WEBVTT 00:00:00.000 --> 00:00:01.840 Okay, so let's unpack this. If you're trying 00:00:01.840 --> 00:00:04.540 to understand our place in the universe, or if 00:00:04.540 --> 00:00:06.440 you just need a reminder that science is really 00:00:06.440 --> 00:00:09.740 driven by wonder, there's one voice that, well, 00:00:09.859 --> 00:00:12.759 it just stands out. Carl Sagan. Carl Sagan. A 00:00:12.759 --> 00:00:14.679 voice that rings with, you know, equal parts 00:00:14.679 --> 00:00:17.460 enthusiasm and this really necessary skepticism. 00:00:17.620 --> 00:00:20.260 It's genuinely hard to overstate his impact. 00:00:20.519 --> 00:00:23.219 We are going to take a deep dive into the professional 00:00:23.219 --> 00:00:27.519 and profoundly personal journey of the man who 00:00:27.519 --> 00:00:29.780 became... I think you could argue the single 00:00:29.780 --> 00:00:32.119 most influential science communicator the world 00:00:32.119 --> 00:00:34.380 has ever known. And the numbers, they're just 00:00:34.380 --> 00:00:37.100 staggering. I mean, his 1980 television series, 00:00:37.240 --> 00:00:40.979 Cosmos, a personal voyage. Yeah. It was viewed 00:00:40.979 --> 00:00:44.590 by over 500 million people. across more than 00:00:44.590 --> 00:00:47.270 60 countries. Wow. That is a truly unprecedented 00:00:47.270 --> 00:00:50.429 global reach for a show about, you know, astrophysics 00:00:50.429 --> 00:00:52.950 and planetary science. And that reach, that immense 00:00:52.950 --> 00:00:55.130 celebrity that came with it, that really forms 00:00:55.130 --> 00:00:57.509 the core paradox of Carl Sagan's professional 00:00:57.509 --> 00:01:00.310 life. On one hand, you have this global icon, 00:01:00.649 --> 00:01:03.509 a Pulitzer Prize winner, the face of scientific 00:01:03.509 --> 00:01:06.650 humanism. But on the other, his reception back 00:01:06.650 --> 00:01:09.329 in the... the academic ivory tower, was much 00:01:09.329 --> 00:01:11.269 more polarized. Right. A lot of his scientific 00:01:11.269 --> 00:01:13.150 peers were deeply critical of him. They were. 00:01:13.269 --> 00:01:15.469 They saw him as too broad, maybe too much of 00:01:15.469 --> 00:01:18.269 a showman. Some even accused him of self -promotion 00:01:18.269 --> 00:01:21.430 instead of, you know, pure research. So our mission 00:01:21.430 --> 00:01:24.150 today is to connect those dots for you. We're 00:01:24.150 --> 00:01:27.370 going to synthesize his rigorous research. And, 00:01:27.390 --> 00:01:30.129 I mean, he published over 600 scientific papers. 00:01:30.390 --> 00:01:32.549 An incredible number. With his demanding role 00:01:32.549 --> 00:01:35.489 as this relentless public advocate for critical 00:01:35.489 --> 00:01:38.219 thinking. We want to show you exactly how his 00:01:38.219 --> 00:01:40.260 philosophical convictions and his scientific 00:01:40.260 --> 00:01:43.060 contributions were. Well, they were intertwined. 00:01:43.099 --> 00:01:46.040 And why his perspective remains so vital in our, 00:01:46.099 --> 00:01:48.439 you know, our information saturated world today. 00:01:48.540 --> 00:01:50.700 The central question we're really tackling is 00:01:50.700 --> 00:01:53.799 how did that Brooklyn kid born into a pretty 00:01:53.799 --> 00:01:55.760 modest family? His father was a garment worker. 00:01:56.200 --> 00:01:59.379 Exactly. A garment worker, his mother, a homemaker. 00:01:59.799 --> 00:02:02.920 How did he rise not only to become the David 00:02:02.920 --> 00:02:05.140 Duncan professor of astronomy at Cornell, but 00:02:05.140 --> 00:02:08.400 to achieve that level of profound global influence? 00:02:08.819 --> 00:02:10.860 It's a journey that was built on a foundation 00:02:10.860 --> 00:02:14.780 defined by this tension between intense curiosity 00:02:14.780 --> 00:02:17.840 and rigorous skepticism. Carl Edward Sagan, born 00:02:17.840 --> 00:02:21.819 in Bensonhurst, New York City, 1934. And his 00:02:21.819 --> 00:02:23.860 early life, you know, based in that modest urban 00:02:23.860 --> 00:02:26.199 apartment, it was really shaped by two parents 00:02:26.199 --> 00:02:28.500 who provided that perfect intellectual balance. 00:02:28.740 --> 00:02:31.340 That parental dynamic was absolutely crucial 00:02:31.340 --> 00:02:33.860 to his development. The family, they identified 00:02:33.860 --> 00:02:36.719 as Reform Jews. And while his father, Samuel, 00:02:36.879 --> 00:02:39.099 wasn't overly religious, his mother, Rachel, 00:02:39.259 --> 00:02:42.639 was very active in their temple and kept a kosher 00:02:42.639 --> 00:02:44.280 home. But it was more than that, right? It was 00:02:44.280 --> 00:02:45.800 about these two modes of thought he said they 00:02:45.800 --> 00:02:47.740 gave him. That's it. He spoke about it beautifully. 00:02:47.900 --> 00:02:50.259 He said his parents taught him the two uneasiness. 00:02:50.219 --> 00:02:52.439 cohabiting modes of thought that are central 00:02:52.439 --> 00:02:55.490 to the scientific method. Skepticism and wonder. 00:02:55.629 --> 00:02:58.930 Skepticism and wonder. Exactly. His father provided 00:02:58.930 --> 00:03:00.849 this example of, you know, practical empathy 00:03:00.849 --> 00:03:03.830 and social engagement. Samuel was known for helping 00:03:03.830 --> 00:03:07.349 the poor, mediating labor tensions. And his mother, 00:03:07.430 --> 00:03:10.669 Rachel, she provided the intense, rigorous analytical 00:03:10.669 --> 00:03:13.050 side. She was a frustrated intellectual, wasn't 00:03:13.050 --> 00:03:15.530 she? Absolutely. Her own ambitions were blocked 00:03:15.530 --> 00:03:17.689 by poverty and the social constraints of the 00:03:17.689 --> 00:03:20.409 era. And she just channeled all of that intellectual 00:03:20.409 --> 00:03:24.080 energy into nurturing Carl's curiosity. Biographers 00:03:24.080 --> 00:03:26.860 often say she worshipped her only son, believing 00:03:26.860 --> 00:03:29.159 he'd fulfill the dreams she couldn't. So you 00:03:29.159 --> 00:03:31.599 have this dual nature, the analytical rigor from 00:03:31.599 --> 00:03:34.199 his mother and this broad humanistic wonder from 00:03:34.199 --> 00:03:37.000 his father. And it all comes together in one 00:03:37.000 --> 00:03:39.400 definitive moment when he was just five years 00:03:39.400 --> 00:03:42.349 old. The solo trip to the public library. He 00:03:42.349 --> 00:03:44.250 was obsessed with a question that nobody in his 00:03:44.250 --> 00:03:46.389 circle could answer. What are the stars? And 00:03:46.389 --> 00:03:49.129 so armed with a library card, he goes and asks 00:03:49.129 --> 00:03:52.550 the librarian and the answer that the sun was 00:03:52.550 --> 00:03:54.349 a star that was just close and all the other 00:03:54.349 --> 00:03:56.669 stars were distant suns. It just stunned him. 00:03:56.789 --> 00:03:58.909 He called it a kind of religious experience. 00:03:58.990 --> 00:04:01.490 Yeah. I mean, for him, it wasn't just a fact. 00:04:01.569 --> 00:04:04.150 It was a total reordering of his personal universe. 00:04:04.370 --> 00:04:06.509 And that realization, that sense of infinite 00:04:06.509 --> 00:04:09.490 scale and possibility, it never left him. That 00:04:09.490 --> 00:04:12.169 moment was really the emotional fuel for everything 00:04:12.169 --> 00:04:15.270 he did afterward. And that sense of awe was cemented 00:04:15.270 --> 00:04:18.550 just a year later in 1939 at the New York World's 00:04:18.550 --> 00:04:21.310 Fair. He had these incredibly vivid memories 00:04:21.310 --> 00:04:23.670 of the exhibits, which to his young mind were 00:04:23.670 --> 00:04:26.269 just pure magic. Right, like the famous America 00:04:26.269 --> 00:04:28.949 of Tomorrow exhibit. With a moving map of a... 00:04:28.970 --> 00:04:32.009 future city, all highways and skyscrapers. But 00:04:32.009 --> 00:04:34.250 what really got him was the abstract science. 00:04:34.670 --> 00:04:37.250 He remembered seeing demos where a sound wave 00:04:37.250 --> 00:04:39.589 from a tuning fork would become a picture on 00:04:39.589 --> 00:04:42.529 an oscilloscope. Or how light shining on a photocell 00:04:42.529 --> 00:04:44.930 could create noise. And this is a really fascinating 00:04:44.930 --> 00:04:46.990 nugget for you to think about because it reveals 00:04:46.990 --> 00:04:49.129 the intellectual blueprint for his later work. 00:04:49.310 --> 00:04:51.970 He wrote about it, asking, how could a tone become 00:04:51.970 --> 00:04:55.069 a picture and light become a noise? So this obsession 00:04:55.069 --> 00:04:57.649 with converting signals was the origin of his 00:04:57.649 --> 00:05:00.569 lifelong interest in communication theory. signal 00:05:00.569 --> 00:05:03.470 intelligence, which was absolutely vital for 00:05:03.470 --> 00:05:06.730 his later work in SETI. And crucially, the fair 00:05:06.730 --> 00:05:10.420 heavily promoted the burial of a time capsule 00:05:10.420 --> 00:05:13.879 filled with 1930s mementos yeah so that exposure 00:05:13.879 --> 00:05:17.139 to the idea of packaging human civilization into 00:05:17.139 --> 00:05:19.779 a durable message for a future audience whether 00:05:19.779 --> 00:05:22.939 that's terrestrial or extraterrestrial that directly 00:05:22.939 --> 00:05:25.180 inspired his greatest public achievements the 00:05:25.180 --> 00:05:27.800 pioneer plaque and the voyager golden record 00:05:27.800 --> 00:05:30.800 exactly his childhood literally contained the 00:05:30.800 --> 00:05:32.939 seeds of his professional purpose and this is 00:05:32.939 --> 00:05:34.939 all happening against the backdrop of world war 00:05:34.939 --> 00:05:38.459 ii a deeply anxious time his parents were desperately 00:05:38.459 --> 00:05:40.300 worried about family caught in the Holocaust 00:05:40.300 --> 00:05:43.019 in Europe. His sister said their mother was fiercely 00:05:43.019 --> 00:05:45.079 protective of him, trying to shield him from 00:05:45.079 --> 00:05:48.000 those horrors. And Sagan reflected on this in 00:05:48.000 --> 00:05:50.319 The Demon Haunted World. He talked about that 00:05:50.319 --> 00:05:52.540 conflict between trying to keep that youthful, 00:05:52.560 --> 00:05:55.040 optimistic spirit while also confronting the 00:05:55.040 --> 00:05:57.139 brutal realities of what humanity is capable 00:05:57.139 --> 00:06:00.639 of. So moving into his education, he was recognized 00:06:00.639 --> 00:06:03.639 as exceptional very early on. Straight -A student 00:06:03.639 --> 00:06:06.160 at Raleigh High School in New Jersey, but, you 00:06:06.160 --> 00:06:09.199 know, consistently bored. His intellect was just 00:06:09.199 --> 00:06:12.680 undeniable. His teachers actually urged his parents 00:06:12.680 --> 00:06:15.199 to find a school for gifted children, but they 00:06:15.199 --> 00:06:17.459 just couldn't afford it. It was during his junior 00:06:17.459 --> 00:06:19.620 year that he realized astronomy wasn't just a 00:06:19.620 --> 00:06:22.199 hobby, it could be a paid career. And he didn't 00:06:22.199 --> 00:06:25.800 waste any time. He graduated in 51, voted most 00:06:25.800 --> 00:06:28.519 likely to succeed and was accepted into the University 00:06:28.519 --> 00:06:30.980 of Chicago's honors program at just 16. Yeah, 00:06:31.040 --> 00:06:33.139 that was partly due to the university chancellor's 00:06:33.139 --> 00:06:35.860 program that embraced the sort of ideal meritocracy 00:06:35.860 --> 00:06:38.899 with no strict age requirements. And his academic 00:06:38.899 --> 00:06:42.040 performance there was just. I mean, he racked 00:06:42.040 --> 00:06:44.480 up multiple degrees, a Bachelor of Liberal Arts 00:06:44.480 --> 00:06:47.720 in 54, a Bachelor of Science in Physics in 55. 00:06:48.060 --> 00:06:50.839 Then he does his graduate work immediately, submits 00:06:50.839 --> 00:06:52.860 his doctoral dissertation, Physical Studies of 00:06:52.860 --> 00:06:55.540 the Planets, and has his Ph .D. in Astronomy 00:06:55.540 --> 00:06:58.600 and Astrophysics by 1960. And he also worked 00:06:58.600 --> 00:07:00.600 on a thesis about the origins of life with the 00:07:00.600 --> 00:07:03.439 chemist Harold Urey. He did, which becomes important 00:07:03.439 --> 00:07:06.360 later. Speaking of his early work, we have to 00:07:06.360 --> 00:07:09.259 pause on this almost unbelievable fact that as 00:07:09.259 --> 00:07:12.660 a student, he was involved in classified, high 00:07:12.660 --> 00:07:15.759 -stakes military science. Tell us about Project 00:07:15.759 --> 00:07:19.819 A119. Right. Project A119 was a top -secret United 00:07:19.819 --> 00:07:23.500 States Air Force plan conceived in 1958 by a 00:07:23.500 --> 00:07:26.060 team that included Gerard Kuiper, who was actually 00:07:26.060 --> 00:07:28.459 Sagan's dissertation advisor. And the plan itself 00:07:28.459 --> 00:07:32.500 was just... terrifyingly simple. It was detonate 00:07:32.500 --> 00:07:34.819 a low yield nuclear warhead on the surface of 00:07:34.819 --> 00:07:36.959 the moon. And the purpose was just to show the 00:07:36.959 --> 00:07:39.139 Soviets we could do it. Precisely. It was a Cold 00:07:39.139 --> 00:07:42.060 War propaganda exercise, a visible, undeniable 00:07:42.060 --> 00:07:45.379 demonstration of military superiority meant to 00:07:45.379 --> 00:07:48.040 boost American morale and maybe intimidate the 00:07:48.040 --> 00:07:50.279 Soviet Union if they beat the U .S. to the moon. 00:07:50.399 --> 00:07:52.860 And Sagan was directly involved. He was. He worked 00:07:52.860 --> 00:07:54.939 on calculations about the expansion and visibility 00:07:54.939 --> 00:07:57.319 of the dust cloud that would result. He held 00:07:57.319 --> 00:07:59.019 a top secret clearance with the Air Force at 00:07:59.019 --> 00:08:00.990 the time. But the truly incredible part is the 00:08:00.990 --> 00:08:03.529 security breach that came out years later. Yes. 00:08:03.790 --> 00:08:06.970 The project was shelved. But Sagan, in 1959, 00:08:07.269 --> 00:08:09.550 when he was applying for a postdoctoral scholarship 00:08:09.550 --> 00:08:12.920 to UC Berkeley, He inadvertently included the 00:08:12.920 --> 00:08:15.959 classified titles of two Project A119 papers 00:08:15.959 --> 00:08:18.800 in his bibliography. The project director later 00:08:18.800 --> 00:08:21.939 confirmed that specific leak. And it just highlights 00:08:21.939 --> 00:08:24.740 this intense early conflict in his career, his 00:08:24.740 --> 00:08:27.180 deep involvement in secret Cold War military 00:08:27.180 --> 00:08:29.819 projects, which contrasts so sharply with his 00:08:29.819 --> 00:08:32.860 later public persona as an advocate for scientific 00:08:32.860 --> 00:08:35.820 transparency and international cooperation. So 00:08:35.820 --> 00:08:37.899 he moves from Chicago to a Miller Fellowship 00:08:37.899 --> 00:08:40.000 at Berkeley. consults for the Rand Corporation, 00:08:40.399 --> 00:08:42.340 and then gets an offer to lecture at Harvard. 00:08:42.500 --> 00:08:44.519 Which he successfully leveraged into an assistant 00:08:44.519 --> 00:08:46.879 professorship. He spent several productive years 00:08:46.879 --> 00:08:50.399 there in the 1960s. But then 1968 comes and it 00:08:50.399 --> 00:08:53.399 delivers this defining, really devastating professional 00:08:53.399 --> 00:08:56.200 blow. He was denied academic tenure at Harvard. 00:08:56.360 --> 00:08:58.159 This is a foundational moment we really have 00:08:58.159 --> 00:09:00.100 to unpack because it directly shaped the rest 00:09:00.100 --> 00:09:01.840 of his career. I mean, he was an active researcher, 00:09:02.120 --> 00:09:04.860 an advisor, a popular lecturer. So the denial 00:09:04.860 --> 00:09:07.059 was a huge personal surprise. It wasn't about 00:09:07.059 --> 00:09:09.379 a lack of research. It was about his approach 00:09:09.379 --> 00:09:12.519 to science. The critique was that he focused 00:09:12.519 --> 00:09:15.320 his interests too broadly. Instead of becoming 00:09:15.320 --> 00:09:18.240 a renowned expert in a narrow traditional specialty, 00:09:18.500 --> 00:09:21.230 which was the expectation at Harvard. That's 00:09:21.230 --> 00:09:23.389 the institutional critique. But there was a personal 00:09:23.389 --> 00:09:26.370 factor, too. There was. Nobel laureate Harold 00:09:26.370 --> 00:09:29.789 Urey, his former graduate mentor, wrote a deeply 00:09:29.789 --> 00:09:32.769 negative recommendation letter. Urey was what 00:09:32.769 --> 00:09:35.730 you'd call an old -time empiricist. He was very 00:09:35.730 --> 00:09:38.870 wary of grand theorizing. And he saw Sagan's 00:09:38.870 --> 00:09:41.970 willingness to speculate openly about the unknown, 00:09:42.149 --> 00:09:44.090 you know, about extraterrestrial life, about 00:09:44.090 --> 00:09:47.370 oceans on Europa. He saw that as a betrayal of 00:09:47.370 --> 00:09:51.580 scientific rigor. Exactly. that broad speculative 00:09:51.580 --> 00:09:53.779 approach combined with the perception of self 00:09:53.779 --> 00:09:55.779 -promotion from writing popular books and appearing 00:09:55.779 --> 00:09:58.279 on TV, it was just incompatible with their tenure 00:09:58.279 --> 00:09:59.919 standards. So you have to think about what this 00:09:59.919 --> 00:10:02.120 means. This wasn't just a rejection. It was a 00:10:02.120 --> 00:10:04.059 philosophical clash between two different ways 00:10:04.059 --> 00:10:06.840 of doing science. It was. And Harvard essentially 00:10:06.840 --> 00:10:09.080 forced Sagan into the public role he would later 00:10:09.080 --> 00:10:12.639 occupy. By rejecting the generalized big picture 00:10:12.639 --> 00:10:15.519 thinker who communicated widely, they ensured 00:10:15.519 --> 00:10:18.159 that he had to find his validation and his platform 00:10:18.159 --> 00:10:20.850 outside. that traditional academic structure. 00:10:21.070 --> 00:10:23.509 That denial must have been a bitter pill, but 00:10:23.509 --> 00:10:26.730 as the cliche goes, when one door closes. A planetary 00:10:26.730 --> 00:10:29.509 observatory opens. He was very quickly welcomed 00:10:29.509 --> 00:10:32.590 at Cornell University. Cornell, and particularly 00:10:32.590 --> 00:10:35.870 the department led by Thomas Gold, was just far 00:10:35.870 --> 00:10:38.990 more flexible, more forward -thinking. Gold understood 00:10:38.990 --> 00:10:41.750 that Sagan's growing public visibility was an 00:10:41.750 --> 00:10:44.279 asset. not a liability he was offered a full 00:10:44.279 --> 00:10:46.899 professorship a huge validation it was and he 00:10:46.899 --> 00:10:49.360 accepted it arriving in 1970 he would go on to 00:10:49.360 --> 00:10:51.899 spend nearly 30 years at cornell becoming the 00:10:51.899 --> 00:10:54.139 david duncan professor of astronomy and space 00:10:54.139 --> 00:10:56.899 sciences and directing the laboratory for planetary 00:10:56.899 --> 00:10:59.779 studies that environment allowed him to fully 00:10:59.779 --> 00:11:01.919 integrate his research with his public advocacy 00:11:01.919 --> 00:11:04.700 the very blend that harvard had explicitly rejected 00:11:05.419 --> 00:11:07.720 This move really created the Carl Sagan we all 00:11:07.720 --> 00:11:09.899 know today. So once he's established at Cornell, 00:11:10.200 --> 00:11:12.899 free to explore all these wide -ranging interests, 00:11:13.120 --> 00:11:16.600 his scientific contributions, despite the academic 00:11:16.600 --> 00:11:19.490 criticisms, were just foundational. especially 00:11:19.490 --> 00:11:21.990 in the emerging field of planetary science. He 00:11:21.990 --> 00:11:24.309 was defined by this. This was a major breakthrough, 00:11:24.470 --> 00:11:26.789 both technically and intellectually. And the 00:11:26.789 --> 00:11:29.009 crucial validation came very quickly with the 00:11:29.009 --> 00:11:32.269 NASA Mariner 2 mission in 1962, which confirmed 00:11:32.269 --> 00:11:34.610 his surface temperature calculation. And here's 00:11:34.610 --> 00:11:37.190 where his activist science really begins to emerge. 00:11:37.509 --> 00:11:40.389 He didn't just see Venus as some interesting 00:11:40.389 --> 00:11:44.289 remote world. No, he saw it as a natural laboratory 00:11:44.289 --> 00:11:47.409 providing a dire warning for Earth. He explicitly 00:11:47.409 --> 00:11:50.250 linked the. runaway greenhouse effect on Enos 00:11:50.250 --> 00:11:52.350 to the potential for man -made global warming 00:11:52.350 --> 00:11:54.450 right here. Which was revolutionary thinking 00:11:54.450 --> 00:11:56.850 in the 60s and 70s. It was. He was among the 00:11:56.850 --> 00:11:58.990 first highly visible scientists to take that 00:11:58.990 --> 00:12:01.529 complex atmospheric physics and apply it to a 00:12:01.529 --> 00:12:04.210 human -caused environmental crisis. And this 00:12:04.210 --> 00:12:06.669 led directly to him testifying before the U .S. 00:12:06.690 --> 00:12:09.929 Congress in 1985 about the dangers of unchecked 00:12:09.929 --> 00:12:12.490 greenhouse gas emissions. His knack for spotting 00:12:12.490 --> 00:12:14.809 potentially habitable environments extended further 00:12:14.809 --> 00:12:17.850 out too. To the moons of Jupiter and Saturn. 00:12:18.090 --> 00:12:21.690 Specifically, Titan, Saturn's largest moon. Sagan 00:12:21.690 --> 00:12:24.169 hypothesized that Titan might have oceans on 00:12:24.169 --> 00:12:27.549 its surface, not of water, but of liquid compounds 00:12:27.549 --> 00:12:31.129 like methane and ethane. He also identified that 00:12:31.129 --> 00:12:33.570 its reddish haze was probably caused by complex 00:12:33.570 --> 00:12:36.750 organic molecules, the precursors to life, constantly 00:12:36.750 --> 00:12:39.509 raining down. And maybe even more famously, Jupiter's 00:12:39.509 --> 00:12:42.710 moon, Europa. Right. His hypothesis that Europa 00:12:42.710 --> 00:12:45.470 might possess subsurface oceans of liquid water 00:12:45.470 --> 00:12:48.690 kept warm by tidal heating made it a prime candidate 00:12:48.690 --> 00:12:51.370 for a habitable environment. A hypothesis that 00:12:51.370 --> 00:12:54.190 was later indirectly validated by the Galileo 00:12:54.190 --> 00:12:56.669 spacecraft data, which showed evidence of liquid 00:12:56.669 --> 00:12:58.570 under that ice crust. And it just illustrates 00:12:58.570 --> 00:13:00.450 his gift. He was always spotting the environments, 00:13:00.570 --> 00:13:02.450 the places where the chemistry of life, even 00:13:02.450 --> 00:13:04.889 under extreme conditions, might just find a foothold. 00:13:05.009 --> 00:13:07.970 His work on Mars was equally significant in steering 00:13:07.970 --> 00:13:10.379 the science away from romantic speculation. and 00:13:10.379 --> 00:13:12.840 toward rigor. For decades, people had argued 00:13:12.840 --> 00:13:14.539 that the shifting colors on the Martian surface 00:13:14.539 --> 00:13:17.480 were signs of seasons or even vegetation. And 00:13:17.480 --> 00:13:20.419 Sagan proved otherwise. He correctly determined 00:13:20.419 --> 00:13:22.539 that those variations were simply the movement 00:13:22.539 --> 00:13:25.299 of fine -grained surface dust shifted around 00:13:25.299 --> 00:13:28.120 by these immense high -speed Martian windstorms. 00:13:28.120 --> 00:13:31.320 So he demoted these beautiful, mysterious changes 00:13:31.320 --> 00:13:35.460 to just geology and meteorology. Applying skepticism 00:13:35.460 --> 00:13:38.500 to romantic speculation once again. And this 00:13:38.500 --> 00:13:41.700 rigor extended to the very origins of life. He's 00:13:41.700 --> 00:13:44.460 recognized as a pioneer in exobiology, or as 00:13:44.460 --> 00:13:47.080 we call it now, astrobiology. He did practical 00:13:47.080 --> 00:13:49.019 experiments, right? Absolutely. He demonstrated 00:13:49.019 --> 00:13:51.480 in the lab that amino acids, the fundamental 00:13:51.480 --> 00:13:54.320 building blocks of life, could be produced just 00:13:54.320 --> 00:13:57.080 by exposing basic chemical components to energy 00:13:57.080 --> 00:13:59.779 sources like radiation. He was showing that the 00:13:59.779 --> 00:14:02.039 spontaneous origin of life's basic chemistry 00:14:02.039 --> 00:14:04.879 was chemically plausible under the violent conditions 00:14:04.879 --> 00:14:06.980 of early planets. And this leads us directly 00:14:06.980 --> 00:14:09.460 to the search for extraterrestrial intelligence, 00:14:09.700 --> 00:14:12.509 or SETI. This was still considered a fringe pursuit 00:14:12.509 --> 00:14:15.090 by a lot of academics. But Sagan worked tirelessly 00:14:15.090 --> 00:14:17.649 to give it respectability. He approached SETI 00:14:17.649 --> 00:14:19.970 not as science fiction, but as radio astronomy, 00:14:20.269 --> 00:14:23.090 a signal detection problem. His credibility was 00:14:23.090 --> 00:14:25.549 such that he's still the most cited SETI scientist. 00:14:25.889 --> 00:14:29.759 But the real game changer was his advocacy. The 00:14:29.759 --> 00:14:32.419 petition published in Science in 1982 is a perfect 00:14:32.419 --> 00:14:35.559 example. He leveraged all of his scientific and 00:14:35.559 --> 00:14:38.200 social capital. He convinced 70 highly respected 00:14:38.200 --> 00:14:41.019 scientists, including seven Nobel laureates, 00:14:41.039 --> 00:14:43.600 to sign a petition advocating for the validity 00:14:43.600 --> 00:14:46.379 of SETI research. And publishing that in a flagship 00:14:46.379 --> 00:14:49.539 journal like Science was a powerful public statement. 00:14:49.659 --> 00:14:52.620 It vastly increased the field's academic respectability. 00:14:52.980 --> 00:14:55.100 But the work he's most famously remembered for 00:14:55.100 --> 00:14:57.899 in this area involves the physical messages he 00:14:57.899 --> 00:15:01.090 helped send into space. True interstellar artifacts. 00:15:01.529 --> 00:15:04.429 These were designed as durable, redundant time 00:15:04.429 --> 00:15:07.169 capsules. The idea was they had to be understandable 00:15:07.169 --> 00:15:09.529 by an intelligence completely unlike our own, 00:15:09.549 --> 00:15:11.570 maybe millennia in the future. The first one 00:15:11.570 --> 00:15:13.830 was the Pioneer plaque. Attached to the Pioneer 00:15:13.830 --> 00:15:17.669 10 and 11 probes, launched in 72 and 73, it was 00:15:17.669 --> 00:15:20.149 a gold anodized aluminum plaque, and it was an 00:15:20.149 --> 00:15:22.710 exercise in pure scientific communication. What 00:15:22.710 --> 00:15:25.259 specifically did they include? It showed a diagram 00:15:25.259 --> 00:15:27.740 of the hydrogen atom's hyperfine transition, 00:15:28.059 --> 00:15:31.679 a universal standard of distance and time. It 00:15:31.679 --> 00:15:33.620 showed the figures of a man and a woman next 00:15:33.620 --> 00:15:36.519 to the spacecraft for scale, and a map showing 00:15:36.519 --> 00:15:39.700 Earth's position relative to 14 known pulsars. 00:15:39.899 --> 00:15:42.179 Right, the pulsars act like galactic lighthouses. 00:15:42.379 --> 00:15:45.580 Exactly. They pulse at rates that change predictably 00:15:45.580 --> 00:15:48.639 over cosmic timescales, so any finder could determine 00:15:48.639 --> 00:15:51.419 when the Pioneer probe was launched. Incredible 00:15:51.419 --> 00:15:54.879 precision, packed onto a tiny metal plate. And 00:15:54.879 --> 00:15:57.120 the next message, with the Voyager probes in 00:15:57.120 --> 00:16:01.059 1977, was even more ambitious the voyager golden 00:16:01.059 --> 00:16:03.659 record this was his ultimate communication challenge 00:16:03.659 --> 00:16:06.100 co -curated with a team that included his third 00:16:06.100 --> 00:16:09.279 wife and drew in a 12 -inch gold -plated copper 00:16:09.279 --> 00:16:12.279 phonograph record A summary of Earth's diversity. 00:16:12.580 --> 00:16:15.679 It contained 115 images, sounds of Earth whales, 00:16:16.039 --> 00:16:18.299 volcanoes, the wind, and 90 minutes of music 00:16:18.299 --> 00:16:20.700 from across cultures, plus spoken greetings in 00:16:20.700 --> 00:16:23.120 55 languages. And it wasn't just showing off. 00:16:23.279 --> 00:16:25.399 It was about conveying essential facts of geometry, 00:16:25.580 --> 00:16:28.019 chemistry, and our location in a universally 00:16:28.019 --> 00:16:30.240 intelligible format. And while those records 00:16:30.240 --> 00:16:32.600 are still traveling, he also helped write a non 00:16:32.600 --> 00:16:35.480 -physical message. The Arecibo radio message 00:16:35.480 --> 00:16:39.759 beamed into space in 1974. He helped Frank Drake 00:16:39.759 --> 00:16:42.139 write that transmission. Which was basically 00:16:42.139 --> 00:16:45.700 a short, coded blast of binary info. Pure symbolic 00:16:45.700 --> 00:16:48.740 logic put into a radio wave, conveying information 00:16:48.740 --> 00:16:52.299 about human DNA, the solar system, and the Arecibo 00:16:52.299 --> 00:16:54.980 antenna itself. His proximity to the space program 00:16:54.980 --> 00:16:58.080 was just constant. He was an advisor to NASA 00:16:58.080 --> 00:17:00.980 from the 50s onward, briefing the Apollo astronauts 00:17:00.980 --> 00:17:03.269 before their flights to the moon. He was deeply 00:17:03.269 --> 00:17:05.690 embedded in mission planning, but he also wasn't 00:17:05.690 --> 00:17:08.250 afraid to challenge NASA's priorities. Later 00:17:08.250 --> 00:17:10.170 in his career, he often argued that the excessive 00:17:10.170 --> 00:17:13.170 funding for the space shuttle and the ISS came 00:17:13.170 --> 00:17:15.410 at the expense of what he believed was more scientifically 00:17:15.410 --> 00:17:18.549 valuable. Which was? Unmanned robotic planetary 00:17:18.549 --> 00:17:21.250 exploration. He was always, always advocating 00:17:21.250 --> 00:17:23.509 for the science, not just the showmanship. So 00:17:23.509 --> 00:17:25.869 by the time the 1980s arrived, Sagan had already 00:17:25.869 --> 00:17:27.849 won the Pulitzer for the Dragons of Eden and 00:17:27.849 --> 00:17:30.609 established his scientific reputation. But it 00:17:30.609 --> 00:17:32.259 was television that just trained him. transformed 00:17:32.259 --> 00:17:35.579 him from a famous scientist into this irreversible 00:17:35.579 --> 00:17:38.299 global cultural phenomenon. The vehicle, of course, 00:17:38.380 --> 00:17:41.500 was Cosmos, a personal voyage. Premiering in 00:17:41.500 --> 00:17:45.140 1980, the 13 -part PBS series, which he co -wrote 00:17:45.140 --> 00:17:47.859 and narrated, was just a masterpiece of scientific 00:17:47.859 --> 00:17:50.279 outreach. It wasn't just popular. It completely 00:17:50.279 --> 00:17:53.339 redefined how science could be presented on screen. 00:17:53.599 --> 00:17:56.279 It became the most watched series in American 00:17:56.279 --> 00:17:59.539 public television history until 1990. And his 00:17:59.539 --> 00:18:01.779 motivation was deeply rooted in his frustration 00:18:01.779 --> 00:18:04.480 with the status quo. He was targeting a general 00:18:04.480 --> 00:18:06.519 audience because he felt the average person had 00:18:06.519 --> 00:18:08.720 lost interest in science because of what he called 00:18:08.720 --> 00:18:11.859 a stifled educational system. So Cosmos was designed 00:18:11.859 --> 00:18:14.440 to reignite that childhood wonder he felt in 00:18:14.440 --> 00:18:16.819 the library. Exactly. And they used incredibly 00:18:16.819 --> 00:18:19.000 innovative techniques like the cosmic calendar, 00:18:19.240 --> 00:18:22.339 which condenses the 13 .8 billion year history 00:18:22.339 --> 00:18:25.140 of the universe into a single Earth year. That 00:18:25.140 --> 00:18:27.200 remains a touchstone for science communicators 00:18:27.200 --> 00:18:29.539 today. The show blended cutting edge science, 00:18:29.779 --> 00:18:32.279 pioneering special effects for the time, and 00:18:32.279 --> 00:18:35.099 this profound philosophical narrative. And Sagan 00:18:35.099 --> 00:18:37.420 was the viewer's earnest, trustworthy guide through 00:18:37.420 --> 00:18:40.369 it all. The accolades were immediate. Two Emmys, 00:18:40.470 --> 00:18:44.009 a Peabody, a Hugo Award. Time magazine put him 00:18:44.009 --> 00:18:46.269 on their cover. He had arrived as a cultural 00:18:46.269 --> 00:18:48.369 superstar. The thing that made him instantly 00:18:48.369 --> 00:18:51.730 recognizable, though, was his delivery. That 00:18:51.730 --> 00:18:54.250 measured slightly breathy and highly emphatic 00:18:54.250 --> 00:18:56.930 way of speaking, which also led to the single 00:18:56.930 --> 00:19:00.009 most famous misquote in science history. Billions 00:19:00.009 --> 00:19:01.750 and billions. Billions and billions. Which is 00:19:01.750 --> 00:19:03.950 a fun detail because he never actually used that 00:19:03.950 --> 00:19:06.869 exact phrase in Cosmos. He preferred the slightly 00:19:06.869 --> 00:19:09.809 more dramatic billions upon billions. But the 00:19:09.809 --> 00:19:12.750 parody stuck mostly thanks to his unique verbal 00:19:12.750 --> 00:19:16.269 emphasis. We know he consciously emphasized the 00:19:16.269 --> 00:19:19.470 B sound when saying billions so people wouldn't 00:19:19.470 --> 00:19:21.609 mishear it as millions. And that distinctive 00:19:21.609 --> 00:19:24.430 cadence made him irresistible to comedians. The 00:19:24.430 --> 00:19:26.390 most famous, of course, was Johnny Carson on 00:19:26.390 --> 00:19:28.589 The Tonight Show. And his impression became iconic. 00:19:29.349 --> 00:19:31.450 But what's fascinating is that Sagan took this 00:19:31.450 --> 00:19:34.509 mockery in stride. He even titled his final book 00:19:34.509 --> 00:19:37.269 Billions and Billions and started it with a humorous 00:19:37.269 --> 00:19:39.690 discussion of the phrase's history. He actually 00:19:39.690 --> 00:19:42.170 noted that Carson, who was an amateur astronomer 00:19:42.170 --> 00:19:45.170 himself, was quite clever. And his caricature 00:19:45.170 --> 00:19:48.029 often included a surprising amount of real, accurate 00:19:48.029 --> 00:19:51.009 science. The popularity was so immense that, 00:19:51.089 --> 00:19:54.500 humorously, a Sagan. became defined in scientific 00:19:54.500 --> 00:19:57.339 circles as an informal unit of measurement for 00:19:57.339 --> 00:20:00.559 any very large number of anything. Beyond television, 00:20:00.720 --> 00:20:02.819 his output of popular science books was just 00:20:02.819 --> 00:20:05.759 immense. The Dragons of Eden, about the evolution 00:20:05.759 --> 00:20:09.259 of human intelligence, won him the 1978 Pulitzer. 00:20:09.819 --> 00:20:12.579 He also wrote classics like Broca's Brain and 00:20:12.579 --> 00:20:14.519 The Demon -Haunted World. And we can't forget 00:20:14.519 --> 00:20:16.880 he dipped his toe into fiction once, the science 00:20:16.880 --> 00:20:19.630 fiction novel Contact. Published in 1985, it 00:20:19.630 --> 00:20:21.470 was based on a film treatment he co -wrote with 00:20:21.470 --> 00:20:24.190 Andrian, and it was later adapted into that highly 00:20:24.190 --> 00:20:27.690 successful 1997 film starring Jodie Foster. The 00:20:27.690 --> 00:20:30.730 film itself won a Hugo Award. But maybe his single 00:20:30.730 --> 00:20:33.130 most enduring and powerful piece of philosophical 00:20:33.130 --> 00:20:35.769 rhetoric is the famous pale blue dot reflection. 00:20:36.210 --> 00:20:38.529 And this moment was born from his direct request 00:20:38.529 --> 00:20:42.769 to NASA. Yes. In 1990, at Sagan's urging, the 00:20:42.769 --> 00:20:45.410 Voyager 1 spacecraft, having finished its primary 00:20:45.410 --> 00:20:48.230 mission, turned its camera back toward Earth 00:20:48.230 --> 00:20:51.490 from a distance of 6 billion kilometers. And 00:20:51.490 --> 00:20:54.009 the resulting photo showed Earth as just a single 00:20:54.009 --> 00:20:57.910 tiny bright pixel, a literal mote of dust suspended 00:20:57.910 --> 00:21:01.230 in a sunbeam. His 1994 lecture based on this 00:21:01.230 --> 00:21:03.150 image and the book that followed, Pale Blue Dot, 00:21:03.349 --> 00:21:05.609 it's often taught in philosophy classes, not 00:21:05.609 --> 00:21:07.990 just science courses. The rhetorical power is 00:21:07.990 --> 00:21:11.109 immense. He used that image of human insignificance 00:21:11.109 --> 00:21:13.589 to deliver this powerful moral message about 00:21:13.589 --> 00:21:16.309 the petty nature of human conflict. Think of 00:21:16.309 --> 00:21:18.430 the rivers of blood spawned by all those generals 00:21:18.430 --> 00:21:21.410 and emperors so that in glory and triumph, they 00:21:21.410 --> 00:21:23.509 could become the momentary masters of a fraction 00:21:23.509 --> 00:21:25.730 of a dot. And that perspective links directly 00:21:25.730 --> 00:21:28.019 back to the five -year -old in the library. For 00:21:28.019 --> 00:21:30.500 Sagan, grasping the scale of the cosmos should 00:21:30.500 --> 00:21:33.460 logically lead to profound humility, and that 00:21:33.460 --> 00:21:35.240 humility should compel us to treat one another 00:21:35.240 --> 00:21:37.440 and our planet with kindness, given that this 00:21:37.440 --> 00:21:40.019 tiny distant dot is the only home we have ever 00:21:40.019 --> 00:21:42.799 known. His science was the foundation for his 00:21:42.799 --> 00:21:45.420 morality and his activism. That link between 00:21:45.420 --> 00:21:48.940 cosmic perspective and global morality really 00:21:48.940 --> 00:21:52.880 defines his final decades. Seguin was never content 00:21:52.880 --> 00:21:55.519 just to observe the universe. He felt he had 00:21:55.519 --> 00:21:58.240 to actively address the major problems on our 00:21:58.240 --> 00:22:00.960 mote of dust. His scientific rigor often crossed 00:22:00.960 --> 00:22:03.500 directly into political activism, and it was 00:22:03.500 --> 00:22:06.440 driven by this deep, constant concern over humanity's 00:22:06.440 --> 00:22:08.839 capacity for self -destruction, a concern he 00:22:08.839 --> 00:22:11.440 often linked back to his thoughts on the Fermi 00:22:11.440 --> 00:22:13.880 paradox. Right, the idea that maybe advanced 00:22:13.880 --> 00:22:16.099 civilizations just destroy themselves before 00:22:16.099 --> 00:22:18.720 they can reach the stars. And that fear fueled 00:22:18.720 --> 00:22:20.880 his most high -profile political engagement. 00:22:20.940 --> 00:22:23.740 The nuclear winter hypothesis, this was at the 00:22:23.740 --> 00:22:26.819 absolute height of Cold War anxiety in the 1980s. 00:22:26.839 --> 00:22:29.299 He became deeply involved in developing and publicizing 00:22:29.299 --> 00:22:32.599 what was called the TTIPS model in 1983. So for 00:22:32.599 --> 00:22:34.579 our audience, what exactly was the TTIPS model 00:22:34.579 --> 00:22:37.019 and what did it predict? Well, TTIPS was an acronym 00:22:37.019 --> 00:22:40.039 for the authors Turco, Toon, Ackerman, Pollack, 00:22:40.079 --> 00:22:42.519 and Sagan. The model predicted that a massive 00:22:42.519 --> 00:22:44.640 nuclear exchange would inject vast amounts of 00:22:44.640 --> 00:22:47.980 dust, and crucially, soot from urban firestorms 00:22:47.980 --> 00:22:50.039 into the upper atmosphere. And that soot and 00:22:50.039 --> 00:22:52.359 dust would block out the sun. It would rise high 00:22:52.359 --> 00:22:54.960 enough to absorb and scatter incoming sunlight. 00:22:55.200 --> 00:22:58.279 This layer would create an optical depth that 00:22:58.279 --> 00:23:00.460 would plunge the Earth into prolonged darkness 00:23:00.460 --> 00:23:03.579 and freezing temperatures. A global winter. The 00:23:03.579 --> 00:23:06.980 prediction was for cooling far more intense and 00:23:06.980 --> 00:23:09.640 prolonged than simple dust would cause, leading 00:23:09.640 --> 00:23:12.680 to catastrophic agricultural failure, global 00:23:12.680 --> 00:23:15.680 starvation, even for nations not directly involved 00:23:15.680 --> 00:23:18.710 in the war. And Sagan used his immense media 00:23:18.710 --> 00:23:21.170 platform to get this information out, making 00:23:21.170 --> 00:23:23.369 him a central figure in the anti -nuclear movement. 00:23:23.650 --> 00:23:26.230 But this level of advocacy generated a massive 00:23:26.230 --> 00:23:29.369 backlash from his peers. It did. Many in the 00:23:29.369 --> 00:23:31.490 scientific community felt he was overstating 00:23:31.490 --> 00:23:33.410 the certainty of the model for political ends. 00:23:33.670 --> 00:23:36.750 He faced really serious public disdain, especially 00:23:36.750 --> 00:23:39.190 from hardline figures like the nuclear physicist 00:23:39.190 --> 00:23:41.869 Edward Teller. The father of the H -bomb. Teller's 00:23:41.869 --> 00:23:44.190 critique was scathing. He basically called Sagan 00:23:44.190 --> 00:23:46.789 a sensationalist. He said, A propagandist is 00:23:46.789 --> 00:23:49.069 one who uses incomplete information to produce 00:23:49.069 --> 00:23:51.849 maximum persuasion. I can compliment you on being 00:23:51.849 --> 00:23:54.809 indeed an excellent propagandist. It was a very 00:23:54.809 --> 00:23:57.809 public, very high stakes battle. Sagan and his 00:23:57.809 --> 00:24:00.130 colleagues later slightly revised the severity 00:24:00.130 --> 00:24:02.190 of the cooling down to nuclear autumn. But the 00:24:02.190 --> 00:24:05.230 core concept that a limited nuclear exchange 00:24:05.230 --> 00:24:08.210 could devastate the global climate that held. 00:24:08.329 --> 00:24:11.849 And his integrity was tested again in 1991 during 00:24:11.849 --> 00:24:14.579 the Gulf War. Saddam Hussein threatened to light 00:24:14.579 --> 00:24:17.220 Kuwait's oil wells on fire, and Sagan and his 00:24:17.220 --> 00:24:19.539 team warned that if those fires burned for months, 00:24:19.660 --> 00:24:21.960 the smoke could disrupt agriculture in South 00:24:21.960 --> 00:24:25.200 Asia. The fires did burn for months and the prediction 00:24:25.200 --> 00:24:27.420 became a subject of heated scientific debate. 00:24:27.779 --> 00:24:30.220 And to his eternal credit, when he reviewed the 00:24:30.220 --> 00:24:33.059 data later, Sagan publicly conceded that he had 00:24:33.059 --> 00:24:35.019 been partially wrong about the global effects. 00:24:35.279 --> 00:24:37.500 In the demon haunted world, he noted that while 00:24:37.500 --> 00:24:39.920 local temperatures did drop by four to six degrees 00:24:39.920 --> 00:24:42.599 Celsius over the Persian Gulf, the smoke didn't 00:24:42.599 --> 00:24:44.700 reach the crucial stratospheric altitudes they 00:24:44.700 --> 00:24:47.150 had predicted. So Asia was spared the continental 00:24:47.150 --> 00:24:49.789 cooling effect. And that intellectual honesty, 00:24:50.069 --> 00:24:52.750 the willingness to admit error when new data 00:24:52.750 --> 00:24:55.589 contradicted his prediction, even after a huge 00:24:55.589 --> 00:24:58.690 public debate, that's critical. It distinguished 00:24:58.690 --> 00:25:01.890 his activism from mere propaganda. He applied 00:25:01.890 --> 00:25:04.230 the same rigor to his own claims as he did to 00:25:04.230 --> 00:25:07.390 anyone else's. Shifting back to space, he was 00:25:07.390 --> 00:25:09.750 a vocal proponent for an organized search for 00:25:09.750 --> 00:25:12.849 near -Earth objects, or NEOs, that pose an impact 00:25:12.849 --> 00:25:15.779 threat. But here, too, he saw a dangerous political 00:25:15.779 --> 00:25:18.240 dilemma. This is what he called the deflection 00:25:18.240 --> 00:25:21.109 dilemma. He argued that the very technology you'd 00:25:21.109 --> 00:25:23.329 need to safely deflect a threatening asteroid 00:25:23.329 --> 00:25:26.109 away from Earth, say, a pretext delivery system 00:25:26.109 --> 00:25:28.970 with a nuclear detonation in the hands of a hostile 00:25:28.970 --> 00:25:31.730 power that could be used to divert a non -threatening 00:25:31.730 --> 00:25:34.250 object toward Earth. Exactly. The global defense 00:25:34.250 --> 00:25:36.490 mechanism becomes the ultimate weapon of mass 00:25:36.490 --> 00:25:39.049 destruction. So he saw this double edged sword 00:25:39.049 --> 00:25:41.829 as a catalyst for political reform. He did. He 00:25:41.829 --> 00:25:44.150 argued that the existence of this dual use technology 00:25:44.150 --> 00:25:46.690 required international accountability and oversight, 00:25:47.009 --> 00:25:53.059 forcing maturing. And at the root of all of his 00:25:53.059 --> 00:25:56.160 work, both scientific and political, was this 00:25:56.160 --> 00:25:59.420 almost missionary commitment to skeptical inquiry. 00:26:00.119 --> 00:26:03.619 He wanted everyone, not just academics, to adopt 00:26:03.619 --> 00:26:06.799 the tools of science. This is the driving force 00:26:06.799 --> 00:26:09.900 behind his famous baloney detection kit, a set 00:26:09.900 --> 00:26:11.940 of tools he laid out in the demon -haunted world 00:26:11.940 --> 00:26:14.460 for critical thinking. It was designed to defend 00:26:14.460 --> 00:26:17.319 against pervasive pseudoscience, superstition, 00:26:17.339 --> 00:26:20.259 and faulty reasoning. And central to this kit 00:26:20.259 --> 00:26:22.980 is the dictum that is now universally known as 00:26:22.980 --> 00:26:25.660 the Sagan Standard. extraordinary claims require 00:26:25.660 --> 00:26:28.339 extraordinary evidence. It is the single most 00:26:28.339 --> 00:26:31.039 quotable summary of scientific skepticism. And 00:26:31.039 --> 00:26:32.480 what's a great nugget for you, the listener, 00:26:32.640 --> 00:26:34.700 is the intellectual lineage of that standard. 00:26:35.319 --> 00:26:37.700 Sagan popularized it, but the concept is much 00:26:37.700 --> 00:26:40.119 older. Indeed. You can trace it through figures 00:26:40.119 --> 00:26:42.640 like sociologist Marcello Truzzi in the 70s, 00:26:42.640 --> 00:26:45.000 but its purest form is the principle of Laplace 00:26:45.000 --> 00:26:48.000 from the early 19th century. Pierre Simon Laplace 00:26:48.000 --> 00:26:50.079 stated, the weight of the evidence should be 00:26:50.079 --> 00:26:52.000 proportioned to the strangeness of the facts. 00:26:52.509 --> 00:26:55.269 Sagan just took that rigorous standard and made 00:26:55.269 --> 00:26:57.769 it accessible and memorable for the entire world. 00:26:57.930 --> 00:27:01.069 And he applied that skepticism ruthlessly, even 00:27:01.069 --> 00:27:03.309 against historical giants like Plato. His critique 00:27:03.309 --> 00:27:05.960 of Plato was profound. It was a critique of the 00:27:05.960 --> 00:27:09.000 historical separation of mind and matter. Sagan 00:27:09.000 --> 00:27:10.960 criticized Plato for believing that abstract 00:27:10.960 --> 00:27:13.720 ideas were far more real than the natural world 00:27:13.720 --> 00:27:16.420 and, crucially, for advising astronomers not 00:27:16.420 --> 00:27:18.920 to observe the stars and planets. He felt this 00:27:18.920 --> 00:27:22.140 platonic disdain for empirical observation basically 00:27:22.140 --> 00:27:24.559 extinguished the light of science and experiment 00:27:24.559 --> 00:27:27.180 that had been briefly kindled by earlier Greek 00:27:27.180 --> 00:27:30.480 materialist thinkers. For Sagan, science was 00:27:30.480 --> 00:27:33.319 observation and testing. not just abstract thought. 00:27:33.480 --> 00:27:35.539 And applying that skepticism to the modern world, 00:27:35.619 --> 00:27:37.819 let's talk about UFOs. He was personally fascinated 00:27:37.819 --> 00:27:41.019 by the 1947 flying saucer craze as a young man. 00:27:41.180 --> 00:27:43.460 But his adult scientific view was consistently 00:27:43.460 --> 00:27:47.119 skeptical, yet nuanced. Very nuanced. He strongly 00:27:47.119 --> 00:27:49.539 rejected the prevailing extraterrestrial explanations 00:27:49.539 --> 00:27:52.680 for UFOs. He argued there was simply no physical 00:27:52.680 --> 00:27:55.630 evidence that met the Sagan standard. However, 00:27:55.809 --> 00:27:58.069 he believed the phenomenon was a completely legitimate 00:27:58.069 --> 00:28:00.670 subject for scientific study, mainly because 00:28:00.670 --> 00:28:03.650 of the massive public interest. He urged the 00:28:03.650 --> 00:28:06.670 government to declassify all files, stressed 00:28:06.670 --> 00:28:09.349 that transparency was key. But he cautioned against 00:28:09.349 --> 00:28:11.549 jumping to the conclusion that the files contained 00:28:11.549 --> 00:28:14.750 suppressed evidence of alien visits. Finally, 00:28:14.769 --> 00:28:16.930 let's turn to his complex and sometimes surprising 00:28:16.930 --> 00:28:19.630 personal beliefs, beginning with his views on 00:28:19.630 --> 00:28:40.829 spirituality and God. His preferred concept leaned 00:28:40.829 --> 00:28:43.369 more toward philosophical naturalism, echoing 00:28:43.369 --> 00:28:46.430 thinkers like Spinoza and Einstein. Right. He 00:28:46.430 --> 00:28:49.630 viewed God as essentially the sum total of the 00:28:49.630 --> 00:28:52.410 physical laws which describe the universe. But 00:28:52.410 --> 00:28:54.250 he acknowledged the emotional shortcoming of 00:28:54.250 --> 00:28:57.109 that view. He famously added that this God is 00:28:57.109 --> 00:28:59.799 emotionally unsatisfying. It does not make much 00:28:59.799 --> 00:29:02.599 sense to pray to the law of gravity. Yet he believes 00:29:02.599 --> 00:29:04.799 science itself could be a source of spirituality. 00:29:04.880 --> 00:29:08.220 A profound source of spirituality, he called 00:29:08.220 --> 00:29:11.740 it, rooted in that overwhelming sense of elation 00:29:11.740 --> 00:29:15.319 and humility combined when one grasps the true 00:29:15.319 --> 00:29:18.119 scale of the cosmos. And then there's the most 00:29:18.119 --> 00:29:20.559 surprising personal revelation, which we only 00:29:20.559 --> 00:29:23.230 learn about after his death. His longstanding 00:29:23.230 --> 00:29:26.450 advocacy for the use of marijuana published anonymously 00:29:26.450 --> 00:29:29.730 as Mr. X. This was in 1971 in the book Marijuana 00:29:29.730 --> 00:29:32.089 Reconsidered, and he published anonymously precisely 00:29:32.089 --> 00:29:35.150 because of the academic climate. In 71, admitting 00:29:35.150 --> 00:29:37.089 to cannabis use would have instantly destroyed 00:29:37.089 --> 00:29:39.230 the credibility he was trying so hard to build. 00:29:39.349 --> 00:29:41.730 Especially after the Harvard tenure debate. Exactly. 00:29:42.170 --> 00:29:44.730 As Mr. X, he claimed that cannabis was a tool 00:29:44.730 --> 00:29:47.529 for intellectual and sensual enhancement. He 00:29:47.529 --> 00:29:50.170 said it helped him appreciate art, enhance intellectual 00:29:50.170 --> 00:29:53.170 experiences, and even provided inspiration for 00:29:53.170 --> 00:29:55.569 some of his scientific work by allowing him to 00:29:55.569 --> 00:29:57.430 see connections and patterns he might otherwise 00:29:57.430 --> 00:30:00.170 miss. This revelation just adds this crucial 00:30:00.170 --> 00:30:03.230 depth to the portrait of Sagan as a constant 00:30:03.230 --> 00:30:06.299 intellectual explorer. willing to risk professional 00:30:06.299 --> 00:30:09.140 scorn for the sake of expanded experience. And 00:30:09.140 --> 00:30:11.140 the connection is cemented by the fact that after 00:30:11.140 --> 00:30:13.359 his identity was revealed by his friend Lester 00:30:13.359 --> 00:30:16.099 Grinspoon following his death, his widow, Ann 00:30:16.099 --> 00:30:18.539 Druyan, went on to preside over the board of 00:30:18.539 --> 00:30:21.000 directors for NORML, the National Organization 00:30:21.000 --> 00:30:24.059 for the Reform of Marijuana Laws. Carl Sagan 00:30:24.059 --> 00:30:27.319 died in 1996. He was relatively young, only 62. 00:30:27.619 --> 00:30:29.980 He succumbed to pneumonia after a brutal battle 00:30:29.980 --> 00:30:32.579 with myelodysplasia, a type of bone marrow cancer. 00:30:32.900 --> 00:30:35.380 He underwent three bone marrow transplants from 00:30:35.380 --> 00:30:37.960 his sister before his body gave out. His life 00:30:37.960 --> 00:30:40.799 was this unique and powerful bridge between highly 00:30:40.799 --> 00:30:44.700 specialized research planetary science, astrobiology, 00:30:44.859 --> 00:30:47.200 and the public. And it was all driven by this 00:30:47.200 --> 00:30:49.980 profound conviction that asking fundamental questions 00:30:49.980 --> 00:30:53.839 is the highest human calling. His legacy is secured 00:30:53.839 --> 00:30:56.200 not just in the science he confirmed, but in 00:30:56.200 --> 00:30:58.059 the millions of people he inspired to just ask 00:30:58.059 --> 00:31:00.740 why. He was the intellectual force who made the 00:31:00.740 --> 00:31:03.200 cosmos feel like home, urging us all to look 00:31:03.200 --> 00:31:05.380 up with humility, but also to look at ourselves 00:31:05.380 --> 00:31:07.880 with rigorous skepticism. And of course, we can't 00:31:07.880 --> 00:31:09.839 close this deep dive without the amusing anecdote 00:31:09.839 --> 00:31:12.299 that perfectly captures the clash between his 00:31:12.299 --> 00:31:15.140 celebrity and his demand for respect. The Apple 00:31:15.140 --> 00:31:18.759 incident. A classic. In 1994, engineers at Apple 00:31:18.759 --> 00:31:21.279 Computer codenamed their new power Macintosh 00:31:21.279 --> 00:31:24.740 7100 computer Carl Sagan. And they were openly 00:31:24.740 --> 00:31:26.539 joking that the machine would earn the company 00:31:26.539 --> 00:31:29.920 billions and billions. And Sagan, ever the stickler 00:31:29.920 --> 00:31:31.980 for ethical boundaries and concerned about an 00:31:31.980 --> 00:31:34.460 unauthorized endorsement, sent Apple a cease 00:31:34.460 --> 00:31:36.900 and desist letter. And the engineers, in a fit 00:31:36.900 --> 00:31:39.160 of, you know, classic tech rivalry pettiness, 00:31:39.339 --> 00:31:41.619 internally retaliated by temporarily changing 00:31:41.619 --> 00:31:45.099 the code name to BHA. Which stood for but had 00:31:45.099 --> 00:31:47.500 astronomer. It was a tense moment, but eventually 00:31:47.500 --> 00:31:50.420 an out -of -court settlement was reached. Apple 00:31:50.420 --> 00:31:53.380 issued a very conciliatory public statement expressing 00:31:53.380 --> 00:31:56.279 their great respect for Dr. Sagan. So despite 00:31:56.279 --> 00:31:59.000 the friction, his name literally crossed over 00:31:59.000 --> 00:32:01.900 from the stars to our desktop computers. And 00:32:01.900 --> 00:32:04.339 his name endures far more formally in space itself. 00:32:04.980 --> 00:32:07.859 The landing site of the Mars Pathfinder was renamed 00:32:07.859 --> 00:32:11.839 the Carl Sagan Memorial Station in 1997. and 00:32:11.839 --> 00:32:15.380 a main -belt asteroid is named 2709 Sagan. And 00:32:15.380 --> 00:32:17.559 in the most moving reflection after his death, 00:32:17.779 --> 00:32:20.900 his wife, Ann Druin, just perfectly encapsulated 00:32:20.900 --> 00:32:23.220 their life together and his deep, naturalistic 00:32:23.220 --> 00:32:25.740 beliefs. She noted that knowing there was no 00:32:25.740 --> 00:32:28.000 afterlife, no guaranteed reunion, made their 00:32:28.000 --> 00:32:29.960 time together all the more precious. She said, 00:32:30.079 --> 00:32:32.539 I don't think I'll ever see Carl again, but I 00:32:32.539 --> 00:32:35.099 saw him, we saw each other, we found each other 00:32:35.099 --> 00:32:37.740 in the cosmos, and that was wonderful. That appreciation 00:32:37.740 --> 00:32:40.519 of the preciousness of connection, defined by 00:32:40.519 --> 00:32:43.180 reason and wonder, is a profound summation of 00:32:43.180 --> 00:32:46.000 his life's philosophy. He didn't just teach us 00:32:46.000 --> 00:32:48.180 about the stars. He taught us how to live here 00:32:48.180 --> 00:32:51.059 on Earth. So, as you reflect on Sagan's life, 00:32:51.240 --> 00:32:53.440 the curiosity of the five -year -old in the library, 00:32:53.720 --> 00:32:56.279 the professor who rejected secrecy, the advocate 00:32:56.279 --> 00:32:58.900 who demanded intellectual honesty, will leave 00:32:58.900 --> 00:33:01.359 you with this final, provocative thought. When 00:33:01.359 --> 00:33:03.660 you're confronted with complex claims and competing 00:33:03.660 --> 00:33:06.140 narratives in your own world, what specific, 00:33:06.240 --> 00:33:08.539 extraordinary claims are you applying the Sagan 00:33:08.539 --> 00:33:11.220 standard to? And what evidence by that high bar 00:33:11.220 --> 00:33:12.220 are you demanding?