WEBVTT 1 00:00:03.483 --> 00:00:06.903 Up to now, astronauts and probes have brought nearly 2 00:00:06.903 --> 00:00:10.210 400 kilograms of moon rocks back to Earth. 3 00:00:10.310 --> 00:00:12.619 Where on the Moon did they come from? 4 00:00:12.630 --> 00:00:17.803 And how have they changed how we view our closest celestial neighbor? 5 00:00:18.070 --> 00:00:23.070 "The Moon is a history book that allows us to look far back into the past." 6 00:00:23.503 --> 00:00:29.390 Could the samples from China's 2024 Moon mission throw up new mysteries? 7 00:00:30.190 --> 00:00:34.510 "The Moon is still good for a surprise or two. We know a little. 8 00:00:34.510 --> 00:00:36.750 Scientist appetites have been whetted. 9 00:00:36.750 --> 00:00:40.006 But lunar research still has a long way to go." 10 00:00:47.790 --> 00:00:54.070 July, 1969. Apollo astronauts set off on the first mission to land on the Moon. 11 00:00:54.350 --> 00:00:58.983 Their destination: a lunar plain on the side of it that faces Earth. 12 00:01:04.300 --> 00:01:07.230 There was no way to practice a landing. 13 00:01:07.230 --> 00:01:10.080 Would the spacecraft touch down safely, 14 00:01:10.080 --> 00:01:13.416 or sink deep into dust and tip over? 15 00:01:24.209 --> 00:01:30.910 Success! Around 600 million people watched the historic event on television. 16 00:01:32.459 --> 00:01:37.500 Neil Armstrong and Buzz Aldrin spent 2.5 hours on the lunar surface. 17 00:01:37.500 --> 00:01:41.383 They carried out experiments and collected almost 22 kilograms 18 00:01:41.383 --> 00:01:44.043 of rocks to bring back to Earth. 19 00:01:44.430 --> 00:01:49.540 Traces of the mission are still visible on satellite photos taken today. 20 00:01:51.320 --> 00:01:55.680 NASA sent six crewed space missions in all to the Moon's surface. 21 00:01:56.240 --> 00:01:59.780 On the first flights, the focus was less on collecting samples, 22 00:01:59.780 --> 00:02:03.893 and more on landing safely in flat areas. 23 00:02:07.160 --> 00:02:11.520 Later trips also targeted areas that were more difficult to reach. 24 00:02:15.290 --> 00:02:19.617 But all the Apollo missions landed on the near side of the Moon, 25 00:02:19.639 --> 00:02:21.680 close to its equator. 26 00:02:24.470 --> 00:02:28.720 "Imagine if you had to describe Earth's geology based on 27 00:02:28.720 --> 00:02:32.120 just a few landing sites. You wouldn't see much. 28 00:02:32.120 --> 00:02:34.620 And it's the same for us with the Moon. 29 00:02:34.720 --> 00:02:38.240 The more landing sites – and the more samples we have 30 00:02:38.240 --> 00:02:41.760 from different sites – the better it is in the end." 31 00:02:45.040 --> 00:02:49.150 The Apollo 15 mission expanded horizons. 32 00:02:49.150 --> 00:02:54.290 Its astronauts were able to explore extensively for the first time with a lunar rover. 33 00:02:57.023 --> 00:03:00.303 And they collected much more rock than their predecessors – 34 00:03:00.303 --> 00:03:02.946 from a wider range of sites. 35 00:03:06.990 --> 00:03:10.990 The last mission in the series, Apollo 17, was the first with a scientist on board: 36 00:03:16.510 --> 00:03:19.450 Geologist Harrison Schmitt. 37 00:03:22.487 --> 00:03:27.750 He made a surprising discovery: orange material amidst all the gray. 38 00:03:27.910 --> 00:03:30.300 It would spur groundbreaking insights. 39 00:03:34.443 --> 00:03:39.477 In total, the Apollo astronauts brought more than 380 kilograms of 40 00:03:39.477 --> 00:03:43.623 moon rock back to Earth from six landing sites. 41 00:03:46.350 --> 00:03:49.800 The largest chunk is nicknamed 'Big Muley'. 42 00:03:49.800 --> 00:03:52.646 Like most of the other material from the Apollo missions, 43 00:03:52.646 --> 00:03:55.380 it's at a NASA facility in Houston. 44 00:03:55.840 --> 00:04:00.040 Lab samples are stored in nitrogen to protect them from moisture. 45 00:04:02.990 --> 00:04:07.430 The lunar samples give researchers glimpses into a far-distant past. 46 00:04:08.963 --> 00:04:15.370 "All of the Apollo samples allow us to look back about 4.4 billion years, 47 00:04:15.370 --> 00:04:19.190 a time of course very close to the formation of the planets. 48 00:04:19.750 --> 00:04:23.190 We think Earth formed 4.5 billion years ago. 49 00:04:23.190 --> 00:04:28.276 So that means we are very, very close to seeing what happened in the beginning." 50 00:04:29.040 --> 00:04:34.680 China's Chang'e 5 lunar probe launched in November 2020. 51 00:04:34.680 --> 00:04:37.960 Its mission: to bring samples back to Earth 52 00:04:37.960 --> 00:04:41.180 around five decades after the last Apollo mission. 53 00:04:43.170 --> 00:04:47.110 The targeted location was specifically chosen to provide 54 00:04:47.110 --> 00:04:50.750 missing data and fill in gaps in what we already know. 55 00:04:50.750 --> 00:04:56.470 Chang'e 5 landed in a volcanic area, and collected almost two kilograms of 56 00:04:56.480 --> 00:04:59.290 dust and rock for the long journey home. 57 00:05:03.800 --> 00:05:08.800 Its successor, Chang'e 6, was launched at the beginning of May 2024 58 00:05:08.800 --> 00:05:12.470 to collect rocks for the first time from the far side of the Moon. 59 00:05:13.029 --> 00:05:16.010 Geologists have been eager to have them for decades. 60 00:05:25.367 --> 00:05:29.000 In labs here on Earth, moon rocks could be examined with a range 61 00:05:29.000 --> 00:05:32.800 of highly sensitive methods able to precisely determine their 62 00:05:32.800 --> 00:05:34.640 age and composition. 63 00:05:37.020 --> 00:05:41.070 Even just looking at it in a light microscope told experts a lot about a 64 00:05:41.080 --> 00:05:43.320 rock's history and development. 65 00:05:43.757 --> 00:05:48.310 The composition of the minerals and their size showed, for example, 66 00:05:48.310 --> 00:05:52.430 at what depth the rock crystallized, and how quickly it cooled. 67 00:05:57.589 --> 00:06:01.750 The very first Apollo samples changed our view of our planet. 68 00:06:02.230 --> 00:06:06.430 They contained three previously unknown minerals. 69 00:06:06.430 --> 00:06:13.916 It later turned out that these "lunar minerals" also exist on Earth, but are quite rare. 70 00:06:16.320 --> 00:06:19.190 Most of the samples are well-documented. 71 00:06:19.200 --> 00:06:23.080 Photos and satellite images have been made of the sites they were taken 72 00:06:23.080 --> 00:06:25.710 from and their surroundings. 73 00:06:29.367 --> 00:06:33.000 With this data, researchers developed a method for determining 74 00:06:33.000 --> 00:06:36.220 the age of various parts of the moon's surface. 75 00:06:36.320 --> 00:06:41.080 The larger and more numerous the craters are, the older the area is. 76 00:06:45.747 --> 00:06:49.747 "I can date the entire Moon using this method, 77 00:06:49.747 --> 00:06:53.670 even when no humans have ever walked on a particular surface. 78 00:06:54.330 --> 00:06:57.810 And I can also apply the method to other celestial bodies. 79 00:06:57.890 --> 00:07:00.930 So I can also date Mercury and Mars. 80 00:07:01.250 --> 00:07:04.300 I can date the surface of an asteroid." 81 00:07:07.710 --> 00:07:13.120 The lunar samples have given us insights into the early days of our solar system. 82 00:07:13.120 --> 00:07:17.240 They can be used, for instance, to reconstruct when the nascent planets 83 00:07:17.240 --> 00:07:22.160 were struck by asteroids and comets, and how heavy the bombardment was. 84 00:07:22.950 --> 00:07:27.550 On Earth, tectonic movement drives rock underground, where it melts, 85 00:07:27.590 --> 00:07:30.690 erasing traces of our planet's early history. 86 00:07:30.750 --> 00:07:35.390 Water, vegetation and air also alter the surface. 87 00:07:39.070 --> 00:07:43.470 The samples collected even revealed the secret of the origin of our Moon. 88 00:07:43.830 --> 00:07:47.510 In the laboratory, it turned out that the moon rocks were very similar 89 00:07:47.510 --> 00:07:49.673 to terrestrial rocks. 90 00:07:54.450 --> 00:07:59.183 Until then, there were several theories about where our Moon came from. 91 00:07:59.280 --> 00:08:03.280 Now its rocks revealed that it was actually part of Earth. 92 00:08:09.207 --> 00:08:13.607 The evidence indicates that more than 4.5 billion years ago, 93 00:08:13.607 --> 00:08:17.160 a Mars-sized celestial body grazed our planet. 94 00:08:17.640 --> 00:08:21.120 Hot material from both bodies was hurled into space. 95 00:08:21.400 --> 00:08:23.390 This eventually formed the Moon. 96 00:08:26.863 --> 00:08:30.163 "It's thought that the cooling of the Moon's crust, 97 00:08:30.163 --> 00:08:34.153 so the formation of its upper crust happened very quickly – 98 00:08:34.153 --> 00:08:37.350 50 million years after the collision. 99 00:08:37.350 --> 00:08:40.040 Geologically, that's very fast. 100 00:08:40.150 --> 00:08:44.143 Of course, these are dimensions that we humans can't really imagine." 101 00:08:46.309 --> 00:08:50.210 In its early days, the Moon was bombarded heavily. 102 00:08:50.210 --> 00:08:54.600 The impacts left behind large craters, which were later flooded 103 00:08:54.600 --> 00:08:56.200 by rising magma. 104 00:08:58.809 --> 00:09:04.290 The rock cooled and formed the dark craters that give the Moon its face. 105 00:09:13.703 --> 00:09:19.803 Decades after the Apollo missions, researchers retrieved the samples from the archives 106 00:09:19.803 --> 00:09:23.243 and examined them using new methods. 107 00:09:24.670 --> 00:09:29.790 In this lump, they may have actually discovered the oldest Earth rock ever! 108 00:09:34.667 --> 00:09:40.373 A meteorite possibly hurled it from the still young Earth towards the Moon 109 00:09:40.373 --> 00:09:44.110 where it fused with this rock in another impact. 110 00:09:45.030 --> 00:09:49.283 And another groundbreaking discovery was made in the orange-colored material 111 00:09:49.283 --> 00:09:55.143 collected by Apollo 17: glass beads containing lunar water. 112 00:09:56.800 --> 00:10:01.080 "If we were to assume that the water came from the Earth, then it would 113 00:10:01.090 --> 00:10:05.080 naturally collect on the surface of the glass bead and not inside them. 114 00:10:05.360 --> 00:10:08.973 So in this respect, we are very sure that we actually have water 115 00:10:08.973 --> 00:10:13.163 from the Moon in these little glass beads." 116 00:10:15.309 --> 00:10:22.077 Volcanic eruptions brought lunar water with the magma to the Moon's surface. 117 00:10:23.030 --> 00:10:28.230 In the frigid vacuum, the hot droplets instantly froze into glass beads, 118 00:10:28.230 --> 00:10:31.320 trapping the water inside. 119 00:10:35.520 --> 00:10:40.200 The samples from the Chinese probe Chang'e 5 also hid some surprises. 120 00:10:40.800 --> 00:10:45.833 Researchers have discovered even more water in them than in the Apollo rocks – 121 00:10:45.833 --> 00:10:51.120 embedded in glass globules that were formed during meteorite impacts. 122 00:10:51.920 --> 00:10:57.200 They form water, release it again and might even drive a lunar water cycle! 123 00:11:00.477 --> 00:11:05.950 All these discoveries have made the Moon interesting again for researchers. 124 00:11:05.950 --> 00:11:10.550 After all, water is the most important resource for crewed space travel. 125 00:11:18.982 --> 00:11:22.982 One area in particular on the far side of the Moon has interested 126 00:11:22.990 --> 00:11:25.690 planetary geologists for decades. 127 00:11:26.030 --> 00:11:30.976 Rocks from there are now allowing them to look even further back in time than ever. 128 00:11:32.030 --> 00:11:37.470 The South Pole-Aitken Basin is almost 2500 kilometers in diameter. 129 00:11:37.630 --> 00:11:40.100 And about 13 kilometers deep! 130 00:11:43.670 --> 00:11:46.437 It formed more than four billion years ago 131 00:11:46.437 --> 00:11:49.270 when a huge asteroid crashed into the Moon. 132 00:11:49.650 --> 00:11:53.770 That shattered its crust and hurled material up onto the surface from 133 00:11:53.770 --> 00:11:55.510 deeper layers of rock. 134 00:11:55.929 --> 00:12:00.050 It's material that could provide new insights into the Earth! 135 00:12:03.850 --> 00:12:08.763 "We don't know exactly what the first rocks on Earth looked like, 136 00:12:08.763 --> 00:12:11.850 nor do we know exactly how old the Earth is. 137 00:12:11.850 --> 00:12:14.070 And only the Moon could tell us that. 138 00:12:14.090 --> 00:12:16.360 That means looking into the past. 139 00:12:16.370 --> 00:12:20.210 And if we have mantle material from the Moon, then we also know what 140 00:12:20.210 --> 00:12:23.440 magma was composed of right at the very beginning. 141 00:12:23.450 --> 00:12:27.290 Back when the Earth was very young and the Moon formed." 142 00:12:30.660 --> 00:12:35.160 The Apollo Crater is located in the Aitken Basin. 143 00:12:35.160 --> 00:12:40.720 China's most recent lunar probe, Chang'e 6, retrieved samples from this crater. 144 00:12:40.720 --> 00:12:44.360 Four robots worked together to make that possible. 145 00:12:45.080 --> 00:12:49.640 The space probe reached the moon's orbit in early May 2024. 146 00:12:49.640 --> 00:12:53.559 It took just under three weeks to touch down at its destination and 147 00:12:53.559 --> 00:12:59.740 drop off the lander robot, which reached the lunar surface on June 1. 148 00:13:03.756 --> 00:13:07.480 Months in advance, a relay satellite was positioned in lunar 149 00:13:07.480 --> 00:13:10.090 orbit to transmit the data to Earth. 150 00:13:10.429 --> 00:13:14.150 Radio signals can't reach the far side of the Moon directly. 151 00:13:15.870 --> 00:13:20.190 Using a special digging device and a drill, the lander robot collected 152 00:13:20.190 --> 00:13:23.130 around two kilograms of rock samples. 153 00:13:28.250 --> 00:13:32.370 A transporter then carried that precious cargo back to the probe, 154 00:13:32.370 --> 00:13:35.155 which brought the rock to Earth. 155 00:13:36.440 --> 00:13:39.640 Geologists are already eagerly awaiting data. 156 00:13:41.630 --> 00:13:46.070 "Of course, as a lunar geologist, I'm delighted that we've finally managed 157 00:13:46.070 --> 00:13:47.940 to bring back samples from this area. 158 00:13:47.950 --> 00:13:50.220 But I'm also a bit skeptical. 159 00:13:50.230 --> 00:13:53.170 It's very little – two kilos isn't much. 160 00:13:53.190 --> 00:13:58.190 And it's not entirely clear whether that's really enough to find the right material. 161 00:13:58.190 --> 00:14:03.123 But I'm assuming that it'll be so exciting that we'll go back and get some more." 162 00:14:05.920 --> 00:14:10.487 NASA astronauts have been training for years to collect samples on the Moon 163 00:14:10.487 --> 00:14:15.417 while scientists and engineers develop tools and transport containers – 164 00:14:15.417 --> 00:14:19.630 to prevent any contamination on the way to the laboratories. 165 00:14:24.030 --> 00:14:28.597 All of the major space-faring nations now have lunar plans. 166 00:14:29.260 --> 00:14:33.180 In the coming decades, stations are to be built at its South Pole. 167 00:14:33.180 --> 00:14:38.500 Crewed missions will reveal in even more detail how the Moon was formed 168 00:14:38.660 --> 00:14:43.833 and what our Earth looked like around four and a half billion years ago!