1 00:00:00,000 --> 00:00:11,680 Howdy stargazers and welcome to this episode of Star Trails. 2 00:00:11,680 --> 00:00:17,520 I'm Drew and I'll be your guide to the night sky for the week starting February 16th through 3 00:00:17,520 --> 00:00:19,400 the 22nd. 4 00:00:19,400 --> 00:00:24,480 This week Venus takes center stage as it approaches peak brightness. 5 00:00:24,480 --> 00:00:28,840 We'll discuss the phases of Venus and why its brightness fluctuates over the course 6 00:00:28,840 --> 00:00:30,280 of a year. 7 00:00:30,280 --> 00:00:37,360 Plus we'll examine one of astronomy's oldest mysteries, the ashen light of Venus. 8 00:00:37,360 --> 00:00:42,680 Later in the show we'll hop aboard the Voyager space probes and listen to the Voyager Golden 9 00:00:42,680 --> 00:00:49,560 Record, humanity's message in a bottle that's still adrift in the cosmic ocean. 10 00:00:49,560 --> 00:00:53,800 But first let's start with what you can see from your backyard this week. 11 00:00:53,800 --> 00:00:59,480 So grab a comfortable spot under the night sky and let's get started. 12 00:00:59,480 --> 00:01:05,480 Our moon starts the week in a waning gibbous phase, gradually decreasing in illumination 13 00:01:05,480 --> 00:01:06,920 each night. 14 00:01:06,920 --> 00:01:13,640 By the 20th the moon will enter its third quarter with exactly half of the surface illuminated. 15 00:01:13,640 --> 00:01:18,880 During this period the moon rises relatively late around midnight so you'll have darker 16 00:01:18,880 --> 00:01:26,880 skies to chase down those dimmer objects such as nebula, galaxies, and star clusters. 17 00:01:26,880 --> 00:01:32,440 Saturn is becoming challenging to observe as it moves closer to the sun's glare. 18 00:01:32,440 --> 00:01:38,800 By mid-February it appears low in the western sky shortly after sunset and sets within a 19 00:01:38,800 --> 00:01:41,000 couple hours. 20 00:01:41,000 --> 00:01:46,800 On February 16th Venus will reach its peak brightness for the year, shining at a very 21 00:01:46,800 --> 00:01:50,960 bright magnitude of negative 4.2. 22 00:01:50,960 --> 00:01:57,080 It will be prominently visible in the western sky after sunset, remaining observable for 23 00:01:57,080 --> 00:01:59,640 several hours into the evening. 24 00:01:59,640 --> 00:02:05,840 This is an ideal opportunity for observation as it will outshine all other celestial objects 25 00:02:05,840 --> 00:02:08,000 except the moon. 26 00:02:08,000 --> 00:02:12,320 Jupiter will be high overhead in the evening sky, appearing very bright. 27 00:02:12,320 --> 00:02:18,160 It's an excellent time to observe the planet's features and its Galilean moons through a 28 00:02:18,160 --> 00:02:23,720 telescope, and because it's high in the sky there's less atmospheric turbulence, resulting 29 00:02:23,720 --> 00:02:25,960 in a clearer view. 30 00:02:25,960 --> 00:02:31,920 Mars continues to be visible in the evening sky, located in Gemini, high in the east after 31 00:02:31,920 --> 00:02:33,440 sunset. 32 00:02:33,440 --> 00:02:40,600 Its reddish hue makes it distinguishable from other celestial objects nearby. 33 00:02:40,600 --> 00:02:47,640 While a complete 7-planet alignment, including Mercury, is expected around February 23rd, 34 00:02:47,640 --> 00:02:54,040 this week you can still observe a notable alignment of Venus, Mars, Jupiter, and Saturn, 35 00:02:54,040 --> 00:02:59,040 all following the ecliptic plane across the evening sky. 36 00:02:59,040 --> 00:03:04,760 Uranus and Neptune are also positioned along this arc but require binoculars or a telescope 37 00:03:04,760 --> 00:03:06,720 to view. 38 00:03:06,720 --> 00:03:12,280 As always, for optimal viewing, find a location with minimal light pollution and a clear view 39 00:03:12,280 --> 00:03:14,160 of the horizon. 40 00:03:14,160 --> 00:03:19,400 Using a stargazing app can help you identify and locate these celestial objects in the 41 00:03:19,400 --> 00:03:26,240 night sky. 42 00:03:26,240 --> 00:03:30,440 As Venus is on its way to peak brightness this week, I thought I'd take a moment to 43 00:03:30,440 --> 00:03:36,160 offer up some viewing tips for our planetary neighbor, which is often referred to as the 44 00:03:36,160 --> 00:03:41,200 evening star or morning star, depending on its visibility. 45 00:03:41,200 --> 00:03:45,240 If you've never looked at Venus through a telescope, you may be surprised to learn it 46 00:03:45,240 --> 00:03:49,240 exhibits phases, much like our moon. 47 00:03:49,240 --> 00:03:55,280 This cycle was first recorded by Galileo in the early 17th century and provided crucial 48 00:03:55,280 --> 00:04:01,760 evidence for the heliocentric or sun-centered model of the solar system. 49 00:04:01,760 --> 00:04:05,800 Through a telescope, you'll notice that Venus is quite dynamic. 50 00:04:05,800 --> 00:04:13,200 It changes both in shape and apparent size over time, going through the following phases. 51 00:04:13,200 --> 00:04:19,440 Full Venus occurs at superior conjunction, when Venus is on the far side of the sun, 52 00:04:19,440 --> 00:04:22,880 completely illuminated but appearing small and distant. 53 00:04:22,880 --> 00:04:28,360 It's also in the sun's glare, making it more difficult to see. 54 00:04:28,360 --> 00:04:33,760 As Venus moves along its orbit toward Earth, we begin to see a shadowed portion similar 55 00:04:33,760 --> 00:04:36,520 to a waxing or waning moon. 56 00:04:36,520 --> 00:04:39,480 This is the gibbous phase. 57 00:04:39,480 --> 00:04:45,400 Half Venus occurs when it reaches greatest elongation, meaning it appears at its farthest 58 00:04:45,400 --> 00:04:49,440 angular distance from the sun in the sky. 59 00:04:49,440 --> 00:04:55,480 As Venus moves closer to Earth, the illuminated portion shrinks into a crescent, but the planet 60 00:04:55,480 --> 00:04:59,040 itself appears much larger in our sky. 61 00:04:59,040 --> 00:05:02,400 This phase is called crescent Venus. 62 00:05:02,400 --> 00:05:08,520 A new Venus, or inferior conjunction, occurs when it passes directly between the Earth 63 00:05:08,520 --> 00:05:14,960 and Sun, appearing as a dark silhouette against the solar disk if perfectly aligned, which 64 00:05:14,960 --> 00:05:19,280 is a rare event known as a transit of Venus. 65 00:05:19,280 --> 00:05:25,520 Then the cycle reverses as Venus moves back toward the far side of the sun. 66 00:05:25,520 --> 00:05:31,040 The phases of Venus occur because of its orbit around the sun and our changing perspective 67 00:05:31,040 --> 00:05:32,640 from Earth. 68 00:05:32,640 --> 00:05:38,160 Unlike the moon, which orbits Earth, Venus orbits the sun in an inner orbit, meaning 69 00:05:38,160 --> 00:05:42,520 that it moves between us and the sun periodically. 70 00:05:42,520 --> 00:05:48,960 This causes different portions of its sunlit side to be visible at different times. 71 00:05:48,960 --> 00:05:53,720 Galileo's observations of these phases were groundbreaking because they disproved the 72 00:05:53,720 --> 00:05:57,560 old geocentric model of the solar system. 73 00:05:57,560 --> 00:06:03,880 If Earth were at the center, Venus would not show the full range of phases. 74 00:06:03,880 --> 00:06:08,240 Even though Venus is fully illuminated when it's on the far side of the sun, it appears 75 00:06:08,240 --> 00:06:12,680 smaller and dimmer because of its greater distance from us. 76 00:06:12,680 --> 00:06:17,640 Conversely, when it's in its crescent phase and closer to Earth, it appears much larger 77 00:06:17,640 --> 00:06:19,240 and brighter. 78 00:06:19,240 --> 00:06:25,560 This is why Venus shines most brilliantly as a thin crescent just before or after inferior 79 00:06:25,560 --> 00:06:27,200 conjunction. 80 00:06:27,200 --> 00:06:33,400 The complete cycle of Venus' phases from full to crescent and back to full takes about 81 00:06:33,400 --> 00:06:35,400 19 months. 82 00:06:35,400 --> 00:06:41,040 This corresponds to Venus' synodic period, which is the time it takes for Venus to return 83 00:06:41,040 --> 00:06:45,520 to the same position relative to the sun as seen from Earth. 84 00:06:45,520 --> 00:06:51,800 However, each phase does not last an equal amount of time because Venus' movement is 85 00:06:51,800 --> 00:06:56,520 more apparent when it's closer to Earth and slower when it's farther away. 86 00:06:56,520 --> 00:06:58,840 Here's a breakdown. 87 00:06:58,840 --> 00:07:06,640 Full Venus to half Venus' de Gibbes phase lasts about 146 days as Venus moves from 88 00:07:06,640 --> 00:07:12,280 fully illuminated but far away to when it appears half lit. 89 00:07:12,280 --> 00:07:18,920 Half Venus to crescent Venus takes about 72 days as Venus moves towards Earth and its 90 00:07:18,920 --> 00:07:21,680 crescent becomes thinner. 91 00:07:21,680 --> 00:07:27,840 Crescent Venus to new Venus is much quicker, taking about 36 days since Venus is moving 92 00:07:27,840 --> 00:07:31,960 rapidly in its closer inner orbit. 93 00:07:31,960 --> 00:07:38,720 These phases are the same lengths but in reverse as Venus cycles back to full, new Venus to 94 00:07:38,720 --> 00:07:43,160 crescent crescent to half, and so on. 95 00:07:43,160 --> 00:07:49,200 Venus Watchers may also want to try chasing down the elusive Ashen light. 96 00:07:49,200 --> 00:07:53,640 It's one of the most mysterious phenomena in planetary astronomy. 97 00:07:53,640 --> 00:07:59,760 Some observers have reported seeing a faint glow on the dark side of Venus, the side not 98 00:07:59,760 --> 00:08:02,480 directly illuminated by the sun. 99 00:08:02,480 --> 00:08:06,480 No one knows what causes it or if it's even real. 100 00:08:06,480 --> 00:08:12,600 Unlike Earth's shine, where sunlight reflects off of Earth to softly illuminate the moon's 101 00:08:12,600 --> 00:08:18,800 surface, Venus has no nearby celestial body to provide this kind of light. 102 00:08:18,800 --> 00:08:26,280 Yet for centuries, astronomers have claimed to see a dim glow on Venus' shadowed side. 103 00:08:26,280 --> 00:08:28,960 There are several unconfirmed theories. 104 00:08:28,960 --> 00:08:35,520 One possibility is air glow, a faint emission of light from chemical reactions in Venus' 105 00:08:35,520 --> 00:08:39,880 dense atmosphere, similar to Earth's auroras. 106 00:08:39,880 --> 00:08:41,680 Another idea is lightning. 107 00:08:41,680 --> 00:08:47,400 Some researchers suspect that massive electrical storms could be producing the glow, but so 108 00:08:47,400 --> 00:08:51,600 far we haven't detected lightning on Venus. 109 00:08:51,600 --> 00:08:57,760 Other theories suggest volcanic activity where glowing lava or atmospheric reactions might 110 00:08:57,760 --> 00:09:00,440 illuminate the planet's dark side. 111 00:09:00,440 --> 00:09:06,080 Some believe it's simply an optical illusion caused by the bright crescent of Venus tricking 112 00:09:06,080 --> 00:09:07,880 the human eye. 113 00:09:07,880 --> 00:09:14,480 And there's the idea of scattered sunlight where Venus' thick cloud cover might be redirecting 114 00:09:14,480 --> 00:09:17,720 light in unexpected ways. 115 00:09:17,720 --> 00:09:22,480 It's not easy to spot the ash and light, but if you want to try, you'll need the right 116 00:09:22,480 --> 00:09:23,920 conditions. 117 00:09:23,920 --> 00:09:29,600 The best time to observe it is when Venus is in its crescent phase, just before or after 118 00:09:29,600 --> 00:09:31,000 new Venus. 119 00:09:31,000 --> 00:09:34,200 That's when the dark side is most visible. 120 00:09:34,200 --> 00:09:40,640 To have the best chance, use a high-quality telescope, at least 4-6 inches in aperture, 121 00:09:40,640 --> 00:09:44,400 and try observing from a very dark location. 122 00:09:44,400 --> 00:09:50,600 Using averted vision, where you look slightly off to the side instead of directly at Venus, 123 00:09:50,600 --> 00:09:54,120 can sometimes make faint details more noticeable. 124 00:09:54,120 --> 00:10:00,080 And if you're into astrophotography, long exposure images and stacking techniques might 125 00:10:00,080 --> 00:10:03,200 reveal something your eyes can't. 126 00:10:03,200 --> 00:10:09,240 The ash and light has been reported as far back as the 1600s and even famous astronomers 127 00:10:09,240 --> 00:10:13,240 like Sir William Herschel claim to have seen it. 128 00:10:13,240 --> 00:10:19,720 Most recently, NASA's Parker Solar Probe, which made a series of flybys of Venus, seemed 129 00:10:19,720 --> 00:10:23,560 to confirm a glow in the visible spectrum. 130 00:10:23,560 --> 00:10:30,640 In the near-infrared spectrum, Venus's hot surface glows like iron pulled from a forge. 131 00:10:30,640 --> 00:10:36,200 Its thought some of this glow also creeps into the visible spectrum, and if cloud cover 132 00:10:36,200 --> 00:10:41,640 is translucent, perhaps we can see some of that surface glow. 133 00:10:41,640 --> 00:10:46,320 Whatever the answer may be, the ash and light remains one of the great unsolved mysteries 134 00:10:46,320 --> 00:10:47,880 of Venus. 135 00:10:47,880 --> 00:10:53,000 If you ever manage to catch a glimpse of it, you'll be joining a long history of observers 136 00:10:53,000 --> 00:11:04,360 trying to unlock one of the solar system's greatest secrets. 137 00:11:04,360 --> 00:11:10,840 A lone spacecraft drifts through the void, further from Earth than any human-made object 138 00:11:10,840 --> 00:11:12,560 has ever traveled. 139 00:11:12,560 --> 00:11:17,800 It carries no crew, no passengers, except perhaps a message. 140 00:11:17,800 --> 00:11:24,680 A golden disk designed to last a billion years, etched with the sounds and sights of an entire 141 00:11:24,680 --> 00:11:26,240 planet. 142 00:11:26,240 --> 00:11:34,160 This artifact is the Voyager Golden Record, humanity's time capsule for the universe. 143 00:11:34,160 --> 00:11:41,160 We know full well that our planet and all its inhabitants are about a small part of this 144 00:11:41,160 --> 00:11:47,800 immense universe that surrounds us, and it is with humility and hope that we take this 145 00:11:47,800 --> 00:11:48,800 step. 146 00:11:48,800 --> 00:11:55,240 We'll take a look at the science, technology, and ingenuity that went into crafting this 147 00:11:55,240 --> 00:11:57,080 interstellar greeting. 148 00:11:57,080 --> 00:12:02,400 But to understand why the Golden Record exists, we have to start with the spacecraft carrying 149 00:12:02,400 --> 00:12:06,560 it, Voyager 1 and 2. 150 00:12:06,560 --> 00:12:12,960 In the early 1970s, NASA was preparing for one of the most ambitious missions in history. 151 00:12:12,960 --> 00:12:18,560 The space probes Voyager 1 and 2 were designed to explore the outer planets of the solar 152 00:12:18,560 --> 00:12:27,440 system, using a rare planetary alignment that occurs only once every 175 years. 153 00:12:27,440 --> 00:12:32,600 But as these robotic explorers were being prepared for launch, a small team of scientists 154 00:12:32,600 --> 00:12:39,360 and visionaries saw an even greater opportunity to attach a message for any future finders 155 00:12:39,360 --> 00:12:42,320 of the spacecraft. 156 00:12:42,320 --> 00:12:46,440 The idea of sending an interstellar message wasn't new. 157 00:12:46,440 --> 00:12:54,480 Pioneer 10 and 11 launched in 1972 and 1973 carried a small engraved plaque designed by 158 00:12:54,480 --> 00:13:01,360 Carl Sagan and Frank Drake, which depicted the location of Earth and a basic representation 159 00:13:01,360 --> 00:13:03,840 of humans. 160 00:13:03,840 --> 00:13:09,320 But the team wanted something more sophisticated for the Voyagers, something that could convey 161 00:13:09,320 --> 00:13:16,200 sights, sounds, and emotions from our world. 162 00:13:16,200 --> 00:13:22,840 The idea for the Golden Record was championed by Sagan, an astrophysicist, planetary scientist, 163 00:13:22,840 --> 00:13:27,160 and one of the greatest science communicators of his time. 164 00:13:27,160 --> 00:13:32,800 He believed deeply in the idea of sending a message to the stars, not because he thought 165 00:13:32,800 --> 00:13:39,120 aliens were likely to find it, but because it was a powerful symbol of human curiosity 166 00:13:39,120 --> 00:13:41,320 and optimism. 167 00:13:41,320 --> 00:13:45,360 Here's Sagan in his own words, describing the project. 168 00:13:45,360 --> 00:13:50,920 Voyager's passage by Jupiter accelerated it towards a close encounter with the planet 169 00:13:50,920 --> 00:13:51,920 Saturn. 170 00:13:51,920 --> 00:13:55,160 Saturn's gravity will propel it onto Uranus. 171 00:13:55,160 --> 00:14:01,800 And in this game of cosmic billiards after Uranus, it will plunge on past Neptune, leaving 172 00:14:01,800 --> 00:14:08,920 the solar system and becoming an interstellar spacecraft, destined to wander forever, the 173 00:14:08,920 --> 00:14:11,080 great ocean between the stars. 174 00:14:11,080 --> 00:14:19,000 And a Voyager should sometime in its distant future encounter beings from some other civilization 175 00:14:19,000 --> 00:14:20,560 in space. 176 00:14:20,560 --> 00:14:29,720 It bears a message, a phonograph, golden, delicate, with instructions for use. 177 00:14:29,720 --> 00:14:35,800 And on this record are a sampling of pictures, sounds, greetings, and an hour and a half 178 00:14:35,800 --> 00:14:37,800 of exquisite music. 179 00:14:37,800 --> 00:14:40,480 The Earth's greatest hits. 180 00:14:40,480 --> 00:14:47,680 A gift across the cosmic ocean from one island of civilization to another. 181 00:14:47,680 --> 00:14:53,960 And NASA approved the idea, but Sagan and his team had just six weeks to design the record 182 00:14:53,960 --> 00:14:58,960 and near impossible deadline for a project of this scope. 183 00:14:58,960 --> 00:15:04,160 Members of Sagan's team for this undertaking again included Frank Drake, famous for the 184 00:15:04,160 --> 00:15:11,440 Drake equation, which estimates the probability of extraterrestrial life in the universe. 185 00:15:11,440 --> 00:15:17,120 Andruyan later, Sagan's wife, served as creative director of the project. 186 00:15:17,120 --> 00:15:20,360 She selected much of the music and sounds. 187 00:15:20,360 --> 00:15:26,760 Timothy Ferris, a science writer and journalist, produced the final version of the audio recordings. 188 00:15:26,760 --> 00:15:31,120 Artist and designer John Lomburg helped curate the images. 189 00:15:31,120 --> 00:15:37,640 And Linda Sagan, Carl Sagan's then wife, worked on the spoken greetings and messages. 190 00:15:37,640 --> 00:15:43,040 The team's mission was straightforward, represent all of humanity. 191 00:15:43,040 --> 00:15:47,320 Sagan and his team wanted the record to be a true reflection of Earth's cultures and 192 00:15:47,320 --> 00:15:49,040 civilizations. 193 00:15:49,040 --> 00:15:54,360 This meant including not just Western music and languages, but a broad range of human 194 00:15:54,360 --> 00:15:56,080 diversity. 195 00:15:56,080 --> 00:15:58,720 And it wasn't limited to sounds. 196 00:15:58,720 --> 00:16:03,600 Using the technology of the time, a selection of images were encoded in the message. 197 00:16:03,600 --> 00:16:08,040 We'll talk more about how that was accomplished in a moment. 198 00:16:08,040 --> 00:16:12,120 How do you even begin to decide what to include? 199 00:16:12,120 --> 00:16:16,880 With only six weeks, the team had to make incredibly difficult choices. 200 00:16:16,880 --> 00:16:24,160 Here's what made it onto the final record. 201 00:16:24,160 --> 00:16:25,360 Sounds of Earth. 202 00:16:25,360 --> 00:16:32,040 These included natural sounds like wind, rain, ocean waves, thunder and fire. 203 00:16:32,040 --> 00:16:39,000 Animal calls like whale song, birds and elephants. 204 00:16:39,000 --> 00:16:45,640 Human sounds such as footsteps, laughter, a baby crying and a kiss. 205 00:16:45,640 --> 00:16:57,200 There are also spoken greetings in 55 languages ranging from English to ancient Sumerian. 206 00:16:57,200 --> 00:16:59,240 And this iconic greeting. 207 00:16:59,240 --> 00:17:03,640 Hello from the children of planet Earth. 208 00:17:03,640 --> 00:17:09,840 There's also a 90 minute playlist of global music, including examples of Western classical 209 00:17:09,840 --> 00:17:14,840 music. 210 00:17:14,840 --> 00:17:21,200 Traditional drumming from West Africa. 211 00:17:21,200 --> 00:17:28,360 Indigenous music such as these Peruvian pan pipes. 212 00:17:28,360 --> 00:17:37,520 And even modern American music, Louis Armstrong. 213 00:17:37,520 --> 00:17:48,200 Blind Willie Johnson. 214 00:17:48,200 --> 00:17:54,360 And Chuck Berry's Johnny B. Good, which Sagan notably had to fight to get included. 215 00:17:54,360 --> 00:18:08,400 A total of 116 color and black and white images were also included, ranging from illustrations 216 00:18:08,400 --> 00:18:13,520 of mathematical concepts to photos of humanity and nature. 217 00:18:13,520 --> 00:18:19,160 The first images on the record are scientific, simple binary numbers, chemical structures 218 00:18:19,160 --> 00:18:22,360 and mathematical relationships. 219 00:18:22,360 --> 00:18:29,880 And diagrams of DNA and human anatomy, the physics of gravity and planetary orbits. 220 00:18:29,880 --> 00:18:36,480 The human experience is represented by a mother nursing a child, a bustling city street, the 221 00:18:36,480 --> 00:18:43,920 Olympic sprinter Carl Lewis and Midge Stride, and finally Earth itself, forests, mountains, 222 00:18:43,920 --> 00:18:47,720 Great Wall of China and Taj Mahal. 223 00:18:47,720 --> 00:18:53,280 NASA knew that if Voyager continued its journey for millennia, it might one day be discovered 224 00:18:53,280 --> 00:18:55,160 by another civilization. 225 00:18:55,160 --> 00:18:58,120 But why a record? 226 00:18:58,120 --> 00:19:03,960 In 1977, this was still the preferred format for audio and music. 227 00:19:03,960 --> 00:19:07,960 Digital storage was still in its infancy when Voyager launched. 228 00:19:07,960 --> 00:19:13,160 Magnetic tape degraded quickly, hard drives were bulky and fragile. 229 00:19:13,160 --> 00:19:19,440 But a gold-plated copper record could last for millions, possibly even billions of years 230 00:19:19,440 --> 00:19:21,360 in space. 231 00:19:21,360 --> 00:19:27,440 Unlike digital formats, a record doesn't require special software to decode. 232 00:19:27,440 --> 00:19:33,720 Any intelligent species with an understanding of sound waves could reconstruct the information, 233 00:19:33,720 --> 00:19:39,680 just like we decode hieroglyphics or cuneiform tablets. 234 00:19:39,680 --> 00:19:42,880 Constructing a record player is remarkably simple. 235 00:19:42,880 --> 00:19:48,200 I think I learned this from Mr. Wizard's World when I was a kid, but I once rolled 236 00:19:48,200 --> 00:19:53,960 up a piece of construction paper into a cone shape and taped a sewing needle to the point 237 00:19:53,960 --> 00:19:55,480 of the cone. 238 00:19:55,480 --> 00:20:01,480 By placing this needle on a spinning record, I was able to hear some fairly tinny but recognizable 239 00:20:01,480 --> 00:20:04,920 sounds coming out of my paper speaker. 240 00:20:04,920 --> 00:20:09,320 And by the way, I wouldn't recommend doing this on a vinyl record nowadays because you'll 241 00:20:09,320 --> 00:20:11,160 likely damage it. 242 00:20:11,160 --> 00:20:14,120 The gold record isn't quite that fragile. 243 00:20:14,120 --> 00:20:16,880 It was made of gold-plated copper. 244 00:20:16,880 --> 00:20:20,800 Gold was chosen because it's highly resistant to corrosion. 245 00:20:20,800 --> 00:20:26,720 The record was designed to be played at about half the speed of a traditional LP at around 246 00:20:26,720 --> 00:20:29,680 16 revolutions per minute. 247 00:20:29,680 --> 00:20:32,280 This allows for a longer playtime. 248 00:20:32,280 --> 00:20:37,400 A pictorial cover provides instructions on how to decode the record and this cover is 249 00:20:37,400 --> 00:20:44,560 etched with a map designed by Frank Drake of known pulsars to show where Earth is located. 250 00:20:44,560 --> 00:20:50,640 A small amount of uranium is also embedded in the case, allowing an advanced civilization 251 00:20:50,640 --> 00:20:55,560 to determine the record's age using radioactive decay. 252 00:20:55,560 --> 00:21:00,680 The record also came with its own cartridge and needle, although the aliens would need 253 00:21:00,680 --> 00:21:07,000 to figure out a way to amplify the electrical signal generated by its stylus because speakers 254 00:21:07,000 --> 00:21:09,280 weren't included. 255 00:21:09,280 --> 00:21:12,680 So how are the images stored on the record? 256 00:21:12,680 --> 00:21:18,880 In 1977, there was no JPEG, PNG, or any sort of digital compression. 257 00:21:18,880 --> 00:21:25,920 Instead, NASA used an ingenious method, analog frequency modulation, which is similar to 258 00:21:25,920 --> 00:21:32,160 how early slow-scan television worked. 259 00:21:32,160 --> 00:21:35,960 That's what an encoded image sounds like. 260 00:21:35,960 --> 00:21:42,920 This image was scanned line by line, converting brightness levels into modulated frequencies. 261 00:21:42,920 --> 00:21:49,000 Dark areas have lower frequencies, bright areas have higher ones. 262 00:21:49,000 --> 00:21:54,400 The result is a sound that, when decoded properly, reveals a picture. 263 00:21:54,400 --> 00:22:00,280 The images are stored at 512 lines per picture, which is roughly the resolution of an early 264 00:22:00,280 --> 00:22:02,880 black-and-white television. 265 00:22:02,880 --> 00:22:07,200 The included color images required more processing. 266 00:22:07,200 --> 00:22:12,800 Instead of a single image, they were stored as three separate grayscale layers, red, green, 267 00:22:12,800 --> 00:22:17,640 and blue, which could be reconstructed into a full image. 268 00:22:17,640 --> 00:22:23,720 My ham radio brethren have likely heard of slow-scan TV. 269 00:22:23,720 --> 00:22:31,600 It's an antiquated but charming way to send images over radio waves. 270 00:22:31,600 --> 00:22:36,560 The amateur station on the International Space Station occasionally transmits images 271 00:22:36,560 --> 00:22:37,560 in this manner. 272 00:22:37,560 --> 00:22:44,160 In fact, they are scheduled to send slow-scan TV this week in celebration of World Radio 273 00:22:44,160 --> 00:22:45,160 Day. 274 00:22:45,160 --> 00:22:49,200 So if you have a receiver, try tuning in. 275 00:22:49,200 --> 00:22:54,480 The images on the Golden Record are encoded using a unique scheme that isn't compatible 276 00:22:54,480 --> 00:22:58,400 with any existing slow-scan TV standards. 277 00:22:58,400 --> 00:23:04,120 So assuming an alien species happened upon the record and recognized the structured modulation 278 00:23:04,120 --> 00:23:09,560 as data, they'd need to develop their own methodology for translating those sounds into 279 00:23:09,560 --> 00:23:11,320 images. 280 00:23:11,320 --> 00:23:16,360 If you're savvy with audio and programming, you can download the original audio and decode 281 00:23:16,360 --> 00:23:18,320 the images yourself. 282 00:23:18,320 --> 00:23:24,040 Fortunately, NASA maintains an archive of the original images so they're easily viewable 283 00:23:24,040 --> 00:23:25,040 online. 284 00:23:25,040 --> 00:23:29,080 I'll include links in the show notes. 285 00:23:29,080 --> 00:23:34,840 Sagan documented the process of creating the Golden Record in the 1978 book, Murmurs of 286 00:23:34,840 --> 00:23:38,200 Earth, the Voyager Interstellar Record. 287 00:23:38,200 --> 00:23:45,280 It's worth checking out if you want to learn more about how the record was created. 288 00:23:45,280 --> 00:23:50,840 To quote Sagan, the launching of this bottle into the cosmic ocean says something very 289 00:23:50,840 --> 00:23:54,520 hopeful about life on this planet. 290 00:23:54,520 --> 00:23:58,160 That message in a bottle is still adrift. 291 00:23:58,160 --> 00:24:03,360 After completing their planetary missions to study the gas giants, both voyagers continued 292 00:24:03,360 --> 00:24:04,360 outward. 293 00:24:04,360 --> 00:24:10,520 Today, they are in interstellar space beyond the influence of our sun's solar wind. 294 00:24:10,520 --> 00:24:15,760 At this moment, Voyager 1 is more than 15 billion miles from Earth. 295 00:24:15,760 --> 00:24:20,200 It takes radio signals more than 22 hours to reach it. 296 00:24:20,200 --> 00:24:25,360 If you recall our discussion of the scale of the cosmos from last week's episode, you'll 297 00:24:25,360 --> 00:24:29,280 know that space is an incredibly empty place. 298 00:24:29,280 --> 00:24:35,360 The chances of either Voyager encountering anything or anyone in their journey is slim 299 00:24:35,360 --> 00:24:38,200 but not impossible. 300 00:24:38,200 --> 00:24:47,840 Voyager 1 will pass within 1.6 light years of the star Glease 445 in about 40,000 years. 301 00:24:47,840 --> 00:24:53,640 If a civilization exists there, perhaps they'll detect it and hear the echoes of our distant 302 00:24:53,640 --> 00:24:57,280 Earth. 303 00:24:57,280 --> 00:24:59,480 If you enjoyed this episode, let me know. 304 00:24:59,480 --> 00:25:05,160 The easiest way to do that is by visiting our website, startrails.show. 305 00:25:05,160 --> 00:25:09,400 This is also a great way to share the show with friends, and you can find transcripts 306 00:25:09,400 --> 00:25:11,280 of every episode. 307 00:25:11,280 --> 00:25:16,080 You can find this on Blue Sky and Mastodon, and if you'd like to support the show by 308 00:25:16,080 --> 00:25:22,840 buying me a cup of coffee, be sure to visit the links in the show notes and on the website. 309 00:25:22,840 --> 00:25:27,000 Until next time, keep looking up and exploring the night sky. 310 00:25:27,000 --> 00:25:46,920 Dear Sky's Everyone!