How Were Stars And Planets Formed? - Did a Supernova Give Birth to Our Solar System

from the drama of our planet's origins and the birth of our solar system comes one of the most startling revelations of modern science the solar system we see today quiet stable was once a battlefield newborn planets blasted through space competing for stable circularized orbits inside a grunge style mosh pit of gas and dust for those that find the right balance the prize is survival the rest world-shattering destruction a new look at the chaos of creation and a frightening possibility in our distant future [Music] mars [Music] the curiosity rover is searching for clues about the origins of the red planet it confirms the presence of oxygen and nitrogen isotopes hidden in the rocks and soil we use isotopes to try to figure out the history of planets partly because they are immune to many of the changes the chemical changes that occur when you have things like collisions and so forth isotopes the relative abundances of these isotopes are like fingerprints [Music] curiosity confirms a unique mix of isotope fingerprints the isotopes indicate that mars formed elsewhere in the solar system and moved into our neighborhood [Music] our solar system is full of oddities pointing to an imperfect birth and a malformed evolution all of our planets go around the sun in the same direction that the sun is spinning this is the same direction that the clouds within our original nebula began to rotate [Music] six planets spin around their poles in the same direction for them the sun rises in the east and sets in the west yet two planets spin the opposite direction for venus and uranus the sun rises in the west and sets in the east uranus not only has a retrograde spin it rolls on its side like a bowling ball at neptune the icy moon triton orbits backwards opposite from the direction of neptune's spin do these planets spin backwards because they were rocked by titanic collisions in the past so we see evidence in the architecture of the solar system for not only collisions like earth's moon and the fact that venus is is rotating in the wrong direction and uranus is on its side and so for all these things are attributed to collisions we also see in the asteroid belt and in the kuiper belt the outer asteroid belt if you like we see that the orbits of these things look like they've been disturbed [Music] closer to home our own earth has an inexplicable 23 and a half degree tilt its spin axis is radically misaligned from its magnetic pole and our moon is comparatively large for a planet our size now a new theory may be able to explain many of these oddities it is called the grand tac hypothesis four and a half to five billion years ago a gas giant planet arose inside a primordial disk of gas and dust jupiter didn't just form where it is but formed and then moved inward towards the sun as it spirals toward the sun jupiter herds asteroids and rubble [Music] jupiter's natural tendency is to drift in slowly through this debris field that it's traveling around the inner solar system is also thick with gas and dust the birth of our planetary system is well underway numerous worlds are born in this region including the earth primordial skies are ruled by chaos jupiter's approach destabilizes these planets their orbits decay into wildly swinging ellipses some are tossed out others fall into the sun their numbers are unknowable these are ghost worlds from a bygone age jupiter just causes all heck to break out in the solar system and all that debris in the outer solar system gets flung inward towards the inner solar system and it was a busy time in the very early solar system and since we're colliding with each other all the time and then it stopped jupiter's invasion of the inner solar system is mysteriously halted the planet makes a turn or in sailors parlance a grand attack [Music] lurking behind jupiter is a second gas giant saturn [Music] so as jupiter was migrating inward saturn was following it and growing and as saturn was growing it came to have a size that it had a gravitational impact on jupiter which became more important than the gravitational interaction between the gaseous disk and jupiter they reverse direction and in a sense you can think of saturn and jupiter feeding off one another and moving back out gravity tugs each passing planet this transfers orbital energy from one world to another all you have to do is exert a very subtle little periodic force at the right time and you can have amazing changes in the motion of the object you're pushing on once enough energy has been transferred the planets synchronize their orbits they are said to be in a resonance for planets resonances are achieved and maintained through the mutual push and pull of gravity through the fabric of space they're a key factor in the continuing evolution of our solar system this effect can be duplicated in the lab we have 10 metronomes here set up on a swinging platform they have little weights on pendulums here but they've all been set at the same frequency and i'm going to try to start them as best i can completely out of phase randomly so their oscillation is going to transfer energy by the swinging of this plastic sheet to the other metronomes that are out of phase to get into phase with the majority it's inevitable that there's going to be some majority group which starts out swinging more or less together and they are eventually going to win out just doing this as randomly as i can maybe in this corner i see four that are pretty closely synced yes now it's more like five six now you have one that's almost completely out of phase so every time the majority hits a beat it's going to give a little impulse a little push to the platform and that push is transferred to the metronome that's not in sync because the platform you can actually see this platform vibrating back and forth in sync with the majority of these metronomes working on this one pretty close to resonance right now as the metronomes achieve resonance it's important to notice how the platform shakes now it doesn't have to just be the force that's being transmitted by the plastic platform it could be a force at a great distance for example the force of gravity just these small little seemingly insignificant pushes building up over multiple cycles can have dramatic energy transfer that is how planets do it like the metronomes the two gas giants form a resonance we don't know exactly how long that took but we have some fiducial marks for timing in the solar system formation and that means that the grand attack had to have occurred relatively quickly talking hundreds of thousands of years perhaps to a million years the two planets retreat until they reach their current positions the sequence of planets as we find them today is based on jupiter and saturn's orbits the planets eventually achieve a sequencing that many students learn through a mnemonic such as my very educated mother just served us nine pizzas was there a time when the mnemonic was scrambled seems very likely the answer is yes not to mention a lot of additional letters were probably in there as well jupiter's menace of the inner solar system is finally over if saturn had not formed at the right time in the sufficient size jupiter would have continued migrating in throwing out objects unfortunate objects in the inner solar system and ending up very close to the sun where it would stay yes the earth would be gone or if the earth would have had a terrifying encounter with jupiter and would have been at its orbit changed dramatically to gosh knows what there is mounting evidence that earth had a terrifying visitor not jupiter they was this planetary body that was roughly the size of mars and through this uh collision a lot of particles were ejected probably completely destroyed we don't really know how much of sea was preserved earth is rocked off its axis its surface liquefied chunks of earth's mantle are shoved into space as a planetary body thea ceases to exist its remains are absorbed by the earth and intermingled with the debris field a new planetary body is formed the moon further evidence is found in rock samples from the apollo moon landings this is a sample from the moon if you can see it this is this was collected by the apollo 15 mission moon rocks contain isotopes identical to those found on earth when the moon arose it is first covered with a magma ocean people imagine the lunar magma ocean to be like this magmatic chamber i am describing but at the surface and covering a whole planet i see it as this ocean like the pacific but this has to be like completely magnetic orange and like probably like fluxing around and probably moving conditions in the lunar magma are as hellish as we can imagine but a microscopic treasure forms in the magma crystal zircons these are the same gemstones used in jewelry but the zircons and the apollo moon rocks yield a different treasure so those zircon are very important because we know they crystallize in this lunar magma ocean we know roughly when they crystallize in the luna magma ocean so they are one of this old piece of the moon that we are looking for one of these old piece that we can use to to date the origin of the moon zircons not only give the age of the moon they set a specific date for the collision the age of the moon is 4.51 billion years old 4.51 billion years ago thea becomes part of earth and forms the moon but the story is not over space probes measure the moon slipping 3.8 centimeters further away each year one day the moon will break free when that day comes there will be no more tides no more romantic moonlit nights could planetary orbits be inherently unstable could the chaos of planetary migration return oat provence observatory france it's here that a discovery from a far away star gives one of the biggest revelations about our own solar system the story begins when swiss astronomers didier cuello and michelle mayor noticed something unusual about a star 50 light years away in the constellation of pegasus everything about this star is ordinary a main sequence mid-life yellow dwarf just like our sun but with one strange difference the star at pegasus 51 is rocking back and forth it's a weird anomaly astronomers have never seen before they check their instruments everything is working including their new spectrograph a device that splits the starlight from pegasus into rainbow colors hidden inside the colors are patterns of lines by tracking the day-to-day movement of these lines astronomers make a startling discovery pegasus 51 has a planet but no one has ever seen a world like this it's half the mass of jupiter yet it's extremely close to its star nine times closer than mercury is to the sun the planet at 51 pegasus must be inside the corona broiling in temperatures over a million degrees fahrenheit soon another planet is found around another star and then another and another astronomers have now confirmed over 3 700 exoplanets beyond our solar system nearly all of them are jupiter-class planets grazing their hosts star they're a new previously unknown type called hot jupiters they're so numerous hot jupiters challenge theories about the origins of planetary systems [Music] it's very difficult to make a planet close to the star because there isn't enough mass to build a giant planet very close to the star and there's gravitational frustrations for trying to build a planet very close to the start astronomy is shaken with a new revelation planets do not stay put where they're born when they're big enough they migrate it's a process called planetary migration and yet our own solar system has no hot jupiter astronomers realize the jupiter in our solar system was once on the move as well but its migration was halted by a resonance with saturn pegasus 51 shows where a planet lands when its migration is not blocked the strongest evidence for the grand tech hypothesis comes not from our solar system but from exo worlds charted around other stars planetary migration is a universal concept we see it evidence of it out there in extra solar planets other solar systems there's no reason why planet migration shouldn't have operated in our own solar system the new horizons probe finds evidence for roving planets within our solar system while charting ancient craters on pluto and on the surfaces of its moons the science team discovered many craters are the same age this suggests that they were formed by a single event even way out here tiny pluto was smashed by a wandering planet the pluto catastrophe may be related to other planetary migrations in the outer solar system [Music] it was noticed that the exact orbits of the giant planets particularly the outer giant planets the icy planets uranus and neptune can be explained by their migration outward there's a point in time about 3.8 billion years ago where uranus and neptune trade and it's because of what some of these mean motion resonance interactions that we were talking about earlier so this mean motion resonance involving jupiter and saturn and so forth just causes all heck to break out in the solar system uranus and neptune all of a sudden the 3.8 billion years they literally swap places and all that debris in the outer solar system gets flung inward towards the inner solar system the disruption in the outer solar system causes a new wave of violence astronomers call this epic the late heavy bombardment much of the cratering we see on our moon today is from this period it may be possible that swapping orbits with uranus is how neptune got its moon today the epoch of planetary migration appears to be over the solar system seems stable but what does the future hold computer simulations reveal what may be the greatest threat to the solar system in over 4 billion years it comes from a very special relationship between jupiter and mercury [Music] mercury's orbit is slowly perturbed thanks to a subtle but constant gravitational nudge from jupiter a new resonance like the one between saturn and jupiter that's saved to the inner solar system is forming between jupiter and mercury in 2001 computer models for the solar system were run 2 500 times they plug in the positions and the orbits of all the planets in the solar system in a computer and they just let it run through time through millions of years hundreds of millions of years billions of years to find out whether or not these orbits are stable change the location of one planet say mercury by one millimeter and you find that that change will give completely different predictions about where everything is going to be millions of years in the future [Music] to see how quickly and easily things can change we have only to go back to our metronomes all i have to do is stop this platform from moving so that it cannot swing freely now there's no way for the metronomes to influence each other they're good metronomes but they're not perfect they can't be going at exactly the same frequency in the same phase and they're just going to fall apart because they have no way of forcing the others to go to resonance the same applies to planets any small change can disrupt their harmony or restore it now that the platform is free to swing again it can again transfer energy and sync them up just like we saw the first time scientists want to understand the consequences of a destabilized planet mercury in one case mercury leaves the solar system the loss of its gravitational pull disrupts the balance of both venus and the earth earth and venus swap orbits the superheated atmosphere of venus cools massive rains pour onto the face of the desert planet oceans arise the land cools and the air thins even the remains of an ancient visitor begin to cool off venus becomes like earth but the reverse happens to the earth as earth settles into venus's orbit temperatures rise the air becomes unbreathable glaciers melt oceans boil the sun looms larger in the sky only to be obscured by a thickening cloud cover suffering will be great but brief the entire 4 billion year pageant of life is cooked in a matter of days complete and utter destruction and elimination of all life on earth not just looking at that higher life i'm not just talking about civilization but everything a sterilization of the planet is something that i would want to think about a bit sterilized uninhabitable and quiet there is another possibility equally dark and apocalyptic a runaway mercury is deflected by the gravity of venus and barrels toward the earth it may be a frightening encore to the opening act of our solar system just as thea did 4 billion years ago the question is could it happen today or is it a fate far away in the future at a time when mankind itself is but a distant memory the problem is that even with a perfect computer that understands all of the laws of motion perfectly not just gravity but all the other subtle forces that go into it you cannot give it accurate enough initial information about the locations the masses the sizes the speeds of all of the objects in the solar system odds are we may never see such a calamity and yet among the billions of stars in our galaxy how many worlds are on the move how many will share this fate [Music] the sun brilliant powerful giver of life but this is the story of how the sun will one day become our enemy if we are to survive we'll have to leave the earth we'll need to seek out new homes and amazing new places and change other worlds to recreate the earth we left behind in the far future our sun will become a monster it will burn all life from our planet destroy entire worlds and finally our sun will even destroy itself it's going to happen one day our sun will die and when it does we'll go with it it's time to think about the future [Music] [Music] for five billion years the sun has nourished the earth it is the sun that provides the energy for plants to grow it is the sun that makes life on earth possible but that will change [Music] slowly unstoppably our sun is getting hotter and hotter [Music] once it gave life to us all but what it gave it can also take away if human beings are to have a long-term future we must leave our planet behind and search for new places to live one day our homes will be out there somewhere in space [Music] in the distant future this could be our home out here in space we'll have to seek refuge on new worlds where we could settle and live [Music] and the reason is we have to escape from our sun [Music] some new worlds may be difficult to adapt to others may be very like our own but what is it that makes our planet so special and why is it so dependent on the sun [Music] here is the sun as it is today in the center of our solar system the earth goes around it about there there are the other planets [Music] the reason why our planet is the one that's life on it is that it is just the right distance from the sun closer in and we boil further out and we'd freeze [Music] we live in a kind of safe zone that's perfect for life the trouble is that zone is moving the sun is getting hotter and as it does the region where life can exist shifts further and further out ultimately the safe zone will leave earth behind when it does we'll be in serious trouble our planet will die [Music] this is how it will happen as the sun burns up its nuclear energy it will become hotter and hotter by the time it's five percent hotter plant life everywhere will be dying [Music] ten percent hotter and animals too will begin to die 15 hotter rivers and oceans will evaporate creating huge cloud banks trapping more and more heat in the far future life on earth will become impossible and there's nothing we can do about it what will happen to us then astronautical engineer robert zubrin believes he has the answer he wants to find us a new place to live the only real choice that we have is to uh grow expand become a space faring civilization or to become extinct not only would we become extinct but unless we become space faring civilization and bring earth life out with us into the universe all life on earth will become extinct robert zubrin's goal is to make us a home on mars today mars is cold and lifeless temperatures regularly drop to 100 below freezing and its atmosphere is 200 times thinner than our own a person standing unprotected on the surface of mars would be dead in seconds [Music] yet some scientists believe we could still learn to call this home mars is the only other planet in our solar system that has on it all the resources needed to support life it has water it's frozen to the surface it's ice and permafrost but it's there it's got carbon dioxide in the atmosphere it's got nitrogen in the atmosphere and if humans go to mars and develop the craft of how to use these resources then we can make mars a place where human beings can sustain themselves we can make a new world for our posterity [Music] no species can expect to last long if it stays in the same place in a very real sense humans are not native to the earth we're not native to north america we're not even native to europe we're native to kenya that's why we're tropical animals with long thin arms no fur but humans were able to live there and colonize the earth by becoming creative man the inventor that's how we coped with ice age europe and that's how we're going to cope with mars and the planets beyond [Music] in a remote part of canada researchers have already been preparing for life as pioneers on mars [Music] living in a space park did prove difficult but they coped supreme is optimistic we're ready to take this on and frankly if we shrink from this challenge what it would really mean is that we have become much less than the kind of people we want once were ignition sequence we are much better prepared today to send humans to mars than we were to send people to the moon in 1961 when john f kennedy started the apollo program i believe that this nation should commit itself to achieving the goal of landing a man on the moon and returning him safely to the earth we were there eight years later there is nothing in this that is beyond our technology it's just a question of showing a little bit of moxie for zubrin it's not the technology that's lacking it's the will but technology and willpower alone may not be enough just look at what we'd leave behind [Music] this is our life support system the plants that create oxygen countless species of animal how will we fare without them [Music] our survival depends on the living things we share our planet with the air we breathe the food we eat all this is created by other forms of life if mars is to be our home it'll have to be home to all of this as well [Music] fifteen years ago we thought we knew the answer this is biosphere 2 a huge glass dome covering three acres of arizona desert completely sealed off from the rest of the planet the theory was that people could survive in it because the whole environment was self-sustaining trees would provide oxygen artificial clouds and oceans would regulate the climate but the experiment failed food rapidly ran short the extra air had to be pumped in on mars that failure would have killed them all if we're ever going to call the red planet our home clearly something's going to have to change and easiest thing to change may be mars itself it's an idea called terraforming the aim is to transform a whole planet from a place where we couldn't survive to one way we could [Music] nasa scientist chris mckay believes we could turn mars into something surprisingly like earth when we think about going into space we tend to focus on humans but in fact it turns out that it's easier for plants and microorganisms to go to mars first they're going to be the first martians in death valley in california chris mckay is seeking earth's most hardy creatures creatures that might be able to survive on mars that's our guys these green smears are algae microscopic organisms that can thrive even in the harsh and variable climate of death valley you can see that and they could thrive on mars too sucking in its thin and unbreathable atmosphere of carbon dioxide and pumping out oxygen in its place except at the moment even the algae would find mars deadly the first step to make marsh habitable habitable even for the toughest little algae is to warm it up a bit right now it's too cold and too dry for any type of life from earth well warming up a planet is something we know how to do we're doing it on earth the pollution on earth would be the medicine on mars it's a strange twist the best way to make mars a place we could live may be to pollute it his heart would work [Music] first a spacecraft has to drop off the pollution creating machines [Music] machine's job is to suck up a mixture of martian dust and atmosphere and process it into new chemicals it then belches out these greenhouse gases to warm the planet and dark soot to soak up heat from the sun [Music] if we send enough machines over time mars will warm up enough to allow these algae to survive [Music] and the algae will begin to give mars an atmosphere of oxygen [Music] but to speed the process up we would need more efficient oxygen makers and the best that we know are plants and trees [Music] the real goal to making mars breathable is to get trees growing there those trees those will be the ones that make the habitable world and then things will really start happening as the oxygen level built up insects maybe small animals and eventually large animals and maybe even humans could then survive naturally [Music] we could change mars [Music] if i were to lay out a time scale i would say 50 years humans go to mars and soon thereafter the algae and the bacteria go to mars and maybe 30 years later the trees go to mars and then the humans come back but this time in a natural setting that's biologically suitable for them and then we've learned how to become a life form that lives on two planets not just humans but all of life [Music] it's a bold and astonishing plan if it works we could turn mars into a planet very much like earth [Music] but even mars will not last forever even there we could never escape the power of the sun [Music] as the sun keeps getting hotter safe zone for life moves further and further out [Music] this is mars earth's dead this is our home thanks to our terraforming it looks a lot like earth and thanks to the hottest sun it's now in the safe zone the only trouble is the sun is still getting hotter eventually the safe zone will leave mars behind as well and with mars daredevils david brin is a science fiction writer he imagines future worlds for a living well it's a big universe out there and the earth is a very specialized environment but we're not going to find many earths out there if we want to spread out into the galaxy then we're going to have to adapt to the universe uh it's not very easy for human beings to get accustomed to that idea because we're used to making the environment adapt to us [Music] as the sun becomes hotter new worlds will warm into life [Music] this is europa one of jupiter's huge moons we know today as a frozen planet airless with a crust of iron hard ice but in the future it will be something else entirely the ice will have melted europa will have become an ocean world after mars perhaps we'll come here and make this our new home [Music] we could live in cities at the bottom of an alien sea but david brin thinks that in the end a life behind glass may not be the solution [Music] now we're thinking of going to other planets at first we'll arrive in spacesuits live in domes bringing our earthly environment with us but eventually people will want to get out of those domes and part of that will involve changing ourselves to fit into new environments our ancestors evolved for life on earth but bring things our descendants may redesign themselves for a future on other worlds human beings have been wonderfully inventive in the last 20 million years and yet other species have not been idle birds develop lungs which the air flows through from one side to the other so all of the lungs are used we only use about half of our lung capacity if we were to just genetically engineer ourselves so that our lungs flowed through like those of birds think of the thin atmospheres that we could live in wouldn't it be great to be able to hibernate like a bear we'd be able to travel to far planets possibly even for our stars [Music] and if they live and work in zero gravity eventually they're going to get sick and tired of pulling around a third of their weight in these useless legs which are only good occasionally for pushing it against walls why have legs if you're in zero gravity when you could have two additional arms wouldn't it be more functional jumping all over the place like gibbons [Music] can genetic engineering achieve any of these things who knows we're just at the beginning of this grand adventure but it's an extravagant version of tomorrow that we should be thinking about wouldn't it be a desirable thing if they're happy if they're creative if they're productive if they're part of a great civilization viva la difference we can only guess of the future what will our descendants be like we'll have to wait and see and where will they live because the only certainty is it cannot possibly be here it's not just that the sun will have seared all life from planet earth is that the planet itself would no longer exist everything we know will have disappeared because in the far future our sun will turn into a monster it's going to consume the solar system its first victim is the closest planet mercury next venus is transformed into a molten fireball and ultimately boiled away [Music] and still the sun grows it's 160 times its original size 2 000 times hotter [Music] and its next victim is the earth [Music] long since seared barren by the sun the place we once called home now melts and is engulfed [Music] seven billion years from now the earth will be gone [Music] for us today one question remains is the future of our planet also our future can we really survive the death of planet earth look at where we stand today look at how far we've come compared to the world of 100 years ago we're living in a science fiction universe with skyscrapers 100 stories tall who can believe looking at that that looking forward to the next hundred years there will not be a new branch of human civilization on mars and look back a thousand years now the world lit only by fire who can say that a thousand years from now there will not be hundreds of new branches of human civilization filling out worlds on orbiting hundreds of stars in this neck of the galaxy some people think that we're living at the end of history but i couldn't disagree more i think we're living at the beginning of time we're present at the creation it's a glorious time to live [Music] for all we know we might be the only life form in the galaxy in the universe if that's true i think that really deepens the importance of the role of humans in spreading life beyond the earth [Applause] if we're the only spark of life then we certainly don't want that spark to go out our scientists today are already imagining strange and far-off tomorrows for our kind and if we do survive perhaps we will be there to witness the moment when our son's transformations finally end it was first the giver of life then the destroyer of worlds and now it too is doomed this is the sun at the end of its life layer after layer it is blowing itself apart huge clouds of star stuff drift out into space it's a slow process it takes millions of years and what follows is inevitable the death of our son it casts off one final layer and its spark is extinguished forever [Music] so the sun will one day go out will that be a significant event to our descendants billions of years hence i don't think so they will have observed similar phenomenon on innumerable other stars long before that time but if they did think about it they would note with gratitude that their ancestors did not stay on that one little world and await their doom but rather spread forth into the universe and made their life possible [Music] no one can know our future but our son's future is certain there will come a time when we must leave our earth behind our planet will be gone [Music] we humans have come a long way traveling our world in search of new lands spreading to every corner of the globe but the time has come to look to new destinations to go once more into the unknown this is the story of our journey in space [Music] we will fly to the stars on a ship that sails on sunlight [Music] we'll explore the most distant edges of the cosmos by taking a roller coaster ride through the very fabric of our universe [Music] and we'll discover the machine that has charted the heavens as never before it's the voyage of a lifetime a voyage to our future in space [Music] [Music] [Music] [Music] we've always had the urge to explore our ancestors journeyed into the unknown to discover new lands and now it's time to do it again but this time it's not a voyage between continents this time it's a voyage to the stars [Music] as our telescopes get ever more powerful they have shown us a universe of unimaginable beauty and power [Music] vast clouds where new stars are born strange galaxies even tantalizing hints of new worlds [Applause] but they've also shown dangers disasters so huge they could destroy the earth in seconds [Music] space is full of terrors and wonders but will we ever see them for ourselves it's less than 50 years since we took our first steps out into space since then thousands of rockets carrying hundreds of people have made the 10-minute flight into orbit astronaut's story musgrave is one of a new breed of space adventurers when you see a large from the outside it's a rather glorious magnificent thing inside is the absolute opposite of that it's 137 decibels it's shaking everything is shaking you have a solid rocket boosters that are really pounding the vehicle and all and then you have the turbulence in the atmosphere that adds another shake rattling roll and so you're basically in a small closet here with belts and straps and helmets and gloves and parachutes survival gear and you got all of this that is all over you and at the same time you're being shook and i can't help but pass through your mind you just want the whole stack to hold together you're along for the ride and you want to survive that [Music] so it's not a joy ride for me it's what i need to go through to get into the incredible serenity and the celestial dance of zero gravity [Music] hello houston we are inspired we are ready we are becoming a race of space fares it's a strange and unfamiliar world but for the privileged few who go there it is an experience they can never forget space walking is much more like a dance than anything else you choreograph every move you choreograph every finger every toe everybody position and how you're gonna do all of that it's just as precise as a ballet going into space it's opening night at the ballet doing a spacewalk i love to look at my feet you see your boots going 18 000 miles an hour 25 000 feet per second you see your boots going down the road [Music] if you ever want to play superman that's where to do it we stand on the edge of space our most ambitious project is testament to what we have achieved the international space station freedom [Music] but it's surprisingly close to home it's floating less than 400 kilometers above our heads [Music] the furthest we've traveled into space is this in 1969 we set foot on the moon that's one small step for man [Applause] [Music] for the first time ever we looked back at our home from the surface of another world [Music] it's amazing to think that people have actually walked up there voyager left earth in 1976 it passed jupiter then saturn and now it has left all the planets far behind after decades in space it's 14 billion kilometers from earth [Music] it's an impressive journey until you consider this on this scale the nearest star to our solar system is way over there in fact it's over 100 kilometers away to reach it would take voyager another 25 000 years and voyager speed even reaching the nearest star is an impossible journey but perhaps there's hope it's easy to forget that in a single person's lifetime we've gone from this to this [Music] and in our quest to reach the stars some scientists believe the answer could be to go from this to this deep space one its secret is a new kind of engine the iron drive and it's the passion of nasa scientist mark raymond the idea for iron propulsion's been around since long before i was born but the first time i ever heard of it was in a star trek episode they're using ion propulsion and spock says configuration unidentified ion propulsion high velocity unique technology and i thought well this is really amazing but i'm never going to see anything like that in my lifetime but in 1998 mark raymond's dream became reality [Music] deep space one but what is it that makes the iron drive so different [Music] compare it with the conventional rocket [Music] the rocket fuel burns with tremendous force and as it thrusts down it pushes the rocket up [Music] in the laboratory mark raymond watches a prototype iron drive in action instead of tons of rocket fuel the engine uses a few grams of a gas it gives the gas an electric charge and spits it out atom by atom at incredible speeds creating a seemingly gentle blue haze [Music] the iron drive doesn't have the raw power of a rocket it has something better staying power it's a bit like the hair and the tortoise [Music] [Music] [Music] conventional rocket engines create huge thrust and awesome acceleration but they burn through their entire fuel supply in just a few minutes after that it's all over [Music] the iron drive is nowhere near as powerful in fact it would take deep space one four days to get from naught to sixty but the reason deep space one is the fastest spacecraft ever is because it's been accelerating for almost two years when we communicate with that spacecraft out so far in the solar system to think that our baby is out there this little spacecraft that we built i just i think it's really amazing iron drive spacecraft will be fast enough to chase down comets or travel around the planets of our solar system in just a few months but even iron drives don't last forever eventually they too will run out of fuel to travel further to reach the stars we'll need something new and it may be based on one of the oldest technologies we know the sale long ago the limitless power of the wind carried our ancestors to new worlds in the future we may use the same idea to travel to the stars on sales that catch nothing more than sunlight a solar sail using only the light from our sun [Music] many scientists are sure that this is the future of space travel [Music] one of them is les johnson the sun puts out photons light standing here on a sailboat the photons that are falling on us are pushing on us but the push is so slight that we don't feel it all the other forces around us are so much higher in magnitude that it's not noticeable but in the vacuum of space if you have a large enough light enough material the the pressure that's exerted from the solar photons can cause that to move to see if sunlight could provide enough force to drive a sail through space johnson and his team built this a man-made sun in front of me we have a simulated sun about three times brighter than what the sun is at the earth and that's the reason i'm wearing these uv protecting sunglasses and that it could damage your eyes if i were to accidentally look right into the beam [Music] they're testing the ultra thin ultra lightweight material they would need to make a real solar sail it's mounted on a rod in the full glare of their artificial sun as you look in there you can see it slowly rocking back and forth what's causing that is the sunlight pressure of the photon pressure as is pushing on the sail incredibly it works this piece of sail material is being moved by nothing more than light [Music] based on work that's being performed around the country solar sail technology is getting to the point where very soon we'll be flying it in space to reach the immense speeds needed to travel from start to star the solar sail must start its voyage with as bigger push as possible [Music] it must fly as close as it can to the source of its power the sun it's a dangerous maneuver but if it works the craft will whip around the sun and hurtle out into space [Music] at almost three quarters of a million kilometers an hour [Music] a solar sail could reach the nearest stars in just decades it's a truly impressive start but is it enough [Music] [Music] our galaxy is a very big place to get from one side to the other even using a super fast solar cell traveling at incredible speeds would still take two and a half million years and our galaxy is only one of billions that make up our universe [Music] and this is the final frontier if we ever want to be true star travelers don't have to take a completely different approach we're going to have to learn how to manipulate the very fabric of space itself some scientists believe there may be a quicker way to get around the universe one of them is cosmologist peter coles [Music] when early man first began to explore his environment he would run into fundamental barriers whenever he came across mountains the mountains are not easy to cross when you're faced with a wall like these mountains around us you've got no choice either but to go around them or over the top [Music] now these days it's exactly the same thing with space travel if we're going to explore and colonize our galaxy and the distances we have to travel are truly immense so when it comes to space travel we're really still very much in the stone age [Music] the answer could be to take a shortcut don't go round the obstacle go through it [Music] if you travel through space you're fundamentally limited by the speed of light but it's just possible that the laws of physics might have a kind of loophole in them which allows us to travel slower than the speed of light but still travel huge distances in a very short time and the way you can accomplish that is through a wormhole the wormhole is basically a tunnel that takes a shortcut through space-time say here to the nearest star could be connected by a very short tunnel wormholes may sound like science fiction but creating one may just be possible first we'd have to harness the incredible forces of an exploding star and use them to punch a hole through space we'd need exotic forms of energy to keep the tunnel open but the science is sound at least in theory it is possible to create a tunnel that reaches clear across the universe [Music] experiments have already begun to try and build the first tiny wormholes [Music] in theory wormholes would take it from one side of the universe to the other literally no time at all instant travel [Music] anywhere the wormhole could just as easily have taken me halfway across our galaxy but with the universe at your feet how do you decide where to go for that you're going to need a map [Music] space as we've discovered is very big but professor brian boyle and a team of australian astronomers may have the beginnings of an answer [Music] they're creating the biggest map imaginable a map of our universe traditionally astronomers have looked at the universe as a flat map on the plane of the night sky [Music] you can think of it like a map of the earth for a hiker a flat map it's no use at all a flat map wouldn't tell you if there was a mountain in the way or a huge ravine [Music] in the same way the hikers of the future will need a three-dimensional map to guide them around to create a three-dimensional map boyle and his team had to develop a unique piece of equipment ten years in the making and weighing over three times the device uses over 600 fiber optic cameras [Music] the whole apparatus is delicately maneuvered into position high up on one of the biggest telescopes in the world everything's connected up we're ready to go fiber's in position what we're going to do now is to take the telescope back up to the top and wait for the stars to come out [Music] every night the telescope looks at a new patch of the night sky [Music] and for each point of light it sees a robot places a single fiber optic camera the light from the object is measured and its distance from the earth accurately calculated [Music] so far the tireless robot has looked at and logged the positions of tens of thousands of stars and galaxies [Music] bit by bit it has pieced together an unequal picture of the universe [Music] and this is the result for the first time ever we can see what our universe looks like in three dimensions [Music] [Music] when the map was first created i was really filled with a sense of mixture of awe and excitement here i could see almost developing in front of my own eyes was the structure of the universe giant archipelagos of galaxies stretching hundreds of millions of light years across intergalactic space [Music] the day before i'm going to launch them right here i go to the beach right over there i go to the ocean if i lie in the ocean and i look at the satellites crossing overhead but i look at those satellites just whizzing along and i think tomorrow that's me [Music] so i think on that kind of thing where you don't know if you're coming back and you don't know the final outcome and you may not really know where you're going to end up you focus on a journey and that's what carries you forward [Music] there's a lot out there to explore and one day humanity may be lucky enough to do it our children or our children's children will reach for the stars so the next time you look at the night sky remember that space is stranger and more beautiful than we can begin to imagine and above all remember this out there in space is our future [Music] [Music] [Music] humanity ignorant in bliss we go about our lives unaware that in the depths of space lurk invisible monsters [Music] destroyers powerful enough to tear apart our sun and leave our earth a shattered burned-out ruin you are about to enter the world of the universe's ultimate killer we will be there when the monster is created in the heart of a dying star we will search for its telltale signs in the darkness of deep space this is the story of the power that may one day destroy us all the black hole [Music] [Applause] [Music] [Music] the note saying what goes up must come down the thing is it's not always true if you throw something hard enough it might never come down [Music] if something goes up fast enough it can escape the earth altogether faster still and it can escape the immense pull of our sun the force that holds the planets in place [Music] in fact travel fast enough and you can even escape the pull of the billions of stars that make up our galaxy the milky way [Music] but there is one object out there whose pull is so powerful you can never escape no matter how fast you go not even if you travel at the speed of light meet the monster this is a black hole in action it is tearing apart a star that is straight too close anything that comes near is destroyed [Music] it's hard to believe anything could be powerful enough to destroy something as big as a planet or a star but it's true let's take a closer look put a black hole near something and immediately it starts ripping it apart there's a star in there could just as easily be our sun and it's being pulled apart by a black hole on this scale our earth would be no bigger than a pebble we wouldn't stand a chance shocking thing is how small the black hole is black hole itself is right at the center of the disc it's tiny it's a million times smaller than the star just look what it can do [Music] what is it about a black hole that makes it so powerful the answer is gravity it's the force that keeps us all stuck to the surface of our planet if something's heavy enough it pulls you towards it and planet earth is heavy so heavy in fact that to get off it you have to do this all of this just to escape from our tiny globe [Music] and if earth's gravity seems strong imagine the pull of the sun our sun is a million kilometers across this is the real heavyweight of the solar system but if you think our sun is big think again there are stars out there that are vast their gravity is mind-boggling [Music] but compared to a black hole even this star is a weakling a black hole weighs as much as a massive star but it's crammed into an area smaller than a pea black hole is gravity gone mad nothing can ever escape [Music] what could create such a monster something so heavy and yet unimaginably small [Music] an event powerful enough to create a black hole should be clearly visible right across the universe and recently we might actually have witnessed one as it happened it was a team in australia headed by professor brian boyle that spotted it the first clue that led to his discovery came in the form of radiation gamma rays that are invisible to the human eye night sky that we can see with our own eyes is only part of the picture light comes to us in many different forms from low energy radio waves to the most highest energy form of light the gamma rays the form of light that packs the biggest punch every night in the gamma-ray sky is fireworks night we've been detecting violent bursts of gamma rays for decades but we've never actually seen what causes them it has to be a violent event but what kind problem is gamma ray bursts only last a few seconds to make things harder the best way to detect them is from space gamma ray observatory to during a routine observation the gamma-ray observatory detected an enormous blast of energy going off in deep space what had triggered it brian boyle's team guided by the space observatory turned their ground-based optical telescopes onto the blast in the hope of seeing it before it had time to fade [Music] the information was relayed down to the ground and the optical telescope sprang into action to try to localize where this burst of energy had come from [Music] what we found was something we didn't expect that this light was actually coming from a supernova [Music] what they'd seen with their telescopes was an exploding star but the explosion was far larger than anyone had ever witnessed before and in the heart of that cataclysmic explosion the researchers realized that something astonishing and terrifying had happened as the massive star died a monster had been born what we witnessed was the birth of a black hole what boyle's team had seen was the death of a star so heavy that when it exploded its entire mass collapsed inwards instead of blasting outwards into space this star is absolutely huge it's a hundred times bigger than our sun thousands of times brighter [Music] but it doesn't just explode as its surface layers blast outwards its core is smashed inwards [Music] the center of the star collapses in on itself billions upon billions of tons of star stuff crushed smaller and smaller until the whole star is squeezed to a single and from the remains of the dying star a black hole is born [Music] in our galaxy a massive star explodes and creates a new black hole every thousand years which may not sound like a lot until you remember that the galaxy has been here a very long time speeding up its history you can see that stars will be going off like firecrackers and when a black hole is born it never dies every black hole that was ever created is still out there so there should be around 10 million of them somewhere the question is where [Music] [Music] until recently black holes remained unseen in the depths of space but something as deadly as a black hole can't remain hidden forever like most predators they leave a trail of destruction [Music] and scientists are now beginning to recognize these telltale signs one black hole hunter is john 11. even though black holes are dark and invisible it doesn't mean they have no effects or extremely strong vortices and they pull matter in these swirling winds around them a lot like a tornado [Music] and just like a tornado you might not see it until the debris begins to get sucked up like this tornado is now pulling the gases in and so suddenly you can see the the presence of this vortex the strong swirling wind [Music] it isn't the wind of a tornado you see it's the havoc it creates [Music] that's how we detect black holes too by the damage they do even though tornadoes are incredibly powerful you don't see them until they suck stuff into them until you see them pulling up cattle and houses and cars and and gas and smoke and clouds and it's the same thing with black holes so you don't see them until they pull in the matter around them [Music] this is what astronomers look for not the black hole itself but stars caught in the black hole's incredible gravitational pull this one is tearing apart a star that drifted too close a feeding black hole is anything but black [Music] the whole star is wrenched out of shape as the monster tugs of it [Music] gas from the star whirls around the hall it forms a super hot disc of start every 100 000 kilometers across [Music] it's a deadly embrace that will last millions of years and what the black hole can't swallow it belches out huge jets of uneaten star are spat out into space [Music] some of the most spectacular kinds of black holes we've seen are so powerful they're drawing in so much material and spinning so rapidly that create these huge jets these powerful funnels of material [Music] that are thin but incredibly incredibly long incredibly vast and the jets themselves can cross as much as an entire galaxy they're absolutely huge the damage a black hole inflicts on a star can be seen clear across the universe once astronomers knew what to look for they began to hunt for feeding black holes using powerful space telescopes we've tracked down more and more of them and these are the actual images black holes tearing apart everything they meet [Music] most of them are remote they're in distant corners of the universe and we've only found them because they're feeding but what about the black holes that aren't feeding where are the millions of black holes that should be wandering through our galaxy they remain hidden against the dark background of space luckily there is a way of tracking even the blackest of black holes and this is what gives them away light a black hole's gravity is enormously powerful it affects everything around it can even bend light so when a black hole passes in front of a distant star the light from that star is distorted and the black hole gives itself away finding a start the precise moment it's distorted by a black hole is a daunting task but that didn't stop one very very patient astronomer trying to see the invisible tim axelrod has dedicated many years of his life to the pursuit of the universe's hidden objects [Applause] for the last eight years we've been looking at the same patch of sky every night monitoring the brightness of 20 million stars [Music] the reason that we're doing this is we're looking for microlensing events these events are extremely rare but they occur when a massive object passes across our line of sight to a distant star axelrod set about his search for what he calls gravitational microlensing when a star's light is distorted by a massive object like a black hole [Music] but the odds were stacked against him at best his chance of finding the right star was one in a million that factor just seemed impossibly large to people so most people thought that we would fail pretty dismally [Music] [Applause] undaunted by the enormity of the task and the skepticism of his colleagues axelrod set about looking for that one telltale pinprick of light amongst 20 million stars every night for eight entire years then one night he hit the jackpot here we have a view of the large magellanic cloud the blue square shows the field of view of our telescope so now we've zoomed in a bit the star which we're interested in is a pretty inconspicuous fellow right in the center of the crosshair now we zoom in yet again this is picking the needle out of the haystack and what we saw when we looked at it over a period of time was this we were naturally ecstatic everyone that saw it uh agreed immediately that this was gravitational micro lensing so we were just over the moon far out in space he had seen the impossible a massively heavy object like a black hole sliding silently in front of a distant star [Music] next axelrod turned to our own galaxy what he saw was disturbing evidence not of one or two black holes but hundreds but is that anything for us here on earth to worry about could our own fragile planet ever encounter one of these invisible monsters if we do ever meet a black hole it would tear our world to shreds but one thing is sure our skies seem to be full of them and our galaxy still has one last dark secret and it took the most powerful telescope in the world to unlock it the keck in hawaii one of the astronomers using it is andrea guess the keck telescope is a fabulous telescope to use it's great because it's large this is a case where bigger is better you get to collect a lot of photons so you can see very faint things and it allows you to see very fine detail the telescope's vast mirror allows andrea guess to study the center of our galaxy with more accuracy than ever before and what astronomers have seen there is a black hole a million times more powerful than normal here's an example of one of the images we got just last night we actually see that there are fainter stars towards the center of our field of view and these stars are extremely important the motion of these stars that revealed the presence of the black hole [Music] there is a black hole at the center of our galaxy that is so incredibly powerful it spins whole stars around itself at impossible speeds the fact they're going a thousand kilometers per second tells us there's two million times the mass of the sun of matter there [Music] this is no ordinary black hole this black hole is a giant two million times as heavy as our sun and it's not in some far-flung region of the universe this black hole is sitting right at the center of our galaxy [Music] suddenly the idea that the earth might one day fall victim to a black hole doesn't seem quite so unlikely if we are ever unlucky enough to meet one what would it be like it begins far out in space beyond the furthest planets unseen a rogue black hole plows into the cloud of comets that surrounds our solar system and flings them towards earth with incredible force these impacts are the first warning of our fate [Music] as the black hole comes closer its next victim is jupiter the giant of our solar system even from so far away the black hole's gravity makes itself felt here on earth our world is being shaken apart but the black hole hasn't finished yet it's heading straight for the heart of the solar system our sun though tiny in comparison it tears the sun apart dragging the sun with it the black hole heads towards earth [Music] the earth is now unbearably close to the sun [Music] all life has long since ceased to exist [Music] and our planet starts to melt [Music] quietly our battered world disintegrates and is consumed and all that is left is the black hole drifting through space earth eaten by a black hole it sounds bizarre but we know there are millions of these monsters out there what we don't know [Music] take a walk on planet earth it's a wonderful place but don't take it for granted because one day it might just vanish [Music] forever this is the story of the universe we live in and the dangers we face just by being here we'll fly with the comets and asteroids which threaten all life on our planet here on earth we'll recreate our sun's headlong plunge around the galaxy and watch disasters unfold which could spell the end for us all [Music] our planet is under threat our mission is to stay alive [Music] [Applause] [Music] if you're a gambler then this is the planet to live on because just by being here we're all taking a risk and the odds are stacked against us do you feel lucky you should do you may not realize it but we are all winners we human beings are incredibly lucky to be here because the universe keeps trying to wipe us out [Music] trying and failing we have survived every disaster the universe has ever thrown in us so far our run of luck won't last forever when it ends our planet and our entire species will cease to exist unless we can do something about it [Music] could our whole planet really be in danger what could threaten the globe thirteen thousand kilometers across or six billion people to understand the threat you have to see it firsthand i want to show you planet earth as it was in its earliest days this is where it all begins we're lucky there's even a planet here for us to live on because it was very nearly blown apart before life had even begun this is planet earth billions of years ago the very beginning of its life as you can see it is under attack these are asteroids rocks left over from the creation of the planets themselves some of them were vast and one of them was on a collision course with earth this collision nearly smashed our earth to pieces we were hit by a ball of molten rock the size of mars traveling at colossal speed [Music] [Music] the impact ripped huge chunks out of our planet somehow it survived but what about the future smaller chunks of rock are still flying around our solar system today we call them asteroids and they could put an end to human civilization asteroids range in size from pebbles to mountains or even bigger and they're dangerous they're flying around at incredible speeds to get an idea of the damage they can do just take a trip to the moon on earth [Applause] [Music] in 1969 for the first time ever human beings walked on the surface of another world [Applause] and what a world it was airless barren hostile [Music] and bearing the disturbing evidence of a terrifying threat the moon is scarred with craters the marks of countless asteroids that have slammed into it the moon is under attack and traveling through space alongside the moon is another planet the one we call home so why aren't we taking the same pounding [Music] there's a simple answer to that [Music] we are this crater was formed in a few seconds about 49 000 years ago it's almost 1.2 kilometers in diameter it's almost 200 meters deep the object that caused it was an asteroid about 40 meters in diameter came in with a velocity of about 25 kilometers per second and it exploded with a force of a 15 megaton hydrogen bomb this is meteor crater in arizona geologist jeff wynn thinks that what happened here could happen again soon [Music] local effects would have been devastating obviously anything within the circumference of the crater would have been obliterated if you were an animal grazing within a few kilometers you probably would have been killed by the impact blast if you were beyond that depending on where the wind was blowing the ejecta coming down would have killed you and this is just one rather blunt example of what could happen if one of these things did hit geologists are discovering more and more evidence of asteroid impacts here on earth meteor crater would be hard to miss other impacts are more difficult to spot but we have seen them we've photographed them from space these are the remains of titanic collisions some of them vast 20 or 30 kilometers across the earth is being pounded all the time siberia 1908 an entire forest was flattened [Music] there was an impact in saudi arabia in 1933 this was caught on camera in canada in 1972 and the aim is it flew back out into space if it had crashed on earth it would have exploded with more force than an atom bomb [Music] amazingly in all these events no one at all was killed [Music] but even if an asteroid doesn't hit us it could do something even more dangerous it could hit the sea [Music] if a big asteroid smashes into the ocean it could create a huge deadly wave that could wipe out entire cities [Music] i think there's a realistic possibility that something like this could cause serious problems to human civilization sometime in the next century or two it's not an appealing thought but the threat is real whole cities could be obliterated from space whether or not it's your city comes down to luck but before you feel too lucky think about this it may not matter which city you live in there are things out there which could wipe all life from the face of the planet space contains dangers that make asteroids seem utterly insignificant our telescopes have captured images of truly colossal disasters [Music] this photograph shows a star a hundred times bigger than our sun blasting incandescent gas out into space and this is a black hole spewing out jets of super hot matter at close to the speed of light if these have been near us there's almost no chance that we'd have survived [Music] it looks as though fortune has been on our side at least it has so far [Music] but for how much longer [Music] professor mike rampino thinks the odds for long-term survival of life on earth could be slim [Music] luck probably plays a very big role in the existence of life on the planet earth you have to realize that the galaxy is very violent place and if we get unlucky that could put an end to complex life on the planet [Music] here's the problem we don't notice it but planet earth is on the move [Music] while we get on with our lives the world is hurtling around our galaxy at 230 kilometers a second and high speed means high risk some you win some you lose [Music] we may not realize it but we're on the right of our lives think of the earth's orbit this is a kind of cosmic roller coaster ride [Music] as we move in this orbit we're moving past gas clouds we can come close to black holes [Applause] we can get close to stars we can come close to supernova explosions any of these objects could cause catastrophes on the earth sound incredible it's very real life on earth has been all but eradicated on 20 separate occasions and to make matters worse it's going to happen again after all remember what happened to the dinosaurs flying through space is a dangerous business it's not just that we're moving it's where we're going planet earth regularly flies through some of the most dangerous areas of the galaxy well if one could speed up time and watch the orbit of the earth through the galaxy and around the galaxy it would look like a very very fast carousel the sun and the planets moving up and down [Music] and at the same time moving around the galaxy very rapidly we go around the galaxy about once every 250 million years but also we go through the densest part of the galaxy every 30 million years that's the danger zone [Music] every 30 million years our planet earth travels through a region heavily packed with stars [Music] and it so happens that it's every 30 million years or so that life on earth comes close to being wiped out [Music] coincidence [Music] here is our galaxy a huge flat pancake of 400 000 million stars all whirling around the brightest areas are where the stars most tightly packed these are the danger zones and this star is our sun at the moment it's just around there just another pinprick in the cloud of stars that makes up our galaxy but take a closer look and see how it's moving it doesn't just go round and round the galaxy it also goes up and down and where the sun goes the earth goes so regular as clockwork we plunge through the danger zone and every time we do so the odds are stacked against us here's how it works this is our sound and each of those other dots is a star [Music] as our sun bobs up and down through the galaxy we're passing them by the million and where the stars are densest the danger is greatest [Music] the reason those other stars are dangerous is the powerful effect of their gravity on our solar system fly outwards from the sun away from the earth and the other planets and eventually you encounter these chunks of ice trillions of them a vast cloud in space if another star comes too close its gravity disturbs the cloud and catapults ice chunks in towards the sun more than 10 kilometers across traveling at 40 kilometers a second begins its million-year journey into the heart of our solar system we know these huge snowballs by another name this is a comet as it plunges towards the sun it warms up and belches out a haze of gas and dust [Music] an immense cloud trails through space behind it the comet's tail but this comet doesn't hit the sun it skims round it and out [Music] it doesn't bode well for the future the existence of human beings on the earth [Music] we last passed through the danger zone one million years ago but that doesn't mean we're safe yet because a million years is how long it takes for comets to make their way into our solar system [Music] and in july 1994 one smashed straight into jupiter drawn in by its immense gravity these blurred photographs reveal a colossal [Music] explosion he covered an area bigger than our entire planet [Music] if jupiter hadn't intercepted that comet if it hit the earth instead it could have been the end of us [Music] i told you we were lucky and it's not just that jupiter saved us six years ago it has saved us thousands of times it's been doing so since the dawn of our solar system without jupiter life on earth would never even have got started remember all those asteroids in the early solar system back then there were so many of them flying around that life couldn't even get started what changed that was jupiter its powerful gravity sucks in anything that comes too close you're watching at a million years per second jupiter made life on earth possible it drew the asteroids fire and shielded our planet it's still catching asteroids today but unfortunately for us the number of asteroids out there is all but limitless sooner or later our luck will run out just as it did for the dinosaurs jupiter can't catch them all and one is all it takes this one for example the question is what on earth are we going to do about it [Music] it seems we have a problem [Music] this asteroid is huge 50 kilometers across 100 billion tons of rock surrounded by clouds of dust and debris it's traveling at 40 kilometers a second and it's heading straight towards earth [Music] so what are we going to do about it the american military are on alert the man who runs earth's asteroid detection system is sergeant rob medrano [Music] today comments and asteroids do represent the most significant threat that we have from space now they do impact the earth routinely but mostly we're talking objects that are very small what we're concerned about are those objects that actually penetrate the earth's atmosphere in a large form and with that in mind on average we're discovering about four a month the asteroid passes mars it is now only 45 days from the earth already time is running out for us all detecting a threat is not enough the point is to do something about it [Music] there are several possibilities one is to send a rocket up with a nuclear device and blow it to pieces another possibility is to put chemical rockets on the object and literally try to shove it out of the way this all requires that we have enough lead time to be able to mount some kind of a major project like this and do something about it they're really two possibilities for human beings to survive far into the future one is some kind of planetary protection the other is insurance moving off of this planet under other planets so if there are catastrophes on this individual planet it wouldn't wipe out human beings entirely [Music] the potential still exists for an asteroid to impact the earth that would essentially uh wipe out life as we know it in terms of defending ourselves uh today predicting where the asteroid is going to actually impact that that's really all that we have [Music] so far we have survived [Music] but what about the future to safeguard that we should be acting now one day our planet's luck will run out it's simply a matter of time we must develop the technology to defend ourselves because we're not prepared the odds are that one day complicated seriously massive objects warp the fabric of space the heavier the star that is the greater its mass the greater the distortion [Music] so light which would otherwise travel in a straight path gets bent [Music] if a star of any given mass shrinks sufficiently its density increases until its local distortion of space is infinite [Music] that's a black hole a border develops separating the black hole from the space around it once this border has been crossed going into the black hole even light cannot escape [Music] border diameter is determined by the weight of the compressed mass a hole with the same mass as earth would be merely two centimeters across something the mass of the sun six kilometers that's considered the size of the black hole black holes are created the instant stars die [Music] let's say a star 20 or more times larger than our sun reaches the end of its life and explodes [Music] the star's own gravity then causes its remaining core to implode infinitely becoming a purely gravitational force when a black hole is born like this from the death of a star its diameter is 50 kilometers at most but one can find black holes of truly monstrous proportions over 10 billion kilometers in diameter [Music] andrea guez is an expert on this invisible phenomenon of the black hole it was when she saw the apollo moon landing on tv that her interest in space was awakened my biggest uh objective in life when i was very young was to become a ballerina so um i think i see things spinning in space now um as opposed to myself um but yeah your path is uh is uh the path was unclear and today i viewed doing astronomy and studying the black hole is putting together one big puzzle [Music] donald lyndon bell predicted that a supermassive black hole lurks at the heart of every galaxy andrea guezz tried to find such a black hole in our own milky way galaxy actually the first thing that we're trying to do is watch how stars move that's the key to finding that there's a black hole and the way you do this is by pointing your telescope at the center of the galaxy and using a technique that allows you to see the stars around the black hole so here's the black hole and what you want to do is we want to be able to see a star you want to be able to see a star make a complete orbit around the center guests followed the movements of the stars for years plotting their trajectories if they were in fact orbiting some unseen object then that would be proof of a black hole the center of the milky way however is 26 000 light years from earth ascertaining the movements of stars around a point so far off in space is no easy matter [Music] mauna kea hawaii home to several giant telescopes [Music] guess use one of the observatories on this summit the keck observatory the keck has two of the largest telescopes in the world with primary mirrors that are 10 meters in diameter [Music] guess's observations here began in 1995. but guess and her team were not the only ones searching for a supermassive black hole in the center of our galaxy a european team based in the heart of germany had also been hunting the same monster the leader of these star trackers is stefan gillessen they have a 10 meter telescope we have an 8 meter telescope so our telescope is a bit smaller however we are on the southern hemisphere where the galactic center is visible for more hours so we can observe from february to october the european team conducts its observations at the paranal observatory in chile the vlt array there comprises four 8.2 meter telescopes but even with such advanced technology success is elusive [Music] the problem is earth's atmosphere [Music] atmospheric fluctuations blur the stars [Music] april 2002 the european team installs epic making new equipment [Music] from the vlt at paranal they shoot laser beams into the night sky to measure and adjust for those atmospheric fluctuations their special equipment succeeds in doing just that the new method is called adaptive optics [Music] it brings the stars into focus [Music] corrected for atmospheric fluctuations the stars shine much more clearly [Music] guess who did not yet have adaptive optics was at a disadvantage [Music] she minimized atmospheric fluctuations by restricting exposure time in imaging the stars [Music] meticulously she charted their movements success or failure depended on choosing the right stars to follow [Music] at first both teams were following a star designated s01 [Music] but guezza's attention was drawn to another star [Music] another star which people were very excited about in the earliest days was so1 it was the star that was moving fastest initially but it was so2 that as it got closer to the black hole has become the fastest moving star that we've known about this graphic represents guess's findings knowing that stars orbit the center of the galaxy was not enough to prove the existence of a black hole [Music] in january of 2002 another star designated so2 was observed to be behaving strangely [Music] it was executing a blindingly fast and tight orbit clocked at 5 000 kilometers per second as if being swung violently around and around [Music] these were incredibly exciting times because um of course at every stage of this experiment people said you can't do it or what you're seeing isn't um what you should be seeing so we initially saw that they were moving fast and people said well these stars aren't bound to the galaxy you're not going to see them curve yet so2 was indeed curving in a rapid orbit [Music] this is an actual imaging sequence exhaustive analysis showed it to be a giant star with a mass equivalent to 10 suns [Music] the only thing that can make stars move that fast is a lot of mass these stars are moving because there's a lot of gravity and the only thing that makes that much gravity in that smallest space is a supermassive black hole with their adaptive optics the strange behavior of so2 had not escaped the notice of the european team either they succeeded in imaging so2 at around the same time [Music] of course that was the moment everybody was extremely excited about that we saw wow that orbit is proving there must be a mass and we can measure the mass we can actually calculate the mass it's an easy calculation any student can do it and the result is extremely fascinating this mass which we are seeing in these images is 4 million times the mass of the sun [Music] finally after 10 years of observations it was determined that a supermassive black hole does in fact exist in the center of our galaxy [Music] and it is bigger than was imagined by many orders of magnitude black holes created when stars die are typically 50 kilometers in diameter at most but the one at the center of our galaxy is gigantic [Music] the diameter is estimated to be 24 million kilometers that's like 17 of our suns lined up in a row round this monster black hole russia's so2 a giant blue star at 5 000 kilometers per second about 200 times the speed at which the earth orbits the sun that is a speed made possible only by the immense gravitational pull of a black hole [Music] in the center of our own galaxy but far from earth unfolds a dance of the stars [Music] it was this dancing of the stars that proved the existence of a supermassive black hole it was an idea but you know far out and not very much considered this natural and it remained that way for about 15 years lyndon bell had predicted that a supermassive black hole exists at the center of every galaxy apart from observing the orbits of the stars there's another way to prove the existence of such a black hole [Music] that's to observe the moment when a black hole swallows up stars or gases as gases are sucked into a black hole they first flatten into a disc friction causes them to superheat and to emit intense radio waves if these radio waves can be detected that can indicate the presence of a black hole [Music] the largest telescope in the world for detecting extremely high frequency millimeter band radio waves is the 45 meter radio telescope at the national astronomical observatory of japan it was in fact a japanese scientist who first proved lyndon bell's theory that a supermassive black hole lies hidden in every galaxy it happened in 1990 21 years after lyndon bell's prediction now masa nakai was working at the nobeyama radio observatory studying gases at the centers of galaxies [Laughter] he was interested in a galaxy adjacent to the big dipper galaxy m106 a spiral galaxy 21 million light years from earth radio waves had been reported to be issuing regularly from the nucleus of m-106 [Music] [Music] in addition to a 45 meter diameter parabolic dish antenna the nobayama radio observatory has some world-class instrumentation eight spectrometers capable of minute observation of radio waves [Music] a single spectrometer is sufficient to observe radio waves from the nucleus of a galaxy but to be thorough nakai used two spectrometers for the very center of the galaxy and flank them with the six remaining ones [Music] that decision to use all eight instruments led to the discovery of the century [Music] nakai had simply wanted to put all his spectrometers to some use but the results astonished him there were surprising spikes on both ends of the combined graphs nakai was especially struck by the ones on the left this indicated something moving at high velocities never before observed [Music] foreign [Music] more detailed observations were made using a high-resolution telescope they found something remarkable at the core of the galaxy a spinning disc [Music] this was a structure very like the disc formed by gases being sucked into a black hole the spikes recorded by the eight nobuyama spectrometers were from this disc [Music] the disc was spinning furiously 3.6 million kilometers an hour detailed analysis revealed that the mass had its center was equivalent to 39 million of our suns it was indeed a monster black hole [Music] [Music] when his discovery was published in 1995 nakai received a letter the letter read i have been waiting 26 years for such proof and congratulate you on your great discovery the letter came from england [Music] the sender none other than donald lyndon bell who had predicted the existence of supermassive black holes i was very happy because i didn't feel that i absolutely knew i thought it was likely and i gradually i thought it was more and more likely [Music] a black hole equivalent to 39 million solar masses was sucking in huge volumes of gas with its tremendous gravitational force [Music] the dark object in the center of this artist's conception is a black hole its diameter is awesome as if 160 of our suns were lined up in a row it is now thought that almost all galaxies have these supermassive black holes at their center [Music] the most advanced observational instruments are detecting ever larger black holes situated outside earth's atmosphere the hubble space telescope can see space objects with great clarity [Music] hubble took aim at ngc 7052 a galaxy located 37 million light years away the image it captured was that of a huge disc comprised of gases and stars in its center there ought to be a supermassive black hole [Music] when we got this image i was just super excited i mean because it was such beautiful rich detail that i really knew right when i saw this that we were going to be able to get you know excellent spectra and really be able to determine whether this galaxy has a black hole and how massive it is so i was very very excited the galaxy was indeed harboring a supermassive black hole [Music] a black hole equivalent to 300 million solar masses that's more than 70 times larger than the one at the center of our own milky way galaxy a black hole with a diameter of 1200 of our suns lined up in a row [Music] and hubble has spotted an even larger one an ultra massive black hole this one is an m87 59 million light years away scientists had long been puzzled by a band of white light there [Music] when hubble was trained on the galaxy's core the band of white light was revealed to be a gigantic jet of gases [Music] as the gases are sucked violently into the black hole a portion of them are ejected in the form of this jet the mass of the black hole at the base of this jet has been calculated to be 6.4 billion solar masses [Music] that's 10 million times greater than the supermassive black hole at the center of our milky way galaxy in size its diameter is equal to 25 000 of our sons lined up in a row then in 2011 the largest black hole in history was discovered in the galactic nucleus of ngc 4889 there's an unimaginably monstrous black hole with a mass equivalent to 9.7 billion times that of our sun [Music] what scientists are most eager to elucidate now is the process by which these black holes become so large they may start with the death of a star but how do they then grow to billions of times their original size [Music] trinity college at the university of cambridge [Music] isaac newton who formulated the universal law of gravitation conducted research here martin reese has served as master of trinity college reese has conducted research on supermassive black holes together with lyndon bell [Music] the impetus for his research was the discovery of galaxies whose high-energy cores were emitting powerful radio waves [Music] well there were various alternative theories about what might be happening in the centers of the galaxies which are putting out a concentrated high source of power and these ideas included a very dense cluster of stars a very massive star a binary supermassive object etc and i realized that if you followed forward the likely evolution of any of these objects they would all have no alternative to becoming a big black hole [Music] so any object emitting sufficiently high amounts of energy will inevitably become a supermassive black hole how then are supermassive black holes born the reese diagram as it was called charted the possible roots [Music] in the 30 years since the wreath diagram was published there has been a succession of discoveries of supermassive black holes at the same time the study of their birth has also been progressing one scenario suggested by reese was the consolidation of several smaller black holes [Music] at the end of their lives stars explode forming relatively small black holes hundreds of millions of them may cluster together merging into one supermassive black hole [Music] this is nasa's space-based chandra x-ray observatory chandra has been examining a region where black hole consolidation is thought to be taking place [Music] galaxy ngc 6240 is located 400 million light years from earth actually two galaxies are colliding there as chandra examines their galactic cores two bluish white spots appear [Music] they are both massive black holes one at the center of each galaxy this blue region here is a blow up of the center and you can see there are two little sources there one brighter and one a bit fainter but each of those when we look at the spectrum shows a very characteristic sign that this is just emission from a supermassive black hole in each case which has never been seen before until we have the beautiful chandra image and could separate the two two black holes in close proximity to each other but they cannot soon merge [Music] rather like the earth and the moon in their perpetual dance the two black holes orbit about each other without colliding so what about reese's concept of black holes merging to form a supermassive black hole masayuki umemura uses a supercomputer to create simulations of black hole mergers [Applause] here he simulates the behaviors of 10 black holes of equivalent mass the first consolidation happens far sooner than expected it takes only 50 million years [Applause] the process repeats within about 500 million years five black holes have merged into one let's look at our actual universe there are galactic collisions and mergers all over the place and when galaxies merge the thinking is that their black holes merge too [Music] wherever galaxies cluster there's bound to be a cluster of black holes that means a process of consolidation of black holes this conforms to actual observations of our universe [Music] [Applause] a secondary diagram scenario has a seed black hole becoming supermassive by swallowing up gases and stars in that scenario the monster is born by gulping down an unbelievable quantity of gases equivalent to hundreds of millions of our sun [Music] the gases are sucked in with so much force that the friction produces incredible heat that violent process emits intense light and x-radiation and blows away surrounding gases the result is that there are no more gases to feed on and the black hole ceases to grow [Music] but how is it that such a huge quantity of gases could be sucked in in the first place [Music] gases that are being sucked in blowing away other gases ken alsuga studies this contradiction he has found a particular mechanism within black holes by which they can continue to draw in vast amounts of gases he's prepared a simulation of one scenario for how supermassive black holes may be created as a black hole sucks in gases it generates magnetic field lines which penetrate the surrounding gas disk like hoops thus embedded they are then distorted by the swirl of the disk as the disc swirls the magnetic field lines are caught in a spiral vortex twisted and coiled like a spring this is a plasma jet a portion of the disk's gases charged with energy such as light shoots out in opposite directions perpendicular to the disc any remaining gases are sucked into the black hole which grows [Music] foreign hubble has captured this actual image of an intense jet erupting from the center of a galaxy [Music] the gas guzzling scenario for supermassive black hole creation as outlined in the reese diagram thus seems persuasive [Music] martin reese developed several theories of supermassive black hole formation one was by the continuing consumption of gases another was by the consolidation of smaller black holes but the reese diagram indicated a third possibility as well [Music] under this third scenario just after the creation of the universe large clouds of gas condensed into supermassive black holes directly without first becoming stars at all [Music] recently evidence for this third scenario has also come to light by combining information from the chandra x-ray and hubble space telescopes priyan natarajan hunts for supermassive black holes created at the inception of the universe [Music] these far-off galaxies were photographed by hubble among those circled on the screen are some that are 12 billion light years away they are small galaxies born immediately after the universe itself some 200 of them have been identified [Music] here's one as perceived by chandra [Music] and it already has a supermassive black hole in it was surprised to discover that almost all 200 of them had supermassive black holes in them if so many supermassive black holes were already present immediately after the creation of the universe then that lends powerful support to the third scenario in the reese diagram so just as we think the a gas cloud that is collapsing could make the first star reasonably easily the conditions that you need for making a black hole seed directly without forming a star instead of forming a star also exist in the world early universe efforts are also underway to confirm the third reese diagram scenario computationally i think it is the first time that there is a model showing that it is possible to produce a precursor of a big black hole in the form of the supermassive planet this is a giant gas cloud 100 light years in diameter seventy thousand years after it formed into a gas cloud its gases were compressed into a disk one light year across [Music] the gas disk was equivalent in mass to one hundred thousand of our suns it then condensed further compressed by its own weight giving rise to a supermassive black hole [Music] so the third scenario in the reef diagram going directly from gas cloud to black hole is a real possibility studies of the origins of these supermassive black holes are ongoing the latest research reveals that the supermassive black holes do not simply grow fat consuming everything nearby surprisingly they exert a huge constructive effect on the space around them [Music] what these remarkable monsters call home is a galaxy's core [Music] more specifically it's inside the concentration of stars called the bulge the shape and size of the bulge varies with each galaxy [Music] john cormundy has investigated the relationship between the mass of a bulge and of its supermassive black hole [Music] the first galaxy he observed was andromeda the supermassive black hole here is equivalent to 150 million solar masses the bulge is approximately one thousand times greater in mass [Music] next he looked at the sombrero galaxy the black hole here is one billion solar masses the mass of the bulge is approximately one thousand times that [Music] plotted on a graph coordinating the masses of the bulges with those of the black holes the galaxies form a nearly straight line in most galaxies the black hole to bulge ratio of masses is one to one thousand this strong relationship between the mass of supermassive black holes and their galaxy's bulges surprised many scientists we know that when gas densities get very big you get a burst of new stars being formed and so at the same time when this burst of stars is making the bulge the rest of the gas is being fed to the black hole and making the black hole bigger so you get lots of new stars and you get higher mass black hole and the two correlate [Music] a galaxy comprises hundreds of billions of stars it turns out that at the galactic cores the black holes and the bulges have a deep interrelationship a giant bulge will correlate with a giant black hole a small bulge with a small black hole [Music] this strange law of outer space may mean that galaxies and black holes evolve together andrea guezz discovered the supermassive black hole at the center of our own milky way galaxy she also found evidence that it performs an astonishing function within the galaxy's bulge we've had one surprise after another in our study of the center of the galaxy what we see is that they're very massive stars which tells us that they're very young stars and the last thing you expect near a black hole is to find a very young star because black holes are very inhospitable to star formation they should just tear apart any cloud that might eventually become a star so you really don't expect to see young stars baby stars near a black hole and he had all the stars that told us there's a black hole or the ones we predicted shouldn't be there so it's one mystery after another near the supermassive black hole at the center of the milky way guess found many baby stars this suggests something astounding that new stars may be emerging from the gases that originally accumulate around a black hole [Applause] [Music] the effect black holes have on surrounding space is not limited to the birthing of stars a project spearheaded by nasa called taunami is endeavoring to capture distant galaxies tanomai involves the participation of radio telescopes in a dozen locations in the southern hemisphere chiefly in australia but also in chile south africa and the south pole one of its targets is a galaxy located 14 million light years from earth centaurus a this is the image they obtained a clear view of a plasma jet violently shooting out from an invisible black hole the jet bursts out at 30 percent of the speed of light analysis of this jet turned up something quite unexpected the jets shooting out of the black hole even escapes the galaxy itself its plume expands for a distance of a million light years [Music] so the black hole doesn't just guzzle down gases it sends out the stuff that stars are made of far beyond its own galaxy the role of the supermassive black holes in the universe is still largely mysterious but scientists are learning more and more [Applause] [Music] [Applause] cosmos looks the same from britain from japan indeed the night sky is the same to all of us and has been the same to all our ancestors throughout human history it's the one common feature of all humanity they've all looked up at the night sky and wandered at it and interpreted it in their own way it's a wonderful story where we found all these extraordinary objects in the universe and we can understand these vast cosmic horizons in a way that our ancestors could only have dreamed of so it's a wonderful story supermassive black holes monsters in the galactic cores [Music] they may gobble up everything around them but they also give birth to stars and send out energy-rich materials into the universe some came into being at the same time as their galaxies and grew along with them he was interested in a galaxy adjacent to the big dipper galaxy m106 a spiral galaxy 21 million light years from earth radio waves had been reported to be issuing regularly from the nucleus of m-106 [Music] [Music] in addition to a 45 meter diameter parabolic dish antenna the nobe yama radio observatory has some world-class instrumentation eight spectrometers capable of minute observation of radio waves [Music] a single spectrometer is sufficient to observe radio waves from the nucleus of a galaxy but to be thorough nakai used two spectrometers for the very center of the galaxy and flank them with the six remaining ones [Music] that decision to use all eight instruments led to the discovery of the century [Music] nakai had simply wanted to put all his spectrometers to some use but the results astonished him there were surprising spikes on both ends of the combined graphs nakai was especially struck by the ones on the left this indicated something moving at high velocities never before observed [Music] [Music] more detailed observations were made using a high resolution telescope they found something remarkable at the core of the galaxy a spinning disc [Music] this was a structure very like the disc formed by gases being sucked into a black hole the spikes recorded by the eight nobeyama spectrometers were from this disc [Music] the disc was spinning furiously 3.6 million kilometers an hour detailed analysis revealed that the mass at its center was equivalent to 39 million of our suns it was indeed a monster black hole [Music] [Music] when his discovery was published in 1995 nakai received a letter the letter read i have been waiting 26 years for such proof and four million times the mass of the sun finally after 10 years of observations it was determined that a supermassive black hole does in fact exist in the center of our galaxy [Music] and it is bigger than was imagined by many orders of magnitude black holes created when stars die are typically 50 kilometers in diameter at most but the one at the center of our galaxy is gigantic [Music] the diameter is estimated to be 24 million kilometers that's like 17 of our suns lined up in a row round this monster black hole russia's so2 a giant blue star at 5 000 kilometers per second about 200 times the speed at which the earth orbits the sun that is a speed made possible only by the immense gravitational pull of a black hole [Music] in the center of our own galaxy but far from earth unfolds a dance of the stars [Music] it was this dancing of the stars that proved the existence of a supermassive black hole it was an idea but you know far out and not very much considered this natural and it remained that way for about 15 years lyndon bell had predicted that a supermassive black hole exists at the center of every galaxy apart from observing the orbits of the stars there's another way to prove the existence of such a black hole [Music] that's to observe the moment when a black hole swallows up stars or gases as gases are sucked into a black hole they first flatten into a disk friction causes them to superheat and to emit intense radio waves if these radio waves can be detected that can indicate the presence of a black hole [Music] the largest telescope in the world for detecting extremely high frequency millimeter band radio waves is the 45 meter radio telescope at the national astronomical observatory of japan it was in fact a japanese scientist who first proved lyndon bell's theory that a supermassive black hole lies hidden in every galaxy it happened in 1990 21 years after lyndon bell's prediction now masa nakai was working at the nobeyama radio observatory studying gases at the centers of galaxies [Music] shine much more clearly [Music] guess who did not yet have adaptive optics was at a disadvantage [Music] she minimized atmospheric fluctuations by restricting exposure time in imaging the stars [Music] meticulously she charted their movements success or failure depended on choosing the right stars to follow [Music] at first both teams were following a star designated s01 [Music] but guezza's attention was drawn to another star another star which people were very excited about in the earliest days was so1 it was the star that was moving fastest initially but it was so2 that as it got closer to the black hole has become the fastest moving star that we've known about this graphic represents guess's findings knowing that stars orbit the center of the galaxy was not enough to prove the existence of a black hole [Music] in january of 2002 another star designated so2 was observed to be behaving strangely [Music] it was executing a blindingly fast and tight orbit clocked at 5 000 kilometers per second as if being swung violently around and around [Music] these were incredibly exciting times because of course at every stage of this experiment people said you can't do it or what you're seeing isn't um what you should be seeing so we initially saw that they were moving fast and people said well these stars aren't bound to the galaxy you're not going to see them curve yet so2 was indeed curving in a rapid orbit [Music] this is an actual imaging sequence exhaustive analysis showed it to be a giant star with a mass equivalent to 10 suns [Music] the only thing that can make stars move that fast is a lot of mass these stars are moving because there's a lot of gravity and the only thing that makes that much gravity in that smallest space is a supermassive black hole with their adaptive optics the strange behavior of so2 had not escaped the notice of the european team either they succeeded in imaging so2 at around the same time [Music] of course that was the moment everybody was extremely excited about that we saw wow that orbit is proving there must be a mass and we can measure the mass we can actually calculate the mass it's an easy calculation any student can do it and the result is extremely fascinating this mass which we are seeing in these images is is by pointing your telescope at the center of the galaxy and using a technique that allows you to see the stars around the black hole so here's the black hole and what you want to do is we want to be able to see a star you want to be able to see a star make a complete orbit around the center guests followed the movements of the stars for years plotting their trajectories if they were in fact orbiting some unseen object then that would be proof of a black hole [Music] the center of the milky way however is 26 000 light years from earth ascertaining the movements of stars around a point so far off in space is no easy matter [Music] mauna kea hawaii home to several giant telescopes [Music] ghez used one of the observatories on this summit the keck observatory the keck has two of the largest telescopes in the world with primary mirrors that are 10 meters in diameter [Music] guess's observations here began in 1995. but guess and her team were not the only ones searching for a supermassive black hole in the center of our galaxy [Music] a european team based in the heart of germany had also been hunting the same monster the leader of these star trackers is stefan gillessen they have a 10 meter telescope we have a 8 meter telescope so our telescope is a bit smaller however we are on the southern hemisphere where the galactic center is visible for more hours so we can observe from february to october the european team conducts its observations at the paranal observatory in chile the vlt array there comprises four 8.2 meter telescopes but even with such advanced technology success is elusive [Music] the problem is earth's atmosphere [Music] atmospheric fluctuations blur the stars [Music] april 2002 the european team installs epic making new equipment [Music] from the vlt at paranal they shoot laser beams into the night sky to measure and adjust for those atmospheric fluctuations their special equipment succeeds in doing just that the new method is called adaptive optics [Music] it brings the stars into focus [Music] corrected for atmospheric fluctuations the stars [Music] the black hole is a bizarre space object defined by the absence of everything except gravitational force how do scientists wrap their minds around it it's complicated seriously massive objects warp the fabric of space the heavier the star that is the greater its mass the greater the distortion [Music] so light which would otherwise travel in a straight path gets bent [Music] if a star of any given mass shrinks sufficiently its density increases until its local distortion of space is infinite [Music] that's a black hole a border develops separating the black hole from the space around it once this border has been crossed going into the black hole even light cannot escape [Music] border diameter is determined by the weight of the compressed mass a hole with the same mass as earth would be merely two centimeters across something the mass of the sun six kilometers that's considered the size of the black hole black holes are created the instant stars die [Music] let's say a star 20 or more times larger than our sun reaches the end of its life and explodes [Music] the star's own gravity then causes its remaining core to implode infinitely becoming a purely gravitational force when a black hole is born foreign [Music] so [Music] [Music] [Music] [Music] [Music] [Music] so [Music] [Music] [Music] so so [Music] so [Music] so [Music] so [Music] so [Music] so so [Music] so [Music] foreign [Music] this

Channel: The Universe & Space

Views: 71,484

Keywords: knowledge, Science, The Universe, Space, Solar System, Astronomy, documentary, cosmos, planets, stars, planetary, how the universe works, Secrets of the Universe, Formation, Earth, Space Discovery Documentary, how the universe works formation and evolution

Id: BgqUu0rLCMQ

Length: 220min 4sec (13204 seconds)

Published: Mon Sep 19 2022