There are some great questions
that have intrigued and haunted us since the dawn of humanity.
The story of our search to answer those questions is the story of science.
Of all human endeavours, science has had the greatest impact on our lives,
on how we see the world, on how we see ourselves.
Its ideas, its achievements, its results, are all around us.
So, how did we arrive at the modern world?
Well, that is more surprising and more human than you might think.
The history of science is often told as a series of eureka moments.
The ultimate triumph of the rational mind.
But the truth is that power and passion,
rivalry and sheer blind chance
have played equally significant parts.
In this series, I'll be offering a different view of how science happens.
'It's been shaped as much by what's outside the laboratory as inside.'
Whoa!
This is the story of how history made science,
and science made history,
and how the ideas that were generated changed our world.
It is a tale of...
..and
This time, one of the oldest questions we've asked:
These days, you have to drive a long way to go and see the night sky the way that our ancestors did.
One of science's great achievements was to create artificial light.
But unfortunately it does tend to blot out the beauty of the cosmos.
It's very peaceful and quiet here, which is rather surprising
because you and I are actually on a giant rock,
which is spinning through empty space at at least 1,000 miles an hour.
And with our companion, the moon,
we are also hurtling round the sun
at a terrifying 67,000 miles an hour.
And that's not all,
because we are part of a huge galaxy called the Milky Way, which consists of hundreds of billions of stars.
Out there, we have seen the birth and death of stars,
heard the whisper of creation.
We now realise our universe is a place of unimaginable strangeness.
It is so hard to understand that it's not surprising that, for most of history,
there was a very different view of what is out there.
This is the story of how we came to know what we do know about this bizarre and dazzling universe.
For me, the story begins in Prague,
in the opening days of the 17th century,
a defining moment in the creation of modern science.
It was here that three critical factors came together.
Men with daring ideas.
Collectors of evidence.
And someone prepared to pay for it all.
Europe was in turmoil.
Forces of religious and political change were sweeping across the continent.
These were violent and dangerous times.
But, out of all this tumult would emerge a new vision of the cosmos.
It all started when a couple of the age's more unusual thinkers
came to work at the court of the Holy Roman Emperor, Rudolph II.
In those days, Prague was a major centre of power and culture.
The Emperor Rudolph was hungry for new discoveries.
New ideas to dazzle and impress his fellow rulers.
His enormous wealth and patronage drew to Prague one of the
brightest stars of the age, the astronomer Tycho Brahe,
an eccentric Danish nobleman.
Tycho was a wonderfully colourful character.
When he was a student, he lost a large chunk of his nose in a duel
and had it replaced with a metal one.
Legend has it he kept a dwarf under his table, and he believed that that dwarf was clairvoyant.
He also apparently kept an elk, which fell down the stairs when drunk, and died.
There is however one thing about Tycho which is absolutely certain - he was a passionate stargazer.
Science needs evidence, and Tycho was a new sort of data gatherer.
He built a vast observatory, and equipped it with the best instruments money could buy.
And so was his commitment, night after night for over 20 years.
He was putting together a unique body of evidence
that would in time reveal the secrets of how the planets move.
Right. So we've got the moon over there.
Now this is how you'd make an observation with Tycho's Quadrant.
It is of course pointing at the moon.
You take the sighting arm.
You sight it exactly upon the moon.
You would look through the upper slit across the upper part of that central brass peg... Yeah.
Then the lower slit through the lower peg,
so the upper and the lower cusps of the moon,
the points of the moon, were between them.
You've got it lined up, essentially.
Absolutely lined up.
OK. So I get that as 15 degrees...
and 40 minutes of arc. That sounds perfectly reasonable. OK.
And that is logged as the moon, on the 26th of May at just past ten o'clock. Just past ten o'clock.
So he would go on plotting these details throughout the night.
Yes. Not just the moon, the moon would set, but you'd do it for planets,
as things appropriately came in the sky, and build up these great observing logs of raw data.
And out of that, of course, is what the heart of science is.
Tycho starts his tradition of science, not just being about information and theories, about data.
Information and analysis from fresh observations.
Books of it, presumably? Absolutely.
Having seen you in action now, what I'd like to do now is look at a star, the pole star, the north star.
The pole star, which of course everything rotates around, the star over here.
What Tycho was doing represents something really important
in the emergence of science -
a commitment to cold, hard, obstinate facts.
I can see it now I'm lining it up with that and...
That is 51 degrees and 36 arc minutes.
Right, excellent. So that's my first star. It is indeed. Not bad at all.
Thank you. I've got 776 to go.
Congratulations! Thank you. THEY LAUGH
It's a shame that the craftsmen who built such beautiful instruments,
and men like Tycho who used them,
get so little credit.
Because the evidence that he gathered would, in time,
undermine a belief system that had dominated Western thought for over 2,000 years.
Many early civilisations developed sophisticated ideas about the heavens.
But the Western view was, above all, defined in ancient Greece.
You can get a sense of Greek cosmology if you come here.
This is the sacred site of Delphi.
Its famous oracle drew people from all over the Greek world.
This is the Temple of Apollo, and it's where you'd have come and often received extremely cryptic advice.
It is also where you would have found the Omphalos, a stone which
marked the centre of the world, and therefore for many Greeks, the centre of the cosmos.
Down the centuries, Greek philosophers argued long and hard
about the shape of the universe and what is out there
until, in the end, one particular view became dominant.
Around the fourth century BC, a number of Greeks developed a model of the universe in which the Earth
was stationary and everything else moved in giant, perfect circles around the stationary Earth.
The perfect circular orbits of the other planets
reflecting the perfection of the gods that had put them there.
It was simple, intuitive and, of course, it was wrong.
Yet it endured.
So why did this idea persist for so long?
Well, it's partly because it's comforting to be at the centre of things.
But also because the alternative made absolutely no sense.
If we really are on a rock hurtling through space,
then surely we would be constantly buffeted by huge winds.
So, commonsense said the Earth must be stationary with everything going round it.
But there was a problem with this idea, a pretty fundamental one.
A remarkable discovery, made just over a century ago,
gives us a striking insight into the Greek view of the cosmos.
It was the result of a freak storm.
Battered by strong winds, a group of sponge divers took shelter on the small Greek island of Antikythera.
When the storm finally subsided, one of the divers decided to explore the unfamiliar waters.
There were no sponges, but strewn across the seabed were the remains of an ancient shipwreck.
Its cargo 2,000 years old.
They also found a strange bronze mechanism, which would turn out to be one of the rarest and,
in its own way, most precious treasures ever recovered from the ancient world.
It is a beautifully engineered scientific instrument, with wheels and cogs carved from bronze.
Nothing like this would be made for another thousand years.
But its exact purpose has long been a puzzle.
Michael Wright has spent more than 20 years attempting to
create a model of the original, and to understand its workings.
Hello. Hello. Nice to meet you. And this is the mechanism, is it?
This is the mechanism. Do you mind if I twiddle?
Of course, have a go. You won't break it.
So what's it doing when I turn this?
This is the representation of the sky as
people tended to think of it.
You can picture, if you like,
the Earth being at the centre of the dial,
and the planets and the sun and moon going round us.
That's the moon there. That's the moon.
And as the moon goes round, that's presumably what, full moon?
That's full moon because it's opposite the sun pointer.
What impresses me is, so somebody designed this well over 2,000 years ago. Yes.
Built it well over 2,000 years ago.
Of course, the bit you're looking at here is my restoration.
So, I don't guarantee the original was exactly like this, but I do say
with some confidence it was along these lines.
That is very clever!
But what this mechanism illustrates is how the Greeks wrestled with a tricky astronomical problem.
One that comes about if you think that the Earth is at the centre of the universe.
It's this.
The planets sometimes appear to move backwards in the night sky.
It's a problem that the Greeks recognised and agonised over.
Most of the time, they're going forwards,
which is sort of what I would expect, some of them going fast.
Ooh and that one's... Which one's that? Oh, that's Mars. Now we see it's stopped.
And there it goes backwards.
All the planets have these phases of going backwards. Right.
But Mars has a particularly bold one.
In general, you see them moving a little further east every night.
But there come times with each of the planets when they seem to stop
amongst the stars and go westward, for a, a period of days.
And then they stop again and go back eastward.
And this instrument replicates that behaviour.
This complexity didn't make the Greeks question their perfect circles.
Instead, they added more, a lot more - well over 50.
This tangle of circles moving upon circles explained how the planets
appeared to move backwards,
and preserved the belief in an Earth-centred universe.
The person who made this knew the latest astronomy,
he knew how to combine circular motions to get something like the true motion of the planets.
This view of the cosmos was one of the most enduring beliefs in human history.
It took root in the Arab world after the collapse of Rome.
And it was adopted by the Catholic Church in Europe.
It was so deeply embedded in European thought that it would take a radical shift to dislodge it,
and that was brought about by a great force of history.
The Reformation.
It began as a revolt against abuses by the Catholic Church.
And ended splitting Western Europe into two, Catholic and Protestant.
The new Protestant movement stressed the role of the individual outside the authority of the Church.
The Reformation created two conflicting views about
the route to personal salvation, about how you got to heaven.
If there could be doubt about such a fundamental question,
then perhaps there were also doubts about other ancient truths.
The Reformation created an intellectual climate
in which it became possible to question authority.
And, critically for the question, what is out there, the wars and violence that
followed the Reformation brought a rather special refugee to Prague.
Arriving to join Tycho the stargazer was an impoverished German mathematician, Johannes Kepler.
When Johannes Kepler arrived here in Prague in 1600, he was in dire straits.
His two young children had recently died, and he was in desperate need of a job.
When he arrived here, there was no procession, there was no imperial greeting.
I am reasonably sure that amongst his possessions however he would have had one of these horoscopes.
Ironically enough, a man who would be greeted as one of the greats of science practised astrology.
Kepler had come to Prague to work for Tycho.
But, soon after he arrived, Tycho died.
While the court mourned, Kepler purloined Tycho's vast collection of star data.
Kepler was now the court mathematician AND Rudolph's main astrologer.
To us, this might seem an odd combination of roles.
But back then, great rulers often had an astrologer, someone like Johannes Kepler,
to cast their horoscopes to peer into the future.
Astrology was all about predicting where and how the planets would move.
It depended on accurate star charts and good mathematics.
We still use astrological language when we talk about lunatics,
people who've been driven mad by "lunar", the moon.
Or disasters, terrible things that happen to us because of "astra", the stars.
But the effects of astrology are more profound than that.
It is precisely because people like Rudolph believed in it
that they were prepared to pay for detailed studies of the stars.
And these studies would prove vital when it came to developing a new vision of the cosmos.
In Prague, there was now a powerful alignment of forces.
The wealth and patronage of the Emperor Rudolph had brought together in one place
star data gathered by Tycho Brahe,
and a man with a mathematical ability to use it, Johannes Kepler,
alongside the intellectual turmoil unleashed by the Reformation.
All these forces coming together help explain why a new vision of the universe finally emerged here
in Prague at the beginning of the 17th century.
A model of the universe which placed not the Earth but the sun at the centre of everything.
Now, this was not a new idea.
It had been debated by Greek, Indian and Arab astronomers,
and rediscovered by Nicholas Copernicus,
a Polish cleric who was trying to tidy up the tangle of Greek circles.
Copernicus is often hailed as the man who changed our vision of the universe forever.
But his system was actually nightmarishly confusing.
He had planets whizzing round an imaginary point somewhere near the sun.
It was as complicated as the Greek model.
Copernicus died before Kepler was born, and the world had not been persuaded by his arguments.
But they had got Kepler thinking.
Kepler was convinced that the sun, the symbol of God, produces a force which drives the planets round it.
He was also convinced that only a sun-centred cosmos
could possibly account for the bizarre movement of the planets.
So, using Tycho's data, he set himself a challenge -
explain the movement of Mars, the planet with the oddest orbit of them all.
This is the confusion he was struggling with.
But he thought the ancient problem with Mars could be solved.
He believed he could explain this movement by having the Earth
and Mars travel in circular orbits around the sun.
Armed with Tycho's data, he set out to prove it mathematically.
It was unbelievably tedious work.
Hundreds and hundreds of pages of calculations,
which took him more than five years.
As he later wrote, "If thou, dear reader, are bored with these
"wearisome calculations, take pity on me who did it 70 times."
Kepler tried everything. He varied the speed of the planets,
he shifted the positions of the orbits,
but whatever he did he couldn't make circular orbits match Tycho's observations.
So he did something which, for a man of his time, was daring.
He dropped the enduring belief in divine circles, and tried other shapes,
until finally he found one -
an ellipse.
At last he had created a model of the cosmos that matched the evidence.
Kepler had demolished an edifice that had stood for more than 2,000 years,
and replaced it with his first law of planetary motion - all planets travel in ellipses around the sun.
You might have hoped that when Kepler published, the whole mad structure of the Greeks
would come tumbling down. Well, it didn't.
Many astronomers complained that he had brought physics into astronomy.
Others simply ignored him.
It wasn't until long after his death that his work was finally appreciated.
As many have discovered, being right is often not enough.
To get this new vision of the heavens noticed would require a very different set of events.
Astronomy would have to go tabloid.
'The story of what's out there now moves south.'
Renaissance Italy was awash with money from trade.
'The courts of Florence and Venice became magnets for those with talent and ambition.'
Renaissance Italy was the perfect place for a man on the make, a man like Galileo Galilei.
Now, he had aspirations to greatness, but at the time,
he was a middle-aged professor of mathematics
with three illegitimate children and few prospects.
Yet, within a year, he would enjoy a spectacular rise,
followed by an even more spectacular fall.
It begins with the unexpected arrival of a stranger.
In July 1609, word reached Galileo that a stranger had arrived in Venice,
trying to patent a wonderful new device called the Dutch spyglass,
which could make distant objects seem closer.
Now, if ever there was a city where such an instrument would generate excitement, it was Venice.
Venice is reliant on the sea, which makes it vulnerable to attack from the sea, which is why any device
that would give you advance warning of approaching enemy ships would clearly be of enormous value.
Galileo recognised the potential of the spyglass, but he also recognised
that if he was going to make any money out of it,
he was going to have to act incredibly fast.
OK, let's go.
Galileo had to get a fully working spyglass to the Doge of Venice before the stranger did.
'That meant he had to design and build one from scratch.
'Clues to how he did this come from a later shopping trip.'
On his shopping list, which, extraordinarily enough, still exists,
he had written, "Chickpeas and slippers for my son."
But he's also written down, "Glass, artillery balls and an organ pipe,"
and this is what you need if you are going to build a Dutch spyglass,
a device later renamed the telescope.
The best place to buy glass was the island of Murano, just across the lagoon.
'Here, a group of craftsmen had a skill so precious, they were barred from leaving Venice.'
That skill was the ability to make glass of crystal-like purity.
Perfect!
Wonderful!
Whoo!
We have a new glass-blowing master!
That was fun, thank you.
He smashes it up!
The glass was known as Cristallo.
It was bought by the aristocrats of Europe to adorn their tables.
It was the first really clear, colourless glass ever produced,
and it was probably this glass that allowed Galileo to build a telescope of stunning optical quality.
400 years ago, glassmakers started with a bottle,
and then opened it up into a sheet.
'The first stage to making a telescope lens.'
I've got glass from Murano, and I've got an artillery ball.
And I'm off to meet a lens grinder who apparently can use this to turn this into a telescope lens.
Buongiorno. Ah, buongiorno, Michael.
Hello. Have that one. Ah, va bene!
'In the autumn of 1609, Galileo himself began to grind and polish lenses.'
HE SPEAKS ITALIAN Ah, OK.
'By trying out different lenses, made with different sized artillery balls, he was able
'to produce magnifications of six and then 20 times.'
It might seem surprising that a mathematician like Galileo would want to get his hands dirty in
this way. But it's part of the important emerging trend in the 16th and 17th century.
People were no longer satisfied just to intellectualise,
they were making instruments and they were testing them out.
The fact that Galileo, a professor of mathematics, was grinding his own lenses, is of real significance.
This joining of the skills of scholars and craftsmen
was key to the emerging power of European science.
Galileo now took his new lenses, and through a process of trial and error,
worked out what the ideal distance was between them
to get maximum magnification along with maximum sharpness.
He then packaged them together into a new spyglass.
Now, what was truly impressive is that it had only been a few weeks
since he'd first heard of the Dutch spyglass, and yet he produced something which was far superior.
He now got together some influential Venetians, took them up the tower,
and pointed his new spyglass out at sea.
Its value was not lost on the Venetians.
You could now see ships two hours sooner than with the naked eye.
Galileo's climb to fame and fortune had begun.
'And then, fatefully, he lifted his telescope to the heavens.'
His telescope now uncovered dramatic new evidence about the cosmos.
'Evidence that would bring the idea of a sun-centred universe to the fore.
'I'm going to see the night skies as he would have done 400 years ago.'
Francesco, it has to be. Who else in the middle of the night?
Hello, Michael. Michael Mosley.
I have my Galileo telescope, which magnifies about sixfold.
I'm guessing yours does a bit more.
This one does 20, 20 times.
So this is optically identical, pretty much, to what Galileo had to deal with. That's right. Yeah.
Because the lenses have been analysed and studied and
reproduced with the same properties as the ones that Galileo used.
Can I have a look? Yes. I haven't really properly looked through something like this before.
Shall I start with that one there? Right.
Ah! Gorgeous!
This is what Galileo's lenses were able to show of the surface of the moon.
Night after night, he observed its phases.
His drawings are not just detailed, they are beautiful.
For me, it's basically, there's a lot of shimmer going on and it sort of pops in and out of focus.
I'm absolutely amazed that Galileo could draw the images at that level of accuracy.
I mean, really phenomenal.
This was how Galileo saw Jupiter.
No-one had seen these bright objects either side of it before.
They are moons, circling the planet.
And if there are moons circling a planet which is not the Earth...
did that perhaps suggest that the Earth was not really the centre of everything?
I must admit, having seen this, I have enormous, enormous respect for Galileo now.
I always saw him as a bit of a chancer, to be honest, but having seen what he did with a machine
with these limitations, it makes you think, wow!
He now took full advantage of another Renaissance invention, the printing press.
He put his findings together into this book, The Starry Messenger.
Unusually for an astronomical book of its time, it is well written,
it has lovely pictures and very little maths.
In fact, it soon became a 17th century bestseller.
'The book made him famous, and that encouraged him
'to do what he loved best, courting controversy and attention.
'Galileo had become convinced that the sun was at the centre of the cosmos.
'Now he began to promote that idea amongst influential people.'
His timing was terrible.
The Reformation had challenged the power of the Catholic Church.
Many within the Church now wanted to re-assert control.
A fight with Galileo suited them.
And then, in 1632, it all went terribly wrong for Galileo.
He published a book that destroyed his life.
The book enraged the Pope, and remained on the index of prohibited books for more than 200 years.
It's called The Dialogue.
He had been given permission to write this book, on condition it was balanced.
The book is presented as a series of discussions about the cosmos.
One side arguing for a stationary Earth at the centre,
the other favouring the sun.
But despite what he'd promised, Galileo clearly came down on the side of the sun at the centre.
But worst of all, what he was really saying is there are truths which go beyond the realms of religion,
or, as he once put it, "The Bible teaches us how to go to heaven, not how the heavens go."
Make no mistake, this was a huge challenge to the Church.
Galileo was saying that science can discover truths about nature
using its own methods of investigation.
And so, in 1633, he was brought to Rome to stand trial before the Inquisition.
The story of Galileo is often told as scientific hero
takes on reactionary Church over the question of a sun-centred universe.
But it wasn't really like that.
The trial of Galileo was actually about authority, who owns the truth about the heavens.
He was tried and found guilty.
The sentence broke him. Old, ill, in pain, he was condemned to life imprisonment,
and he spent much of it here at his villa in Arcetri, in the foothills above Florence.
Ironically, the banning of The Dialogue ensured that the book was widely read
in other countries, as people scrambled to get hold of a copy
and discover what all the fuss was about.
It was a moment of human reckoning.
We no longer sat at the centre of the universe,
just on another planet circling the sun.
The attempts to gag Galileo were utterly futile.
Within a generation, the educated classes throughout Europe had accepted that the sun and not
the Earth is at the centre of the solar system.
It happened, not in a single moment of genius, but as a result of a series of connections.
The patronage of the princely courts of the Renaissance.
A combination of different talents -
Tycho Brahe, Johannes Kepler, and Galileo Galilei.
Technological innovation,
raw data from telescopes,
and the power of the printing press to spread the new knowledge.
When you think about it, it is astonishing that nearly a century
separates Copernicus first publishing his book claiming that the Earth goes round the sun,
and Galileo's trial, after which, the idea finally gets widespread acceptance.
And when you look at it in that light, you realise that this claim, you get these violent
upheavals in intellectual thought which change everything overnight, well, that claim is clearly myth.
It is largely created by the comfort and distance of hindsight.
So, no sudden revolution, then.
As so often in science, what happened is that people who hold the old views slowly die off,
and a new generation comes in that sees things differently.
There was now a new force driving interest in the heavens - global trade.
Economic power in Europe was shifting away from the Mediterranean countries,
towards the Atlantic nations, like Spain, Portugal and England.
As new trade routes opened up, ships' captains needed better star maps to steer by.
Governments funded newer and better telescopes.
Astronomical evidence poured in.
New questions were being asked.
Why did the Earth and the planets move in giant ellipses?
And what was it that held the cosmos together?
One of the cargoes those ships brought to Europe was coffee.
'Coffee led to coffee shops, places where traders, ships' captains and assorted thinkers met,
'and fuelled up on caffeine.
'They became known as penny universities.'
Thank you very much.
Learned gentlemen would come to coffee shops to debate the central burning questions of the day.
And one of the key questions was, what is it that keeps the planets in their place?
Well, in 1684, this led to a bet.
At stake was two pounds, about a week's salary, but this would turn out
to be one of the most significant wagers ever made.
To win the bet, what they had to do was to prove that the elliptical path that planets take around
the sun, which Kepler described, obey a simple mathematical rule.
Now, smart though they were, they soon realised they were going to need help.
'One of the men who'd taken the bet, the astronomer Edmund Halley, set off in search of help,
'to Cambridge, to find the Lucasian professor of mathematics, a certain Isaac Newton.'
Halley manages to track Newton down, and he tells him about the bet.
Then Newton, to Halley's complete amazement, says,
"Actually, I've solved that problem, I've done the calculations, and they're here somewhere."
And he sort of rummages around amongst these papers.
But he can't find them. So he says to Halley, "I'll send them on to you."
The important thing about this visit is it seems to have triggered something in Newton's brain.
The memory of a time 20 years earlier.
A time when Newton returned to his family farm to escape an outbreak of the plague.
It was certainly safer, but I'm not sure how pleased he was to be back.
As a young man, he'd threatened to burn the house down with his mother and stepfather in it.
Described as artificial, unkind, arrogant, he was also
one of the most brilliant minds of his or any other generation.
'There are few more famous legends in the whole history of science
'than that of Newton in the orchard.
'That moment of genius when the young Isaac Newton first worked out a comprehensive theory of gravity.'
It's one of the great eureka moment stories.
Newton's in the orchard when he sees the apple fall.
The falling apple is said to have triggered a cascade of thoughts in Newton's mind.
Why is it apples always fall down?
Why doesn't it sometimes go sideways, or even upwards?
And if there is a force that is pulling it down, could it be that
same force is holding the moon in its rotation around the Earth?
And in that moment, the theory of gravitation is born.
Except the story's almost certainly made up.
Newton only started telling that story when he was an old man, and he possibly did it
because he wanted to ensure that he and he alone got full credit for coming up with a theory of gravity.
What is certain is that if he had a moment of divine inspiration
in this orchard, he did nothing with it for nearly 20 years.
It seems it was Halley's visit that prompted Newton to really develop his ideas.
He would express his thinking about gravity in a famous thought experiment.
He imagined a cannon on top of a high mountain.
He thought, if the ball leaves a cannon slowly, gravity would pull it to Earth.
If the ball is fired too quickly,
it would disappear into space.
But if the speed is just right,
then the force of gravity would hold the ball in orbit round the Earth, just like the moon.
An orbit that follows a simple mathematical law.
His monumental work, explaining that gravity held the universe together, was published in 1687.
This is Principia by Newton, and it is beautiful.
I have never held this book before, and I can feel
a little shiver going up my spine, because this is the book
which really did transform the world and in fact would go on to dominate science for the next 200 years.
This was when the new vision of the universe truly came together,
built on Tycho's observations,
Kepler's elliptical orbits,
and Galileo's discoveries.
Now Newton outlined universal laws of motion that explained how the planets moved.
Newton was clearly a scientific giant, but he was also much more than that.
The way that he had shown that a few universal laws could explain so much of the physical world inspired other
intellectuals to look for universal laws that could explain human behaviour, politics, even history.
Newton became a hero to revolutionaries who dreamt of utopian societies founded on reason.
In America, politicians were inspired by Newton's laws of action and reaction
when they created their famous political system of checks and balances.
And in religion, an ordered universe was taken to demonstrate
the existence of a God of infinite power.
And astronomy?
There was now a new stable model of the universe, a clockwork universe,
governed by a few simple laws.
And that's how things stayed for the next 200 years.
The question of what is out there has always followed the money.
And in the early 20th century, it headed across the Atlantic
to California, where they were enjoying an oil rush.
Oil and railway barons, like Renaissance princes before them,
craved the sort of fame that astronomy could bring.
One philanthropist, who had made his money building
pipelines and selling hardware, helped finance the next radical shift in our view of the cosmos.
John D Hooker was persuaded to donate 45,000 towards building
the largest telescope the world had ever seen.
And they dragged it up Mount Wilson, this mountain, which is just outside Los Angeles.
It is a fantastic structure.
'A hundred tons of pipework, hardware and glass floats on a bed of mercury,
'allowing it to compensate for the Earth's rotation.'
Isn't that magnificent?
Over 90 years old and still fully operational.
But for this gargantuan telescope to fulfil its true potential,
it would need a character who was also larger than life.
Edwin Hubble was an exceptionally colourful scientist.
After a spell at Oxford University,
he came home with a faux upper-class accent,
and worked in jodhpurs and high-topped riding boots.
He was also exceptionally fortunate to be hired to work with the new Hooker telescope.
Now, Hubble was a brilliant astronomer, and he had the world's largest telescope.
Now the thing is, even with a telescope this big, the human eye is just not good enough
to pick out the detail that was needed.
So there was a camera attached to the telescope.
And with it, Hubble photographed stars at the far reaches of the Milky Way,
at that time, the only known galaxy in the universe.
On the 6th October 1923, Hubble took a photograph
that must rank as one of the most significant photographs ever taken.
This photograph demonstrated for the first time just how vast the universe truly is.
Now, what you can see here is a black, swirly area, which is actually the Andromeda nebula.
But what got Hubble excited was a little black speck here,
which he's labelled as VAR, or variable star.
This was a huge discovery.
The pulsing of a variable star could be used to calculate its distance from Earth.
Hubble came to a startling conclusion.
His star, and the nebula in which it sat, were almost a million light years away,
far further than had been thought possible.
Now, Hubble realised that he could prove for the first time that the nebula was actually a galaxy,
and it sat way outside our own galaxy.
Suddenly, the human race, our world, our concerns, became cosmically insignificant.
We are just one small planet in a vast galaxy, that sits amongst billions of other galaxies.
The implications of what they had found were disturbing.
The universe was vast, possibly limitless.
But what they did next was even more shocking.
They linked this giant telescope up with a device called a spectrograph,
and they pointed it once more at the skies.
They were hunting for objects which they now believed to be galaxies, and using the spectrograph,
they measured the speed at which those galaxies were either coming towards or away from us.
What they found was the vast majority of these galaxies
were actually receding, and some at quite astonishing speeds of well over a million miles an hour.
Now, the implication of this was obvious, the universe is expanding.
Now, this really blew out of the water the old way of thinking.
Gone forever was the old static, stable, Newtonian clockwork model.
It seems, now, we are actually living through a giant cosmic explosion.
It seems our universe had a beginning.
13 billion years ago.
This became known as the Big Bang.
Edwin Hubble never felt he achieved the recognition he craved
for his discovery of the vastness of the cosmos.
But floating high above the Earth is the ultimate tribute to this eccentric astronomer.
The Hubble space telescope.
400 years since Galileo ground his first lenses,
this is what we use to look at what's out there.
It can peer billions of light years across the universe, back in time towards the birth of everything.
Our journey to find out what's out there has been shaped by powerful forces and beliefs.
The Greek obsession with divine circles.
The courts of the Renaissance.
By religious upheaval.
Above all, by the marriage of two skills -
the making of instruments and the generating of ideas.
And it's still going on,
as we find new ways of looking ever deeper into our universe.
So, what is out there?
Well, rather a lot.
We've seen the birth of stars, in nurseries of gas and dust.
Evidence of super massive black holes.
Clues to dark energy that may make up most of our universe.
Some of these ideas are as strange and unsettling to us
as the Earth going round the sun was to contemporaries of Galileo.
But I think what this journey really boils down to is trust in evidence.
'Because no matter how strange the conclusions may seem,
'it's only by accepting evidence that we have come to understand
'not just the universe, but also our place here within it.'
Isaac Newton, in a moment of uncharacteristic modesty,
once said that he was just a child playing on the shores of a vast ocean of undiscovered truths.
But I think the contribution he and his fellow stargazers really made
was to open up our minds to what is going on, not just up in the heavens, but down here on Earth.
'Next time - delving deep to find beauty and order.
'What is the world made of?'
Subtitles by Red Bee Media Ltd
E-mail - subtitling@bbc.co.uk