WEBVTT - How Did The Moon Form? 0:00:08.039 --> 0:00:09.639 You know, I look up at the sky at night, 0:00:09.840 --> 0:00:11.959 and one of the most amazing things to stare at 0:00:11.960 --> 0:00:15.240 as the moon, because it just seems so calm and peaceful, 0:00:15.320 --> 0:00:18.040 hanging up there in the sky and looking down at us. Yeah, 0:00:18.160 --> 0:00:22.560 moonlight is so calming, right and reassuring. Yes, especially if 0:00:22.600 --> 0:00:27.360 you're a vampire or a werewolf. I heard that the 0:00:27.440 --> 0:00:33.040 moon actually has this crazy, violent, cataclysmic past. Yeah, that's right, 0:00:33.080 --> 0:00:35.720 hanging up there in the sky acting all common nights. 0:00:35.720 --> 0:00:37.760 It turns out it may have been party to one 0:00:37.760 --> 0:00:40.080 of the greatest murder mysteries in the history of the 0:00:40.120 --> 0:00:45.599 Solar system, a very impactful event, that's right. And I 0:00:45.680 --> 0:00:48.559 love when there are things hanging out right there on 0:00:48.600 --> 0:00:52.080 our faces that give us clues as to great drama 0:00:52.280 --> 0:01:12.800 that took place in deep dark history. Hi. I'm Jorge. 0:01:12.840 --> 0:01:16.000 I'm a cartoonist, and I'm Daniel. I'm a particle physicist, 0:01:16.200 --> 0:01:18.920 And welcome to our podcast. Daniel and Jorge explained the 0:01:19.000 --> 0:01:21.400 universe in which we look around at anything in the 0:01:21.480 --> 0:01:25.200 universe and try to explain it to you. On today's program, 0:01:25.319 --> 0:01:31.080 that big white, shiny thing in the night sky, the 0:01:31.160 --> 0:01:34.319 thing you referred to as the moon, not any moon, 0:01:34.880 --> 0:01:39.080 Not a moon, The moon, the moon earth little sidekick. 0:01:39.720 --> 0:01:42.679 That's right. And if you're a person who wonders and 0:01:42.720 --> 0:01:45.440 thinks about the history of things, you like all of 0:01:45.520 --> 0:01:47.720 humanity must have looked up in the night sky wondered 0:01:47.760 --> 0:01:49.800 what are the stars? Where do they come from? But 0:01:49.880 --> 0:01:52.120 the biggest thing, the fattest thing out there in the 0:01:52.240 --> 0:01:54.760 night sky is the moon. And what a mystery that 0:01:54.840 --> 0:01:57.640 must have presented to ancient man and woman. Right, what 0:01:57.760 --> 0:02:01.280 is that giant disk and where did it come from? 0:02:01.360 --> 0:02:04.240 That's right, And that's a question that science is still 0:02:04.280 --> 0:02:07.040 trying to answer. We've gone to the moon, We've looked 0:02:07.040 --> 0:02:10.000 at the moon with crazy telescopes, people have walked across 0:02:10.000 --> 0:02:12.320 it and brought samples back. But we still don't know 0:02:12.360 --> 0:02:15.440 the answer to the question how did the Earth get 0:02:15.520 --> 0:02:18.200 its moon. That's a crazy idea to me that we 0:02:18.240 --> 0:02:20.800 don't know where the moon came from, you know, like 0:02:20.919 --> 0:02:23.600 we it could have just appeared out of door one day, 0:02:24.240 --> 0:02:26.920 or aliens could have dropped it off. Oh that's an 0:02:26.960 --> 0:02:29.000 option I haven't heard yet that like somebody opened a 0:02:29.040 --> 0:02:32.000 wormhole in the moon just look popped, there's a moon 0:02:32.160 --> 0:02:35.320 all of a sudden. That's an awesome idea. Yeah, how 0:02:35.320 --> 0:02:38.359 does something that big just come about right, so perfectly 0:02:38.480 --> 0:02:42.960 round and pretty smooth and bright. Yeah, but it turns 0:02:42.960 --> 0:02:45.240 out the Earth's moon is not like the other moon's. 0:02:45.280 --> 0:02:47.200 You know, one of these things is not like the 0:02:47.240 --> 0:02:49.920 other things, and the moon is kind of weird, which 0:02:49.919 --> 0:02:52.720 makes it hard to explain. Yeah, it's a weird moon. 0:02:53.960 --> 0:02:55.280 It's the only one we have, and so for a 0:02:55.280 --> 0:02:58.440 long time it's sort of defined the whole concept of moon. Right, 0:02:58.840 --> 0:03:00.839 But now that we've seen other planet and we've seen 0:03:00.840 --> 0:03:03.320 how many little moons they have, were like, jeez, our 0:03:03.360 --> 0:03:05.080 moon is kind of weird. Does my moon make me 0:03:05.120 --> 0:03:08.320 look fat? You know, because we've got a big, fat moon. Yeah. 0:03:08.440 --> 0:03:11.040 So this is an interesting question, and we wondered how 0:03:11.080 --> 0:03:13.520 many of you out there no or think they know 0:03:13.600 --> 0:03:16.480 the answer to the question where did the moon come from? 0:03:16.760 --> 0:03:19.440 So I walked around the campus of UC Irvine and 0:03:19.480 --> 0:03:22.240 accosted random strangers who are willing to talk to me 0:03:22.280 --> 0:03:24.760 and asked them this question, where do you think the 0:03:24.840 --> 0:03:27.440 moon came from? Yeah, so before you listen to these answers, 0:03:27.520 --> 0:03:31.000 think for yourself what would be your best guess. Here's 0:03:31.040 --> 0:03:33.760 what people have to say. I'm not entirely certain. I 0:03:33.800 --> 0:03:36.920 just know gravity plays a part in it. There was 0:03:36.960 --> 0:03:38.840 like a meteorite that hit the Earth which broke off 0:03:38.880 --> 0:03:41.000 some rocks or something like that. From what I remember, 0:03:41.200 --> 0:03:43.640 it might be that, well this is like the big Thing, 0:03:43.800 --> 0:03:49.200 but I don't really know, no, No, My best guess 0:03:49.360 --> 0:03:53.080 is that it either came from some sort of material 0:03:53.200 --> 0:03:59.640 that was already in the atmosphere and by some sort 0:03:59.680 --> 0:04:03.320 of a potational pull was brought in. Alright, So not 0:04:03.440 --> 0:04:06.840 a lot of strong ideas here. I think it's a 0:04:06.920 --> 0:04:09.760 pretty there's a good breath of ideas. Yeah. I like 0:04:09.800 --> 0:04:11.560 the people who answer where did the moon come from? 0:04:11.800 --> 0:04:16.560 And they would just say gravity, Like that's the answer too, 0:04:16.600 --> 0:04:20.320 pretty much everything there, or the or someone said the 0:04:20.400 --> 0:04:23.400 Big Bang. I'm like, yeah, of course everything came from 0:04:23.440 --> 0:04:26.360 the Big Bang. That is that is a good default 0:04:26.360 --> 0:04:28.320 physics answer that somebody asked you a physics question. The 0:04:28.320 --> 0:04:31.000 answer is always the Big Bang. How does the hig 0:04:31.040 --> 0:04:35.000 boson give mass to other particles? It's the Big Bang? Really, 0:04:35.120 --> 0:04:37.760 you can't go wrong. So could have see that person 0:04:37.839 --> 0:04:44.280 on the street figured out how to always be right? Well, 0:04:44.360 --> 0:04:46.919 let's talk about the moon. How big is the moon? Daniel? 0:04:47.200 --> 0:04:50.159 Or let's maybe take a step back. What is the moon? Right, 0:04:50.200 --> 0:04:52.800 So it's just a definitional thing, right. You have solar 0:04:52.839 --> 0:04:55.440 systems that have these hierarchies. You almost always have the 0:04:55.480 --> 0:04:58.520 main masses in the center. You have star where most 0:04:58.520 --> 0:05:01.080 of this has gathered, and then you have the planets 0:05:01.360 --> 0:05:03.080 orbiting around it. And then you know, you have need 0:05:03.080 --> 0:05:05.520 a name for the stuff orbiting around the planets. The 0:05:05.640 --> 0:05:07.440 theory this could go on forever. Right, you have the 0:05:07.440 --> 0:05:10.719 star with planets around it, and then moons around the planets, 0:05:10.800 --> 0:05:12.640 and then you can have things orbiting around the moon, 0:05:13.120 --> 0:05:16.120 and then things orbiting around those things, like moons can 0:05:16.200 --> 0:05:18.960 have moonies. Yeah, I think they're called moonlits moon or 0:05:19.040 --> 0:05:23.960 moon ETOs or something. Yeah. So so it's just it's 0:05:24.040 --> 0:05:29.039 just the name given to something floating around a planet. Yeah, exactly. 0:05:29.080 --> 0:05:30.960 If you're a blob of stuff floating around the planet, 0:05:31.000 --> 0:05:33.000 then we call you a moon. But it's interesting because 0:05:33.000 --> 0:05:34.880 you've got to be big enough, right, Like, if you're 0:05:34.920 --> 0:05:37.480 just specks of stuff, then we call you a ring. Right, 0:05:37.480 --> 0:05:39.560 if you're like distributed all the way around the planet, 0:05:39.680 --> 0:05:42.240 then we got then you've got rings, Like Saturn has rings. 0:05:42.400 --> 0:05:46.160 Saturn's got rings Jupiter's got rings, you know. Um, and 0:05:46.480 --> 0:05:48.760 it's in some ways a question of definition, Like there 0:05:48.839 --> 0:05:51.240 is stuff floating around the Earth into sort of a vague, 0:05:51.360 --> 0:05:53.560 hazy rings. So could you say the Earth has rings? 0:05:53.680 --> 0:05:55.640 You know, people argue about that kind of stuff, but 0:05:55.640 --> 0:05:57.800 that's just like that's arguing about the definition. It's not 0:05:57.839 --> 0:06:00.080 really arguing about the science generally. But it has it 0:06:00.120 --> 0:06:03.000 has to have a certain size to be called a moon, 0:06:03.360 --> 0:06:07.920 I think, so, yeah, otherwise it's just a rock rock 0:06:08.360 --> 0:06:12.360 rock or rock let or rocky rocky dough. Yeah, there 0:06:12.440 --> 0:06:15.560 must be some organization out there that's tasked with classifying 0:06:15.600 --> 0:06:17.560 what the moon and what's the moonlit, and what's just 0:06:17.600 --> 0:06:20.480 a piece of ring and with just random garbage in space. 0:06:20.600 --> 0:06:23.680 You know. Um, that doesn't sound a very glamorous job. 0:06:24.080 --> 0:06:26.520 So how big is our moon? Our Our moon is 0:06:26.600 --> 0:06:30.680 really big. Our moon is two thousand miles across, which 0:06:30.720 --> 0:06:32.400 is pretty big compared to the Earth, which you know, 0:06:32.520 --> 0:06:35.280 is only eight thousand miles across, and most of the 0:06:35.320 --> 0:06:38.039 other planets their moons are tiny in comparison to the 0:06:38.080 --> 0:06:40.000 size of the planet. So it's pretty big. So it's 0:06:40.040 --> 0:06:44.440 like from California to about like Arkansas or something, you're 0:06:44.480 --> 0:06:46.200 giving me the worries here, Like if you took the 0:06:46.240 --> 0:06:48.600 Moon and sort of gently put it down, how far 0:06:48.680 --> 0:06:51.960 would it would it look? Like? Why do you even 0:06:52.000 --> 0:06:54.720 imagine that? Like placing the Moon on the Earth just 0:06:54.760 --> 0:06:57.000 for scale, you know, like you were to walk across 0:06:57.000 --> 0:07:00.280 the Moon, how long would it take you? You know? Right? Yeah, um, 0:07:00.279 --> 0:07:01.920 well not that long because you could bounce because of 0:07:01.920 --> 0:07:04.360 the gravity is pretty low. But yeah, it's like two 0:07:04.440 --> 0:07:06.480 thousand miles, so it's not as far as l A 0:07:06.560 --> 0:07:08.680 to New York, for example. But it's pretty big, right, 0:07:08.680 --> 0:07:10.760 It's pretty big. And the interesting thing is that it's 0:07:10.800 --> 0:07:15.119 at the same scale as other planets in the Solar System. Okay, 0:07:15.120 --> 0:07:17.160 so I looked it up, uh, and I did some 0:07:17.240 --> 0:07:20.000 quick calculations because I'm a train engineer and I can 0:07:20.280 --> 0:07:24.000 do some math here, and so like if the Earth 0:07:24.080 --> 0:07:26.520 was the size of a basketball, the Moon would be 0:07:26.800 --> 0:07:29.160 a little bit under the size of a tennis ball. 0:07:29.280 --> 0:07:32.160 I prefer I preferred fruit based analogy. So I'm gonna 0:07:32.160 --> 0:07:35.320 go with a watermelon and an apple. Watermelon, and then 0:07:35.360 --> 0:07:37.560 are you hungry, Daniel? Do we need to take a 0:07:37.640 --> 0:07:40.560 break here and break for a while? A right, as 0:07:40.600 --> 0:07:43.800 a watermelon and an apple. Except what this interesting? The 0:07:43.840 --> 0:07:47.480 distance is maybe a lot larger than most people think. So, 0:07:47.520 --> 0:07:51.120 like you would have to put a watermelon down and 0:07:51.120 --> 0:07:54.240 then walked about twenty five ft and then set down 0:07:54.320 --> 0:07:57.320 that apple. And that's about the distance between the Earth 0:07:57.640 --> 0:08:01.720 and the Moon. Yeah, it's crazy. These things seem big, 0:08:01.720 --> 0:08:04.280 but they're tiny compared to the distances between them, right, 0:08:04.320 --> 0:08:07.480 which is sort of a larger lesson for everything in space, right, 0:08:07.480 --> 0:08:09.840 Like the Sun and the Earth seem huge, but they're 0:08:09.920 --> 0:08:13.040 really far apart compared to their diameters. And our solar 0:08:13.080 --> 0:08:15.720 system is far from the next star and and it's 0:08:15.760 --> 0:08:19.040 incredible the distances between stuff and space. Yeah, okay, so 0:08:19.080 --> 0:08:22.360 that's the moon. Um. The crazy thing is that we 0:08:22.360 --> 0:08:24.679 don't know where the moon came from. That's right. People 0:08:24.680 --> 0:08:27.000 have been trying to figure out how do you get 0:08:27.000 --> 0:08:30.400 the Moon this big and this weird around the planet 0:08:30.520 --> 0:08:33.200 this close to the Sun, and they can't figure it out. 0:08:33.280 --> 0:08:35.120 You know, they have simulations and theories, and you know, 0:08:35.160 --> 0:08:37.600 this is what scientists do. They say, can we explain 0:08:37.640 --> 0:08:39.720 what we see? And they start with an idea and 0:08:39.760 --> 0:08:42.200 they see does that work? Right? Can I take that 0:08:42.280 --> 0:08:44.520 idea and end up with the situation I see in 0:08:44.559 --> 0:08:47.160 front of me, and they have some ideas, and we'll 0:08:47.160 --> 0:08:49.439 talk about them, we'll dig into them. But the bottom 0:08:49.440 --> 0:08:51.480 line is that none of the ideas we currently have 0:08:51.720 --> 0:08:55.160 completely work. They all have problems, which suggests that the 0:08:55.200 --> 0:08:57.280 answer is something we haven't yet thought of, or some 0:08:57.360 --> 0:09:01.000 weird twist on one of the current ideas. All right, 0:09:01.080 --> 0:09:03.360 bring it down for us. How what are the different 0:09:03.360 --> 0:09:06.120 ways that a planet can get a moon? Like? If 0:09:06.120 --> 0:09:08.320 I wanted a moon, what would I need to do? 0:09:08.360 --> 0:09:10.600 You just go on Amazon, man, you can order anything. Well, 0:09:10.720 --> 0:09:13.040 you can probably get a moon. Tomort. You want a moon, 0:09:13.160 --> 0:09:15.040 I get you a moon by tomorrow afternoon. That's what 0:09:15.080 --> 0:09:16.920 Walter from the Big Labowski would saying. Can I just 0:09:16.960 --> 0:09:19.320 get a slightly a shorter person to just follow me 0:09:19.360 --> 0:09:23.880 around and turn around me? That's not a moon, that 0:09:23.880 --> 0:09:27.200 that's an assistant. You want somebody in your orbit, right 0:09:27.400 --> 0:09:30.079 who protects you from stuff? Right, cleans out all the 0:09:30.120 --> 0:09:32.440 space junk that's coming at you. Um. Yeah, So how 0:09:32.440 --> 0:09:35.040 does the planet get a moon? Well? One option is 0:09:35.080 --> 0:09:37.360 that it's formed when the planet is formed. Right, Let's 0:09:37.360 --> 0:09:40.199 remember how our planets formed, and it's um not from 0:09:40.200 --> 0:09:43.720 the Big Bang, right, Like our professional physicist from earlier. Directly, 0:09:43.760 --> 0:09:46.760 it is from gravity though, So you're saying that the 0:09:47.120 --> 0:09:49.560 planet can get a moon at the same time that 0:09:49.640 --> 0:09:52.760 it's forming, kind of like a little twin brother. Yeah, exactly. 0:09:52.760 --> 0:09:54.840 So imagine how is the planet formed. Well, it starts 0:09:54.840 --> 0:09:57.200 from a big poof of gas and dust and rocks, right, 0:09:57.200 --> 0:10:00.800 and then gravity coalesces it together gradually, slowly, slowly into 0:10:00.800 --> 0:10:03.000 a big clump. And you might wonder, why doesn't it 0:10:03.040 --> 0:10:05.280 all form into one big clump, right? Why do you 0:10:05.280 --> 0:10:09.040 get little bits left over as moons or other stuff? Um? 0:10:09.080 --> 0:10:10.960 And this sort of two answers to that, like most 0:10:10.960 --> 0:10:13.199 of it goes into the big clump. Right. First of all, 0:10:13.360 --> 0:10:15.800 like most of the stuff goes into the planet. Um. 0:10:15.960 --> 0:10:17.600 The reason it doesn't all is that some of it's 0:10:17.640 --> 0:10:21.040 traveling really fast, and so rather than getting pulled down 0:10:21.120 --> 0:10:23.679 into the central clump, essentially ends up in orbit. Right. 0:10:24.040 --> 0:10:26.320 So what we call in physics, we call it angular momentum. 0:10:26.360 --> 0:10:28.760 Supported you know, it's the reason that the Earth doesn't 0:10:28.800 --> 0:10:32.080 just fall into the Sun. Right, It's because it's moving fast. Oh. 0:10:32.280 --> 0:10:34.320 I see, So there's a bunch of stuff that came together, 0:10:34.520 --> 0:10:37.040 But some of that stuff was a little bit out 0:10:37.040 --> 0:10:40.240 on the periphery and didn't quite make it into the 0:10:40.280 --> 0:10:43.520 main planet clump exactly. And it's all spinning, right, the 0:10:43.520 --> 0:10:46.120 whole thing is spinning and it's going and so it 0:10:46.200 --> 0:10:48.960 starts out spinning around and it's moving too fast to 0:10:48.960 --> 0:10:51.520 get sucked in. Um. And the other part of the 0:10:51.559 --> 0:10:53.880 story is that none of this happens in isolation, right. 0:10:53.920 --> 0:10:56.040 The Earth is not in the middle of totally empty 0:10:56.080 --> 0:10:59.079 space forming quietly. This stuff going on all the time, 0:10:59.120 --> 0:11:01.240 And in the early soul or system, we think things 0:11:01.240 --> 0:11:04.200 were pretty crazy and so um. It might have been 0:11:04.240 --> 0:11:06.000 that the early blob that formed the Earth could have 0:11:06.080 --> 0:11:07.959 formed a single planet with no moon and no other 0:11:08.000 --> 0:11:10.520 objects or whatever. But it probably got perturbed a lot, 0:11:10.559 --> 0:11:13.000 you know, things crash into it, things bump into it. 0:11:13.080 --> 0:11:15.280 Even just the tugging of the Sun and other planets 0:11:15.280 --> 0:11:18.040 coming nearby keep that stuff from really settling, and so 0:11:18.080 --> 0:11:20.800 some of it ends up still out in space opening 0:11:20.840 --> 0:11:23.760 around the planet. Okay, it formed at the same time 0:11:23.800 --> 0:11:26.959 as the planet. Yeah, that happens in some cases, we think, um, 0:11:26.960 --> 0:11:28.800 so sorry it's too late for you there. Or if 0:11:28.800 --> 0:11:31.160 you wanted a moon from the from zero, you've missed 0:11:31.160 --> 0:11:34.240 your window. I need to go back to the to 0:11:34.320 --> 0:11:39.680 the womb. That's right, the womb moon the moon. That's 0:11:39.720 --> 0:11:43.000 a that's a tongue twist right there. Um yeah. But 0:11:43.040 --> 0:11:45.240 the better way, I think, the more popular way the 0:11:45.280 --> 0:11:48.120 planets gives moves. All the cool planet at least get 0:11:48.200 --> 0:11:52.360 moons by basically interacting with other objects. You know, like, um, 0:11:52.480 --> 0:11:55.360 something smashes into them, or something flies by and they 0:11:55.440 --> 0:11:58.560 capture it. Um, that kind of stuff. Wait wait wait wait, um, 0:11:58.600 --> 0:12:01.560 so those are two other things. You can either capture 0:12:01.720 --> 0:12:04.560 a moon, Like if the Earth was flying around and 0:12:04.600 --> 0:12:06.600 suddenly there was a little bit of rock out there, 0:12:06.640 --> 0:12:09.160 it would it could like bring it into its orbit. 0:12:09.480 --> 0:12:11.760 It could bring it into its orbit. That's not very 0:12:11.800 --> 0:12:15.280 easy to do because much more likely is that something 0:12:15.320 --> 0:12:18.440 comes and smashes into the Earth and then the resulting 0:12:18.480 --> 0:12:23.199 debris floats up into space and then turns into a 0:12:23.240 --> 0:12:26.439 system of rings and then coalesces into a moon. That's 0:12:26.520 --> 0:12:29.959 much more likely. It's because it's hard to capture something entirely. 0:12:30.280 --> 0:12:33.520 Either it deflects right, it bounces off into space, or 0:12:33.520 --> 0:12:36.080 it hits the Earth getting captured. It means you have 0:12:36.120 --> 0:12:38.440 to be exactly the right speed at exactly the right 0:12:38.480 --> 0:12:41.199 angle at exactly the right orbit. It's a difficult thing 0:12:41.200 --> 0:12:43.600 to do. It's like getting a perfect pool shot, you know, 0:12:44.080 --> 0:12:46.559 jumping the eight ball or something. You're saying, that's harder 0:12:46.600 --> 0:12:49.720 than getting hit by something out in space. Yeah, because 0:12:49.720 --> 0:12:51.800 the Earth has gravity, right, So if something comes close by, 0:12:51.840 --> 0:12:53.800 it's most likely just going to spiral in and smash 0:12:53.880 --> 0:12:56.760 into the Earth, or it's going to bounce off into flect. 0:12:56.840 --> 0:12:58.920 So coming in from somewhere else and then ending up 0:12:58.920 --> 0:13:01.160 in orbit is pretty trick. Okay, So I think the 0:13:01.200 --> 0:13:04.040 most likely way to get a moon is for something 0:13:04.040 --> 0:13:06.680 to smash into the planet and the debris to float 0:13:06.760 --> 0:13:10.480 up and then coalesce into a moon. Alright, let's get 0:13:10.559 --> 0:13:14.120 into this smashing idea, but first let's take a quick break. 0:13:27.080 --> 0:13:28.800 All right. So you're saying that one way to get 0:13:28.800 --> 0:13:31.160 a moon, and maybe our moon came this way, is 0:13:31.160 --> 0:13:34.920 that something smashed into the Earth and kind of like 0:13:35.200 --> 0:13:38.600 broke off a piece that then became the moon. That's right, Yeah, 0:13:38.679 --> 0:13:40.240 And that's a that's the way we think some of 0:13:40.280 --> 0:13:43.600 the moon's have occurred in the Solar System. But it's 0:13:43.960 --> 0:13:48.920 tricky to explain our moon, right, Um, and because our 0:13:48.960 --> 0:13:52.360 moon is so big, right, Our moon is huge compared 0:13:52.400 --> 0:13:54.960 to the planet, and so in order to make that 0:13:55.160 --> 0:13:58.320 size the Moon work, you need a huge impact, right, 0:13:58.320 --> 0:14:00.480 You need a ridiculously big effact. You can't just be 0:14:00.559 --> 0:14:03.000 hit by laroc that knocks off a bunch of stuff. 0:14:03.160 --> 0:14:07.640 You need a giant impact, like a planet killing impact. Yeah. 0:14:07.679 --> 0:14:10.679 And the current models say that the kind of thing 0:14:10.720 --> 0:14:12.680 that hit the Earth a long long time ago to 0:14:12.720 --> 0:14:15.000 make the Moon might have been something the size of 0:14:15.000 --> 0:14:16.800 a planet. It might have been a proto planet, might 0:14:16.840 --> 0:14:19.240 have been something the size of Mars. Right, So we're 0:14:19.280 --> 0:14:22.880 talking about like two planets colliding, right, This must have 0:14:22.920 --> 0:14:26.240 been amazing to watch, right, right or not if you're 0:14:26.280 --> 0:14:29.960 living in these planets, that's right. Well, we don't think 0:14:30.000 --> 0:14:31.760 there was anything alive on Earth when it happened. The 0:14:31.760 --> 0:14:35.320 best estimates say that this happened about um zero point 0:14:35.400 --> 0:14:38.280 one billion years or a hundred million years after the 0:14:38.280 --> 0:14:41.120 Earth was formed, So the Earth was still pretty hot 0:14:41.560 --> 0:14:44.240 and a nasty when this kind of stuff happened. We 0:14:44.280 --> 0:14:47.400 don't think there was any atmosphere of life yet collided 0:14:47.640 --> 0:14:51.960 with another planet about its size. That's incredible, right, two 0:14:52.040 --> 0:14:57.320 giant balls of rock just yeah, exactly, and um and 0:14:57.400 --> 0:14:59.960 that must have been pretty kindaclasmic, right, A lot of 0:15:00.000 --> 0:15:03.120 stuff must have gotten thrown off into space, and some 0:15:03.200 --> 0:15:06.320 of that stuff coalesced into rings. So the Earth probably 0:15:06.360 --> 0:15:09.400 had rings for a while, no way like Saturn. Yeah, 0:15:09.480 --> 0:15:11.320 I know that has been pretty awesome, right, I kind 0:15:11.320 --> 0:15:12.880 of wish the Earth had rings, Like what would that 0:15:12.880 --> 0:15:15.000 look like at night or during the day, you know, 0:15:15.120 --> 0:15:17.080 to see rings up in the sky. That would be 0:15:17.080 --> 0:15:20.480 pretty incredible. So then the two planets collected is the 0:15:20.520 --> 0:15:23.600 idea to planets collided, they form a new Earth with 0:15:23.760 --> 0:15:27.680 some stuff out there in rings that eventually became the Moon. 0:15:28.000 --> 0:15:30.080 That's right. And this collision was huge, right, It was 0:15:30.160 --> 0:15:33.760 like a hundred million times the energy of the asteroid 0:15:33.760 --> 0:15:36.240 that hit the Earth and probably killed the dinosaurs. So 0:15:36.320 --> 0:15:40.800 it's a ginormous explosion. It's nothing that anybody could ever survive. Yeah, 0:15:40.840 --> 0:15:43.000 I've seen I've seen the videos of the stimulations. Like 0:15:43.040 --> 0:15:46.600 it's basically the Earth just gets pulverized and then just 0:15:46.720 --> 0:15:49.680 kind of coagulates into this new thing. But it's like 0:15:49.720 --> 0:15:52.640 it's basically obliterated. Yeah, and here you'll see the strength 0:15:52.680 --> 0:15:55.560 of my fruit based analogy, which is imagined you take 0:15:55.560 --> 0:15:58.040 two watermelons and you throw them together. What happens, right, 0:15:58.120 --> 0:16:01.560 that's pretty much what's happened. You know, it's complete destruction. 0:16:01.720 --> 0:16:08.280 The watermelons do not survive that kind of impact. So 0:16:08.320 --> 0:16:11.960 then how do rings become moons? And why? Like, why 0:16:12.000 --> 0:16:14.600 does Saturn still have rings and nut moons? Yeah, that's 0:16:14.600 --> 0:16:17.360 a really awesome question because gravity, right, you would think 0:16:17.440 --> 0:16:20.240 if stuff is floating out there in space, then eventually 0:16:20.320 --> 0:16:22.880 gravity would coalesce, it would pull it all together into 0:16:22.880 --> 0:16:25.800 a moon. And that does happen if you're far enough 0:16:25.840 --> 0:16:29.000 away from the planet. If you're too close to the planet, 0:16:29.360 --> 0:16:31.600 then the strength of gravity tugging on you from one 0:16:31.640 --> 0:16:33.640 side and the strength of gravity tugging you from the 0:16:33.640 --> 0:16:36.600 other side are too different. Because remember the force of 0:16:36.600 --> 0:16:39.440 gravity depends on your distance from an object, and so 0:16:39.480 --> 0:16:41.640 one side of the Moon is closer to the Earth 0:16:41.680 --> 0:16:44.280 than the other side of the Moon, So the Earth 0:16:44.400 --> 0:16:46.720 pulls on one side of the Moon more than the 0:16:46.720 --> 0:16:49.560 other side, So it's literally pulling the Moon apart. But 0:16:49.600 --> 0:16:51.680 the Moon is far enough away from the Earth that 0:16:51.760 --> 0:16:54.320 the Earth is not strong enough to shred the Moon. 0:16:54.960 --> 0:16:58.160 But if the Moon was a lot closer right then 0:16:58.160 --> 0:17:00.960 it then it would be pulled apart. By these gravitational 0:17:01.000 --> 0:17:04.600 they're called tidal forces. By the tidal forces, so there's 0:17:04.600 --> 0:17:06.840 a region around every planet where you just cannot be 0:17:06.920 --> 0:17:09.879 a moon because if you are, you're gonna get shredded, right, 0:17:10.400 --> 0:17:12.560 So you just kind of get ripped apart. Yeah, it's 0:17:12.600 --> 0:17:16.320 like a blender. There is like a blender. Yeah, and 0:17:16.359 --> 0:17:19.040 we've seen this happen if you remember the comment that 0:17:19.119 --> 0:17:22.480 hit Jupiter um in the nineties. It passed really close 0:17:22.480 --> 0:17:24.879 by Jupiter before it hit and Jupiter pulled it apart 0:17:24.920 --> 0:17:28.119 into twenty six pieces because of his tidal forces. And 0:17:28.119 --> 0:17:30.480 so the larger the planet, the stronger the force of gravity, 0:17:30.760 --> 0:17:33.160 and the more likely this is to happen. Oh I see. 0:17:33.760 --> 0:17:36.440 So if Saturn had bigger rings or rings that were 0:17:36.480 --> 0:17:40.199 further apart, then the tidal forces would be less and 0:17:40.200 --> 0:17:42.919 then the little bits of it would have time when 0:17:43.400 --> 0:17:47.800 and kind of space to clump together. Yeah, but that's 0:17:47.800 --> 0:17:50.760 a whole other fascinating mystery, like how long has Saturn 0:17:50.800 --> 0:17:53.360 hand rings? How long will it continue to have rings? Right? 0:17:53.600 --> 0:17:56.560 We think that those rings are pretty stable because they 0:17:56.560 --> 0:18:00.000 have been there for like a hundred million years and um, 0:18:00.000 --> 0:18:02.639 and because Saturn has really strong title forces. So anything 0:18:02.680 --> 0:18:05.160 that coalesces, Saturn will tear up again, but we don't 0:18:05.160 --> 0:18:07.720 really know for sure. And Saturn does have some moons, 0:18:07.720 --> 0:18:09.159 and we don't know like are those moons in the 0:18:09.160 --> 0:18:11.680 process of being trashed, Like if you fast forwarded a 0:18:11.760 --> 0:18:13.840 billion years with Saturn look totally different or is it 0:18:13.880 --> 0:18:16.320 looked this way for a long time. It's amazing to 0:18:16.400 --> 0:18:18.760 me how dynamic the Solar system is. You know, like 0:18:18.880 --> 0:18:20.439 if you look at a picture of the Solar System 0:18:20.480 --> 0:18:23.439 from two billion years ago, you might not recognize it. 0:18:23.440 --> 0:18:25.439 You could have a different number of planets, and all 0:18:25.480 --> 0:18:27.040 the planets could have different number of moons, or the 0:18:27.040 --> 0:18:29.719 planets could even be in a different order. It's crazy 0:18:29.760 --> 0:18:32.040 stuff that's happened in our Solar system. Or even two 0:18:32.040 --> 0:18:34.919 billion years from now, it might look totally different. Yeah, well, 0:18:34.920 --> 0:18:36.600 in two billion years from now, I hope we've built 0:18:36.880 --> 0:18:40.879 massive interstellar structures so we're recognizable from space. Um. But 0:18:41.040 --> 0:18:44.480 even without that, Yeah, the planets could reorganize or realign, 0:18:44.640 --> 0:18:46.200 or things could drift this way or the other way, 0:18:46.280 --> 0:18:48.520 or something could come from another Solar system and knock 0:18:48.760 --> 0:18:51.760 knock into something and change everything. Yeah, you know, people 0:18:51.840 --> 0:18:54.480 might imagine the Solar system is really static because it's old, 0:18:55.040 --> 0:18:57.159 but we've only seen the recent history of it. And 0:18:57.400 --> 0:18:59.280 one of the best ways to figure out what is 0:18:59.320 --> 0:19:01.240 the history, what is the whole story here, what is 0:19:01.280 --> 0:19:04.240 the drama that's taking place out there in space, is 0:19:04.280 --> 0:19:06.399 to ask these questions, you know, like how did the 0:19:06.400 --> 0:19:10.000 moon form? Yeah, so that's one possibility, is that something 0:19:10.040 --> 0:19:12.680 smashed into the Earth through all this stuff out there 0:19:12.840 --> 0:19:15.600 that became a moon because it was far enough away 0:19:15.600 --> 0:19:19.440 from the Earth. But there's some that's not quite right, right, 0:19:19.680 --> 0:19:22.280 Like that doesn't quite fit what we see or know 0:19:22.400 --> 0:19:25.760 about the moon. Yeah, it's interesting because we can't quite 0:19:25.920 --> 0:19:29.480 make that story explain everything we see. And so one 0:19:29.520 --> 0:19:31.160 of the things we see, for example, is that we've 0:19:31.200 --> 0:19:33.520 been to the moon and we've looked at rocks from 0:19:33.520 --> 0:19:36.760 the moon. You've been to the moon. I mean we 0:19:36.960 --> 0:19:40.840 collectively as humanity. I like to take credit for humanities 0:19:41.640 --> 0:19:46.000 of humanities collective. The Royal week there. Okay, we have 0:19:46.119 --> 0:19:48.640 won a bunch of NBA championships, by which I mean 0:19:48.800 --> 0:19:53.720 me and Lebron James. Yeah, we are an acclaimed internet cartoonist. 0:19:53.960 --> 0:19:57.280 But which I mean me and you. We are Tom Cruise. 0:19:57.960 --> 0:20:02.399 You know, we are sexy in our fifties exactly. Humanity, 0:20:02.520 --> 0:20:04.520 not me personally, has been to the Moon and brought 0:20:04.520 --> 0:20:06.760 back rocks, and we've looked at those rocks, and those 0:20:06.840 --> 0:20:09.639 rocks look really similar to rocks on Earth. And you 0:20:09.640 --> 0:20:12.000