Horizon (1964) s47e04 Episode Script

Can We Make a Star on Earth?

1 The sun is 93 million miles away.
And yet it can illuminate the surface of the Earth.
You can fit a million Earths inside.
The surface temperature is 6,000 degrees.
At its core, it's 15 million degrees.
It loses 4 million tons of mass every second.
That mass is turned into energy and we feel it as heat.
The sun is powered by the strongest force in the universe.
And, as a physicist, I believe that our long term future depends on us learning to do the same.
That's why, across the world, teams of engineers and scientists are stepping into the unknown.
You are looking inside the Star Chamber.
We're gonna discharge about 26 million amps.
That little ball starts collapsing at a million miles an hour.
They're all united in a single quest.
So, it's about to get dangerous, so we'd better take off.
It's the greatest engineering challenge that we have yet faced - to build a machine that will make a star on Earth.
Sunrise, dawn.
That moment when night becomes day that had an immense significance for our ancestors.
The sun sets the rhythm for life on Earth.
Each day it returns and the world awakens.
I think in one way we've lost that sense of significance of the sunrise in our modern, electrically-lit world.
But, in another way, that's been replaced by modern science's understanding of the sun as a violent, majestic and massive object.
Andas is often the way when you understand the true nature of something, then that's all the more reason to revere it.
The sun bathes our planet in energy.
It's so powerful that in just one second its light could supply the United States with energy for a million years.
And hidden at its heart is the power source - all 385 million, million, million, million watts of it.
It's a power source that lights up every one of the 100 billion stars in our galaxy.
So the universe is awash with effectively limitless amounts of energy.
Then you have to ask the question, is there a way of producing the energy that you need to run all this for everyone in the world, in a way that doesn't damage the planet? As a physicist, there is a way.
In principle, there's a way.
It's the same way that stars produce energy.
It's nuclear fusion.
Nuclear fusion is nature's power source, a process that has kept our sun burning without fail for five billion years and counting.
The question I want to ask in this film is, is it possible that fusion is a power source for the future? Can a nuclear fusion power station be constructed? And can we do it sufficiently quickly that we can use it to address the pressing and serious energy crisis that we've got today? It sounds like science fiction.
But in the heart of Oxfordshire, they've been busy lighting little stars for over 30 years.
- So, what's the advantage of fusion? - Well, the chief advantage of fusion is probably it doesn't produce carbon dioxide, so no global warming gasses.
'The Joint European Taurus, or JET, 'is the world's largest experimental fusion reactor where each day 'they initiate this beautifully simple nuclear reaction.
' So it seems to me that, in principle, we have the ideal energy source.
It couldn't be better, could it? It had one downside, that it's very hard to do.
You had to create the conditions that are 10 times hotter than - the centre of the sun to initiate these reactions.
- HAD, you said? But, right, we've done it - in the machine that you're about to look at.
Seven, six, five, four, three, two, one.
There it goes.
'Scientists have learned how to create and hold star matter, 'a cocktail of gasses heated to 100 million degrees.
'For a moment, a little piece of the sun springs into life on earth.
' It's amazing.
So we're looking at the conditions, ten times the conditions that are present in the centre of the sun? They're ten times the temperature of the sun? - Absolutely.
- In that reactor? - It's incredible and it goes on for all those seconds, you know, it's impressive.
The remarkable thing is it seems routine.
I'm sure there's a lot of work gone into making it routine.
- Yeah.
- That's my sense of this.
- As people have got used to it.
Of course, there are times when we actually put the real fuel in there and a shot like that will be producing lots of fusion power.
Very exciting, when that happened.
To this day, JET holds the world record for fusion power.
Yet, despite decades of research and this fleeting glimpse of fusion, no electricity will ever make it from here to the grid.
Learning how to produce useful power from fusion remains beyond our capabilities.
One thing we do know is that, in nature, fusion only occurs in one place - right in the centre of stars.
Vast celestial power houses, like our sun.
The road to understanding the sun has been long.
And it all began with a remarkable piece of deduction.
So, how could you begin to find out what the sun's made of? I mean, you can't go there.
It's a long long way away and it'd be a bit hot when you arrived.
Well, actually, the story began back in the 1660s with the British physicist Isaac Newton.
He used one of these, a prism, to look at the light from the sun.
What Newton found is that if you look at light through a prism then it splits up into its component colours.
It makes a rainbow.
Now, at the time, Newton didn't appreciate the full significance of his discovery, or at least the usefulness of it.
Through the 18th and 19th centuries, chemists and physicists looked at the light in real detail.
And what they noticed was that the spectrum isn't continuous.
It has pieces missing, it has black lines through it.
This was a puzzle.
Why was some of the sun's light missing? The answer is beautifully simple.
Each chemical element in the sun absorbs light to produce its own unique pattern of black lines, known as absorption lines, in the solar spectrum.
A kind of fingerprint for every element in the universe.
That leaves you with an interesting possibility.
If you look at the light from the sun and you look where the black lines are, then you can deduce exactly what elements are present in the sun.
And today, from many precision observations of the light from the sun, using just this technique, we know that the sun is 75% hydrogen, 24% helium and about 1% the heavier elements that make up the universe.
Scientists had discovered what the sun and stars were made of.
But they were no closer to figuring out how something made of the two lightest elements in the universe - hydrogen and helium - could emit such vast quantities of energy.
Progress came with the discovery of one of the most famous equations in science.
Now, it took until 1905 and Einstein for the key to the sun's energy source to be revealed.
The equation E=MC2.
Energy equals mass times the speed of light squared.
Speed of light squared, immense number.
It's got 16 noughts after it.
This huge number means that only a small amount of mass contains vast amounts of energy.
Einstein had uncovered a remarkable facet of nature.
Mass is just an incredibly condensed form of energy.
Imagine I took a dollar bill, that's about a gram, and converted that into pure energy.
That is the mass lost in a hydrogen bomb.
So there's one hydrogen bomb's worth of energy in every dollar bill.
When Einstein first wrote down his famous equation, E=MC2, it wasn't realised at first that that was the key to understanding the power of the sun.
It took another 15 years or so for the British scientist, Arthur Eddington, to well, what seems like put two and two together.
But that would be disrespectful to Eddington.
He noticed a result that had again been known for many years.
That if you take four hydrogen nuclei, like these rocks, and you can stick them together to make one thing, to make helium.
And it was known that the helium weighed less.
It was less massive than the four hydrogen nuclei on their own.
Eddington suggested that the sun shines by combining hydrogen into helium, releasing the missing mass as energy.
And in fact we now know that the sun loses about 4 million tons of mass every second as energy.
Now, of course it wasn't clear at the time that Eddington was correct.
But correct he turned out to be.
What he'd actually discovered was the process that came to be known as nuclear fusion.
When Eddington had suggested that fusion might be the process that powers the sun, it was pointed out to him that actually the centre of the sun was not hot enough for fusion to happen, as physicists understood the process at that time.
What you actually need is an understanding of quantum mechanics and that didn't come until later.
But Eddington was so sure of himself that he said, "To those who suggest that the centre of a star is not hot "enough for fusion to take place, I say go and find a hotter place.
" Which is a very polite, British way of saying, "Go to hell.
" Of course, no hotter place was found and Eddington's model for solar fusion was adopted and refined.
But it left a big question - how on earth do you light a star in the first place? A drive-in movie theatre.
Last time I saw one of these was in Grease with John Travolta and Olivia Newton-John.
To find an answer, I've arranged to meet a Californian astronomer called Alex Filippenko who's going to take me back 13.
5 billion years to a time before the stars ever existed.
Remarkably, astronomers have been able to collect light from this time, just 380,000 years after the universe began at the Big Bang.
Oh, wow.
Here we're seeing the launch of WMAP.
'A satellite called WMAP 'was able to take a snapshot of the universe in its infancy.
' The different colours, what do they represent? Yeah.
The reds and blues signify slightly hotter than average and cooler than average regions.
And those correspond with slight differences in density.
'In the denser regions, the primeval constituents of the universe were 'drawn together by gravity.
' So the universe was, at the time of the WMAP image, - was hydrogen, helium? - Hydrogen and helium, that's it.
Because during the Big Bang temperatures and pressures weren't high enough for very long to produce the heavier elements.
'Over time the regions of hot, dense hydrogen and helium clumped together 'to create huge stellar nurseries - ideal places for stars to form.
' These slight little variations in the density led to regions that started collapsing, clouds of gas that started collapsing to form clusters of galaxies and galaxies.
And then, within them, stars could form as well.
'The first generation of stars lit up, 'initiating fusion and bringing an end to the universe's Dark Age.
' That would be a star there, would it, beginning to form? Yeah, that's right.
You're seeing clumps of hydrogen and helium and then gravity, the great sculptor of the universe, causes these things to collapse, forming stars like this one.
'Many of these first stars were giants, 'hundreds of times more massive than the sun.
' 'They burnt their hydrogen fuel quickly 'and died in supernova explosions.
'They were the early chemical factories of the universe.
'From just hydrogen and helium in the beginning, generations of stars 'have created every element we're familiar with today.
' The stars are the fusion reactors that produced the heavy elements of which we are made.
I think it's a wonderful thought, because I look at my hand and that is Well, it's red because there is iron in it and it's made - of carbon and oxygen and that stuff.
- You're made of star stuff.
Quite literally the heavy elements in your body - anything other than hydrogen and helium was produced inside of stars billions of years ago.
We really are children of the stars, created by the simplest of nuclear reactions - fusion.
And now that we understand this remarkable process it offers us a tantalizing prospect.
If we could reproduce the energy generating process at the heart of the sun, if we could build a star on Earth, then our energy generation problems would be over for ever.
For now, though, we continue to rely almost entirely on our sun.
I suppose in a way our civilization runs off batteries.
Over billions of years the sunlight has been captured by stuff like this.
Then it's decayed away.
And in places like this, on the San Andreas Fault, the geological conditions are just right to cook this into oil that we can then pump out of the ground and burn and take that condensed sunlight and use it to power our civilization.
The energy from fossil fuels like coal, gas and the oil here in California have provided the power that built the modern world.
All of it the result of biology and chemistry made possible thanks to the great fusion reactor in the sky.
We thought we'd got lucky.
We'd found a seemingly endless supply of energy.
Here in the heart of oil country, I hooked up with physicist Rich Muller to chew over our dependence on the black stuff.
I love this.
What is our love affair with this substance, oil? Well, you know, I don't think of it so much as a love affair as a marriage.
And a somewhat unhappy marriage.
And we seek a divorce but the divorce is going to be expensive.
It really is a very remarkable substance.
It has enormous energy, enormous energy.
So much more than even TNT or dynamite.
It doesn't leave behind any residue.
Unlike coal, you don't have to clear the ashes out of your car.
All it does it is spew off this, what we used to call harmless gas, carbon dioxide, into the atmosphere.
In terms of energy, it's got more energy than TNT and natural gas.
More energy than these shotgun shells by a factor of almost a thousand.
The incredible energy density of oil is part of the reason why fusion is not yet here.
It's not simply that making the star is too difficult.
It's also that we haven't had to because the sun has given us the black gold.
It's such a wonderful thing.
Only problem is one, we're short of it.
And so it leads to war in the Mid-East.
And the second problem is, it does put out carbon dioxide and that very likely leads to global warming.
GUNSHO This is my new sport, man.
I like this.
Most of us on this planet, as we sit in our air-conditioned hotel rooms or at home watching TV, are still burning fossil fuels.
As a result, the carbon dioxide we are releasing continues to warm the planet.
Quite how this will change our world, and what this means for our civilisation, no one yet knows.
But what's strange is even though we do know our demand for energy is unbalancing the climate, the world cannot agree on how our species should power the homes, factories and farms of the future.
In search of an answer I've come to San Francisco, to the headquarters of a wind power research company, to meet its chief engineer.
I met Saul Griffith about a year ago, and I wanted to talk to him in this film because he's one of the few people I've met that takes the emotion out of the energy debate.
He just speaks in raw facts and figures.
And he's got an office in a control tower on a disused military base which is Here we are on this finite little bowl that's spinning through the universe.
There is a limit to how much power per square metre we can get.
We shouldn't be afraid of that limit, but we should certainly try to operate within it.
Let's as quickly as possible get the debate about energy away from emotional and qualitative and polar bear issues, and to a very rational, "what do we have to do, how do we get this done?" Saul's response was to begin at home.
He wanted to understand exactly how much energy he uses.
I'm a bicycle commuter, I use public transport, I run a wind energy company.
I should be a good human, right? But I didn't actually know, numerically, if I was good.
So I counted up all the energy my lifestyle uses.
I can tell you the amount of power it takes to have the New York Times delivered, how much power it takes to have a hot shower.
I know how much power I use flying around the place to talk to people like you.
I know how much power I use driving.
And I was a little shocked.
I actually use more than the average American.
So I am right now a hypocrite.
Here I am talking to you about all of this, but I'm using way more than the average US person.
That means that this halo of light behind me you see is not actually genius.
That's the 300 light bulbs that are burning constantly 24 hours a day, seven days a week.
That's how much power my lifestyle uses.
The average American uses 11.
4 kilowatts.
The global average is 2.
2 kilowatts.
Which means the world's total energy consumption is currently around 13 terawatts, or 13 million million watts.
To understand the scale of the problem, I posed a question to Saul.
What would it take to share the world's energy equally, and give all six billion of us five kilowatts each? A global total of 30 terawatts.
And let's see if we can achieve this, without fossil fuels, by 2035.
Let's shoot for this morally pleasing level.
This one.
We'll call this the Brian Agenda.
Well, yeah, because the Brian Agenda is to allow everybody on the Earth to live a lifestyle approximately like mine.
'In the west, we'd have to get used to using a lot less.
'But in the developing world, 'this extra energy could provide roads and schools and hospitals, 'everything we take for granted.
' So let's go with that.
It's hugely optimistic, but let's do it.
Let's go to five kilowatts.
'The next step is to figure out just how much clean energy 'that is for the entire world.
' Thirty terawatts of energy has to come from some new clean source or sources.
OK, 30 terawatts, 25 years.
I'm totally behind the Brian Agenda.
So, what are the implications of my eponymous plan to make the world a more equitable place? How about generating a sixth of our power, five terawatts, from conventional nuclear? So we need 5,000 nuclear reactors in 25 years.
That's two and a half full size nuclear reactors every week for the next 25 years.
Every three minutes you need to install a full size three megawatt wind turbine.
That's gonna be a couple of percent of the land area of the world that has wind turbines on it.
Solar at 10 terawatts, 250 square metres of solar cell every second - second after second after second after second for the next 25 years.
Biofuels, two terawatts.
This one looks a little scary.
That's something like four Olympic swimming pools full of genetically engineered bacteria, every second for the next 25 years.
And so on.
It's becoming clear that freeing ourselves of our fossil fuel addiction, let alone creating a more equitable world, is gonna require a massive global effort.
And we haven't even factored in the inevitable population growth.
So, look, this is possible to realise the Brian Agenda.
But it's a pretty radical programme.
This is like the re-tooling of manufacture for World War II, except Britain, Germany, Japan and America are playing on the same team.
And every week that passes by, when the world fails to build these alternative sources, means Saul's numbers just keep on getting bigger.
Could fusion power help? Unfortunately, right now for nuclear fusion, it's a question mark.
We don't know whether it works.
But the sensible thing would be to increase investment? Certainly if we nail fusion, that looks like the Get Out Of Jail Free card for humanity.
The aspiration to raise everybody up to a minimum standard of energy use, that is comparable with the energy use in the west, is not beyond the realms of possibility.
But a global consensus that we have to stop our destructive use of fossil fuels, is emerging.
What I'm not clear about is whether fusion is probably so far away that it won't have an impact on the first phase of the energy crisis, the phase we're in now.
So do we need to focus our investment efforts on building more efficient power stations, building solar and wind? Or, if we are convinced that fusion will work and the technological difficulties can be overcome on a very short timescale, then do we really go for it? Do we say we're gonna spend 10 or 100 times more R&D money, worldwide, on fusion now? I believe we must at least try as hard as we possibly can.
After all, we have already built a star, but for wholly different ends.
During World War II, a generation of the finest scientific and engineering minds were brought together in the New Mexico desert to work on the top secret Manhattan Project.
This is it, the place where the nuclear age began, the Trinity site, where the world's first nuclear bomb was exploded, July 16th 1945.
It's where the power of the nucleus was unlocked.
In just five years, they'd learned how to access the power of the nucleus by splitting nuclei apart.
They created a fission bomb.
They soon realised that they could release even more energy if they could fuse the nuclei and the fuel together.
Thing is, the fuel is positively charged.
And that means that as it comes closer together, it repels away.
What you're fighting is electro-magnetism.
But if the nuclei can be brought close enough together, against the repulsive electro-magnetic force, another force of nature, the strong nuclear force, will take over and bind the nuclei together.
So what you need to do is get these things moving fast enough that they get close enough for the strong nuclear force to kick in, short range, to lock them together.
Now, getting things moving fast is another way of saying you need to make them hot.
That's what temperature is, the measure of the speed of the fuel.
And the bomb builders had just the tool.
They would use the incredible temperatures and densities of a fission bomb to overcome the electromagnetic force and achieve fusion.
NEWSREEL MUSIC ORIGINAL ANNOUNCER: This is the first full scale test of a hydrogen device.
If the reaction goes, we're in the thermo-nuclear era! Just eight years after entering the nuclear age at Trinity, they were at the brink of lighting the first ever star on Earth.
' SITE PA: Now 30 seconds to zero time.
Ivy Mike, as the test was known, was the first full-scale attempt to detonate a fusion or hydrogen bomb.
One of the scientists who witnessed the birth of the nuclear age is Sterling Colgate.
We can simulate what goes on in a star.
In It isn't quite the laboratory, but at the test range, or some exquisitely beautiful atoll that we blow all to shit, if you don't mind the word.
Cos it's just ghastly what all of that did! And it's a lesson for the whole world.
Never, never, never let that happen again.
Five, four, three, two, one, zero! They had unleashed the most powerful force in nature.
This happens in the stars, it happens in our sun.
If it didn't, we wouldn't be here.
And so you can't turn the clock back.
You can't deny the physics.
It's there.
What we have to do is deny the use of a fusion bomb, a hydrogen bomb as it's called, in any anger whatsoever.
We absolutely have to make a massive commitment as a culture that this can never, never happen.
However we also need to take that knowledge and use it to generate power.
And make the power that we need to go on.
Future lab is completely gone.
Nothing there but water and what appears to be a deep crater.
Whatever you think about the power you can extract from the atomic nucleus, the simple fact, the scientific fact is, there is no greater power source in the universe.
It's the power source that powers the sun, it's the power source that powers the stars and it can be the power source that powers our civilisation.
What's needed is a Manhattan Project type effort to unlock the immense energy store of the atomic nucleus.
But this time for peaceful purposes.
Today, fusion scientists continue to face the same challenge.
They must overcome the electromagnetic force by creating incredibly high temperatures and pressures, but in a much more controlled way.
Currently, the world spends only £1 billion a year on the problem.
In the UK, we spent more money on ringtones last year than we contributed to the global fusion efforts.
You've got to ask yourself whether our civilization has got its priorities right.
Much of fusion funding still goes into bomb research.
But these days, the demolition of South Pacific islands is out of fashion.
Instead, the generals hire the world's most powerful bomb simulator.
Well, welcome, Brian.
This is the Z Machine.
Located on a high security base just outside Albuquerque, the Z Machine, as it's known, is run by John Porter.
So, this is the largest pulse power device in the world.
It's also the largest X-ray generator in the world.
So in about an hour we're going to discharge about 26 million amps through a little thimble-sized cylinder of wires.
This is, you know, 100 times bigger than the instantaneous power consumption of the United States, at least.
So, again, just phenomenal amounts.
But for very short periods of time.
With all this power at its disposal, the Z Machine is able to recreate the conditions inside an H bomb.
And so at this point, the conductors are inside a vacuum.
And then they're converging all to the axis and about, I dunno, 10 feet down there is where all the current gets concentrated in the thin wires.
Nearby, John shows me a target that will sit at the centre of the machine.
So the 26 million amps is flowing right along there.
And then you can barely see the array of wires.
There's probably like 300 wires here.
- They look like a spider's web.
- Exactly.
- Absolutely tiny.
When it fires, these wires are rapidly vaporised.
And the strong magnetic field generated by the enormous electric currents force the wire remnants to implode.
This is known as a Z-pinch.
And it's this that creates the conditions for nuclear fusion to occur.
The diagnosticians are back down from re-arming and we're gonna continue with our check list.
The radiation generated by this machine is extreme, and it can, in certain places, create lethal doses of radiation.
- So it's not a good idea to be stood here when you do that? - That's right! - So it's about to get dangerous, so we'd better take off! - Right.
And we've got red flashing lights, - all the signs that it's better to leave.
- Yeah.
Very exciting.
So we do about one shot a day.
So this has already been locked up.
I'll take you to the control room.
The X-rays are so intense that people and video cameras are only safe inside the specially-shielded control room.
- You guys ready? - We're ready for you to arm.
- OK, we're still armed.
Attention building 983, Z is preparing to fire.
We are starting ZBL countdown.
We are counting, T-minus 135.
We are charging.
They're gonna take it up to 82,000 volts.
We are charging the MTGs.
When it fires, this vast brute of a machine is powerful enough to create a minor Earthquake that's felt across the entire site.
Charge complete, arming to fire.
T-zero - DISTANT BOOM - Trigger! - Whoa! Only one image of the blast has ever been captured.
This is that image.
It's called a flash-over, the result of the ferocious electromagnetic pulse as lightning dances around the metals in the room.
Thanks, John.
Did you guys trigger? Cool.
That was it, it's a success.
I felt the ground move.
I think you did too, Brian? Yeah.
And heard it out there, actually! All right, let's go look and see what's left after the shot.
So this was all fairly pristine, at one point, stainless steel.
It's quite remarkable.
It's almost like the Well, it is the conditions in an atomic bomb, isn't it? Well, that's the reason these facilities were first created.
- So, that's why it looks like it's been in a nuclear war? - Exactly! - Cos it has! - Right.
A relic of the Cold War, the Z Machine is being re-invented.
It turns out that this bomb simulator could perhaps be turned into a peaceful source of fusion energy.
It costs a few tens of thousands of dollars to machine.
All the parts we just blew up in a few billionths of a second.
The big hurdle is doing it a few times a second or a few times a minute, depending on the yields, to get enough power to be useful.
- Then you've got a power station.
- Exactly.
It's the last few feet, the stuff that gets blown up.
Coming up with new ideas on how to rapidly replace that.
Currently it takes at least a full working day to prepare the Z Machine for another shot.
But if they can learn how to replace all the hardware that gets destroyed quickly enough, in less than a minute, then it's possible that a machine similar to this could one day produce a steady stream of energy.
But it's a tall order.
We believe this technology that you're seeing here is the simplest, most elegant and efficient technology that one could imagine to create fusion.
But no one knows, you know, what's really possible.
Right? The Z Machine proves it is experimentally possible to light a star on Earth by initiating a controlled explosion around a fusion fuel.
So it does recreate the conditions that are present at the heart of a star.
It's also produced fusion.
But most of all it's simple.
That is the most impressive thing to me.
It was, or it is, in a way, 19th century technology.
And that's not to denigrate the machine at all.
It's a very simple idea.
And I suppose if you want to build a power station, if you really want technology you can produce on an industrial scale, then you want to do it in as simple a way as possible.
And that's because the scientists are facing perhaps the most difficult engineering challenge in history.
To produce a viable power plant, they must engineer machines that can not only create and withstand the violent conditions found in stars, but that are capable of creating hundreds of these exploding stars, every minute.
Only then will they be able to extract a steady supply of energy and create significant amounts of electricity for the grid.
No wonder fusion power is taking so long to come online, even though we've understood this process at the sub-atomic level for well over half a century.
This is how fusion works in the sun.
You start off with protons.
Nuclei of hydrogen.
And if those protons can get close enough together, so the strong nuclear force, short range force can lock them together, then one of those protons can turn into a neutron.
And two particles called the positron and neutrino come flying out.
And that makes an isotope of hydrogen, something called deuterium.
And about a 7,000th of the hydrogen in your water is actually deuterium.
So it's pretty common on Earth.
That process takes a long, long time.
In fact, for a single proton in the sun, then it would have to wait billions of years to get close enough to undergo that process.
So that's the blockage in fusion in the sun, if you like.
Once that's happened and the deuterium's formed, then everything goes very quickly.
Another proton can come and meet the deuterium and that turns the deuterium into helium-3.
And actually a photon particle of light comes flying out.
And then two of these helium-3s can stick together into helium-4, and a couple of protons come flying out.
So that's the process by which energy is released in the sun.
It's the process that allows the sun to shine.
On Earth though, we have an advantage.
We don't have to go through the lengthy process of making deuterium because the oceans are full of it.
A rich seam of energy that could supply the entire world for millions of years.
It's this tantalising promise of effectively unlimited energy that has inspired another approach designed to initiate fusion.
At the Lawrence Livermore National Laboratory in California, they're attempting to create a stream of exploding stars using nothing more than a light beam.
Wow! The governor yesterday, and me today! VIDEO NARRATOR: The National Ignition Facility will do what has never before been accomplished.
To create a self-sustained nuclear fusion reaction in a safe, controlled setting.
At the National Ignition Facility, or NIF, they've built the world's largest and most powerful laser.
Showing me around this enormous site is fusion scientist Eric Storm.
- Is that the laser? - Yeah, stop a second.
It looks like a factory.
The 500 trillion watt laser beam travels half a kilometre, guided by a series of lenses and mirrors, a pulse of light with a thousand times the instantaneous amount of energy in America's national grid.
This shows the actual size of one of these laser beams.
They all come from one single source and at the end get focused onto this fusion target.
TWO-WAY RADIO: We're trying to get hold of Sopado or Seranowski.
- You can see it is somewhat more impressive.
- It's incredible.
You know, this looks like a facility that creates stars.
It does, doesn't it? It looks like it does what it says it does.
These aluminium square tubes here, that's where the laser beams come in.
There are 96 beams on the top and 96 on the bottom.
There are focusing lenses that take these beams and focus them down to a human hair.
That would give you quite a suntan, wouldn't it? Yeah, you would?! I do not recommend it.
Let's go and look inside the chamber.
INDISTINCT VOICE ON RADIO - Right, you're looking inside the star chamber.
- Look at that.
INDISTINCT VOICE ON RADIO - The target will be sitting You can see the - It's moving in.
That's the one that will hold the target in the centre of the chamber.
- Which is the seed of the star.
- The seed of the star, absolutely.
BELL RINGS 'The man in charge of the most powerful laser on Earth 'is Ed Moses.
' I want to talk about the target because this is the First, how much energy do you get out of one of those targets? It's an interesting question.
This target is pretty small.
That little ball is where the fuel for this target is.
Cos this is where the challenge is, right? The design of this thing.
There's a lot of challenges.
You have to put the laser together, - you have to get all those lasers - You've done that, though.
- Yeah.
We have to get those 192 beams steered very precisely into this target.
The laser light is coming down and up on it in a very symmetrical fashion so we make a very uniform oven.
That little ball starts collapsing at a million miles an hour.
When it starts moving, the hydrodynamic forces on it are such that it could start ripping itself apart.
So you have to make it come together really nicely and smoothly till it's about the diameter of your hair.
When you do, you'll have temperatures of around 100 million degrees and pressures of around 100 billion atmospheres.
It'll be about a hundred times as dense as lead and that's when it will light up and this is not chemical burn.
This is nuclear burn, that's what's so interesting.
You get around 30 million times more energy per mass out of a nuclear burning device than a chemical burning device.
But no laser-powered fusion device has yet to achieve this.
So far, it's proved difficult to focus all the power onto the target at precisely the same time.
Only if this can be overcome will the fuel target be heated and condensed enough for fusion to occur.
This is the Holy Grail - the quest for ignition.
So you had this star that's about the diameter of a human hair for a billionth of a second.
Yeah, it's star power on Earth.
That's what we say.
If we can do it a few times a second then you get the kind of energy that comes out of a power plant.
NIF is not a power plant, but this vast experiment may be on the brink of igniting a star.
It is our future.
When is that future going to arrive? What would you say? I know it's difficult to speculate, but 10 years, 20 years, 50 years? I think from the point of view of proving fusion in this laboratory, our goal is to do that in the next two or three years.
Sometimes, people talk about fusion as being 50 years away.
Right now, I look at it as two or three years away.
By 2011, the world should know whether laser-powered fusion will achieve ignition.
Should they fail, then all humanity's hopes for fusion will shift to another group of scientists.
These researchers believe our future energy will come, not from a stream of short-lived mini stars, but from learning how to create and hold the very matter of the sun for days and months on end.
They too face a tremendous challenge for they seek to control the least well understood state of matter - plasma.
If you heat up any atoms or molecules, what happens very quickly is that the electrons around the nucleus start to boil off.
The temperature's too high for them to stick in orbit around the nucleus and that is the state of most of the universe, including the state of our nearby star, that incredibly hot ball of plasma - the sun.
Producing long-lived plasmas is the oldest line of fusion power research.
For 50 years, a small group of countries have run prototype fusion reactors in an attempt to extract energy from stable plasma.
The very latest country to join this club is South Korea.
Here we are - the National Fusion Research Centre.
Strange thing as well, it's in the middle of an industrial estate.
When you think of a nuclear reactor facility, you tend to think of it out in a field somewhere, but it's right in the middle of the city.
- Good morning, how are you? - Good to see you.
- OK, I'll show you the KSTAR.
- Thank you.
'KSTAR, like the jet reactor in Oxfordshire, 'is a type of fusion reactor called a tokamak.
' - It's a beautiful device.
- Ah-ha.
- It's clean.
'It was completed in late 2007 'and I've been invited to see the device before it begins operation later this year 'by its chief creator, Dr Lee.
' He used to be a vacuum engineer.
- Thank you.
- You can go.
'What makes KSTAR unique are the advanced super-conducting magnets 'that hold the plasma in place.
'They cool to minus 269 degrees.
'At this temperature, 'the magnets have no electrical resistance, 'which means KSTAR needs a lot less power to run than its predecessors.
' What's the thing you hope to learn with this machine? So far, all the tokamak fusion reactor runs for a very short period of time.
A few seconds.
So we, scientifically, we have proven fusion can be realisable.
- Yeah.
- But on the other hand, we have to make energy - so this machine has to run a long way, you know? - Mmm.
Eventually, nine months and ten months continuously.
So, you would contain the plasma? - Yeah.
- What, months at a time? Yes.
'KSTAR aims to show that plasma can be routinely created and held 'for long periods deep within the heart of the machine 'in the way needed for a commercial fusion power station.
' This is a very exciting moment, actually.
I never imagined I'd get to climb inside the reactor, which is unbelievable.
It's not easy access! How did he do that? HE LAUGHS Oof! This is brilliant, I've got to say.
Well, this is the inside of KSTAR.
When this is operating, where my head is, there will be a plasma, 10, 20 times hotter than the core of the sun.
And it works, basically, like a home microwave oven, except that six megawatts is the power consumption of 2,000 domestic houses.
So it's a remarkable place.
The temperature here, 20 times hotter than the centre of the sun.
Below my feet, where the magnets are, minus 269 degrees, which is something like the temperature, if you go outside the Earth's atmosphere, and outside, actually, to the most distant planets, incredibly cold.
And this is one of the best bits, in a way, it's the television camera.
And they've already had some success.
Just before my visit, they ran the machine for the first time.
It's not fusion yet, but an important step towards KSTAR's goal of holding 100,000 degree plasma for five minutes.
If they can achieve this, it will be a significant landmark on the road to fusion power.
Will you get net energy out of KSTAR? KSTAR will be kind of break even machine.
So, energy consumption to really support the whole system, and the energy out is almost, you know, one to one, like.
But an economical power plant, we are now considering, is about 30 to 50 times of this is necessary.
Means one watt comes in, and 30 to 50 comes out.
Then, we can really make it in the reasonable cost of electricity from the fusion device.
The South Koreans have built KSTAR as their contribution to an international project to build the biggest fusion reactor ever attempted, called ITER, which is about to begin construction in Southern France.
- Really, this is the start of the final phase of R&D towards fusion.
- I think so.
We have done 50 years of R&D in fusion, fusing lots of machines, many places.
- Now, this is endgame.
- Yes.
So, now, put together all the knowledge of these 50 years and now, merging into this, KSTAR, ITER, and finally, commercialisation.
This machine, having seen it, means more to me than I thought it would because I really get the sense that if this doesn't work, then, we're in, literally, real trouble.
Hopefully, it's all engineering, and it's all practice.
It's not simple because it will take decades.
But it's not a fundamental issue, because if it were a fundamental issue, then this kind of fusion would drop out of the race, and we'd be left with one, with laser fusion.
And for me, if you think that fusion is the future of our civilisation, that's a big risk.
So, good luck, KSTAR.
If you'd asked me before I made this film - what are the greatest achievements in the history of humanity?, I would say, the moments when we overreach, the moments when we set foot on the moon, or took photographs of Saturn and Jupiter and distant planets.
Building a fusion power station that works and delivers electrons into the power grid of a city will be the next step in the evolution of our civilisation.
It's just about beyond our capabilities, technologically and scientifically, at the moment.
And that's surely the best place to be.
That's the place you want to stand, as a human being.
So, I would celebrate the fusion power station builders in a way that I wouldn't have done before we made this film.
So, when can we expect fusion power from the mains? All right.
My prediction.
I hate being a futurist.
This time tomorrow, where will we be? 2036, June.
That's when it COULD be done with an exerted effort.
I don't think it will happen until then.
This time tomorrow What will we know? There's a 50% chance of it working, 20 years after you seriously fund the science.
So, it's time for a commitment.
I'll leave the sun behind me And I'll watch the clouds as they sadly pass me by Seven miles below me I can see the world and it ain't so big at all This time tomorrow What will we see?