Original subtitles

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.

[ ♪♪♪ ]

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, hand-crafted 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 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.

Woo! Oh, boy.

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.

I'm Steven Johnson.

I write about ideas and innovation.

And this is the untold story of How We Got to Now.

[ ♪♪♪ ]

How We Got to Now was made possible in part by

the Corporation for Public Broadcasting

and by contributions to your PBS station from...

[ ♪♪♪ ]

Sounding 7-5-8 ballast to meet the keel.

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

this is the place to come:

the nuclear submarine USS Asheville.

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! - Up scope.

The only view Lt. Commander Jason Deichler will have

of the outside world is through this periscope.

That's a really clear image,

but, gosh, it would be amazing to go for like 30 days

and that's your only glimpse at sunlight.

That's our only glimpse of topside.

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

I feel like -- can I just fulfill a lifelong fantasy here,

- if you don't mind? - Absolutely.

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

Dive! Dive!

[ horn blares ] Oh!

[ ♪♪♪ ]

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 Asheville

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 you do it?

Well, for us, we have limited amount of resources

and men onboard 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 stand watch.

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

but everybody's on a different clock, right?

Somebody's nighttime 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,

because 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.

And we kind of become masters of our own time underway.

[ gulls cawing ]

Most of us would have a hard time

living on the 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.

[ ♪♪♪ ]

[ bell tolling ]

For millennia, we'd rise with the sun

and go to bed at dusk.

The very notion of timekeeping 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, timekeeping 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've been as useful as a satellite dish.

[ ♪♪♪ ]

[ crows ]

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 center of our solar system.

But in 1583, he was just an unknown student

who would discover something that would forever change

the way we traveled, traded, and worked.

You ready? Hold it up. Use all your strength!

Perfect.

- Thank you! - Sure, sure.

Thank you so much!

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? 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 revolutionize 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 marvelous 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 and 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.

Woo! Oh, boy.

Ships in Galileo's day were sailing blind

over vast new distances

and frequently meeting with disaster.

[ thunder rumbles ]

For the New World to be conquered,

something had to be done.

JOHNSON: 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.

[ man chuckles ]

- 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 realize

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 --

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 onboard,

they soon end up completely lost.

[ gull caws ]

I have to get us back on course here.

[ chuckles ]

[ ♪♪♪ ]

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 timekeeper 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 on the moons of Jupiter.

Okay, 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 timekeeper,

and, bingo, Galileo finally realizes

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 is 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 clockmaking 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 of 22 chronometers.

Onboard 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.

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 clockmaking

is among the mt technically advanced trades in the world.

Craftsmen have devised tools

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

And this expertise is upscaled

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 forever.

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.

[ knock on door ]

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.

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 a minute repeater.

I've come to meet Lawrence Petinelli

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?

Well, this particular piece in rose gold

is $739,000 Swiss francs.

Okay, in dollars?

In dollars, approximately $750,000

at the current exchange rate.

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

Just as in a 19th-centy workshop,

these watches are handmade with exquisite precision,

and they're still status symbols today.

Look at all these tiny little intricate pieces

you can see down there.

It's almost like a little city.

Some of these components are as small

as the breadth of a human hai.

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

They're screwing them in by hand.

It doesn't seem phys-- I mean, it feels like

you would have to train fleas to actually 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've been

really the only object in our lives

that would have that level of precision engineering to it.

It would've 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 madma.

But Dennison's no killer, nor is he insane.

He's an ideas man.

[ woman screams ]

In 1826, the 14-year-old Dennison was 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.

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

He gets firsthand 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 10 years' time,

watches will be made by machinery.

The public pours 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 armory in Springfield, Massachusetts,

Dennison sees that 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 clockmakers

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.

Dennison's revolutionary idea

is to help millions of people 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 this 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 watc"

accounts for 45% of Dennison's sales.

The Ellery watch is a breakout hit.

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

Even Abraham Lincoln has one.

Dennison has democratized time.

In just two decades, watches become 10 times cheaper,

making them affordable to a mass market.

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

[ ♪♪♪ ]

Thanks to a crazy idea, a transformation

in how we experience time now takes place.

With more and more people carrying watches,

we start to synchronize our actions.

Before wide access to timekeepers,

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 synchronization 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.

[ cheering and referee whistles ]

Time gives us the power to organize

and improve the effiency 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 synchronize 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.

[ engine roars ]

Spirit 856, contact London on 118.825.

Hold short 2-7 left, contact tower channel 11.

This is Heathrow Airport,

which transports more international passengers

than any other airport in the world.

Turn right at taxiway alpha, holding point at saturn.

The people in the air traffic control center

coordinate over 1,300 flights a day

with planes landing and taking off every 45 seconds.

[ engines roaring ]

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 departure 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 1,000 people.

So I probably shouldn't check Facebook

while I'm in the middle of this on the screen here.

I should just really stay focused on the job.

Okay. All right.

He's already on the roll,

he's already moving around the corner,

so we can say -- and you're going to say it, Steven --

"Turkey Five Hotel Mike, line up 091."

[ exhales sharply and laughs ]

Okay, so I'm not a natural.

He's going out to the east.

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

- There's our first lander. - I'm already really confused.

If we look out --

Yeah, I can see them moving. 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 that 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.

Okay, we've now wasted 20 seconds.

He could've been airborne 20 seconds ago.

Sorry!

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

[ engine chugging and steam hissing ]

[ bell ringing ]

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.

[ bell ringing ]

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 an 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.

[ steam whistle blowing ]

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've been like in 1870,

trying to take a train.

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

And so I get on the train at 12:00 New Haven time,

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

So we should be arriving in New York at 2:00,

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 ans

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!

[ ticking grows louder and louder ]

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 U.S. system.

[ ♪♪♪ ]

Most people would run away from this mathematical nightmare,

but Allen seems mysteriously drawn to it.

Professor Alexis McCrossen can shed some light the matter.

What really motivates Allen to get involved

in the reinvention of time, basically?

First and foremost, he's opportunistic.

He is an egomaniac.

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

Allen realizes 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 of 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 standardizing 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-colored

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 ide,

and many Americans are afraid of it.

[ alarm ringing ]

Allen starts an enormous lobbying campaign,

writing nearly 600 letters and countless circulars

to mayors and city councils

to try to 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 how many of them there are!

- Oh, hundreds. - It's amazing.

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

as illustrated by the accompanying map?"

And you'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 18, 1883,

the day of two noons.

[ bell tolling ]

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 12:00 p.m. Eastern Standard Time,

announced by the bells of Trinity Church.

[ bells ring in descending scale ]

[ ♪♪♪ ]

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, okay, it may sound like he was a little full of himself,

but actually, he might've had a point.

Because if you think about it, it's not just railroads.

Any time you take a flight somewhere

or schedule a phone call with somebody

living in another city,

you're living inside of standardized 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 clor 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.

ANNOUNCER: Tonight, in the deciding game

of the Eastern League baseball pennant race...

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 cell phones.

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.

[ loud explosion ]

[ ♪♪♪ ]

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 physis

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 anymore.

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 U.S. Naval Observatory in Washington, D.C.

This building has a name that sounds like something

out of a George Orwell novel: the Directorate of Te.

These are some of the most accurate clocks

that human beings have ever designed?

Yes.

You might think that the clocs we use are still ultimately st

by the rotation of the Earth, but in fact,

today we measure time by tracking the behavior of atoms

using atomic clocks like these.

The man in charge here

is time lord Dr. Demetrius Matsakis.

He's got some insane statistics.

How do we define a second now?

A second is defined as

9,192,671,770 periods of oscillation

of an undisturbed cesium atom.

[ laughs ]

That's... I hope all the schoolkids have memorized 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 system

ever made operationally by mankind.

In terms of measuring anything.

In measuring anything.

A good cesium clock on a bad day

will differ by about 5 nanoseconds

in its time from what we thought it would be.

So a nanosecond is one...?

- A billionth of a second. - One 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 ineasing 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 tie

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 timekeeping.

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 U.S. standard time is broadcast out

to the entire country.

Every time you 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 kind of 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 --

5 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,

and 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

that's 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 just 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.

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

buinstead 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-Barrego Desert,

and looking out here, I can't see any sign of civilization.

And the whole contemporary rhythm of split seconds

is 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 savannah with rivers and lakes

populated by exotic animals -- saber-toothed 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 -- basically, above a certain point here,

there was an ocean.

Yes, about 6.25 million years ago.

Paleontologist Lyndon Murray uses radiometric dating

to read the landscape.

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

I guess there's a basic question of why do we do this?

The geology and dating of what happened here

can help in determining a record of past climate

of 8 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 into 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.

In the next episode, I'm exploring how glass

is instrumental in science's greatest revolutions.

From a physics teacher who fires crossbows...

The strange physical properties of glass

would open up a whole new world of possibilities.

to the man on the moon,

glass has changed the way we view and share

our world today.