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  • Our universe, the galaxies, the solar system, our home planet earth

  • - land, sea, air, life

  • - where did they all come from?

  • Look up into space from our planet

  • and what you see is a vast cosmos - teaming with billions of stars and galaxies.

  • Turn back the clock over 13 billion years and our universe was a very different place,

  • back then it was small that it could fit inside the palm of your hand.

  • Form this infant universe everything would be created

  • - stars, galaxies and the building blocks of life itself.

  • the calcium in our bones, the iron in our blood

  • the atoms for the air we breathe - the water we drink

  • the raw materials for our cities and machines

  • Naked Science takes a journey through space and time

  • to discover how the universe was born

  • and how it created everything in our world

  • - and how eventually it will die.

  • Everything we see around us is made of matter - atoms and molecules.

  • Take this car - it's a 1956 Ford Fairlaine Convertible.

  • It's constructed from many different materials like steel, rubber and glass¡­

  • Go deeper and these materials are made up from combinations of elements like iron, silicon, chromium and carbon

  • Each and every atom that makes up this car were created by our growing universe.

  • Physicist Laurence Krauss studies how the atoms we see on our planet have come to be here

  • We really are part stardust and part big bang dust.

  • Most of the atoms in our body are from the cores of stars

  • but some of them have been around from the earliest moments of the big bang.

  • So we really are truly cosmic individuals

  • Each and every atom was created over billions of years as our universe evolved.

  • So when we look at this car, of course, all the atoms in this car came from stellar explosions,

  • from supernova processes and from stellar evolution,

  • but they were created at different times during the evolution of the Universe

  • To understand how the universe made all the raw material we see here on Earth,

  • we need to take an incredible journey

  • and travel back through space and time to the moment our universe was born.

  • In the beginning there was nothing.

  • No space, no time

  • And then there was light.

  • Suddenly a tiny speck of light appears - it was infinitely hot.

  • Inside this tiny fireball was all of space

  • This was literally the beginning of time.

  • The cosmic clock was ticking - time could flow and space expand.

  • At the earliest moments of the big bang, if you take it back to T=zero,

  • everything in our universe, everything we can see, all the matter and all the energy in all of the galaxies

  • was once contained in a region smaller than the size of a single atom today,

  • The idea that our universe was once tiny originated from the brilliant work of American astronomer Edwin Hubble.

  • Back in the 1920's most astronomers believed that everything visible in the night sky were stars

  • and they were part of our galaxy - the Milky Way

  • But Hubble wasn't convinced.

  • He studied a swirling cloud of light called the Andromeda Nebula and showed that it was a star city

  • another galaxy far outside of our own galaxy

  • He showed that these 'other' galaxies were speeding away from ours

  • and the further away they were, the faster they seemed to be moving

  • The universe was expanding

  • and if the universe was expanding, then at some point in the past it must have been smaller

  • - much smaller

  • and that it must have had a beginning.

  • The idea of the 'Big Bang' was born.

  • Theoretical physicist David Spergel is a Big Bang expert

  • The Big Bang theory is not really a theory of how the Universe began;

  • it's really a theory of how the Universe evolved

  • No-one knows exactly what happened during the Big Bang

  • but scientists do know that a fraction of a second after the universe was born

  • this tiny super-hot fireball was already starting to expand

  • We don't know how the Universe began,

  • so we start our story when the Universe was a billionth of a billionth of a billionth of a billionth of a minute old

  • Pretty young, the Universe was the size of a marble

  • Less than a trillion trillionth of a second after the Big Bang

  • the marble sized universe was very unstable and underwent an enormous growth spurt.

  • During this period of incredibly rapid expansion,

  • Space itself was expanding faster than the speed of light.

  • In the same way that this hot glass ball inflates, so did the baby universe

  • expanding in all directions at once and as it expanded it cooled.

  • A trillion trillionth of a second after the Big Bang the Universe was small enough to fit inside the palm of your hand.

  • A tiny fraction of a second later it was the size of Mars

  • Another fraction of a second and the baby universe had grown to 80 times the size of the earth.

  • A trillionth of a second after the Big Bang and our newborn universe was still expanding

  • But it didn't contain matter - it was pure energy

  • Einstein's famous equation E=mc2 showed that mass and energy are interchangeable

  • It gave us the knowledge to build weapons of mass destruction.

  • It also revealed how the universe created the first matter.

  • When a nuclear bomb explodes

  • a tiny amount of matter is annihilated and converted into energy.

  • In the baby universe the exact opposite happened.

  • It converted pure energy into particles of matter.

  • But there was a problem.

  • The universe created both matter and its arch rival anti-matter

  • - and when these two met they obliterated each other.

  • The infant universe was a war zone - a battle to the death between matter and antimatter

  • If they mutually annihilated each other the universe would remain full of energy with no galaxies, stars, planets or life

  • Fortunately for us there was an imbalance.

  • For every 100 million anti-particles formed, there were 100 million and 1 particles of matter

  • But there was that one extra particle of matter left over in each volume,

  • and that was enough to account for everything we see in the universe today,

  • This tiny imbalance led to all matter we see in the universe

  • - galaxies, stars, planets, - even convertibles and ourselves.

  • Astrophysicist Carlos Frenk from Durham University in England explains.

  • We are a little bit of debris left over from the annihilation of matter and antimatter;

  • we're the leftovers of that process.

  • If the Universe had not developed this slight asymmetry between matter and antimatter

  • the Universe would have been completely boring, there would be no structure, there would be no galaxies, there would be no planets,

  • Quite what this newborn Universe was like has challenged cosmologists since the Big Bang was first put forward.

  • Now in one of the biggest laboratories on Earth

  • they are able to recreate the conditions that almost certainly existed an instant after the Big Bang.

  • It's called the Relativistic Heavy Ion Collider - RHIC for short

  • and it's located at the Brookhaven National Laboratory on Long Island.

  • It's like a time machine - taking us back to 10 millionths of a second after the Big Bang

  • Here scientists like Todd Satogata accelerate subatomic particles close to the speed of light and then smash them into each other.

  • The particles race around this 2.5 mile long circular tunnel in opposite directions 78,000 times a second¡­

  • and then collide inside this giant detector - bigger than a 3 story house¡­

  • When they smash into each other they generate incredible heat - just like the real infant universe

  • We believe the early universe was extremely hot billions of times hotter than the centre of the sun

  • and what you're doing smashing these nuclei together is melting matter, creating matter hot enough to give us a glimpse of what the very early universe was like

  • When the particles collide they break open and throw out a shower of even smaller particles

  • It's a bit like discovering what cars are made of by watching them smash into each other

  • You can race two race-cars together and smash them into each other head-on,

  • and when you do that multiple times you start to see different patterns coming out,

  • a tyre comes out here, a radiator comes out there,

  • and before long you can start to conclude that a race-car is made up of these certain pieces.

  • What the scientists at Brookhaven have discovered is that within these superheated collisions a completely new form of matter appears.

  • And this matter contradicts the previous theories on the nature of the early universe.

  • Because it's not a gas - it's a liquid.

  • It was super hot - 100,000,000 times hotter than the surface of the sun

  • There was so much energy inside the young universe that the particles vibrated so fast that it had no stickiness

  • there was no friction and it flowed perfectly.

  • This liquid is perfect, it has no viscosity, in some sense it would be the perfect motor oil except it's a trillion degrees hot.

  • Inside the collider this amazing liquid Universe exists for only a tiny fraction of a second.

  • The Brookhaven scientists have succeeded in recreating conditions that existed over 13 billion years ago

  • Despite the universe being a perfect liquid - it was in turmoil.

  • It was full of subatomic particles smashing into each other releasing more and more energy

  • There was so much energy that unless the particles slowed down they would never bond and create atoms

  • - the building blocks of matter

  • - and the universe would never create the galaxies and stars or even us.

  • The universe is now one millionth of a second old

  • and has expanded from smaller than the size of an atom to 8 times the size of the solar system

  • After the incredible turmoil of the first millionth of a second the Universe was now relatively calm

  • Over the next three minutes the expanding cosmos cooled sufficiently for protons and neutrons to bind together

  • and form the first atomic nuclei: hydrogen and helium.

  • These were not yet proper atoms

  • They were missing a vital ingredient - the electron

  • In the hot baby universe there were plenty of electrons around,

  • but there was still so much heat and energy the electrons were moving too fast to form bonds

  • And it would stay that way for over three hundred thousand years.

  • 380,000 years after the Big Bang the universe had expanded to the size of the Milky Way.

  • It had cooled from billions of degrees Fahrenheit to a few thousand

  • As it cooled, the electrons slowed down.

  • The universe was now ready to make its first true elements.

  • One of the scientists who discovered this critical moment in the story of the universe was Arno Penzias.

  • 1963, 30-year-old Penzias and his 27-year-old colleague Robert Wilson began work on a new antenna in New Jersey.

  • Initially they were only studying cosmic radio waves

  • - but they would stumble on one of the greatest discoveries of all time.

  • As they started to test their equipment, they detected an unexpected background noise

  • It was an additional signal and it appeared to be coming from the sky,

  • we eliminated very carefully the ground, even the solar system,

  • because we did this winter to summer, seasonal variation,

  • man-made sources of equipment, all these things were eliminated.

  • In desperation, the two scientists began to wonder whether the strange signal might have another, more earthly, origin

  • They found there were pigeons roosting in the antenna, and it was covered with droppings

  • They wondered if the pigeons were the source of the strange signal.

  • There was only one solution: the droppings and the pigeons would have to go

  • When we finally got around to removing the pigeon droppings, we also had to remove the pigeons

  • and that was a difficult problem because they turned out to want to come back and so we mailed them off to another site

  • But even with the troublesome pigeons gone, the mysterious signal would not disappear.

  • so we were left with the inescapable conclusion that this radiation was coming from the sky.

  • I could not account for it

  • The strange signal detected by Penzias and Wilson would turn out to be one of the most important scientific discoveries of all time

  • But the explanation for their mystery background noise starts not with sound - but with the birth of light

  • We usually take light for granted.

  • But in the early universe 13 billion years ago, we would see nothing at all.

  • Light was trapped. The universe was foggy.

  • But as the universe continued to expand and cool the electrons slowed down

  • Protons then grabbed these calmer electrons to form complete atoms of first hydrogen and then helium

  • The universe was suddenly much less crowded with electrons

  • The fog lifted and light was no longer trapped.

  • It hurtled out across the universe - creating a blinding burst of light.

  • Had we been there we would have suddenly seen this opaque Universe become transparent,

  • suddenly the fog would lift and we would see a flash of light coming from everywhere around us.

  • It must have been a spectacular moment.

  • Over time, this burst of light dimmed and cooled and became microwave radiation.

  • It was this faint 13 billion year old microwave signal that Penzias and Wilson picked up on their antenna.

  • What they heard was the quiet echo of the moment the universe formed the first atoms

  • It's really the light from the origin of the Universe

  • If you have an old FM receiver, ¡­ if you tune between channels,

  • turn the knob and it doesn't capture it and pop to the station,

  • you get to a part where there's not, you hear a fffffff¡­. that's what we call noise.

  • If you have a good radio set, one half of one percent of that fffff¡­ is actually the sound of the Big Bang.

  • And we can also see the moment when the first elements were created

  • If our television is not tuned to a station, a tiny fraction of the noise is radiation from 13 billion years ago

  • But this radiation is not the only reminder of the birth of the Universe - even the water we drink is a memento

  • And it's kind of amazing to think that every time we take a drink of a glass of water,

  • we're drinking in atoms that have been around since the Big Bang - the hydrogen atom.

  • Over the next millions of years the young universe continued to expand, cool and get dark again

  • So far the Universe had only made hydrogen and helium atoms

  • but the world we live in is made from more than a hundred different kinds of elements

  • Without them the universe would remain a very boring place made up of only gas

  • a place where complex matter - like planets, cars and people could never develop.

  • The universe needed to get hydrogen and helium atoms to fuse.

  • And to do that it needed to make stars

  • The universe was now 200 million years old and billions of light years across.

  • Its temperature had dropped so far that it was colder than liquid nitrogen - minus 367 degrees Fahrenheit

  • It was also dark.

  • It would have remained a very gloomy place full of gas

  • but without galaxies, stars or planets if it hadn't been for one thing:

  • The baby Universe wasn't born perfect.

  • Carlos Frenk has created an amazing 3-D simulation of how the early universe evolved

  • It shows that when the Universe emerged from the Big Bang it was uneven.

  • Little cracks appeared which were very, very, very tiny, very, very small,

  • and it was this rash in the face of the baby Universe that later developed into the patterns that we see in the galaxies today

  • Without these cracks, the universe would have been a very dull place.

  • The first clues as to how these cracks developed into galaxies and stars

  • came when other scientists started to examine the Big Bang radiation first discovered by Penzias and Wilson

  • So Penzias and Wilson saw was this radiation was, as far as they can tell uniform,

  • What cosmologists then did for the next 25 years was work very hard to try to find tiny variations

  • And find them they did using WMAP

  • a space probe designed to detect and analyze in detail variations in the back ground Microwave radiation

  • Launched in 2001 the $150 million probe was fitted with some of the most sensitive instruments ever carried into space.

  • Our eyes detect only visible starlight

  • But WMAP can 'tune' into the invisible microwave radiation.

  • Once in orbit round the sun it picked up the faint radiation that has been rippling around the universe since the dawn of time.

  • So when we look at the cosmic background radiation

  • we're looking at this radiation that's been streaming towards us since half a million years after the Big Bang.

  • Initially the 'microwave universe' looked very dull and seemed to be the same everywhere

  • But when WMAP turned up the contrast: the results were spectacular.

  • The baby universe wasn't smooth and boring at all - it was full of fluctuations

  • These tiny fluctuations tell us what the variations in density, how much stuff there is, and how it varies from place to place

  • these denser regions are going to collapse to form clusters of galaxies and super-clusters and galaxies themselves

  • These low density regions, these will grow and become the empty regions between galaxies,

  • so this picture, really is our connection between the Universe when it was a baby half a million years old,

  • to the Universe today, 13.7 billion years old

  • These tiny imperfections in the fledgling Universe would become galaxies and stars

  • And this is one of the most amazing propositions in physics

  • the idea that galaxies like a Milky Way that contain a hundred million stars once began life as a tiny little crack in the fabric of the Universe

  • The material in these cracks was filled with swirling clouds of hydrogen atoms

  • The voids between the clouds grew bigger and bigger.

  • The gas clouds got denser and hotter.

  • Gravity pulled the gas clouds together on filaments - like beads on threads of a web - a cosmic web

  • Where the giant filaments formed large globs, stars and galaxies would grow.

  • As the Universe evolved, gases were able to condense into clouds which collapsed to form stars

  • The stars settled into a rotating disc that was later to become a spiral galaxy like the Milky Way.

  • Over millions of years the hydrogen atoms clumped together and heated up.

  • The atoms began fusing and releasing energy and the gas clouds started to burn brightly

  • Eventually a star was born.

  • All over the universe, millions of stars ignited for the first time.

  • The appearance of the first stars would have been a truly spectacular event

  • Had we been there we would have really seen fireworks,

  • individual, enormous flashes of light generated as the stars are born and burnt themselves out.

  • The universe has expanded many trillions of times its original size

  • It was full of new born stars made of hydrogen and helium.

  • These young stars were nothing like our own Sun

  • They were very unstable.

  • But it was their instability that would make the universe a more interesting place

  • because deep inside each new star something amazing was happening.

  • They were creating new elements

  • The idea that stars build atoms came from the British Astrophysicist Sir Fred Hoyle

  • - one of the greatest astronomers of the 20th century.

  • Hoyle didn't believe that the universe began in a single explosion.

  • In fact he coined the name "Big Bang" as a term of derision.

  • Hoyle wanted to know where the elements heavier than hydrogen and helium came from

  • He figured out that stars acted like nuclear reactors

  • working a bit like a Hydrogen bomb in slow motion

  • But many billion times more powerful. And their "nuclear waste" was new elements.

  • But it would take years before scientists were able to confirm his theory by analyzing the light from stars

  • Each element emits light at a particular frequency when heated up.

  • Imagine a sodium street lamp - it emits light of a yellow colour specific to sodium

  • It's the same with stars.

  • Take our sun.

  • If you break the light down into a spectrum you can see lines like a barcode corresponding to the elements

  • Each element has specific colors helping scientists identify elements like hydrogen which emits mainly red light

  • In 1990 NASA launched the Hubble Space Telescope to unravel some of the mysteries of our early Universe

  • Lift off of the Space Shuttle Discovery with the Hubble Space Telescope, our window on the Universe

  • Hubble promised scientists unprecedented views of the young universe.

  • It would be able to look back through space and time

  • and examine early stars to discover if they were making new elements.

  • But the dream soon turned into the worst nightmare.

  • After it was launched they discovered that Hubble's mirror was distorted - it saw everything out of focus.

  • It needed corrective lenses.

  • And the only way to fix it was to send up another space shuttle.

  • One of the repairmen was astronaut Jeff Hoffman.

  • We were working with a two billion dollar telescope and the last thing we wanted was to break something,

  • and leave it worse off than when we got up there.

  • First the crew of the rescue mission had to capture the crippled telescope.

  • Then execute a repair mission unprecedented in the history of space flight.

  • First they had to open the access doors on the side of the telescope.

  • The one thing about working on Hubble that is very different from working on a car

  • is you look over your shoulder and there you are in space and the Earth is going by below you, the stars above you.

  • The astronauts had to carry out fine detailed work in the most difficult conditions.

  • When you're working in a space suit your hands are encumbered by thick, stiff gloves.

  • It's sort of like working in ski mittens - it was quite a challenge

  • All went well until Hoffman attempted to close the huge access doors.

  • I just had to close up the doors, and when I went to close them and that they wouldn't close properly,

  • The doors were somewhat warped

  • and it took a while for it to sink in - this was very serious.

  • If you can't get the doors closed you lose the telescope.

  • Using improvised tools Jeff and a colleague were finally able to close the doors.

  • It took the team five days to repair the stricken telescope.

  • Cosmologists around the world held their collective breath.

  • They waited to see if the most expensive telescope ever built would deliver what its designers originally promised

  • I well remember New Year's Eve, 1993, December 31st.

  • When my phone rang, and it was an old friend who worked at the Space Telescope Science Institute in Baltimore.

  • He said, 'Jeff you have any champagne left over from your party?'

  • I said, 'Yeah, we still have a half bottle in the refrigerator.'

  • He said, 'Well, crack it open again and drink a glass because we got the first picture back and Hubble works.'

  • This is what Hubble saw - the images were beyond anyone's wildest dreams

  • Hubble captured the final moments of a star's life when it explodes and blows off gas and dust.

  • It also captured interstellar nurseries of new born stars - exploding into life billions of years ago

  • And dark pillars of cosmic dust - millions and millions of miles long

  • - ready to spawn a new generation of stars and planets.

  • But Hubble's true moment of glory was still to come.

  • Over a ten day period in 1995 the mission controllers pointed the telescope at a distant empty patch of space.

  • What emerged was the Deep Field image - a tapestry of distant galaxies.

  • Hubble was looking back in time to some of the first galaxies and stars created.

  • it revealed thousands of galaxies that hadn't been seen before,

  • so the universe became, to our consciousness, far richer after the Hubble deep field,

  • It showed for the first time faint images of galaxies formed just a billion years after the big bang.

  • Scientists then examined the spectrum of light from these distant stars

  • and showed that these early galaxies had already created elements heavier than hydrogen and helium

  • Sir Fred Hoyle may have been wrong about the birth of the Universe but he was absolutely right about the stars

  • The early stars acted like giant thermonuclear reactors creating new elements

  • You can think of the creation of all the elements in this room in some sense, like a car assembly line,

  • because in a car assembly line, each part is sequentially added to the vehicle, until it's complete.

  • Fusion reactions inside these young stars released enormous amounts of energy and heat

  • which forced atoms to fuse to form new heavier elements one after the other

  • Three helium nuclei combined to form carbon

  • two carbon nuclei fused to form magnesium, magnesium to form neon

  • and so on over a period of hundreds of thousands of years until silicon fused to form iron.

  • Iron is a very special atom.

  • The protons and neutrons inside its nucleus are very tightly bound together

  • so that even the extreme temperatures inside the stars couldn't get it to fuse into heavier elements

  • It resolutely stays iron.

  • It was the end of the road - the production line of element building shut down

  • But our universe was still not complete

  • There were all the ingredients to make a glass of water

  • And some of the elements to build part of our convertible.

  • There were also quite a few of the ingredients to make a human being

  • the oxygen we breathe, the calcium in our bones¡­ and the iron in our blood

  • But there still weren't any of the vital ingredients like chromium for our car fender

  • And some metals like Zinc that our bodies can't survive without

  • The universe was about to enter a super creative phase where it produces all the elements heavier than iron

  • To make the missing pieces in our birth of the universe jigsaw would take some of the most powerful explosions the universe has ever seen

  • Our Universe has already celebrated its 500 millionth birthday.

  • There are still another 13 billion more to go before humans appear on the face of the earth

  • Giant new stars have made many of the elements in the world we see around us.

  • But some vital elements are still missing

  • heavy metals like chromium and zinc, and expensive ones like gold and platinum

  • To finish the job, the universe conjures up the most amazing phenomena since the Big Bang

  • Massive exploding stars called 'supernovas'

  • When the giant stars that made the lighter elements ran out of fuel they collapsed in on themselves

  • creating incredible amounts of energy and enormous explosions

  • These explosions were so powerful they could fuse elements even heavier than iron and restart the element production line

  • Tony Mezzacappa from Oak Ridge National Laboratory in Tennessee

  • believes that without exploding stars life itself would not exist

  • Life as we know it certainly would not exist were it not for core collapse supernovae events

  • They are very clearly one of the key links in our chain of origin from the Big Bang to the present day

  • One of the most recent and biggest supernovas closest to our galaxy was seen in the southern hemisphere in 1987

  • When a supernova like 1987A explodes it emits light containing the signatures of the elements within it

  • By examining this spectrum of light scientists can calculate what elements are being forged inside the exploding star

  • Massive stars evolve to an onion-like configuration at the end of their lives.

  • They have an iron core and outside of the iron core are layers of successively lighter elements

  • Inside the iron core, the temperature rises to 8 billion degrees, nearly 300 times hotter than the center of the sun

  • It is so hot the iron atoms that have sunk to the stars core are torn apart. The core destabilises

  • The cores then collapse on themselves in a fraction of a second, the collapse proceeds to very, very high densities

  • The core collapses at speeds of more than 43,000 miles per second.

  • A volume the size of the earth crunches down nearly 6 times the size of Manhattan in an instant

  • The core becomes super dense.

  • If one were to take one cubic centimetre of that matter, that would be the size of a sugar cube

  • that sugar cube would be so dense that it would weigh as much as the entire human race

  • The core rebounds, like a compressed rubber ball - and launches a massive shock wave.

  • The shock wave hurtles out, smashing through the different skins of the star

  • As it punches through the outer layers of the star, the energy generated restarts the element production line

  • Atoms are smashed together to make brand new heavier elements - all heavier than iron

  • Then the star explodes and the shock wave pushes the shrapnel like debris outwards - further and further into space

  • In a very real sense our lives depend on the stars in the Universe, without their lives and deaths, we would not be here today

  • These astonishing images taken by the Hubble Space Telescope show the aftermath of these giant explosions

  • Nebulae - giant clouds of debris thrown off by exploding stars.

  • Swirling inside are big new atoms - gold, silver, zinc and lead

  • Without supernovas, our world would be a very dull place - and possibly lifeless

  • So I'm sure that, that Paris Hilton doesn't wake up every day, thinking about this fact

  • But really, if it weren't for exploding stars, those 200 million stars that exploded so we could be here today,

  • she wouldn't have anything to wear

  • So if it weren't for those supernova explosions, there wouldn't be any bling

  • Nine billion years after the Big Bang and all the ingredients are in place for life as we know it

  • The universe has grown up into a vast, complex place made up of billions of galaxies and uncountable stars.

  • In a quiet corner of the Milky Way, a mass of dust and gas begins to accumulate

  • It's full of the rich debris left over from one of the massive supernovae

  • and when it reaches a critical mass it begins to burn brightly

  • a star is born - our own star, the Sun

  • What's left over forms a disc of swirling debris in orbit around the new star

  • The gas and dust that make up this ring collide, pulled together by gravity.

  • The clumps of dust and gas become bigger and bigger.

  • Planets form¡­ One of these planets is our earth.

  • Over the next 500 million years our planet slowly generates a protective canopy of gas - the atmosphere.

  • The first life appears. Just single cells at first

  • but as the aeons pass those tiny single cells evolve into plants and animals - and eventually humans.

  • We tend to disassociate ourselves from the universe, but that of course is completely wrong,

  • we are a vital part of the cosmos,

  • and so when we talk about the origin and evolution of the universe,

  • we're actually talking about the origin and evolution of ourselves.

  • Everything we can see on our planet was either made in the Big Bang or inside a star

  • Scientists like Krauss believe they now know the genesis of every atom that has created the world we live in

  • These atoms have been around since the dawn of time,

  • and when I was young my mother used to tell me, don't touch that, you don't know where it's been,

  • and she would have been amazed.

  • But this is not the final chapter in the story.

  • After almost 14 billion years the universe has really only just gotten started

  • Now we take a journey into the future to see how it all ends.

  • The universe we live in is nearly 14 billion years old

  • It has created the raw materials for everything we see around us.

  • The stars, the planets, trees, cities - automobiles - even us.

  • Our world is complete. But the universe is still evolving.

  • Scientists have come up with many theories on how it will end.

  • We know our universe began in a Big Bang.

  • What we don't know yet is what the future of our universe is going to be

  • Our universe may end with a bang or whimper, or something even more exotic.

  • One theory suggests that our universe will run out of steam and stop expanding

  • every star, galaxy and planet, every atom will start to collapse

  • ending in a single super dense pinpoint - known as the 'big crunch'

  • To find out if the Universe really is going to crash back in on itself

  • scientists first need to discover if it's still expanding or if it's slowing down

  • Astrophysicist Saul Perlmutter studies the death of the universe by finding beacons in space

  • exploding stars called type 1A supernovas

  • If you have enough of these exploding stars, these supernovae, that you've measured their brightness,

  • so the ones that look fainter and fainter and fainter must be further and further and further away.

  • And so you have some supernovae that little bit brighter, they're more nearby, some that are a little bit fainter

  • so they're a little bit further, and some that are very faint, so they're very far away.

  • Type 1A Supernovas are similar to the supernovas that created the heavy elements.

  • They differ in one important fashion - they always explode with the same exact brightness

  • This is because they are created in the same way

  • Two stars circle each other held together by their gravitational attraction

  • One is shrivelled and super dense glowing with white heat: a White Dwarf.

  • The other star has bloated to an enormous size

  • it's a red giant that is burning the last of its fuel

  • As the two stars orbit each other, the White Dwarf sucks gas from its companion and begins to grow year after year

  • When it is precisely 1.44 times the mass of our sun,

  • the White Dwarf crumples, collapses then explodes releasing a blinding burst of energy

  • Every Type 1A supernova explodes at the same 'tipping point'

  • and so are equally bright and visible across the vast distances of the universe

  • Perlmutter needs to find hundreds of Type 1A supernovae and then measure how fast they are moving away from us

  • By comparing the positions and dates of all these supernovas stretched over space and time

  • Perlmutter can calculate whether the universe is slowing down

  • His results are a shock.

  • The expansion of the universe isn't slowing down at all.

  • When we began the project of course the goal was to find out how much the Universe was slowing down

  • Now when we actually started looking for data it looked like the Universe wasn't slowing enough to come to a halt,

  • and in fact it wasn't slowing very much at all

  • and in fact when we finished the analysis it looked like it wasn't slowing, period, it was actually speeding up in its expansion

  • Perlmutter's astounding discovery means that the universe will not grind to a halt,

  • then crunch back down into a pinhead of super dense matter.

  • Quite the opposite - it will continue to expand faster and faster

  • Our Universe is literally flying apart.

  • The expansion of the universe will accelerate at ever faster and faster rates

  • Until literally, everything will get ripped apart,

  • not just galaxies, but eventually, matter, the earth, all the objects, stars,

  • the earth, planets, people, atoms, in a finite time, will get ripped apart.

  • Long after our Sun has burned out; 100 billion years in the future galaxies will pull apart.

  • The universe will be made up of isolated stars, which are running out of energy.

  • Some will become white or brown dwarfs - others will collapse into neutron stars or black holes

  • Then thousands of trillions of years after the Big Bang, even the black holes will evaporate

  • and all matter will decay to its basic ingredients Atoms will fall apart.

  • And even protons - the building blocks of atoms - will decay.

  • The most likely future is perhaps the most dismal one, where the universe becomes cold and dark and empty.

  • As the universe continues to expand and the galaxies speed apart from each other

  • - space will become empty and dead.

  • Our own cluster of galaxies, will be moving away from us faster than the speed of light, and will disappear from the night sky.

  • Eventually everything will just sort of wind down, and that's the end of things

  • Finally the universe will die and all that will be left is a cold dark and lifeless space

Our universe, the galaxies, the solar system, our home planet earth

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Birth of the Universe, National Geographic : Learn English!

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    VoiceTube に公開 2013 年 02 月 26 日
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