WEBVTT 00:00:00.000 --> 00:00:04.259 In August 1977, a radio telescope caught this, 00:00:04.259 --> 00:00:08.880 uh, just roaring, deafening signal from deep 00:00:08.880 --> 00:00:11.859 space. Yeah. And it lasted exactly 72 seconds. 00:00:12.000 --> 00:00:14.460 Right. Exactly 72 seconds. And it looked completely 00:00:14.460 --> 00:00:16.800 identical to the mathematical prediction of an 00:00:16.800 --> 00:00:19.219 intentional alien broadcast down to the, you 00:00:19.219 --> 00:00:20.960 know, the precise frequency. But then it just 00:00:20.960 --> 00:00:24.280 vanished. Vanished. Yeah. For decades. Nothing 00:00:24.280 --> 00:00:26.870 but absolute silence. So welcome to the Deep 00:00:26.870 --> 00:00:30.070 Dive. Our mission today is taking a single comprehensive 00:00:30.070 --> 00:00:34.070 Wikipedia article and extracting the absolute 00:00:34.070 --> 00:00:36.329 most mind -bending details about one of the greatest 00:00:36.329 --> 00:00:38.929 modern mysteries of space exploration. The wow 00:00:38.929 --> 00:00:40.929 signal. The wow signal. And for you listening 00:00:40.929 --> 00:00:42.450 right now, if you love cutting through the noise 00:00:42.450 --> 00:00:44.329 to get straight to the mechanics of an anomaly 00:00:44.329 --> 00:00:47.070 that just defies all standard explanations, well, 00:00:47.149 --> 00:00:49.250 this is your masterclass. It really is. And looking 00:00:49.250 --> 00:00:51.070 at your backdrop right now, the visual perfectly 00:00:51.070 --> 00:00:54.049 sets the tone here. We have these retro 1970s 00:00:54.049 --> 00:00:56.189 computer punch cards, and they're seamlessly 00:00:56.189 --> 00:00:59.130 fading into these really expansive modern star 00:00:59.130 --> 00:01:02.460 charts. Yeah, I love it because we are standing 00:01:02.460 --> 00:01:05.640 right at the interception of somewhat primitive, 00:01:05.879 --> 00:01:09.920 clunky 1970s computing and incredibly vast cosmic 00:01:09.920 --> 00:01:13.120 mysteries. I mean, it is the ultimate cold case 00:01:13.120 --> 00:01:16.280 of astronomy. It's a single data point, so physically 00:01:16.280 --> 00:01:19.920 perfect, yet so frustratingly solitary that it 00:01:19.920 --> 00:01:22.640 has kept astrobiologists just agonizing over 00:01:22.640 --> 00:01:24.980 the data for nearly half a century. So let's 00:01:24.980 --> 00:01:28.200 establish the scene. It's August 1977. We are 00:01:28.200 --> 00:01:30.069 at Ohio State University. University's radio 00:01:30.069 --> 00:01:32.609 telescope, which was affectionately nicknamed 00:01:32.609 --> 00:01:35.730 Big Ear. And a volunteer astronomer named Jerry 00:01:35.730 --> 00:01:38.840 Ammon is reviewing the data. And back then, you 00:01:38.840 --> 00:01:41.040 know, reviewing data wasn't looking at a sleek 00:01:41.040 --> 00:01:43.659 monitor. Oh no, not at all. It meant physically 00:01:43.659 --> 00:01:46.239 perusing massive stacks of continuous form -line 00:01:46.239 --> 00:01:48.879 printer paper that was just spat out by an IBM 00:01:48.879 --> 00:01:51.959 1130 mainframe computer. Right, just reams of 00:01:51.959 --> 00:01:54.200 it. So he's looking down at these endless columns 00:01:54.200 --> 00:01:56.840 of alphanumeric characters, and he sees a string 00:01:56.840 --> 00:01:59.640 of text so shocking that he grabs a red pen, 00:02:00.040 --> 00:02:02.700 circles it, and actually writes the word, wow, 00:02:02.760 --> 00:02:05.040 in the margin. The literal margin notes of history. 00:02:05.280 --> 00:02:07.840 Exactly. Okay, let's unpack this. The text he 00:02:07.840 --> 00:02:12.639 circled notoriously reads as 6EQUJ5. And we really 00:02:12.639 --> 00:02:14.800 need to clear up the biggest public misconception 00:02:14.800 --> 00:02:17.340 right away here. Yes, please. Because this isn't 00:02:17.340 --> 00:02:19.439 to cipher, right? It's not a secret alien alphabet 00:02:19.439 --> 00:02:22.860 we need to translate. It's just a volume knob. 00:02:23.159 --> 00:02:25.360 That's a perfect way to put it. Right. Like the 00:02:25.360 --> 00:02:27.800 system measures signal to noise ratio, and when 00:02:27.800 --> 00:02:30.219 the volume gets dangerously, ear -shatteringly 00:02:30.219 --> 00:02:33.060 loud, it literally runs out of numbers one through 00:02:33.060 --> 00:02:35.539 nine and just switches over the letters. Yeah. 00:02:35.710 --> 00:02:38.030 The measuring system adopted for this specific 00:02:38.030 --> 00:02:41.009 experiment was incredibly rigid. Like, a blank 00:02:41.009 --> 00:02:43.509 space on that line printer paper just meant the 00:02:43.509 --> 00:02:46.150 intensity was normal, ambient background noise. 00:02:46.169 --> 00:02:47.909 It's just the static of the universe. Exactly. 00:02:48.069 --> 00:02:50.469 Between zero and one standard deviation above 00:02:50.469 --> 00:02:52.430 the baseline. The numbers one through nine meant 00:02:52.430 --> 00:02:54.689 it was one to nine standard deviations above 00:02:54.689 --> 00:02:57.469 that noise. OK. But if a signal went above nine, 00:02:57.610 --> 00:03:00.650 the computer switched to the alphabet. So A meant 00:03:00.650 --> 00:03:04.550 an intensity of 10 to 11, B meant 11 to 12, and 00:03:04.550 --> 00:03:07.080 so on. Which means tracing that alphabet all 00:03:07.080 --> 00:03:09.340 the way up to you puts us at an intensity of 00:03:09.340 --> 00:03:11.759 30 standard deviations above the background noise. 00:03:12.819 --> 00:03:15.300 I mean, that is a massive spike in radio energy. 00:03:15.379 --> 00:03:18.400 It is a deafening roar. And the mechanical rhythm 00:03:18.400 --> 00:03:21.939 of how this was recorded is, well, it's vital 00:03:21.939 --> 00:03:25.210 to understanding why it's so compelling. So, 00:03:25.550 --> 00:03:28.129 the Big Ear Telescope sampled the incoming radio 00:03:28.129 --> 00:03:32.069 signal for exactly 10 seconds. Then, the IBM 00:03:32.069 --> 00:03:35.030 computer took exactly two seconds to process 00:03:35.030 --> 00:03:37.990 that sample and physically strike a single character 00:03:37.990 --> 00:03:40.469 onto the printout. Okay, so every character is 00:03:40.469 --> 00:03:42.610 a 12 -second window. Right. So when you read 00:03:42.610 --> 00:03:47.370 down that specific column 6 EQ UJ5, you're looking 00:03:47.370 --> 00:03:50.189 at a 12 -second pulse beat by mechanical beat. 00:03:50.270 --> 00:03:52.960 Wow. It captures a signal that rises dramatically 00:03:52.960 --> 00:03:56.120 out of the background static, hits this unbelievable 00:03:56.120 --> 00:03:59.219 peak of intensity at you, and then steadily fades 00:03:59.219 --> 00:04:01.620 back down into the noise. Here's where it gets 00:04:01.620 --> 00:04:04.139 really interesting. Because, you know, knowing 00:04:04.139 --> 00:04:05.939 the mechanics of the code is one thing, but a 00:04:05.939 --> 00:04:08.139 loud noise shouldn't immediately make a rational 00:04:08.139 --> 00:04:10.020 astronomer think of aliens. No, it shouldn't. 00:04:10.099 --> 00:04:12.020 The physical anatomy of the signal is what makes 00:04:12.020 --> 00:04:14.840 it so legendary, specifically the duration. It 00:04:14.840 --> 00:04:18.199 lasted for exactly 72 seconds. Now, I'm stuck 00:04:18.199 --> 00:04:21.980 on this 72 second window. Because, like, if I'm 00:04:21.980 --> 00:04:24.060 an advanced civilization trying to contact another 00:04:24.060 --> 00:04:26.899 world, I'm leaving my transmitter on all year. 00:04:26.939 --> 00:04:29.579 You think so, yeah. I'm broadcasting continuously. 00:04:29.759 --> 00:04:32.699 Why, 72 seconds, couldn't it just be a random 00:04:32.699 --> 00:04:35.220 Earth radio broadcast sweeping past the telescope? 00:04:36.040 --> 00:04:38.579 Or like a passing military plane? See, that is 00:04:38.579 --> 00:04:41.360 the logical first assumption. But the 72 second 00:04:41.360 --> 00:04:44.430 duration is actually the absolute strongest piece 00:04:44.430 --> 00:04:46.589 of evidence against it being an Earth -based 00:04:46.589 --> 00:04:49.189 broadcast. Wait, really? How? We have to look 00:04:49.189 --> 00:04:51.209 at the physical engineering of the Big Ear Telescope. 00:04:51.769 --> 00:04:54.069 Unlike modern radio telescopes, you know, the 00:04:54.069 --> 00:04:56.709 massive dishes you see tilting and pivoting to 00:04:56.709 --> 00:05:00.050 track an object across the sky, Big Ear was essentially 00:05:00.050 --> 00:05:02.310 fixed to the ground. Oh, right. It was a transit 00:05:02.310 --> 00:05:05.089 instrument. Exactly. It could tilt slightly up 00:05:05.089 --> 00:05:07.430 and down to adjust its altitude, but to scan 00:05:07.430 --> 00:05:10.189 across the sky from east to west, it literally 00:05:10.189 --> 00:05:12.300 relied on the rotation of the Earth. So it was 00:05:12.300 --> 00:05:14.379 just staring at a thick strip of the sky, letting 00:05:14.379 --> 00:05:17.519 the earth spin, do the panning. You got it. And 00:05:17.519 --> 00:05:19.720 because of the specific width of the telescope's 00:05:19.720 --> 00:05:22.740 observation window, combined with the exact rotational 00:05:22.740 --> 00:05:25.839 speed of the Earth, a fixed celestial object 00:05:25.839 --> 00:05:28.920 in deep space would stay in Big Ear's view for 00:05:28.920 --> 00:05:34.660 exactly 72 seconds. Wow. Not 71, not 73. If a 00:05:34.660 --> 00:05:36.899 continuous stationary signal was beaming toward 00:05:36.899 --> 00:05:39.660 Earth from a distant star system, the telescope 00:05:39.660 --> 00:05:42.420 would pick it up as a gradual increase in volume 00:05:42.420 --> 00:05:45.579 for the first 36 seconds as the telescope's beam 00:05:45.360 --> 00:05:48.000 rotated into the signal. It would peak right 00:05:48.000 --> 00:05:50.220 in the middle and then display a gradual decrease 00:05:50.220 --> 00:05:53.060 for the final 36 seconds as the telescope rotated 00:05:53.060 --> 00:05:56.459 away. So 36 seconds up, peak at the U, and 36 00:05:56.459 --> 00:05:59.160 seconds down. It perfectly maps to a stationary 00:05:59.160 --> 00:06:01.480 point source in deep space. It is flawless. I 00:06:01.480 --> 00:06:03.899 mean, a passing airplane or a satellite in orbit 00:06:03.899 --> 00:06:05.920 moves independently of the Earth's rotation. 00:06:06.339 --> 00:06:08.319 They would streak across the observation window 00:06:08.319 --> 00:06:11.259 much faster, or they'd linger longer, which would 00:06:11.259 --> 00:06:13.939 totally destroy that perfect 72 -second bell 00:06:13.939 --> 00:06:16.480 curve. That makes total sense. And the frequency 00:06:16.480 --> 00:06:18.300 of the signal is just as important as the shape 00:06:18.300 --> 00:06:21.620 of it. The signal came in at exactly 1 ,420 megahertz. 00:06:21.779 --> 00:06:25.120 Yes, the hydrogen line. Exactly. Now back in 00:06:25.120 --> 00:06:28.639 1959, physicists Philip Morrison and Giuseppe 00:06:28.639 --> 00:06:32.040 Cocconi wrote a seminal paper predicting that 00:06:32.040 --> 00:06:34.939 if an advanced alien civilization wanted to communicate 00:06:34.939 --> 00:06:38.000 across the galaxy, they would inherently use 00:06:38.000 --> 00:06:40.699 this exact frequency. And the physics behind 00:06:40.699 --> 00:06:42.959 that choice are fascinating. It's not arbitrary 00:06:42.959 --> 00:06:46.779 at all. 1420 megahertz is the natural emission 00:06:46.779 --> 00:06:49.199 frequency of neutral hydrogen, right? Yes, which 00:06:49.199 --> 00:06:52.000 is the most abundant element in the entire universe. 00:06:52.199 --> 00:06:54.300 Right. So if you look at a neutral hydrogen atom, 00:06:55.160 --> 00:06:57.920 you have a proton and an electron. Both possess 00:06:57.920 --> 00:07:00.519 a quantum property called spin. Correct. And 00:07:00.519 --> 00:07:02.660 occasionally the electron flips its spin direction. 00:07:02.939 --> 00:07:05.379 When that spin flip transition happens, the atom 00:07:05.379 --> 00:07:07.420 releases a tiny amount of energy in the form 00:07:07.420 --> 00:07:10.040 of a radio photon with a wavelength of exactly 00:07:10.040 --> 00:07:13.819 21 centimeters. Which equals a frequency of 1420 00:07:13.819 --> 00:07:16.540 megahertz. Exactly. Any technologically advanced 00:07:16.540 --> 00:07:18.899 civilization anywhere in the universe would know 00:07:18.899 --> 00:07:21.120 this fundamental rule of physics. They absolutely 00:07:21.120 --> 00:07:23.199 would. It is a universal constant. So it kind 00:07:23.199 --> 00:07:25.000 of operates like the universal maritime distress 00:07:25.000 --> 00:07:28.230 channel. Oh, that's a good analogy. Like, if 00:07:28.230 --> 00:07:30.209 you are a ship out on the ocean and you want 00:07:30.209 --> 00:07:32.870 to hail another vessel, you don't just pick a 00:07:32.870 --> 00:07:34.829 random radio frequency and hope someone is listening. 00:07:34.870 --> 00:07:37.370 No, of course not. You broadcast on the dedicated 00:07:37.370 --> 00:07:40.370 channel that you know every other sailor is already 00:07:40.370 --> 00:07:42.819 actively monitoring. Right. And what's fascinating 00:07:42.819 --> 00:07:47.459 here is that on Earth, that specific 1420 megahertz 00:07:47.459 --> 00:07:51.079 frequency is actually a globally protected spectrum. 00:07:51.199 --> 00:07:54.019 Really? Protected how? By international agreement, 00:07:54.139 --> 00:07:56.860 it is reserved exclusively for passive astronomical 00:07:56.860 --> 00:08:00.600 research. Terrestrial transmissions, so military 00:08:00.600 --> 00:08:03.079 radar, commercial radio, television broadcasts, 00:08:03.079 --> 00:08:06.519 they are strictly forbidden by law from broadcasting 00:08:06.519 --> 00:08:09.160 anywhere near that frequency to prevent interference. 00:08:09.279 --> 00:08:13.560 Wow. that precisely mimics a deep space origin, 00:08:14.040 --> 00:08:16.199 lasts exactly the length of time a deep space 00:08:16.199 --> 00:08:19.259 object should, and comes in on the one universally 00:08:19.259 --> 00:08:21.779 protected frequency that physicists predicted 00:08:21.779 --> 00:08:24.839 an alien civilization would use. Everything about 00:08:24.839 --> 00:08:27.660 its physical profile just screamed extraterrestrial. 00:08:27.980 --> 00:08:30.120 But, I mean, if we have the perfect signature 00:08:30.120 --> 00:08:32.320 and the perfect frequency, why didn't we just 00:08:32.320 --> 00:08:34.379 point every dish on Earth at that spot in the 00:08:34.379 --> 00:08:36.460 sky and start talking back? Well, that's the 00:08:36.460 --> 00:08:39.100 tragedy of it. Yeah, this leads us directly into 00:08:39.100 --> 00:08:42.039 the geographical ambiguity of the signal, which 00:08:42.039 --> 00:08:44.799 has to be the most agonizing data limitation 00:08:44.799 --> 00:08:47.379 in modern astronomy. We literally didn't know 00:08:47.379 --> 00:08:50.399 exactly where to point. We didn't. And it comes 00:08:50.399 --> 00:08:52.919 down to a quirky design limitation of the Big 00:08:52.919 --> 00:08:55.519 Ear Telescope's data processing. How'd it work? 00:08:55.820 --> 00:08:59.059 Big Ear utilized two feed horns. Think of them 00:08:59.059 --> 00:09:02.200 as two separate antennas sitting side by side, 00:09:02.419 --> 00:09:04.059 pointing in slightly different directions in 00:09:04.059 --> 00:09:07.320 the sky following the Earth's rotation. OK. To 00:09:07.320 --> 00:09:10.129 filter out background static, The receiver system 00:09:10.129 --> 00:09:12.850 was designed to electronically subtract the signal 00:09:12.850 --> 00:09:15.570 of one horn from the other. Right. That makes 00:09:15.570 --> 00:09:17.950 sense for cleaning up the data. Yeah, but the 00:09:17.950 --> 00:09:20.409 problem is the wow signal hit one of the feed 00:09:20.409 --> 00:09:22.769 horns, but not the other. And because the computer 00:09:22.769 --> 00:09:24.750 only recorded the difference between the two 00:09:24.750 --> 00:09:27.370 horns to save processing power, it was physically 00:09:27.370 --> 00:09:29.490 impossible to determine which of the two horns 00:09:29.490 --> 00:09:32.429 actually received the incoming signal. Oh, no. 00:09:32.769 --> 00:09:35.490 So we had the declination, the up and down coordinate 00:09:35.490 --> 00:09:38.379 locked in perfectly. Yes. But For the right ascension, 00:09:38.639 --> 00:09:40.580 the side -to -side coordinate, we were left with 00:09:40.580 --> 00:09:44.039 two entirely separate, non -overlapping regions 00:09:44.039 --> 00:09:46.960 in the constellation Sagittarius. Exactly. It's 00:09:46.960 --> 00:09:48.700 like knowing a screen came from the fifth floor 00:09:48.700 --> 00:09:50.980 of an apartment building. But because of the 00:09:50.980 --> 00:09:52.419 echo, you don't know if it came from the apartment 00:09:52.419 --> 00:09:54.559 on the far left or the apartment on the far right. 00:09:54.740 --> 00:09:57.200 And you were just staring at two doors, completely 00:09:57.200 --> 00:10:00.659 paralyzed. But astronomers didn't just give up. 00:10:01.659 --> 00:10:03.500 Let's fast forward to the modern day. because 00:10:03.500 --> 00:10:05.879 our mapping of the cosmos has improved exponentially 00:10:05.879 --> 00:10:09.379 since 1977. Oh, definitely. In 2022, an incredible 00:10:09.379 --> 00:10:11.559 paper was published in the International Journal 00:10:11.559 --> 00:10:15.039 of Astrobiology. Researchers utilized the Gaia 00:10:15.039 --> 00:10:18.159 satellite database, which provides spectacularly 00:10:18.159 --> 00:10:21.159 precise 3D maps of our galaxy to look at what 00:10:21.159 --> 00:10:23.539 is actually sitting inside those two specific 00:10:23.539 --> 00:10:25.360 antenna -pointed coordinates. And they found 00:10:25.360 --> 00:10:27.899 something, right? They identified three likely 00:10:27.899 --> 00:10:30.659 Sun -like stars. And one of them is a prime candidate. 00:10:30.860 --> 00:10:37.600 A star designated 2MASS192819822640123. Quite 00:10:37.600 --> 00:10:40.580 a catchy name. Right. But it's perfectly situated 00:10:40.580 --> 00:10:43.600 about 1800 light years away. And it possesses 00:10:43.600 --> 00:10:46.399 a temperature, a radius, and a luminosity incredibly 00:10:46.399 --> 00:10:49.720 similar to our own sun. It aligns brilliantly 00:10:49.720 --> 00:10:52.559 with theoretical estimations of where an intelligent 00:10:52.559 --> 00:10:55.320 civilization might evolve. So we finally had 00:10:55.320 --> 00:10:58.720 prime targets. But the silence has been deafening. 00:10:58.960 --> 00:11:01.120 Yeah. I mean, the follow -up efforts to find 00:11:01.120 --> 00:11:03.860 this signal again have been massive. They span 00:11:03.860 --> 00:11:06.820 decades and utilize increasingly powerful technology. 00:11:07.000 --> 00:11:08.940 Absolutely. Like Robert Gray searched for it 00:11:08.940 --> 00:11:11.500 in the late 1980s with the Meta array at Harvard. 00:11:12.120 --> 00:11:15.200 He tried again in the mid 1990s with the incredibly 00:11:15.200 --> 00:11:17.960 sensitive, very large array in New Mexico. And 00:11:17.960 --> 00:11:20.590 they didn't stop there. Right. As a direct response 00:11:20.590 --> 00:11:23.070 to that 2022 discovery of the Sun -like stars, 00:11:23.470 --> 00:11:25.190 the Breakthrough Listen project pointed both 00:11:25.190 --> 00:11:27.610 the massive Green Bank Telescope and the Allen 00:11:27.610 --> 00:11:30.289 Telescope Array right at those specific stars 00:11:30.289 --> 00:11:32.610 for a highly coordinated search. They scanned 00:11:32.610 --> 00:11:34.710 for hours. And they found absolutely nothing. 00:11:35.009 --> 00:11:37.169 Nothing at all. This raises an important question 00:11:37.169 --> 00:11:39.970 about how we validate anomalous data. Douglas 00:11:39.970 --> 00:11:42.909 Vakosh, the president of METI Messaging Extraterrestrial 00:11:42.909 --> 00:11:45.190 Intelligence, makes a crucial point about this. 00:11:45.350 --> 00:11:48.039 What does he say? In the realm of science, a 00:11:48.039 --> 00:11:50.639 discovery isn't truly a discovery unless it can 00:11:50.639 --> 00:11:53.620 be replicated. Without replication, without being 00:11:53.620 --> 00:11:56.100 able to point a telescope at a coordinate and 00:11:56.100 --> 00:11:58.879 measure the phenomenon a second time, the wow 00:11:58.879 --> 00:12:01.259 signal has very little scientific credibility 00:12:01.259 --> 00:12:05.000 as a confirmed alien broadcast. So a one -off 00:12:05.000 --> 00:12:07.559 event, no matter how flawlessly it aligns with 00:12:07.559 --> 00:12:11.340 our mathematical predictions, is just an agonizing 00:12:11.340 --> 00:12:13.720 anomaly. Exactly. So what does this all mean? 00:12:14.159 --> 00:12:16.690 Since science demands replication, Researchers 00:12:16.690 --> 00:12:19.429 have spent decades fiercely trying to prove it 00:12:19.429 --> 00:12:22.210 was just a natural astronomical glitch or some 00:12:22.210 --> 00:12:25.429 terrestrial error. Oh, yeah. The debunking attempts 00:12:25.429 --> 00:12:27.610 are fascinating in their own right. Let's talk 00:12:27.610 --> 00:12:29.730 about those. Well, one of the most famous recent 00:12:29.730 --> 00:12:32.730 attempts came in 2017 from Antonio Paris, an 00:12:32.730 --> 00:12:35.029 astronomy professor. He proposed that the signal 00:12:35.029 --> 00:12:38.009 was caused by a massive naturally occurring hydrogen 00:12:38.009 --> 00:12:40.710 cloud surrounding two comets. Comets Christensen 00:12:40.710 --> 00:12:43.009 and Gibbs, I believe. Right, which were supposedly 00:12:43.009 --> 00:12:45.649 moving through that region of space in 1977. 00:12:45.929 --> 00:12:48.289 But the original Big Ear team dismantled that 00:12:48.289 --> 00:12:50.750 theory in the literature with just ruthless efficiency. 00:12:50.870 --> 00:12:53.350 They really did. They pointed out catastrophic 00:12:53.350 --> 00:12:57.049 flaws in the math. First, those specific comets 00:12:57.049 --> 00:12:59.649 weren't actually in the telescope's beam at the 00:12:59.649 --> 00:13:02.649 correct time. Kind of a big problem. Yeah. Second, 00:13:03.110 --> 00:13:05.450 the physics of cometary emission don't work. 00:13:06.110 --> 00:13:08.789 Comets simply do not emit hydrogen signals anywhere 00:13:08.789 --> 00:13:11.350 near the massive strength required to produce 00:13:11.350 --> 00:13:14.529 a U on that printout. Right. And third, Paris's 00:13:14.529 --> 00:13:16.830 theory couldn't explain the feed horn problem. 00:13:17.250 --> 00:13:19.879 Comets move slowly across the sky. So if it was 00:13:19.879 --> 00:13:21.720 a comet, the signal would have been picked up 00:13:21.720 --> 00:13:23.820 by the first feed horn, and then a few minutes 00:13:23.820 --> 00:13:25.460 later, it would have been picked up by the second 00:13:25.460 --> 00:13:27.779 feed horn. But the wow signal only triggered 00:13:27.779 --> 00:13:30.960 one. Exactly. Even Jerry Immen himself, the man 00:13:30.960 --> 00:13:33.980 who wrote wow on the paper, he heavily doubted 00:13:33.980 --> 00:13:36.639 the extraterrestrial hypothesis for a time. What 00:13:36.639 --> 00:13:39.179 did he think it was? He proposed a terrestrial 00:13:39.179 --> 00:13:41.240 explanation, suggesting it might have been a 00:13:41.240 --> 00:13:43.659 secret military Earth signal that accidentally 00:13:43.659 --> 00:13:46.120 bounced off a piece of space debris and reflected 00:13:46.120 --> 00:13:48.279 perfectly back into the telescope. Oh, like space 00:13:48.279 --> 00:13:51.799 jumps. Yeah, but even later retracted that skepticism. 00:13:52.179 --> 00:13:53.899 Further physics modeling proved that a piece 00:13:53.899 --> 00:13:56.220 of metallic space debris tumbling in low Earth 00:13:56.220 --> 00:13:59.080 orbit simply cannot reflect a terrestrial signal 00:13:59.080 --> 00:14:01.820 back into a fixed telescope to perfectly mimic 00:14:01.820 --> 00:14:05.240 a deep space source with a flawless 72 second 00:14:05.240 --> 00:14:07.539 rise and fall. Right, because space junk moves 00:14:07.539 --> 00:14:09.539 far too fast and erratically. Exactly, it just 00:14:09.539 --> 00:14:12.320 doesn't work. But just recently, the debate was 00:14:12.320 --> 00:14:16.679 blown wide open again. In August 2024, the Planetary 00:14:16.679 --> 00:14:19.539 Habitability Laboratory published a fascinating 00:14:19.539 --> 00:14:23.000 preprint drawing on data from the Arecibo Observatory. 00:14:23.019 --> 00:14:26.259 Yes. And they actually proposed a totally new 00:14:26.259 --> 00:14:28.700 natural hypothesis that relies on some incredibly 00:14:28.700 --> 00:14:31.340 complex astrophysics. This is currently one of 00:14:31.340 --> 00:14:33.919 the most compelling natural explanations we have. 00:14:34.110 --> 00:14:36.649 Break it down for us. So the researchers proposed 00:14:36.649 --> 00:14:39.169 that the Wow signal was the result of a very 00:14:39.169 --> 00:14:42.590 rare transient astrophysical event known as stimulated 00:14:42.590 --> 00:14:46.110 emission, essentially a cosmic maser. OK. The 00:14:46.110 --> 00:14:48.350 theory suggests there was a cold, dark cloud 00:14:48.350 --> 00:14:51.129 of hydrogen gas sitting out in space. Suddenly, 00:14:51.149 --> 00:14:53.509 it was struck by massive stellar emissions from 00:14:53.509 --> 00:14:56.169 a highly energetic cosmic event behind it. Like 00:14:56.169 --> 00:14:58.850 what? Perhaps a flare from a magnetar, which 00:14:58.850 --> 00:15:01.970 is a ridiculously dense neutron star with a magnetic 00:15:01.970 --> 00:15:04.580 field quadrillions of time stronger than Earth's. 00:15:04.580 --> 00:15:07.299 That sounds intense. It is. This sudden immense 00:15:07.299 --> 00:15:10.059 injection of energy into the cold hydrogen cloud 00:15:10.059 --> 00:15:12.539 caused the atoms to synchronize their electron 00:15:12.539 --> 00:15:14.779 spin flips. So it triggered a chain reaction. 00:15:14.940 --> 00:15:17.700 Exactly. The energized cloud experienced a sudden, 00:15:17.879 --> 00:15:20.860 dramatic, highly focused surge in brightness 00:15:20.860 --> 00:15:26.299 at that exact 1420 megahertz frequency. It amplified 00:15:26.299 --> 00:15:28.659 the background radiation exponentially for a 00:15:28.659 --> 00:15:31.580 very brief period. So mechanically it's like 00:15:31.580 --> 00:15:33.960 a cosmic neon sign. floating invisibly in the 00:15:33.960 --> 00:15:36.059 dark. That's a great analogy. Right. It has all 00:15:36.059 --> 00:15:39.600 the gas inside, but no electricity. Then a magnetar 00:15:39.600 --> 00:15:42.019 flare plugs it into a massive momentary power 00:15:42.019 --> 00:15:44.960 surge. The hydrogen gas burns blindingly bright, 00:15:45.179 --> 00:15:47.080 beaming a highly focused laser of radio waves 00:15:47.080 --> 00:15:48.919 right as our telescope happens to be sweeping 00:15:48.919 --> 00:15:51.799 past that exact patch of sky. Yep. And then the 00:15:51.799 --> 00:15:53.940 energy dissipates, the cloud shorts out, and 00:15:53.940 --> 00:15:56.299 it goes dark forever. That perfectly captures 00:15:56.299 --> 00:15:59.049 the mechanics of a cosmic maser. It accounts 00:15:59.049 --> 00:16:01.190 for why the signal was so incredibly strong, 00:16:01.610 --> 00:16:04.210 why it was locked precisely at the hydrogen frequency, 00:16:04.490 --> 00:16:06.750 and most importantly, why we have never seen 00:16:06.750 --> 00:16:09.149 it again despite decades of searching. Because 00:16:09.149 --> 00:16:12.529 it was a one -time event. Right. It wasn't an 00:16:12.529 --> 00:16:14.950 alien beacon left on. It was an astrophysical 00:16:14.950 --> 00:16:17.610 flash bulb going off in the dark. But regardless 00:16:17.610 --> 00:16:19.970 of whether it was a glowing cloud of synchronized 00:16:19.970 --> 00:16:23.299 hydrogen gas, or an actual alien civilization. 00:16:23.720 --> 00:16:25.919 I mean, the psychological impact of the Wow signal 00:16:25.919 --> 00:16:28.519 remains profound. Oh, absolutely. It totally 00:16:28.519 --> 00:16:30.960 changed our relationship with the cosmos. We 00:16:30.960 --> 00:16:33.360 desperately wanted to reach back into the dark. 00:16:34.200 --> 00:16:36.980 In 2012, for the 35th anniversary of the signal, 00:16:37.539 --> 00:16:39.840 the Arecibo Observatory decided to officially 00:16:39.840 --> 00:16:42.720 talk back. Yes, they did. They gathered 10 ,000 00:16:42.720 --> 00:16:45.159 promotional tweets using the hashtag chasing 00:16:45.159 --> 00:16:47.879 UFOs, which ironically was for a television show. 00:16:48.220 --> 00:16:50.440 And they beamed this digital stream of Twitter 00:16:50.440 --> 00:16:53.139 messages directly at nearby stars. The intention 00:16:53.139 --> 00:16:56.039 to respond was a milestone in human history, 00:16:56.240 --> 00:16:59.019 even if the execution was deeply, deeply flawed. 00:16:59.220 --> 00:17:01.580 Deeply flawed is an understatement. Yeah, the 00:17:01.580 --> 00:17:04.099 historical record of that event contains an incredible 00:17:04.099 --> 00:17:06.920 irony. According to the former director of the 00:17:06.920 --> 00:17:09.940 Arecibo Observatory, The sheer power required 00:17:09.940 --> 00:17:13.099 to transmit that complex digital data caused 00:17:13.099 --> 00:17:15.779 the transmitter to literally overheat shortly 00:17:15.779 --> 00:17:18.259 into the very first transmission. Wait, they 00:17:18.259 --> 00:17:20.400 blew out their own equipment trying to send tweets 00:17:20.400 --> 00:17:23.319 to aliens? They did, and the data gets even worse. 00:17:23.440 --> 00:17:25.819 How could it be worse? Because of the equipment 00:17:25.819 --> 00:17:28.250 failure, The message was only sent in the direction 00:17:28.250 --> 00:17:31.390 of one of their pre -selected star targets. And 00:17:31.390 --> 00:17:33.690 none of the targets they chose were even in the 00:17:33.690 --> 00:17:35.970 possible region of Sagittarius where the wow 00:17:35.970 --> 00:17:38.910 signal actually originated. So to summarize our 00:17:38.910 --> 00:17:41.890 grand cosmic greeting, we took 10 ,000 tweets, 00:17:42.529 --> 00:17:44.690 pointed our massive radio dish at the entirely 00:17:44.690 --> 00:17:47.250 wrong part of the sky, yelled into the void, 00:17:47.569 --> 00:17:49.549 and promptly melted our own transmitter. Pretty 00:17:49.549 --> 00:17:52.410 much, yeah. But despite our bumbling, the signal's 00:17:52.410 --> 00:17:55.690 legacy endures. It showed up in the 1994 season 00:17:55.690 --> 00:17:58.589 premiere of The X -Files. It was a foundational 00:17:58.589 --> 00:18:01.450 plot point in the 2024 sci -fi series 3 body 00:18:01.450 --> 00:18:04.210 problem. It just has this absolute grip on our 00:18:04.210 --> 00:18:06.230 collective imagination. If we connect this to 00:18:06.230 --> 00:18:09.630 the bigger picture... The WOW signal is the ultimate 00:18:09.630 --> 00:18:12.130 tantalizing data point in the history of science. 00:18:12.190 --> 00:18:14.809 It really is. Even if we never fully solve it, 00:18:14.849 --> 00:18:18.109 it served a vital, transformative purpose. It 00:18:18.109 --> 00:18:20.910 forced humanity to drastically refine the mathematics 00:18:20.910 --> 00:18:23.329 and hardware of our radio astronomy techniques. 00:18:24.009 --> 00:18:27.069 It forced us to seriously debate our cosmic communication 00:18:27.069 --> 00:18:30.750 protocols, how we listen, and how we might responsibly 00:18:30.960 --> 00:18:34.740 respond. And as we saw with the 2024 hydrogen 00:18:34.740 --> 00:18:37.460 cloud maser theory, it is forcing us to look 00:18:37.460 --> 00:18:41.079 much closer at rare transient astrophysical phenomena 00:18:41.079 --> 00:18:43.819 that we might otherwise completely ignore. And 00:18:43.819 --> 00:18:45.960 for you listening, whether you walk away from 00:18:45.960 --> 00:18:48.240 this deep dive believing it was extraterrestrial 00:18:48.240 --> 00:18:51.019 intelligence saying hello, or a freak energized 00:18:51.019 --> 00:18:53.460 hydrogen cloud acting like a cosmic neon sign, 00:18:54.000 --> 00:18:57.140 the 72 second anomaly proves just how much of 00:18:57.140 --> 00:18:59.039 the universe's mechanics are still completely 00:18:59.039 --> 00:19:01.220 unknown to us. We really don't know much at all. 00:19:01.299 --> 00:19:03.359 We have only just opened our eyes to the radio 00:19:03.359 --> 00:19:05.880 universe. And I want to leave you with one final 00:19:05.880 --> 00:19:08.059 thought to mull over, building on what we discussed 00:19:08.059 --> 00:19:10.940 about that strict 70 second window and the rotation 00:19:10.940 --> 00:19:13.230 of the Earth. Oh, this is a good one. We spent 00:19:13.230 --> 00:19:15.670 decades analyzing the contents of the signal. 00:19:16.609 --> 00:19:18.890 But if it really was an extraterrestrial civilization 00:19:18.890 --> 00:19:21.470 out there, what if the message wasn't hidden 00:19:21.470 --> 00:19:23.809 in the radio wave itself? What if it was the 00:19:23.809 --> 00:19:26.329 delivery? Right. What if the message was in the 00:19:26.329 --> 00:19:29.150 exact timing of its arrival? What if an intelligence 00:19:29.150 --> 00:19:32.150 out there calculated the exact rotational speed 00:19:32.150 --> 00:19:36.150 of our planet, deduced exactly when our primitive 00:19:36.359 --> 00:19:39.220 fixed radio telescopes would be sweeping past 00:19:39.220 --> 00:19:42.140 that precise patch of sky and send a quick 72 00:19:42.140 --> 00:19:44.759 second flash at the exact millisecond they knew 00:19:44.759 --> 00:19:46.880 we'd be looking. It gives you chills. Just something 00:19:46.880 --> 00:19:48.480 to think about the next time you look up at the 00:19:48.480 --> 00:19:48.839 night sky.