3 Hours Of Fascinating Space Facts To Fall Asleep To

our world formed through a series of devastating cataclysms it could have literally blown the Earth to bits and then we wouldn't even have a planet today an apocalyptic planetary collision millions of brutal Cosmic strikes and the most powerful blast in the universe a supernova our Adams would have been SC added into outer space yet these catastrophes created the planet we know today the Earth is an incredibly special place it seems like everything has worked out just perfectly could other planets have form the same way if so the universe could be full of earths and full

of life [Music] our planet is extraordinary it provides everything life needs trillions of creatures plants and us will you look down at the Earth from space and everything that we know of that's life is down there on that planet that beautiful planet that you now are going around every hour and a half and that's almost overwhelming just the beauty of the earth it's Unique in our solar system but is it unique in the universe it's important for us to understand the conditions that led to the formation of the Earth because then we can look for

those conditions around other stars and if we find those conditions there then that would suggest that other Earths could be forming elsewhere in the universe could there be other planets like ours Among the Stars to find out we must travel back in time and discover how the Earth was made rewind the clock 4 and A2 billion years and this is what you see this Speck of dust will become the Earth by combining with countless others they're all part of a giant Cloud called a stellar Nursery the first step of planetary formation is about to [Music]

[Applause] start an event that will transform the cloud into thousands of infant solar systems including our own the same process is happening today 7,000 light years away in the Eagle Nebula our own solar system formed inside clouds of gas and dust like these there are these three trunks of gas and they're nicknamed The Pillars of Creation and they're they're trillions of miles long these are huge structures the cloud look dense but they're actually very sparse these gas clouds are incredibly tenuous you'd have to compress basically a Mountain's volume worth of this stuff squeeze it down

just to make a little tiny Rock like this to compress the gas and dust into dense stars and planets takes a supremely powerful event one that can only follow the death of a giant star in 2007 the Spitzer Space Telescope captured this [Applause] image a ball of hot gas behind the Eagle [Music] Nebula evidence that a huge star has exploded and sent a vast wall of gas racing toward the pillars there a wave of hot material approaching the pillars of creation and this may be a shock wave from a supernova a dying [Music] star supernovas

briefly outshine entire galaxies superheated plasma blasts into space at 70 million mph a mighty shock wave speeds toward the pillar of creation when it hits it will demolish them it will also create new worlds Supernova shock waves smash into the pillars compressing the thin gas and dust into dense clumps each is a new St star a new solar system molecular cloud minding its own business gets blasted by a supernova explosion crushing the cloud down into stars and planets wind back 4 and2 billion years and our solar system starts the same way a supernova crushes a

massive Dusty Cloud into a pro planetary disc a thin nebulous Cloud becomes a dense Whirlpool of gas and dust a solar system in the making one star is destroyed a new Star is Born our sun and its planets this is the first link in the long an unlikely chain of events that made our world for Earth to even be here we had to beat astronomical odds a host of different factors have to line up to get a planet just like the Earth you have to have the right distance the right size the right kind of

moon on Earth all the conditions are just right for life to get a world like ours you need a lot of Aces somehow our solar system hit the jackpot but the big question is did it happen anywhere else one of the universe's most violent events triggered the birth of our planet a sparse Cloud crushed into a dense swirl of dust some of this dust will become planet Earth but how do tiny dust grains create entire worlds a supernova explosion triggers a chain of events that will eventually create the Earth the formation of of our solar

[Music] system a hot ball of gas grows in the center this will become our sun the dust that swirls around it will form the planets but first the grains must stick together so we have this interesting conundrum right so this disc consists of gas and dust particles they're about the size of let's say particles in Smoke right let's say cigarette smoke right so these are small things and somehow we have to get from those little grains to what we see on the earth gravity is a powerful attractive force it shapes galaxies and solar systems but

specks of dust are far too small to pull on each other somehow they Clump together to form planets so if gravity doesn't bind them what does in Germany scientists are on the case okay they can simulate how dust behaves in space inside a huge Tower here we do freef fall experiments so um the whole experimental setup including our dust Aggregates are in perfect free fall it is simulation of space but a very good one indeed I think this is the closest you can get to space on Earth researchers Place dust in a container and load

it into a launch capsule at the base of the tower they lower it into a super powerful catapult this long launches the/ ton capsule from 0 to over 100 mph in A4 of a second 400 ft up the capsule reaches the top of the tower then plunges back down a drum of polystyrene balls 30 ft deep breaks its fall all this gives just 10 seconds of zero gravity just enough time they hope for the dust to stick 3 2 1 and go moments after the capsule launches the dust inside becomes weightless the grains Clump together

just like the early solar system these images reveal how dust particles came together 4 and2 billion years ago to form the Earth the force that binds the Aggregates together is not gravity they are too small for Gravity to be uh efficient um we think the force that that binds the Aggregates together is electrostatic force it's the the same reason that when you pull your clothes out of the dryer you know how the clothes sometimes stick to you that's the same uh effect that allows one dust particle to stick to another dust particles join to form

balls of fluff the little static charges that they have can make them stick when they hit and you get something sort of like the dust bunnies that I have a lot of underneath my bed these Cosmic dust bunnies are planets in the making they start out smaller than a pin head then grow the dust is now in clumps but it's still just balls of dust turning dust balls into rocks takes a whole new process a cosmic electric storm space clouds build up charge just like clouds here on Earth generating huge bolts of lightning balls of

dust can turn into solid rocks by an energetic event like lightning the electric bolts smash through the dust balls and heat them to 3000° f in minutes they cool and fuse into Solid Rock meteorites today still carry these ancient Rock balls inside them these tiny globules were once the building blocks of planets to form the Earth these tiny balls must Collide stick and grow rocks begin to build up by accidental collisions which can take a long time eventually the protoplanets as we call them the baby planets get the size of asteroids kilometers across the baby

Earth is now the size of a few city blocks big enough for a new Force to take charge gravity at that point a single asteroid will gravitationally attract a neighboring asteroid and so those two asteroids that would have passed in the night are gravitationally attracted and they hit each [Music] other once gravity starts to rear its head things really speed up because instead of just randomly plowing through material and and getting bigger that way now it's starting to draw material [Music] in gravity pulls rocks together then holds them there to produce bigger and bigger piles

of rubble so this formation process which was taking a long time to get to the size where gravity kicks in suddenly gets kicked into overdrive and the planet grows very rapid but planets are more than just overgrown Rock piles these rocks are lumpy and inert how did the Earth become round and full of life the early solar system is a construction site for planets dust sticks together to form rocks rocks join to form asteroids but most asteroids look nothing like Earth and when you look at a close-up of an asteroid it looks like some kind

of distorted peanut like a potato that's been sort of bashed you can see giant craters and oblong shapes the young Earth is one of billions of misshapen space boulders to become a planet it must first become round that process only starts when it's several hundred miles across when its own internal gravity begins to change its shape once you get enough material enough Mass the gravitational force becomes stronger any Giant mountain will be crushed down by the force of gravity the gravity is so strong that can actually break rocks and the Rocks itself can act like

a fluid making an object br huge outcrops of rock crumble and fall the immense self-gravity of the early Earth crushes it into the most efficient shape a vast round ball of rock a lopsided pile of rubble transformed into a miniature world the Earth has a new shape but it's still just a ball of rock its structure will also soon change Cosmic rocks and boulders still rain down from space each Collision heats the ground there's a huge amount of energy stored in an object that's moving rapidly and when that hits the Earth all that energy is

dumped into the material and that heats it up and melts it and the Earth became molten and stayed that way for a long time the young planet is no longer Solid Rock it's a seething molten Mass just like this Blast Furnace at the severall plant in Detroit believe it or not this process behind me makes life on Earth possible they feed in ground up iron ore a mixture of rock and metal just like the early Earth put iron ore in a furnace and the heat melts everything this molten iron is at 2,700 de F that's

about the temperature of the surface of the Earth 4 and2 billion years ago imagine an entire planet molten in the distance you would see thundering volcanoes spewing out lava it will be a scene right out of Dante's Inferno [Music] iron is heavier than Rock now molten they separate this is amazing we're witnessing a process which created the very crust of the earth billions of years ago the crust that we walk on every day molten rock Rises to the surface and cools to form the crust molten iron sinks underneath inside the earth it sank all the

way to the planet's core the rocky surface is where we live but without Earth's molten iron core none of us could [Music] survive this process separated the iron from the rocky minerals as the iron descended to the Center of the Earth it eventually created a magnetic field and that's why we're here today the molten iron swirls inside the Earth's core and generates a powerful magnetic field around the planet a cosmic Shield against deadly radiation from space but the young Earth is still small far smaller the than the moon today this newly formed world must grow

it must also avoid being blown to Pieces thousands of protoplanets are hurdling around the solar system and some are heading straight for Earth [Music] it's a 100,000 years since our solar system formed the young Earth already looks like a planet it's round it has an iron core and a rocky surface yet our baby planet is just a few hundred miles across it has a long way to go it must grow 4,000 thousand times more massive and it has competition thousands of other protoplanets shoot through the solar system often colliding at over 20,000 mph you can

find proof of this ancient destructive era in modern-day Arizona not meteor crater itself that's just 50,000 years old but the asteroid that gouged it out that was 4 and A2 billion years [Music] old Mark Sykes and Marvin Kilgore think the asteroid came from a violent event in the early solar system the asteroid flew through space for billions of years then it hit Earth they aimed to find a fragment of the asteroid a Remnant from the period of planetary formation about 6 mil from here is meteor crater and that was a impact 50,000 years or so

ago and it spewed a bunch of pieces out they're convinced the original asteroid was rich in iron so they've come prepared with some impressive metal detectors does it work oh yeah that's the sound we're listening [Music] for but even with a quad drawn metal detector meteorites are hard to find yeah are you pretty convinced there's nothing there I yeah I don't really uh not not detecting anything they find metal but no meteorites my great discovery of the afternoon has been this bolt and this piece of wire [Music] it takes hours of searching and many false

alarms then with the light fading the detector sounds [Music] again how about that success at last this meteorite is over 90% iron and nickel It could only form right in the core or of a protoplanet the protoplanet it came from must have smashed apart in a brutal Collision well in the uh early solar system it was a pretty violent place and uh these protoplanetary embryos would smash into each other they would shatter each other exposing the interior cores like this was very tumultuous [Music] time entire worlds reduced to chunks of rock and metal and Scattered

into outer space in the early solar system these vast collisions are common the young Earth is in danger the period's name is the Titan noachian literally the war of the Titans all rocky planets the Earth included go through this destructive phase sometimes they shatter completely sometimes one consumes the other all the big guys are sort of competing with one another in a very violent way actually to see who comes out on top by eating all their neighbors the battle lasts over 30 million years finally thousands of protoplanets have combined into a few fullsize planets Mercury

Venus Earth Mars and a fifth planet Thea it's racing toward Earth our planets last giant impact Thea is the size of Mars big enough to destroy the Earth if that thing had hit us straight on it could have literally blown the Earth to bits and then we wouldn't even have a planet today if this mars-like object had a direct hit with the Earth perhaps there would have been another asteroid belt where the Earth is today but Earth is in luck instead of a head-on crash Thea strikes a glancing blow it's the most violent event the

Earth has ever known the impact turns the Earth back to a molten World a vast magma ocean six 00 mil deep the Earth barely [Music] survives and the encounter changes our world forever material blasts out into space enough Rock to build a mountain as wide as America and 10,000 mil High it would have been so much energy so much catastrophe huge amounts of material blasted off and went into orbit around the Earth the debris forms a huge ring around the earth this gathers together to form two Rocky bodies both orbiting the Earth something the size

of Mars hit the earth about 4 billion years ago lots of material would been thrown off we now think that it may have formed not only one moon but two for millions of years Two Moons dominate the earth's [Music] sky eventually they drift together and Collide two moons merge into one the massive Moon we see today there's no other planet that we know of that has a moon as large as ours in comparison to the size of the planet we're almost a binary Planet Two Worlds going around each other without this large Moon we might

not even be here the moon plays a key role in the survival of life here on the earth and the reason is that the moon in its orbit stabilizes the Earth the moon keeps the Earth spinning at the same angle that steadies our climate the fact that the Earth's axis stays in the same direction as it goes around the sun produces the seasons but regular seasons things that life can depend upon as it evolves Earth is not neither too hot nor too cold for Life thanks to our distance from the Sun and our massive [Music]

Moon the Earth is not covered in ice or steam but in liquid water yet that water must come from somewhere the newly formed Earth is dry to get water our planet must once again face disaster it's half a billion years since the sun first ignited 4 billion years from now the first humans will set foot on Earth the moon has just formed and the Earth is a [Music] desert one of the more Amazing Ideas in astronomy is that the earth started out hot and dry there was no water here originally as the planets formed the

sun's intense radiation vaporized the water in the inner solar system farther from the Sun temperatures were cooler so in the outer solar system ice and water collected on comets and asteroids while closer to the Sun the young Earth was dry so things changed what happened how is it that now we have this wonderful water cycle well the water probably came from somewhere else if you want to have a solar system that has a lot of water in it you have to bring it from the outer parts down into the inner parts and you can do

that through comets and asteroids comets and icy asteroids contain huge reserves of water but they're hundreds of millions of miles from The Young Earth then something changes an event that tosses the the asteroids and comets right across the Solar System Jupiter Saturn Neptune Uranus take a cosmic roller coaster ride so this isn't an event that happened when the solar system was young think of it as more of its teenage uh breakout years where they just started the party for a while the Young planets have not yet settled into stable orbits as their orbits shift Jupiter

and Saturn fall into an intricate dance every time Saturn orbits the sun once Jupiter orbits twice so they always line up at the same spot each time gravity tugs them in the same direction first first they destabilize each other and then the entire solar system the whole thing just goes KY the analogy I like to use is when a bowling ball hits pins just goes bam all over the place that's what this would have looked like planetary pandemonium Neptune and Uranus switch places Saturn races outwards the giant planets scatter billions of of asteroids and comets

onto New Paths many head for Earth these asteroids and comets would have been scattered all over the place right some of them hitting the Earth and Moon Cosmic missiles bombard the Earth we believe that every square inch of the earth got hit by a comet or an asteroid during this period it would not have been a fun time to be here the bombardment lasts hundreds of millions of years until finally the gas planets settle into the stable orbits we see today restoring order but Earth itself has fundamentally changed those comets and asteroids were not just

made of rock but of ice frozen water comets we know are made out of ice they're dirty snowballs in out of space and even asteroids can bring water and ice to the Earth our oceans are full thanks to the cosmic hail storm so next time you're drinking a glass of water realize that you're probably drinking Comet and asteroid juice the arrival of water is the final step to create a habitable planet a sequence of catastrophes has created a world that's perfect for life but has it happened elsewhere Among the Stars or are we alone [Music]

how did we get here planet Earth only exists because of a chain of extraordinary events a lucky throw of cosmic dice 5 billion years ago the odds would have seemed extremely slim that a planet like Earth would form in a rather unremarkable arm in the Milky Way galaxy it's like trying to throw two sixes but with dice that have thousands of [Music] sides we know it happened once else we wouldn't be here but what are the odds it happened elsewhere that other planets have life life like ours needs a planet with the right temp temperature

and size a stabilizing Moon a protective magnetic field and just the right amount of water the conditions must be [Music] perfect yet amazingly there may be countless earthlike planets out there waiting to be found thanks to the sheer Scale of the Universe we may find one any day now with the Kepler space telescope Jeff Marcy is Mission co-investigator it has only one goal and that's to discover earth-sized planets around other stars that you see in the night sky earth-sized planets are hard to spot before Kepler astronomers took 20 years to discover around 500 planets most

were gas giants hundreds of times bigger than Earth since Kepler that number has exploded Kepler has already discovered a couple thousand Planet candidates uh many of them are members of multi-planet systems two three 3 four five and even six planets all orbiting the same star so we're finding an absolute Avalanche of planets out there Among the Stars kep is found one planet only twice the size of Earth and the right temperature for life we don't know yet if this planet has other earthlike attributes like liquid water but even if it doesn't there are many more

planets out there Kepler is found only a tiny fraction of them because it only looks at a small part of the sky it's not even looking at the whole Sky it's looking at a very tiny slice of stars in the galaxy and in fact if you were to look up you could cover it with just your thumb in the whole of our galaxy there are 200 billion stars many will have planets based on our knowledge from Kepler and other searches something like half of those Stars perhaps even more Harbor planets that means at least a

100 billion planets have formed in the Milky Way earthlike worlds may be rare but it seems a safe bet that they're out there somewhere so the odds of getting an earthlike Planet are extremely small much smaller than getting a double six at craps but if you have a lot of dice you're guaranteed to get sixes and if you have a lot of planets you're guaranteed to get Earths there are so many planets in our galaxy even if the chances are one in a million there should be thousands of earthlike Worlds our universe at large has

hundreds of billions of galaxies Each of which is more or less like our Milky Way so the number of planets in our universe is virtually uncountable alien Earths must be everywhere now we haven't discovered even one of them yet but statistically speaking it is a rock solid certainty there are millions of billions of planets like the Earth out there and with that many earthlike planets surely some of them will have intelligent life I would bet everything I would bet my house that there is another Earth out there somewhere there really can be no doubt that

elsewhere in our universe there are other smart Critters who are asking themselves gee I wonder if there are any other intelligent species out there in the universe the night sky is full of stars galaxies planets and asteroids asteroid actually means star-like even in the very best telescopes they look like nothing more than just points of light in the in the sky they're Cosmic Boulders and there are trillions of them from the size of a car to Giants hundreds of miles across together they tell the story of how we came to be the Earth was made

by asteroids 4 and 1/2 billion years ago the solar system is a vast Cosmic Whirlpool dust stick together to create asteroids in our own solar system and in every solar system the first objects to form the first large rocks before planets form are essentially asteroids there are no planets yet instead trillions of rocks and stones swirl around the newly born Sun it would have been a very strange place kind of like a mer around of all these OB objects orbiting around the Sun and there are millions of these asteroids that are just in different sizes

and different shapes these ancient asteroids will shape the solar system and build the planet we live on asteroids are so much more than just rocks in space they're the building blocks of our very own Planet billions of small asteroids must Clump together to make a planet but asteroids move at thousands of miles per hour getting them to stick is hard we're here at the stock car RAC see what the early solar system may have looked like high-speed car collisions cause damage Parts smash on off asteroid collisions are the same to join together somehow they must

Collide and stick stock cars show how this happens they move fast but all in the same direction just like the asteroids in the early solar system when collisions happen they're relatively gentle instead of Smashing apart they join together these are planets in the making they're going around almost at the same speed and they begin to stick together and that's how planets begin to form asteroids gather into rock piles like two cars locked together as more asteroids Collide the rock piles grow building whole planets this way would take billions of years yet the planets formed in

just a few million years how when the rock piles reach Mountain size gravity speeds up the process gravity started to become important when they were about the size of one of the Rocky Mountains like pik's Peak behind me it was when they were several miles across that they had enough mass that their gravity could start to draw material in now if the Earth weren't here and it were just Pike's Peak over there a few miles away I would very slowly start to drift toward it faster and faster accelerating the whole way until I actually impacted

it the gravity would draw me in it would pull on me until I actually hit the mountain itself large asteroids are mountains in Space the early solar system is full of them their gravity pulls other asteroids toward them the larger an asteroid becomes the more rocks it pulls in and the faster it grows at that point the events happen very quickly it would actually draw that stuff in and grow very rapidly one of these early space mountains keeps on growing until there are no rocks left to pull in it's no longer an asteroid it's a

young Planet the Earth all of the planets even the Earth they owe their existence to the fact that there were asteroids back then this is how all rocky planets form asteroids join together until there are no more left Mercury Venus Earth and Mars are all overgrown [Music] asteroids but beyond Mars something went wrong no rocky planets in instead billions of rocks and boulders that never join together the asteroid belt out here construction came to a halt before a rocky planet could form because of Jupiter the gas giant had already formed nearby Jupiter is humongous it's

the 800lb gorilla it dominates everything gravitationally 4 and A2 billion years ago Jupiter's gravity causes Havoc it flings asteroids in every direction giant Boulders scatter from their regular orbits onto extreme chaotic paths the stock car race ends and the demolition derby begins once Jupiter got involved the solar system began to look like a demolition derby things colliding with each other going in all sorts of different directions a cosmic pile up rocks smash into each other from every direction violent chaotic collisions these rocks don't Clump together they shatter and create the asteroid belt violent collisions Still

Rock the asteroid belt today in 2010 the Hubble Space Telescope captured this the aftermath of a hyper velocity Collision asteroids can both create and Destroy if many of them come together gently you get planets too much violence and you get the asteroid [Music] belt billions of rocks and boulders a graveyard for a planet that never [Music] formed the asteroid belt is a mysterious realm full of danger and full of Promise a new frontier just waiting to be [Music] explored asteroids are as diverse as planets or moons some are metallic some rocky some Icy some even

have their own moons they come in all shapes and sizes from Boulders all the way to miniature worlds and they're everywhere distant solar systems have their own asteroid belts the star Epsilon aradani is just 10 light years away it has not one but two asteroid belts another star has a belt 25 times larger than our own if you're actually living on a planet in that solar system the asteroid belt would look like a much brighter than the Milky Way a big streak across the night sky asteroid belts are the scraps left over after planets have

formed so they tell us a lot about their solar system our asteroid belt is full of variety millions of strange asteroids each with a story to tell yet we have barely explored it at [Music] all that's about to change the first mission to the asteroid belt is underway the dawn probe its goal to explore a mysterious distant realm we're going to learn more about the main belt asteroids from this one Mission than we will have since we've discovered the asteroid belt in the first place in July 2011 Dawn arrived at its first Target and sent

back these pictures Vesta is the second largest asteroid in the belt it almost became a planet then Jupiter's massive gravity stunted its growth today it's a miniature world one of the common misconceptions about the asteroid belt is that things are fairly small but some of the largest asteroids are really more correctly thought of as minor planets they're several hundred miles across Vesta even has a mountain three times higher than Everest Mark Sykes is co-investigator of the mission it's just a real excitement because you're seeing a new world for the first time and and and you

know just enough to be dangerous in trying to explain what it is that you're seeing Festa is like a snapshot of the infant earth when it was just as wide as Arizona we're seeing perhaps what an embryonic early terrestrial planet like Earth looked like in the in the first few million years of its history the dawn probe has already found that Vesta has an iron core like the Earth evidence that the Earth's core formed when the planet was still young this stunted World offers us a window on the Earth's distant past we're seeing things that

we didn't necessarily expect but that's what makes it fun after Vesta the dawn Mission will head into the asteroid belt's outer reaches to explore and icy primeval world four times bigger than Vesta there Dawn aims to settle another mystery about the Earth's past where did our oceans come [Music] from the asteroid belt is ancient violent and remote hundreds of millions of miles from Earth but not all asteroids stay in the asteroid belt they can roam all over the solar system the moon's surface records a violent past a massive Cosmic bombardment we see evidence every night

when the moon comes out what do we see a pockmark Barren World evidence that there was an intense rain of asteroids and debris that came from outer space completely disfiguring the surface of the Moon millions of craters cover the moon including the largest in the solar system 1,500 mil across itself scarred by thousands of smaller craters a storm of asteroids blasted the moon 4 billion years ago and if that happened to the Moon it must also have happened to earth the earth is a much bigger more massive Target in space for every one of those

craters you see on the moon you've got to imagine 50 or 60 craters here on the planet Earth Earth the impacts back then must have been horrendous every few weeks a gigantic object hurling from out of space gouging out a huge chunk of the planet Earth we call it the late heavy bombardment for 200 100 million years Fireballs rain from the sky the impacts trigger earthquakes bigger than any in recorded history 10,000 mph hurricanes rip through Earth's primitive atmosphere but asteroids also bring a new substance to Earth some asteroids contain ice frozen water that melts

on impact each asteroid brings a little more but could asteroids really bring enough water to cover 2/3 of our planet one of the questions we have is how did water get to the Earth because the original Earth we think was very hot and very dry NASA's Dawn probe aims to find out the asteroid belt still contains icy asteroids to this day in the coldest most distant part in 2015 Dawn will arrive at the Solar System's largest asteroid series series is 1/3 the mass of the entire asteroid belt and four times as large as any other

known asteroid a lot of it looks like pure ice Series has a rocky interior and icer mantle it's far enough away from the sun it's cold enough that that it's stable series is just 600 mil wide yet there may be more frozen water here than all the fresh water on Earth the dawn Mission will find out for sure if series really does hold so much ice it could help explain why the Earth has so much water when asteroids bombarded the Earth 4 billion years ago massive icy bodies like series could have brought vast am amounts

of water water itself in the form of ice came down from the Heavens to create the Lush oceans of the earth and not just the oceans clouds Rivers glaciers may all have come from space the dawn mission may uncover something even more significant on series it may find an ocean underneath the ice an inner mantle of liquid water melted by heat from the dwarf planet's core Life as we know it depends on water wherever we find water we may find the spark of life if there is a liquid water ocean underneath the surface to day

that begs the question whether there could be life there extraterrestrial life could have started in the asteroid [Music] belt series could be home to basic life forms flourishing in a subsurface [Music] ocean if asteroids like sir can support life that could reveal how life started on Earth 4 billion years ago asteroids bombarded the young Earth they brought water and they may have brought life from the asteroid belt to Earth's new oceans primitive organisms that thrived and ultimately evolved into all the Earth's creatures a planet that brims with life our earliest ancestors may have arrived from

the asteroid belt perhaps these little worlds could be incubators of Life uh throughout our solar system maybe even and know the solar systems Sur Their Stars asteroids may bring life to Worlds throughout the Universe they may also bring death asteroids are crucial to life in the universe but once life gets started asteroids can also end it asteroids really have two sides to them they're sort of creation and destruction all wrapped up together planet Earth is right in the firing line we've come to realize in recent years that we live in this kind of a cosmic

Shooting Gallery astronauts witness this firsthand when I flew on Apollo 9 and I went outside to spacecraft it's very likely that I was hit by you know very very small asteroid and you know it it will make a hole in a space suit most objects in the earth's vicinity are tiny but they move at thousands of miles per hour so the suits are very very well built the result of which is they're very heavy but you know we've never had one penetrated yet the Earth too has built in protection from small asteroids the at atmosphere

when asteroids hit the atmosphere they burn I can remember one night when we were looking down at the dark Earth and I kept thinking I saw an occasional flash of light but I wasn't sure and then suddenly we're realizing of course you know we're looking at shooting stars most people don't realize that on a given night if you lie in the grass and look up at the night sky you'll see shooting stars many of them each hour most shooting stars are the size of grains of sand these burn up but larger space rocks can punch

right through to the ground here's the proof meteor crater in Arizona gouged out by an asteroid just 150 ft across you can see the huge force that excavated this and you can also see the layers of material that were that were turned over uh uh as as the crater was excavated and so uh some of these rocks around here are kind of upside down from where they started there have been millions of impacts like this in Earth P there will be more imagine a city where meteor crater is now they see a fireball coming through

the sky very quickly you know this thing is moving at 8 m a second and so it wouldn't take very long for it to move across the sky and strike the ground heat from the Fireballs scorches the surface but most damage comes after the impact once it strikes ground this takes a few seconds to create so very short time very large amount of energy and uh very devastating effects the asteroid is obliterated a mighty shock wave generates winds six times more powerful than a hurricane you have the blast that comes out probably for several miles

and large debris that would Crush buildings and and homes if it hit today the asteroid from meteor crater would be a city killer but the meteor crater asteroid was small it was likely a fragment from a much larger asteroid whatever it is that hit in meteor crater wasn't very big it was probably 50 50 yards across so not even as big as a football field there are millions of much larger asteroids these would cause even more Carnage country killers and worse asteroids over a half mile wide could end our civilization worldwide Killers we know because

it happened [Music] already there are traces everywhere there's evidence of giant impacts all over the world and it's right underneath your feet and in fact in some places it's pretty easy to spot like here in Southern Colorado [Music] so this layer of light colored Rock that's the KT boundary it's called a boundary because it marks the boundary between two different time periods everything that was put down here underneath the KT boundary had dinosaurs in it everything above it no dinosaurs so it really marks that point in time when the dinosaurs went away the lair is

rich in an element called iridium it's rare on the Earth's surface but common in asteroids so if a giant asteroid came in smacked into the Earth blew out dust everywhere the idium inside the asteroid would have settled down into a layer all over the Earth and that's exactly what we see right [Music] here the clear fingerprint of an asteroid there must have been some perfect morning before the as asid impact when the land of the dinosaurs was still very much as it had been for millions of years then there would be something sighted up in

the sky something very bright very hot the asteroid is 6 M long big enough to devastate the planet the asteroid that came in and formed this layer here was very massive and was moving very fast and so when it impacted the Earth that energy was turned into boom very very big boom it has the force of 5 billion heroa bombs large pieces of Earth blow out into space then rain back down a storm of fireballs wildfires rage across the globe [Music] in the KT boundary layer is a layer of soot and that's an indication that

there were Global fires that everything on Earth was basically on fire after this happened the Earth plunges into darkness an impact winter mass extinction basically you can think of this as every environmental catastrophe all happening at the the same time it was an incredibly bad day for planet Earth a chilling reminder of the threat from [Music] space asteroids this big will hit us again we will go the way of the dinosaurs we will be survived most likely by the bugs the Cockroaches they will be the ones who will inherit this Earth but hopefully that's going

to be a long time from now is mankind doomed or can we Dodge [Music] fate asteroids built our world they brought water they killed the dinosaurs and made room for new species but asteroids are also a [Music] threat we know absolutely for certain that there will be large impacts in the future so it's not a question of if it's only a question of when large meteor impacts happen once every 60 to 100 million years we're due for one soon perhaps if we want to survive we need to prepare we must find the asteroids determine and

if they're heading for earth then stop them that's not easy but it may be possible happily there's a difference between us and dinosaurs we have telescopes and we can get advanced notice of an impact asteroids are much smaller than stars and planets it's hard to see them coming to track asteroids you need a giant telescope like the aasbo observatory in Puerto Rico right now I'm on top of the largest telescope in the world and this place may actually be our best defense against getting hit by one of these near Earth asteroids the vast bowl is

1,000 ft across and it's not only the world's biggest telescope it's also the world's biggest radar dish when you think about using radar to keep track of all the airplanes that are up in the sky well this one is so powerful it can actually track near Earth objects millions of miles away unlike a telescope radar can directly measure an object's distance and reveal exactly where it is that's perfect for tracking asteroids in 2004 astronomers spot a stadium sized asteroid heading toward Earth its name apus after the Egyptian God of destruction the day it might hit

us April 13th 2029 Friday the 13th [Music] apus was the first neear object of the modern era that had astronomers honestly scared there seemed to be a 1 in30 chance of something catastrophic happening aasbo Springs into action against the biggest threat from space ever detected apus could devastate entire countries but the asteroids path is still uncertain it might hit or it might just miss only arbo can tell us for sure the arbo telescope was able to reduce the uncertainty of apus by 98% it told us that there was no chance this thing would hit us

in [Music] 2029 it will be close apus will pass closer to the Earth than the Moon closer even than some Communications [Music] satellites we have powerful tools to detect asteroids someday we'll find one that will hit the Earth how can we protect ourselves the obvious strategy is to destroy the asteroid before it destroys us but that could be risky you don't want to blow it up because you may end up breaking it into two or three or five pieces which then end up hitting all around the earth and wiping out many many people exploding an

asteroid could cause more harm than good better to make it Miss completely when an asteroid is headed for Earth their Fe future paths cross and they'll both reach that point at the same time imagine the Earth is a freight train and the asteroid is a car both heading for a railroad crossing if they reach that Crossing at the same time they will collide the best way to avoid the impact Act is not to Swerve away from the train it's to hit the gas or the brakes if you can cross the tracks before the train gets

there or wait for the train to pass and then cross them that's what we want to do with asteroids just to make sure that the asteroid and the Earth aren't at the same place at the same [Applause] [Music] time by simply slowing down the car with going to miss that's the way to avert a [Music] collision but asteroids don't come with brakes we need another way to change their speed one approach is to use the asteroids gravity for a small enough asteroid all you need to do is Park a large spacecraft next to the asteroid

a spaceship would hover above the asteroids surface you can thrust with your spacecraft to keep it from falling onto the surface of the asteroid and so it's like a little gravity tractor using gravity as the tow line to move the asteroid out of the way over time the gravity between them would slow down the asteroid just enough for it to miss the Earth asteroids could shape our future in another way way we could turn them from a deadly threat into a precious [Music] resource asteroids are a creative Force they build planets they bring water but

they're also destructive asteroids are both a boon and a threat early on they bring the materials for Life later on they can destroy life asteroids bring violence and death but life may not always be in danger ultimately if life becomes intelligent enough it can send objects out to deflect or destroy the impending asteroids we now have the technology to divert asteroids that means we can treat them not as a threat but an opportunity we could mine them many of them are just ripe for the taking in these wonderful mineral resources and so the asteroids in

some ways are are literally gold mines in the sky they're not just gold mines they're zinc mines aluminum mines Platinum mines just one average sized asteroid could contain minerals worth thousands of billions of dollars but first we have to reach the asteroids on April 15th 2010 President Obama announced a new plan by 2025 we expect new spacecraft designed for long Journeys to allow us to begin the first ever crude missions beyond the moon into deep space we'll start by sending astronauts to an asteroid for the first time in history ironically the easiest asteroids to reach

are the same ones that threaten the Earth as they pass by a spaceship could rendevu with the asteroid yet even when asteroids come so close asteroid mining may be too good to be true the reason why we're not mining the asteroid belt today and letting the Space Program pay for itself is because of cost it takes an enormous amount of Rocket Fuel and expertise to bring back an asteroid from out of space but perhaps we don't need to bring the mineral RS back to Earth we could use the resources of asteroids to build settlements out

in space you don't have to build a space station it's already there you don't need shielding because you can simply drill right into the soil and use the rocky material as shielding against radiation and microm meteorites so in some sense think of an asteroid as a readymade space station low gravity makes it easy to come and go there's plenty of water and all the construction materials that colonizers could ever need so one day when we have colonies in the asteroid belt and we need to build cities there that's where we're going to find valuable deposits

of metals in the asteroid Bel itself a vast band of cities in space strung across a billion miles and not just cities but factories to turn metal from the asteroids into spaceships perhaps asteroids could actually provide the metal the real structure to build our spacecraft so somewhere up there between Mars and Jupiter there may be the makings of our future spaceships ultimately asteroids may be a stepping stone by which we can one day leave the entire solar system asteroids made the Earth perhaps they even brought life here and in the future asteroids could help humans

escape the Earth and colonize the Galaxy so in a way asteroids are drawing us out into space whether to protect ourselves or to expand where we live this is our solar system eight planets more than 150 moons billions of space rocks dust and gas all orbit a single star in a giant whirling disc 10 billion miles miles across it's been this way for 4 billion years everything moves round in an orderly fashion Serene and [Music] stable but our solar system is unusual elsewhere in our universe orbits are nothing like this they're unstable chaotic even destructive

even in the nearby Universe we see incredibly violent examples of orbits giant planets that hurdle in toward Their Stars we see shock waves of thousands of degrees perpetuate through the atmosphere there are planets that dip right over the surfaces of other stars huge Stars orbiting each other multiple orbital systems where there's just chaos and entire objects can be kicked out of the system Stars gobbling up other stars black holes eating up entire star systems galaxies colliding with other galaxies that's the norm Earth is an oasis of water and warmth life flourishes because of how we

orbit the [Music] sun Earth's orbit is almost circular we stay about the same distance from the Sun all year round the temperature here is relatively constant and Earth's orbit has been stable for the past 4 and a half billion years without this stability we would not exist to create DNA out of the oceans takes hundreds of millions perhaps even a billion years and for that stability you need circular orbits and so without the stability of the solar system and the Earth's orbit there's no life on Earth we owe everything to Earth's orbit we get a

gentle ride in an otherwise violent Universe we've hit the orbital jackpot yet chaos is never far away even within our solar system there are extreme and violent orbits where life could never survive Mercury the closest rock to the sun and the smallest planet in the solar system its orbit stretches into an oval shape at its furthest point mercury is 43 million mil from the Sun but at its closest point it's just 28 million this close in it's hot 800° F hotter than a Baker's oven also because there's very little atmosphere on Mercury you'd choke and

because there's no air to speak of the blood in your body would boil and it would burst your skin you would literally explode on the surface of mercury but the temperature can also fall to 300° below zero three times colder than the coldest place on Earth mercury has the most extreme temperature variations of any planet in the solar system but it's also proof that orbits don't just loop with each revolution around the Sun Mercury's path shifts over thousands of years the planet follows a daisy pattern at the other end of the solar system there's Pluto

4 billion miles from the Sun the further away an object is the slower its orbit Pluto takes 248 years to complete a single Loop and Pluto is an anomaly its stretched orbit is on a completely different plane from the major planets and it creates an amazing spectacle during most of its orbit Pluto is a frozen block of ice and rock but as it gets closer to the sun summer begins when Pluto warms up the Frozen IES on the surface of Pluto these are water IES carbon dioxide even some carbon monoxide uh maybe methane IES they

evaporate and you get a fog and the fog gets thicker and then you get thick clouds and suddenly you have an actual atmosphere around Pluto that wasn't there before this atmosphere is thickest when Pluto is closest to the Sun Sun but as the planet heads back into deep space the temperature plummets to 400° below zero it begins to snow flakes of Frozen nitrogen and [Music] methane as winter comes these gases slowly begin to freeze out of the atmosphere they may rain down in a snow likee way but gradually they accumulate sort of a glassy semi-transparent

layer a frozen atmosphere on the surface of Pluto after a bitter winter Pluto drifts closer to the Sun and the 248e cycle begins again extreme changes like these remind us how lucky we are that Earth's orbit is stable in the [Music] nine but it's a delicate balance the smallest change could kill us all if Earth's orbit were closer to the sun we would be like our closest neighbor Venus Venus is a pretty good example of what might happen to the Earth if our orbit shifted a little bit in from where we are now Venus has

this hugely thick atmosphere that traps all of the Heat and the surface is close to 900° if we moved even just a little bit closer to the sun we would become more like Venus oceans would boil away our planet would become a desert life would be destroyed a small shift in the opposite direction and instead of boiling we'd freeze you would have snowball Earth the Earth completely encased in ice and that's only by moving the earth a fraction of its distance from the Sun the polar ice caps would EXP sand oceans would freeze a permanent

Ice Age would begin the smallest shift in Earth's orbit and we die by fire or ice orbits allow life to flourish but they can also cause chaos orbits are even capable of destroying entire [Music] Stars our planet's orbit makes life possible but most orbits are violent space is a cosmic freeway nothing stands still everything moves around everything else thanks to a single Force gravity gravity is the universal force of attraction that spreads throughout the universe itself it's the force that holds stars together it's the force that binds the solar system together all objects have gravity

so all objects attract each other the more mass an object has the stronger its attraction that's why falling apples are pulled toward Earth in our solar system the biggest object is the [Music] sun it's 700 times more massive than all the planets put together the Titanic force of the Sun's gravity pulls all the planets inward but something stops them from falling in the planets are in constant motion they fly through space at incredible speed not directly toward the Sun but sideways creating a tug of war between the Sun's gravity and the planet's speed when the

two balance out the planet loops around the sun we call this an orbit an orbit is simply the motion the path of an object around another object due to gravity so you can have circular orbits you can can have elliptical orbits even if I were to take a ball and throw it in the air and catch it very briefly that ball is in orbit around the center of the earth it's just motion affected by gravity imagine what would happen if the sun had no gravity the planet speed would shoot them out into space on the

other hand if the planets stopped moving gravity would pull them into the sun [Music] all orbits are a balance between gravity and motion we like to think the universe runs like clockwork everything neat and orderly the planets moving in Cosmic Harmony but that's wrong orbits can be wild and unpr predictable and the more objects there are the more unpredictable their orbits become things can get complicated when you have more than two objects all trying to orbit around each other then an orbit can actually Loop between one object and another speeds can get faster and slower

and orbit doesn't have to be just one regular path the universe's creativity defies the imagination travel out Beyond Pluto halfway to the nearest star and you find these comets chunks of ice and rock they float in vast clouds Frozen remnants from the dawn of our solar system every so often one Falls towards the sun they can start a trillion miles out and fall right above the surface of the Sun so when they're really far away they're hardly moving at all when they're whipping past the sun they're moving really really fast and so these can be

some of the most extreme orbits in the solar system they can be so elongated they're almost a straight line comets travel at up to a million miles an hour they're Cosmic missiles Guided by gravity and speed comets show us how destru Ive orbits can be many plunge into the Sun or crash into planets if a comet were to hit the earth perhaps 5 six miles across watch out it would be a planet Buster it would be an object sufficient to wipe out all Life as we know it on the planet but most comets Miss they

fly in from deep space and out again on million-year orbits but move beyond our solar system and orbits become even more violent death spirals rip apart entire planets shred stars and even tear holes in space the universe is unimaginably Big so there should be other earthlike worlds out there scientists looking for habitable planets thought they would find orbits just like ours they were wrong so now we're on HD1 15488 and there it is looks good we have discovered hundreds of planets outside our solar system but they're not like Earth at all these are strange alien

worlds with unfamiliar orbits what we're finding among extrasolar planets is an incredible diversity of these orbital shapes and sizes some of the orbits are extreme ex ly tight around their host star the planet going around in just hours or days so we're seeing interactions and shapes and sizes of orbits that are like nothing we ever [Music] imagined some worlds are so hostile Life as we know it would be impossible this is wasp 18b it's a hot Jupiter a class of huge planets that closely orbit their Stars wasp 18b is 50 times closer to its star

than we are to the sun it's so close it orbits in less than one [Music] day if you had said what's the weirdest least likely orbit you could possibly imagine I would have said take something like Jupiter and plop it down right next to a star 5 million miles away and it turns out I would be totally wrong that is an extremely common thing that we see in the universe in fact most of the planets that were're discovering around other stars appear to be in orbits like that this Cosmic duel produces incredibly powerful physical effects

wasp 18b Burns at 4,000 de thermal hurricanes blast across its surface and both star and Planet are distorted by by vast gravitational forces the same forces that cause the tides on Earth everybody is familiar with the idea of tides in the course of a day the level of the oceans get higher and then lower well that's from the influence of the Sun and the Moon from the influence of orbits things that are going around us or that we're going around if you bring things closer together Tides become more extreme planets can actually get pulled into

different shapes wasp 18b was formed in a cold region of space far away from its star over millions of years it spiraled into its present position it's locked in a gravitational battle that can only end one [Music] way less than a million years from now it will be consumed by fire the key conclusion you have to draw is when you see the universe today it won't be that way tomorrow and it won't be that way the week or the Millennium or or a billion years later because of gravity our search for earthlike planets reveals a

destructive Universe from the deadly missil likee orbits of comets to the Searing Paths of hot Jupiter's there are even planets that don't seem to orbit anything at all scientists have recently detected tiny fluctuations in the light from distant Stars the only explanation a massive object between us and Them these rogue planets don't orbit a parent star they are planetary orphans all alone in space Planet SP definition go around Stars so boy were we shocked to find rogue planets rogue planets are a contradiction in terms planets without a mother star scientists think every Rogue planet did

once orbit a star until gravity hurled them away new solar systems are chaotic places planets tug on each other and dramatically change course some planets even spiral out to wander the Galaxy alone the presence of rogue planets shows us that gravity is not just this attractive Force which binds the solar system together it can also fling entire planets into outer space a recent Sky survey suggests our galaxy contains more rogue planets than Stars we've discovered orbits we didn't even know were possible gravity and motion keep our universe in constant turmoil vast orbiting Suns cannibalize each

other violent vortexes distort space itself and Powerful forces flick a star like a spinning top gravity causes this chaos on an epic scale hurling planets to their destruction or firing them off into space but the cosmic roller coaster gets even more extreme orbits become so violent they rip chunks out of stars this is hm can cre a binary star system 16,000 light years from Earth they're white dwarfs small but incredibly dense one teaspoon of white dwarf matter can weigh 5 tons the stars are just 50,000 M apart five times closer than we are to the

Moon they orbit at more than a million miles an hour we have two white Shores an infimal distance apart rotating around each other in 5 and 1/2 minutes this is a world's record for an astronomical Body In Space the forces are immense gravity rips superheated gas out of one star and slams it into the other scientists believe this orbit is so violent it warps the fabric of space at self in the process the Stars lose energy falling even closer eventually they'll Collide creating a [Music] supernova a supernova is one of the most violent energetic events

in the universe today you are blowing up a star there's no way to describe that kind of energy some supern noi are so powerful they are second only to the Big Bang itself for energy and sheer power they are so magnificent they can outshine an entire galaxy of 200 billion stars supernova can create one of the weirdest objects in the universe a pulsar Pulsar are intensely magnetic Stars they fire out beams of electromagnetic radiation that sweep across space there are few things in the universe more dramatic than a pulsar imagine a ball about 10 Mi

across rotating hundreds of times a second with a density that's almost unimaginable 1 cubic centimeter of this material would have as much mass as Mount Everest you would feel a gravity that is millions millions of times what you're feeling sitting on the surface of the Earth you wouldn't just be crushed flat by this you would be crushed into a pce that is only a few atoms thick anything that orbits a pulsar too closely risks being torn to shreds this is the Black Widow pulsar it rips through our galaxy at 600,000 M an hour the shock

wave is so vast our telescopes can detect it 5,000 light years away traveling alongside it a brown dwarf bigger than a planet smaller than a star the pair are locked in an orbital Dance of Death the Black Widow in some sense is like a vampire sucking the lifeblood from this brown dwarf star eating away at its hydrogen and helium fuel radiation blasts the brown dwarf's gases into space a pulsar just 10 Mi wide is destroying an object bigger than Jupiter eventually the brown dwarf will evaporate a single pul has immense destructive power but two pulsars

together can change the shape of the universe this is the only known double Pulsar system in our galaxy orbiting at 700,000 mph their speed and mass make them spin chaotically it's incredible to think of the enormous forces uh gravitationally that these two stars exert on each other causing the whole geometry the architecture of the system to change and spin around like a top on the table the gravity of the heavier Pulsar makes the smaller one wobble erratically it whips around so violently that the whole star almost tips over just like a spinning top it can't

last forever 85 million years from now the two pulsars will merge to form a vast gravitational Abyss the universe's ultimate monster a black hole a black hole the most extreme object in the universe at its Center the laws of physics break [Music] down time comes to an end gravity is infinite a black hole is a bottomless pit of gravity caused by the death of a star there is nothing in the universe more mysterious than how black holes work if you want to talk about extreme orbits and extreme gravity you're talking black holes that is at

the top of the list nothing has stronger gravity than a black hole it is the mass of something like the sun or more compressed down into a ball that's only a couple of miles across 50 years ago black holes were dismissed as science fiction but not anymore now we see them at the center of galaxies wandering through outer space black holes we now know are Central to the evolution of the universe we now think there may be a 100 million black holes in our galaxy alone an encounter with any of them leads to Oblivion this

is one of the largest and hottest stars in the universe it's 20 times more massive than our sun and 10 times [Music] hotter stars like this never live long but this one is locked in a diabolic wall trapped in the grip of a black hole the gravity here is so powerful the star orbits at half a million miles an [Music] hour the black hole sucks the Stars outer layers into a vast swirling disc a disc so hot it blasts out x-rays a million times more powerful than our sun this configuration a star orbiting around a

black hole is Extreme and it's unstable first of all the black hole is eating away at the atmosphere of His companion star but the star itself is unstable it will one day undergo a supernova and perhaps leave a black hole in its wake and then we'll have two black holes rotating around each other one of the rarest sites in the [Music] universe eventually these black holes will merge to create a new larger monster and the cycle of Destruction will continue but this black hole is small other black holes take violence to a whole new level

in 2011 astronomers witnessed one of the biggest EXP explosions ever recorded a flash of radiation brighter than a 100 billion Suns a gamma ray burst it was a spectacular event the burst came from a super massive black hole at the center of a distant Galaxy it had been dormant but something had shocked it back to life if you pass by The Event Horizon an imaginary sphere surrounding the black hole that's the point of no return it's like the ultimate Ro Motel everything checks in nothing checks [Music] out several stars were orbiting the black ho hole

at a safe distance then one of them got too close the sleeping giant suddenly awoke immense gravitational forces stretched the star to its breaking point until finally it was torn apart debris swirled around the black hole heated to millions of degrees two giant jets of gamma rays blasted into space at the speed of light a black hole has torn a star apart swallowed up half of the material of the star and ejected the other half in an event that is among the most violent things we have ever seen in the history of astronomy the event

was so violent we saw it from Earth 3 billion light years away black holes can suck in planets and rip apart stars but gravity doesn't always pull things in any high school student knows that gravity sucks it pulls it never pushes but it's actually more complicated that's true when you just have two objects but the minute you have more than two objects strange things can happen and gravity can actually push you away you can get very close to a body but if you come in at just the right angle and just the right speed instead

of colliding together one object can slingshot the other one away recently scientists discovered Stars hurtling away from our galaxy at incredible speed normal Stars don't do this so what could accelerate a star to hyper velocity the answer was a surprise you can only eject stars at these very very high velocities so close to 700 800 1,000 km a second you could only eject these with interactions with the super massive black hole each hypervelocity star was originally one of a pair of stars orbiting a super massive black hole when they got too close gravity pulled them

apart the black hole catapulted one star out of the Galaxy at 2 million miles an hour eventually the other was sucked in and destroyed the interesting thing here is that you can get a complete redistribution of stars so you have stars that are in the center of the Galaxy and suddenly they're ejected out into Intergalactic space and it's out here in deep space that orbits are at their most powerful smashing entire galaxies together to create the structure of the universe itself [Music] Across the Universe extreme gravity is a force of Destruction the orbits of planets

and stars can be chaotic unpredictable and violent but on a truly Cosmic scale gravity is no longer just a destroyer it also creates new worlds these galaxies giant spinning clusters of stars gas and dust a 100,000 light years across galaxies orbit each other in the same way planets orbit Stars gravity pulls them together their speed keeps them apart but ultimately gravity always wins entire galaxies smash together one of the most spacular events in the universe is when galaxies Collide you're talking about hundreds of billions of stars 100,000 Lighty years across two of these things slamming

into each [Music] other collisions between orbiting galaxies take place over millions of years gravity slowly pulls them together and you get these two galaxies that merge like two fluids mixing together and you get long tidal Tails as they pass through each other but then gravity brings them back together again and in the end you get a full-fledged more mature larger Galaxy than you had [Music] originally on this Intergalactic scale gravity and motion are no longer destructive forces now they trigger the creation of life itself you would think a galactic Collision would be incredibly destructive and

in one sense it is but in another sense it's a very creative [Music] Force colliding galaxies smash vast gas clouds together huge shock waves rip through them squeezing the gas then something amazing happens the birth of countless Stars it's incredible to think about two galaxies that gravitationally attract each other and Collide what could be more destructive but in fact there's a power of construction in such mergers because as two galaxies come together the gases are compressed and sometimes the gases are compressed so much that you get the birth of stars and the associated planets around

those stars and so in the Titanic collision between two galaxies you can get the birth of stars and planets and perhaps eventually life on those planets sometimes these collisions trigger a chain [Music] reaction two spiral galaxies in mid Collision creating stars and [Music] planets but this time there's a [Music] difference some of these new stars are massive unstable and short-lived they explode each explosion blasts out new shock waves and triggers the birth of even more stars astronomers called this a starburst it's the ultimate example of gravity's creative power a starburst Galaxy is one that is

creating stars at a much higher rate than we usually see in normal galaxies and so it's amazing that you can have such a a beautiful creative process coming out of something so violent and destructive gravity and motion the two forces that give birth to every new star also weave together the fabric of the universe [Music] itself our Cosmos is not random it has structure the universe is a vast three-dimensional tapestry each of these threads and filaments contains billions of galaxies it's the scaffolding that holds everything together the cosmic web and we think about scaffolding of

a building it's just sitting there static but in fact this scaffolding is quite Dynamic and quite amazing because all of the constituents are moving around at very high speeds crashing into one another galaxies Stars black holes supern noi all in this uh tremendous Cosmic Dance The Cosmic web is incomprehensibly vast each thread is full of motion galaxies form orbit and Collide countless billions in a constant stream every filament is a galactic freeway with an endless flow of traffic each point of light a Galaxy it's Rush Hour 24/7 and sometimes there's gridlock every billion light years

several filaments join to form a knot whole clusters Collide to form some of the largest structures we know of super clusters this is one of them able 2744 five orbiting Galaxy clusters crashed together in the single biggest Cosmic pile up ever [Music] discovered gradually the five clusters merged and fused to form a single giant super cluster 6 million light years across the incredible power of orbits can literally tie the universe in knots structures in the universe have evolved over billions of years through their their orbits and their Mutual gravitational attraction and they've built up into

larger and larger structures and it's all thanks to these same attractive forces that that bring them together but can also tear them [Music] apart again and again we discover orbits dominating the cosmos the atom is the basic unit of chemistry in the same way the orbit is the basic unit of the universe itself if you understand all possible orbits you understand the Dynamics driving the universe orbits have created a cosmos full of richness and complexity orbits are changeable they're chaotic things that we never thought were possible are in fact possible from the smallest scale to

the largest scale it's the gravity ational interactions and collisions that actually make our universe the beautiful place that it is and behind it all is a curious Paradox a dramatic streak of light across the sky a passing comet is an astonishing sight they're beautiful these fuzzy glowing balls with the tail coming off it's really something you just don't get to see an object like that very often comets are extraordinary if you get to see a comet for the very first time it'll stick with you forever the Journey of a comet as it sails through the

solar system is the most fantastic of all astronomical objects it Loops in toward the Sun from from the depths of space an odyssey that can last millions of years many pass by the Earth so often they're almost like old [Music] friends every comet is a frozen mass of rock and Ice several miles across but all we see is a glowing ball of light and a long sweeping tail yet comets are more than Cosmic fireworks they could help unlock some of the deepest mysteries in science we're trying to figure out as scientists where we came from

and and that means everything from the beginning of the universe to the beginning of the solar system to how life started comets really really fit into that they really give us clues about how the solar system formed if we can't understand comets we don't understand how we got [Music] here comets may even be the source of life [Music] itself we may owe our existence to the fact that comets billions of years ago came to Earth and and brought the necessary ingredients for life they can also cause enormous destruction [Applause] [Music] comets could kill us all

if a comet were to hit the earth watch out it would be a planet Buster it would be an object sufficient to wipe out all Life as we know it on the planet learn about comets and just maybe we will learn how to survive them and begin to understand how the universe works when we study them we're learning what the solar system was like when it was first forming and we can learn about what other solar systems were like as well and hopefully that will teach us a tremendous amount about how stars form and how

planets form and and how comets themselves were originally formed comets date back to the birth of our solar system 4 and a half billion years [Music] ago they were made by the same force that created the solar system gravity it began in a melstrom of chaos a giant cloud of gas and dust collapsed to form a whirling disc [Music] close to the Sun it was burning hot but further out it was cool enough for gas clouds to condense and Freeze Ice Crystals fused with grains of dust they slowly pull together into larger and larger masses

over time these sort of snowball like a snowball rolling downhill picking up more and more and more material eventually they formed gas giants like Jupiter and Saturn but not all the debris in the dis turned into planets trillions of lumps of dirty ice were left behind the Comets you could almost think of comets is sort of the Frozen leftovers of the uh the formation of the solar system they are almost unchanged to this day there are pristine time capsules and if you could crack One open and see what was inside you could literally see what

the solar system was first made out of that's remarkable but the Comets did not stay put several hundred million years later the solar system plunged into turmoil once again encounters with debris pulled the gas giants out of position the Giant immense gravity then hurled comets in every direction flinging trillions of tons of material from the dawn of the solar system into the cold outer reaches of space some comets settled in a region 4,000 million miles from the Sun the Kyper belt but most were tossed even farther out to form a giant sphere around the entire

solar system we call it the ort Cloud this is a region of our solar system that's farthest away from the sun the sun is just a tiny little dot one of many stars and the whole area of space around you is virtually empty there's nothing there very little and just occasionally you'll find the odd Comet floating out there in deep freeze cold dark and very much alone in this remote ice Cloud there are more than a trillion comets they can take millions of years to orbit the Sun but they don't always stay here the orbit

of every comet is a delicate gravitational balance the smallest nudge can tip the scale most comets spend their entire lifespan billions of miles from the Sun motionless inert simply waiting for something to happen but then perhaps a random Collision takes place perhaps a passing star nudges it and then the gravitational force of the sun inevitably pulls it toward the inner solar [Applause] [Music] system Gravity the force that created the Comets then flung them to the edge of of the solar system now pulls them back in our Comet begins its epic aicy to spread life or

death across the solar system more than a trillion comets Circle the Sun at the Frozen edges of our solar system but many do not stay here the smallest gravitational disruption can knock them out of their orbit it could be a nearby star going by it could be us going through a denser part of the Galaxy anything that just gives a little gravitational hit to a comet can cause it to fall in towards us our comet has been Disturbed now the sun's immense gravity takes [Music] over you can think of the gravity of our solar system

sort of like being a hillside at the bottom there's the Sun and comets are way at the top of that Hill when they get dislodged there's only one way for them to go they have to fall down in towards the [Music] sun our Comet accelerates towards the Sun but its path is far from straight Gravity from the planets can throw comets off course or out of the solar system completely if they escape these obstacles comets continue continue their journey toward the sun now they begin one of the most remarkable Transformations known to science a Crysis

to a butterfly they they become the most spectacular things the universe has to offer as it passes Jupiter our Comet begins to [Music] change as it starts to move a little bit faster and starts getting closer and closer to the sun and it starts feeling the heat of the sun that's when things really start to [Music] change 500 million miles from the Sun heat brings our Comet to life Frozen gases start to vaporize grains of ice and dust rise from the [Music] surface as the comet continues to approach the Sun and gets warmer more and

more gas is released the comet becomes a fuzzy ball there's a solid part in there but it's surrounded by a much larger sort of cloud of material this cloud of dust and gas forms an atmosphere or coma around the comet and it also creates the comet's huge tail it's all driven by the Sun and it's not over yet there's something called the solar wind it's actually a huge wave of charged particles originating from the Sun this fills our solar system and as a comet begins to move further and further in towards the Sun the solar

wind gets stronger like a cosmic hurricane the solar wind blasts gas molecules from our Comet out into space they form a second giant [Music] tail the solid part of the Comet might only be a few miles across and the fuzzy part might be a few thousand or tens of thousands of miles across the tail that gets swept back as that material is blown off by the solar wind can be millions or tens of millions of miles long our Comet hurdles through space at 50,000 M an hour it's about to enter the most violent phase of

its Journey 200 million miles from the Sun Water Ice begins to vaporize the ground would start to shift and Quake and as the material beneath my feet is literally thawing we'd have great big jets of carbon dioxide and water ice starting to come out and that would not be a very good place to be standing the surface cracks open gases explode debris fires in all directions the force of these eruptions makes the comet tumble erratically every jet that turns on is literally like a little jet engine attached to the comet like a dragster on a

racetrack our Comet explodes to life incredible speed irresistible energy and a vast plume of debris our Comet transforms into a cosmic hot rod but speed and energy are a volatile mix our Comet could blow apart at any moment the cloud around our comet is now bigger than Jupiter its tail stretches for 100 100 million miles an object 4.5 billion years old emerges from the dark every arrival of a new comet is like a gift from the universe we've never seen this little bit of the solar system before this little building block this little baby picture

it's completely new to us it's a chance to study the origin of our solar system and what we're learning is a revelation comments are far more hostile and alien than we [Music] imagined with modern telescopes we can study comets in more detail than ever before but to really understand them we need to get close to the very heart of a comet it's nucleus one of the Holy Grails of comet science is to really understand what is in a comet's nucleus what is actually on the surface what is the chemical composition what are the characteristics of

the rocks and the materials the volatiles that are on that [Music] surface the nucleus is the fundamental building block of the solar system that we as scientists really want to investigate that's where the Mysteries really are there have been more than a dozen missions to comets in the past three decades every one of them has been a revelation we've learned about the chemistry of them we've learned about the physical interaction they have with the sun we've learned about their physical surface their terrain and how they're different even if you were to go from one spot

on a comet to another so we're really learning that these things are worlds unto themselves scientists thought comets were white like a snowball that changed in 1986 when the jotto space probe beamed back these images of Hal's Comet for the first time in history we had a snapshot of the very center of that Comet that Comet that entered human history on many occasions and we found a cold dead world we found an object shaped like a Peanut Hi was no snowball a thick layer of black dust covered its surface there were pits and hills and

hi was 9 mil long far bigger than anyone expected scientists thought that all comets were the same they were wrong in 2004 the Stardust probe flew into the tail of comet Vil 2 and captured thousands of tiny dust particles when Stardust brought those samples back on Earth we realize that in fact every comet is a unique object just like every planet is different it looks like every comet is different it has its own history to tell different materials went into its formation different heat sources were injected into its interior I different chemical processes and geologic

processes occurred each one is a unique World waiting to be explored some comets are truly strange these are real images of heartley 2 a comet so weird it snows it's so strange we were able to see that there are golf ball siiz ch chunks of dry ice that are following the comet around up to a million miles away from the nucleus this thing is just making a big mess AR too is just amazing it looked like you were in the middle of a snow globe and you shook it up and there all these little things

kind of like flies buzzing around food just kind of floating out there it's just not right heartly 2 is a hyperactive Comet it tumbles faster and spits out more debris than most others its size comets are alien worlds on Comet Temple 1 there are smooth plateaus craters and cliffs 60 ft High layers of rock lie on top of each other like a stack of pancakes each Comet seems to have its own unique history temple one gave scientists their biggest breakthrough in 2005 the Deep Impact space probe slammed a projectile into its surface the explosion dug

out a crater 150 yd across talk about a spectacular Fourth of July I mean can you imagine anything better we actually blew a hole in a comet I mean that's got to be one of the more amazing things that NASA has ever done the material the impact ejected allowed us to see inside a comet's nucleus for the first time it was completely unexpected we found things like rubies and parido gemstones tiny little things inside the comet and we found all kinds of organic molecules the very sorts of things we're made [Music] of scientists now believe

that comets play a critical role in our universe where do the ingredients of life come from where were they all mixed together where did all this liquid water come from comets could hold the key to understanding the nature of life itself but opportunities to study them up close or rare our comet is now moving at incredible speed toward a place where no spacecraft could ever survive the sun 4 billion years ago gravity hurled comets to the edges of our solar system the same force can pull them back in our Comet passes Earth and enters the

most violent stage of its Journey it Rockets toward the Sun at 100,00 ,000 mph the surface of the comet is now sizzling sizzling with activity blistering temperatures are being created enormous geysers of ice cryle and gas being shot off the surface jets are erupting all over the place it's tumbling the rotational state is changing and the Very surface is kind of cracking up underneath our feet inside the comet pockets of gas explode and Flame huge rocks into space it's losing mass it's shrinking and as we get closer and closer to the Sun and more and

more of the volatiles are starting to come off of its surface this can actually change the rotational state of the Comet can make it tumble can actually even push it in its orbit it can actually change the orbit of the Comet comets Can Shed 50 tons of ice and gas every second enormous pressures built up inside the nucleus it could become unstable it could even can break apart into pieces at any time as comets reach their closest point to the sun their existence is on a knife edge many will not survive we've been able to

actually see images of comets just getting swallowed up by the Sun and you can actually see them just pelting in there and the whole body whether it's a mile across or 10 mil across just gets completely and utterly destroyed a solar Observatory recorded these extraordinary images they show small comets called Sun grazers diving towards the sun here they're exposed to immense gravity and torched by the Ferocious Heat Of The Sun many are vapor IED even in deep space vast explosions can tear comets apart in 2007 Comet Holmes was heading away from the sun when something

extraordinary happened in less than a day it grew half a million times brighter the cloud around it ballooned into space it's actually relatively common for a coma the fuzzy part around a comet to expand large enough to be bigger than Jupiter a 100,000 miles across but that can take days and weeks and months to build up to have a single event something that happened boom all at once some catastrophe to create this shell around Comet homes that could be bigger than Jupiter is amazing to me we had never seen something like this before in fact

the co of the Comet was actually larger than the sun itself briefly it was the largest object in the entire solar system something that was unprecedented without warning Comet Holmes blew apart the largest cometary explosion ever recorded the debris stretched for a million miles what caused it is still unclear one theory is that perhaps Comet Holmes slammed into an asteroid of some sort creating this gigantic Mega Flare in out of space another possibility is perhaps the comet was unstable and perhaps there was an explosion caused by expanding gas and ripped the entire Comet apart at

the present time we simply don't [Music] know the life of all com hangs by a thread our Comet survives its encounter with the Sun but it's paid a price its geography has been totally rearranged huge trunks mountaintops worth of rock have disappeared an object which could be perhaps 10 20 mi across has lost literally hundreds perhaps thousands of tons of rock and ice on its journey and as our Comet leaves the sun behind activity on its surface subsides on its outward Journey a comet gradually begins to shut down it becomes cooler less active the Jets

begin to turn off the coma begins to blow away and you're left with this little ball of ice and dirt it returns to the depths of space dormant once again but the sun is just one of many challenges comets must also survive the gravitational pole of the planets our gravity is way too small to have any effect on this Comet but Jupiter is a very large planet it has 300 times the mass of the Earth if the comet passes within even a few million miles of Jupiter that can change its orbit the consequences can be

catastrophic in 1994 a comet called Shoemaker levy9 flew too close to Jupiter scientists watched the planet's immense gravity tear it apart the remains headed straight toward Jupiter many people thought that the impacts wouldn't do anything to Jupiter that Jupiter would just sort of swallow it up without a burp and that's not what happened at all 21 Comet fragments smashed into Jupiter's atmosphere each impact released more energy than all the world's nuclear arsenals combined Comet shmaker Lev 9 was not a particularly massive Comet and it wasn't even a very dense one it actually had the consistency

of cotton candy you could have pulled bits of it apart with your fingers but this rather tenuous little icy creature created unimaginable destruction the impacts hurled plumes of debris thousands of miles high and scarred Jupiter's atmosphere with dark lesions the event rocked the scientific Community to actually see it for ourselves to actually see the immense destructive Power by an object that's really not that much bigger than a hill was really pretty terrifying even though we knew the math to see it for ourselves was amazing the Shoemaker le9 impact really woke astronomers up to the fact

that impacts can happen now and they can happen here if a comet just a few miles across hit our planet the result would be catastrophic tidal waves would devastate the land debris Would Rain from the [Music] sky Life as We Know know it would end yet Comet impacts can also be a creative Force they could even trigger the birth of life itself [Music] Across the Universe comets cause massive destruction they could be moving 50 or more times faster than a rifle bullet and you were talking about something the size of a mountain so the amount

of energy that this thing would release upon impact is devastating but they're not always destructive they have another side scientists believe they can shape entire worlds this is Titan the largest of Saturn's moons it's the only moon in our solar system with a thick atmosphere rivers and lakes of liquid methane cover its [Music] surface Titan was transformed by comets radar images reveal feel a moon shaped by a blizzard of comets that rained down over millions of years each Comet vaporized when it hit releasing gases from inside its nucleus gradually they built up a rich organic

atmosphere and this strange liquid landscape comets turned a space rock into an earthlike world comets in some sense are the ultimate Engineers of the solar system cometary impacts could give us the chemicals which give us the atmosphere not just of Titan but even perhaps the Earth itself so if comets have the power to reshape entire worlds what part did they play in the history of our own planet to find out we need to get closer to a comet than ever before we need to land on one in March 2004 the Rosetta Mission launched the Rosetta

mission is named after the Rosetta Stone because just like the stone gave linguists the keys to the ancient language we're hoping that the comet will give us the keys to understanding the ancient solar system November 11th 2014 will be a landmark in space exploration for the very first time a spacecraft will touch down on the surface of a comet previous missions to comets were basically flybys and they basically give us tantalizing evidence that there was a greater mystery yet to be solved now we're going to land on a comet we're going to be up close

and dirty with the live Comet streaming through out of space and this is unprecedented Rosetta is around the size of a car it's flying through space at 20,000 mph it's heading for this a comet with a nucleus 3 m wide orbiting the Sun every 6 and 1/2 years a robotic Lander will drop down to the surface beginning the most detailed study of a comet ever attempted it's going to look at what the surface looks like it's going to take samples it's going to look at the terrain it's going to be able to actually probe inside

the comet and see what it's made of and how it's put together where hopefully going to learn more from this Mission about one Comet than we have about just everything we've we've known about comets for for [Music] centuries Rosetta should answer some very simple questions is it porous is it like a sponge is it like a a bunch of tubes is it like a a a snowflake you know with this sort of uh fairy castle structure uh these things will help us to understand how the heat flows within and maybe what causes certain portions of

it to become a a jet and other portions not but this is just the beginning for an entire year Rosetta will study the comet on its Epic Journey around the Sun using technology so advanced IT mimics the five human senses we've got uh instruments that can see we've got a kind of an ultrasound experiment instruments that are the equivalent of your hands so we'd like to understand everything possible about this comet's Journey around the Sun from when it's quiet to when it's at its most active but we'll have to get there first just to reach

the comet scientists must overcome enormous technical challenges Rosetta must hit a Target just 3 m wide traveling at 34,000 m per hour landing on it will be even harder comets have very little [Music] gravity there's not anything that you know is going to pull you down to the surface uh and there's no atmosphere so you can't unfr a a parachute and just sail to the down until you touch down you've got to figure out a way to uh get your target your your Lander uh to actually reside and rest on the surface technicians have an

ingenious solution the Lander is equipped with shock absorbers and a harpoon when it makes contact with the surface at the same time the Harpoon will be released down into the substrate and it will have prongs that will open that will prevent it from coming back up Rosetta will attempt to solve some of science's deepest Mysteries we would very much like to know why is it that Earth has liquid water and so much of it compared to any place else that we've ever seen so how is it that the water got here now there is a

theory that says that comets delivered the water to the Earth Earth long ago but the question is can we actually prove [Music] it to find out the Lander will collect water molecules to compare with water from Earth but scientists hope to go even further we're on the brink of making an extraordinary Discovery we may find proof that life itself has an extraterrestrial origin that it was brought to Earth Earth by [Music] comets life has existed on our planet for at least 3 and a half billion years but we still don't understand its Beginnings we used

to think life originated on Earth itself that volcanic gases and water vapor formed oceans and an atmosphere lightning added the creative spark for early life to begin now we think that's wrong and the evidence is in [Music] space in 1997 Comet hail Bop appeared one of the biggest and brightest comets ever recorded scientists found it was packed with water gases and carbon the basic ingredients for [Music] life that Discovery raised profound questions we're all used to the idea that life originated here on Earth and it probably did at least complex life but where did the

building blocks come from where did the water that makes up our body the organic molecules that make up the very essence of life they actually may not have been intrinsically part of the earth to begin with they came from somewh [Music] else Hell Bop suggested that the raw materials for life might have an extraterrestrial origin since then scientists have found further Evidence astrobiologist Dante Loretta discovered that dust from Comet Vil 2 contained minerals that could only form in in heat and liquid water we had the sulfide minerals we had iron oxides we had carbonate minerals

which are the same kind of materials that marine organisms use to build their shells unlike anything we thought was possible to be formed in the early solar [Music] system scientists have even found that Comet vilt 2 contains amino acids that's incredibly exciting because amino acids are the building blocks of proteins and pl proteins are essential biomolecules for all life on Earth these discoveries have transformed our understanding of comets many scientists now believe they're more than just Frozen time capsules perhaps they play a central role in the history of our planet we have learned from study

of a single Comet and the result of the star mission that they are complex chemical laboratories where the ingredients of Life Could form these materials likely did not arise naturally on the surface of the Earth from processes on our planet instead they had to be delivered by these Messengers from the outer solar system the idea that we may owe our existence to Comet impacts is astounding but not everyone is convinced there's pretty good circumstantial evidence that a comet might have been important to life but we don't really have you know if we're CSI if we're

the comet science investigators trying to prove it we haven't got the proof lined up yet it's quite possible that what we have out there has nothing to do with Life as we know it on earth scientists hope the Rosetta Mission will resolve the issue if we can establish a correlation between amino acids on comets and the amino acids we have on Earth life on Earth um that would be one of the most significant findings in uh in science the story of life on Earth began 4 and A2 billion years ago when our planet formed it

was a Barren hostile World 700 million years later the solar system plunged into turmoil gravity ripped comets from their orbits and hurled them in all directions many into the inner solar system they rained down on the early Earth for 300 million [Music] years they released gases and organic material creating an atmosphere and the oceans finally life could begin it's a dramatic story but is it true only time is going to tell if we keep studying these mysterious objects whether or not we can really pin down exactly the mechanisms and find out how it all got

started in a 100 years time hopefully we'll look back and say wouldn't it be cool to have been a living at that time to be a witness to be one of the first to make these incredible discoveries in the meantime the search for proof continues I can't say for sure if comets brought all of these raw ingredients to the Earth and that we evolved from these materials but it's certainly possible and it's absolutely poetic to think that we came from out there [Music] [Music]