1 00:00:04,066 --> 00:00:07,266 Ever since the dawn of humanity, 2 00:00:07,366 --> 00:00:11,166 the skies have influenced every part of our lives. 3 00:00:12,700 --> 00:00:14,600 They have helped us to navigate... 4 00:00:14,700 --> 00:00:17,866 For our ancestors, that was their neighborhood. 5 00:00:18,833 --> 00:00:20,333 To build... 6 00:00:20,433 --> 00:00:24,633 The pyramids are aligned precisely towards true north. 7 00:00:24,733 --> 00:00:29,433 And defined the very idea of time itself. 8 00:00:29,533 --> 00:00:31,533 When the sun crosses the horizon, boom! 9 00:00:31,633 --> 00:00:33,300 You know you've been waiting one year. 10 00:00:35,800 --> 00:00:39,933 To explain the movements of everything above us, 11 00:00:40,033 --> 00:00:44,500 we populated the cosmos with gods and monsters. 12 00:00:46,300 --> 00:00:48,033 The sky was understood 13 00:00:48,133 --> 00:00:49,933 as a kind of stone tablet 14 00:00:50,033 --> 00:00:53,400 on which the gods inscribed their messages. 15 00:00:53,500 --> 00:00:56,400 But as we looked deeper into the heavens... 16 00:00:57,933 --> 00:01:01,566 We turned away from belief in a mythical universe... 17 00:01:02,800 --> 00:01:05,100 To a radical new way of thinking. 18 00:01:05,200 --> 00:01:09,600 These phenomena cease to be linked to supernatural gods 19 00:01:09,700 --> 00:01:11,400 and instead become natural. 20 00:01:13,566 --> 00:01:16,333 This is the story of humankind's 21 00:01:16,433 --> 00:01:18,333 obsession with the skies... 22 00:01:19,800 --> 00:01:23,400 And the ways our ancestors made sense of the universe. 23 00:01:26,300 --> 00:01:29,833 This is the story of how we moved from a world 24 00:01:29,933 --> 00:01:31,966 ruled by supernatural beings... 25 00:01:33,233 --> 00:01:37,166 To a cosmos revealed by scientific astronomy. 26 00:01:39,100 --> 00:01:42,900 This is the story of seeing other worlds... 27 00:01:43,000 --> 00:01:46,133 And finding our true place among them. 28 00:01:46,233 --> 00:01:52,133 This is the story of our ancient skies. 29 00:02:16,266 --> 00:02:20,133 Today's technology allows us to see the universe 30 00:02:20,233 --> 00:02:24,266 in ways that were unimaginable even a few decades ago. 31 00:02:30,266 --> 00:02:34,200 We can observe far-off galaxies, millions of light-years away... 32 00:02:37,333 --> 00:02:40,566 Analyze the chemical composition of distant planets... 33 00:02:44,566 --> 00:02:47,066 And even witness the birth of stars. 34 00:02:48,966 --> 00:02:51,533 We know that the moon is orbiting the earth 35 00:02:51,633 --> 00:02:53,833 at 2,000 miles per hour... 36 00:02:57,066 --> 00:03:00,933 And that the myriad of pin-pricks of light in the night sky 37 00:03:01,033 --> 00:03:03,233 are giant burning suns, 38 00:03:03,333 --> 00:03:06,773 - perhaps each with its own set of planets. - Perhaps each with its own set of planets. 39 00:03:09,866 --> 00:03:12,400 The sky is no longer a mystery in the way it was 40 00:03:12,500 --> 00:03:15,666 to generation after generation that came before us. 41 00:03:20,500 --> 00:03:24,433 And yet, when we look up at it with the naked eye, 42 00:03:24,533 --> 00:03:28,400 we are still filled with the same awe and wonder 43 00:03:28,500 --> 00:03:30,866 they must have felt hundreds... 44 00:03:30,966 --> 00:03:32,666 Even thousands of years ago. 45 00:03:40,533 --> 00:03:42,933 For our ancestors, there was no separation 46 00:03:43,033 --> 00:03:44,533 between earth and sky. 47 00:03:49,533 --> 00:03:52,500 Together, they formed a cosmos that we shared 48 00:03:52,600 --> 00:03:55,000 with the supernatural beings that we believed 49 00:03:55,100 --> 00:03:57,166 were an integral part of its working. 50 00:04:01,533 --> 00:04:04,700 Mythology and religion are almost essential ways 51 00:04:04,800 --> 00:04:07,033 of explaining the cosmos. 52 00:04:08,600 --> 00:04:11,666 In ancient Egypt, the sky was personified 53 00:04:11,766 --> 00:04:13,500 by the goddess nut, 54 00:04:13,600 --> 00:04:16,433 who curved her body of stars over the earth. 55 00:04:19,833 --> 00:04:24,333 And the moon was associated with the gods Thoth and Khonsu. 56 00:04:27,266 --> 00:04:31,666 These supernatural beings also inhabited the stories we told 57 00:04:31,766 --> 00:04:34,366 about how the universe itself came to be. 58 00:04:36,300 --> 00:04:38,866 We explain things we can't understand 59 00:04:38,966 --> 00:04:40,300 through using stories, 60 00:04:40,400 --> 00:04:44,200 because none of us really can comprehend 61 00:04:44,300 --> 00:04:45,966 how the universe started. 62 00:04:52,333 --> 00:04:55,366 There are stories to explain the origin of the cosmos 63 00:04:55,466 --> 00:04:57,200 from all over the world. 64 00:05:00,700 --> 00:05:03,033 For the Aztecs of central America, 65 00:05:03,133 --> 00:05:05,833 it was the goddess Coatlicue who gave birth 66 00:05:05,933 --> 00:05:07,700 to the moon and stars. 67 00:05:10,366 --> 00:05:14,233 For Hindus, the god Brahma sat atop a lotus flower 68 00:05:14,333 --> 00:05:17,500 as he created the earth, the sky, and the heavens. 69 00:05:20,233 --> 00:05:23,933 And in Chinese mythology, a hairy beast called Pangu 70 00:05:24,033 --> 00:05:26,533 emerged from a cosmic egg and divided 71 00:05:26,633 --> 00:05:30,566 the forces of yin and Yang into earth and sky. 72 00:05:35,300 --> 00:05:38,000 But our earliest surviving creation myth 73 00:05:38,100 --> 00:05:42,300 dates back almost 4,000 years, to the ancient Babylonians. 74 00:05:45,166 --> 00:05:47,600 It's called the Enuma Elis. 75 00:05:54,566 --> 00:05:58,333 The Enuma Elis tells the story of a colossal battle 76 00:05:58,433 --> 00:06:01,800 between Tiamat, the primordial goddess of the sea, 77 00:06:01,900 --> 00:06:03,733 and the god Marduk. 78 00:06:07,700 --> 00:06:11,100 Marduk is described in extraordinary terms. 79 00:06:11,200 --> 00:06:15,300 He's got fourfold vision, he's got the aura of 10 gods, 80 00:06:15,400 --> 00:06:19,133 he's unfathomable and unvisualizable 81 00:06:19,233 --> 00:06:20,333 in his splendor. 82 00:06:25,533 --> 00:06:27,433 Marduk took up the mace... 83 00:06:29,133 --> 00:06:30,800 And held it in his right hand. 84 00:07:01,633 --> 00:07:04,666 Tiamat and Marduk drew close for battle... 85 00:07:08,666 --> 00:07:10,800 And locked in combat. 86 00:07:13,333 --> 00:07:16,066 Tiamat opened her jaws... 87 00:07:17,900 --> 00:07:20,300 But with his merciless mace... 88 00:07:23,133 --> 00:07:25,366 Marduk crushed her skull. 89 00:07:31,766 --> 00:07:34,366 The battle between Marduk and Tiamat 90 00:07:34,466 --> 00:07:37,366 explained the creation of the earth and ocean, 91 00:07:37,466 --> 00:07:39,833 the sky and everything in it. 92 00:07:43,833 --> 00:07:45,433 It divides the universe into 93 00:07:45,533 --> 00:07:46,966 a top and a bottom. 94 00:07:47,066 --> 00:07:51,233 We have the sky and the earth, and as part of the epic, 95 00:07:51,333 --> 00:07:53,566 and as part of Marduk's role in it, 96 00:07:53,666 --> 00:07:56,700 he creates the stars and the constellations. 97 00:08:00,100 --> 00:08:02,633 He fills the sky with all the things 98 00:08:02,733 --> 00:08:04,233 that are observed in it. 99 00:08:09,100 --> 00:08:12,366 Today, we can still get a glimpse of the cosmos 100 00:08:12,466 --> 00:08:14,066 as the Babylonians saw it... 101 00:08:18,766 --> 00:08:22,066 From the oldest world map ever discovered. 102 00:08:24,966 --> 00:08:28,833 Etched in Clay over 2,500 years ago, 103 00:08:28,933 --> 00:08:31,266 it shows the earth as a flat disc, 104 00:08:31,366 --> 00:08:32,433 floating on the ocean. 105 00:08:44,433 --> 00:08:46,533 The Babylonians imagined their flat earth 106 00:08:46,633 --> 00:08:48,566 at the center of the universe, 107 00:08:48,666 --> 00:08:51,533 with everything in the skies revolving around it. 108 00:09:01,100 --> 00:09:04,442 - Belief in a flat earth was common to many civilizations - belief in a flat earth was common to many civilizations 109 00:09:04,466 --> 00:09:05,666 Across the world... 110 00:09:10,000 --> 00:09:11,666 From the far east of Asia... 111 00:09:14,600 --> 00:09:15,900 To Africa... 112 00:09:18,000 --> 00:09:19,400 And the Americas. 113 00:09:22,833 --> 00:09:26,066 From the point of view of our ancient ancestors, 114 00:09:26,166 --> 00:09:28,466 a flat earth made perfect sense. 115 00:09:30,966 --> 00:09:32,466 We know that the earth is a ball 116 00:09:32,566 --> 00:09:34,300 and it's spinning once a day. 117 00:09:34,400 --> 00:09:36,600 But the thing is that's not obvious. 118 00:09:36,700 --> 00:09:38,733 If you go out without really thinking about that 119 00:09:38,833 --> 00:09:40,900 and just look at these motions, 120 00:09:41,000 --> 00:09:43,466 it feels like the earth is flat 121 00:09:43,566 --> 00:09:47,033 and it feels like the sky is wheeling around you. 122 00:09:50,233 --> 00:09:52,200 We can imagine that the skies must have been 123 00:09:52,300 --> 00:09:54,700 an endless source of wonder and mystery. 124 00:09:58,133 --> 00:10:00,933 A place to be admired and interpreted. 125 00:10:04,066 --> 00:10:08,133 And no matter how far back we go in our human story, 126 00:10:08,233 --> 00:10:11,533 we find evidence of our obsession with the heavens. 127 00:10:16,866 --> 00:10:20,133 Nestled deep within the hills of northern Spain 128 00:10:20,233 --> 00:10:22,233 are the caves of El Castillo. 129 00:10:27,933 --> 00:10:30,066 Here, over millennia, 130 00:10:30,166 --> 00:10:32,200 stone age artists decorated the walls 131 00:10:32,300 --> 00:10:34,200 with hundreds of paintings. 132 00:10:36,866 --> 00:10:39,933 Dr. Jesus Gallego is an astrophysicist, 133 00:10:40,033 --> 00:10:43,233 but he has spent years studying the images 134 00:10:43,333 --> 00:10:45,900 that line the walls of these caves. 135 00:10:47,333 --> 00:10:51,700 Some of them are as old as 40,000 years. 136 00:10:56,066 --> 00:10:59,666 If this is correct, we will be right now 137 00:10:59,766 --> 00:11:03,700 in front of the oldest paintings of the world. 138 00:11:06,133 --> 00:11:10,166 I am surrounded by about 30 hands. 139 00:11:10,266 --> 00:11:12,633 We estimate that 20 belong to women 140 00:11:12,733 --> 00:11:14,300 and 10 belong to men. 141 00:11:17,533 --> 00:11:20,866 I love to consider the possibility of these people 142 00:11:20,966 --> 00:11:23,933 just leaving the contour of their hands... 143 00:11:27,366 --> 00:11:31,433 To leave something for us, the people of the future. 144 00:11:35,533 --> 00:11:36,933 Dr. Gallego believes that 145 00:11:37,033 --> 00:11:39,200 whoever painted these pictures 146 00:11:39,300 --> 00:11:43,166 recorded the things that were most important to them. 147 00:11:43,266 --> 00:11:46,133 Our ancestors were people that were living 148 00:11:46,233 --> 00:11:47,833 very close to nature. 149 00:11:47,933 --> 00:11:54,600 So, it's not a surprise that these people reproduced animals 150 00:11:54,700 --> 00:11:56,933 on the walls of the caves. 151 00:11:59,866 --> 00:12:02,500 Hidden away in one corner of El Castillo 152 00:12:02,600 --> 00:12:05,442 - are a set of paintings that, as an astrophysicist, - are a set of paintings that, as an astrophysicist, 153 00:12:05,466 --> 00:12:08,800 Dr. Gallego finds particularly intriguing. 154 00:12:08,900 --> 00:12:11,633 Some people believe that here we have 155 00:12:11,733 --> 00:12:15,500 a representation of an astronomical motif 156 00:12:15,600 --> 00:12:19,633 which is very important, which is the milky way, 157 00:12:19,733 --> 00:12:23,333 a sequence of faint stars all together 158 00:12:23,433 --> 00:12:25,333 and making one single body. 159 00:12:28,133 --> 00:12:30,600 Other paintings here could also have 160 00:12:30,700 --> 00:12:33,100 an astronomical association. 161 00:12:33,200 --> 00:12:37,500 Some of the current researchers identify here 162 00:12:37,600 --> 00:12:41,666 a sequence of astronomical events 163 00:12:41,766 --> 00:12:45,066 that could be related with moon phases, 164 00:12:45,166 --> 00:12:48,800 with different days of the month. 165 00:12:48,900 --> 00:12:54,000 This is one of the best links that we can find in the cave 166 00:12:54,100 --> 00:12:56,533 related with astronomical phenomena. 167 00:12:59,733 --> 00:13:02,600 These are the earliest paintings yet discovered 168 00:13:02,700 --> 00:13:04,900 that could depict the heavens. 169 00:13:14,966 --> 00:13:17,300 In times when we relied on the natural world 170 00:13:17,400 --> 00:13:18,500 for our survival... 171 00:13:20,533 --> 00:13:23,933 Reading the skies could give our ancestors the edge. 172 00:13:27,666 --> 00:13:29,600 If you go out under the night sky every night 173 00:13:29,700 --> 00:13:31,800 and look around, you eventually become familiar 174 00:13:31,900 --> 00:13:33,233 with the patterns in the sky, 175 00:13:33,333 --> 00:13:34,813 just like you do in your neighborhood. 176 00:13:37,300 --> 00:13:39,466 You know where the trees are, where the bank is, 177 00:13:39,566 --> 00:13:43,666 where the mountains are, and this is even more true 178 00:13:43,766 --> 00:13:46,300 for our ancestors, for ancient peoples. 179 00:13:46,400 --> 00:13:49,466 They were familiar with those stars. 180 00:13:49,566 --> 00:13:51,833 That was their neighborhood. 181 00:13:58,433 --> 00:14:00,733 Our ancestors would have seen the sun 182 00:14:00,833 --> 00:14:04,433 rising and setting in the same directions every day... 183 00:14:07,733 --> 00:14:11,300 And used the positions of sunrise and sunset 184 00:14:11,400 --> 00:14:12,833 to orient themselves. 185 00:14:15,566 --> 00:14:17,700 But even when the sun went down, 186 00:14:17,800 --> 00:14:20,866 the stars still helped us find our way. 187 00:14:23,466 --> 00:14:25,433 When we look up at the sky, all the stars 188 00:14:25,533 --> 00:14:27,033 appear to be circling. 189 00:14:27,133 --> 00:14:31,233 They're wheeling around a point fixed on the sky itself. 190 00:14:35,766 --> 00:14:37,966 We call those the celestial Poles... 191 00:14:38,066 --> 00:14:39,966 The north and south celestial Poles. 192 00:14:40,066 --> 00:14:43,900 And all the stars appear to move around them. 193 00:14:44,000 --> 00:14:47,200 By locating these fixed points in the night sky, 194 00:14:47,300 --> 00:14:49,633 our ancestors could find their bearings. 195 00:14:52,166 --> 00:14:54,633 But the regular motion of the heavens 196 00:14:54,733 --> 00:14:58,800 also made us conscious of something completely fundamental 197 00:14:58,900 --> 00:15:03,300 to how we organize our lives... time. 198 00:15:04,500 --> 00:15:06,866 There are 3 basic cycles in astronomy 199 00:15:06,966 --> 00:15:08,666 if you're outside looking up at the sky 200 00:15:08,766 --> 00:15:09,933 with your naked eye. 201 00:15:11,300 --> 00:15:14,800 One of them is the day-night cycle... 24 hours. 202 00:15:19,533 --> 00:15:21,033 The next one is how long it takes 203 00:15:21,133 --> 00:15:22,800 the moon to go around the earth. 204 00:15:28,000 --> 00:15:31,600 It goes through a cycle of phases from new to half full 205 00:15:31,700 --> 00:15:35,033 to full to half full again and back to new. 206 00:15:35,133 --> 00:15:36,809 So, that gives you a way of measuring something 207 00:15:36,833 --> 00:15:38,300 like one month of time. 208 00:15:40,700 --> 00:15:42,800 There's evidence that we were counting time 209 00:15:42,900 --> 00:15:47,833 using the lunar cycle at least 34,000 years ago 210 00:15:47,933 --> 00:15:52,000 from carvings on bones discovered in Africa 211 00:15:52,100 --> 00:15:54,633 and a series of circles and crescents 212 00:15:54,733 --> 00:15:57,133 etched into an antler found in Europe 213 00:15:57,233 --> 00:16:00,433 that are believed to show the phases of the moon. 214 00:16:04,766 --> 00:16:06,309 The third one is how long it takes the earth 215 00:16:06,333 --> 00:16:08,433 to go around the sun, and that's a year. 216 00:16:10,533 --> 00:16:12,766 Using the sun, we established 217 00:16:12,866 --> 00:16:16,366 a solar year of 365 days 218 00:16:16,466 --> 00:16:18,900 that encompassed the changing seasons. 219 00:16:20,833 --> 00:16:22,533 If you set up a distant landmark 220 00:16:22,633 --> 00:16:24,500 and line yourself up with the sun at, say, 221 00:16:24,600 --> 00:16:28,733 the mid-winter solstice, when the sun crosses 222 00:16:28,833 --> 00:16:31,600 the horizon behind there, you Mark that day. 223 00:16:33,800 --> 00:16:35,809 Then, when the sun crosses the horizon the next day, 224 00:16:35,833 --> 00:16:37,142 it's a little bit off and a little bit more 225 00:16:37,166 --> 00:16:38,633 and a little bit more day after day. 226 00:16:39,833 --> 00:16:41,100 Then it starts to move back 227 00:16:41,200 --> 00:16:42,466 over the course of the year... 228 00:16:44,500 --> 00:16:45,766 And right when it rises 229 00:16:45,866 --> 00:16:50,900 behind that landmark again... Boom! 230 00:16:51,000 --> 00:16:52,700 You know you've been waiting one year. 231 00:16:55,800 --> 00:16:59,100 All over the world, some of the oldest monuments 232 00:16:59,200 --> 00:17:01,466 created by human hands were built 233 00:17:01,566 --> 00:17:03,100 to track the solar year. 234 00:17:07,666 --> 00:17:10,866 The earliest examples are markers on the landscape. 235 00:17:13,033 --> 00:17:17,133 Like Wurdi Youang, erected by aboriginal peoples in Australia 236 00:17:17,233 --> 00:17:19,333 up to 11,000 years ago. 237 00:17:22,933 --> 00:17:24,733 A series of pits dug in the ground 238 00:17:24,833 --> 00:17:28,166 at Warren field in Scotland, 10,000 years ago. 239 00:17:32,766 --> 00:17:34,933 And the 7,000-year-old stone circle 240 00:17:35,033 --> 00:17:36,933 of Nabta playa in Egypt. 241 00:17:51,933 --> 00:17:55,133 Over centuries, these simple markers 242 00:17:55,233 --> 00:17:57,233 could become colossal structures... 243 00:17:59,466 --> 00:18:02,133 Some of which have survived to the present day. 244 00:18:06,966 --> 00:18:10,266 Stonehenge is perched at the top of Salisbury plain 245 00:18:10,366 --> 00:18:11,800 in the south of England. 246 00:18:11,900 --> 00:18:14,800 It is one of the most famous monuments on the planet. 247 00:18:19,233 --> 00:18:24,233 Building this monument 5,000 years ago was a herculean task. 248 00:18:24,333 --> 00:18:26,366 The largest stones at Stonehenge 249 00:18:26,466 --> 00:18:28,600 are up to 30 feet long 250 00:18:28,700 --> 00:18:32,233 and weigh up to 50 tons. 251 00:18:32,333 --> 00:18:34,866 Some of them were brought by ancient Britons 252 00:18:34,966 --> 00:18:40,300 from the Preseli hills in wales, 150 miles away. 253 00:18:40,400 --> 00:18:42,466 Nobody needed to transport those stones. 254 00:18:42,566 --> 00:18:46,866 They did so because those stones had some vital quality 255 00:18:46,966 --> 00:18:49,166 that was needed at Stonehenge. 256 00:18:49,266 --> 00:18:54,433 These are fantastically complex exercises. 257 00:18:54,533 --> 00:18:57,333 The effort required to build Stonehenge 258 00:18:57,433 --> 00:19:01,066 shows just how important it was. 259 00:19:01,166 --> 00:19:03,933 People were investing vast resources to create 260 00:19:04,033 --> 00:19:08,433 a centralized gathering place for the entire island. 261 00:19:08,533 --> 00:19:10,500 Stonehenge was a feast site 262 00:19:10,600 --> 00:19:12,833 for possibly the whole of Britain. 263 00:19:15,633 --> 00:19:17,766 People would know a year in advance 264 00:19:17,866 --> 00:19:20,200 when the feast was going to be. 265 00:19:20,300 --> 00:19:24,033 But this wasn't just a place to come and feast. 266 00:19:24,133 --> 00:19:26,766 People traveled vast distances to carry out 267 00:19:26,866 --> 00:19:28,633 ritual activities here. 268 00:19:31,100 --> 00:19:35,266 It seems this was a place to worship the sun. 269 00:19:35,366 --> 00:19:37,600 There would have been all sorts of rituals there 270 00:19:37,700 --> 00:19:41,066 to encourage the power of the sun 271 00:19:41,166 --> 00:19:45,000 to return life to the land in the middle of the winter. 272 00:19:47,066 --> 00:19:48,700 Stonehenge is aligned to Mark 273 00:19:48,800 --> 00:19:51,466 sunrise on the summer solstice 274 00:19:51,566 --> 00:19:54,100 and sunset on the winter solstice. 275 00:19:57,733 --> 00:20:00,533 A kind of giant solar calendar 276 00:20:00,633 --> 00:20:03,833 to Mark the longest and shortest days of the year. 277 00:20:05,866 --> 00:20:09,433 This connection between religion and solar alignment 278 00:20:09,533 --> 00:20:12,100 can be seen across the world. 279 00:20:23,233 --> 00:20:26,033 The great pyramid of Giza is the only remaining 280 00:20:26,133 --> 00:20:27,733 wonder of the ancient world. 281 00:20:33,766 --> 00:20:37,233 It is located on the banks of the Nile in Egypt. 282 00:20:39,900 --> 00:20:43,933 The great pyramid was built over 4,500 years ago 283 00:20:44,033 --> 00:20:47,733 as a tomb for the ancient Egyptian pharaoh Khufu. 284 00:20:49,666 --> 00:20:51,700 It is the centerpiece of a complex 285 00:20:51,800 --> 00:20:56,666 containing 3 giant pyramids. 286 00:20:56,766 --> 00:21:00,466 And the people who built these pyramids took great care 287 00:21:00,566 --> 00:21:02,966 in making sure that they were aligned 288 00:21:03,066 --> 00:21:05,226 - to the 4 cardinal points. - To the 4 cardinal points. 289 00:21:07,733 --> 00:21:10,100 When we look at the pyramids today, 290 00:21:10,200 --> 00:21:12,533 we can see very clearly that they are aligned 291 00:21:12,633 --> 00:21:18,000 precisely towards true north, so, north, east, south, and west 292 00:21:18,100 --> 00:21:21,766 are almost exactly correctly referenced. 293 00:21:23,933 --> 00:21:27,233 The ancient Egyptians' calculations were so exact 294 00:21:27,333 --> 00:21:30,233 that the pyramids are aligned with the points of the compass 295 00:21:30,333 --> 00:21:32,766 to within 1/15th of a degree. 296 00:21:36,066 --> 00:21:38,566 The fact that the ancient Egyptians took such pains 297 00:21:38,666 --> 00:21:41,200 to align the pyramids so accurately 298 00:21:41,300 --> 00:21:44,433 suggests there must have been a greater meaning. 299 00:21:46,233 --> 00:21:48,566 We know at the time of the great pyramids 300 00:21:48,666 --> 00:21:53,833 that there is an increased interest in the sun. 301 00:21:53,933 --> 00:21:58,600 That's made quite explicit in the titles of the pharaohs. 302 00:21:58,700 --> 00:22:00,466 For the first time, the pharaoh is described 303 00:22:00,566 --> 00:22:03,133 as the son of Ra the sun god. 304 00:22:04,766 --> 00:22:08,366 So, it's interesting that the relevance of solar alignment 305 00:22:08,466 --> 00:22:11,300 could be tied in directly to the importance of the king 306 00:22:11,400 --> 00:22:13,366 as the child of the sun. 307 00:22:13,466 --> 00:22:16,133 In the world of ancient Egyptian religion, 308 00:22:16,233 --> 00:22:19,533 the sun was embodied by the god Ra. 309 00:22:21,833 --> 00:22:24,466 The Egyptians imagined him in a boat 310 00:22:24,566 --> 00:22:26,966 that he sailed across the sky each day. 311 00:22:29,366 --> 00:22:31,866 And they also told stories that explained 312 00:22:31,966 --> 00:22:35,500 where he went when the sun set. 313 00:22:35,600 --> 00:22:39,466 In Egyptian religion, Ra dies every night, 314 00:22:39,566 --> 00:22:42,833 and he goes through a nocturnal journey into the underworld. 315 00:22:44,633 --> 00:22:47,933 One of the functions of the Egyptian priesthood 316 00:22:48,033 --> 00:22:50,900 was to prepare for and celebrate 317 00:22:51,000 --> 00:22:54,033 the rebirth of Ra the sun at dawn. 318 00:22:57,400 --> 00:22:59,600 Ra's importance to the ancient Egyptians 319 00:22:59,700 --> 00:23:01,866 can be seen in the celestial alignment 320 00:23:01,966 --> 00:23:03,300 of the pyramids of Giza. 321 00:23:06,833 --> 00:23:09,433 But how did builders achieve such an astonishing 322 00:23:09,533 --> 00:23:14,100 level of accuracy over 4,500 years ago? 323 00:23:15,600 --> 00:23:17,400 It's easy to think that ancient people 324 00:23:17,500 --> 00:23:19,533 didn't really know how to do any of the stuff 325 00:23:19,633 --> 00:23:22,200 but, in fact, they understood the way the sun moved, 326 00:23:22,300 --> 00:23:24,266 they understood the way the shadows moved. 327 00:23:26,666 --> 00:23:30,600 They had the knowledge of astronomy and geometry and engineering 328 00:23:30,700 --> 00:23:33,233 that was fine for doing this sort of thing. 329 00:23:33,333 --> 00:23:34,893 They were able to find the directions of 330 00:23:34,933 --> 00:23:38,466 north, south, east, and west pretty accurately. 331 00:23:38,566 --> 00:23:43,266 And all you need is a long stick, 332 00:23:43,366 --> 00:23:45,966 a plum Bob, and a hammer. 333 00:23:48,166 --> 00:23:50,433 This long stick is called a gnomon, 334 00:23:50,533 --> 00:23:51,576 and if you stick it in the ground 335 00:23:51,600 --> 00:23:52,966 straight up and down, 336 00:23:53,066 --> 00:23:55,666 it will cast a shadow due to the sunlight. 337 00:23:55,766 --> 00:23:57,000 Yeah, that's not bad. 338 00:23:59,900 --> 00:24:01,633 Now that we have our gnomon in the ground 339 00:24:01,733 --> 00:24:03,366 and it's straight up and down, 340 00:24:03,466 --> 00:24:05,133 it's casting a shadow due to sunlight. 341 00:24:05,134 --> 00:24:06,800 It's casting a shadow due to sunlight. 342 00:24:06,900 --> 00:24:09,133 Now all we have to do is Mark the end of that shadow 343 00:24:09,233 --> 00:24:11,333 several times over the course of the day. 344 00:24:11,433 --> 00:24:13,066 That's going to make an arc on the ground 345 00:24:13,166 --> 00:24:15,500 as the sun rises and sets, 346 00:24:15,600 --> 00:24:18,066 and that's what's going to help me find east and west. 347 00:24:24,833 --> 00:24:26,500 Once we have the arc in the ground 348 00:24:26,600 --> 00:24:28,040 representing the length of the shadow 349 00:24:28,066 --> 00:24:30,566 over the course of the day, 350 00:24:30,666 --> 00:24:33,733 we can take a piece of string and tie it to this gnomon, 351 00:24:33,833 --> 00:24:36,000 move out a certain distance, and then just use that 352 00:24:36,100 --> 00:24:37,666 to draw a circle in the ground. 353 00:24:39,900 --> 00:24:43,066 That circle will intersect the arc in two spots, 354 00:24:43,166 --> 00:24:46,100 draw a line connecting those two points. 355 00:24:46,200 --> 00:24:47,800 That points east and west. 356 00:24:51,433 --> 00:24:54,133 Experts believe this is how the ancient Egyptians 357 00:24:54,233 --> 00:24:56,733 used the sun to align the pyramids of Giza 358 00:24:56,833 --> 00:24:59,666 to north, south, east, and west. 359 00:25:13,933 --> 00:25:16,533 Across the world, every civilization that was 360 00:25:16,633 --> 00:25:19,100 moved to build major religious monuments 361 00:25:19,200 --> 00:25:21,933 made them with celestial alignments. 362 00:25:24,500 --> 00:25:27,933 The Aztecs tended to orient their main temple 363 00:25:28,033 --> 00:25:29,800 to the east facing west, 364 00:25:29,900 --> 00:25:32,700 especially for Tenochtitlan's great temple. 365 00:25:32,800 --> 00:25:36,100 The two shrines on top of it were aligned 366 00:25:36,200 --> 00:25:38,166 so that on the equinox, the sun would rise 367 00:25:38,266 --> 00:25:39,700 directly between them. 368 00:25:41,233 --> 00:25:44,133 We can see other similarly aligned monuments 369 00:25:44,233 --> 00:25:48,366 on that east-west, north-south model in India... 370 00:25:53,166 --> 00:25:54,633 Southeast Asia, 371 00:25:54,733 --> 00:26:01,333 in Cambodia, the great temples of Angkor, huge site. 372 00:26:08,766 --> 00:26:11,100 These were civilizations separated by 373 00:26:11,200 --> 00:26:15,033 thousands of miles and centuries in time, 374 00:26:15,133 --> 00:26:17,933 that evolved completely independently of one another. 375 00:26:25,233 --> 00:26:27,900 And yet, they were all using astronomy 376 00:26:28,000 --> 00:26:30,633 to build celestially aligned monuments... 377 00:26:33,366 --> 00:26:34,433 To navigate... 378 00:26:37,266 --> 00:26:39,033 And even tell the time. 379 00:26:41,200 --> 00:26:44,666 But astronomy didn't just influence our architecture. 380 00:26:44,766 --> 00:26:49,733 It also inspired us to create treasures of exquisite beauty. 381 00:26:51,733 --> 00:26:55,833 At the Halle state museum of prehistory in eastern Germany, 382 00:26:55,933 --> 00:26:57,866 there's an artifact that could be 383 00:26:57,966 --> 00:27:01,700 our earliest astronomical instrument. 384 00:27:01,800 --> 00:27:03,750 It is known as the Nebra sky disc. 385 00:27:03,751 --> 00:27:05,700 It is known as the Nebra sky disc. 386 00:27:05,800 --> 00:27:08,966 Discovered in 1999, it is believed to have been made 387 00:27:09,066 --> 00:27:15,066 over 3,500 years ago in the heart of bronze age Europe. 388 00:27:15,166 --> 00:27:18,200 Made from bronze overlaid with gold, 389 00:27:18,300 --> 00:27:20,100 the disc has been interpreted to show 390 00:27:20,200 --> 00:27:23,600 a variety of objects in the night sky. 391 00:27:23,700 --> 00:27:27,400 It now sits permanently behind glass. 392 00:27:27,500 --> 00:27:31,633 But Dr. Harald Meller has used this precious, perfect copy 393 00:27:31,733 --> 00:27:34,333 to study its secrets. 394 00:27:59,666 --> 00:28:02,166 By lining up these horizon arcs with the sunrise 395 00:28:02,266 --> 00:28:04,266 on specific days of the year, 396 00:28:04,366 --> 00:28:07,266 it could be used as a kind of solar calendar. 397 00:28:49,900 --> 00:28:51,566 The Nebra sky disc shows how 398 00:28:51,666 --> 00:28:54,000 a culture without writing could use pictures 399 00:28:54,100 --> 00:28:56,266 to record astronomical observations. 400 00:28:59,133 --> 00:29:03,533 But 2,000 miles away, one of our greatest civilizations 401 00:29:03,633 --> 00:29:06,766 would use the written word to take astronomy 402 00:29:06,866 --> 00:29:09,666 to a whole new level. 403 00:29:13,166 --> 00:29:16,266 It all began in a place often referred to 404 00:29:16,366 --> 00:29:18,500 as the cradle of civilization... 405 00:29:20,933 --> 00:29:22,166 Ancient Mesopotamia. 406 00:29:30,066 --> 00:29:31,766 When we talk about ancient Mesopotamia, 407 00:29:31,866 --> 00:29:33,833 we are referring to a geographical region 408 00:29:33,933 --> 00:29:35,366 that is currently covered by 409 00:29:35,466 --> 00:29:37,700 Iraq, Syria, and parts of Turkey. 410 00:29:37,800 --> 00:29:42,500 It's the region that is around the Tigris and Euphrates rivers. 411 00:29:43,900 --> 00:29:46,366 And that's actually where the name comes from. 412 00:29:46,466 --> 00:29:49,866 Mesopotamia is Greek for "the land between rivers." 413 00:29:54,233 --> 00:29:56,766 Within the region of ancient Mesopotamia 414 00:29:56,866 --> 00:29:58,933 was the famous city of Babylon. 415 00:30:01,833 --> 00:30:05,276 - It was the Babylonians who gave us our earliest known - it was the Babylonians who gave us our earliest known 416 00:30:05,300 --> 00:30:08,066 Scientific observations of the skies, 417 00:30:08,166 --> 00:30:11,866 starting over 3,000 years ago. 418 00:30:11,966 --> 00:30:13,833 They were the first to systematically record 419 00:30:13,933 --> 00:30:17,866 observations about the planets and the stars, 420 00:30:17,966 --> 00:30:20,666 about the motion of celestial bodies, 421 00:30:20,766 --> 00:30:25,700 and to try to correlate them to more familiar events 422 00:30:25,800 --> 00:30:28,033 that happened in the human sphere. 423 00:30:30,966 --> 00:30:32,000 Many of these recordings 424 00:30:32,100 --> 00:30:33,766 have survived to this day. 425 00:30:35,666 --> 00:30:38,766 They are kept here, at the British museum in London. 426 00:30:48,166 --> 00:30:51,866 They are written in cuneiform, an ancient form of writing 427 00:30:51,966 --> 00:30:54,766 that dominated in this part of the world for centuries. 428 00:31:02,633 --> 00:31:04,566 Cuneiform is a system of writing 429 00:31:04,666 --> 00:31:07,000 predominantly on Clay using a wedge-shaped stylus 430 00:31:07,100 --> 00:31:09,766 to produce wedge-shaped signs, 431 00:31:09,866 --> 00:31:11,500 and these signs can make up words. 432 00:31:12,933 --> 00:31:15,633 Hundreds of thousands of cuneiform texts 433 00:31:15,733 --> 00:31:18,100 have been found by archaeologists. 434 00:31:18,200 --> 00:31:22,200 But the knowledge to decode them is relatively recent. 435 00:31:22,300 --> 00:31:25,466 Even today, there are very few people in the world 436 00:31:25,566 --> 00:31:26,600 who can read them. 437 00:31:28,033 --> 00:31:31,833 Professor John Steele is one of these few. 438 00:31:31,933 --> 00:31:33,176 The Babylonians were the first to really get 439 00:31:33,200 --> 00:31:35,300 interested in making detailed, precise, 440 00:31:35,400 --> 00:31:37,500 and regular observations. 441 00:31:37,600 --> 00:31:39,733 They were looking for eclipses. 442 00:31:39,833 --> 00:31:42,900 They were looking for the motion of the moon past stars, 443 00:31:43,000 --> 00:31:45,400 the motion of the planets past stars. 444 00:31:45,500 --> 00:31:47,900 This a very interesting collection 445 00:31:48,000 --> 00:31:50,033 of lunar eclipse observations. 446 00:31:50,133 --> 00:31:53,000 The compilation extends for over 400 years 447 00:31:53,100 --> 00:31:54,476 from the middle of the eighth century 448 00:31:54,500 --> 00:31:56,800 down to just before 300 B.C., 449 00:31:56,900 --> 00:31:58,900 and you can see here it's divided up 450 00:31:59,000 --> 00:32:01,333 into a grid like a table, like a modern spreadsheet, 451 00:32:01,433 --> 00:32:03,333 and within each cell of the table, 452 00:32:03,433 --> 00:32:06,100 we have a report of a lunar eclipse. 453 00:32:08,366 --> 00:32:10,066 These records were added to 454 00:32:10,166 --> 00:32:12,133 from generation to generation... 455 00:32:16,066 --> 00:32:20,066 Enabling Babylonian astronomers to look at patterns and cycles 456 00:32:20,166 --> 00:32:22,266 in the skies over centuries. 457 00:32:24,600 --> 00:32:26,542 As a consequence of that, they were the first people 458 00:32:26,566 --> 00:32:29,200 to attempt to analyze these things mathematically, 459 00:32:29,300 --> 00:32:32,333 to make precise and detailed and accurate predictions. 460 00:32:34,333 --> 00:32:37,733 Contained in these tablets is the very birth 461 00:32:37,833 --> 00:32:39,866 of modern astronomy. 462 00:32:39,966 --> 00:32:42,133 So, really, on both the observational 463 00:32:42,233 --> 00:32:44,900 and the predictive or theoretical side, Babylon is 464 00:32:45,000 --> 00:32:46,833 where it all starts across the world. 465 00:32:52,400 --> 00:32:55,300 The Babylonians believed that by using astronomy 466 00:32:55,400 --> 00:32:57,200 to understand the skies, 467 00:32:57,300 --> 00:33:00,233 they could interpret the desires of the gods. 468 00:33:02,100 --> 00:33:05,409 - The celestial bodies, whether they were stars or planets, - The celestial bodies, whether they were stars or planets, 469 00:33:05,433 --> 00:33:08,066 Were thought to be the writing of the gods, 470 00:33:08,166 --> 00:33:11,766 and the sky was understood as a kind of stone tablet 471 00:33:11,866 --> 00:33:14,666 on which the gods inscribed their messages. 472 00:33:16,500 --> 00:33:19,300 If they could read these divine messages, 473 00:33:19,400 --> 00:33:21,600 the Babylonians could take appropriate action 474 00:33:21,700 --> 00:33:22,833 in the mortal realm. 475 00:33:28,933 --> 00:33:30,166 An eclipse, for example, 476 00:33:30,266 --> 00:33:32,266 was a very dangerous phenomenon 477 00:33:32,366 --> 00:33:34,566 that required the king to be hidden away 478 00:33:34,666 --> 00:33:36,966 and a substitute put in his place for a few months 479 00:33:37,066 --> 00:33:39,300 until the danger was perceived to have passed. 480 00:33:41,166 --> 00:33:42,666 This need to look to the skies 481 00:33:42,766 --> 00:33:45,100 for help in making important decisions 482 00:33:45,200 --> 00:33:47,566 can be seen all over the world. 483 00:33:54,433 --> 00:33:58,566 In central America, another of our great civilizations became 484 00:33:58,666 --> 00:34:03,533 skilled astronomers to better understand the will of the gods. 485 00:34:05,633 --> 00:34:08,533 We can pick up traces of Maya culture 486 00:34:08,633 --> 00:34:11,166 going back to the second millennium BCE. 487 00:34:16,200 --> 00:34:19,266 The Mayas created the most sophisticated writing system 488 00:34:19,366 --> 00:34:21,066 of the pre-columbian Americas. 489 00:34:22,900 --> 00:34:24,166 They wrote on their pottery. 490 00:34:26,633 --> 00:34:28,900 They wrote in sculpted hieroglyphs 491 00:34:29,000 --> 00:34:31,300 on monuments and on stairways. 492 00:34:35,933 --> 00:34:38,266 These inscriptions survive on Mayan documents 493 00:34:38,366 --> 00:34:41,400 across parts of modern-day Mexico, Guatemala, 494 00:34:41,500 --> 00:34:43,166 Belize, and Honduras. 495 00:34:46,566 --> 00:34:49,400 We also have records that the Maya wrote books 496 00:34:49,500 --> 00:34:51,666 on a paper made from the ficus tree. 497 00:34:54,400 --> 00:34:58,366 Almost all of these have been lost over time, 498 00:34:58,466 --> 00:35:00,400 whether they decomposed in the humid 499 00:35:00,500 --> 00:35:02,966 central American climate 500 00:35:03,066 --> 00:35:07,466 or were destroyed by marauding Spanish conquistadors 501 00:35:07,566 --> 00:35:09,100 in the 16th century. 502 00:35:13,033 --> 00:35:17,066 But at the Saxon state library in eastern Germany, 503 00:35:17,166 --> 00:35:21,033 locked away in a room known as the treasure chamber, 504 00:35:21,133 --> 00:35:25,700 is one of only 4 Mayan books left in the world. 505 00:35:25,800 --> 00:35:29,366 It is known as the Dresden codex. 506 00:35:29,466 --> 00:35:32,533 And archaeologist Dr. Christian Prager 507 00:35:32,633 --> 00:35:36,000 has studied it for years. 508 00:35:36,100 --> 00:35:39,866 This book here comes from the 12th or 13th century, 509 00:35:39,966 --> 00:35:42,733 but was used until the arrival of the Spaniards. 510 00:35:44,900 --> 00:35:47,400 The Dresden codex is the most complete 511 00:35:47,500 --> 00:35:51,133 of the 4 surviving books written by the Maya. 512 00:35:51,233 --> 00:35:54,500 It shows how the Mayans used the skies to influence 513 00:35:54,600 --> 00:35:56,933 decision-making in their everyday lives. 514 00:35:59,233 --> 00:36:00,833 The Dresden codex was a book 515 00:36:00,933 --> 00:36:05,042 - that was used by Maya priests to give advice to people. - That was used by Maya priests to give advice to people. 516 00:36:05,066 --> 00:36:06,933 For example, which is the best day 517 00:36:07,033 --> 00:36:09,333 to give food to a specific god 518 00:36:09,433 --> 00:36:11,966 or when is the best day to go to hunt 519 00:36:12,066 --> 00:36:15,600 and on which day will there be rain and so on. 520 00:36:20,000 --> 00:36:22,333 The codex contains a number of sections 521 00:36:22,433 --> 00:36:24,700 which relate directly to the skies 522 00:36:24,800 --> 00:36:26,933 and their religious significance. 523 00:36:32,466 --> 00:36:34,900 They believed in a lot of gods. 524 00:36:35,000 --> 00:36:38,900 And they had specific gods for the rain, for the royal power, 525 00:36:39,000 --> 00:36:41,233 for death, and so on. 526 00:36:46,233 --> 00:36:48,433 The moon goddess is the seated lady here 527 00:36:48,533 --> 00:36:50,866 with the black hair, with a figure on her back. 528 00:37:01,433 --> 00:37:03,733 This is a depiction of a sun eclipse. 529 00:37:03,833 --> 00:37:06,500 It always has a black and white area. 530 00:37:06,600 --> 00:37:09,533 And the sun eclipse is hanging from a celestial band. 531 00:37:15,466 --> 00:37:18,900 As well as providing ritual and religious information, 532 00:37:19,000 --> 00:37:21,100 it also gives us a clear window 533 00:37:21,200 --> 00:37:23,400 into the world of Mayan astronomy. 534 00:37:26,400 --> 00:37:29,233 The astronomical observations in the Dresden codex 535 00:37:29,333 --> 00:37:31,733 are very exact. 536 00:37:31,833 --> 00:37:34,600 They can be compared to our knowledge from today. 537 00:37:36,400 --> 00:37:38,466 Just like the Babylonians, 538 00:37:38,566 --> 00:37:40,466 the Maya compiled tables of 539 00:37:40,566 --> 00:37:42,900 complex astronomical observations. 540 00:37:46,200 --> 00:37:47,400 The astronomical information 541 00:37:47,500 --> 00:37:49,500 that we have in the Dresden codex 542 00:37:49,600 --> 00:37:56,466 are mainly on Venus cycles and the eclipse cycles, 543 00:37:56,566 --> 00:37:59,466 the eclipse... lunar and solar eclipse. 544 00:37:59,566 --> 00:38:01,066 This is the most important thing. 545 00:38:03,400 --> 00:38:07,866 Venus was particularly important to the Mayans. 546 00:38:07,966 --> 00:38:10,833 Its presence in the sky had the possibility 547 00:38:10,933 --> 00:38:13,700 to predict warfare. 548 00:38:13,800 --> 00:38:16,300 And by watching Venus closely, 549 00:38:16,400 --> 00:38:19,233 the Mayans were able to make a discovery about it 550 00:38:19,333 --> 00:38:21,466 that eluded other civilizations. 551 00:38:24,933 --> 00:38:26,500 One of the fascinating things about 552 00:38:26,600 --> 00:38:29,233 mesoamerican astronomers is that they figured out 553 00:38:29,333 --> 00:38:31,400 that Venus was a single entity. 554 00:38:33,133 --> 00:38:35,200 Whereas in much of the world, 555 00:38:35,300 --> 00:38:36,340 people thought that it was 556 00:38:36,400 --> 00:38:38,966 an evening star and a morning star 557 00:38:39,066 --> 00:38:41,233 and they were two separate beings, 558 00:38:41,333 --> 00:38:44,200 but mesoamericans figured out that there was a cycle 559 00:38:44,300 --> 00:38:46,866 where it returns to the same spot on the landscape. 560 00:38:51,633 --> 00:38:53,900 The calculations for the Venus cycles can be seen 561 00:38:54,000 --> 00:38:56,900 here in the dots and bars that the Mayans used 562 00:38:57,000 --> 00:38:58,333 to signify numbers. 563 00:39:00,833 --> 00:39:04,576 - They calculated the correct day when there was - They calculated the correct day when there was 564 00:39:04,600 --> 00:39:06,300 The Venus as morning star, 565 00:39:06,400 --> 00:39:08,366 when there was the Venus as evening star. 566 00:39:08,466 --> 00:39:13,500 The phase of the Venus is 583 point something days 567 00:39:13,600 --> 00:39:16,766 and they calculated 584 days. 568 00:39:16,866 --> 00:39:20,033 So, after 13 years, there is a deviation of one day. 569 00:39:20,133 --> 00:39:22,000 They corrected this one day. 570 00:39:22,100 --> 00:39:25,666 So, according to the knowledge that we have today, 571 00:39:25,766 --> 00:39:28,800 these predictions of the Venus positions 572 00:39:28,900 --> 00:39:30,366 were very exact. 573 00:39:36,800 --> 00:39:39,900 All over the world, our great civilizations 574 00:39:40,000 --> 00:39:43,633 looked at the skies and recorded the things they saw. 575 00:39:47,333 --> 00:39:50,433 The Egyptians began to draw up star clocks 576 00:39:50,533 --> 00:39:53,066 to track the motions of selected stars. 577 00:39:55,400 --> 00:39:57,800 Ancient Indian stargazers wrote texts 578 00:39:57,900 --> 00:40:00,466 detailing their observations of the skies. 579 00:40:03,500 --> 00:40:07,433 And Chinese astronomers created complex maps of the stars. 580 00:40:09,433 --> 00:40:12,366 The science of astronomy had arrived. 581 00:40:25,866 --> 00:40:29,166 All ancient astronomers needed ways to navigate 582 00:40:29,266 --> 00:40:32,300 the fantastically complex night sky. 583 00:40:35,600 --> 00:40:37,600 You go out at night and you look up in the sky 584 00:40:37,700 --> 00:40:40,533 and you see the stars, and those stars stay 585 00:40:40,633 --> 00:40:44,000 in that same fixed pattern night after night after night. 586 00:40:46,366 --> 00:40:48,566 Those patterns gave our ancient ancestors 587 00:40:48,666 --> 00:40:51,766 a way to create memorable landmarks in the sky. 588 00:40:55,800 --> 00:40:59,866 Today, we know them as constellations. 589 00:40:59,966 --> 00:41:02,200 A constellation is a group of stars, 590 00:41:02,300 --> 00:41:06,000 that's what the word means, and so, we tend to see the stars 591 00:41:06,100 --> 00:41:10,100 in these patterns when we look across the sky. 592 00:41:10,200 --> 00:41:12,833 For example, there's Ursa major, the big bear. 593 00:41:19,700 --> 00:41:21,900 Or Orion the hunter, which looks enough like 594 00:41:22,000 --> 00:41:24,233 a person with their arms raised. 595 00:41:30,700 --> 00:41:34,866 Leo the lion kind of looks like a lion seen from the side, 596 00:41:34,966 --> 00:41:37,166 and so, a lot of different cultures recognize that 597 00:41:37,266 --> 00:41:39,033 if they're familiar with lions. 598 00:41:45,000 --> 00:41:46,800 But not every culture saw 599 00:41:46,900 --> 00:41:49,000 the same shapes in the stars. 600 00:41:50,700 --> 00:41:53,566 Constellations have more to do with patterns 601 00:41:53,666 --> 00:41:56,400 that have had cultural or other types of significance 602 00:41:56,500 --> 00:41:59,400 for the various cultures and civilizations 603 00:41:59,500 --> 00:42:02,333 who have noticed these patterns throughout human history. 604 00:42:04,966 --> 00:42:08,933 Chinese astronomers saw a monkey, 605 00:42:09,033 --> 00:42:12,433 a snake, and a dragon. 606 00:42:14,900 --> 00:42:18,966 Native Americans saw a beaver, an owl, and a wolf. 607 00:42:21,833 --> 00:42:24,133 And the Aztecs saw practical things 608 00:42:24,233 --> 00:42:25,733 from their everyday lives. 609 00:42:28,200 --> 00:42:29,800 What we call the Pleiades, 610 00:42:29,900 --> 00:42:31,433 the Aztecs called Tianquiztli, 611 00:42:31,533 --> 00:42:32,933 which is the marketplace. 612 00:42:34,833 --> 00:42:37,733 Then, what we call Orion's belt and sword 613 00:42:37,833 --> 00:42:39,366 was seen as a fire drill. 614 00:42:45,033 --> 00:42:47,400 Today in the western world, there are 88 615 00:42:47,500 --> 00:42:50,600 officially recognized constellations in the night sky. 616 00:42:53,733 --> 00:42:58,366 But most of us are familiar with a much smaller number of them. 617 00:42:58,466 --> 00:43:00,866 They are the ones that have been grouped together 618 00:43:00,966 --> 00:43:03,500 into what we now call the zodiac. 619 00:43:07,800 --> 00:43:10,966 We recognize 12 official zodiac constellations. 620 00:43:11,066 --> 00:43:13,866 The ones you've heard of... Libra, Taurus, Gemini, 621 00:43:13,966 --> 00:43:15,033 and all of those. 622 00:43:18,033 --> 00:43:20,000 There is Aries, the ram... 623 00:43:22,900 --> 00:43:24,233 Virgo, the maiden... 624 00:43:26,566 --> 00:43:28,466 And cancer, the crab. 625 00:43:31,966 --> 00:43:34,966 The zodiac was established by Babylonian astronomers 626 00:43:35,066 --> 00:43:37,600 around 2,500 years ago... 627 00:43:40,233 --> 00:43:43,800 And it's the same zodiac that exists to this day. 628 00:43:46,133 --> 00:43:48,133 But picking 12 constellations 629 00:43:48,233 --> 00:43:50,333 from the countless patterns in the sky 630 00:43:50,433 --> 00:43:53,400 wasn't just a flight of fancy. 631 00:43:53,500 --> 00:43:57,266 There was a serious scientific reason behind it. 632 00:43:57,366 --> 00:43:59,100 As the earth goes around the sun 633 00:43:59,200 --> 00:44:00,633 over the course of the year, 634 00:44:00,733 --> 00:44:04,900 it appears that the sun is moving in a line around the sky. 635 00:44:05,000 --> 00:44:07,900 We call that line the ecliptic. 636 00:44:08,000 --> 00:44:10,966 And the constellations that it passes through, those 637 00:44:11,066 --> 00:44:12,933 are the zodiac constellations. 638 00:44:18,766 --> 00:44:21,166 The 12 zodiac constellations provided 639 00:44:21,266 --> 00:44:24,100 Babylonian astronomers with a virtual grid system 640 00:44:24,200 --> 00:44:25,300 in the sky. 641 00:44:28,300 --> 00:44:31,000 They used this grid to accurately identify 642 00:44:31,100 --> 00:44:33,700 the locations of all their observations. 643 00:44:35,466 --> 00:44:39,500 This enabled the Babylonians to take the science of astronomy 644 00:44:39,600 --> 00:44:41,200 to a whole new level. 645 00:44:44,300 --> 00:44:46,533 What the zodiac did was it allowed them to 646 00:44:46,633 --> 00:44:48,866 organize information in a new way. 647 00:44:48,966 --> 00:44:53,366 From about the sixth and fifth centuries B.C. Onward, 648 00:44:53,466 --> 00:44:57,333 we start to really see advanced mathematical astronomy 649 00:44:57,433 --> 00:45:02,000 being carried out by scholars, astronomers, and astrologers 650 00:45:02,100 --> 00:45:03,466 in ancient Babylonia. 651 00:45:05,066 --> 00:45:07,200 They were able to build a mathematical model 652 00:45:07,300 --> 00:45:08,600 of the cosmos 653 00:45:08,700 --> 00:45:12,866 and to predict the movements of stars and planets. 654 00:45:12,966 --> 00:45:16,000 But while their astronomy was scientific, 655 00:45:16,100 --> 00:45:18,866 their writings show that they still believed 656 00:45:18,966 --> 00:45:24,600 that everything in the skies was moved by gods and goddesses. 657 00:45:24,700 --> 00:45:25,866 The sort of systematic 658 00:45:25,966 --> 00:45:28,066 observation and extrapolation 659 00:45:28,166 --> 00:45:30,966 that we find in these texts is a kind of testament 660 00:45:31,066 --> 00:45:34,966 to the assumption that the gods were responsible 661 00:45:35,066 --> 00:45:38,033 for what we saw in the sky 662 00:45:38,133 --> 00:45:41,333 and that the divine was inseparable 663 00:45:41,433 --> 00:45:43,766 from the natural sphere. 664 00:45:43,866 --> 00:45:46,266 But the rise of a new civilization 665 00:45:46,366 --> 00:45:49,266 was about to completely revolutionize 666 00:45:49,366 --> 00:45:51,833 the way we understood the cosmos. 667 00:46:01,400 --> 00:46:04,033 Almost 3,000 years ago, the peoples of 668 00:46:04,133 --> 00:46:05,600 Greece and the Aegean sea 669 00:46:05,700 --> 00:46:07,566 were emerging from a dark age. 670 00:46:25,533 --> 00:46:27,966 For the ancient Greeks, the world was a place 671 00:46:28,066 --> 00:46:30,600 they shared with supernatural beings... 672 00:46:33,800 --> 00:46:36,466 Where a god could turn a mortal favorite 673 00:46:36,566 --> 00:46:38,666 into a constellation of stars... 674 00:46:40,200 --> 00:46:43,833 And the sun was driven across the sky each day 675 00:46:43,933 --> 00:46:46,066 in a fiery chariot. 676 00:46:46,166 --> 00:46:49,666 It was clearly the custom to explain 677 00:46:49,766 --> 00:46:51,833 the movements of the stars and planets 678 00:46:51,933 --> 00:46:54,133 through stories about gods and goddesses. 679 00:46:57,366 --> 00:47:00,600 These divine beings populate the great epic poems 680 00:47:00,700 --> 00:47:02,300 of early ancient Greece. 681 00:47:04,166 --> 00:47:06,300 Like other ancient people, 682 00:47:06,400 --> 00:47:08,433 the Greeks didn't regard the heavens 683 00:47:08,533 --> 00:47:10,666 as existing in some other dimension. 684 00:47:13,933 --> 00:47:17,766 Their stories tell of a shared world in which gods and mortals 685 00:47:17,866 --> 00:47:19,666 live alongside each other. 686 00:47:22,600 --> 00:47:25,000 Yet only the gods could freely plunge 687 00:47:25,100 --> 00:47:28,033 into the depths of the ocean, 688 00:47:28,133 --> 00:47:30,766 or make their home on the highest mountain. 689 00:47:34,233 --> 00:47:37,800 To humans, the heavens were out of bounds. 690 00:47:39,266 --> 00:47:41,800 Any mortal trying to reach the skies 691 00:47:41,900 --> 00:47:45,633 was in danger of incurring divine anger... 692 00:47:45,733 --> 00:47:47,700 And certain downfall. 693 00:47:52,666 --> 00:47:56,333 And perhaps no Greek myth is a better example of this idea 694 00:47:56,433 --> 00:48:01,466 than the story of a man called Daedalus and his son... 695 00:48:01,566 --> 00:48:02,666 Icarus. 696 00:48:05,433 --> 00:48:08,766 Daedalus flew ahead, like a bird. 697 00:48:11,433 --> 00:48:13,366 He urged the boy to follow, 698 00:48:13,466 --> 00:48:16,633 and showed him the dangerous art of flying. 699 00:48:29,300 --> 00:48:33,100 The boy began to delight in his daring flight 700 00:48:33,200 --> 00:48:37,266 and, drawn by desire for the heavens, soared higher. 701 00:48:46,800 --> 00:48:49,566 His nearness to the sun softened the wax 702 00:48:49,666 --> 00:48:51,400 that held the wings, 703 00:48:51,500 --> 00:48:53,300 and the wax melted. 704 00:48:57,133 --> 00:49:01,300 He flailed with bare arms, but could not ride the air. 705 00:49:04,533 --> 00:49:08,566 Even as his mouth cried his father's name, 706 00:49:08,666 --> 00:49:11,866 it vanished into the dark blue sea. 707 00:49:20,333 --> 00:49:22,233 It would be more than 2,000 years 708 00:49:22,333 --> 00:49:24,966 before man risked the wrath of the gods 709 00:49:25,066 --> 00:49:26,733 and again took to the skies. 710 00:49:28,433 --> 00:49:31,766 But even as Icarus' fabled feathers touched the water, 711 00:49:31,866 --> 00:49:36,066 the ancient Greeks had already set sail to trade, 712 00:49:36,166 --> 00:49:39,100 and colonize lands far beyond their own. 713 00:49:42,033 --> 00:49:44,833 Skilled sailors, they ventured overseas 714 00:49:44,933 --> 00:49:46,600 in search of new opportunity. 715 00:49:50,266 --> 00:49:53,333 As they did so, they increasingly came into contact 716 00:49:53,433 --> 00:49:54,800 with other cultures. 717 00:49:59,000 --> 00:50:01,400 They took the alphabet from the Phoenicians. 718 00:50:08,933 --> 00:50:11,200 They took artistic influences 719 00:50:11,300 --> 00:50:12,533 from the Egyptians. 720 00:50:18,366 --> 00:50:22,766 And from the Babylonians, they took astronomy. 721 00:50:24,766 --> 00:50:27,900 The Babylonian astronomy is a really strong current 722 00:50:28,000 --> 00:50:32,133 that flows into the Greek archaic culture. 723 00:50:32,233 --> 00:50:35,966 There's the planetary tables... The recording of 724 00:50:36,066 --> 00:50:38,833 planetary observations that influence really strongly 725 00:50:38,933 --> 00:50:41,633 the way that Greeks understand astronomy and do astronomy. 726 00:50:45,700 --> 00:50:47,166 Armed with astronomical knowledge 727 00:50:47,266 --> 00:50:48,833 from the Babylonians, 728 00:50:48,933 --> 00:50:53,200 the Greeks began to reinterpret the way they viewed the cosmos. 729 00:50:53,300 --> 00:50:57,400 They weren't just satisfied with observation and prediction. 730 00:50:57,500 --> 00:51:00,433 They wanted to know why the things they saw in the sky 731 00:51:00,533 --> 00:51:02,033 moved the way they did. 732 00:51:03,966 --> 00:51:07,442 - One man is often credited with being the person to provide - one man is often credited with being the person to provide 733 00:51:07,466 --> 00:51:10,933 The biggest change in our understanding of the cosmos. 734 00:51:11,033 --> 00:51:14,166 His name was Thales. 735 00:51:14,266 --> 00:51:18,066 Thales of Miletus is the person we tend to call 736 00:51:18,166 --> 00:51:19,633 the father of philosophy. 737 00:51:19,733 --> 00:51:23,466 He shifts the way in which Greeks think about 738 00:51:23,566 --> 00:51:26,033 asking questions about the natural world. 739 00:51:28,333 --> 00:51:31,733 Thales lived in the sixth century B.C. 740 00:51:31,833 --> 00:51:34,100 He was from Miletus, a Greek settlement 741 00:51:34,200 --> 00:51:36,266 on the shores of modern Turkey, 742 00:51:36,366 --> 00:51:37,600 that had direct access to 743 00:51:37,700 --> 00:51:40,033 the ideas and knowledge of the east. 744 00:51:44,166 --> 00:51:46,433 He is credited with being the first person 745 00:51:46,533 --> 00:51:48,533 to question the belief that the cosmos 746 00:51:48,633 --> 00:51:50,600 could be explained through mythology. 747 00:51:52,633 --> 00:51:55,000 For Thales and his fellow philosophers, 748 00:51:55,100 --> 00:51:57,600 every observable thing in the cosmos 749 00:51:57,700 --> 00:52:02,133 had to have a rational, scientific explanation. 750 00:52:02,233 --> 00:52:05,200 They believed this was as true for things in the skies, 751 00:52:05,300 --> 00:52:08,600 like the movements of the sun and the moon, 752 00:52:08,700 --> 00:52:12,100 as it was for things that happened on earth. 753 00:52:17,000 --> 00:52:19,033 He stops asking questions about 754 00:52:19,133 --> 00:52:21,900 individual phenomenon... 755 00:52:26,400 --> 00:52:29,966 This earthquake, that storm, this lightning bolt... 756 00:52:35,300 --> 00:52:38,966 And instead asks questions about phenomenon: 757 00:52:39,066 --> 00:52:42,433 Earthquakes, lightning bolts, storms. 758 00:52:44,666 --> 00:52:49,800 In the process, these phenomena cease to be supernatural 759 00:52:49,900 --> 00:52:52,833 or linked to supernatural gods 760 00:52:52,933 --> 00:52:55,533 and instead become natural. 761 00:52:55,633 --> 00:52:58,066 It's something that happens naturally. 762 00:53:00,333 --> 00:53:02,500 This was a pivotal moment 763 00:53:02,600 --> 00:53:06,566 in our scientific understanding of the universe. 764 00:53:06,666 --> 00:53:09,033 It was now possible to believe that 765 00:53:09,133 --> 00:53:11,166 everything we observed in the skies 766 00:53:11,266 --> 00:53:15,266 was part of the natural, not the supernatural world. 767 00:53:20,500 --> 00:53:24,266 What's amazing is we have such an incredible shift 768 00:53:24,366 --> 00:53:26,533 from the dark ages to this period 769 00:53:26,633 --> 00:53:28,833 when we have the birth of philosophy, 770 00:53:28,933 --> 00:53:30,500 the birth of science. 771 00:53:32,900 --> 00:53:36,500 This was the dawn of a new era in human history... 772 00:53:38,900 --> 00:53:43,933 Where we would change the way we view the world around us, 773 00:53:44,033 --> 00:53:48,366 the skies above, and everything in them... 774 00:53:50,066 --> 00:53:51,100 Forever. 775 00:54:11,933 --> 00:54:16,033 Our earth undergoes an epic transformation. 776 00:54:16,133 --> 00:54:18,700 The question isn't "is the earth round?" 777 00:54:18,800 --> 00:54:21,133 The question really is "how big is it?" 778 00:54:23,900 --> 00:54:25,433 We establish a mechanical model 779 00:54:25,533 --> 00:54:26,833 of the universe. 780 00:54:26,933 --> 00:54:28,500 Ptolemy sees the earth at the center, 781 00:54:28,600 --> 00:54:31,933 and then it's surrounded by a series of crystalline spheres. 782 00:54:33,466 --> 00:54:34,766 And we call into question 783 00:54:34,866 --> 00:54:37,700 our place at the center of it all. 784 00:54:37,800 --> 00:54:41,166 Humanity loses its position of centrality, so, 785 00:54:41,266 --> 00:54:43,300 philosophically and potentially theologically, 786 00:54:43,400 --> 00:54:44,400 this is quite radical. 787 00:54:54,233 --> 00:54:56,333 To order this program on DVD, 788 00:54:56,433 --> 00:55:00,033 visit shop pbs or call 1-800-play-pbs. 789 00:55:00,133 --> 00:55:02,466 Also available on Amazon prime video.