How to Build a Planet (Using Only 4 Ingredients)

[00:00:07]The Earth, third rock from the sun, and it's unique.

[00:00:17]It has [music] life.

[00:00:21]So, how do you make a planet like ours?

[00:00:27]We are going to open up the cosmic toolbox and work it out.

[00:00:33]We're going to build a planet up there at the top of this impossibly high tower. A platform to build something really big.

[00:00:50]And every construction project needs a foreman.

[00:00:54]So, with the help of our planetary engineer, we're going to start with a cloud of dust and gas and then build our planet brick by brick.

[00:01:19]We'll get help in [music] unexpected ways.

[00:01:25]Oh my god, it's beautiful.

[00:01:32]>> We're going to travel the world.

[00:01:34]>> The rocks actually flowed like water >> and to [music] the edge of space.

[00:01:42]>> We've turned off gravity. We're weightless.

[00:01:45]>> That's how our planet started.

[00:01:48]Of course, as with any building work, there will be hiccups.

[00:01:58]But out of these mistakes will come real insights into what [music] makes our planet exactly right for us, for life.

[00:02:09]As an engineering challenge, it doesn't get much bigger.

[00:02:35]As far as we know, our Earth is the only planet in the solar system with life.

[00:02:45]To understand why, we're going to have to build our own planet at the top of this tower.

[00:03:01]With the help of the planetary engineer, he's going to manage the construction for us.

[00:03:13]The first thing needed are the basic raw materials.

[00:03:17]>> All right. All right.

[00:03:23]>> All the big ingredients to start making a planet.

[00:03:29]Here's the delivery arriving at the tower right on time.

[00:03:53]The main planetary raw materials have been ordered and in the right proportions, but the delivery has been scaled down a bit.

[00:04:08]Heat. Heat.

[00:04:39]Now, you might think our living earth would be made up of countless different things, but actually it's constructed almost entirely out of four basic ingredients.

[00:04:52]So, that's what our convoy has delivered on these trucks. Girders, iron girders.

[00:05:00]Like most big construction projects, we need a lot of iron.

[00:05:06]Secondly, oxygen.

[00:05:11]Sand that's rich in silicon and magnesium.

[00:05:17]The convoy has brought the elements in [music] exactly the same proportions as we'd find on Earth.

[00:05:24]So there are 15 trucks laden with magnesium because 15% of our planet is made from magnesium.

[00:05:32]There are 16 trucks for the 16% that's silicon. 30 trucks carrying oxygen and a column of 32 trucks with iron girders because almost a third of our planet is made of iron.

[00:05:50]It's incredible to think that just these four ingredients make up 93% of our planet's mass. The rest is elemental seasoning.

[00:06:02]And here's some of the remaining ingredients, including calcium, aluminium, and copper.

[00:06:15]The question now is how does the engineer turn all this into a planet?

[00:06:35]He's going to have to take these basic planetary elements and stick them in a kind of blender at the top of the tower where there's a sky full of room to churn things around.

[00:06:49]Our planet didn't just pop into existence. It started out as a swirling cloud of elemental dust floating in space.

[00:07:01]So that's how the planetary engineer is going to [music] have to start as well.

[00:07:10]4 1/2 billion years ago, before the Earth began to form, this dust and gas was all there was.

[00:07:24]So, how will we get from this cloud around our tower to a planet like the Earth?

[00:07:37]The engineer needs something to bind it all together.

[00:07:45]A sort of cosmic superglue.

[00:08:00]>> [music] >> The best way to find out what this super strong planetary glue is is to discover its power in a weightless environment.

[00:08:16]Dr. Dan Dera is a planetary scientist and this plane offers him something unique.

[00:08:25]It can cancel out the Earth's gravity.

[00:08:31]This means he can simulate the conditions in space where that elemental dust began to make a planet.

[00:08:44]The plane's interior is padded, sort of like a flying asylum.

[00:08:50]That's because within 15 minutes, the passengers are going to experience zero gravity. And those conditions will allow Dan to carry out a fascinating experiment because inside this perspect box is the next step to building a planet.

[00:09:09]So, with this box, we're going to explore some of the very earliest stages of planetary formations, flying weightless conditions. We're going to simulate uh the way the planets formed in in the earliest days as the Earth was first starting to form. Instead of microscopic dust particles, I've got coffee, ordinary coffee.

[00:09:28]>> The plane is now climbing to 34,000 ft.

[00:09:32]Once there, it'll throttle back down to earth in a steep arc, perfectly judged, [music] so that inside everyone is falling at the same rate as the plane drops.

[00:09:46]The result is a few moments of weightlessness.

[00:09:55]Oh, great. Here we go. We've turned off gravity. We're weightless. And we're seeing electrostatic forces. That's how our planet started. Electrostatics clumping this coffee together.

[00:10:06]>> Without the influence of gravity, these coffee grains, [music] like that first cosmic dust, rub together as they float.

[00:10:17]This means individual grains get either negatively or positively charged. And this electrostatic charge means they stick together just like the fledgling particles of the earth. 4 and a half billion years ago.

[00:10:41]>> So around the planet building tower, the engineer has bound together those first clumps of dust. But there is a problem.

[00:10:52]Electrostatic forces are very strong, but are only effective over tiny distances.

[00:10:59]Beyond a certain point, about the size of gravel, the dust stops growing.

[00:11:07]So, the engineers planet building plans have already ground to a halt. With nothing to show for it other than bigger bits of dust, he's going to need another force to grow them more.

[00:11:22]It's time to introduce a little gravity to the situation.

[00:11:36]How then does gravity [music] take those bigger bits of dust and gravel and turn them into rocks or even an entire planet?

[00:11:46]At a concealed underground laboratory, there's a secret device that has the answer.

[00:11:53]Until 2001, this used to be a gold mine.

[00:11:57]Now, it's the cutting edge of scientific research.

[00:12:06]Our goal lies nearly a kilometer and a half straight down.

[00:12:16]At the bottom of this shaft is an instrument that's part of a global gravity research experiment.

[00:12:24]In the tunnels of these the Sanford laboratories, scientists are unraveling the workings of the universe.

[00:12:34]These labs are a bit like the underground lair of a James Bond super villain. Like Dr. No.

[00:12:44]And this is Dr. Gnome.

[00:12:54]Scientists have taken Dr. Gnome all over the world. And wherever he's been, he's been weighed with high precision scales.

[00:13:03]And it's his weight that helps explain how gravity can turn gravel into a planet.

[00:13:13]And here below the Earth's surface, the doctor tips the scales at 330.95 g. To be thorough, he's been weighed at other locations underground.

[00:13:26]And in all of them, we have the same reading.

[00:13:30]A kilometer and a half under the surface, he weighs 330.95 g.

[00:13:38]And now the doctor must travel back to the surface to [music] finish this experiment.

[00:13:43]It's vital he isn't damaged on the way up or picks up any dirt that might interfere with readings.

[00:13:56]Back on the surface, the doctor weighs 331.01 g.

[00:14:04]He's 600th of a gram heavier than he was down below.

[00:14:10]And that weight gain is consistent everywhere on the surface.

[00:14:15]This phenomenon can be explained by gravity.

[00:14:24]Gravity is the universal force that attracts one thing to another.

[00:14:29]When we measure [music] something's weight, we are actually measuring the Earth's gravitational pull.

[00:14:36]So why has the doctor's weight changed?

[00:14:39]Well, it's largely to do with differences in the amount of rock underfoot.

[00:14:46]On the surface, there is a good kilometer more rock beneath Dr. Gnome than when he was in the underground lab, meaning more planetary bulk pulling down on him.

[00:14:59]making for a heavier doctor up here than down below.

[00:15:05]Our experiment shows that the more massive something is, the stronger [music] its gravitational pull.

[00:15:26]If the engineer adds gravity to the swarm of dust, we start to see the larger bits attracting the smaller bits.

[00:15:35]Because they are larger, they have a stronger gravitational pull. The bigger they are, the bigger they get. They start to become rocks, and the larger rocks draw in the smaller ones.

[00:15:51]In space, a rock just a kilometer wide can grow to a near Earth-sized planet in just a few million years. Around the engineers tower, it can be done in seconds.

[00:16:05]This is a huge step forward in building our planet.

[00:16:13]The exciting thing is that even though that process began 4 and a half billion years ago on our Earth, it hasn't finished. Because if you know where to look, you can still see how gravity is shaping our planet even today.

[00:16:40]Out in Arizona's badlands, there's breathtaking evidence of how gravity is still building the Earth.

[00:17:00]This is the Behringer Crater.

[00:17:10]This 1.2 kilometer wide hole is a meteorite impact crater.

[00:17:20]And it's given scientists a unique insight into how planets are built.

[00:17:36]Dr. Matt Genge is an expert on this crater, the scar left by an incredibly violent event.

[00:17:46]So the the main evidence here for how this incredibly incredible structure formed is the strata that we can see on the sides of the crater. Along the top there's a a red layer. It's very prominent all the way along the top of the ridge and below and above are a set of rocks ochre in color that look like exactly the same rock. In fact, they're part of the same layer. And that's evidence that that layer has folded over. The rocks in this crater have flowed out of the crater up into the air and turned over by falling back down to the ground. And so the rocks telling us that this is a meteorite impact.

[00:18:31]The meteorite was just 30 m wide, but the shock wave of its impact would have been powerful enough to knock over a brick wall 40 m away.

[00:18:44]By the time it it fell towards the earth, it gets faster and faster as it falls towards the earth, hits the ground, maybe at 26,000 miles hour. And the energy, the kinetic energy associated with that that speed is so huge, so it's around 2 megat tons that it blew all that material outwards that the rocks actually flowed like water out of the crater.

[00:19:15]And that incredible impact changed this landscape not only by creating this huge crater, but also on a microscopic level.

[00:19:28]So there's a rock here that demonstrates the power of a meteorite impact. So this was really originally a really tough sandstone made out of quartz sand like the sand you find on a beach. But now you can see it's this white color and I can actually powder it. It breaks into pieces because it's been crushed by the impact. The quartz grains have been damaged at an atomic level. The atoms have been torn apart and that's made it go soft and powdery.

[00:20:00]The Behringer Crater is evidence of how gravity builds a planet.

[00:20:07]Because every meteorite that plummets to the ground is drawn in by the Earth's gravitational pull.

[00:20:15]The one that created this crater fell 50,000 years ago, but such strikes have been occurring for the last 4.5 billion years. And meteorite fragments that survive the initial impact can offer a glimpse into the earliest moments of a planet's formation. I've got a a a meteorite with me and this is rather a special meteorite because it's one of the oldest it's probably the oldest piece of rock on Earth. So, it's 4 and a half billion years old and dates back to a time before the planets formed. So, the important thing about this meteorite is it's the starting material.

[00:21:02]It's got just the right magnesium and silicon and oxygen and iron and all important heat producing elements for us to make a planet.

[00:21:20]These relics [music] from our planet's formation are all around us. Not all of them leave such spectacular evidence as the Behringer Crater.

[00:21:29]To the inexperienced eye, meteorites look barely different from terrestrial rock. But if you know what you're looking for, they can turn up anywhere.

[00:21:51]In the last 5 years, a new way of finding those meteorites has [music] been pioneered.

[00:21:57]Analyzing historical weather data from Doppler radar now allows scientists to plot the path of meteorite for falls many years after they occur.

[00:22:09]For meteorite hunters like Jeff Nokin, it's opened up a whole new chapter in their search and study of these rocks from space.

[00:22:23]>> Is that the Sunny Clary team?

[00:22:25]>> Nice to see you again. Jeff's been invited by meteorite hunter Sunonny Clary to his home state of Arizona. 15 years ago, a huge fireball was seen in the sky.

[00:22:37]>> Look, there was a big fireball event in 1998. This was witnessed 15 years ago, Jeff. It was seen from surrounding states. I mean, sonic booms throughout the event. Lit up the whole sky. People came out and looked for meteorites. They found nothing.

[00:22:49]>> Unable to locate it. They were just off a few miles. Now, we have the opportunity to see where they went wrong. I would guarantee there's material here. Almost guarantee it. So, we have >> Thanks to the new method of analyzing radar data, Sunny has been able to narrow down the search to a small 2 km wide corridor.

[00:23:07]>> Can you show me? Yes, I can.

[00:23:09]>> The return.

[00:23:11]>> What have we got here?

[00:23:13]>> I have done I've taken my GPS and marked the heavy concentrations where I think the largest pieces possibly or the main terminus is going to be.

[00:23:21]>> So, this is this is our line of flight.

[00:23:23]>> Correct.

[00:23:24]right over our heads.

[00:23:25]>> Correct.

[00:23:27]>> Exploding along the way. Sonic booms.

[00:23:30]>> This is the only section of flat ground here that's open to us.

[00:23:36]>> Maybe fell here.

[00:23:37]>> The question is, can we find them?

[00:23:40]>> The area that Sonny and Jeff think might yield fragments includes a field in the process of being plowed and some scrubby hills. So, the two of them decide to split forces and meet up at the end of the day.

[00:23:53]>> Right.

[00:23:54]>> What I want to do is possibly head up into the hills and try to see if I can locate a small piece up there. I've got a secret weapon today. We can give it a try. And uh >> You have a secret weapon.

[00:24:03]>> Yeah. What is it?

[00:24:05]>> Well, let me see if he works first. I'll show you. [laughter] >> Let me see if my secret weapon works and then I'll tell you what it is.

[00:24:12]>> All right. All right. Well, I shall look forward with great anticipation to seeing that. And we have our secret weapon on the top of Thunderbird 2 over there.

[00:24:20]>> So, should we take a bet? Who finds the first meteorite or?

[00:24:22]>> Yes. Yes. Cuz I know you love a contest.

[00:24:29]>> Jeff's secret weapon is one of the world's largest metal [music] detectors.

[00:24:34]Useful because most meteorites have a high iron content.

[00:24:39]So, Jeff has used his detector very successfully in the past >> in flat terrain like this. A large metal detector on a sled is ideal. We can cover this whole field in a couple of hours, and it would take us a couple of weeks to walk it with smaller handheld detectors.

[00:25:04]Sunny's secret weapon in the hills to the south is a little bit more low tech.

[00:25:13]This is Bricks, an ex police dog with a trained nose for metal.

[00:25:20]>> Seek, Bricks. Seek. Good boy. Good boy.

[00:25:23]Good boy. Come on. Come on. Good boy.

[00:25:33]>> Meanwhile, Jeff's metal detector has found something promising. So, his team dig it out.

[00:25:39]>> Are you sick? We're doing We're doing very important ecological work.

[00:25:43][laughter] >> Yeah, it's part of a beer can.

[00:25:49]>> Undeterred, it's back to the metal detector and the search continues.

[00:25:56]>> Oh, >> you've got to be kidding me.

[00:26:01]>> You know, someone's been drinking on the job out here, [laughter] I think.

[00:26:09]Oh, son of a Are you kidding me?

[00:26:14]>> That's very promising.

[00:26:16]>> Another hour we'll be able to completely reassemble this cam.

[00:26:21]>> Up in the hills, Brics and Sunny are still nosing about, too. And they've got two offduty cops as part of their team.

[00:26:30]useful, not least because this part of Arizona is notorious for drug and people smuggling from across the Mexican border.

[00:26:42]Several hours later and it's time for the rendevous and one of them has got what they've come looking for.

[00:26:51]>> Hey, well, tell me about it. How'd you do?

[00:26:54]>> Fantastic. Well, >> let me see. Let me see the meteor rights.

[00:26:58]>> We found amazing stuff. You will be so impressed.

[00:27:01]>> I'm always impressed. Let me see.

[00:27:03]>> Thank you.

[00:27:04]>> I appreciate your support.

[00:27:06]>> Here's our array of finds.

[00:27:09]>> Bit of a beer can. Bit of a beer can.

[00:27:12]>> Bit of a beer can. Oh, sorry. Yes. Say that was a really good one. This excellent piece.

[00:27:16]>> Very exciting.

[00:27:18]>> So, uh >> I think you've lost >> the bet.

[00:27:23]>> Well, okay. We found one.

[00:27:26]>> One. What?

[00:27:27]>> We found a meteorite.

[00:27:28]>> Seriously. Serious, serious, serious.

[00:27:30]>> Let's see it.

[00:27:31]>> For any meteorite find to have any scientific value, experts like Jeff need to study it first in >> situ.

[00:27:40]Well, what do you think, Jeff?

[00:27:43]>> Oh, may I?

[00:27:46]>> Yes. Yes. Go away. Be the first one to pick it up.

[00:27:48]>> Oh, this is fant. It's oriented, do you think?

[00:27:51]>> Look at that rounded front, flat back, gorgeous complete stone.

[00:27:58]Well, congratulations. I have to happily declare your team the winner.

[00:28:05]>> Sunny has more than just a victory beer to look forward to. At 75 g, collectors will be prepared to pay around $10,000 for his find.

[00:28:17]For experts like Jeff, it's not the monetary value that excites them. It's any possible insights into planetary formation and the chaos of the early solar system that might result from studying the composition of the rock.

[00:28:32]By looking for meteorites and finding them, we are looking back into the very birth of the solar system. These rocky bodies slam into each other, fragments, and pieces are thrown in all directions.

[00:28:45]They wander through space. Periodically, some of those pieces encounter us and they burn in our atmosphere and they explode and they rain down on our planet and that is a meteorite.

[00:29:02]Astonishingly, every year 40,000 tons worth of meteorites fall to the earth and recently in spectacular fashion.

[00:29:14]In 2013, a meteorite fell near the Russian town of Chelabinsk.

[00:29:25]Nearly 10,000 tons before it broke up.

[00:29:30]Such spectacular events are incredibly rare. But back when the Earth was forming, huge meteorite strikes were constant with tens of millions a year.

[00:29:52]Rather than destroying it, the meteorite onslaught built our planet.

[00:30:00]Starting 4.5 billion years ago, it took just 100 million years to reach almost full size.

[00:30:11]So, the engineer has a planet pretty much the same size as the Earth and the same shape, but at the moment, the surface of the planet is a fiery vision of hell.

[00:30:39]There's no rock. It's just a molten sea of magma.

[00:30:46]There's no way life could start in this volcanic environment.

[00:30:56]So, how do we get a solid surface for our planet?

[00:31:09]Back on the desert floor, Professor Jeff Carlson and his team are setting up an experiment.

[00:31:18]They reckon they can demonstrate how to make land for our planet.

[00:31:28]The first step in their challenge, recreating that early molten earth. And that means constructing what is basically a mobile volcano.

[00:31:42]Inside this cauldron is actual lava.

[00:31:47]It is real lava, basaltic lava. We just put in the ingredients just like a recipe and cook up the this primordial primitive material that makes up our earth.

[00:31:58]The recipe for lava that Jeff's team uses includes the essential planetary ingredients like iron, magnesium, and silicon.

[00:32:09]But before this turns to solid land, he needs to make the lava flow.

[00:32:17]Oh, here. Here it comes. Here it comes.

[00:32:41]The temperatures reached by this lava are extraordinary.

[00:32:47]We know from using our infrared camera where it's incandescent [music] orange there, it's about,00° centigrade. Where it starts to get dark gray, like down at the toe here, it's about 850° centigrade.

[00:33:01]Now it's coming out here 1100 degrees again just like the temperature that we're pouring in. We're sort of replicating [music] those uh conditions of the early Earth in miniature. Imagine the whole planet covered with glowing incandescent orange lava magma oceans. You can see the little wrinkles and folds starting to form in the surface as the surface cools and a crust starts to form.

[00:33:25][music] So, in order to create land from lava, Jeff needs to cool it down until it turns into a crust. [music] Simple. But there is a wrinkle in his plan. [music] On the early Earth, the lava didn't cool in the way you'd expect. There was a reason the surface stayed molten.

[00:33:54]Jeff has a well slightly unusual demonstration of what that was. [music] Side up on the target.

[00:34:03]>> Shooters fire.

[00:34:18]Here's where all the bullets hit. Each one of these little impacts is just like a meteorite striking the Earth and converting kinetic energy to thermal energy, keeping the planet warm and molten.

[00:34:36]These bullets are just like the meteorite bombardment that marked the early Earth's history.

[00:34:44]With a thermal imaging camera, you can see the amount of heat orange on this screen, released by impact.

[00:34:54]It's this kind of energy on a planetary scale that keeps the engineers Earth from cooling and solid rock from forming.

[00:35:19]So to stand a chance of creating a solid surface for the planet, the engineer needs to stop this constant barrage of meteorites and asteroids on the earth. This bombardment peted out around 4 billion years ago.

[00:35:46]On the planet we're building, it can be done in a jify.

[00:35:52]Reducing the impacts from space helps cool the surface. So, lava turns to rock.

[00:36:02]So, our planet has a solid surface.

[00:36:06]But if we want to have life on [music] our new world, the engineer needs another vital ingredient.

[00:36:14]Water.

[00:36:18]Incredibly, some water has been with us from the very birth of our planet, trapped in dust and rock and then locked inside the earth.

[00:36:31]Volcanic activity [music] released this water as steam. forming rainclouds that then filled the first oceans.

[00:36:46]But all that volcanic activity hasn't just pumped steam into the atmosphere.

[00:36:52]It's produced a toxic cocktail of gases.

[00:36:58]So, how do we clean up this poisonous [music] atmosphere?

[00:37:01]Well, the answer lies with the oldest living things on the planet.

[00:37:08]On these rocks, there's a thin film of bacteria called a strumatalyte.

[00:37:16]These ones today are in Australia, but 3 billion years ago, they were everywhere.

[00:37:23]They live on sunlight and carbon dioxide in water.

[00:37:29]And as a waste product, they release oxygen.

[00:37:39]These bacteria pump the stuff out for more than a billion years until the air was ripe for complex life to evolve, including us.

[00:37:57]To build our planet, the engineer started with truckloads of raw materials and mix them together into a cosmic cloud of dust which was stuck together with static electricity.

[00:38:30]And then gravity was added.

[00:38:41]The planet was bulked up.

[00:38:46]Then the meteorite onslaught was stopped to cool it down and make land.

[00:38:57]Finally, water was sourced and a breathable atmosphere.

[00:39:08]But hang on, this isn't right.

[00:39:14]There's something seriously a miss with our planet.

[00:39:20]It's wobbling.

[00:39:26]A wobble this big, even slowed down over millions of years, would be catastrophic.

[00:39:34]Without stability, seasonal change is extreme.

[00:39:39]Ice ages frequent, the surface scoured by constant hurricane force winds. It's no good. The engineers planet has conditions completely hostile to life. But don't worry, because to stabilize things, we don't actually have to look too far. The solution is a moon.

[00:40:08]The explanation of how a moon can stop a planet's wobble can be found at NASA in Texas, where it's kept in a bomb-proof vault.

[00:40:22][music] [music] One man who knows a lot about this object is Harrison Schmidt.

[00:40:35]And that's because he found it on the moon.

[00:40:43]Four decades ago, Harrison was an astronaut. [music] >> December 6th, 1972.

[00:40:50]Dr. Harrison Schmidt, better known [music] as Jack. He would be the first geologist to set foot on an alien world.

[00:40:58]We have commit and we have liftoff at 213.

[00:41:05]>> Practicing field geology on the moon was really a delightful experience. Uh it's a very very good environment for field geology. You have excellent visibility, bright sun. Uh you can move around in the old Apollo 7L suit pretty well. In fact, running across the moon was quite straightforward. I used a crosscountry skiing gate that I had learned in Norway and I could go just about as fast as the lunar rover could go.

[00:41:36]It's the moon that stops our Earth, the one we actually live on, from wobbling with its disastrous impact on the climate. How exactly the moon keeps us stable is tied into its mysterious origins.

[00:41:54]Until the Apollo program, we actually had no real idea of how the Earth got its moon. Finding out was a key goal for Harrison Schmidt when his Apollo 17 landed on December 11th, 1972.

[00:42:12]Fuel is good. Stand by for touchdown.

[00:42:15]Stand by.

[00:42:17]Fuel is good. 10 ft.

[00:42:24]>> Harrison had just 3 days to collect as many lunar samples as possible.

[00:42:30]>> Late in the mission, things got a little tense.

[00:42:34]Harrison had just half an hour of oxygen left and he was getting a little carried away with his work.

[00:42:42]>> I've got to dig a trench.

[00:42:46]>> Fantastic. Sports fans, it's trench time.

[00:42:51]>> They got to leave at a certain time regardless of what we got.

[00:42:54]>> There isn't enough time, Tony, to do it.

[00:42:56]No matter which way you want to do it, we need more time. Jim, you better make it clear to Parker that we got to pull out.

[00:43:04]>> We'd like you to leave immediately.

[00:43:07]>> Okay.

[00:43:08]>> My golly, this time goes fast.

[00:43:17]Once Harrison and [music] NASA were able to examine the rocks they collected, they began to fully understand just how the moon had formed and the massive stabilizing effect [music] this would have.

[00:43:33]Scientists discovered an extraordinary connection. It seems that Earth rock is made of pretty much the same stuff as this moon rock.

[00:43:44]We have uh one of the Apollo 17 samples.

[00:43:47]It's one collected near the lunar module Challenger.

[00:43:51]Uh this uh rock formed based on radiometric age dating uh cool or crystallized about 3.8 billion years ago. All of the rocks that we brought back from the moon on the six different missions are made up of minerals very similar to those that are here on Earth.

[00:44:11]That is the first clue that the earth and the moon are related in terms of their origin. The second clue is a very good one and even more persuasive is that the oxygen that makes up these rocks has certain ratios of their isotopes and those ratios are identical in earth rocks as they are in moon rocks.

[00:44:34]Before uh the Apollo samples arrived back on Earth, uh there were a number of uh ideas about what might be the origin of the moon. And the idea of a giant impact really didn't appear until after the samples had come back.

[00:44:54]The theory is that soon after the Earth formed, another planet-sized rock crashed into it.

[00:45:02]The impact throwing huge chunks into orbit.

[00:45:07]At just 15,000 miles from the Earth, the distance from the US to Australia, the debris clumped together to form the moon.

[00:45:18]>> Spin any uh spherical body in space.

[00:45:22]Uh then you're going to get a wobble. Uh it's technically it's called procession.

[00:45:28]But if you put another body that is gravitationally tied to the spinning body, then that will dampen out that oscillation, that wobble or the procession. And that's the fortunate thing about the moon. It has dampened out the earth's wobble. Now, I can't tell you how life would have evolved if we had had that wobble or that precession, but uh nevertheless, it would almost certainly be very different.

[00:46:00]So, let's see what happens to our planet if the engineer adds a moon.

[00:46:07]Our planet and its new moon are like two dancers locked in a gravitational embrace, steadying themselves as they swirl round and round.

[00:46:26]Having a moon has another vital effect.

[00:46:29]Variations in its gravitational pull give our planet its tides which tempted early life onto land.

[00:46:40]And the actual positioning of the moon is crucial.

[00:46:43]Ever since its formation, the moon has been drifting away from the earth.

[00:46:49]When closer, it generated immense tides.

[00:46:55]If we had them today, they'd put New York and London under tens of meters of water every few hours, but at the right distance from the planet, which in reality is about 384,000 [music] km, and we have the stability we need.

[00:47:18]So there it is, the perfect planetary relationship.

[00:47:24]After trial and error, the engineer has built a planet and its moon and got them working just right.

[00:47:38]In reality, this whole process began 4.5 billion years ago.

[00:47:48]The sheer scale of the task is mindblowing.

[00:47:53]One thing out of order and nothing works.

[00:47:58]Life stops.

[00:48:02]So what holds the Earth and Moon in place.

[00:48:08]They need a sun to orbit around and other planets to make our solar system.

[00:48:19]And [music] all of this is a tiny part of a Milky Way galaxy with 300 billion stars.

[00:48:34]And that galaxy is just one amongst half a trillion other galaxies.

[00:48:41]So to keep it all working, we're going to need to build a universe.

[00:48:59]And to build a universe, we'll need a lot of help.

[00:49:06]>> [screaming] >> Oh my god. Beautiful.

[00:49:18]Kind of like putting on a big onesie.

[00:49:31]There it is. Look at the instability.

[00:49:33]It's shaking.