1 00:00:00,200 --> 00:00:02,400 Speaker 1: Hey, please take a second and leave us a review 2 00:00:02,480 --> 00:00:06,279 Speaker 1: on Apple Podcasts, Spotify, or wherever you listen to the podcast. 3 00:00:06,960 --> 00:00:11,040 Speaker 1: Thanks a lot. Hey, Welcome to Science Stuff, the production 4 00:00:11,160 --> 00:00:14,440 Speaker 1: of iHeartRadio. I'm poor, Hey Champ, and today we are 5 00:00:14,560 --> 00:00:22,040 Speaker 1: going to the Moon. You might think you know the moon, 6 00:00:22,360 --> 00:00:26,480 Speaker 1: but actually it is full of scientific mysteries. We're going 7 00:00:26,480 --> 00:00:28,920 Speaker 1: to be talking about where the moon came from, what 8 00:00:29,080 --> 00:00:31,720 Speaker 1: it's made out of, and what it can tell us 9 00:00:31,760 --> 00:00:35,519 Speaker 1: about how life started on Earth. So get ready to 10 00:00:35,560 --> 00:00:39,320 Speaker 1: go over the moon as we tackle the unanswered questions 11 00:00:39,440 --> 00:00:49,320 Speaker 1: about our mysterious moon enjoying. Hey everyone, Today we're talking 12 00:00:49,320 --> 00:00:53,640 Speaker 1: to doctor Matt Siegler. Doctor Ziegler is a planetary scientist 13 00:00:53,640 --> 00:00:56,760 Speaker 1: at the University of Hawaii who works on several missions 14 00:00:56,800 --> 00:01:00,680 Speaker 1: for NASA and the European Space Agency, including did You 15 00:01:00,840 --> 00:01:04,120 Speaker 1: Are the miss mission to put astronauts back on the Moon. 16 00:01:04,560 --> 00:01:07,600 Speaker 1: He's going to answer three questions for us. Number one, 17 00:01:07,920 --> 00:01:10,520 Speaker 1: where did the moon come from? As it turns out, 18 00:01:10,680 --> 00:01:13,840 Speaker 1: it's really unusual for us to have such a big moon. 19 00:01:14,480 --> 00:01:18,640 Speaker 1: Number two, why does the moon always faces the same way? 20 00:01:19,400 --> 00:01:23,160 Speaker 1: Wasn't always the case? And number three, why are we 21 00:01:23,240 --> 00:01:26,080 Speaker 1: going back to the moon? It turns out scientists have 22 00:01:26,160 --> 00:01:29,640 Speaker 1: identified a deep mystery about the Moon that might have 23 00:01:29,800 --> 00:01:34,560 Speaker 1: huge implications for space travel and our search for extraterrest 24 00:01:34,600 --> 00:01:40,280 Speaker 1: deal life. So here's my conversation with doctor Matt Siegler. Well, 25 00:01:40,280 --> 00:01:42,160 Speaker 1: thank you doctor Siegler for joining us again. 26 00:01:42,400 --> 00:01:43,399 Speaker 2: Okay, welcome. 27 00:01:44,040 --> 00:01:46,200 Speaker 1: The last time we talked it was New Year's and 28 00:01:46,240 --> 00:01:48,280 Speaker 1: we talked about how the Earth goes around the Sun. 29 00:01:48,640 --> 00:01:50,840 Speaker 1: And now we're getting close to the lunar New Year, 30 00:01:51,200 --> 00:01:53,520 Speaker 1: so I thought it would be interesting to talk about 31 00:01:53,520 --> 00:01:53,920 Speaker 1: the moon. 32 00:01:54,200 --> 00:01:58,440 Speaker 2: Okay, that's actually my specialties. That's great to talk about 33 00:01:58,480 --> 00:01:59,760 Speaker 2: something that I know. 34 00:02:01,640 --> 00:02:02,800 Speaker 1: Are you saying you're a lunatic? 35 00:02:03,280 --> 00:02:06,760 Speaker 2: Yes, yeah, we're proud to call ourselves lunatics. 36 00:02:08,200 --> 00:02:11,600 Speaker 1: Well, in what ways is our moon unusual in the 37 00:02:11,720 --> 00:02:12,400 Speaker 1: Solar System? 38 00:02:12,720 --> 00:02:17,000 Speaker 2: Okay? Well, the weirdest thing about our moon is how 39 00:02:17,040 --> 00:02:20,920 Speaker 2: big it is compared to Earth. There are a couple 40 00:02:20,960 --> 00:02:24,120 Speaker 2: of moons out there, some of Saturn's moons and a 41 00:02:24,120 --> 00:02:26,720 Speaker 2: couple of Jupiter's moons that are about the size of 42 00:02:26,760 --> 00:02:29,800 Speaker 2: our moon or even a little bigger. But those planets 43 00:02:29,840 --> 00:02:32,480 Speaker 2: are huge, right, you could fit I think it's thirteen 44 00:02:32,560 --> 00:02:35,760 Speaker 2: hundred earths inside of Jupiter, right, Wow, huh. And so 45 00:02:36,000 --> 00:02:39,320 Speaker 2: their biggest moon is a very small moon compared to 46 00:02:39,360 --> 00:02:41,200 Speaker 2: the size of its body, meaning. 47 00:02:41,040 --> 00:02:43,839 Speaker 1: Like if Jupiter had a moon that's proportionately the same 48 00:02:43,880 --> 00:02:46,400 Speaker 1: size as our moon, it would be like the size 49 00:02:46,400 --> 00:02:47,400 Speaker 1: of Saturn or something. 50 00:02:47,680 --> 00:02:50,079 Speaker 2: Yeah, it would be like the size of Neptune at least. 51 00:02:50,200 --> 00:02:53,799 Speaker 2: So yeah, And the only other planet that, if you 52 00:02:53,840 --> 00:02:55,880 Speaker 2: want to call it a planet that has a similar 53 00:02:56,000 --> 00:02:56,480 Speaker 2: is Pluto. 54 00:02:56,639 --> 00:02:56,880 Speaker 3: Right. 55 00:02:56,960 --> 00:02:59,120 Speaker 1: Oh, no, no, we don't talk about Pluto in this podcast. 56 00:02:59,280 --> 00:03:00,560 Speaker 2: You don't talk about about plu. 57 00:03:00,720 --> 00:03:01,360 Speaker 1: We don't know. 58 00:03:03,680 --> 00:03:06,880 Speaker 2: Pluto has a moon that's about a tenth of its 59 00:03:06,880 --> 00:03:08,000 Speaker 2: size or something like that. 60 00:03:08,120 --> 00:03:11,160 Speaker 1: But plut itself is very small, smaller than us, right, 61 00:03:11,240 --> 00:03:12,520 Speaker 1: smaller than our moon kind of. 62 00:03:12,880 --> 00:03:16,960 Speaker 2: Yeah, Pluto is around it could fit inside the continental US. 63 00:03:17,120 --> 00:03:18,440 Speaker 2: So it's a pretty small body. 64 00:03:18,600 --> 00:03:20,839 Speaker 1: Okay, Oh, that's a very polite way to say it. 65 00:03:20,840 --> 00:03:23,440 Speaker 1: It's a small body. Yes, yes, small body. 66 00:03:24,160 --> 00:03:27,480 Speaker 2: So that's the weirdest thing about our moon is how 67 00:03:27,480 --> 00:03:29,040 Speaker 2: big it is compared to us. 68 00:03:30,160 --> 00:03:33,639 Speaker 1: So that's the first mystery about the moon. Why is 69 00:03:33,680 --> 00:03:36,600 Speaker 1: it so big? None of the other planets have a 70 00:03:36,720 --> 00:03:37,760 Speaker 1: moon this big. 71 00:03:38,200 --> 00:03:38,840 Speaker 3: Why is that? 72 00:03:39,480 --> 00:03:43,520 Speaker 1: Well, as it turns out, Charles Darwin's Sun George Darwin 73 00:03:43,880 --> 00:03:45,000 Speaker 1: had a theory about that. 74 00:03:46,280 --> 00:03:48,680 Speaker 2: So that's actually a funny part of the history is 75 00:03:48,840 --> 00:03:51,800 Speaker 2: our moon is relatively large. It's about the size of 76 00:03:51,840 --> 00:03:55,920 Speaker 2: the Pacific Ocean basin, and so Charles Darwin's son, I 77 00:03:55,960 --> 00:03:59,440 Speaker 2: believe George Darwin first theorized that the Moon might have 78 00:03:59,600 --> 00:04:02,520 Speaker 2: been created from the Earth by being spit out of 79 00:04:02,520 --> 00:04:05,040 Speaker 2: the Pacific Ocean basin, and the Pacific Ocean was the 80 00:04:05,120 --> 00:04:09,360 Speaker 2: hole left behind. So that's a good way to remember 81 00:04:09,400 --> 00:04:11,080 Speaker 2: the size of the Moon is roughly the size of 82 00:04:11,080 --> 00:04:15,440 Speaker 2: the Pacific Ocean, because that was one of the first thoughts, Well, well, 83 00:04:16,040 --> 00:04:17,960 Speaker 2: we have a hole here on Earth that's about the 84 00:04:17,960 --> 00:04:18,720 Speaker 2: size of the moon. 85 00:04:19,120 --> 00:04:21,839 Speaker 1: Yeah, maybe that's came It was like a giant pimple 86 00:04:21,880 --> 00:04:24,800 Speaker 1: that just popped off the Earth. That was the theory, yes, yes, 87 00:04:25,440 --> 00:04:31,760 Speaker 1: or the Darwin giant pimple theory. Yeah, George Darwin didn't 88 00:04:31,839 --> 00:04:35,760 Speaker 1: quite get thinks is right as this famous dad Charles Darwin, 89 00:04:36,800 --> 00:04:37,440 Speaker 1: or did he? 90 00:04:39,040 --> 00:04:42,000 Speaker 2: Now we kind of think it's crazy, but really how 91 00:04:42,040 --> 00:04:45,440 Speaker 2: we think the moon formed now was not all that different. 92 00:04:45,560 --> 00:04:48,880 Speaker 2: It's just that that spitting out happened in a big 93 00:04:48,920 --> 00:04:52,560 Speaker 2: event when something the size of Mars or so collided 94 00:04:52,760 --> 00:04:57,520 Speaker 2: into the early Earth and caused that event where material 95 00:04:57,600 --> 00:04:59,480 Speaker 2: got spit out and formed the moon. 96 00:05:00,120 --> 00:05:03,039 Speaker 1: That's a wild theory, Like we have a moon that's 97 00:05:03,240 --> 00:05:06,479 Speaker 1: like gray white, but we think it happened because some 98 00:05:06,640 --> 00:05:09,960 Speaker 1: giant mini planet crashed into the original Earth. 99 00:05:10,120 --> 00:05:12,560 Speaker 2: Yeah, so that's the idea is the original early Solar 100 00:05:12,600 --> 00:05:15,400 Speaker 2: system was full of things that were flying all around, 101 00:05:15,600 --> 00:05:18,719 Speaker 2: and some of them collided into each other, and the 102 00:05:18,800 --> 00:05:21,760 Speaker 2: debris of that collision formed something kind of like a 103 00:05:21,880 --> 00:05:24,680 Speaker 2: ring of Saturn around the Earth. Right, it was a ring, 104 00:05:24,920 --> 00:05:27,360 Speaker 2: and then that coalesced together and became the Moon. 105 00:05:27,720 --> 00:05:29,520 Speaker 1: So like our Earth is a mix of those two 106 00:05:29,560 --> 00:05:31,600 Speaker 1: original planets, and the Moon is a mix of those 107 00:05:31,600 --> 00:05:32,600 Speaker 1: two original planets. 108 00:05:32,640 --> 00:05:33,120 Speaker 2: Exactly. 109 00:05:34,279 --> 00:05:37,640 Speaker 1: Yes, scientists think the way the moon form was that 110 00:05:37,720 --> 00:05:41,000 Speaker 1: a planet the size of Mars crashed into a pre 111 00:05:41,240 --> 00:05:44,920 Speaker 1: Earth planet about four and a half billion years ago, 112 00:05:45,320 --> 00:05:48,200 Speaker 1: and then the debris from that crash clumped together and 113 00:05:48,320 --> 00:05:51,960 Speaker 1: formed the Moon. But here's a big question, how do 114 00:05:52,040 --> 00:05:55,360 Speaker 1: we know that? What makes us think that's how the 115 00:05:55,400 --> 00:05:59,000 Speaker 1: Moon formed. Well, it turns out this idea started when 116 00:05:59,000 --> 00:06:01,520 Speaker 1: we first walked on the Moon. 117 00:06:02,520 --> 00:06:06,200 Speaker 2: And this explains basically what we found when the Apollo 118 00:06:06,240 --> 00:06:09,720 Speaker 2: samples were returned in the nineteen sixties and seventies. Huh, 119 00:06:10,240 --> 00:06:14,359 Speaker 2: was that a lot of the isotopes of atoms were 120 00:06:14,600 --> 00:06:17,640 Speaker 2: incredibly similar between the Earth and the Moon. 121 00:06:18,279 --> 00:06:19,360 Speaker 1: What do you mean isotopes? 122 00:06:19,560 --> 00:06:22,479 Speaker 2: So normally an atom will have the same number of 123 00:06:22,520 --> 00:06:26,000 Speaker 2: protons and neutrons, and so an isotope is one that 124 00:06:26,080 --> 00:06:28,480 Speaker 2: has different numbers of neutrons. 125 00:06:28,120 --> 00:06:30,840 Speaker 1: Okay than the normal one I see. And so it's 126 00:06:30,920 --> 00:06:34,239 Speaker 1: where for the isotopes on Earth to match the ones 127 00:06:34,279 --> 00:06:34,680 Speaker 1: on the Moon. 128 00:06:35,160 --> 00:06:37,839 Speaker 2: Yeah, So that turns out to be one of the 129 00:06:37,920 --> 00:06:42,080 Speaker 2: key identifiers of where something formed in the early Solar 130 00:06:42,120 --> 00:06:46,280 Speaker 2: System is it's the isotopes of its different atoms, and 131 00:06:46,400 --> 00:06:48,680 Speaker 2: particularly good one is oxygen. 132 00:06:49,960 --> 00:06:52,560 Speaker 1: It turns out you can tell exactly where in the 133 00:06:52,560 --> 00:06:56,240 Speaker 1: Solar System a piece of rock comes from by its isotopes. 134 00:06:56,760 --> 00:06:59,320 Speaker 1: Like a piece of rock has more of one kind 135 00:06:59,320 --> 00:07:02,360 Speaker 1: of oxygen or carbon, you can tell it came from 136 00:07:02,360 --> 00:07:06,480 Speaker 1: close to the Sun, or near Jupiter, or way out 137 00:07:06,640 --> 00:07:08,520 Speaker 1: at the edges of the Solar system. 138 00:07:09,400 --> 00:07:12,760 Speaker 2: So we think the whole Solar System essentially was a 139 00:07:12,760 --> 00:07:15,240 Speaker 2: big cloud of gas and dust that was leftover from 140 00:07:15,400 --> 00:07:18,640 Speaker 2: some other star that exploded, right, huh, And that cloud 141 00:07:18,800 --> 00:07:22,040 Speaker 2: kind of collust around the early Sun, and then when 142 00:07:22,080 --> 00:07:24,640 Speaker 2: that Sun turned on, you know, very early in the 143 00:07:24,680 --> 00:07:28,080 Speaker 2: Solar system four point six billion years ago, it heated 144 00:07:28,160 --> 00:07:33,560 Speaker 2: that cloud and basically boiled off different isotope ratios as 145 00:07:33,560 --> 00:07:36,760 Speaker 2: you went different distance from the Sun. And then when 146 00:07:36,760 --> 00:07:40,480 Speaker 2: the planets formed, out of those different isotopic ratios as 147 00:07:40,480 --> 00:07:42,920 Speaker 2: a function of distance away from the Sun, they seem 148 00:07:42,960 --> 00:07:47,040 Speaker 2: to have checked those isotopes permanently after that. 149 00:07:47,400 --> 00:07:51,440 Speaker 1: Interesting, it's like the rocks have a tag that says 150 00:07:51,560 --> 00:07:53,560 Speaker 1: where in the Solar System formed. 151 00:07:53,800 --> 00:07:59,000 Speaker 2: Yeah, so when we see a meteorite that we have 152 00:07:59,080 --> 00:08:03,640 Speaker 2: identified has come from Mars or a meteorite from the 153 00:08:03,680 --> 00:08:08,280 Speaker 2: Asteroid belt, these will have different oxygen isotope ratios than 154 00:08:08,560 --> 00:08:12,920 Speaker 2: the Earth. But the Moon has almost the same as 155 00:08:12,960 --> 00:08:17,520 Speaker 2: the Earth, like too incredible precision, such that the only 156 00:08:17,560 --> 00:08:20,280 Speaker 2: way that we can explain it was that they essentially 157 00:08:20,320 --> 00:08:24,560 Speaker 2: formed together as a single body. Okay, and so the 158 00:08:24,600 --> 00:08:27,559 Speaker 2: Earth and the Moon are incredibly similar, and it could 159 00:08:27,560 --> 00:08:29,960 Speaker 2: be that it's just kind of telling us they formed 160 00:08:29,960 --> 00:08:33,160 Speaker 2: at the exact same distance from the Sun. But the 161 00:08:33,200 --> 00:08:36,720 Speaker 2: precision in which they match seems to only be explained 162 00:08:36,720 --> 00:08:39,520 Speaker 2: if they really formed together in this idea of the 163 00:08:39,559 --> 00:08:42,679 Speaker 2: giant impact or simple. 164 00:08:44,080 --> 00:08:46,200 Speaker 1: I see the match is too good. It's just too 165 00:08:46,240 --> 00:08:47,280 Speaker 1: identical to the Earth. 166 00:08:47,360 --> 00:08:51,000 Speaker 2: Yeah, Like these are identical twins, you know, they had 167 00:08:51,080 --> 00:08:52,280 Speaker 2: to be born from the same mother. 168 00:08:53,040 --> 00:08:56,319 Speaker 1: I see the DNA says their siblings, same mother, same father. 169 00:08:56,720 --> 00:09:00,760 Speaker 2: Okay, And so there were lots of theory going around, 170 00:09:00,760 --> 00:09:02,920 Speaker 2: and as far as I understand it, there was some 171 00:09:03,160 --> 00:09:07,320 Speaker 2: international meeting about this in the early nineteen eighties and 172 00:09:07,360 --> 00:09:09,520 Speaker 2: there was a lot of debate, and then out came 173 00:09:09,679 --> 00:09:12,200 Speaker 2: the giant impact as the winner, and it's kind of 174 00:09:12,200 --> 00:09:13,440 Speaker 2: been the standard since then. 175 00:09:13,920 --> 00:09:16,600 Speaker 1: Interesting. So it's not like we have some smoking gun 176 00:09:16,640 --> 00:09:18,760 Speaker 1: that says that this is what happened, or that there 177 00:09:18,760 --> 00:09:21,480 Speaker 1: was a camera or somebody saw this happened. It's like, well, 178 00:09:21,559 --> 00:09:24,400 Speaker 1: we can't think of anything else, and this is the 179 00:09:24,400 --> 00:09:25,680 Speaker 1: only thing that we have left. 180 00:09:25,800 --> 00:09:28,960 Speaker 2: Yeah, and everything that we find out knew about the 181 00:09:28,960 --> 00:09:32,840 Speaker 2: Moon seems to fit with the theory of the giant impact. 182 00:09:33,120 --> 00:09:35,160 Speaker 2: Like what like one of the things we found out 183 00:09:35,360 --> 00:09:37,960 Speaker 2: was from seismometers on the Moon. We've been able to 184 00:09:37,960 --> 00:09:41,520 Speaker 2: figure out that the Moon has a fairly small iron core, right, 185 00:09:42,000 --> 00:09:44,840 Speaker 2: and the Earth actually has a really big iron core 186 00:09:45,679 --> 00:09:48,960 Speaker 2: for its size. And so where did this extra iron 187 00:09:49,000 --> 00:09:52,160 Speaker 2: on the Earth come from and the lack of iron 188 00:09:52,320 --> 00:09:54,920 Speaker 2: on the Moon come from. Well, it may have been 189 00:09:54,960 --> 00:09:57,280 Speaker 2: that you had this big impact and then more the 190 00:09:57,320 --> 00:10:00,400 Speaker 2: iron went into the big object than into the small 191 00:10:00,440 --> 00:10:00,640 Speaker 2: on it. 192 00:10:01,360 --> 00:10:01,640 Speaker 3: Oh. 193 00:10:01,720 --> 00:10:05,240 Speaker 1: I see, what do you think the junior Darwin would 194 00:10:05,280 --> 00:10:09,439 Speaker 1: feel now that you've disproven his theory and not lived 195 00:10:09,520 --> 00:10:11,360 Speaker 1: up to the greatness of the Darwin name. 196 00:10:12,840 --> 00:10:16,080 Speaker 2: I don't know. I think scientists by nature like to 197 00:10:16,120 --> 00:10:19,520 Speaker 2: know the truth or the facts about the matter, and 198 00:10:19,679 --> 00:10:22,040 Speaker 2: if an idea that we clung to turns out to 199 00:10:22,080 --> 00:10:23,920 Speaker 2: be wrong, we should kind of give it up. 200 00:10:24,080 --> 00:10:24,440 Speaker 3: Yeah. 201 00:10:24,480 --> 00:10:27,360 Speaker 2: So I think that was a strong philosophy of science 202 00:10:27,360 --> 00:10:28,720 Speaker 2: then and it still is today. 203 00:10:29,080 --> 00:10:32,439 Speaker 1: Nice all right, when we come back, we're going to 204 00:10:32,480 --> 00:10:35,520 Speaker 1: tackle the second big mystery about the moon, which is 205 00:10:35,960 --> 00:10:39,400 Speaker 1: why is the Moon always facing us the same way? 206 00:10:39,840 --> 00:10:42,200 Speaker 1: In case you haven't noticed, every time you look at 207 00:10:42,200 --> 00:10:44,640 Speaker 1: the Moon, no matter where you are on the planet 208 00:10:44,880 --> 00:10:46,920 Speaker 1: or what time of the month or year, it is, 209 00:10:47,480 --> 00:10:50,640 Speaker 1: the features on the Moon always look the same, even 210 00:10:50,679 --> 00:10:53,280 Speaker 1: though it's spinning around the Earth. How can it be 211 00:10:53,400 --> 00:10:56,160 Speaker 1: that it's training at just the right rate for it 212 00:10:56,200 --> 00:10:58,439 Speaker 1: to always look the same to us? 213 00:10:59,000 --> 00:10:59,719 Speaker 3: We'll answer that. 214 00:10:59,720 --> 00:11:02,120 Speaker 1: Question and more after the break. 215 00:11:02,559 --> 00:11:14,320 Speaker 3: We'll be right back. Hey, we'll come back. 216 00:11:15,760 --> 00:11:19,320 Speaker 1: We're answering questions about the moon, and so far we've 217 00:11:19,400 --> 00:11:21,599 Speaker 1: talked about where the moon came from four and a 218 00:11:21,640 --> 00:11:25,520 Speaker 1: half billion years ago and how scientists figured out what happened. 219 00:11:26,200 --> 00:11:28,720 Speaker 1: Now we're going to answer another big question about the moon, 220 00:11:28,960 --> 00:11:32,400 Speaker 1: which is why is the Moon always facing us the 221 00:11:32,480 --> 00:11:35,480 Speaker 1: same way? If you think about it, the Earth is 222 00:11:35,520 --> 00:11:38,400 Speaker 1: going around the Sun, but the Earth doesn't always face 223 00:11:38,480 --> 00:11:41,200 Speaker 1: the same way to the Sun. If you were standing 224 00:11:41,200 --> 00:11:43,680 Speaker 1: on the surface of the Sun, the Earth would look 225 00:11:43,720 --> 00:11:46,400 Speaker 1: like it's spinning and it would look different every time 226 00:11:46,640 --> 00:11:50,040 Speaker 1: you see it. But you can't say that about the Moon. 227 00:11:51,280 --> 00:11:54,199 Speaker 1: The features of the Moon always look the same to us. 228 00:11:54,720 --> 00:11:56,920 Speaker 1: The only people in history that have gotten in a 229 00:11:56,960 --> 00:12:00,200 Speaker 1: different view of the Moon are the Apollo astronauts that 230 00:12:00,320 --> 00:12:04,079 Speaker 1: went there back in the nineteen sixties. Well, the reason 231 00:12:04,280 --> 00:12:06,720 Speaker 1: that the Moon always looks the same to us, according 232 00:12:06,720 --> 00:12:09,400 Speaker 1: to Professor Matt Ziegler, has to do with the fact 233 00:12:09,480 --> 00:12:15,559 Speaker 1: that the Moon isn't round. Okay, next question, Matt, why 234 00:12:15,679 --> 00:12:18,400 Speaker 1: is the Moon always facing the same way to us? 235 00:12:18,720 --> 00:12:22,360 Speaker 2: Okay, So the moon is what we call tidally locked 236 00:12:23,040 --> 00:12:26,200 Speaker 2: which essentially means one side is always facing us. 237 00:12:26,280 --> 00:12:29,640 Speaker 1: Right. Is that another characteristic of science. 238 00:12:30,960 --> 00:12:33,200 Speaker 2: If you don't know, we give it a fancy name 239 00:12:33,280 --> 00:12:38,240 Speaker 2: and basically says this is all we know about it. Yeah. 240 00:12:38,280 --> 00:12:40,600 Speaker 2: So a lot of moons in the Solar System are 241 00:12:40,640 --> 00:12:42,040 Speaker 2: also tidally. 242 00:12:41,600 --> 00:12:43,640 Speaker 1: Locked, not just our moon. 243 00:12:43,760 --> 00:12:47,760 Speaker 2: Like Jupiter's moons gets large. Four moons are all tidally locked. 244 00:12:48,000 --> 00:12:51,880 Speaker 2: So one face of Io is always facing Jupiter, one 245 00:12:51,920 --> 00:12:54,120 Speaker 2: face of Europa is always facing Jupiter. 246 00:12:54,360 --> 00:12:57,320 Speaker 1: Whow, we're not alone. Our moon is not the only one. 247 00:13:00,040 --> 00:13:04,280 Speaker 1: The moon is what scientists call tidally locked, which basically 248 00:13:04,320 --> 00:13:08,719 Speaker 1: means it's always facing us the same way. But there 249 00:13:08,840 --> 00:13:11,480 Speaker 1: is a reason why this happens, and it has to 250 00:13:11,520 --> 00:13:14,960 Speaker 1: do with how gooey the Earth and the Moon are. 251 00:13:16,320 --> 00:13:21,120 Speaker 2: This happens essentially because of how gooey an object is. 252 00:13:21,600 --> 00:13:22,040 Speaker 3: Uh huh. 253 00:13:22,080 --> 00:13:25,800 Speaker 2: So if something's spinning and it's gooey inside, it can 254 00:13:25,840 --> 00:13:27,000 Speaker 2: dissipate energy. 255 00:13:27,160 --> 00:13:30,200 Speaker 1: Okay, meaning like if you were spinning a water balloon. 256 00:13:30,640 --> 00:13:34,040 Speaker 2: Yeah. Or a good analogy is if you're spinning a 257 00:13:34,400 --> 00:13:38,000 Speaker 2: hard boiled egg versus a normal egg. Right, the hard 258 00:13:38,040 --> 00:13:40,480 Speaker 2: boiled egg will spin and spin and spin, right, but 259 00:13:40,520 --> 00:13:43,640 Speaker 2: the non heart boiled egg will slow itself down pretty 260 00:13:43,679 --> 00:13:47,559 Speaker 2: quickly because that ah, yeah, that goo inside is kind 261 00:13:47,559 --> 00:13:50,679 Speaker 2: of churning around and dissipating energy of that spin. 262 00:13:51,040 --> 00:13:53,040 Speaker 1: I see, if I spin a raw egg in space, 263 00:13:53,280 --> 00:13:57,440 Speaker 1: it'll eventually slow down because the liquid inside is losing energy. 264 00:13:57,600 --> 00:14:01,520 Speaker 2: Yeah, And so something akin to this happens inside of 265 00:14:01,559 --> 00:14:04,520 Speaker 2: a body like the Moon that initially early on at 266 00:14:04,559 --> 00:14:07,880 Speaker 2: least had a large liquid inside of it, right. 267 00:14:07,880 --> 00:14:11,280 Speaker 1: Oh. It initially the Moon was gooey, oh yeah, because 268 00:14:11,280 --> 00:14:14,320 Speaker 1: it was formed from the giant impact right, which was 269 00:14:14,720 --> 00:14:19,000 Speaker 1: really hot and made a lot of things melt. What 270 00:14:19,120 --> 00:14:21,960 Speaker 1: doctor Ziegler is saying is that when the Moon formed, 271 00:14:22,120 --> 00:14:25,480 Speaker 1: it was probably spinning really fast, but the inside of 272 00:14:25,480 --> 00:14:29,720 Speaker 1: it was gooey. It was melted rock or lava. It 273 00:14:29,800 --> 00:14:32,520 Speaker 1: was still hot from one the huge collision that formed 274 00:14:32,520 --> 00:14:36,160 Speaker 1: the Moon happened, and that melted inside made the Moon 275 00:14:36,280 --> 00:14:37,200 Speaker 1: stop spinning. 276 00:14:37,920 --> 00:14:38,640 Speaker 3: It's sort of like. 277 00:14:38,600 --> 00:14:41,320 Speaker 1: If you take a regular plastic water bottle and you 278 00:14:41,400 --> 00:14:43,320 Speaker 1: try to toss it up into the air so that 279 00:14:43,400 --> 00:14:47,200 Speaker 1: it spins, it'll eventually stop spinning in mid air, and 280 00:14:47,240 --> 00:14:49,040 Speaker 1: that's because the water inside. 281 00:14:48,720 --> 00:14:50,120 Speaker 3: Of it slashes around. 282 00:14:50,880 --> 00:14:54,200 Speaker 1: Well, the same thing happened to the Moon, and actually 283 00:14:54,400 --> 00:14:56,720 Speaker 1: it's also happening to the Earth. 284 00:14:57,920 --> 00:15:00,520 Speaker 2: And the Moon is doing this today to the Earth. Actually, 285 00:15:01,400 --> 00:15:04,880 Speaker 2: and so the Earth is actually slowing down. Right, Our 286 00:15:04,960 --> 00:15:07,920 Speaker 2: day is twenty four hours now. It used to be 287 00:15:08,040 --> 00:15:11,120 Speaker 2: twenty two hours, and earlier on in the Earth's history 288 00:15:11,200 --> 00:15:15,000 Speaker 2: it was as short as four hours. So we think 289 00:15:15,040 --> 00:15:18,480 Speaker 2: when the Earth and Moon formed that the Earth day 290 00:15:18,600 --> 00:15:19,880 Speaker 2: was about four hours long. 291 00:15:20,280 --> 00:15:22,840 Speaker 1: Really, yeah, we were spinning that fast. 292 00:15:23,080 --> 00:15:26,360 Speaker 2: Yeah, and then the Moon has caused us to slow 293 00:15:26,360 --> 00:15:28,920 Speaker 2: down that we're now at twenty four hours a day. 294 00:15:29,320 --> 00:15:32,680 Speaker 2: What maybe in a billion years will be at twenty 295 00:15:32,720 --> 00:15:34,920 Speaker 2: five hours a day or something like that. Right. 296 00:15:35,080 --> 00:15:38,640 Speaker 1: Oh, so the reason the day feels this long is because. 297 00:15:38,400 --> 00:15:38,880 Speaker 3: Of the moon. 298 00:15:39,280 --> 00:15:40,520 Speaker 2: Yeah, it's the moon's fault. 299 00:15:40,880 --> 00:15:43,040 Speaker 1: You had a long day, Blame the moon. Howl of 300 00:15:43,080 --> 00:15:43,400 Speaker 1: the moon. 301 00:15:43,720 --> 00:15:46,640 Speaker 2: Yeah, but if your day was too short, if it 302 00:15:46,800 --> 00:15:48,920 Speaker 2: went by too fast, then think the moon. 303 00:15:49,000 --> 00:15:50,360 Speaker 1: Right, Oh yeah, that's right, that's right. 304 00:15:50,440 --> 00:15:53,200 Speaker 2: So the same way that the Earth day is slowly 305 00:15:53,200 --> 00:15:56,600 Speaker 2: getting longer because the Earth is slowing its spin, the 306 00:15:56,600 --> 00:15:59,440 Speaker 2: Moon went through something similar. It's just because the Moon 307 00:15:59,520 --> 00:16:03,000 Speaker 2: is a lot smaller, it happened a lot faster. Basically. 308 00:16:03,160 --> 00:16:06,840 Speaker 1: Okay, maybe take me back, So we had this big crash, 309 00:16:07,040 --> 00:16:09,320 Speaker 1: A lot of stuff went out there into space eventually 310 00:16:09,320 --> 00:16:12,760 Speaker 1: formed the moon. The moon had a squishy inside, meaning 311 00:16:12,800 --> 00:16:14,359 Speaker 1: like it was lava inside. 312 00:16:14,000 --> 00:16:17,440 Speaker 2: Right basically, right, Yeah, basically it's magma if it's not erupted. 313 00:16:19,000 --> 00:16:21,920 Speaker 1: Not the whole other episode. It was magma or lava 314 00:16:22,360 --> 00:16:25,280 Speaker 1: melted rock. It was melted rock, and it was spinning 315 00:16:25,440 --> 00:16:26,120 Speaker 1: super fast. 316 00:16:26,400 --> 00:16:26,720 Speaker 3: Yeah. 317 00:16:26,760 --> 00:16:29,400 Speaker 2: So we had a fast spinning Earth and a fast 318 00:16:29,400 --> 00:16:33,240 Speaker 2: spinning Moon, and basically them tugging on each other slowed 319 00:16:33,240 --> 00:16:35,800 Speaker 2: each other down. Okay, So if I was a live 320 00:16:35,920 --> 00:16:38,360 Speaker 2: bike there and on Earth, I would die because I 321 00:16:38,360 --> 00:16:41,360 Speaker 2: couldn't breathe and standing on lava. But if I could 322 00:16:41,360 --> 00:16:44,240 Speaker 2: somehow be there, my day would be four hours long, 323 00:16:44,600 --> 00:16:47,560 Speaker 2: and I would see the moon like basically spinning in place. 324 00:16:47,800 --> 00:16:50,040 Speaker 2: The Moon would look different every time I looked at it. Yeah, 325 00:16:50,080 --> 00:16:52,840 Speaker 2: you would see the far side of the moon back then. 326 00:16:53,160 --> 00:16:56,840 Speaker 1: Oh okay, And over time we slowed down and the 327 00:16:56,880 --> 00:17:00,119 Speaker 1: moon slowed down to the point where now it's always 328 00:17:00,160 --> 00:17:02,960 Speaker 1: looking at us the same way. Yes, So is it 329 00:17:03,160 --> 00:17:05,679 Speaker 1: just luck that we just happened to be alive at 330 00:17:05,680 --> 00:17:07,640 Speaker 1: a time when it's spinning. It just the right time 331 00:17:07,640 --> 00:17:09,720 Speaker 1: for it to be always looking at it, or is 332 00:17:09,760 --> 00:17:10,520 Speaker 1: it stuck there? 333 00:17:10,960 --> 00:17:13,640 Speaker 2: I wouldn't say it's that lucky, because we think it's 334 00:17:13,760 --> 00:17:17,840 Speaker 2: stuck very quickly, like in potentially a few thousand years 335 00:17:17,880 --> 00:17:20,919 Speaker 2: to less than a million years, Like the moon slowed 336 00:17:20,960 --> 00:17:24,840 Speaker 2: itself down very quickly. So the moon'spent tidally locked for 337 00:17:24,960 --> 00:17:28,920 Speaker 2: most of Earth's history, really, and then it got stuck there. Yeah, 338 00:17:28,960 --> 00:17:32,320 Speaker 2: and then it's been stuck there. And it's a little 339 00:17:32,440 --> 00:17:36,240 Speaker 2: arbitrary which side ended up stuck facing the Earth. And 340 00:17:36,280 --> 00:17:39,240 Speaker 2: that's still a debate of why the near side of 341 00:17:39,280 --> 00:17:40,480 Speaker 2: the Moon is the near side. 342 00:17:41,520 --> 00:17:43,800 Speaker 1: Okay, you might be wondering, if the Moon went from 343 00:17:43,840 --> 00:17:47,639 Speaker 1: spinning really fast to slowing down, why did it stop. 344 00:17:48,359 --> 00:17:50,840 Speaker 1: It's still going around to Earth, so why didn't the 345 00:17:50,880 --> 00:17:55,359 Speaker 1: Moon suddenly start spinning in place the other way? Well, 346 00:17:55,359 --> 00:17:57,840 Speaker 1: according to doctor Siegler, it all has to do with 347 00:17:57,920 --> 00:17:59,639 Speaker 1: the shape of the moon. 348 00:18:00,960 --> 00:18:03,840 Speaker 2: The Moon isn't a perfect sphere. It's kind of egg 349 00:18:03,920 --> 00:18:07,000 Speaker 2: shaped itself or what rugby ball shaped or whatever you 350 00:18:07,080 --> 00:18:09,280 Speaker 2: want to call it. Yeah, just slightly. 351 00:18:09,880 --> 00:18:13,040 Speaker 1: Yes, the Moon is not perfectly round. You might have 352 00:18:13,119 --> 00:18:16,400 Speaker 1: heard that the Earth is not perfectly round either. It's 353 00:18:16,440 --> 00:18:19,520 Speaker 1: a little wider around the middle or the equator. That's 354 00:18:19,600 --> 00:18:23,440 Speaker 1: because the Earth is spinning, and so it bulges out, but. 355 00:18:23,400 --> 00:18:24,520 Speaker 2: The Moon isn't round. 356 00:18:24,680 --> 00:18:28,399 Speaker 1: In a different way and for a different reason, the 357 00:18:28,480 --> 00:18:32,400 Speaker 1: Moon doesn't bulge out, it's actually stretched out. It looks 358 00:18:32,400 --> 00:18:35,880 Speaker 1: slightly closer to a rugby ball or an American football 359 00:18:35,880 --> 00:18:39,359 Speaker 1: ball with one of the pointy ends pointing at the Earth. 360 00:18:39,840 --> 00:18:42,480 Speaker 1: And the reason it's that shape isn't because it's spinning, 361 00:18:42,880 --> 00:18:46,080 Speaker 1: but because the Earth is pulling on it. As the 362 00:18:46,119 --> 00:18:49,200 Speaker 1: Moon goes in orbit around the Earth, the Earth's gravity 363 00:18:49,359 --> 00:18:51,560 Speaker 1: pulls on the Moon to keep it in that orbit, 364 00:18:51,920 --> 00:18:56,480 Speaker 1: and that causes the Moon to get stretched. And I 365 00:18:56,480 --> 00:18:59,600 Speaker 1: think I came up with a good analogy for tidal logging, 366 00:18:59,720 --> 00:19:01,240 Speaker 1: which is that sort of like if you're in a 367 00:19:01,280 --> 00:19:04,440 Speaker 1: merry go round and someone's at the edge and they're 368 00:19:04,560 --> 00:19:07,439 Speaker 1: about to fall off, like you grabbed their hand to 369 00:19:07,520 --> 00:19:10,119 Speaker 1: keep them in the merry go round, and so the 370 00:19:10,160 --> 00:19:13,000 Speaker 1: centropgal force is pulling them out, but I'm holding their 371 00:19:13,040 --> 00:19:17,240 Speaker 1: hand pulling them in, and so that causes them to stretch, right. 372 00:19:17,760 --> 00:19:20,679 Speaker 2: Okay, Yeah, that would be a good description of it. 373 00:19:20,800 --> 00:19:23,560 Speaker 1: Yeah, okay, And so that's what causes the Moon to 374 00:19:23,760 --> 00:19:25,800 Speaker 1: look sort of like a football shape pointing at us. 375 00:19:26,160 --> 00:19:29,439 Speaker 2: Yeah, and at some point in the Moon's history it 376 00:19:29,520 --> 00:19:33,280 Speaker 2: became solid enough, it cooled off enough that it froze 377 00:19:33,320 --> 00:19:35,679 Speaker 2: in a football shape at that time. 378 00:19:36,880 --> 00:19:40,679 Speaker 1: Okay, so here's what scientists think happened. There was a 379 00:19:40,720 --> 00:19:43,879 Speaker 1: pre Earth planet somewhere close to our current orbit. He 380 00:19:44,000 --> 00:19:46,639 Speaker 1: got smashed by another planet about the size of Mars. 381 00:19:47,520 --> 00:19:50,000 Speaker 1: Some of the debris stayed in place and became the Earth, 382 00:19:50,640 --> 00:19:53,119 Speaker 1: and some of the debris floated out in space and 383 00:19:53,200 --> 00:19:57,040 Speaker 1: became the Moon. This new Moon was an orbit around 384 00:19:57,080 --> 00:19:59,720 Speaker 1: the new Earth, but it was gooey and melted on 385 00:19:59,760 --> 00:20:02,960 Speaker 1: the inside. That made it stop spinning in place. And 386 00:20:03,119 --> 00:20:05,600 Speaker 1: because it was being pulled around in an orbit around 387 00:20:05,600 --> 00:20:08,400 Speaker 1: the Earth, it stretched out a little to be closer 388 00:20:08,440 --> 00:20:11,320 Speaker 1: to the shape of a football pointed back at the Earth. 389 00:20:11,800 --> 00:20:14,600 Speaker 1: Then it cooled off and it got stuck in that shape. 390 00:20:15,040 --> 00:20:17,280 Speaker 1: And once it got stuck in that shape, it became 391 00:20:17,359 --> 00:20:21,040 Speaker 1: tidally locked, with one end of the football always pointing. 392 00:20:20,920 --> 00:20:21,520 Speaker 3: At the Earth. 393 00:20:22,960 --> 00:20:24,720 Speaker 1: Wait, wait, wait, wait, I think what you're saying is 394 00:20:24,760 --> 00:20:27,199 Speaker 1: that just because of the particular history of when the 395 00:20:27,240 --> 00:20:30,600 Speaker 1: Moon cooled is the reason we're always seeing the same side. 396 00:20:30,640 --> 00:20:34,560 Speaker 1: Because if it had stay squisher longer. Maybe the moon 397 00:20:34,560 --> 00:20:36,600 Speaker 1: would be rounder now, less football. 398 00:20:36,240 --> 00:20:39,120 Speaker 2: Shape, maybe, but I think it would still become tidally 399 00:20:39,160 --> 00:20:40,119 Speaker 2: locked eventually. 400 00:20:40,280 --> 00:20:41,800 Speaker 3: Yeah. Okay, that's good. 401 00:20:42,000 --> 00:20:44,119 Speaker 2: That's a good thought. I have to think about that 402 00:20:44,160 --> 00:20:47,040 Speaker 2: one more than live on the air. 403 00:20:48,600 --> 00:20:50,080 Speaker 1: Am I gonna get my name in a paper? 404 00:20:50,119 --> 00:20:52,800 Speaker 2: Now? The cham. 405 00:20:54,960 --> 00:20:59,680 Speaker 1: The cham procrastinating hot football theory of moon tidal walking. Yes, 406 00:21:01,040 --> 00:21:02,800 Speaker 1: rolls off the tongue exactly. 407 00:21:03,600 --> 00:21:03,919 Speaker 3: Okay. 408 00:21:04,000 --> 00:21:06,880 Speaker 1: There are a couple of interesting things about this scenario. 409 00:21:07,280 --> 00:21:10,200 Speaker 1: The first is that the arrangement of having something football 410 00:21:10,280 --> 00:21:14,720 Speaker 1: shape pointing at you in orbit is stable, meaning that 411 00:21:14,760 --> 00:21:17,920 Speaker 1: if the football, for some reason tilton starts to point 412 00:21:17,960 --> 00:21:21,080 Speaker 1: in a different direction, the physics of the orbit will 413 00:21:21,119 --> 00:21:25,200 Speaker 1: make it snap back. Remember the analogy of keeping someone 414 00:21:25,200 --> 00:21:27,720 Speaker 1: from falling off a merry go round if they start 415 00:21:27,720 --> 00:21:30,760 Speaker 1: to twist or turn, the fact that you're grabbing their 416 00:21:30,840 --> 00:21:33,080 Speaker 1: hand and pulling on them towards the center of the 417 00:21:33,119 --> 00:21:36,640 Speaker 1: merry go round means to'll go back to the same position. 418 00:21:37,200 --> 00:21:39,600 Speaker 1: And that is why the moon is always facing us 419 00:21:39,640 --> 00:21:42,720 Speaker 1: the same way. We're basically looking at one of the 420 00:21:42,760 --> 00:21:46,320 Speaker 1: pointy ends of the football shaped moon. It's part of 421 00:21:46,359 --> 00:21:49,040 Speaker 1: the moon that we never see that's the other pointy 422 00:21:49,160 --> 00:21:53,879 Speaker 1: end of the football. Oh I see. So, like if 423 00:21:53,920 --> 00:21:55,840 Speaker 1: I took the moon right now and I flipped it 424 00:21:55,920 --> 00:21:58,359 Speaker 1: one to eighty degrees, we would be looking at the 425 00:21:58,400 --> 00:22:00,640 Speaker 1: different side of the moon, but it would stay locked 426 00:22:00,640 --> 00:22:05,480 Speaker 1: to that side of the moon. Yes, Oh, fascinating. Somebody 427 00:22:05,520 --> 00:22:06,359 Speaker 1: should do that, man. 428 00:22:06,680 --> 00:22:09,159 Speaker 2: Yeah, if they were like a giant impact or someone 429 00:22:09,359 --> 00:22:12,000 Speaker 2: crashed a really really big rocket into the Moon, that 430 00:22:12,000 --> 00:22:14,840 Speaker 2: they were enough to unlock it, you could have imagined 431 00:22:14,840 --> 00:22:16,680 Speaker 2: that it would lock again in that other way. 432 00:22:17,640 --> 00:22:19,800 Speaker 1: Like I'm tired of seeing this side of the moon, Like, 433 00:22:19,960 --> 00:22:22,320 Speaker 1: I'm done with it, Let's see the other side. Somebody's 434 00:22:22,320 --> 00:22:24,480 Speaker 1: give it a little push and it'll lock back to 435 00:22:24,560 --> 00:22:26,240 Speaker 1: the other side exactly. Yeah. 436 00:22:27,080 --> 00:22:27,399 Speaker 3: Okay. 437 00:22:27,440 --> 00:22:29,280 Speaker 1: You might be wondering, why would I want to look 438 00:22:29,359 --> 00:22:31,960 Speaker 1: at the other side of the moon? Is it really 439 00:22:31,960 --> 00:22:35,199 Speaker 1: that different? Well, it turns out that it is different, 440 00:22:35,480 --> 00:22:37,960 Speaker 1: and scientists don't really know why. 441 00:22:38,680 --> 00:22:40,760 Speaker 2: But there are all these weird things we've learned about 442 00:22:40,800 --> 00:22:42,880 Speaker 2: the moon. Now, is that the crust on the far 443 00:22:42,960 --> 00:22:45,000 Speaker 2: side of the moon is a lot thicker than the 444 00:22:45,040 --> 00:22:47,560 Speaker 2: crust on the near side of the moon. Whoa, and 445 00:22:48,160 --> 00:22:49,720 Speaker 2: like the near side of the moon has all the 446 00:22:49,800 --> 00:22:53,159 Speaker 2: lava flows right far side has none of that? What? 447 00:22:53,960 --> 00:22:56,120 Speaker 2: And so why did the near side of the moon 448 00:22:56,160 --> 00:22:58,280 Speaker 2: and the far side of the moon end up so different? 449 00:22:58,840 --> 00:23:01,800 Speaker 2: And is that because of the tidal locking or is 450 00:23:01,840 --> 00:23:05,600 Speaker 2: it a cause of why we tidally locked with this face? 451 00:23:05,880 --> 00:23:08,719 Speaker 1: Did it tidally lock because one side is different than 452 00:23:08,720 --> 00:23:10,560 Speaker 1: the other? Or is one side different than the other 453 00:23:10,720 --> 00:23:14,119 Speaker 1: because it's going around the Earth always facing the same way. 454 00:23:14,240 --> 00:23:18,160 Speaker 2: Yeah, And there are different ideas about what caused that difference. 455 00:23:18,240 --> 00:23:20,800 Speaker 2: That the Moon might have had a giant impact of 456 00:23:20,840 --> 00:23:25,679 Speaker 2: its own that created the difference originally, or that just 457 00:23:25,920 --> 00:23:28,439 Speaker 2: imagine you tidally locked when you're still really close to 458 00:23:28,480 --> 00:23:30,760 Speaker 2: the Earth and the Earth is still a molten ball 459 00:23:30,800 --> 00:23:35,480 Speaker 2: of lava, but it really heats one side more than 460 00:23:35,560 --> 00:23:38,320 Speaker 2: the other. Yeah, and that could cause a difference. So 461 00:23:38,359 --> 00:23:40,520 Speaker 2: there are a number of theories out there of how 462 00:23:40,600 --> 00:23:43,560 Speaker 2: that would cause the near side on the far side 463 00:23:43,640 --> 00:23:45,600 Speaker 2: to be different in the way they are. 464 00:23:47,920 --> 00:23:50,359 Speaker 1: In other words, we sort of know why the moon 465 00:23:50,520 --> 00:23:53,120 Speaker 1: is always facing us the same way, but we don't 466 00:23:53,160 --> 00:23:56,280 Speaker 1: know why it's this side of the Moon that's facing us. 467 00:23:56,760 --> 00:23:59,680 Speaker 1: It could have been random, or there could be more things, 468 00:23:59,800 --> 00:24:04,160 Speaker 1: but the moon and its history that we don't know about. Okay, 469 00:24:04,200 --> 00:24:06,439 Speaker 1: when we come back, we're going to tackle the last 470 00:24:06,600 --> 00:24:10,600 Speaker 1: mystery of the Moon, and it's a big one. It's 471 00:24:10,640 --> 00:24:13,719 Speaker 1: a secret that could determine the future of space travel 472 00:24:14,080 --> 00:24:17,639 Speaker 1: and it could help us understand the reason why there's 473 00:24:17,800 --> 00:24:20,720 Speaker 1: life on Earth. So stay with us. 474 00:24:21,160 --> 00:24:22,120 Speaker 3: We'll be right back. 475 00:24:32,720 --> 00:24:35,680 Speaker 1: Hey, welcome back. We're not going to tackle the big 476 00:24:35,760 --> 00:24:39,320 Speaker 1: open questions about the Moon. It turns out there's a 477 00:24:39,320 --> 00:24:42,159 Speaker 1: lot we don't know about the Moon, including a question 478 00:24:42,400 --> 00:24:45,480 Speaker 1: that might have huge implications for the future of space 479 00:24:45,520 --> 00:24:49,160 Speaker 1: travel and what we know about how life started on Earth. 480 00:24:49,720 --> 00:24:53,320 Speaker 1: Here's doctor Matt Ziegler, a planetary scientist involved in the 481 00:24:53,359 --> 00:25:01,359 Speaker 1: New Artemis mission stake astronauts back to the Moon. Okay, Matt, 482 00:25:01,720 --> 00:25:04,359 Speaker 1: what don't we know about the Moon? What are some 483 00:25:04,400 --> 00:25:06,639 Speaker 1: of the biggest mysteries we're trying to figure out right now? 484 00:25:06,840 --> 00:25:11,320 Speaker 2: Oh? Yeah, that depends on which subdiscipline of lunar science 485 00:25:11,359 --> 00:25:11,720 Speaker 2: you're in. 486 00:25:11,840 --> 00:25:15,520 Speaker 1: I think, really, what flavor of lunatic are you? So? 487 00:25:16,240 --> 00:25:18,520 Speaker 2: One thing we don't know about is what's on the 488 00:25:18,560 --> 00:25:19,440 Speaker 2: interior of the Moon. 489 00:25:19,680 --> 00:25:20,159 Speaker 1: We don't know. 490 00:25:20,640 --> 00:25:22,919 Speaker 2: Yeah, we have lots of pictures of the surface of 491 00:25:22,920 --> 00:25:25,320 Speaker 2: the Moon. We know that sometimes stuff came up from 492 00:25:25,320 --> 00:25:27,200 Speaker 2: the surface of the moon, But we want to figure 493 00:25:27,240 --> 00:25:30,560 Speaker 2: out what's going on inside of the moon and how. 494 00:25:30,359 --> 00:25:32,440 Speaker 1: Wait wait before in the episode, you told me that 495 00:25:32,640 --> 00:25:34,760 Speaker 1: we know how much iron is inside the moon. 496 00:25:35,119 --> 00:25:38,120 Speaker 2: Yeah, we know kind of basic things that like, the 497 00:25:38,119 --> 00:25:41,800 Speaker 2: moon has these different layers and they're about this big. 498 00:25:42,080 --> 00:25:44,560 Speaker 2: And we know that because in the nineteen seventies we 499 00:25:44,640 --> 00:25:48,800 Speaker 2: had seismometers around the moon that we're recording moonquakes. 500 00:25:49,080 --> 00:25:49,520 Speaker 3: Uh huh. 501 00:25:49,520 --> 00:25:53,719 Speaker 2: And so from listening to a moonquake, you can tell 502 00:25:54,000 --> 00:25:56,159 Speaker 2: kind of how thick the different layers are, what the 503 00:25:56,200 --> 00:25:59,800 Speaker 2: density of the interior is, but you don't really know 504 00:25:59,840 --> 00:26:03,400 Speaker 2: the composition entirely. You're kind of guessing based on density. 505 00:26:03,640 --> 00:26:05,200 Speaker 2: And so one of the ways you can figure out 506 00:26:05,200 --> 00:26:08,920 Speaker 2: the composition is by measuring how much heat is coming out. 507 00:26:09,760 --> 00:26:12,320 Speaker 1: Yes, it turns out we don't know exactly what the 508 00:26:12,440 --> 00:26:15,760 Speaker 1: inside of the Moon is made out of. So one 509 00:26:15,800 --> 00:26:18,359 Speaker 1: project doctor Siger is working on is to take the 510 00:26:18,400 --> 00:26:22,760 Speaker 1: moon's temperature. There are radioactive elements inside the Moon that 511 00:26:22,800 --> 00:26:26,280 Speaker 1: are giving off heat, and so by burying thermometers all 512 00:26:26,320 --> 00:26:29,920 Speaker 1: over the moon, you could reconstruct what all those radioactive 513 00:26:29,920 --> 00:26:31,080 Speaker 1: elements are. 514 00:26:32,560 --> 00:26:35,840 Speaker 2: And just this last year about a year ago now, 515 00:26:35,920 --> 00:26:39,280 Speaker 2: we had the first geothermal heat flow probe since then 516 00:26:39,520 --> 00:26:42,119 Speaker 2: land on the Moon with one of these missions that's 517 00:26:42,240 --> 00:26:43,680 Speaker 2: kind of leading up to Artemis. 518 00:26:44,200 --> 00:26:46,600 Speaker 1: Basically, we put a thermometer on the Moon. 519 00:26:46,880 --> 00:26:50,160 Speaker 2: Yeah, we drilled the thermometer about a meter down below 520 00:26:50,200 --> 00:26:53,320 Speaker 2: the nerve. And if we do this in enough locations 521 00:26:53,440 --> 00:26:55,719 Speaker 2: around the Moon, we can start to put together this 522 00:26:55,840 --> 00:26:59,400 Speaker 2: picture of how the heat producing elements are different around 523 00:26:59,480 --> 00:27:00,159 Speaker 2: the whole Moon. 524 00:27:00,440 --> 00:27:03,119 Speaker 1: Okay, And so the mystery is what exactly's in there? 525 00:27:03,240 --> 00:27:04,520 Speaker 1: What could be inside the moon? 526 00:27:04,760 --> 00:27:07,480 Speaker 2: Yeah? Is the material in the Moon the same or 527 00:27:07,520 --> 00:27:10,280 Speaker 2: different than the material deep inside of Earth? Right? And 528 00:27:10,320 --> 00:27:13,120 Speaker 2: that gets back to this idea did the Moon form 529 00:27:13,200 --> 00:27:13,800 Speaker 2: from the Earth? 530 00:27:14,080 --> 00:27:14,240 Speaker 1: Right? 531 00:27:14,359 --> 00:27:17,879 Speaker 2: We know that these oxygen isotopes and sauch are telling 532 00:27:17,960 --> 00:27:20,240 Speaker 2: us that the Moon and the Earth seemed to form together, 533 00:27:20,359 --> 00:27:22,960 Speaker 2: but the composition of the deep interior is going to 534 00:27:23,040 --> 00:27:25,960 Speaker 2: be another data point telling us did they form from 535 00:27:26,000 --> 00:27:26,720 Speaker 2: the same spot? 536 00:27:26,880 --> 00:27:28,600 Speaker 1: I see, what if you find that the inside of 537 00:27:28,640 --> 00:27:32,000 Speaker 1: the Moon is made out of cheese. 538 00:27:31,920 --> 00:27:34,359 Speaker 2: Well then then we better go there and mind the cheese. 539 00:27:36,720 --> 00:27:40,960 Speaker 2: It's hard milking cows. And I don't know, I think 540 00:27:41,000 --> 00:27:44,520 Speaker 2: it still might be cheaper to get cheese from cows 541 00:27:44,520 --> 00:27:45,000 Speaker 2: on the Earth. 542 00:27:45,119 --> 00:27:47,280 Speaker 1: But I don't know, but it's moon cheese. You can 543 00:27:47,400 --> 00:27:50,080 Speaker 1: charge your premium, Yes, exactly. 544 00:27:52,119 --> 00:27:53,680 Speaker 3: Okay. The last mystery. 545 00:27:53,320 --> 00:27:56,359 Speaker 1: Doctor Seeger brought up about the Moon is a pretty 546 00:27:56,359 --> 00:27:59,399 Speaker 1: interesting one. It's tied to the new Artemis missions that 547 00:27:59,440 --> 00:28:02,040 Speaker 1: you might have seen in the news, where we're bringing 548 00:28:02,119 --> 00:28:06,040 Speaker 1: astronauts back to the Moon and what they find could 549 00:28:06,119 --> 00:28:09,040 Speaker 1: revolutionize the future of space travel. 550 00:28:10,480 --> 00:28:12,679 Speaker 2: I would say. Another big mystery and one of the 551 00:28:12,680 --> 00:28:16,719 Speaker 2: big motivators of the Artemis program coming up to the 552 00:28:16,760 --> 00:28:20,800 Speaker 2: Moon and the whole international exploration of the Moon is 553 00:28:20,800 --> 00:28:22,600 Speaker 2: is their ice at the poles of the Moon. 554 00:28:23,040 --> 00:28:24,280 Speaker 1: Oh, we don't know. 555 00:28:24,680 --> 00:28:27,960 Speaker 2: No, So we have craters, and because the Moon has 556 00:28:28,000 --> 00:28:30,760 Speaker 2: a very low tilt, a crater near the pole will 557 00:28:30,840 --> 00:28:33,040 Speaker 2: literally be a place where the sun don't shine. 558 00:28:33,200 --> 00:28:35,920 Speaker 1: Right, I see, it's the moon hole. The moon hill 559 00:28:35,960 --> 00:28:39,360 Speaker 1: is where the sun don't shine. Yes, yes, it turns 560 00:28:39,400 --> 00:28:42,040 Speaker 1: out there might be places on the Moon with water 561 00:28:42,160 --> 00:28:44,840 Speaker 1: on it. At the north and south poles of the Moon, 562 00:28:45,160 --> 00:28:47,760 Speaker 1: there are craters so deep that they never get hit 563 00:28:47,800 --> 00:28:50,680 Speaker 1: by light from the sun, and because they never feel 564 00:28:50,680 --> 00:28:53,560 Speaker 1: the heat of the sun, they are super cold, which 565 00:28:53,640 --> 00:28:55,600 Speaker 1: means they could be full of ice. 566 00:28:56,920 --> 00:28:59,400 Speaker 2: And so these places on the surface of the Moon, 567 00:28:59,560 --> 00:29:03,040 Speaker 2: because get no direct sunlight, actually can be colder than 568 00:29:03,080 --> 00:29:06,920 Speaker 2: like the surface of Pluto. Whoa, And so any water 569 00:29:07,080 --> 00:29:10,680 Speaker 2: molecules that land there, you know, maybe a comet hit 570 00:29:10,720 --> 00:29:13,120 Speaker 2: the Moon, or maybe an asteroid that had like water 571 00:29:13,360 --> 00:29:16,800 Speaker 2: in its rock materials hit the Moon. Ah, that water 572 00:29:16,920 --> 00:29:18,680 Speaker 2: should stick at the poles. 573 00:29:19,760 --> 00:29:22,720 Speaker 1: That's right, there could be huge lakes of ice inside 574 00:29:22,720 --> 00:29:25,600 Speaker 1: of craters in the North and South poles of the Moon. 575 00:29:25,960 --> 00:29:27,920 Speaker 1: You might have heard on a previous episode of this 576 00:29:28,000 --> 00:29:31,720 Speaker 1: podcast or somewhere else that scientists think most of the 577 00:29:31,760 --> 00:29:34,840 Speaker 1: water that we have here on Earth actually came from 578 00:29:34,920 --> 00:29:38,200 Speaker 1: asteroids or comets that flew here from the far edges 579 00:29:38,240 --> 00:29:40,640 Speaker 1: of the Solar System. In other words, most of the 580 00:29:40,680 --> 00:29:43,640 Speaker 1: water that you drink that makes up your body could 581 00:29:43,680 --> 00:29:47,880 Speaker 1: be important. Well, the same thing probably happened on the Moon. 582 00:29:48,360 --> 00:29:50,920 Speaker 1: Must have also been hit with comets and asteroids full 583 00:29:50,960 --> 00:29:54,360 Speaker 1: of water, except that on the Moon, because there's no atmosphere, 584 00:29:54,800 --> 00:29:58,040 Speaker 1: most of that water probably evaporated into space when it 585 00:29:58,080 --> 00:30:02,640 Speaker 1: got hit by sunlight, except potentially in the craters on 586 00:30:02,720 --> 00:30:04,720 Speaker 1: the north and South poles of the Moon. 587 00:30:05,240 --> 00:30:06,360 Speaker 3: And if there's water. 588 00:30:06,120 --> 00:30:10,120 Speaker 1: There, it could have a big impact onto things. The 589 00:30:10,160 --> 00:30:16,520 Speaker 1: first is space traveling, and we're hoping that that ice 590 00:30:16,680 --> 00:30:19,160 Speaker 1: is there, both because we want, you know, astronauts to 591 00:30:19,240 --> 00:30:22,400 Speaker 1: drink martinis on the Moon and could generally stay alive 592 00:30:22,560 --> 00:30:23,600 Speaker 1: and hydrated. 593 00:30:23,280 --> 00:30:26,400 Speaker 2: Yes, and hydrated, and also that if you saw the 594 00:30:26,440 --> 00:30:29,720 Speaker 2: Space Shuttle ever launch, it had a big cloud coming out. 595 00:30:30,000 --> 00:30:34,080 Speaker 2: What that was was mostly steam. Right, So water is 596 00:30:34,200 --> 00:30:34,880 Speaker 2: rocket fuel. 597 00:30:35,120 --> 00:30:39,080 Speaker 1: You could make rocket fuel out of water. Yeah, that's right. 598 00:30:39,200 --> 00:30:42,479 Speaker 1: You can turn water into rocket fuel. It's a process 599 00:30:42,560 --> 00:30:46,160 Speaker 1: called electrolysis where you separate the H two O into 600 00:30:46,400 --> 00:30:49,480 Speaker 1: H and oh, and once you have oxygen gas and 601 00:30:49,600 --> 00:30:53,280 Speaker 1: hydrogen gas, it can burn those to push rockets further 602 00:30:53,360 --> 00:30:54,520 Speaker 1: out into space. 603 00:30:55,960 --> 00:30:59,520 Speaker 2: So basically, if we can find enough ice on the Moon, 604 00:31:00,040 --> 00:31:03,560 Speaker 2: the Moon also becomes a fueling station for our exploration 605 00:31:03,640 --> 00:31:07,600 Speaker 2: of the universe. Right, that's wow. That's another exciting thing 606 00:31:07,640 --> 00:31:08,120 Speaker 2: about it. 607 00:31:09,040 --> 00:31:11,600 Speaker 1: And the other exciting thing about finding water on the 608 00:31:11,640 --> 00:31:14,840 Speaker 1: Moon is that if there is water there in deep craters, 609 00:31:15,160 --> 00:31:18,040 Speaker 1: it would be sort of an untouched record how water 610 00:31:18,160 --> 00:31:22,360 Speaker 1: came to our solar system neighborhood billions of years ago. 611 00:31:23,360 --> 00:31:27,240 Speaker 2: It's kind of like flypaper and it essentially should record 612 00:31:27,440 --> 00:31:30,160 Speaker 2: the delivery of this water to the Moon. 613 00:31:30,920 --> 00:31:33,360 Speaker 1: It might tell us like, yes, we did get water 614 00:31:33,480 --> 00:31:35,960 Speaker 1: from asteroids or comets. 615 00:31:35,560 --> 00:31:38,160 Speaker 2: Yeah, and tell us you know where the sources of 616 00:31:38,200 --> 00:31:41,400 Speaker 2: our water came from. Yeah, And this is really important 617 00:31:41,440 --> 00:31:45,200 Speaker 2: for understanding the big pictures of like, well, could there 618 00:31:45,240 --> 00:31:48,480 Speaker 2: be life somewhere else out there? Right, because now we're 619 00:31:48,480 --> 00:31:51,480 Speaker 2: finding all these other solar systems. And did the same 620 00:31:51,600 --> 00:31:55,840 Speaker 2: thing that caused water to somehow come from outside the 621 00:31:55,880 --> 00:31:59,920 Speaker 2: outer Solar System to Earth? Is that a common process 622 00:32:00,040 --> 00:32:02,320 Speaker 2: that happens in every solar system or is it a 623 00:32:02,360 --> 00:32:05,320 Speaker 2: weird thing that only happened in our Solar system? 624 00:32:05,560 --> 00:32:05,760 Speaker 3: Yeah? 625 00:32:05,960 --> 00:32:08,040 Speaker 2: That you would have a planet that's warm enough to 626 00:32:08,080 --> 00:32:11,440 Speaker 2: live on because we're close but also wet. 627 00:32:11,760 --> 00:32:14,640 Speaker 1: We want to know more about why Earth has water 628 00:32:14,880 --> 00:32:17,200 Speaker 1: because water is the key ingredient in life. 629 00:32:17,520 --> 00:32:22,040 Speaker 2: Yes, and the Moon holds a record of water that 630 00:32:22,120 --> 00:32:23,000 Speaker 2: the Earth does not. 631 00:32:23,280 --> 00:32:25,760 Speaker 1: You're making the Moon seem like a really good tourist stop, 632 00:32:26,000 --> 00:32:27,880 Speaker 1: Like it might have fuel for you to go to 633 00:32:27,920 --> 00:32:30,760 Speaker 1: other parts of the universe. It might have some good 634 00:32:30,960 --> 00:32:33,840 Speaker 1: history so you can read while you're there. Yeah, and 635 00:32:34,040 --> 00:32:38,360 Speaker 1: it might have some cheese inside also for your snacks. Exactly. 636 00:32:38,920 --> 00:32:41,600 Speaker 2: Yeah, So in a thousand years, the Moon might be 637 00:32:41,640 --> 00:32:46,520 Speaker 2: the wall drugs. You'll see signs for a thousand miles 638 00:32:46,560 --> 00:32:47,480 Speaker 2: before you get to the name. 639 00:32:48,280 --> 00:32:49,800 Speaker 1: It might be the BUCkies of space. 640 00:32:50,400 --> 00:32:52,720 Speaker 2: Yes, the moon is, but we've only got one. 641 00:32:53,800 --> 00:32:55,920 Speaker 1: Well, the buggies are really hard to find too, aren't they. 642 00:32:56,600 --> 00:32:56,800 Speaker 2: Yeah? 643 00:32:56,880 --> 00:33:02,320 Speaker 1: Yeah, all right, last question, Matt. When you step out 644 00:33:02,360 --> 00:33:04,960 Speaker 1: in a warm Hawaiian night you see the full moon, 645 00:33:05,200 --> 00:33:05,960 Speaker 1: what are you thinking that? 646 00:33:07,400 --> 00:33:10,680 Speaker 2: Well, just last night, I think we're out and I 647 00:33:10,720 --> 00:33:12,800 Speaker 2: saw the moon with my kids, and I said, you know, 648 00:33:13,080 --> 00:33:15,479 Speaker 2: in a couple of weeks, there's going to be people 649 00:33:15,800 --> 00:33:20,800 Speaker 2: behind that thing, right, And that thought alone is pretty 650 00:33:21,120 --> 00:33:24,840 Speaker 2: neat and exciting. Yeah, that there will be people there, 651 00:33:25,200 --> 00:33:27,840 Speaker 2: and maybe you know, in a few years it will 652 00:33:27,880 --> 00:33:29,520 Speaker 2: be all of us, right, a lot of us going 653 00:33:30,200 --> 00:33:33,520 Speaker 2: going to this gas station in the sky. Yeah, And 654 00:33:33,560 --> 00:33:36,600 Speaker 2: it's just neat to look at the Moon and knowing 655 00:33:36,640 --> 00:33:39,760 Speaker 2: about some of this history, of all the processes that 656 00:33:39,800 --> 00:33:42,400 Speaker 2: happened on the Moon, from the delivery of ice to 657 00:33:42,600 --> 00:33:45,040 Speaker 2: volcanoes on the surface of the Moon. There's a lot 658 00:33:45,080 --> 00:33:47,760 Speaker 2: of exciting stuff that you can imagine going on up there, 659 00:33:47,920 --> 00:33:51,040 Speaker 2: and you can imagine it differently on the moon because 660 00:33:51,080 --> 00:33:53,640 Speaker 2: you can see it. You know, I see Jupiter in 661 00:33:53,640 --> 00:33:56,000 Speaker 2: the night sky, and I can imagine what's going on 662 00:33:56,040 --> 00:33:59,200 Speaker 2: in that dot maybe. But the Moon is somehow this 663 00:33:59,280 --> 00:34:02,960 Speaker 2: thing that we all can relate to because it's still something. 664 00:34:03,040 --> 00:34:04,720 Speaker 2: We can see it from the Earth. 665 00:34:04,920 --> 00:34:06,840 Speaker 1: And it is a part of the Earth, right. 666 00:34:06,920 --> 00:34:10,120 Speaker 2: Yeah, it appears to be part of the Earth and 667 00:34:10,200 --> 00:34:13,160 Speaker 2: part of our formation of the Earth. And we're part 668 00:34:13,200 --> 00:34:15,759 Speaker 2: of the Earth, right We're made of the material from 669 00:34:15,760 --> 00:34:18,080 Speaker 2: the Earth too, So the moon is. 670 00:34:18,000 --> 00:34:22,640 Speaker 3: Our brother, all right. 671 00:34:22,960 --> 00:34:26,520 Speaker 1: So to recap scientists think our moon came from the 672 00:34:26,680 --> 00:34:30,279 Speaker 1: random collision of two small planets. The moon is always 673 00:34:30,320 --> 00:34:32,720 Speaker 1: facing us the same way because it's shaped a little 674 00:34:32,760 --> 00:34:35,759 Speaker 1: like an American football. We're not one hundred percent sure 675 00:34:36,040 --> 00:34:39,279 Speaker 1: what's inside of it. It could still be cheese. And 676 00:34:39,640 --> 00:34:42,240 Speaker 1: the moon might in the future serve as a gas 677 00:34:42,239 --> 00:34:46,040 Speaker 1: station for our exploration of the cosmos. So if all of 678 00:34:46,080 --> 00:34:49,239 Speaker 1: that doesn't turn you into a lunatic, I don't know 679 00:34:49,280 --> 00:34:53,080 Speaker 1: what will. Thanks for joining us. See you next time 680 00:34:56,080 --> 00:34:59,439 Speaker 1: you've been listening to science stuff. Production of Heart Radio 681 00:35:00,280 --> 00:35:03,239 Speaker 1: written and produced by me or Hey Cham, edited by 682 00:35:03,280 --> 00:35:07,200 Speaker 1: Rose Seguda, Executive producer Jerry Rowland, and audio engineer and 683 00:35:07,200 --> 00:35:10,640 Speaker 1: mixer Kasey Pegram, and you can follow me on social media. 684 00:35:10,840 --> 00:35:13,520 Speaker 1: Just search for PhD Comics and the name of your 685 00:35:13,520 --> 00:35:16,440 Speaker 1: favorite platform. Be sure to subscribe to sign stuff on 686 00:35:16,480 --> 00:35:20,279 Speaker 1: the iHeartRadio app, Apple Podcasts or wherever you get your podcasts, 687 00:35:20,360 --> 00:35:23,320 Speaker 1: and please tell your friends we'll be back next Wednesday 688 00:35:23,360 --> 00:35:32,080 Speaker 1: with another episode.