1 00:00:00,000 --> 00:00:02,800 Welcome back to Cosmos in a Pod Space and Astronomy Series, 2 00:00:02,800 --> 00:00:04,320 episode three. 3 00:00:04,320 --> 00:00:08,840 Today, we're diving deep into one of the most, 4 00:00:08,840 --> 00:00:11,240 I don't even know, mysterious mind-bending phenomena 5 00:00:11,240 --> 00:00:14,040 in the universe, black holes. 6 00:00:14,040 --> 00:00:17,140 Yeah, they're not just these cosmic vacuum cleaners 7 00:00:17,140 --> 00:00:18,440 that kind of suck everything up, right? 8 00:00:18,440 --> 00:00:22,360 They really make us rethink how we understand space and time. 9 00:00:22,360 --> 00:00:27,360 OK, so before we get sucked in to the mysteries 10 00:00:27,360 --> 00:00:28,960 of black holes, maybe we should start 11 00:00:28,960 --> 00:00:31,320 with something a little more familiar. 12 00:00:31,320 --> 00:00:33,400 Stars, I mean, you see them every night. 13 00:00:33,400 --> 00:00:35,800 Exactly, and it turns out the life cycle of certain stars 14 00:00:35,800 --> 00:00:38,200 is really connected to the birth of black holes. 15 00:00:38,200 --> 00:00:40,280 So walk us through it. 16 00:00:40,280 --> 00:00:42,440 How does a star, this bright shining thing, 17 00:00:42,440 --> 00:00:45,160 become a black hole, this region of space time, 18 00:00:45,160 --> 00:00:46,920 where not even light can escape? 19 00:00:46,920 --> 00:00:49,360 Yeah, so it all begins with these massive stars, 20 00:00:49,360 --> 00:00:50,760 much bigger than our sun. 21 00:00:50,760 --> 00:00:52,400 And these stars live fast and die young, 22 00:00:52,400 --> 00:00:54,320 astronomically speaking, of course. 23 00:00:54,320 --> 00:00:56,080 They burn through their fuel super fast, 24 00:00:56,080 --> 00:00:58,280 and eventually, well, they run out. 25 00:00:58,280 --> 00:01:00,880 And then does the star just fizzle out? 26 00:01:00,880 --> 00:01:02,120 Well, not exactly. 27 00:01:02,120 --> 00:01:04,680 When the massive star runs out of fuel, 28 00:01:04,680 --> 00:01:06,520 gravity just takes over. 29 00:01:06,520 --> 00:01:09,440 The star's core collapses in on itself. 30 00:01:09,440 --> 00:01:12,920 And it leads to this mega explosion, a supernova. 31 00:01:12,920 --> 00:01:15,600 It's this huge cosmic fireworks show, 32 00:01:15,600 --> 00:01:17,120 this burst of light and energy that 33 00:01:17,120 --> 00:01:20,160 can be brighter than a whole galaxy for a short time. 34 00:01:20,160 --> 00:01:21,720 Wow, that's quite an exit. 35 00:01:21,720 --> 00:01:24,240 But what happens after, like the fireworks are over? 36 00:01:24,240 --> 00:01:26,120 That's where things get really interesting. 37 00:01:26,120 --> 00:01:28,880 Sometimes the core that's left over from the supernova, 38 00:01:28,880 --> 00:01:33,320 it's so massive, so dense that its own gravity just 39 00:01:33,320 --> 00:01:34,520 becomes inescapable. 40 00:01:34,520 --> 00:01:36,480 It keeps collapsing, squeezing itself down 41 00:01:36,480 --> 00:01:39,360 into this tiny, tiny point called a singularity. 42 00:01:39,360 --> 00:01:41,240 A singularity, so all that matter in the star 43 00:01:41,240 --> 00:01:44,240 gets squished down into a point with no volume? 44 00:01:44,240 --> 00:01:45,200 That's hard to picture. 45 00:01:45,200 --> 00:01:45,700 It is. 46 00:01:45,700 --> 00:01:48,280 And that's where our current understanding of physics 47 00:01:48,280 --> 00:01:49,800 kind of breaks down. 48 00:01:49,800 --> 00:01:51,520 This singularity gets covered by something 49 00:01:51,520 --> 00:01:52,760 called the event horizon. 50 00:01:52,760 --> 00:01:54,720 That's the point of no return. 51 00:01:54,720 --> 00:01:56,560 Anything that crosses it, even light, 52 00:01:56,560 --> 00:01:58,960 gets trapped by the black hole's gravity. 53 00:01:58,960 --> 00:02:03,200 So we've got this super dense point, the singularity. 54 00:02:03,200 --> 00:02:05,480 And it's surrounded by the event horizon, this boundary 55 00:02:05,480 --> 00:02:07,040 that you can't come back from. 56 00:02:07,040 --> 00:02:09,440 But how do we even know black holes exist 57 00:02:09,440 --> 00:02:12,200 if we can't see them, since they're black? 58 00:02:12,200 --> 00:02:13,440 That's a really good question. 59 00:02:13,440 --> 00:02:15,440 We can't directly see black holes, 60 00:02:15,440 --> 00:02:18,160 but we can see how they affect the stuff around them. 61 00:02:18,160 --> 00:02:19,720 Like if you were trying to find a ghost, 62 00:02:19,720 --> 00:02:21,180 you can't see the ghost itself. 63 00:02:21,180 --> 00:02:23,720 But maybe you'd see things move or lights flicker 64 00:02:23,720 --> 00:02:24,600 because of it. 65 00:02:24,600 --> 00:02:25,680 So what are the signs? 66 00:02:25,680 --> 00:02:27,800 What tells us there's a black hole hanging around? 67 00:02:27,800 --> 00:02:31,980 One way is by looking for these pairs of a black hole 68 00:02:31,980 --> 00:02:34,120 and a star orbiting each other. 69 00:02:34,120 --> 00:02:38,160 The black hole's gravity pulls matter from the star. 70 00:02:38,160 --> 00:02:41,480 It creates this swirling disk of super hot gas, 71 00:02:41,480 --> 00:02:43,280 and that's called an accretion disk. 72 00:02:43,280 --> 00:02:45,240 This is like the black hole is having a snack, 73 00:02:45,240 --> 00:02:46,620 taking a bite out of its neighbor. 74 00:02:46,620 --> 00:02:47,640 Exactly. 75 00:02:47,640 --> 00:02:50,520 And as this matter spirals into the black hole, 76 00:02:50,520 --> 00:02:54,640 it heats up, emits all this intense radiation x-rays. 77 00:02:54,640 --> 00:02:57,400 And we can detect those x-rays with our telescopes. 78 00:02:57,400 --> 00:02:59,400 That's our clue that there's a black hole there. 79 00:02:59,400 --> 00:03:02,400 It's like a cosmic fingerprint, huh? 80 00:03:02,400 --> 00:03:06,160 So let's talk about a really famous black hole, Sagittarius 81 00:03:06,160 --> 00:03:09,200 A, the one at the center of our Milky Way galaxy. 82 00:03:09,200 --> 00:03:10,320 What makes it so special? 83 00:03:10,320 --> 00:03:13,900 Well, for one, it's massive, like 4 million times 84 00:03:13,900 --> 00:03:14,880 the mass of our sun. 85 00:03:14,880 --> 00:03:18,720 It's like this giant anchor holding our galaxy together. 86 00:03:18,720 --> 00:03:20,200 4 million suns. 87 00:03:20,200 --> 00:03:20,960 Wow. 88 00:03:20,960 --> 00:03:23,080 How did we figure out it was even there, let alone 89 00:03:23,080 --> 00:03:24,480 measure how massive it is? 90 00:03:24,480 --> 00:03:27,200 By watching the stars that orbit it, 91 00:03:27,200 --> 00:03:29,480 astronomers have been tracking how stars move 92 00:03:29,480 --> 00:03:30,880 near the center of our galaxy. 93 00:03:30,880 --> 00:03:32,280 And they noticed these stars were 94 00:03:32,280 --> 00:03:35,400 zipping around some invisible object at super high speeds. 95 00:03:35,400 --> 00:03:37,440 So by looking at the way these stars move, 96 00:03:37,440 --> 00:03:40,360 we know there's this massive thing there that we can't see. 97 00:03:40,360 --> 00:03:41,160 Exactly. 98 00:03:41,160 --> 00:03:43,020 And you remember that incredible image 99 00:03:43,020 --> 00:03:45,920 of a black hole shadow from the Event Horizon telescope 100 00:03:45,920 --> 00:03:46,520 a while back? 101 00:03:46,520 --> 00:03:48,360 That was Sagittarius A. It was the first time 102 00:03:48,360 --> 00:03:50,920 we actually got to see the region around a black hole's 103 00:03:50,920 --> 00:03:52,080 event horizon. 104 00:03:52,080 --> 00:03:54,600 More proof that these incredible things exist. 105 00:03:54,600 --> 00:03:55,100 OK. 106 00:03:55,100 --> 00:03:57,440 So we've been talking supermassive black holes. 107 00:03:57,440 --> 00:03:58,800 But are there other kinds? 108 00:03:58,800 --> 00:03:59,600 Yep. 109 00:03:59,600 --> 00:04:01,520 Black holes actually come in different sizes. 110 00:04:01,520 --> 00:04:03,180 We have stellar black holes, which 111 00:04:03,180 --> 00:04:06,920 are formed when a single massive star collapses. 112 00:04:06,920 --> 00:04:09,700 They're typically just a few times the mass of our sun. 113 00:04:09,700 --> 00:04:11,440 So like the baby black holes compared 114 00:04:11,440 --> 00:04:12,800 to the supermassive ones. 115 00:04:12,800 --> 00:04:13,620 You could say that. 116 00:04:13,620 --> 00:04:16,640 And then there are these more hypothetical objects 117 00:04:16,640 --> 00:04:18,520 called primordial black holes. 118 00:04:18,520 --> 00:04:19,560 Primordial black holes. 119 00:04:19,560 --> 00:04:20,320 What are those? 120 00:04:20,320 --> 00:04:22,660 These are thought to have formed way back 121 00:04:22,660 --> 00:04:25,200 in the early universe right after the Big Bang. 122 00:04:25,200 --> 00:04:27,200 They could be tiny or they could be massive. 123 00:04:27,200 --> 00:04:29,160 But we haven't actually confirmed they exist yet. 124 00:04:29,160 --> 00:04:30,580 So they're still kind of mystery. 125 00:04:30,580 --> 00:04:34,000 But the idea that they could be out there is pretty wild. 126 00:04:34,000 --> 00:04:34,760 Definitely. 127 00:04:34,760 --> 00:04:37,360 But what really sets black holes apart, 128 00:04:37,360 --> 00:04:39,600 besides just being really dense, is that they 129 00:04:39,600 --> 00:04:41,400 can warp both time and space. 130 00:04:41,400 --> 00:04:43,600 It's like they have a whole different set of rules. 131 00:04:43,600 --> 00:04:44,120 Right. 132 00:04:44,120 --> 00:04:45,240 I've heard about that. 133 00:04:45,240 --> 00:04:47,440 Doesn't it have something to do with Einstein's theory 134 00:04:47,440 --> 00:04:48,640 of general relativity? 135 00:04:48,640 --> 00:04:49,140 Yes. 136 00:04:49,140 --> 00:04:52,160 General relativity tells us that massive objects 137 00:04:52,160 --> 00:04:54,240 like black holes actually distort 138 00:04:54,240 --> 00:04:56,080 the fabric of spacetime. 139 00:04:56,080 --> 00:04:59,480 So black holes aren't just pulling things with gravity. 140 00:04:59,480 --> 00:05:02,400 They're actually changing the way space and time 141 00:05:02,400 --> 00:05:03,200 work around them. 142 00:05:03,200 --> 00:05:04,080 That's it. 143 00:05:04,080 --> 00:05:06,560 And one of the most amazing results of this warping 144 00:05:06,560 --> 00:05:09,000 is something called time dilation. 145 00:05:09,000 --> 00:05:13,000 This means time actually slows down near a black hole 146 00:05:13,000 --> 00:05:15,680 compared to someone observing from farther away. 147 00:05:15,680 --> 00:05:16,320 Wait, hold on. 148 00:05:16,320 --> 00:05:18,880 So if I was hanging out near a black hole, 149 00:05:18,880 --> 00:05:22,320 time would move slower for me than for someone back on Earth. 150 00:05:22,320 --> 00:05:23,200 That's exactly right. 151 00:05:23,200 --> 00:05:25,360 It's like black holes have their own time zones 152 00:05:25,360 --> 00:05:26,860 where the clocks run differently. 153 00:05:26,860 --> 00:05:28,040 My mind is blown. 154 00:05:28,040 --> 00:05:30,960 So let's say, hypothetically, I take a trip to a black hole 155 00:05:30,960 --> 00:05:33,400 and then come back to Earth. 156 00:05:33,400 --> 00:05:35,320 Would I have aged less than everyone else? 157 00:05:35,320 --> 00:05:36,720 In theory, yes. 158 00:05:36,720 --> 00:05:38,720 But actually getting close enough to a black hole 159 00:05:38,720 --> 00:05:40,700 to really see this time difference 160 00:05:40,700 --> 00:05:42,000 is a whole other challenge. 161 00:05:42,000 --> 00:05:45,240 And surviving the trip is another thing altogether. 162 00:05:45,240 --> 00:05:47,660 Let's just pretend we could survive a trip to a black hole 163 00:05:47,660 --> 00:05:49,000 for a second. 164 00:05:49,000 --> 00:05:51,120 What would happen if we crossed the event horizon, 165 00:05:51,120 --> 00:05:52,880 that point of no return? 166 00:05:52,880 --> 00:05:54,000 What's on the other side? 167 00:05:54,000 --> 00:05:57,880 That's where things get really mysterious and a bit scary. 168 00:05:57,880 --> 00:06:00,640 The main idea is that if you cross the event horizon, 169 00:06:00,640 --> 00:06:03,440 you'd experience something called spaghettification. 170 00:06:03,440 --> 00:06:05,880 Spaghettification doesn't sound too good. 171 00:06:05,880 --> 00:06:07,120 What exactly is that? 172 00:06:07,120 --> 00:06:09,440 Basically, as you get closer to the black hole, 173 00:06:09,440 --> 00:06:11,940 the gravity pulling on your feet would be much stronger 174 00:06:11,940 --> 00:06:13,080 than on your head. 175 00:06:13,080 --> 00:06:15,680 So you get stretched like spaghetti 176 00:06:15,680 --> 00:06:18,360 until you're ripped apart down to the atoms. 177 00:06:18,360 --> 00:06:20,160 OK, yeah, I'll pass on that trip. 178 00:06:20,160 --> 00:06:21,440 What about the singularity? 179 00:06:21,440 --> 00:06:23,680 What happens at that incidentally dense point 180 00:06:23,680 --> 00:06:24,280 in the middle? 181 00:06:24,280 --> 00:06:27,320 That's still one of the biggest questions in physics. 182 00:06:27,320 --> 00:06:29,960 Our understanding just breaks down there. 183 00:06:29,960 --> 00:06:32,460 Some think it could be a gateway to another universe 184 00:06:32,460 --> 00:06:35,280 or maybe even like a time travel portal. 185 00:06:35,280 --> 00:06:38,360 But honestly, it's mostly uncharted territory for now. 186 00:06:38,360 --> 00:06:41,040 So maybe black holes aren't the best vacation spots. 187 00:06:41,040 --> 00:06:42,440 Probably not. 188 00:06:42,440 --> 00:06:44,520 But even though we can't physically travel to one, 189 00:06:44,520 --> 00:06:46,080 we can still study them. 190 00:06:46,080 --> 00:06:47,760 And with every new thing we learn, 191 00:06:47,760 --> 00:06:50,400 we understand more about these amazing objects 192 00:06:50,400 --> 00:06:52,440 and their role in how the universe works. 193 00:06:52,440 --> 00:06:54,920 So black holes aren't just these random weird things 194 00:06:54,920 --> 00:06:55,880 in space. 195 00:06:55,880 --> 00:06:58,240 They're actually a part of the bigger picture. 196 00:06:58,240 --> 00:06:58,840 Exactly. 197 00:06:58,840 --> 00:07:01,280 And they're not just about gravity and relativity either. 198 00:07:01,280 --> 00:07:03,360 They also connect to the world of quantum mechanics 199 00:07:03,360 --> 00:07:04,840 in some surprising ways. 200 00:07:04,840 --> 00:07:07,160 But that's a topic for another time. 201 00:07:07,160 --> 00:07:08,120 All right, sounds good. 202 00:07:08,120 --> 00:07:10,360 I'm definitely ready to learn more. 203 00:07:10,360 --> 00:07:13,320 Black holes are clearly much more than just empty space. 204 00:07:13,320 --> 00:07:16,040 They are truly mind boggling objects. 205 00:07:16,040 --> 00:07:18,840 And to our listeners, we'll be right back after a short break. 206 00:07:18,840 --> 00:07:19,920 Don't go away. 207 00:07:19,920 --> 00:07:21,920 See you soon. 208 00:07:21,920 --> 00:07:24,760 Welcome back to our deep dive into black holes. 209 00:07:24,760 --> 00:07:26,180 Before the break, we were talking 210 00:07:26,180 --> 00:07:28,480 about how they warp time and space 211 00:07:28,480 --> 00:07:31,520 and how they make us rethink gravity and relativity. 212 00:07:31,520 --> 00:07:33,760 Right, but what's really cool is that black holes also 213 00:07:33,760 --> 00:07:36,760 push the boundaries of another big theory in physics. 214 00:07:36,760 --> 00:07:37,280 Right. 215 00:07:37,280 --> 00:07:38,520 Quantum mechanics. 216 00:07:38,520 --> 00:07:39,360 Quantum mechanics. 217 00:07:39,360 --> 00:07:41,760 I thought that was about the really tiny stuff, atoms 218 00:07:41,760 --> 00:07:43,000 and particles. 219 00:07:43,000 --> 00:07:45,520 How does that connect to these giant black holes? 220 00:07:45,520 --> 00:07:47,680 It turns out black holes aren't totally black. 221 00:07:47,680 --> 00:07:50,460 They actually give off a faint kind of radiation 222 00:07:50,460 --> 00:07:52,280 called Hawking radiation. 223 00:07:52,280 --> 00:07:54,320 And this comes from quantum effects happening right 224 00:07:54,320 --> 00:07:55,400 near the event horizon. 225 00:07:55,400 --> 00:07:55,900 Hold on. 226 00:07:55,900 --> 00:07:57,440 Black holes give off radiation. 227 00:07:57,440 --> 00:07:59,980 I thought nothing, not even light, could escape them. 228 00:07:59,980 --> 00:08:02,360 That's true for things that cross the event horizon, 229 00:08:02,360 --> 00:08:04,080 that point of no return. 230 00:08:04,080 --> 00:08:06,960 But down at the quantum level, things get a little, well, 231 00:08:06,960 --> 00:08:08,080 weird. 232 00:08:08,080 --> 00:08:11,720 In quantum mechanics, empty space isn't actually empty. 233 00:08:11,720 --> 00:08:14,880 It's full of these things called virtual particles popping 234 00:08:14,880 --> 00:08:16,720 in and out of existence all the time. 235 00:08:16,720 --> 00:08:17,600 Virtual particles. 236 00:08:17,600 --> 00:08:18,600 What are those? 237 00:08:18,600 --> 00:08:21,320 Think of them like pairs of particles and antiparticles. 238 00:08:21,320 --> 00:08:23,120 They come from the vacuum of space, 239 00:08:23,120 --> 00:08:24,920 exist for a super short time. 240 00:08:24,920 --> 00:08:27,240 Then they destroy each other, and their energy 241 00:08:27,240 --> 00:08:28,400 goes back to the void. 242 00:08:28,400 --> 00:08:30,920 It's like this constant creation and destruction 243 00:08:30,920 --> 00:08:32,040 happening all the time. 244 00:08:32,040 --> 00:08:34,560 So empty space is actually buzzing with this quantum 245 00:08:34,560 --> 00:08:35,800 stuff we can't normally see. 246 00:08:35,800 --> 00:08:37,640 Yeah, that's the idea. 247 00:08:37,640 --> 00:08:40,680 Now imagine this happening near black holes event horizon. 248 00:08:40,680 --> 00:08:42,440 Sometimes one of those virtual particles 249 00:08:42,440 --> 00:08:46,120 falls into the black hole, while the other one escapes. 250 00:08:46,120 --> 00:08:49,000 And that escaping particle becomes a real particle, 251 00:08:49,000 --> 00:08:51,360 carrying away some of the black hole's energy. 252 00:08:51,360 --> 00:08:53,640 So it's like the black hole's leaking energy 253 00:08:53,640 --> 00:08:55,160 through these particles. 254 00:08:55,160 --> 00:08:57,680 But wouldn't it have to travel faster than light 255 00:08:57,680 --> 00:08:59,680 to escape the black hole's gravity? 256 00:08:59,680 --> 00:09:02,760 This is where quantum mechanics gets really interesting. 257 00:09:02,760 --> 00:09:05,000 Virtual particles don't follow the same rules 258 00:09:05,000 --> 00:09:06,600 as normal objects. 259 00:09:06,600 --> 00:09:09,760 They can do things that normal physics says are impossible, 260 00:09:09,760 --> 00:09:11,600 like being in multiple places at once 261 00:09:11,600 --> 00:09:14,000 or tunneling through barriers. 262 00:09:14,000 --> 00:09:15,920 So they're like quantum escape artists, 263 00:09:15,920 --> 00:09:17,840 finding loopholes in reality. 264 00:09:17,840 --> 00:09:18,920 That's a good way to put it. 265 00:09:18,920 --> 00:09:21,560 And over really, really long periods of time, 266 00:09:21,560 --> 00:09:25,640 this Hawking radiation makes the black hole lose mass. 267 00:09:25,640 --> 00:09:27,840 And eventually, it could even completely disappear. 268 00:09:27,840 --> 00:09:29,040 Black holes can disappear. 269 00:09:29,040 --> 00:09:31,040 I thought they were like forever. 270 00:09:31,040 --> 00:09:32,240 That's what we thought too. 271 00:09:32,240 --> 00:09:35,600 But this theory challenges that idea. 272 00:09:35,600 --> 00:09:38,480 And it brings up some big questions about information. 273 00:09:38,480 --> 00:09:39,400 Information? 274 00:09:39,400 --> 00:09:40,240 What do you mean? 275 00:09:40,240 --> 00:09:43,120 Well, quantum mechanics says information can't be destroyed. 276 00:09:43,120 --> 00:09:45,520 But if a black hole disappears, what 277 00:09:45,520 --> 00:09:47,440 happens to all the information about everything 278 00:09:47,440 --> 00:09:48,720 that fell into it? 279 00:09:48,720 --> 00:09:49,920 Did it just vanish? 280 00:09:49,920 --> 00:09:52,000 It's like when you burn a book. 281 00:09:52,000 --> 00:09:55,440 The book is gone, but the words, the stories, that information 282 00:09:55,440 --> 00:09:56,240 isn't really gone. 283 00:09:56,240 --> 00:09:58,400 It's just changed into other forms of energy. 284 00:09:58,400 --> 00:09:59,360 Exactly. 285 00:09:59,360 --> 00:10:01,740 So the question is, does something like that 286 00:10:01,740 --> 00:10:03,480 happen with black holes? 287 00:10:03,480 --> 00:10:05,560 Does the information about everything that fell in 288 00:10:05,560 --> 00:10:08,520 get encoded in the Hawking radiation somehow? 289 00:10:08,520 --> 00:10:10,480 Or is it lost forever? 290 00:10:10,480 --> 00:10:12,840 This is called the information paradox. 291 00:10:12,840 --> 00:10:14,880 And it's a huge mystery in physics. 292 00:10:14,880 --> 00:10:16,760 That's a pretty big paradox, all right. 293 00:10:16,760 --> 00:10:18,720 And it seems like it goes to the core of how 294 00:10:18,720 --> 00:10:20,640 we understand the universe. 295 00:10:20,640 --> 00:10:24,040 If information can be lost, that changes a lot 296 00:10:24,040 --> 00:10:25,180 of what we thought we knew. 297 00:10:25,180 --> 00:10:26,080 It does. 298 00:10:26,080 --> 00:10:29,320 And it shows us that we need a better theory, one that 299 00:10:29,320 --> 00:10:31,320 combines the big world of gravity 300 00:10:31,320 --> 00:10:34,720 described by general relativity with the small world 301 00:10:34,720 --> 00:10:36,040 of quantum mechanics. 302 00:10:36,040 --> 00:10:38,160 We need a theory of quantum gravity. 303 00:10:38,160 --> 00:10:40,240 Quantum gravity, yeah, we keep coming back to this. 304 00:10:40,240 --> 00:10:43,400 Every time we try to understand these big cosmic mysteries, 305 00:10:43,400 --> 00:10:45,440 we need this theory that can explain it all. 306 00:10:45,440 --> 00:10:46,240 Exactly. 307 00:10:46,240 --> 00:10:48,760 And black holes, with their crazy gravity 308 00:10:48,760 --> 00:10:50,680 and their connection to quantum stuff, 309 00:10:50,680 --> 00:10:53,920 are the perfect place to test ideas about quantum gravity. 310 00:10:53,920 --> 00:10:56,440 They're making us rethink the very basics of the universe, 311 00:10:56,440 --> 00:10:59,400 space, time, information, all of it. 312 00:10:59,400 --> 00:11:01,080 It sounds like black holes aren't just 313 00:11:01,080 --> 00:11:02,920 these objects in space. 314 00:11:02,920 --> 00:11:05,360 They're like keys to unlocking deeper truths 315 00:11:05,360 --> 00:11:06,960 about how reality works. 316 00:11:06,960 --> 00:11:08,600 That's a great way to think about it. 317 00:11:08,600 --> 00:11:10,280 They're pushing the limits of our knowledge 318 00:11:10,280 --> 00:11:13,160 and forcing us to ask really big questions. 319 00:11:13,160 --> 00:11:14,800 And who knows what answers we might find 320 00:11:14,800 --> 00:11:16,640 as we continue to explore them. 321 00:11:16,640 --> 00:11:18,720 Well, I'm ready to dive even deeper. 322 00:11:18,720 --> 00:11:20,240 Black holes have certainly shattered 323 00:11:20,240 --> 00:11:22,480 any preconceived notions I had. 324 00:11:22,480 --> 00:11:24,480 Now I want to move on to something a bit lighter. 325 00:11:24,480 --> 00:11:27,180 We've talked a lot about the darkness of black holes. 326 00:11:27,180 --> 00:11:30,680 How about we explore the possibility of light and life 327 00:11:30,680 --> 00:11:31,840 beyond our planet? 328 00:11:31,840 --> 00:11:35,240 That's a perfect transition, leaving the intense gravity 329 00:11:35,240 --> 00:11:38,520 and mind-bending physics of black holes behind 330 00:11:38,520 --> 00:11:41,360 and venturing into the search for other worlds and maybe 331 00:11:41,360 --> 00:11:42,600 even other life forms. 332 00:11:42,600 --> 00:11:46,240 The age-old question, are we alone in the universe? 333 00:11:46,240 --> 00:11:48,120 It's a question that has fascinated humanity 334 00:11:48,120 --> 00:11:49,480 for centuries. 335 00:11:49,480 --> 00:11:51,160 And now, in recent decades, we've 336 00:11:51,160 --> 00:11:54,680 made remarkable progress in our ability to search for answers. 337 00:11:54,680 --> 00:11:57,160 With powerful telescopes and ingenious techniques, 338 00:11:57,160 --> 00:11:59,860 we are discovering new planets orbiting distant stars 339 00:11:59,860 --> 00:12:01,040 at an incredible rate. 340 00:12:01,040 --> 00:12:04,200 Thousands of exoplanets, planets outside of our solar system, 341 00:12:04,200 --> 00:12:05,760 have been confirmed. 342 00:12:05,760 --> 00:12:08,680 And there are undoubtedly many more waiting to be found. 343 00:12:08,680 --> 00:12:09,960 Thousands. 344 00:12:09,960 --> 00:12:11,680 Wow, that's a lot of planets. 345 00:12:11,680 --> 00:12:13,520 What are these exoplanets like? 346 00:12:13,520 --> 00:12:15,780 Are they similar to the planets in our solar system? 347 00:12:15,780 --> 00:12:18,400 Some are, but many are quite different. 348 00:12:18,400 --> 00:12:21,040 We have found gas giants larger than Jupiter, 349 00:12:21,040 --> 00:12:23,040 rocky worlds similar in size to Earth, 350 00:12:23,040 --> 00:12:24,560 and everything in between. 351 00:12:24,560 --> 00:12:27,120 Some are scorching hot or getting close to their stars, 352 00:12:27,120 --> 00:12:29,160 while others are icy and distant, 353 00:12:29,160 --> 00:12:31,440 locked in a perpetual winter. 354 00:12:31,440 --> 00:12:33,720 It sounds like there's a whole spectrum of planetary 355 00:12:33,720 --> 00:12:34,680 possibilities out there. 356 00:12:34,680 --> 00:12:35,280 That's right. 357 00:12:35,280 --> 00:12:37,160 And as we learn more about these exoplanets, 358 00:12:37,160 --> 00:12:39,800 we're starting to ask even bolder questions. 359 00:12:39,800 --> 00:12:42,360 Could some of these worlds harbor life? 360 00:12:42,360 --> 00:12:44,360 That's the big question, isn't it? 361 00:12:44,360 --> 00:12:47,080 Are we alone in the universe, or is there life teaming out 362 00:12:47,080 --> 00:12:48,160 there on other planets? 363 00:12:48,160 --> 00:12:49,960 It's a tantalizing thought. 364 00:12:49,960 --> 00:12:52,280 Imagine oceans on distant planets, 365 00:12:52,280 --> 00:12:54,640 filled with alien creatures unlike anything 366 00:12:54,640 --> 00:12:58,040 we've ever seen, or perhaps even intelligent civilizations 367 00:12:58,040 --> 00:12:59,720 gazing up at their own night skies 368 00:12:59,720 --> 00:13:01,400 and wondering if they're alone. 369 00:13:01,400 --> 00:13:03,560 It's mind boggling to think about the possibilities. 370 00:13:03,560 --> 00:13:04,520 It is. 371 00:13:04,520 --> 00:13:06,020 And the search for life beyond Earth 372 00:13:06,020 --> 00:13:08,600 is one of the most exciting and rapidly developing 373 00:13:08,600 --> 00:13:10,160 fields in science. 374 00:13:10,160 --> 00:13:12,600 So how do scientists actually search for life 375 00:13:12,600 --> 00:13:14,480 on these distant planets? 376 00:13:14,480 --> 00:13:16,760 I mean, we can't exactly send probes out there 377 00:13:16,760 --> 00:13:18,320 to collect samples, can we? 378 00:13:18,320 --> 00:13:19,760 Not yet, at least. 379 00:13:19,760 --> 00:13:22,720 But scientists are developing incredibly sophisticated 380 00:13:22,720 --> 00:13:26,440 instruments and techniques to study exoplanets from afar. 381 00:13:26,440 --> 00:13:28,840 One approach is to analyze the light that passes 382 00:13:28,840 --> 00:13:30,520 through an exoplanet's atmosphere. 383 00:13:30,520 --> 00:13:32,520 So it's like looking at a distant street light 384 00:13:32,520 --> 00:13:33,560 through fog. 385 00:13:33,560 --> 00:13:35,560 The fog changes the way the light looks, right? 386 00:13:35,560 --> 00:13:36,640 Exactly. 387 00:13:36,640 --> 00:13:39,200 By carefully studying the light from a distant star that 388 00:13:39,200 --> 00:13:41,880 has passed through an exoplanet's atmosphere, 389 00:13:41,880 --> 00:13:44,880 scientists can detect the presence of certain gases, 390 00:13:44,880 --> 00:13:48,080 such as oxygen, methane, or water vapor. 391 00:13:48,080 --> 00:13:50,720 These gases could be signs of biological activity 392 00:13:50,720 --> 00:13:52,960 or what we call biosignatures. 393 00:13:52,960 --> 00:13:56,280 So if we detect oxygen in an exoplanet's atmosphere, 394 00:13:56,280 --> 00:13:59,280 it could be a sign that there are plants or other organisms 395 00:13:59,280 --> 00:14:02,160 producing oxygen through photosynthesis, 396 00:14:02,160 --> 00:14:03,400 just like on Earth. 397 00:14:03,400 --> 00:14:04,680 That's the idea. 398 00:14:04,680 --> 00:14:06,320 And as our technology advances, we're 399 00:14:06,320 --> 00:14:08,880 getting closer to being able to directly image 400 00:14:08,880 --> 00:14:10,280 these distant worlds. 401 00:14:10,280 --> 00:14:13,400 Imagine being able to see an exoplanet with your own eyes, 402 00:14:13,400 --> 00:14:16,360 to see its continents, its oceans, perhaps even 403 00:14:16,360 --> 00:14:17,800 signs of vegetation. 404 00:14:17,800 --> 00:14:20,880 It would be like looking through a window into another world. 405 00:14:20,880 --> 00:14:22,960 It would be an extraordinary achievement. 406 00:14:22,960 --> 00:14:24,420 And who knows, maybe one day we'll 407 00:14:24,420 --> 00:14:27,280 be able to send robotic probes to these exoplanets 408 00:14:27,280 --> 00:14:28,760 to explore them up close. 409 00:14:28,760 --> 00:14:30,560 I can't wait to see what the future hold 410 00:14:30,560 --> 00:14:32,040 for exoplanet research. 411 00:14:32,040 --> 00:14:32,640 Yeah. 412 00:14:32,640 --> 00:14:35,320 It feels like we're on the verge of some truly groundbreaking 413 00:14:35,320 --> 00:14:36,080 discoveries. 414 00:14:36,080 --> 00:14:37,200 I agree. 415 00:14:37,200 --> 00:14:41,440 The search for life beyond Earth is a grand scientific adventure. 416 00:14:41,440 --> 00:14:43,900 And it has the potential to change our understanding 417 00:14:43,900 --> 00:14:45,420 of our place in the universe. 418 00:14:45,420 --> 00:14:49,380 If we were to find evidence of even microbial life 419 00:14:49,380 --> 00:14:52,680 on another planet, it would be a monumental discovery, 420 00:14:52,680 --> 00:14:53,220 wouldn't it? 421 00:14:53,220 --> 00:14:54,120 Absolutely. 422 00:14:54,120 --> 00:14:57,080 It would demonstrate that life is not unique to Earth, 423 00:14:57,080 --> 00:14:58,760 that the spark of life can ignite 424 00:14:58,760 --> 00:15:00,360 in other corners of the cosmos. 425 00:15:00,360 --> 00:15:03,360 And what if we found evidence of intelligent life? 426 00:15:03,360 --> 00:15:05,560 That would be truly transformative, wouldn't it? 427 00:15:05,560 --> 00:15:07,040 It would be a paradigm shift. 428 00:15:07,040 --> 00:15:09,960 It would force us to reconsider our place in the universe, 429 00:15:09,960 --> 00:15:12,440 to acknowledge that we're not the only intelligent beings 430 00:15:12,440 --> 00:15:13,000 out there. 431 00:15:13,000 --> 00:15:15,920 It's both exciting and humbling to think about. 432 00:15:15,920 --> 00:15:16,720 It is. 433 00:15:16,720 --> 00:15:18,360 And it reminds us that the universe 434 00:15:18,360 --> 00:15:21,840 is full of mysteries and wonders waiting to be uncovered. 435 00:15:21,840 --> 00:15:24,000 Well, we've covered a lot of ground today. 436 00:15:24,000 --> 00:15:28,200 From the depths of black holes to the tantalizing possibilities 437 00:15:28,200 --> 00:15:30,000 of life beyond Earth. 438 00:15:30,000 --> 00:15:32,080 It's been a journey of cosmic proportions. 439 00:15:32,080 --> 00:15:33,120 It has. 440 00:15:33,120 --> 00:15:35,780 And it's a journey that's only just begun. 441 00:15:35,780 --> 00:15:38,080 As our understanding of the universe deepens, 442 00:15:38,080 --> 00:15:41,000 we're sure to encounter even more mind-boggling phenomena 443 00:15:41,000 --> 00:15:43,160 and profound questions. 444 00:15:43,160 --> 00:15:45,800 And that's what makes exploring the cosmos so captivating, 445 00:15:45,800 --> 00:15:46,680 isn't it? 446 00:15:46,680 --> 00:15:48,680 There's always something new to discover, always 447 00:15:48,680 --> 00:15:50,300 another mystery to unravel. 448 00:15:50,300 --> 00:15:51,420 Exactly. 449 00:15:51,420 --> 00:15:54,040 And it's a reminder that we should never stop asking 450 00:15:54,040 --> 00:15:56,160 questions, never stop pushing the boundaries 451 00:15:56,160 --> 00:15:56,880 of our knowledge. 452 00:15:56,880 --> 00:15:57,680 Well said. 453 00:15:57,680 --> 00:16:00,880 So until next time, keep looking up, keep wondering, 454 00:16:00,880 --> 00:16:04,200 and keep exploring the vast and mysterious universe. 455 00:16:04,200 --> 00:16:06,640 And if you've enjoyed this deep dive into the cosmos, 456 00:16:06,640 --> 00:16:09,600 be sure to follow and subscribe to Cosmos in a Pod. 457 00:16:09,600 --> 00:16:11,360 We'll be back soon with another adventure 458 00:16:11,360 --> 00:16:13,480 into the wonders of space and time. 459 00:16:13,480 --> 00:16:17,040 OK, so black holes really can just like disappear over time. 460 00:16:17,040 --> 00:16:17,960 That's wild. 461 00:16:17,960 --> 00:16:18,460 It is. 462 00:16:18,460 --> 00:16:20,800 And it raises some really big questions about, you know, 463 00:16:20,800 --> 00:16:23,480 what happens to the information that falls into a black hole? 464 00:16:23,480 --> 00:16:25,880 That's actually a big mystery in physics. 465 00:16:25,880 --> 00:16:27,680 Yeah, we touched on that a little bit before the break. 466 00:16:27,680 --> 00:16:31,200 It's like, if you throw a book into a fire, the book burns up. 467 00:16:31,200 --> 00:16:34,240 But the information in the book, the words and stories, 468 00:16:34,240 --> 00:16:35,960 they don't just disappear, do they? 469 00:16:35,960 --> 00:16:37,200 Exactly. 470 00:16:37,200 --> 00:16:39,600 So where does that information go 471 00:16:39,600 --> 00:16:40,960 when it falls into a black hole? 472 00:16:40,960 --> 00:16:42,840 Does it get destroyed? 473 00:16:42,840 --> 00:16:44,760 Or is it somehow preserved? 474 00:16:44,760 --> 00:16:46,720 That's what physicists are trying to figure out. 475 00:16:46,720 --> 00:16:48,640 It seems like black holes really push 476 00:16:48,640 --> 00:16:50,600 the limits of what we know about the universe. 477 00:16:50,600 --> 00:16:51,480 They do. 478 00:16:51,480 --> 00:16:53,880 And that's why they're so fascinating to study. 479 00:16:53,880 --> 00:16:56,400 They force us to confront some of the biggest 480 00:16:56,400 --> 00:16:58,720 questions in physics, like how do we 481 00:16:58,720 --> 00:17:01,000 combine our understanding of gravity 482 00:17:01,000 --> 00:17:03,000 with our understanding of quantum mechanics? 483 00:17:03,000 --> 00:17:05,240 That's where the idea of quantum gravity comes in, right? 484 00:17:05,240 --> 00:17:06,280 Right. 485 00:17:06,280 --> 00:17:09,200 We need a theory that can explain both the really big 486 00:17:09,200 --> 00:17:11,600 stuff, like black holes and galaxies, 487 00:17:11,600 --> 00:17:14,440 and the really small stuff, like atoms and particles. 488 00:17:14,440 --> 00:17:16,980 It's like trying to fit two giant puzzle pieces together. 489 00:17:16,980 --> 00:17:17,960 Exactly. 490 00:17:17,960 --> 00:17:20,220 And black holes might be the key to figuring out 491 00:17:20,220 --> 00:17:21,600 how those pieces fit. 492 00:17:21,600 --> 00:17:25,600 Well, I have to say, my mind is officially blown. 493 00:17:25,600 --> 00:17:27,120 I never thought I'd be so fascinated 494 00:17:27,120 --> 00:17:29,360 by these giant cosmic enigmas. 495 00:17:29,360 --> 00:17:31,520 That's the beauty of science, right? 496 00:17:31,520 --> 00:17:34,080 The more you learn, the more you realize how much there 497 00:17:34,080 --> 00:17:36,240 is still to discover. 498 00:17:36,240 --> 00:17:38,960 Speaking of discovering, you know what I'm ready for. 499 00:17:38,960 --> 00:17:40,520 A change of pace. 500 00:17:40,520 --> 00:17:43,360 We've been exploring the darkness of black holes. 501 00:17:43,360 --> 00:17:46,340 Now I'm thinking about the possibility of light and life 502 00:17:46,340 --> 00:17:48,680 beyond our own planet. 503 00:17:48,680 --> 00:17:49,600 Yes. 504 00:17:49,600 --> 00:17:52,800 The search for exoplanets and the tantalizing question 505 00:17:52,800 --> 00:17:54,920 of whether we're alone in the universe. 506 00:17:54,920 --> 00:17:55,760 Exactly. 507 00:17:55,760 --> 00:17:59,160 It's like after delving into the depths of black holes, 508 00:17:59,160 --> 00:18:01,480 I'm craving a bit of cosmic optimism. 509 00:18:01,480 --> 00:18:02,320 I understand. 510 00:18:02,320 --> 00:18:04,360 The search for life beyond Earth is certainly 511 00:18:04,360 --> 00:18:05,360 a hopeful endeavor. 512 00:18:05,360 --> 00:18:07,600 And it's one that's been gaining incredible momentum 513 00:18:07,600 --> 00:18:08,600 in recent years. 514 00:18:08,600 --> 00:18:11,120 I've heard about all these discoveries of planets orbiting 515 00:18:11,120 --> 00:18:11,800 other stars. 516 00:18:11,800 --> 00:18:12,920 What are they called again? 517 00:18:12,920 --> 00:18:13,720 Exoplanets. 518 00:18:13,720 --> 00:18:16,480 They're planets that exist outside of our own solar system. 519 00:18:16,480 --> 00:18:18,480 And thanks to advances in technology, 520 00:18:18,480 --> 00:18:20,160 we're finding them at an astonishing rate. 521 00:18:20,160 --> 00:18:20,920 Thousands, right? 522 00:18:20,920 --> 00:18:22,400 Thousands, indeed. 523 00:18:22,400 --> 00:18:24,240 And they come in all sorts of varieties. 524 00:18:24,240 --> 00:18:27,080 We found gas giants bigger than Jupiter, 525 00:18:27,080 --> 00:18:29,000 rocky planets about the size of Earth, 526 00:18:29,000 --> 00:18:30,440 and everything in between. 527 00:18:30,440 --> 00:18:33,160 So it's like a whole cosmic zoo of planets out there. 528 00:18:33,160 --> 00:18:34,720 You could say that. 529 00:18:34,720 --> 00:18:36,760 And as we learn more about these exoplanets, 530 00:18:36,760 --> 00:18:39,720 we're starting to ask even bolder questions. 531 00:18:39,720 --> 00:18:42,020 Could some of these planets be habitable? 532 00:18:42,020 --> 00:18:43,640 Could they harbor life? 533 00:18:43,640 --> 00:18:45,480 That's the ultimate question, isn't it? 534 00:18:45,480 --> 00:18:46,680 Are we alone? 535 00:18:46,680 --> 00:18:47,560 It is. 536 00:18:47,560 --> 00:18:49,200 And the search for life beyond Earth 537 00:18:49,200 --> 00:18:51,680 is one of the most exciting and rapidly developing 538 00:18:51,680 --> 00:18:53,040 fields in science. 539 00:18:53,040 --> 00:18:55,480 So how do scientists actually search for life 540 00:18:55,480 --> 00:18:57,320 on these distant planets? 541 00:18:57,320 --> 00:18:59,320 We can't exactly send a rover over there, can we? 542 00:18:59,320 --> 00:19:00,680 Not yet, anyway. 543 00:19:00,680 --> 00:19:03,960 But scientists have developed incredibly sophisticated ways 544 00:19:03,960 --> 00:19:06,280 to study exoplanets from afar. 545 00:19:06,280 --> 00:19:09,120 One technique is to analyze the light that passes 546 00:19:09,120 --> 00:19:10,760 through a planet's atmosphere. 547 00:19:10,760 --> 00:19:12,920 So it's kind of like when you look at a streetlight 548 00:19:12,920 --> 00:19:13,920 through fog, right? 549 00:19:13,920 --> 00:19:16,080 The fog changes the color of the light. 550 00:19:16,080 --> 00:19:17,280 Exactly. 551 00:19:17,280 --> 00:19:19,720 By carefully studying the light from a distant star 552 00:19:19,720 --> 00:19:22,400 that has passed through an exoplanet's atmosphere, 553 00:19:22,400 --> 00:19:24,600 scientists can figure out what gases are present. 554 00:19:24,600 --> 00:19:26,520 And if we find certain gases, like oxygen, 555 00:19:26,520 --> 00:19:27,840 that could be a sign of life, right? 556 00:19:27,840 --> 00:19:28,360 Right. 557 00:19:28,360 --> 00:19:31,400 Oxygen, methane, water vapor, these 558 00:19:31,400 --> 00:19:34,640 are all potential biosignatures, indicators 559 00:19:34,640 --> 00:19:37,440 that there might be some kind of biological activity going on. 560 00:19:37,440 --> 00:19:38,520 That's incredible. 561 00:19:38,520 --> 00:19:40,840 So we can actually learn about the composition 562 00:19:40,840 --> 00:19:43,120 of these distant planet's atmospheres 563 00:19:43,120 --> 00:19:45,240 from billions of miles away. 564 00:19:45,240 --> 00:19:46,600 It's pretty amazing, isn't it? 565 00:19:46,600 --> 00:19:48,880 And as our technology continues to improve, 566 00:19:48,880 --> 00:19:50,640 we're getting closer and closer to being 567 00:19:50,640 --> 00:19:53,000 able to actually see these planets directly. 568 00:19:53,000 --> 00:19:57,400 Imagine that, seeing another world with our own eyes, 569 00:19:57,400 --> 00:20:00,000 a world that might be teeming with life. 570 00:20:00,000 --> 00:20:02,000 It would be a truly revolutionary moment. 571 00:20:02,000 --> 00:20:03,560 It would change everything, wouldn't it? 572 00:20:03,560 --> 00:20:03,960 Yeah. 573 00:20:03,960 --> 00:20:06,480 Our whole understanding of our place in the universe. 574 00:20:06,480 --> 00:20:09,400 It would be a profound shift in perspective. 575 00:20:09,400 --> 00:20:12,280 To know that we're not alone, that life exists elsewhere 576 00:20:12,280 --> 00:20:14,480 in the cosmos, would be a discovery 577 00:20:14,480 --> 00:20:17,080 that would reverberate through all of humanity. 578 00:20:17,080 --> 00:20:20,160 Well, I, for one, am incredibly excited to see 579 00:20:20,160 --> 00:20:23,600 what the future holds for exoplanet research. 580 00:20:23,600 --> 00:20:26,400 Who knows what incredible discoveries await us out there? 581 00:20:26,400 --> 00:20:27,360 Indeed. 582 00:20:27,360 --> 00:20:29,800 And it's a reminder that the universe is full of wonder 583 00:20:29,800 --> 00:20:30,960 and possibility. 584 00:20:30,960 --> 00:20:33,600 From the mind-bending depths of black holes 585 00:20:33,600 --> 00:20:36,520 to the tantalizing promise of life beyond Earth, 586 00:20:36,520 --> 00:20:39,320 there's always something new to explore, always 587 00:20:39,320 --> 00:20:40,720 something new to learn. 588 00:20:40,720 --> 00:20:42,240 Well said. 589 00:20:42,240 --> 00:20:43,760 And on that note, I think it's time 590 00:20:43,760 --> 00:20:46,400 for us to wrap up this cosmic journey. 591 00:20:46,400 --> 00:20:49,000 It's been a truly awe-inspiring exploration 592 00:20:49,000 --> 00:20:51,360 of the universe, from the darkest corners 593 00:20:51,360 --> 00:20:52,600 to the brightest hopes. 594 00:20:52,600 --> 00:20:53,360 It has. 595 00:20:53,360 --> 00:20:55,880 And I want to thank everyone for joining us on this deep dive 596 00:20:55,880 --> 00:20:57,000 into the cosmos. 597 00:20:57,000 --> 00:20:58,560 If you've enjoyed this episode, be 598 00:20:58,560 --> 00:21:00,720 sure to subscribe to Cosmos in a pod 599 00:21:00,720 --> 00:21:03,280 so you don't miss our next adventure into the wonders 600 00:21:03,280 --> 00:21:04,760 of space and time. 601 00:21:04,760 --> 00:21:08,000 And remember, keep looking up, keep wondering, 602 00:21:08,000 --> 00:21:11,320 and never stop exploring the vast and mysterious universe. 603 00:21:11,320 --> 00:21:13,800 Until next time.