And from that, we can calculate how much gravity 174 00:05:54,560 --> 00:05:55,600 should be present. 175 00:05:55,600 --> 00:05:57,680 But when you look at how fast those outer stars are 176 00:05:57,680 --> 00:05:59,520 whipping around the galaxy, it's like they're 177 00:05:59,520 --> 00:06:02,480 being influenced by a much stronger gravitational force 178 00:06:02,480 --> 00:06:04,440 than the visible matter can account for. 179 00:06:04,440 --> 00:06:07,880 So it's like watching a car take a corner way too fast. 180 00:06:07,880 --> 00:06:09,760 Something must be holding it on the road. 181 00:06:09,760 --> 00:06:12,560 Some invisible force preventing it from spinning out. 182 00:06:12,560 --> 00:06:14,600 And in the case of galaxies, that invisible force 183 00:06:14,600 --> 00:06:15,920 is dark matter. 184 00:06:15,920 --> 00:06:16,680 Precisely. 185 00:06:16,680 --> 00:06:19,040 And it's not just galaxy rotation. 186 00:06:19,040 --> 00:06:22,200 We see evidence of dark matter's gravitational influence 187 00:06:22,200 --> 00:06:25,160 on a much larger scale, affecting how galaxies cluster 188 00:06:25,160 --> 00:06:27,640 together and even bending the path of light 189 00:06:27,640 --> 00:06:29,200 as it travels through the universe. 190 00:06:29,200 --> 00:06:32,320 It's like an invisible web holding the entire cosmic 191 00:06:32,320 --> 00:06:33,720 structure together. 192 00:06:33,720 --> 00:06:36,440 It's mind boggling to think that something we can't see 193 00:06:36,440 --> 00:06:39,360 makes up such a huge portion of the universe. 194 00:06:39,360 --> 00:06:41,960 But if dark matter is so crucial, 195 00:06:41,960 --> 00:06:45,600 how did these spiral galaxies form in the early universe, 196 00:06:45,600 --> 00:06:48,080 when the universe was denser and dark matter would have 197 00:06:48,080 --> 00:06:49,880 been more evenly distributed? 198 00:06:49,880 --> 00:06:51,440 That's a great question, and one that 199 00:06:51,440 --> 00:06:53,760 pushes at the boundaries of our current understanding, 200 00:06:53,760 --> 00:06:56,000 it seems, that even in the early universe, when things were 201 00:06:56,000 --> 00:06:58,880 more chaotic, dark matter still played a key role 202 00:06:58,880 --> 00:07:01,000 in seeding the formation of galaxies. 203 00:07:01,000 --> 00:07:04,280 So even in that cosmic soup of the early universe, 204 00:07:04,280 --> 00:07:07,040 dark matter was acting like a shepherd gathering matter 205 00:07:07,040 --> 00:07:10,520 together to form those first galaxies. 206 00:07:10,520 --> 00:07:11,880 It's a good way to think about it. 207 00:07:11,880 --> 00:07:14,480 And were those early galaxies all spirals, 208 00:07:14,480 --> 00:07:16,800 or were there other types of galaxies back then? 209 00:07:16,800 --> 00:07:19,320 Well, those early galaxies were smaller and less structured 210 00:07:19,320 --> 00:07:21,640 than the majestic spirals we see today. 211 00:07:21,640 --> 00:07:24,200 Recent observations suggest that spiral galaxies 212 00:07:24,200 --> 00:07:26,160 might have been more common in the early universe 213 00:07:26,160 --> 00:07:27,320 than we previously thought. 214 00:07:27,320 --> 00:07:27,600 Really? 215 00:07:27,600 --> 00:07:29,200 I thought the early universe was thought 216 00:07:29,200 --> 00:07:31,480 to be more chaotic, with galaxies colliding 217 00:07:31,480 --> 00:07:34,520 more frequently, resulting in those less defined elliptical 218 00:07:34,520 --> 00:07:35,400 galaxies? 219 00:07:35,400 --> 00:07:38,240 That's what astronomers believe for a long time, however. 220 00:07:38,240 --> 00:07:41,040 With powerful new telescopes like the James Webb Space 221 00:07:41,040 --> 00:07:43,440 Telescope, we're getting clearer glimpses 222 00:07:43,440 --> 00:07:44,960 into the early universe. 223 00:07:44,960 --> 00:07:47,880 And those observations are challenging our assumptions. 224 00:07:47,880 --> 00:07:50,560 We're seeing more evidence of early spiral galaxies, 225 00:07:50,560 --> 00:07:52,760 suggesting that the conditions for forming 226 00:07:52,760 --> 00:07:55,720 these organized structures might have existed much earlier 227 00:07:55,720 --> 00:07:56,560 than we thought. 228 00:07:56,560 --> 00:07:59,520 So spiral galaxies aren't just a recent phenomenon. 229 00:07:59,520 --> 00:08:01,360 They've been part of the cosmic landscape 230 00:08:01,360 --> 00:08:04,200 for a very long time, influencing the evolution 231 00:08:04,200 --> 00:08:05,480 of the universe itself. 232 00:08:05,480 --> 00:08:06,120 Absolutely. 233 00:08:06,120 --> 00:08:09,000 But as we've discussed, they're not static structures. 234 00:08:09,000 --> 00:08:10,000 They evolve. 235 00:08:10,000 --> 00:08:10,720 They interact. 236 00:08:10,720 --> 00:08:11,880 They collide. 237 00:08:11,880 --> 00:08:13,760 And speaking of collisions, we can't 238 00:08:13,760 --> 00:08:16,840 forget that our own Milky Way is on a collision course 239 00:08:16,840 --> 00:08:18,360 with the Andromeda Galaxy. 240 00:08:18,360 --> 00:08:20,800 Right, that's a pretty big event in our galaxy's future. 241 00:08:20,800 --> 00:08:23,720 But is it just a one-off, or are these collisions 242 00:08:23,720 --> 00:08:25,760 common occurrences in the life of a galaxy? 243 00:08:25,760 --> 00:08:28,800 Galactic interactions and mergers are surprisingly common. 244 00:08:28,800 --> 00:08:31,440 In fact, many of the spiral galaxies we see today 245 00:08:31,440 --> 00:08:34,720 likely formed through mergers with smaller galaxies. 246 00:08:34,720 --> 00:08:37,240 These mergers can trigger bursts of star formation, 247 00:08:37,240 --> 00:08:39,560 reshape the galaxy's structure, and even strip away 248 00:08:39,560 --> 00:08:43,200 gas and dust, leaving a more quiescent galaxy behind. 249 00:08:43,200 --> 00:08:45,760 So it's like a cosmic dance with galaxies constantly 250 00:08:45,760 --> 00:08:47,280 interacting, merging, and changing 251 00:08:47,280 --> 00:08:48,360 over billions of years. 252 00:08:48,360 --> 00:08:49,360 Yeah, it really is. 253 00:08:49,360 --> 00:08:51,160 But what happens to a spiral galaxy 254 00:08:51,160 --> 00:08:52,640 after all the action dies down? 255 00:08:52,640 --> 00:08:55,440 What happens when it runs out of gas to form new stars? 256 00:08:55,440 --> 00:08:56,640 That's a great question. 257 00:08:56,640 --> 00:08:59,960 As the gas supply dwindles, star formation slows down, 258 00:08:59,960 --> 00:09:02,520 and the galaxy enters a quieter phase. 259 00:09:02,520 --> 00:09:04,800 The brilliant blue hues of young stars 260 00:09:04,800 --> 00:09:08,600 fade, giving way to the reddish glow of older stars. 261 00:09:08,600 --> 00:09:10,640 The spiral arms become less prominent, 262 00:09:10,640 --> 00:09:12,560 and the galaxy gradually transitions 263 00:09:12,560 --> 00:09:14,000 into a more settled state. 264 00:09:14,000 --> 00:09:17,320 So like a cosmic retirement party, the galaxy winds down, 265 00:09:17,320 --> 00:09:20,000 the lights dim, and things get a bit, well, less exciting. 266 00:09:20,000 --> 00:09:23,600 But could something jolt it back to life, even 267 00:09:23,600 --> 00:09:24,720 in this quieter state? 268 00:09:24,720 --> 00:09:25,280 That's right. 269 00:09:25,280 --> 00:09:27,440 And while this might seem like the end of the story, 270 00:09:27,440 --> 00:09:29,000 the universe is full of surprises. 271 00:09:29,000 --> 00:09:31,080 Even in their twilight years, galaxies 272 00:09:31,080 --> 00:09:33,640 can experience unexpected events, interactions 273 00:09:33,640 --> 00:09:36,680 with smaller galaxies, or even the influence of dark matter 274 00:09:36,680 --> 00:09:40,120 can stir things up, triggering new bursts of star formation 275 00:09:40,120 --> 00:09:41,960 or altering the galaxy's structure. 276 00:09:41,960 --> 00:09:44,560 So even in their golden years, galaxies 277 00:09:44,560 --> 00:09:47,440 can still have a few tricks up their sleeves. 278 00:09:47,440 --> 00:09:50,280 It's incredible to think that these grand structures are 279 00:09:50,280 --> 00:09:52,920 in constant flux, shaped by forces. 280 00:09:52,920 --> 00:09:55,000 We're still trying to fully comprehend, 281 00:09:55,000 --> 00:09:56,560 and we've only just begun to scratch 282 00:09:56,560 --> 00:09:58,320 the surface of understanding them. 283 00:09:58,320 --> 00:10:00,280 Yeah, it really makes you appreciate 284 00:10:00,280 --> 00:10:03,560 the sheer scale and complexity of the universe, doesn't it? 285 00:10:03,560 --> 00:10:06,640 We've talked about density waves, galactic collisions, 286 00:10:06,640 --> 00:10:08,120 and the invisible hand of dark matter. 287 00:10:08,120 --> 00:10:09,280 Oh, yeah. 288 00:10:09,280 --> 00:10:12,320 But I'm guessing there are still plenty of mysteries swirling 289 00:10:12,320 --> 00:10:14,360 around these spiral galaxies. 290 00:10:14,360 --> 00:10:14,860 Absolutely. 291 00:10:14,860 --> 00:10:16,600 For example, we've touched upon the idea 292 00:10:16,600 --> 00:10:18,840 that spiral arms might be triggered by interactions 293 00:10:18,840 --> 00:10:21,620 with other galaxies, but there's also the possibility 294 00:10:21,620 --> 00:10:23,780 that they arise naturally from processes 295 00:10:23,780 --> 00:10:25,680 within the galaxy itself. 296 00:10:25,680 --> 00:10:27,840 So it's a bit of a chicken or the egg scenario. 297 00:10:27,840 --> 00:10:29,480 We're not sure if those spiral arms 298 00:10:29,480 --> 00:10:32,360 are caused by external nudges or internal dynamics. 299 00:10:32,360 --> 00:10:32,860 Exactly. 300 00:10:32,860 --> 00:10:35,520 And then there's the question of how those spiral structures are 301 00:10:35,520 --> 00:10:37,360 maintained over billions of years. 302 00:10:37,360 --> 00:10:39,260 Those density waves are constantly moving, 303 00:10:39,260 --> 00:10:42,160 so why don't the arms just dissipate over time? 304 00:10:42,160 --> 00:10:43,440 It does seem counterintuitive. 305 00:10:43,440 --> 00:10:46,120 If it's all just a wave, you'd think those arms would eventually 306 00:10:46,120 --> 00:10:47,040 just fade away. 307 00:10:47,040 --> 00:10:49,280 Right, but something keeps those waves going, 308 00:10:49,280 --> 00:10:51,040 something keeps those arms defined, 309 00:10:51,040 --> 00:10:54,040 and that's where the interplay of gravity gas dynamics 310 00:10:54,040 --> 00:10:56,280 and star formation gets really intriguing. 311 00:10:56,280 --> 00:10:59,220 It's a complex dance that we're still trying to fully decipher. 312 00:10:59,220 --> 00:11:01,300 It sounds like there's still so much we don't know 313 00:11:01,300 --> 00:11:02,880 about these majestic structures. 314 00:11:02,880 --> 00:11:05,880 Where do we even begin to tackle these questions? 315 00:11:05,880 --> 00:11:07,600 What are the next steps for astronomers 316 00:11:07,600 --> 00:11:09,080 studying spiral galaxies? 317 00:11:09,080 --> 00:11:12,080 Well, as we mentioned earlier, the James Webb Space Telescope 318 00:11:12,080 --> 00:11:14,680 is already giving us unprecedented views 319 00:11:14,680 --> 00:11:15,720 of the early universe. 320 00:11:15,720 --> 00:11:19,100 Being able to see those early galaxies, those baby spirals, 321 00:11:19,100 --> 00:11:23,400 and the process of formation is providing invaluable insights. 322 00:11:23,400 --> 00:11:25,160 It's like having a time machine, allowing 323 00:11:25,160 --> 00:11:28,800 us to see how these spiral structures first emerged. 324 00:11:28,800 --> 00:11:31,240 Are there any other tools or missions on the horizon 325 00:11:31,240 --> 00:11:32,320 that have you excited? 326 00:11:32,320 --> 00:11:33,120 Absolutely. 327 00:11:33,120 --> 00:11:35,040 The Nancy Grace Roman Space Telescope 328 00:11:35,040 --> 00:11:36,960 is set to launch in a few years, and it 329 00:11:36,960 --> 00:11:39,000 will have a wide field of view, allowing 330 00:11:39,000 --> 00:11:41,760 us to survey vast areas of the sky 331 00:11:41,760 --> 00:11:44,560 and study the distribution and evolution of galaxies 332 00:11:44,560 --> 00:11:46,120 in unprecedented detail. 333 00:11:46,120 --> 00:11:48,880 So it's like having a panoramic view of the cosmos, 334 00:11:48,880 --> 00:11:51,640 letting us see the bigger picture of how galaxies are 335 00:11:51,640 --> 00:11:54,520 born, how they change, and how they interact with each other 336 00:11:54,520 --> 00:11:55,680 over billions of years. 337 00:11:55,680 --> 00:11:56,400 Precisely. 338 00:11:56,400 --> 00:11:58,640 And then we have the Square Kilometer Array, 339 00:11:58,640 --> 00:12:02,000 a radio telescope that will be the largest and most sensitive 340 00:12:02,000 --> 00:12:06,080 ever built. It will be able to detect incredibly faint signals 341 00:12:06,080 --> 00:12:08,800 from the early universe, essentially giving us 342 00:12:08,800 --> 00:12:12,060 a glimpse into the cosmic dawn when the first stars 343 00:12:12,060 --> 00:12:14,040 and galaxies ignited. 344 00:12:14,040 --> 00:12:16,640 Feels like we're on the verge of a golden age of astronomy 345 00:12:16,640 --> 00:12:19,000 with all these incredible tools at our disposal. 346 00:12:19,000 --> 00:12:20,720 What are some of the big picture questions 347 00:12:20,720 --> 00:12:22,960 you hope these new discoveries will help us answer? 348 00:12:22,960 --> 00:12:25,680 Some of the most fundamental questions about our universe. 349 00:12:25,680 --> 00:12:26,960 How did it all begin? 350 00:12:26,960 --> 00:12:28,520 What were those first galaxies like? 351 00:12:28,520 --> 00:12:31,680 How did the universe evolve from that early chaotic state 352 00:12:31,680 --> 00:12:34,160 to the structured cosmos we observe today? 353 00:12:34,160 --> 00:12:36,560 And perhaps most importantly, what is the ultimate fate 354 00:12:36,560 --> 00:12:37,920 of our own cosmic home? 355 00:12:37,920 --> 00:12:40,720 Big questions indeed, but questions 356 00:12:40,720 --> 00:12:43,520 that spiral galaxies, these intricate and enigmatic 357 00:12:43,520 --> 00:12:46,600 structures, might hold the key to answering. 358 00:12:46,600 --> 00:12:49,760 It's been a fascinating journey exploring these cosmic wonders 359 00:12:49,760 --> 00:12:53,760 from their elegant spiral arms to the mysteries of dark matter 360 00:12:53,760 --> 00:12:55,640 and the drama of galactic collisions. 361 00:12:55,640 --> 00:12:56,360 It has. 362 00:12:56,360 --> 00:12:59,280 And it's a reminder that we are part of something truly 363 00:12:59,280 --> 00:13:02,000 awe-inspiring, a vast and intricate universe that's 364 00:13:02,000 --> 00:13:04,120 still unfolding before our very eyes. 365 00:13:04,120 --> 00:13:06,280 So the next time we look up at the night sky 366 00:13:06,280 --> 00:13:08,640 and see those faint smudges of light, 367 00:13:08,640 --> 00:13:10,760 those distant spiral galaxies, we'll 368 00:13:10,760 --> 00:13:13,080 know that they're not just pretty pictures. 369 00:13:13,080 --> 00:13:15,040 They're cosmic time capsules. 370 00:13:15,040 --> 00:13:18,640 Each one, a story of star birth, galactic evolution, 371 00:13:18,640 --> 00:13:20,400 and the enduring mysteries of the universe. 372 00:13:20,400 --> 00:13:20,880 Exactly. 373 00:13:20,880 --> 00:13:22,800 They're a testament to the beauty complexity 374 00:13:22,800 --> 00:13:24,640 and enduring wonder of the cosmos. 375 00:13:24,640 --> 00:13:26,320 Well, I think that wraps up our deep dive 376 00:13:26,320 --> 00:13:28,880 into the fascinating world of spiral galaxies. 377 00:13:28,880 --> 00:13:31,040 If you want to continue exploring this topic, 378 00:13:31,040 --> 00:13:33,240 there are some incredible resources available online 379 00:13:33,240 --> 00:13:34,120 and in libraries. 380 00:13:34,120 --> 00:13:36,320 And of course, we encourage you to follow and subscribe 381 00:13:36,320 --> 00:13:38,800 to Cosmos in a Pods podcast and YouTube channel 382 00:13:38,800 --> 00:13:41,880 for more fascinating insights into space and science. 383 00:13:41,880 --> 00:13:42,380 That's right. 384 00:13:42,380 --> 00:13:44,920 We're constantly exploring new topics, interviewing experts, 385 00:13:44,920 --> 00:13:47,240 and bringing you the latest discoveries from the world 386 00:13:47,240 --> 00:13:48,640 astronomy and beyond. 387 00:13:48,640 --> 00:13:51,360 So until next time, keep looking up, stay curious, 388 00:13:51,360 --> 00:14:15,960 and never stop exploring the wonders of the universe.