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The episode introduces the mystery of how Earth formed and explains why the oldest evidence is so hard to find. It follows scientists to meteor crater and into space, where meteorites provide clues to the planet's beginnings.
Earth a unique Planet restless and dynamic continents shift and Clash volcanoes erupt glaciers grow and recede Titanic forces that are constantly at work leaving a trail of geological Mysteries behind this episode travels back in time time to investigatethe greatest geological mystery of all the birth of the earth scientists explore how our planet first formed from the dust of the solar system how molten rocks solidified to land how our oceans filled with water and how lifearrived on Earth these are the earliest chapters in The Incredible story of how how the Earth was
made when it comes to finding Clues to the birth of the earth our planet has been good at covering its
tracks billions of years of erosion volcanic activity and the shifting of continents and oceans have destroyed almost all the evidence of the earliest stages in Earth's formation for geologists trying to discover how and when the earth first formedthis is a major challenge as geologists began to question the age of the Earth and of course they looked for older and older rocks what we began to find was that the further back you go in Earth historythe harder it is to find any of those rocks the search for the oldest rocks on Earth brings investigators to the harsh desert landscape of Northern
Arizona this giant hole in the ground is meteor crater formed when a massive meteorite slammed into the Earth we didn't really have rocks from the very beginning well where could we find something what about the meteorites that havebeen out in space and fall on the earth it was here that geologists made a vital discovery meteorites are older than any rocks on Earth they had found the key that would unlock the secret of Earth'sformation if the oldest rocks came from space that is where the investigation must begin in
space our solar system 4 and 1/2 billion years ago
at its Center the young Sun the theory that emerged was that the sun was surrounded by a cloud of dust and gas and as that cloud cooled little grains of minerals
formed so all these little grains of minerals floating in this gaseous Cloud are moving around the Sun and they start to bump into each other but there was a problem with this Theory nobody could EXP explain how collidingmicroscopic mineral grains could ever create an object the size of a
planet then in 2003 an experiment on board the International Space Station accidentally provided extraordinary new evidence astronaut Don petett wanted to see what happened to different substances in the zero gravity conditions of space he did a simple experimentby pouring some salt into a plastic bag and shaking it the results were astounding the particles immediately began to stick to each other forming little clumps all held together by tiny static electric charges scientists realized that if grainsof salt stuck together in space then so could the mineral grains in the Solar dust cloud
here was real evidence for the fundamental mechanism that kickstarted the formation of the earth as mineral grains in the Solar dust cloud bumped into each other and stuck together they grew into small pieces of rock orbiting the Sunover the next few million years some of them collided and grew bigger many of these rocks are still orbiting the Sun today
they have drifted for the past 4 and A2 billion years unchanged from when they first formed occasionally they fall to Earth and we call them meteorites they provide scientists with an incredible window onto the past we brought awhat's called a Stony type of meteorite what the scientists do then is slice across it and look on the inside and to a planetary mineralist you start seeing all kinds of wonderful things this meteorite contains minerals and metalsfrom every part of the solar dust cloud so what we're looking at is the assemblage of all these little Ancient Ancient Ancient materials that were floating around the Sun in the nebula of dust and gas and when theyhit each other they gradually aggregated into solid bodies which got bigger and bigger gradually billions of these rocks grew as they orbited the sun first to the size of Boulders then as big as houses and they kept on
growing when an object reached about half a mile across its own gravitational pull became strong enough to draw other objects towards it some object in this huge number of objects going around the the sun one of them hadto be the biggest and as soon as it gets bigger than the others it's sweeping up more objects just like you're driving through a cloud of mosquitoes at night in your car in the front windshields getting hit moreoften so the bigger it is the faster it grows and the faster it grows the more gravity it gets and that pulls in more objects so the biggest object starts to run away from the crowd it starts togrow fastest and that biggest object
was the fledgling
Earth soon the young Planet had so much gravitational pull that it began to attract bigger and bigger objects as they crashed onto its surface Earth's size increased with every
impact the bombardment was so intense that it only took about 30 million years for the plan planet to grow to almost its present
Scientists reconstruct how dust grains in the solar nebula clumped together, grew into planetesimals, and eventually became Earth. The chapter also explains how the young planet melted, differentiated into layers, and how radiometric dating finally established Earth's age.
size the young Earth was made of billions of pieces of rock randomly stuck together but geologists know that the modern Earth is not like that below the surface Earth is separated into distinct layers a thin crust then amassive dense layer of rock called the mantle and at the center an iron and nickel core some extraordinary event must have occurred to transform the interior of the young Planet geologists now believe that soon after it formed theEarth completely
melted originally the Earth was probably just a big collection of rocks like this but it heated up to the point where these rocks all melted when that happened the denser elements sank down through to the very core ofthe earth and the LI elements floated at the top the huge gravitational pull dragged the heavy iron and nickel down to form the core and separated the rest of the planet into layers what caused such a huge massof rock and metal to heat up in the freezing depths of space puzzled geologists for many years we think it's from the Incorporation of very hot radioactive elements they're out there floating in space as the Earth accretes itincludes some of this ferociously hot
material as it gets inside there it begins to heat up the Rocks around it and if you build the Earth fast enough and incorporate enough of this really hot reactive elements it'll be enough to melt the Earth fromthe inside out only 30 million years after it began to form War Earth had become a giant round ball of boiling liquid rock and metal orbiting the Sun imagine a totally molten world I mean it had molten magmaoceans uh no no dry land anywhere no water just uh flowing lava everywhere the temperature of the molten Earth was now a staggering 2,000
de but at the edge of the planet the vacuum of space is a constant - 450° almost 2 1,000° colder the surface Rock could not stay molten for long it's cooling from the outside in so from the outsidebegins to crust over and you get this little scab like on a wound of cooled Rock but still really hot and then gradually begins to cool from the outside
in in less than a million years Earth surface was covered in a thin
crust but Vol volcanoes still spewed out lava and choking gases meteorites rained down in a constant
bombardment Earth had a long way to go before it could support continents oceans and life scientists investigating the early EST origins of the Earth have uncovered evidence from Salt grains in space they reveal that the Earth began toform when fragments of the solar dust clouds stuck together the Earth's internal layers provide the clue that soon after it formed the young Planet completely melted scientists had worked out how the earth first formed from a cloud ofdust in space but they were missing a vital piece of the puzzle they still did not know the age of the
Earth billions of years before humans evolved tiny mineral grains in space clumped together to form the molten ball that became the
Earth but exactly when that happened is a question that has taxed the minds of Scholars and scientists for centuries
in 1650 the Irish Archbishop James Usher added up the ages of all the prophets and kings in the Bible his calculations led him to very precise conclusions that Earth was created at nightfall before Sunday October 23rd 404
BC a century later geologists realized that Earth's thick layers of sediments and Volcanic lavas must have been laid down over millions rather than thousands of years the next breakthrough came in 1897 when physicist Ernest Rutherford figured out thatmeasuring radioactive decay could accurately date the age of rocks Rock samples from around the globe were found to be not just Millions but billions of years old but in their hunt for the age of the Earth scientists hita major
obstacle rocks from the earliest stages in Earth history are very hard to find if you want to go back as a geologist and try to find evidence of those early days it's very hard to do on the earthbecause of course we have rain eroding we have tectonics and continental drift destroying Continental surfaces we simply can't find the rocks that go back to that age in the early 1950s the American geologist CC Patterson tried a newapproach using meteorites he knew that meteorites must have clumped together from the same mineral grains in space that formed the Earth and that happened at the same time as the Earth was born so if he could date ameteorite he should get the true age of the Earth in 1953 Patterson came to meteor crater in Arizona looking for samples the meteorite which blasted out this enormous crater was about 50 yards across it slammed into the Earth
at a fantastic speed objects hitting the Earth from space May typically come in at 10 or 15 miles per second hitting the ground penetrating into the ground generating en orous pressure and shock wave and creating a huge explosionthe meteorite hit the Earth with the force of a two Megaton atomic bomb the explosion vaporized most of the meteorite but individual fragments survived this is one of the pieces of the object that crashed into the Earth andmade this crater this is pure iron we know it's iron because for example it's magnetic an amazing piece of something was floting buing in space this was the kind of place that people could get samples for the firstradiometric dating of meteorites and so Patterson came here and got samples like this Patterson dated the samples and was amazed by the results the meteorite was a staggering 4.5 billion years old meaning that the Earth was also born
4.5 bill billion years ago Patterson had solved the problem that had defeated scientists for centuries there's this apocryphal story that Patterson got so excited about the date that was coming back from the laboratory and so hyper about ithe thought he was having a heart attack and he was driven to the hospital and it turned out to be just his excitement over this fantastic Discovery modern radiometric dating techniques have refined the age of the Earth toremarkable degree of accuracy the most recent study dates the Earth as 4 b567 million years old so scientists now knew how and when the earth was formed but nobody had figured out what happened
The story shifts to the collision hypothesis for the Moon's origin and the evidence gathered from lunar rocks. This impact theory helps explain why Earth and the Moon look so different and marks a major step in understanding Earth's early history.
next then in 1974 a radical new Theory emerged in the early solar system there were dozens of many planets chaotically orbiting the Sun according to the theory one of these was on a collision course with Earth the ideawas the brainchild of Bill Hartman who was trying to explain the origin not of the Earth but of the moon what we came up with was that maybe during that period of intense impacts maybe very large impact hitthe earth and blew some crustal outer mantle Rock off of the earth into space around the earth and the moon formed from that material Hartman suggested that another planet about the size of Mars crashed into the
Earth he claimed that the moon could have been formed by debris from that Collision
to many scientists this was nothing but fantasy but Hartman had
evidence collected from the Moon itself I fall in in the plum crater getting this rock footage from the Apollo 16 mission in April 1972 shows astronaut Charles Duke struggling to pick up a large sample of moon rock tobring back to Earth for geologists to analyze that's 20 lb of rock at the Johnson Space Center in Houston this actual piece of moon rock is still kept under strict laboratory conditions I would say behold the moon thisis an actual piece of the Moon and it's the largest single rock that they brought back from the surface of the Moon when the Apollo Astronauts went there we can't touch it they don't want human beings touching theserocks and leave organic material on them until the late 1960s geologists thought that the moon formed in the same way as the Earth by clumps of mineral grains sticking together in the Solar dust cloud they believed it had
layers like the Earth and a heavy iron core but when geologists analyzed lunar samples they were astonished to discover that the moon rocks contained much less iron than they expected one of the Mysteries has always been why isn'tthere as much iron in the moon as there is on the earth if the two two objects are right close together in Space the question bothered Hartman so much that he began to think that conventional theories about howthe moon formed might be wrong that lack of iron in the moon or to put it another way the fact that the moon is made out of rock that looks like the crust and the upper mantle material ofthe earth that was was a clue that the moon may have formed from rocks from the outer portion of the Earth this was the key to Hartman's idea of a collision between Earth and another
planet the force of the impact completely destroyed the other planet and flung billions of tons of Earth's crust and mantle out into space and into orbit theEarth within a few thousand years this debris clumped together to form the
moon Advanced Computer models showed that the Collision was a glancing blow the other planet did not hit Earth head on this meant that while Earth's outer layers were ripped off none of its iron core was blasted away thatlast of iron would end up explaining why why we have a moon that that is only the rocky material without the iron material Hartman's Collision idea is now accepted as fact it was his fascination with the Moon thatled to a new understanding about a vital stage in the formation of the Earth the moon always to me is a reminder that we live in a larger environment than just the Earth it's the Cosmic environment the innersolar system is our environment that we can move around in now in the quest to discover the age of the Earth evidence from radiometric dating of meteorites proves that the earth was formed just over 4.5 billion years ago
The investigation moves to northern Canada, where extremely old rocks show that Earth had a thick crust, continents, and oceans far earlier than expected. These discoveries overturn the idea of an initially barren, molten Earth.
the lack of iron in rocks brought back from the Moon is evidence that the Earth survived a massive collision with another planet but vital parts of the modern Earth were still missing from the newly born Planet the investigationnow needs to figure out how the Earth gained two essential components solid land and
water 4.5 billion years ago Earth formed out of the solar dust cloud then survived a devastating impact with another planet
the investigation now moves 200 million years forward in time as scientists try to discover how the first continents and oceans
formed they are looking for evidence on the northeast shores of Hudson Bay
Canada this is the desolate landscape of porpus Cove the site of an important new scientific discovery and it's all down to a young PhD student's fascination with ancient rocks I was interested in studying the early Earth so theidea is to get as far as we can back in time to get these old rocks and study rocks that were there in the past geologists already knew that rocks in this part of Northern Canada are extremely oldbut something about a small area in this vast Wilderness caught O'Neal's eye the overall aspect of the Rocks really looked different and right away we knew that something was was really bizarre really unusual about these rocks the rocksare highly altered deformed volcanic lavas known as amphibolites the chemistry was unusual the minerology was unusual and nobody had seen rocks like that before O'Neal decided the Rocks needed further investigation he sent samples to be radiometrically
dated the results were astounding we were in the lab in Washington DC when we first got the first number out of the machine and the first the first reaction is we didn't believe it so what you do isyou reanalyze the rock a second time and then the same number comes up and then the third time and then again and again so you say okay we'll analyze more of these rocks because I can't believe it andthese numbers the signature this really really old signature keep coming up keep coming up and keep coming up and in the end you have to come to the conclusion that these rocks have been formed nearly 4.3 billion yearsago the results were indisputable the amphibolites are 4.28 billion years old 200 million years older than any other rocks so far discovered
they are the closest anyone has come to finding Earth's original crust these are the oldest rocks in the world and it's amazing when you stand on it you can try to imagine yourself almost 4.3 billion years ago whenthe Earth was so young and just barely forming walking on this landscape and it's a really amazing feeling these rocks are now y yelding clues about the thickness of the early crust O'Neal has found unusual minerals which canonly form in conditions of very high temperature and pressure they prove that the amphibolites were made at least 12 M down in the crust of the Earth this means that more than 4 billion years ago Earth had asolid crust at least 12 Mi thick and a crust that thick suggests there must have been
continents and there's more evidence hidden in the amphibolites reveals that these rocks must have originally formed deep underwater well you have to understand that when rocks form they can record their chemical signature and depending on where the rocksare form in what geological context they will be formed they will carry that specific chemical signature the chemical signature of the amphibolites is unique it proves that when these rocks formed Earth had not only a solid crust but
oceans the signature we see here it really looks like a no Oceanic floor that means there was an ocean and a lot of water already at 4.28 billion years old so it totally changes our view of what theEarth was like beforeto the scientific world this idea is dynamite but O'Neal is not on his own there is more evidence to back up his claim in the same ancient Rock sequence geologists find another unexpected rock type called banded iron formationsthese rocks are made up of alternating light layers of silica and dark bands full of a mineral called magnetite which as the name suggests are rich in iron we usually use a magnet to to try to find theseuh minerals it's a quick and easy way to uh identify for sure those rock as Bandit iron formation magnetite in banded iron formations only forms underwater so these rocks are further evidence that there were oceans on Earth more
than 4 billion years ago but science don't know how much of earth's surface was covered by water the only way to form this magneti is to be like in a ocean we don't know exactly what was the theocean at that time but we know for sure that we need water to form those rocks these discoveries are forcing geologists to rethink their ideas of what conditions were like on Earth less than 300 million years after theplanet formed people often think of this earlier like a ball of fire a molten rock but this is not the picture that we see here we see that already at 4.28 billion years old we probably had an oceanwe had continent that really really looks like what we know today so it changes totally our view of the early
Earth the investigation has now revealed when the Earth's continents and oceans began to form evidence from amphibolite rocks at porpus Cove confirms that the Earth had developed a thick solid crust 4.28 billion years ago Bandit iron formations inthe same rocks show that there were oceans on Earth's surface at the same time all of which raises another mystery if oceans existed more than 4 billion years ago the investigation needs to figure out where all the water
Scientists trace Earth's water to meteorites that carried ancient liquid water and then amino acids to the young planet. This evidence suggests that both the oceans and the building blocks of life arrived from space.
camefrom after its formation from the solar dust cloud 4.5 billion years ago Earth was a fiery ball of molten rock but 200 million years later the first oceans were already forming and Earth today is the blue planet with70% of its surface covered by water the investigation now looks at the mystery of the origin of Earth's water one of the important questions I've always thought about is you know where did all this come from all thiswater all the water in the oceans and in the atmosphere in our bodies in the ground when you look at the Earth from space what really impresses you is the water how beautiful this planet is why does Earthhave all this water and and how did it get here the question has puzzled geologists for years now they believe the answer lies in space new evidence showing how our water arrived on Earth has emerged from a meteorite
that fell in 1998 but which has only recently been analyzed we found an astonishing thing this miroy contains grains of table salt just like you put in your on your fishion ships the clue is trapped inside the crystalsof salt and revealed under the microscope minute droplets of liquid water on the computer screen you can see a little fluid inclusion a little drop of water and you'll know it's water we know it's liquid because you seea little bubble moving around inside of this little droplet ofwater the amazing thing about this discovery is the age of the water you can date this by several different Tain techniques the salt itself is 4 and half billion years old the water inside has to be at leastthat old if not even older there's no question about it and so this water is at least as old as the solar system here is visible evidence that water existed in space when the earth first formed and zalinsky
is convinced that meteorites then brought the water to Earth and so it's looking more and more like the water arrived drop by drop in in rocks like this mey right here Landing over the course of billions of yearsyou have lots of material coming in every day and and smacking into the Earth and depositing a little bit of water a few drops at atime the scale of the meteorite bombard needed to fill the oceans with water is almost impossible tocomprehend but scientists believe that over billions of years there were easily enough meteorites crashing into the Earth to account for all the water on the
planet gradul those rocks are sweating water building up first shallow Seas here and there that grow to be giant oceans
you go from this tothis once Earth had land masses and water the stage was set for the development of Life the next phase in the evolution of the earth life is an essential element in Earth's geology without life sedimentary rocks like chstock and Limestone would not exist without life there would be no coal oil or gas life has shaped the Earth in profound ways but finding the origin of life has challenged scientists for hundreds ofyears now there's a new explanation it comes from evidence found at aende in the desert landscape of northern Mexico at about 1:00 a.m.on February 8th 1969 night suddenly turned into day a large Fireball was seen traveling from the south northwards over Northern Mexico and this big Flash and this Fireball was caused by a really large meteorite it's probably about thesize of a car and it entered the top of the Earth's atmosphere about 36,000 M an hour as it plunged through the atmosphere the meteorite broke up into thousands of
fragments there was no crater left by the aend meteorite so it fell as a shower of stones the largest of which was reported to be about the size of a beach ball the stones are found in we callit a stun field and it's an area about 30 m by 5 miles wide and we're here right in the middle of that stun field
because the meteorite fragmented into so many pieces geologists had to search a huge area to find
samples now I actually have a smaller one of the stones here you can see it's about the size of a plum it's one of the most primitive type of meteorites this means that since it Formed at the veryearliest stages of solar system formation really not much has happened to it when they analyzed samples from aende geologist just made a groundbreaking discovery the meteorite contained tiny amounts of chemicals called amino acids amino acids are terribly importantconstituents of things like proteins and amino acids really are sort of like the chemical building blocks for life so to find these amino acids these molecules within the meteorite was a really exciting Discovery every living thing on Earthplant or animal contains amino acids and life could not exist without them until they were found in the aende meteorite scientists believed that amino acids were first made by chemical reactions on the surface of the Earth people thought
that maybe life had started on Earth in these sorts of warm pools maybe you know few hundred million years after Earth actually formed or possibly through lightning causing chemical reactions in the early atmosphere there was a few theoriesas to how life may have started on Earth prior to the discovery of amino acids in meteorites since aend day amino acids have been found in hundreds of other meteorites their Discovery has revolutionized ideas about the origin oflife on earth scientists now believe that the building blocks of life originally came from space meteorites containing amino acids have bombarded Earth ever since the planet formed and it was these amino acids which were the starting point forall life hunting for the origin of Earth's water and life the investigation has revealed that the water on Earth arrived here inside meteorites and meteorites also brought amino acids the building blocks of life to Earth from from space
The final chapter explains how cyanobacteria produced oxygen, transforming Earth's atmosphere and enabling complex life. It concludes by summarizing the major milestones in Earth's formation, from dust grains to continents, oceans, water, and life.
scientists now need one more piece of the puzzle to explain the final stage in Earth's Journey from particles in the Solar dust cloud to a planet where life itself builds Earth's geological
features 4.5 billion years ago Earth formed out of the solar dust cloud 200 million years later the first continents in oceans were developing meteorites brought water and amino acids the building blocks of life to the surface of theplanet the investigation now moves forward to the period 3.5 billion years ago new forms of life were about to emerge which by their very existence would create new kinds of rocks but Life as we know it needs oxygenand 3 and2 bill million years ago there was no oxygen onEarth at the time the atmosphere was deadly poisonous volcanic eruptions filled the air with a choking mixture of sulfur methane carbon dioxide and sulfuric acid but primitive life forms did exist the fossilized remains of strange coral-like structures havebeen found in rocks more than 3 billion years old in many parts of the world they are called stratales and they are a clue as to how the atmosphere filled with oxygen living stratales are incredibly rare one of
the few places on Earth where they can be found is in another part of the northern Mexican
desert this is the high Valley of Quattro cenus you might think that this is just any old desert but it's not this is a very special place because of particular way the chemistry is in this Valley it's unlikeany other place on the
planet the pool is like a time capsule laboratory by examining the modern stromatolites scientists can work out how they were made more than 3 billion years ago what's interesting about quatrro cinus is that this is almost like aproxy to right before the world had a lot of oxygen in it and the place was dominated our Earth was dominated by microbial life Seaford has discovered that the stromatolites are made by billions of microbes called cyanobacteria theseright here are the stromatolites that are here at quatro cenus I have a piece of it here and if you can see this blue green Rim right here this is millions and millions of cyano bacteria these bacteria wereto change the course of Earth history because of one unique feature they produce oxygen here at this Pond we can actually see them doing their job we can see them making that oxygen so when I get in the
water and I actually go up to one of these cyanobacterial mats if I look very closely all of the community is making oxygen and as that oxygen collects in that mat it produces a little air bubble and youcan watch that air bubble just transfer to the top and that's actually when oxygen is being released to the
atmosphere 3.5 billion years ago oxygen was deadly poisonous to other early life forms which used sulfur to obtain energy cyanobacteria developed a little molecular machine that could actually take sunlight and take water and they made a a byproductthat was oxygen well on this planet back then none of the life was used to oxygen and it's at that point in life's history when they began making excess oxygen that got into the atmosphere our whole world changedin the way it worked over geological time they were in cyanobacteria to produce trillions of tons of oxygen creating the atmosphere we breathe today and they were responsible for changing the way all life evolved from an evolutionary standpointon planet Earth we are where we are because of cyanobacteria and the fact that they managed to fill our atmosphere full of oxygen Because unless we'd had that gas we wouldn't have the complex organisms that we have on
the planet you and I wouldn't be here today once the atmosphere began filling with oxygen the stage was set for the evolution of all plant and animal life the impact on Earth's geology was profound over hundreds of millionsof years decaying plant matter from tropical forests built up compressed layers which eventually formed all the coal oil and gas deposits on the planet sedimentary rocks like Limestone and chalk are made largely from the skeletons of marine animalswhich accumulated at the bottom of shallow seeds without life Earth's geology would be very different the investigation into the birth of the Earth has uncovered evidence revealing the secrets of Earth Earth's development experiments on salt crystals in spacereveal that the Earth began to form when mineral grains in the Solar dust clouds stuck together evidence from meteorites proves that earth first formed 4567 billion years ago the oldest rocks in the world are evidence that continents and
oceans were forming 4.28 billion years ago much earlier than previously thought liquid water in meteorites proves that water was brought to Earth during billions of years of meteorite bombardment 3.5 billion years ago a billion years after it firstbegan to grow out of the solar dust cloud Earth had continents oceans primitive life forms and oxygen the birth of the Earth was complete a new canvas on which billions of years of geological processing could mold the planetwe inhabit today