WEBVTT 00:00:07.429 --> 00:00:10.609 Howdy Star Gazers and welcome to Star Trails. 00:00:10.789 --> 00:00:13.310 I'm Drew and I'll be your guide to the night 00:00:13.310 --> 00:00:16.589 sky for the week of October 26 through November 00:00:16.589 --> 00:00:20.050 the 1st. The calendar is turning toward November 00:00:20.050 --> 00:00:23.489 now and the stars have that unmistakable autumn 00:00:23.489 --> 00:00:26.789 clarity. The air is a little sharper, the nights 00:00:26.789 --> 00:00:30.670 come earlier, and the sky feels deeper, like 00:00:30.670 --> 00:00:33.649 it's holding its breath before winter sets in. 00:00:33.880 --> 00:00:37.659 Also, Halloween is later this week, and for our 00:00:37.659 --> 00:00:41.000 final episode of October, we're going to examine 00:00:41.000 --> 00:00:45.020 another eerie topic. In a universe as vast as 00:00:45.020 --> 00:00:48.079 ours, we ask the question, where is everybody? 00:00:48.960 --> 00:00:52.159 We're not looking for little green men or flying 00:00:52.159 --> 00:00:55.219 saucers necessarily, but with all the potential 00:00:55.219 --> 00:00:58.520 worlds that surround us, why haven't we received 00:00:58.520 --> 00:01:02.020 any indication that someone or something is out 00:01:02.020 --> 00:01:06.939 there? Could it be that we truly are alone? It's 00:01:06.939 --> 00:01:10.359 called the Fermi paradox and we'll take a detour 00:01:10.359 --> 00:01:13.319 into that and more in the second half of the 00:01:13.319 --> 00:01:16.439 show. Before I get into the night sky report 00:01:16.439 --> 00:01:18.920 for this week, I just have a quick update on 00:01:18.920 --> 00:01:22.140 the show website. If you're a new listener to 00:01:22.140 --> 00:01:24.760 the show, you might be wondering which other 00:01:24.760 --> 00:01:27.180 episodes would be good to go back and listen 00:01:27.180 --> 00:01:30.950 to. So, I've created a section on the website 00:01:30.950 --> 00:01:35.030 StarTrails .Show with resources for beginning 00:01:35.030 --> 00:01:39.150 astronomers and new listeners. On the site, you'll 00:01:39.150 --> 00:01:42.250 see a new option in the top menu called Start 00:01:42.250 --> 00:01:45.370 Here. On this page, you'll find a collection 00:01:45.370 --> 00:01:48.109 of my favorite episodes from the more than 80 00:01:48.109 --> 00:01:51.760 we've published since last year. Some of these 00:01:51.760 --> 00:01:55.180 are very much aimed at the new astronomer, while 00:01:55.180 --> 00:01:58.120 others cover topics that might be a bit off the 00:01:58.120 --> 00:02:01.920 wall but still thought -provoking. I've also 00:02:01.920 --> 00:02:05.180 compiled a collection of links that new astronomers 00:02:05.180 --> 00:02:08.280 might find helpful, from some of the stargazing 00:02:08.280 --> 00:02:12.259 apps I use to websites that are helpful for astronomers 00:02:12.259 --> 00:02:16.129 at any skill level. And, as always, if you have 00:02:16.129 --> 00:02:18.990 a question or comment about the show, you can 00:02:18.990 --> 00:02:22.310 use the contact form on the site to send me feedback. 00:02:22.930 --> 00:02:26.789 I really enjoy those listener questions. So with 00:02:26.789 --> 00:02:29.430 that announcement out of the way, let's see what's 00:02:29.430 --> 00:02:39.210 up in the sky this week. The moon begins as a 00:02:39.210 --> 00:02:42.169 slender, waxing crescent and grows brighter each 00:02:42.169 --> 00:02:45.229 night, reaching its first quarter phase on Wednesday. 00:02:46.009 --> 00:02:48.830 Early in the week, you'll still have dark evening 00:02:48.830 --> 00:02:51.949 skies, making it a prime time for faint objects 00:02:51.949 --> 00:02:56.830 and binocular or small -scope observing. By midweek, 00:02:57.030 --> 00:03:00.150 the moon will shine high at sunset and show off 00:03:00.150 --> 00:03:03.469 sharp craters and mountain ranges along the terminator, 00:03:03.930 --> 00:03:08.360 the line between lunar night and day. After that, 00:03:08.539 --> 00:03:11.780 the moon transitions into a waxing gibbous, staying 00:03:11.780 --> 00:03:15.500 up later into each night. That brighter moon 00:03:15.500 --> 00:03:19.139 may wash out faint deep sky targets, but it opens 00:03:19.139 --> 00:03:22.120 great opportunities for lunar surface photography 00:03:22.120 --> 00:03:27.199 or simply enjoying the moonlit landscape. Farther 00:03:27.199 --> 00:03:30.460 out, Saturn is still ruling the evening sky. 00:03:30.919 --> 00:03:34.139 You'll find it glowing a soft yellow -white in 00:03:34.139 --> 00:03:37.319 the southeast after sunset. climbing higher through 00:03:37.319 --> 00:03:40.460 the night. Even a modest telescope will reveal 00:03:40.460 --> 00:03:44.759 its rings and a few of its moons. Jupiter arises 00:03:44.759 --> 00:03:47.639 later, around mid -evening, and dominates the 00:03:47.639 --> 00:03:51.180 eastern sky. If you're up late or awake before 00:03:51.180 --> 00:03:55.139 dawn, it's one of the showstoppers. Mercury makes 00:03:55.139 --> 00:03:58.280 a fleeting appearance this week. On the 29th, 00:03:58.340 --> 00:04:01.259 it will reach its greatest eastern elongation. 00:04:01.319 --> 00:04:04.599 that's its furthest angular separation from the 00:04:04.599 --> 00:04:08.360 Sun in the evening sky. Keep a clear view toward 00:04:08.360 --> 00:04:11.819 the western horizon just after sunset, about 00:04:11.819 --> 00:04:15.680 30 or so minutes after sundown. If the sky is 00:04:15.680 --> 00:04:18.720 clear and the horizon is free of trees or buildings, 00:04:19.060 --> 00:04:23.139 you might spot the elusive twilight planet. Mars 00:04:23.139 --> 00:04:27.259 is fading low in the west after sunset and chasing 00:04:27.259 --> 00:04:31.129 into twilight. And Venus is now a morning star 00:04:31.129 --> 00:04:34.470 rising just before dawn in the east. It's worth 00:04:34.470 --> 00:04:43.009 a glance if you're an early riser. Our solar 00:04:43.009 --> 00:04:46.730 system is still hosting two special guests, and 00:04:46.730 --> 00:04:49.370 if you've been active on any astrophotography 00:04:49.370 --> 00:04:52.589 forums lately, you've probably seen some beautiful 00:04:52.589 --> 00:04:56.889 images of at least one of them. Our photogenic 00:04:56.889 --> 00:05:03.709 visitor is Comet C2025A6 or Comet Lemmon. Discovered 00:05:03.709 --> 00:05:06.269 earlier this year by the Mount Lemmon Survey, 00:05:06.810 --> 00:05:11.189 it's on a long -period orbit of roughly 1 ,150 00:05:11.189 --> 00:05:15.050 years. It's currently brightening and may be 00:05:15.050 --> 00:05:17.810 visible even with the naked eye under very dark 00:05:17.810 --> 00:05:21.089 skies, though binoculars will make it much easier 00:05:21.089 --> 00:05:24.879 to spot. For observers in North America, it's 00:05:24.879 --> 00:05:28.519 best after sunset in the northwest to west sky. 00:05:29.339 --> 00:05:32.420 It's low right now, but becoming more accessible. 00:05:33.060 --> 00:05:35.720 If you have a clear horizon, try locating it 00:05:35.720 --> 00:05:38.779 with binoculars in the constellation Boötes, 00:05:39.540 --> 00:05:42.019 a little more than five degrees northeast of 00:05:42.019 --> 00:05:45.449 Arcturus. And if you can't find it, just keep 00:05:45.449 --> 00:05:48.209 enjoying those stunning images other astronomers 00:05:48.209 --> 00:05:51.730 are capturing. It has a well -defined coma and 00:05:51.730 --> 00:05:54.589 a long tail that looks like it's shimmering in 00:05:54.589 --> 00:05:58.129 a cosmic breeze. The second visitor that has 00:05:58.129 --> 00:06:01.089 many people intrigued is interstellar object 00:06:01.089 --> 00:06:06.410 3I Atlas. This object arrived from outside our 00:06:06.410 --> 00:06:10.029 solar system and it just cruised past Mars a 00:06:10.029 --> 00:06:13.850 couple weeks ago. It's classified as an interstellar 00:06:13.850 --> 00:06:16.949 object because its trajectory is hyperbolic, 00:06:17.089 --> 00:06:21.029 meaning it's not bound to our Sun. And it's only 00:06:21.029 --> 00:06:24.470 the third such object like this we've ever recorded. 00:06:25.430 --> 00:06:27.649 Scientists are studying it carefully, though 00:06:27.649 --> 00:06:31.209 for backyard observers it's faint and difficult 00:06:31.209 --> 00:06:34.910 to spot. The buzz about it is largely thanks 00:06:34.910 --> 00:06:38.279 to its interstellar origins. You may have seen 00:06:38.279 --> 00:06:41.079 some of the speculation and conspiracies claiming 00:06:41.079 --> 00:06:45.060 it might be artificial or alien in origin, but 00:06:45.060 --> 00:06:48.060 mainstream science strongly supports the view 00:06:48.060 --> 00:06:51.360 that it's a natural body. So while it's a fascinating 00:06:51.360 --> 00:06:55.000 object to follow, keep your expectations grounded 00:06:55.000 --> 00:06:57.699 because it's not much to look at, at least right 00:06:57.699 --> 00:07:09.240 now. Now for the constellations and the quieter 00:07:09.240 --> 00:07:12.540 stars of fall. We've mentioned them in the past 00:07:12.540 --> 00:07:15.560 few episodes, but high overhead you'll find the 00:07:15.560 --> 00:07:19.019 Great Square of Pegasus, that large distinctive 00:07:19.019 --> 00:07:22.339 square shape marking the winged horse of myth. 00:07:23.120 --> 00:07:26.120 From its top corner you can trace a line northeast 00:07:26.120 --> 00:07:29.779 to the Andromeda Galaxy, our galactic neighbor. 00:07:30.579 --> 00:07:34.170 A pair of binoculars will help you find it. North 00:07:34.170 --> 00:07:37.310 of that, you'll find Cassiopeia, the queen of 00:07:37.310 --> 00:07:40.509 the northern sky, hanging high from mid -northern 00:07:40.509 --> 00:07:44.629 latitudes. Just below Cassiopeia lies one of 00:07:44.629 --> 00:07:47.930 my favorite binocular targets, the double cluster 00:07:47.930 --> 00:07:51.810 in Perseus, a pair of star clusters, bright and 00:07:51.810 --> 00:07:55.110 compact, easily enjoyed even in modest skies. 00:07:56.079 --> 00:07:59.319 The Milky Way isn't as obvious as it is in summer, 00:07:59.439 --> 00:08:02.079 but if you're under dark skies early in the week 00:08:02.079 --> 00:08:04.980 while the moon is still thin, you can trace its 00:08:04.980 --> 00:08:07.680 faint river starting south and moving through 00:08:07.680 --> 00:08:11.800 Cygnus, Cassiopeia, and into Perseus before it 00:08:11.800 --> 00:08:15.199 drifts into the northeast. It's a subtle beauty, 00:08:15.360 --> 00:08:18.639 less dramatic than the summer belt, but rewarding 00:08:18.639 --> 00:08:23.209 all the same. Meteor activity from the Orionids 00:08:23.209 --> 00:08:26.730 is tapering off, but don't rule out a stray meteor 00:08:26.730 --> 00:08:29.750 before dawn. If you're out late, keep a casual 00:08:29.750 --> 00:08:33.129 eye toward Orion rising in the east and you may 00:08:33.129 --> 00:08:36.850 catch a bright one. As always, to truly appreciate 00:08:36.850 --> 00:08:39.629 the fall sky, take a moment between targets. 00:08:39.809 --> 00:08:42.769 Let your eyes adapt to darkness for about 10 00:08:42.769 --> 00:08:46.169 to 15 minutes. With the heat of summer gone, 00:08:46.450 --> 00:08:49.590 the air is clearer and your view reaches farther. 00:08:50.950 --> 00:08:54.529 Next up, we'll step into that stillness more 00:08:54.529 --> 00:08:58.269 deeply, exploring the vast silence between the 00:08:58.269 --> 00:09:01.990 stars and why, in a universe so old and full 00:09:01.990 --> 00:09:05.190 of worlds, no one seems to be there to answer 00:09:05.190 --> 00:09:08.610 us. That's coming up after the break. Stay with 00:09:08.610 --> 00:09:26.529 us. Welcome back. There's a kind of silence in 00:09:26.529 --> 00:09:29.490 the cosmos that feels different from any other 00:09:29.490 --> 00:09:34.110 kind. It isn't peaceful or serene. It's unsettling. 00:09:34.690 --> 00:09:38.470 It's the silence of absence, the long echo of 00:09:38.470 --> 00:09:42.669 a question that's never been answered. We call 00:09:42.669 --> 00:09:46.070 it the Fermi paradox, the contradiction between 00:09:46.070 --> 00:09:50.669 how likely life seems to be and how alone we 00:09:50.669 --> 00:09:59.539 appear to be. In 1950, physicist Enrico Fermi 00:09:59.539 --> 00:10:02.240 was having lunch with colleagues at Los Alamos. 00:10:03.159 --> 00:10:06.299 The conversation turned to UFO sightings, and 00:10:06.299 --> 00:10:10.399 Fermi simply asked, where is everybody? It was 00:10:10.399 --> 00:10:13.600 both a joke and a revelation, because by that 00:10:13.600 --> 00:10:16.379 time, astronomers already knew the galaxy was 00:10:16.379 --> 00:10:19.740 ancient, 10 billion years older than the Earth, 00:10:20.259 --> 00:10:24.320 and vast beyond comprehension. Even if just a 00:10:24.320 --> 00:10:27.120 tiny fraction of those stars had planets and 00:10:27.120 --> 00:10:30.159 an even tinier fraction had life, shouldn't we 00:10:30.159 --> 00:10:34.399 see some sign of it? And keep in mind, at this 00:10:34.399 --> 00:10:37.320 point in astronomy we hadn't discovered a single 00:10:37.320 --> 00:10:40.580 exoplanet. That breakthrough was still more than 00:10:40.580 --> 00:10:45.440 40 years away. A decade after Fermi's question, 00:10:45.679 --> 00:10:48.179 astronomer Frank Drake tried to make sense of 00:10:48.179 --> 00:10:52.639 it mathematically. In 1961 he hosted a small 00:10:52.639 --> 00:10:55.179 meeting at the Green Bank Observatory in West 00:10:55.179 --> 00:10:58.279 Virginia, the first gathering devoted to the 00:10:58.279 --> 00:11:01.940 search for extraterrestrial intelligence. He 00:11:01.940 --> 00:11:04.899 scribbled a simple formula on a blackboard to 00:11:04.899 --> 00:11:07.899 structure their discussion, never imagining it 00:11:07.899 --> 00:11:12.000 would become iconic. That formula became the 00:11:12.000 --> 00:11:16.059 Drake Equation. It looks intimidating at a first 00:11:16.059 --> 00:11:19.259 glance, full of variables and symbols, but the 00:11:19.259 --> 00:11:22.919 idea is straightforward, and it's solvable using 00:11:22.919 --> 00:11:26.440 basic algebra, provided you can fill in the variables. 00:11:27.299 --> 00:11:31.360 Drake broke the problem into seven factors. How 00:11:31.360 --> 00:11:36.279 many stars form each year? What fraction of those 00:11:36.279 --> 00:11:39.399 have planets? How many of those worlds could 00:11:39.399 --> 00:11:42.980 support life? How many of those worlds indeed 00:11:42.980 --> 00:11:47.740 produce life? How often life develops intelligence? 00:11:48.600 --> 00:11:51.960 How often intelligent life develops technology? 00:11:52.860 --> 00:11:56.379 And finally, how long such civilizations can 00:11:56.379 --> 00:12:05.879 send detectable signals into space? Simply multiply 00:12:05.879 --> 00:12:08.820 those together and you get an estimate of how 00:12:08.820 --> 00:12:12.039 many civilizations might be communicating right 00:12:12.039 --> 00:12:18.779 now in the Milky Way. But the genius of the equation 00:12:18.779 --> 00:12:22.840 wasn't its precision, it was its humility. It 00:12:22.840 --> 00:12:27.000 showed us exactly where our ignorance lay. Every 00:12:27.000 --> 00:12:30.159 variable is a mystery to be solved and each new 00:12:30.159 --> 00:12:34.620 discovery exoplanets, biosignatures, radio surveys, 00:12:35.159 --> 00:12:38.919 tightened the numbers a little more. Right now, 00:12:39.080 --> 00:12:42.559 if you plug some hopeful numbers into the equation, 00:12:42.879 --> 00:12:45.860 you might get a few dozen civilizations in our 00:12:45.860 --> 00:12:50.080 galaxy right now. If you use more careful or 00:12:50.080 --> 00:12:53.000 skeptical numbers, you might end up with a number 00:12:53.000 --> 00:12:56.799 less than one, meaning we could be the only ones 00:12:56.799 --> 00:13:00.899 here at this moment. The problem is, most of 00:13:00.899 --> 00:13:03.679 the numbers in the equation are giant question 00:13:03.679 --> 00:13:07.580 marks. We don't know how often life begins, how 00:13:07.580 --> 00:13:11.519 often it becomes intelligent, or how long a civilization 00:13:11.519 --> 00:13:15.159 like ours stays detectable before it disappears. 00:13:16.220 --> 00:13:19.799 The math is strangely easy. It's the facts we 00:13:19.799 --> 00:13:24.679 don't have. Drake didn't stop there. He also 00:13:24.679 --> 00:13:28.950 co -founded Project Osma. the first modern SETI 00:13:28.950 --> 00:13:32.049 experiment using the Green Bank Telescope to 00:13:32.049 --> 00:13:35.330 listen for radio signals from two nearby stars. 00:13:36.610 --> 00:13:39.690 The effort was modest, just a few months of listening, 00:13:39.850 --> 00:13:44.210 but it sparked something profound. Soon after 00:13:44.210 --> 00:13:46.909 came the idea that we shouldn't just listen, 00:13:47.169 --> 00:13:52.669 but speak. In 1974, the Arecibo message was transmitted 00:13:52.669 --> 00:13:56.879 toward the globular cluster M13. a tightly packed 00:13:56.879 --> 00:14:05.139 group of stars 25 ,000 light years away. The 00:14:05.139 --> 00:14:08.759 signal, composed entirely of binary digits, encoded 00:14:08.759 --> 00:14:11.720 the numbers 1 through 10, the elements essential 00:14:11.720 --> 00:14:16.419 to life, DNA's double helix, a stick figure representing 00:14:16.419 --> 00:14:20.440 a human, the solar system, and the Arecibo telescope 00:14:20.440 --> 00:14:24.240 itself. It was symbolic more than practical. 00:14:24.590 --> 00:14:27.909 By the time the signal arrives, M13 will have 00:14:27.909 --> 00:14:31.409 drifted away. But it was a statement. We are 00:14:31.409 --> 00:14:40.250 here. A few years before Arecibo, in 1972 and 00:14:40.250 --> 00:14:45.190 73, NASA's Pioneer 10 and 11 spacecraft became 00:14:45.190 --> 00:14:48.070 the first human -made objects to leave the solar 00:14:48.070 --> 00:14:51.779 system. Each carried a small aluminum plaque 00:14:51.779 --> 00:14:54.860 etched with a map of our location in the galaxy 00:14:54.860 --> 00:14:58.379 and the image of a man and woman greeting whoever 00:14:58.379 --> 00:15:02.820 might find it. The Voyager 1 and 2 spacecraft 00:15:02.820 --> 00:15:06.360 went further. Each carried a gold -plated record 00:15:06.360 --> 00:15:09.779 sealed against time containing music from Bach 00:15:09.779 --> 00:15:13.279 to Chuck Berry, greetings in dozens of languages 00:15:13.279 --> 00:15:17.179 and sounds of our planet such as wind, rain, 00:15:17.419 --> 00:15:21.330 laughter. thunder, bird song, and even the heartbeat 00:15:21.330 --> 00:15:25.370 of a mother and child. Together, these were our 00:15:25.370 --> 00:15:28.929 cosmic time capsules, drifting ever outward at 00:15:28.929 --> 00:15:32.529 17 kilometers per second, bearing a message for 00:15:32.529 --> 00:15:36.190 listeners we may never meet. We covered the Golden 00:15:36.190 --> 00:15:39.909 Record in episode 52 and included many sounds 00:15:39.909 --> 00:15:42.389 from it in the episode, so go back and check 00:15:42.389 --> 00:15:46.769 it out if you missed it. By the 1990s, the search 00:15:46.769 --> 00:15:51.529 took a new form. digital crowdsourcing. The SETI 00:15:51.529 --> 00:15:55.169 at Home project turned ordinary computers into 00:15:55.169 --> 00:15:59.490 a distributed radio telescope. Millions of volunteers, 00:15:59.710 --> 00:16:02.450 and I was one of them and maybe you were too, 00:16:03.149 --> 00:16:05.809 downloaded screensavers that processed chunks 00:16:05.809 --> 00:16:08.950 of data collected by the Arecibo Observatory, 00:16:09.370 --> 00:16:12.409 searching for narrow -band signals that might 00:16:12.409 --> 00:16:17.250 indicate alien transmissions. For two decades 00:16:17.250 --> 00:16:20.590 it quietly scanned billions of frequencies running 00:16:20.590 --> 00:16:23.809 in the background on computers around the world. 00:16:24.450 --> 00:16:27.590 Humans, united by curiosity, gave their idle 00:16:27.590 --> 00:16:30.809 CPU cycles to the search for cosmic company. 00:16:31.570 --> 00:16:34.850 It was science as global collaboration and the 00:16:34.850 --> 00:16:37.909 largest volunteer computing project in history. 00:16:39.509 --> 00:16:43.490 Sadly, SETI at home never discovered any alien 00:16:43.490 --> 00:16:46.940 signals. The program went into hibernation in 00:16:46.940 --> 00:16:50.840 2020, but its legacy continues in new AI -driven 00:16:50.840 --> 00:16:54.059 searches like Breakthrough Listen, which now 00:16:54.059 --> 00:16:57.059 monitors billions of stars with unprecedented 00:16:57.059 --> 00:17:02.500 sensitivity. And yet the silence persists. Which 00:17:02.500 --> 00:17:05.160 brings us back to Fermi's haunting question. 00:17:05.759 --> 00:17:09.259 Some have speculated a great filter, a stage 00:17:09.259 --> 00:17:12.519 in evolution so perilous that few make it past. 00:17:12.920 --> 00:17:16.460 Perhaps intelligence carries the seeds of its 00:17:16.460 --> 00:17:20.059 own destruction. Ecological collapse, nuclear 00:17:20.059 --> 00:17:23.599 war, or even artificial intelligence run amok. 00:17:24.680 --> 00:17:28.140 If the filter lies behind us, we're lucky. If 00:17:28.140 --> 00:17:31.019 it lies ahead, the silence may be a warning. 00:17:35.180 --> 00:17:39.559 Others suggest more poetic explanations. Maybe 00:17:39.559 --> 00:17:42.640 civilizations retreat inward, turning to virtual 00:17:42.640 --> 00:17:46.380 worlds richer than reality itself. Maybe they 00:17:46.380 --> 00:17:49.339 transcend physical space altogether, existing 00:17:49.339 --> 00:17:52.960 as patterns of energy or information. Or maybe 00:17:52.960 --> 00:17:56.700 the galaxy is a dark forest where every civilization 00:17:56.700 --> 00:17:59.920 hides in terror, knowing that to announce their 00:17:59.920 --> 00:18:03.869 presence might invite annihilation. In that sense, 00:18:04.349 --> 00:18:08.369 silence isn't failure, it's a strategy. And then 00:18:08.369 --> 00:18:11.069 there's the humbling possibility that we simply 00:18:11.069 --> 00:18:14.710 don't know how to listen. Alien intelligence 00:18:14.710 --> 00:18:17.750 might communicate in ways beyond our comprehension, 00:18:18.369 --> 00:18:21.809 through neutrinos or gravitational waves or quantum 00:18:21.809 --> 00:18:24.829 entanglement. Their language could be encoded 00:18:24.829 --> 00:18:28.799 in magnetic fields or stellar oscillations. To 00:18:28.799 --> 00:18:32.079 them, our radio beacons might be as primitive 00:18:32.079 --> 00:18:39.119 as cave paintings. Personally, I believe in the 00:18:39.119 --> 00:18:43.880 simplest explanation. Space is unimaginably vast. 00:18:44.940 --> 00:18:48.279 The nearest star, Proxima Centauri, is more than 00:18:48.279 --> 00:18:51.680 four light years away. That's about 25 trillion 00:18:51.680 --> 00:18:55.359 miles. Even if we sent a message traveling at 00:18:55.359 --> 00:18:57.819 light speed, it would take more than eight years 00:18:57.819 --> 00:19:01.039 for a round -trip conversation. And that's our 00:19:01.039 --> 00:19:04.180 closest neighbor. The rest of the galaxy stretches 00:19:04.180 --> 00:19:09.079 across a hundred thousand light years. Also, 00:19:09.599 --> 00:19:12.619 radio waves, like light, weaken as they travel. 00:19:13.160 --> 00:19:15.940 What begins as a clear signal near its source 00:19:15.940 --> 00:19:19.640 dissolves into noise over cosmic distances. If 00:19:19.640 --> 00:19:22.500 you're involved in ham radio, you've likely seen 00:19:22.500 --> 00:19:25.259 signals fade dramatically over just hundreds 00:19:25.259 --> 00:19:29.319 of miles. The signals that escape Earth fade 00:19:29.319 --> 00:19:32.140 into the background hum of the universe long 00:19:32.140 --> 00:19:34.640 before they reach most of the stars we dream 00:19:34.640 --> 00:19:37.700 about. It's not like the beginning of the movie 00:19:37.700 --> 00:19:40.660 Contact, where we zoom into the solar system 00:19:40.660 --> 00:19:44.819 from light years away, hearing our earliest broadcasts 00:19:44.819 --> 00:19:47.420 echo through the void as clear as they were the 00:19:47.420 --> 00:19:51.819 day they were made. It's entirely possible that 00:19:51.819 --> 00:19:55.019 the cosmos is teeming with voices each calling 00:19:55.019 --> 00:19:58.400 out into the dark But none strong enough to bridge 00:19:58.400 --> 00:20:02.500 the gulf between them a million lonely transmitters 00:20:02.500 --> 00:20:08.180 all speaking all unheard Maybe the idea of that 00:20:08.180 --> 00:20:11.500 loneliness creates a feeling of existential dread 00:20:11.500 --> 00:20:14.829 and here's another eerie Halloween thought When 00:20:14.829 --> 00:20:17.609 you look up, much of the starlight falling on 00:20:17.609 --> 00:20:20.589 your eyes began its journey long before humans 00:20:20.589 --> 00:20:24.990 even existed. It crossed unimaginable distances, 00:20:25.349 --> 00:20:28.890 unbothered by our loneliness, carrying no reply, 00:20:29.529 --> 00:20:35.829 just photons from ancient suns. And the silence 00:20:35.829 --> 00:20:39.450 isn't nothing. The quiet between the stars may 00:20:39.450 --> 00:20:42.900 be the most profound message of all. A reminder 00:20:42.900 --> 00:20:45.900 that the universe is vast enough to contain both 00:20:45.900 --> 00:20:50.819 our fears and our hopes, our solitude and our 00:20:50.819 --> 00:20:57.450 longing. If the stars spoke to you this week 00:20:57.450 --> 00:20:59.769 or if a question's been on your mind, I'd love 00:20:59.769 --> 00:21:03.289 to hear it. Visit StarTrails .Show where you 00:21:03.289 --> 00:21:06.970 can contact me and explore past episodes. Be 00:21:06.970 --> 00:21:10.309 sure to follow Star Trails on Blue Sky and YouTube. 00:21:10.750 --> 00:21:13.690 Links are in the show notes. Until we meet again 00:21:13.690 --> 00:21:16.190 beneath the stars, clear skies everyone.