Time How We Got to Now with Steven Johnson

Have you ever noticed how completely dependent we are

on knowing the exact time? I mean, we take time for granted now,

but just 150 years ago, it was all very different.

For instance, back then, America had hundreds of towns

each using its own different local time,

and 50 railroad companies each with its own time.

It was a total nightmare trying to take a train around the country.

I mean, you'd have to be a math major to figure out what time it is.

And you could forget about ever owning a watch,

unless you were incredibly wealthy!

Back in the mid-1800s,

handcrafted luxury watches were the only kind on the market.

So, who fixed these problems?

Well, it was a railway clerk and a cobbler's son.

These guys are classic examples

of the kind of people who actually made the modern world.

People you've probably never heard of.

These are hobbyists and garage inventors...

..maverick characters doing extraordinary things.

The thing about these pioneers is that they didn't just master time.

They also set in motion an amazing chain reaction of ideas.

Resulting in innovations that would go on to affect

every aspect of our lives.

From how we navigate...

to how we work.

Enabling sophisticated technology,

and time travel into the past.

I want to show how the link

between all these apparently unconnected worlds

starts with the heroes of time.

All my career, I've been fascinated

by ideas and innovation, from writing books

about the great British innovators of the Enlightenment

or the Industrial Revolution,

to my work with Silicon Valley start-ups,

and what I've learned about innovation

is that the experiences of the past

are still the best roadmap for our future.

And that's why I want to tell you the story of how we got to now.

Sounding, 758...

'If you want to completely mess with your sense of time,

'this is the place to come - the nuclear submarine USS Ashville.'

Steven, third wake-up, time to get up.

Most of us, when we wake up or go to sleep,

we're following the natural cues of the sun rising or setting,

but on a submarine, when you're out on the ocean,

underwater for months at a time,

you have none of those cues available to you.

So people living on a modern submarine are as far removed

from the natural rhythms of time as any human beings on the planet.

This submarine is about to leave port for the next month.

Up scope.

'The only view Lieutenant Commander Jason Deichler will have

'of the outside world is through this periscope.'

That's a really clear image but, gosh, it must be amazing

to go for like 30 days and that's your only glimpse of sunlight.

That's our only glimpse of topside.

That's our only chance to ever see the sunlight.

I feel like a... Can I just fulfil a lifelong fantasy here,

-if you don't mind?

-Absolutely.

Here we go, I'm going to do it. Dive! Dive!

KLAXON BLARES

'But the crew aren't just deprived of the sun.

'They've also got six hours taken out of their day.

'Because every day aboard the USS Ashville is sped up

'to the cycle of an 18-hour clock.'

'The crew gets six hours on watch,

'six hours on light duties and recreation,

'six hours of sleep, and then it begins all over again.'

'By completely detaching from sunlight,

'the crew's sense of time can be heavily manipulated.'

I have a lot of questions about this, it's fascinating, but why do you do it?

Well, we have limited amount of resources and men on board the ship

and it's our way to get through the day and maintain the amount of sleep

that you need and rest you need to stay on watch.

And so, not only are you guys breaking from the 24-hour day,

but everybody's on a different clock, right?

Somebody's night-time is somebody's daytime?

Absolutely, and that shifts continuously

because of the way the 18-hour clock rotates.

So when a man wakes up, all he knows is "I need to get on watch."

He's not as concerned if it's light or dark outside,

cos we don't get the chance to see the light or dark

as much as the people on the surface do.

Those strange surface-dwellers!

Yes, the surface-dwellers.

We just disrupt everything that has to do with the clock.

We kind of become masters of our own time, in a way.

Most of us would have a hard time living on an 18-hour day,

so far removed from the sun, but the truth is,

almost all of us today are living on artificial clocks

of one form or another.

How did we get so far out of sync with the natural rhythms of the sun?

That's a story that takes us back more than five centuries.

CHURCH BELL RINGS

For millennia, we'd rise with the sun and go to bed at dusk.

The very notion of time-keeping was all pretty relaxed.

I mean, you wouldn't want to set your watch

by this typical 14th-century mechanical clock in Tuscany,

which could lose or gain up to 30 minutes a day.

Back then, time-keeping was a comically imprecise pursuit.

I mean, a clock like this one would be corrected

with occasional readings of a sundial

or sometimes just looking up at the sky and making a ballpark guess.

Which meant that every clock in every town

was telling a different and irregular time.

But the thing is, no-one really cared back then because, 500 years ago,

the whole idea of split-second accuracy in timing

would have been as useful as a satellite dish.

Back then, meeting times were set by the movement of the sun

and time was measured by the daily tasks required to work the land.

For example,

if I wanted to arrange a meeting with someone in 15 minutes' time,

I might say something like, "I'll see you in the milking of a cow."

This was all rather vague and, as a result,

daily schedules were completely unregulated.

But our relationship to time was about to change, thanks to this guy -

Galileo.

A born rebel, he became a legend for proving that the sun,

not the Earth, was at the centre of our solar system.

But in 1583, he was just an unknown student who would discover something

that would forever change the way we travelled, traded and worked.

You ready? Hold it up, use all your strength. Perfect.

-Thank you so much.

-Sure, sure.

Of course, we had a bunch of professionally trained cameramen around,

but they asked me to do it.

Most people come to Pisa for its leaning tower.

Yeah, there? Oh, my God, it's really heavy.

But the origins of modern time as we know it

can be found close by, in the city's magnificent cathedral.

It's here that Galileo has an insight

that will revolutionise how we measure time.

The story goes that it's 1583,

Galileo is 19 years old, and he attends prayers here every day.

But one visit, he gets distracted

by something that most of us wouldn't even notice -

a swinging altar lamp.

Highly musical and sensitive to tempo,

he studies the rhythmic movement.

Galileo then uses his pulse as a metronome

to time the swing of the altar lamp, and he notices something unusual.

No matter how far or how short the lamp swings,

it takes an equal amount of time to swing back and forth.

This is what I love about Galileo.

I mean, he's a teenager,

and all the other kids are dutifully reciting the Lord's Prayer

and he's nerding out on the physics of the pendulum.

This is what's so critical

to Galileo's contribution in changing time - his rebellious nature.

Back then, a good scholar was supposed to simply quote

existing scientific knowledge, not investigate it.

But Galileo's more keyed in to the thrill of discovery than convention,

and he sets up an experiment which confirms his observations.

Galileo writes to a friend, "The marvellous property of the pendulum

"is that it makes all its vibrations, large or small, in equal times."

And it's that discovery, the idea of equal time,

that will become one of the foundations of modern life.

This gives Galileo the seed of an idea -

a hunch that a pendulum's an important tool for measurement.

So, what happens next? Well, nothing.

That's partly because Galileo is busy becoming a genius in physics,

mathematics and astronomy,

alienating his academic colleagues...

and struggling with money.

But this seed won't actually bear fruit for almost 60 years

because, right now, no-one actually needs an accurate clock.

And this is the interesting thing about great ideas -

just like plants, they often need the right set of conditions to flourish.

So this insight is just parked in a corner of Galileo's brain.

That is, until a new set of conditions come along

which, luckily for Galileo, are backed up by a whole heap of cash.

In 1598, King Philip III of Spain

grabs the attention of every scientist in Europe

by offering a life pension in ducats to anyone who can solve

the greatest scientific challenge of the age - a way to measure longitude.

Oh, boy!

Ships in Galileo's day were sailing blind over vast new distances

and frequently meeting with disaster.

For the New World to be conquered, something had to be done.

All right, so, what happens if I try and actually take the wheel?

Yeah, I'm happy to give you the wheel.

-I have no training whatsoever.

-No problem.

-Nothing can go wrong.

-Carry on.

-Thank you.

So, I'm piloting or skippering or something -

I don't even know what I'm doing with this sailboat -

but I've been given the instructions here to follow 060 on the compass,

which I'm kind of managing to do, although it's pretty hard.

But the bigger problem is I have no idea where I am.

So, what does any of this have to do with time?

It was maritime navigation

that would drive the advancement in our measurement of time.

On land, there's no need for clocks that are accurate to the second.

But at sea, in this age of discovery,

sailors are starting to realise that accurate measurement of time

is crucial to navigation,

which means that the need for accurate clocks

won't come from the calendar, it will come from the map.

Navigators can figure out their latitude -

how far north or south they are - by reading the sun.

But to figure out longitude and how far east or west they're going,

they need two things -

the local time on the ship,

and the exact time where they left port.

Using the difference between these two times,

they can calculate their exact position.

But with no accurate clock on board,

they soon end up completely lost.

I have to get us back on course here.

So this challenge, accompanied by a fat reward,

is looking good to Galileo,

who's now a father of three illegitimate children.

The memory of the pendulum is yet to surface

because by now, Galileo's completely obsessed by astronomy

and the new invention of the telescope.

In 1610, he discovers that Jupiter has its own orbiting moons

which eclipse in a regular and predictable way.

He proposes that sailors use these movements

as a celestial time-keeper in the sky.

Theoretically, it's a brilliant idea.

But in practice, bobbing around in the middle of the ocean,

it's almost impossible to make precise astronomical readings.

I mean, I'm having a hard enough time just seeing that seagull over there,

much less figuring out what's happening with the moons of Jupiter.

OK, so that doesn't work.

But it's this dead end which finally brings Galileo

back to his original insight into the equal time of the pendulum.

Staring at the heavens reminds him of gazing up inside the cathedral.

Those swinging altar lamps.

The pendulum experiment of equal time.

The desperate need for an accurate time-keeper.

And bingo!

Galileo finally realises

that a pendulum could be used to regulate clocks.

So this is what he comes up with -

a design for a perfect swinging pendulum.

Its beats are equal

and it can be used to control the hands of the clock.

It's a revolutionary idea,

but Galileo's now near the end of his life

and doesn't get the chance to test it at sea.

This is a classic case of someone failing to solve a problem,

but, in failing, they hit upon an even more important idea.

Galileo never wins any of the longitude prizes,

but he does design one of the most important inventions of the age -

the pendulum clock.

This idea that's taken decades to come into focus

is now going to have massive repercussions for the modern world.

Within 15 years, Dutch astronomer Christiaan Huygens

produces the first true pendulum clock.

This technology is now 100 times more precise than previous clocks,

with the loss or gain cut down to just one minute a week.

More accurate clocks also mean better health care.

Now able to record the passing of seconds,

doctors start using clocks for the first time to measure our pulses.

The craft of building accurate clocks has another payoff.

Some 100 years later, Englishman John Harrison

finally solves the longitude problem

by inventing the marine chronometer,

thanks to ever-evolving clock-making expertise.

With better command of the seas,

maritime trade and exploration now flourish.

In 1831, a ship sails to the Galapagos Islands

to fix the longitudes of foreign lands with the help 22 chronometers.

On board is the young Charles Darwin,

whose findings there form the basis of the Theory of Evolution.

All this evolved thanks to the pendulum clock,

first imagined by Galileo,

which will continue to be our best way of measuring time

until the early 20th century.

Here in San Francisco,

we have the largest wind-up-dialled mechanical clock in the world.

It's housed inside the 73-metre tower of the iconic Ferry Building,

and was built in 1898.

Here's the pendulum itself. It's really cool to see this,

this is really the first great breakthrough

in the measurement of time.

Dorian Clair has been repairing clocks since he was eight years old.

This would have been kind of state-of-the-art for a clock

at the turn of the century back then?

Actually, it's still state-of-the-art.

There's no pendulums that have been invented that work better.

How accurate do you think it was?

When it was built, it was guaranteed to be within five seconds a week.

Right. Do you think if Galileo could see this right now,

he would instantly recognise what this was?

Oh, he probably would come up with some improvement.

-But it's been working...

-He's so annoying that way!

"I got a better idea how to do it!"

The pendulum clock sets a new standard

in the accurate measurement of time.

But back then, unless you were a sailor, you didn't really have

that much need for minute-by-minute accuracy in your clocks.

I mean, most people were living pastoral lives.

They didn't have office buildings with meetings

or trains and ferries to catch and appointments all through the day.

But then, in the middle of the 18th century,

something very interesting begins to happen.

By the 1760s, British clock-making

is among the most technically advanced trades in the world.

Craftsmen have devised tools

to make tiny, precision-made parts of gears and screws.

And this expertise is up-scaled to make much bigger,

more sophisticated machines like steam engines and mechanical looms.

All of which kick-starts what is perhaps

the biggest social upheaval ever -

the Industrial Revolution.

Suddenly, our experience of time changes for ever.

People leave the fields to work in new factories.

They're no longer working by sunlight or paid by the task.

Workers must clock in for the first time en masse for 14-hour shifts.

They rebel by showing up late for work.

Factories hire "wakers" to rouse them from their sleep on dark mornings.

The disruption to our body clocks gives birth to a major new trade

in the drugs of tea and coffee to help us stay awake.

We're now working on artificial time,

breaking away from a life that followed the sun.

When we think about the technology that created the Industrial Age,

we naturally think of thunderous engines and steam-powered looms.

But imagine some alternate history where, for whatever reason,

time-keeping technology lags behind

the other machines that made the Industrial Age -

would the Industrial Revolution have even happened?

You can make a reasonably good case that the answer is no,

because beneath the cacophony of the mills,

another softer but equally important sound is everywhere -

the steady ticking of pendulum clocks, quietly keeping time.

Time in the early 1800s

is still in the hands of those who can afford it,

giving even more power to the powerful,

to nation-builders, and mill-owners and aristocrats.

And watches were exclusive status symbols for the privileged few.

Common people had no hope of ever owning a watch,

which made it so much harder for them to gain control over their own time.

The story of how we all got to wear watches

would have far-reaching and unexpected consequences

and change everything from our moral values to the way we wage war.

So, what are we looking at here?

So, this is a very rare piece called the Minute Repeater.

'I've come to meet Lawrence Pettinelli

'at the traditional watchmaker Patek Philippe,

'to shop for a watch 19th-century style.'

Not to be too indelicate about this, but what does one of these go for?

This particular piece in rose gold

-is 739,000 Swiss francs.

-OK, in dollars?

In dollars, approximately 750,000 at the current exchange rate.

750,000, that's worth more than my arm.

That's impressive. OK, so, why is this so expensive?

Well, first of all, it takes almost two years to produce,

and you have very few watchmakers who can actually do this work.

Just as in a 19th-century workshop,

these watches are handmade with exquisite precision

and they're still status symbols today.

Look at all those tiny little intricate pieces down there.

It's almost like a little city.

Some of these components are as small as the breadth of a human hair.

So, they're actually screwing these things in by hand?

-They're screwing them in by hand.

-It doesn't seem... I mean,

it feels like you would have to train, like, fleas to actually,

you know, put those screws in. That's extraordinary.

We're used to it, now in the Electronics Age,

that our world is populated by all these objects

that have this meticulous, tiny, little mechanical universe to them

that you can only see through a microscope.

But in the middle of the 19th century,

a watch like this would have been really the only object in our lives

that would have that level of precision engineering to it.

It would have been a real object of wonder.

I've also carved my initials into this one. No-one will ever know.

Today, you don't have to spend a fortune to buy a watch,

you can pick one up on the street for a couple of bucks.

But back in the mid-1800s,

handcrafted luxury watches were the only kind on the market.

The next leap forward in time and who could own it

would come to us thanks to this guy - Aaron Dennison,

a man so obsessed with his vision that he defied public opinion,

earning himself a local reputation as a madman.

But Dennison's no killer, nor is he insane - he's an ideas man.

In 1826, the 14-year-old Dennison

is working in his father's cobbler shop.

And he sees his dad painstakingly custom-making leather soles

for each individual, and so one day he says to his father,

"Why don't we make a batch of leather soles all at once for popular sizes?"

And this ends up saving his father a lot of time.

But the usefulness of Dennison's idea won't end there.

Dennison can't help but hatch new business ideas.

Aged 27, he's got his own watch shop.

He gets first-hand insight into this laborious boutique industry

where many different people hand-produce many different parts

to make a single watch.

People are convinced this is the only way to do it.

In 1840, he causes a storm of controversy by predicting

that in ten years' time, watches will be made by machinery.

The public pour scorn on the idea.

One magazine goes so far as to call him the "lunatic of Boston".

But as with Galileo,

Dennison can't drive progress by simply accepting conventional wisdom.

In the face of ridicule, he sticks to his vision.

Visiting a nearby armoury in Springfield, Massachusetts,

Dennison sees the weapons industry is making guns faster and cheaper

by producing interchangeable parts -

that is, identical parts made in batches by machines.

Now, a hunch from his father's shoe shop

and the experience of clock-makers

and his observations of the rifle industry all start to morph together

into the beginnings of a commercial plan.

Dennison is going to make machines

that can produce interchangeable parts

so that he can mass-produce watches all under one roof.

That's the thing about great innovations -

they're often not stand-alone flashes of inspiration,

but they're created by observing something in one field

and bringing it over to another.

Transferring the idea.

For example, people think that Henry Ford invented the production line,

but what he actually did was take the idea from Chicago's meat-packers,

who removed cuts of beef from a carcass

as it was passed along a trolley until nothing was left.

Ford reversed this process for the production of his Model T,

creating the assembly line and making cars affordable to the masses.

Just like Ford, Dennison brings together innovative ideas

to help millions afford something they could only dream of.

After finding investors,

Dennison builds this huge factory in Waltham, Massachusetts.

It's a tremendous operation,

it's filled with nearly 100 employees operating complex machinery.

It's the first production line for manufacturing watches.

Mass-producing the relatively large parts for guns is one thing,

but it's completely new territory to mass-produce components

the size of a flea for watches.

New machines need to be invented to pull it off,

and this doesn't come cheap.

Despite glimmers of hope,

Dennison and his team are constantly going back to the drawing board.

But Dennison's like a dog with a bone.

He's so obsessed with his idea that he runs out of money,

has to sell his factory

and suffer the indignity of returning as an employee.

But ironically, Dennison's about to be rescued from his personal crisis

by a crisis unfolding on the national level.

The outbreak of the Civil War brings Dennison a new business idea.

Despite being ordered by his new boss not to pursue any new projects,

what does this crazy guy do?

He waits until the boss is away on a honeymoon

and orders work on another watch, a cheap model with a patriotic name

that could be marketed to a captive audience with time on their hands.

And this is what they produce.

A simple, inexpensive watch, targeted at soldiers and named after

one of the signers of the Declaration of Independence - William Ellery.

It's a steal at 13, and a fraction of previous watch prices.

The so-called "soldier's watch" accounts for 45% of Dennison's sales.

The Ellery watch is a break-out hit -

over 160,000 of them are sold, an unprecedented amount.

Even Abraham Lincoln has one.

Dennison has democratised time.

In just two decades, watches become ten times cheaper,

making them affordable to a mass market.

The watch becomes the first must-have hi-tech gadget.

Thanks to a crazy idea,

a transformation of how we experience time now takes place.

With more and more people carrying watches,

we start to synchronise our actions.

Before wide access to time-keepers,

battles were started by the unreliable boom of a cannon.

The Civil War Battle of Vicksburg in 1863

is the first ever initiated by the synchronisation of watches.

This forever changes the way we fight.

Watch-ownership spurs an obsession with punctuality.

It becomes a social virtue to keep good time,

and people buy watches for their children

to enhance their chances in life.

Cookbooks evolve from never using time references

to now offering recipes with timed instructions.

Team sports start to form national leagues

which run on much stricter schedules,

allowing masses of people to attend at a fixed hour.

Time gives us the power

to organise and improve the efficiency of our lives.

But there's a deep irony here

because the more we start to own our own time,

the more time starts to own us.

We can finely tune our schedules,

but we're constantly worrying about them

and getting anxious about being late.

So not only do watches liberate us,

but they also start to enslave us.

But 130 years ago,

there were other consequences of us all owning watches.

As more and more people in the 19th century

can own a watch and synchronise their activities,

it slowly dawns on society that it's not just groups of people

but whole nations that need to get on the same clock.

856 contact London on 118...

..Charlie, hold short 27 left...

Contact Tower, channel 11...

This is Heathrow Airport,

which transports more international passengers

than any other airport in the world.

Turn right onto taxiway alpha, holding point is Saturn...

The people in the Air Traffic Control Centre coordinate

over 1,300 flights a day

with planes landing and taking off every 45 seconds.

It's a miracle of scheduling, and now I'm going to have a go at it.

Not for real, but in their simulator with trainer David Marshall.

Just like in the real tower,

the most important piece of equipment in the whole room

is the simple, everyday clock.

Every second counts as a departures controller.

If you can save two seconds

per airplane, per hour, it would mean

an extra two or three departures an hour -

that can be as many as a thousand people.

So I probably shouldn't just check Facebook while I'm in the middle

-of this?

-No.

-Just really stay focused on the job.

OK. All right.

He's already on the roll, he's already moving around the corner.

So we can say, you're going to say it,

"Turkish five hotel mike, line up."

'OK, so I'm not a natural.'

He's going out to the east.

We've got this guy who's going to turn to the west,

-there's our first landing.

-I'm really confused.

-If we look up...if we look out there...

-Yeah, yeah, I can see,

OK, that's pretty cool...

'Every single landing and takeoff is recorded to the second.'

When he gets airborne,

as soon as his nose wheel comes up, you hit that button there.

Planes are converging at Heathrow from 180 different destinations,

so it's pretty important they're all using one standard time.

Every air traffic clock is in Greenwich Mean Time.

Every air traffic clock in the world?

All over the world we're all working on the same time.

OK, we've now wasted 20 seconds.

-He could have been airborne 20 seconds ago.

-Sorry!

So how did we get to a global system of standardised time?

Well, it was all thanks to

an egomaniacal railroad clerk 150 years ago.

A man who went head to head with public opinion

to help launch a new dawn for telecommunications and broadcasting.

In the middle of the 19th century,

the railroad is transforming America.

In just a few decades, over 100,000 miles of track are built,

connecting the continent for the first time.

It's a heroic chapter in American history,

but it creates an unexpected problem.

Here's the issue.

The railroads are connecting all of these towns

that have historically maintained their own individual time

set by a local reading of the sun.

In the 1880s, there were hundreds of towns, each using its own local time.

Each differing not by the hour, but by the minute.

There were 23 different times in Indiana,

27 in Michigan

and 38 across Wisconsin.

What makes it even worse is that,

in addition to each town having its own time,

each railroad had its own time.

And there were 50 different railroads!

So back then, taking a journey by rail was something of an adventure

which could leave you more than a little confused.

So, you know what it's like taking a train ride today.

You can kick back, read a book, listen to some music.

But imagine what it would have been like in 1870 trying to take a train.

Let's say we're travelling from New Haven to New York.

And so I get on the train at 12 o'clock New Haven time

and it takes us two hours to get to New York.

So we should be arriving in New York at two o'clock.

But in fact, in New York time, that's technically 1.55.

But the train we're on is actually running on Boston time,

so that means we're actually pulling into the station in New York

on Boston time at 2.17.

But then we're, like, making a connection to a train to Baltimore

that's running on Baltimore time,

so that train is actually leaving the station at 2.07,

which seems to be in the past.

I mean, you have to be a math major to figure out what time it is!

If you think that was confusing for the individual passenger,

imagine what it was like for this guy, William Allen,

who was Secretary of the General Time Convention,

which meant that he was in charge of reconciling the rail timetables

for the entire US system.

Most people would run away from this mathematical nightmare,

but Allen seems mysteriously drawn to it.

Professor Alexis McCrossen can shed some light on the matter.

What really motivates Allen to get involved

in the reinvention of time, basically?

First and foremost, he is opportunistic.

He's an egomaniac

and this is his opportunity to make a name for himself.

Allen realises that his path to greatness

is in managing the schedules of all of these railroads

that are proliferating like mushrooms after a rainstorm.

I like that idea - the path to greatness

being publishing railroad timetables.

That's... "I'll be famous beyond imagination!"

"Timetables, that's it!"

But it's 1881, and Allen seizes the moment.

And what he does is he introduces

the idea of time zones,

so not just of standardising the time,

not just of creating one railroad time

that all the railroads would follow,

but of dividing the Standard Time in the United States

into four zones.

So this is the original map that Allen actually drew.

I mean, this is kind of the blueprint for the time-zone system, right?

-I mean, he actually hand-coloured these different divisions?

-Yep. Yep.

He figured out where to divide the time zones

and he divided them at the basis

of where different railroad lines ended, where they're terminated.

And so he didn't exactly follow state lines,

but he followed the geography of the railroad.

Allen has a major fight on his hands

because the proposal of Standard Time is a deeply controversial idea,

and many Americans are afraid of it.

Allen starts an enormous lobbying campaign,

writing nearly 600 letters and countless circulars

to mayors and city councils

to try and cajole and arm-twist them into signing up.

But there's fierce opposition to the prospect of change.

A paper in Cincinnati writes, "It's simply preposterous.

"Let the people of Cincinnati stick to the truth

"as it is written by the sun, moon and stars."

And these are all the original circulars that he sent out.

-Look at how many of them there are.

-Oh, hundreds.

-It's amazing.

"Are you in favour of the hour system of time standards

"as illustrated by the accompanying map?"

And we've got this great kind of 19th century, "YES!"

But some people, this guy, he answers, "I think not."

That's right. And check this out. Then he writes on the back. "Why?"

He says, "Dear sir, the reason why I say no

"to the questions on the other side of the sheet

"is because it would be an entire revolution in our time."

I mean, that's it, it's a revolution in our time.

That's what he's trying to put in motion.

After an epic seven-month battle to wrestle America's chaos of times

into a simple system, Allen finally triumphs.

All of which leads to one of the strangest days

in the history of time - November 18th, 1883.

The day of two noons.

The first noon rings out at St Paul's in the New York local time.

And then, four minutes later, there's another noon.

The first ever 12pm Eastern Standard Time,

announced by the bells of Trinity Church.

BELLS TOLL

As the bells ring out,

the new Standard Time is sent down the telegraph lines

for all the railroad stations to set their clocks to.

America goes from hundreds of times to just four.

And rail travel becomes a hell of a lot easier.

Just a few weeks after his time system is implemented,

Allen writes in a letter,

"The adoption of the Standard Time system is an event

"which is likely to be noted in the history of the world, for all time."

I mean, OK, it may sound like he was a little full of himself,

but, actually, he might have had a point

because when you think about it, it's not just railroads.

Any time you take a flight somewhere or schedule a phone call

with someone living in another city,

you're living inside of standardised time.

Thanks to Allen's dogged crusade,

America becomes a modern nation by embracing one single system of time.

The very next year,

Greenwich Mean Time is set up as the international meridian

and the whole world is divided up into time zones.

With this new web of time wrapped around the world,

we are now more closely connected to foreign countries

through improved trade, travel and communications.

We also become closer to our fellow citizens through broadcasting.

Now, for the first time ever,

millions of us could sit down to a show at exactly the same moment.

-RADIO:

-'In the deciding game of the Eastern League Baseball...'

The story of time in the 20th century is all about clocks

shaving the second down to smaller and smaller increments.

And some of these tiny clocks

are inside our laptops and our cellphones.

It turns out you can't make a computer

without a super-accurate clock.

And all of these devices together combine to speed up our lives

in a thousand different ways.

And that's the funny thing about modern clocks.

The better we get at measuring time, the less we seem to have of it.

But the most important change in our measurement of time would come

from a scientific breakthrough that had both catastrophic

and transformative consequences for the entire world.

Atomic physics brings us man's most destructive weapon,

but it also provides us with a platform,

an environment that encourages people to think big,

bringing revolutionary ideas to energy and medicine.

This pioneering work in physics will transform our relationship to time,

revealing secrets about our ancient past

and also helping us predict our future.

In October of 1967, a group of scientists gathered in Paris

and changed the very definition of time itself.

They decided that the astronomical time that humans had used

for all of history simply wasn't accurate enough any more,

and they decided to trade the largest object in the solar system

for one of the smallest.

And we entered the age of atomic time.

You could say that time as we know it is largely thanks to this place -

the US Naval Observatory in Washington DC.

This building has a name

that sounds like something out of a George Orwell novel -

the Directorate of Time.

These are some of the most accurate clocks

-that human beings have ever designed?

-Yes.

You might think that the clocks we use

are still ultimately set by the rotation of the Earth.

But in fact, today we measure time by tracking the behaviour of atoms,

using atomic clocks like these.

The man in charge here is "time lord" Dr Demetrios Matsakis.

He's got some insane statistics.

How do we define a second now?

A second is defined as 9,192,631,770

periods of oscillation of an undisturbed caesium atom.

I hope all the schoolkids have memorised that.

Just like a pendulum,

atoms can be used to measure equal intervals of time

by reading the regular pulses of energy they emit.

These are the most accurate measurement systems

ever made operationally by mankind.

-In terms of measuring anything.

-Of measuring anything.

A good caesium clock on a bad day

will differ by about five nanoseconds in its time

from what we thought it would be.

-So a nanosecond is one...

-A billionth of a second.

"A billionth of a second"...

The thing is, when the first atomic clocks were built in the 1950s,

their formidable power to break down the second

confirmed something extraordinary.

The Earth's rotation is slowing down.

Back when T Rex roamed the world,

a day was only 23 hours long.

And ever since, the solar day has been slowly increasing in length.

Not only that, atomic time also showed us

that the Earth's rotation is not always consistent.

To compensate, a leap second was added to the clock.

But this intervention into time has been a little controversial.

The leap-second argument is that some people think

-we don't need this extra second.

-That's right.

They think that adding, including that second is too disruptive.

There are many stories about web pages going down,

airlines having to shut down because their computers went offline

when they detected a one-second jump and didn't know it was coming.

That shows you how dependent the world has become

on this level of accuracy in time-keeping.

You tell a computer, "Oh, there's an extra second in this day,"

and an entire airline system goes down.

Yes, that could happen.

You probably won't have noticed,

but since 1972, 25 leap seconds have been added to our lives.

Once these clocks have ordained what time it is,

an intelligent average - the universal Standard Time -

is then distributed by this monster clock.

This is where US Standard Time is broadcast out to the entire country.

Every time you, you know, check your phone to see what time it is,

you're ultimately getting that information

from this clock in this room.

I mean, it's actually kind of bizarre that I'm standing right next to it.

I feel like I could fiddle with some of these buttons

and, like, the entire country would be late for work!

Atomic clocks are now so accurate

that we can measure time with a drift of just a single second every -

wait for it - five billion years!

And increasingly, these clocks are important,

not just for finding out what time it is,

but for finding out where we are.

That's because every time you look at your smartphone

to assess your location, you're calling on ultra-precise atomic time.

So, let's say I'm in a big city

and I want to find out where the nearest coffee shop is.

I take out my phone and up above me there are 24 GPS satellites.

They're effectively giant clocks in orbit,

only they're accurate to a billionth of a second.

My phone gets a signal from four of them,

they're basically just sending a time-stamp.

Only there's a slight difference between each of the signals.

Using those differences in time,

my phone can calculate its exact distance

from each of the satellites,

enabling it to fix its location with pinpoint accuracy.

But GPS satellites do way more than get us from A to B.

For starters, their clocks coordinate the system used by cash machines

and other financial transactions.

GPS gives us cheaper food thanks to robotic farming.

Not to mention all the GPS apps that help us peer around the corner

to hail a taxi or figure out when the next bus is coming,

or even to find the nearest coffee shop.

It's incredible to think about it,

but all this GPS technology is ultimately dependent

on electrons dancing around an atom.

But atomic physics would usher in

another revolution in our measurement of time.

And this one wouldn't tell us where we need to go,

but instead, where we've come from.

This is about as far from the modern world of time as you can get.

I'm in California's Anza-Borrego Desert.

And looking out here, I can't see any sign of civilisation.

And the whole contemporary rhythm of split-seconds,

it's just almost impossible to imagine.

Here, you're living on geologic time.

This is where, millions of years ago,

the notorious San Andreas Fault was created in Southern California.

It's a barren and beautiful landscape

but before this, it was a lush savanna with rivers and lakes,

populated by exotic animals,

sabre-tooth cats and mammoths.

And before that, it was a vast ocean teeming with aquatic life.

So how do we know this story?

Well, in part because we invented a very different kind of clock.

For centuries,

we had no idea exactly when the first humans spread across the globe...

or exactly how to date the rich source of fossils

scattered all over the desert floor.

That is, until this brilliant woman, came along - Marie Curie.

In the 1890s,

she made history by studying the new field of radioactivity.

She and her husband Pierre showed the world

that radioactive atoms decay at constant rates.

Carbon 14, for example,

decays by 50% every 5,730 years.

Other elements have wildly different rates of decay,

but each one is regular and predictable.

Once again, science had delivered the crucial concept

of equal intervals of time,

and the idea dawned that rocks could be clocks.

Clocks that don't tick by the second,

but on the scale of centuries or millennia, and deep into the past.

So, there was a...basically, above a certain point here,

-there was an ocean.

-Yes, about 6.25 million years ago.

Palaeontologist Lyndon Murray

uses radiometric dating to read the landscape.

It has an error margin of just 2-5%.

And so is this process going to continue,

are we just going to get ever more precise?

Every rock will have its birthday?

Well, you have a goal, and that's the goal.

I guess this is a basic question, why do we do this?

The geology and dating of what happened here

can help in determining a record of past climate,

of eight million years, actually.

So we can see a sequence of events that happens,

and how and perhaps why the climate changes.

So in a way, all these technologies that let us look back in the past

with such precision are actually also enabling us to predict the future?

Yeah, yeah, I've always thought that.

Radiometric clocks have given us this amazing time machine.

I mean, they've helped us pinpoint exactly when humans

first crossed the Siberian land bridge into the Americas.

But they've also helped us predict the future.

And in doing that, they may help us tackle

one of the 21st century's most important problems -

how to solve climate change.

So in a way, clocks aren't just about measuring time,

they can also help us understand where we came from

and where we're headed.

In the 400 years that have passed

since Galileo first started tinkering with the equal time of the pendulum,

clocks have transformed just about every facet of modern life.

And there are those who say that our modern, accelerated,

sped-up world is too frenetic,

and they long for the slower pace of a pastoral life

when our clocks were set by the rising and the setting of the sun.

But the thing about the modern clock

is that it's never just been about time.

In a very real sense, our ability to measure time

in increasingly small increments

has made the world a smaller and more connected place.

As to what the clocks of the future will bring us -

for that, only time will tell.