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The mastery of time.

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This is one of humankind’s
biggest obsessions.

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Since humans learned how to count,

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we’ve tried to understand and measure
the observable phenomena of time.

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Whether past, present, or future,

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time is undoubtedly one
of the most complex notions

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in our universe.

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If we send satellites
into space today,

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it’s thanks
to this rudimentary instrument,

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a stick that projects a shadow.

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Over the centuries, making time
has been the object

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of a perpetual scientific quest.

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From the moment we control time,
we control people.

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Today, a group of experts made
up of astrophysicists,

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engineers and historians,

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is following in the footsteps
of these genius inventors,

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who revolutionized our perception
of time and of the world.

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Pacôme Delva: In fact, with relativity,

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Einstein showed that absolute rigid time
does not exist.

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The question Huygens
posed was, how to ensure that

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between each "tick" and "tock",

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we always have one second.

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This epic gave birth
to extraordinary machines.

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Thanks to them, men have tamed
the Earth’s cycles.

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They escaped the ocean’s traps,
traced maps,

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secured transport,

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built the foundations
of our modern economy,

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before launching clocks into space.

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Precious ally or formidable enemy,
time dictates the rhythm of our lives.

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THE TIME FACTORY

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Perched on the heights
of France’s capital,

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the Paris observatory looks
like a sleeping ship.

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Yet, within this secular institution
is the heart of a machine

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that never stops beating.

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It is here that for 350 years, men
and women have made our common time.

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This evening the astrophysicist
Pacôme Delva

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is accompanied by Denis Savoie,

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science historian, and specialist
in time measurement.

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Like the astronomers of Antiquity,

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the two scientists observe the movement
of the stars,

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a sign of the passing of time.

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Not yet. There is Saturn.

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You can really see the stars moving here,

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and when you look in the eyepiece,
it's very obvious.

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If we don’t use the motor to follow
the movement of the sky,

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in fact, the planets move
out of the eyepiece very quickly.

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So, we really see time passing.

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This is linked to the Earth's rotation
on itself.

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And as our position on Earth is fixed,

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we see the whole sky moving.

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FRANCE 15000 BC

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To find the origin of the measurement
of time,

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we must go back to the prehistoric era.

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The measurement of time begins
with the first humans.

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We have no writings, but we suppose
it was by observing the sun

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and the alternation of day and night.

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Then the discovery the Moon,

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that illuminates the nights.

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And the Moon resumes the same
configuration after about 30 days.

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These two stars quickly become the masters
of the division of time in the long term.

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At its inception,

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the measurement of time was based
on careful observation

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of natural phenomena.

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The survival of our distant ancestors
depended closely

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on the position and rotation of the Earth

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in relation to the sun.

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Thus, the day is devoted to hunting
or gathering,

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at night, Palaeolithic peoples protect
themselves from the cold and predators

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while awaiting the return
of the solar star.

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Before taming time,

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these nomads live according to the rhythm
of nature and the seasons,

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synchronized to the cycle of plants
or the movement of herds of herbivores.

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The measurement of time is born
with mathematic measurement.

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And certain testimonies claim it starts
with the Babylonians and the Egyptians.

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Here, in Iraq, 5 millennia ago,

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the Babylonians living on the banks
of the Euphrates

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left us a scientific legacy
in the field of mathematics.

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BABYLON 3000 BC

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Engraved within tight lines
in cuneiform script,

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clay tablets reveal
how Babylonian scholars divide the year

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into 12 months of 30 days.

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These first calendars based
on the cycles of the moon

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make it possible to anticipate the return
of the seasons,

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the periods of rain and strong heat

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which return according
to the lunar cycles.

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The Babylonian’s astronomy
was extremely elaborate.

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They were able to predict
in the long term the position of the sun,

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the moon and the planets in the sky.

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They had what are called ephemeris.

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This means
they have a perfect mastery of time

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and this observation of time was done

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with the most rudimentary instrument
of astronomy,

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the gnomon which makes it possible

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to determine the fundamental constants
of astronomy.

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Denis Savoie is a specialist
in gnomonics,

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the art of designing and tracing sundials.

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With this measuring instrument,
the gnomon,

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Babylonian scientists measured time.

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Thanks to mathematics,

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this data enabled
them to better control time.

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This instrument dates back
to ancient times,

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2000 years before Jesus Christ.

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If we send satellites into space today,

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it’s thanks to this rudimentary
instrument that projects a shadow.

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But this gnomon is very simple.

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It's a stick that we try
to plant vertically, on a flat surface

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and we’ll watch the end of the shadow.

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And throughout the day,
at regular intervals,

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we use pebbles to mark the end
of the shadow.

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We obtain a curve on the ground,
a hyperbole.

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And we see there is a time of day
when the shadow is the shortest.

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At this time, the Sun
is in the geographic South,

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at its highest.

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And this is where Babylonian astronomers
measure the length of the shadow.

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And from the measurement of this length
they deduce parameters such as latitude,

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obliquity, length of the seasons,
solstice, etcetera.

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The shadow of the gnomon shows that

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the Earth rotates both on itself
and around the sun,

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with an inclined axis of rotation.

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It is this inclination
which causes the variation

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of the height of the sun during the year,

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and which therefore
causes the phenomenon of the seasons.

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Babylonian astronomers observe
that at the winter solstice

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the sun is lowest in the sky

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and that it produces a very long shadow,

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at the summer solstice the sun
is at its highest

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it therefore produces a very short shadow.

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Scientists also note two periods
during the year

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when the length of the days is equal
to the length of the nights

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these are the equinoxes.

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Thus, the solstices and the equinoxes
divide the year into four periods,

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spring, summer, autumn and winter.

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We're starting to master these cycles

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and time quickly becomes a major issue.

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Because it allows the forecasting
of phenomena,

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the organization of society,
of social life, of economic life.

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And from the moment we control time,
we control people.

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GREECE ATHENS 270 BC

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Ancient civilizations
like the Babylonians or the Egyptians

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are therefore limited to the

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description of observable phenomena.

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It was not until the 5th century BC

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that scholars and Greek philosophers
engaged in a new stage

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in the manufacture of time.

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They will manage to materialize
the passing of time

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by inventing prodigious machines.

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In the alleys of central Athens,

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a tiny museum is dedicated
to the technologies of Ancient Greece.

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It is here that a former engineer
reconstructed one

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of the most significant inventions
of that era.

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The clepsydra, meaning “water thief”
in Greek,

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is the very first autonomous water clock.

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It is the work of a mechanical genius,
Ctesibius Alexandria.

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I started my research
in 1981.

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At the time, I was studying
at Polytechnic in Athens.

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I am a mechanical engineer.

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With the help of one of my teachers,

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I immersed myself in the technologies
of Ancient Greece.

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I looked for the sources
of these extraordinary inventions.

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And little by little, I started
to find solutions.

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The Ctesibius clock
is an extraordinary invention.

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It is the first hydraulic clock.

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Our main source of research
was inspired by the drawings of Vitruvius,

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a Roman architect,
who described the inventions of Ctesibius.

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This water clock is truly admirable,

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because it works with a gear system,

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based on a ratio of 1 to 365.

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It has rods, cogs and internal worm gears
that Vitruvius describes in detail.

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Ctesibius’s clepsydra consists of a system

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with 3 receptacles supplied
by a water source

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and fitted with a piston operating
with compressed air.

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A first of its kind.

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An ingenious cogwheel mechanism makes
it possible to indicate the exact time,

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whatever the length of the day of year.

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The remains of this brilliant invention
can be found in a little-known part

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of the Agora of Athens.

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This octagonal tower
indicated the direction

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of the winds and housed Ctesibius’s
monumental clock.

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The Tower of the winds is revolutionary

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because it shows the time to the citizens.

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In each of the building’s
eight sides there were solar clocks.

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So the people of Athens could see both
from the outside and the inside.

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From the outside when it was sunny,
and in general Athens is sunny.

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But also from the inside at night
and when there were clouds.

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Inside the Tower of the winds

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there was a system which was fed
by water from outside the building.

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So, it is a clock fed by a small source
called the clepsydra.

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It is a symbol of power.

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It shows the power of Athens,

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which has mastered time,

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and displays time to the Athenians,

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and its city’s visitors.

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To make public life uniform,

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the Greeks focused on time
and developed instruments available

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to all to situate themselves in time.

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Throughout antiquity, people lived
with unequal hours,

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which did not last 60 minutes as today.

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A day was split into 12 intervals.

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At the summer solstice, when the day
is longest, the hour counts 80 minutes.

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On the other hand, in winter,
as days are shorter,

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the hour is about 40 minutes.

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ITALY ROME 200 BC

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In the third century BC,

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the Romans didn’t take long to appropriate
the inventions of Greek culture.

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Heirs to the gnomons,

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sundials are the basis of ancient
Roman time keeping.

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Sundials appear everywhere in the city
and become common instruments.

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In the gardens of the Villa Borghese,
in Rome,

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one can still admire the inventions
of that time,

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when the hour intervenes
in many aspects of daily life,

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both private and public.

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These sundials have a double function.

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A social function, to indicate the time
to the citizens.

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But they are also prestigious objects.

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This sculpted one in Villa Borghese
is extraordinary.

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The owner wants to exhibit all
his scientific knowledge

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and the sculpture that goes around it.

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They’re not just scientific objects,
they are also art.

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And we show off our wealth and knowledge.

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And in general, we provide
them with a motto.

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Seneca had a beautiful one,

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"We have very little time,
we already lost a lot".

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And others are amusing like,
"It's later than you think".

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These mottos evoke the passage of time
from a philosophical

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and religious point of view.

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In Rome, during the time of Augustus
and Julius Caesar,

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there are plenty of sundials,

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and people are already complaining
about them.

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They were used to eating
when they were hungry.

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When sundials arrive, you have to eat
at noon on the dial.

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They’re already prisoners of time.

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Denis Savoie arrives
at the Piazza di Monteciterio.

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In front of the Italian parliament stands
an imposing monument,

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a vestige of Rome’s greatness
and of Roman scientific knowledge.

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We are in front of the obelisk
that Augustus brought back

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from the city of Heliopolis, in Egypt,

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to celebrate his victory over Egypt.

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And he places this obelisk on the field
of Mars in Rome,

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which will constitute a meridian.

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It is a gigantic gnomon

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which indicates both solar noon
and the date at the same time.

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This 22-meter-high obelisk measures
the lengthening

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or shortening of the days during the year.

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Archaeologists recently discovered
that this monument,

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00:18:41,201 --> 00:18:43,656
inaugurated 10 years before our era,

246
00:18:43,736 --> 00:18:46,096
was unique in its size in antiquity.

247
00:18:47,667 --> 00:18:51,996
Emperor Augustus placed the gigantic
obelisk on a vast square paved

248
00:18:52,076 --> 00:18:55,536
with marble, about 500 feet by 230 feet.

249
00:18:57,600 --> 00:19:00,616
Astronomical graduations were traced
on the ground,

250
00:19:00,696 --> 00:19:03,856
on the North-South axis,
with bronze inscriptions,

251
00:19:03,936 --> 00:19:05,750
a few of which have been found.

252
00:19:14,924 --> 00:19:16,816
It also serves as a calendar.

253
00:19:17,138 --> 00:19:19,856
Because for the Romans,
time is not just the hour,

254
00:19:19,936 --> 00:19:23,856
but also long-term time management
of days and months.

255
00:19:24,811 --> 00:19:26,865
And we must remember
that before Augustus,

256
00:19:26,945 --> 00:19:28,656
during Julius Caesar’s rule,

257
00:19:28,936 --> 00:19:31,896
they already had a calendar,
the Republican calendar,

258
00:19:31,976 --> 00:19:34,416
dating back to the 8th century BC.

259
00:19:34,976 --> 00:19:37,247
This calendar had the particularity that

260
00:19:37,328 --> 00:19:39,456
it was left to the favour of the pontiffs.

261
00:19:40,264 --> 00:19:41,561
And at the end of the year,

262
00:19:41,641 --> 00:19:44,728
they added a month or two to stay
in line with the seasons.

263
00:19:45,152 --> 00:19:49,456
But what happens quickly is this calendar
becomes a means of political corruption.

264
00:19:50,300 --> 00:19:53,589
Depending on whether the pontiffs
have friends or enemies in power,

265
00:19:53,669 --> 00:19:56,376
they lengthen or shorten the length
of the year.

266
00:19:57,526 --> 00:19:59,750
And it arrives at such a cacophony that

267
00:19:59,839 --> 00:20:01,576
when Julius Caesar comes to power,

268
00:20:01,823 --> 00:20:04,336
they celebrate the harvest in the spring.

269
00:20:09,401 --> 00:20:12,776
Caesar wants to bring some order
into the Roman agenda.

270
00:20:12,856 --> 00:20:14,683
The choices the Emperor makes

271
00:20:14,763 --> 00:20:18,016
are not without consequences
for our current calendar.

272
00:20:18,424 --> 00:20:21,696
He first decides that the year
begins on January 1st.

273
00:20:21,776 --> 00:20:26,136
He then designates new months according
to the names of the gods and goddesses,

274
00:20:26,339 --> 00:20:29,696
Januarius, for Janus, god of beginnings
and gates,

275
00:20:29,776 --> 00:20:32,336
becomes the month of January… or Junius,

276
00:20:32,416 --> 00:20:35,976
for Juno the goddess of family
becomes the month of June.

277
00:20:36,227 --> 00:20:38,579
The new calendar also makes references

278
00:20:38,659 --> 00:20:41,480
to Julius Caesar’s family
and his adopted son,

279
00:20:41,576 --> 00:20:44,936
with Julius and Augustus for the months
of July and August.

280
00:20:45,982 --> 00:20:48,976
The first thing Julius Caesar
does is hire Sausigene,

281
00:20:49,056 --> 00:20:51,496
an astronomer to reform this calendar,

282
00:20:51,576 --> 00:20:54,776
and then to bring the calendar back
in line with the seasons.

283
00:20:55,067 --> 00:20:57,536
We’ll have a year with 455 days,

284
00:20:57,616 --> 00:20:59,616
this is called “the year of confusion”.

285
00:20:59,696 --> 00:21:02,816
And he then established
what is called the Julian calendar,

286
00:21:03,180 --> 00:21:05,496
which has a leap year every 4 years.

287
00:21:05,576 --> 00:21:08,496
That dates from 45/46 BC.

288
00:21:10,782 --> 00:21:13,456
This is how César
created the longest year,

289
00:21:13,536 --> 00:21:15,696
a year of 15 months!

290
00:21:19,161 --> 00:21:22,574
After a flourishing ancient period
in the field of instruments

291
00:21:22,654 --> 00:21:23,656
for measuring time,

292
00:21:23,736 --> 00:21:27,868
the race for accuracy continues
considerably in the Muslim countries

293
00:21:27,948 --> 00:21:32,056
with immense progress in the fields
of mathematics, geometry or physics.

294
00:21:36,018 --> 00:21:39,296
But in Europe, in the Christian world,
this is not what will happen.

295
00:21:42,075 --> 00:21:43,285
FRANCE BOURGES 1424

296
00:21:44,603 --> 00:21:47,176
In the late Middle Ages
in the 13th century,

297
00:21:47,256 --> 00:21:52,056
a mechanical invention will influence
all humankind for ages to come.

298
00:22:01,652 --> 00:22:02,936
Preserved like a treasure,

299
00:22:03,016 --> 00:22:05,734
the astronomical clock
of Bourges cathedral

300
00:22:05,814 --> 00:22:07,757
is the work of Jean Fusoris,

301
00:22:07,837 --> 00:22:10,176
French astronomer and mathematician.

302
00:22:14,147 --> 00:22:18,896
Today, visitors to the cathedral
can admire an intricate mechanism,

303
00:22:18,976 --> 00:22:21,576
which not only tells the time,
rings the bells,

304
00:22:21,656 --> 00:22:25,096
but also indicates the cycles
of the Moon and the Sun.

305
00:22:38,296 --> 00:22:40,595
We’re inside Jean Fusoris' clock,

306
00:22:40,675 --> 00:22:43,536
and we can clearly see the foliot, here.

307
00:22:43,913 --> 00:22:47,240
This horizontal bar with the two masses
which balance it.

308
00:22:47,320 --> 00:22:50,376
Here’s the drive axis
with the two small pallets.

309
00:22:50,899 --> 00:22:53,416
And the escape wheel we see turning here.

310
00:22:53,617 --> 00:22:56,216
And the weight at the bottom
that drives it all.

311
00:22:57,288 --> 00:22:59,451
It’s extraordinary
because it is practically

312
00:22:59,531 --> 00:23:02,016
the only one which
is still in use in France.

313
00:23:06,655 --> 00:23:10,492
This new generation mechanical clock
has 3 essential parts.

314
00:23:12,720 --> 00:23:16,856
A weight, an escape wheel,
and a verge escapement.

315
00:23:17,142 --> 00:23:19,336
The weight causes the needle to rotate.

316
00:23:21,563 --> 00:23:23,938
The escape wheel
transmits the driving force

317
00:23:24,018 --> 00:23:25,215
of the weight to the cog.

318
00:23:27,728 --> 00:23:30,548
And the verge escapement,
coupled to the escape wheel,

319
00:23:30,629 --> 00:23:32,856
serves as a horizontal balance.

320
00:23:34,072 --> 00:23:37,313
These beats are the units
which give the fractions of time.

321
00:23:38,706 --> 00:23:42,213
This formidable technical innovation
triggered a great vogue

322
00:23:42,293 --> 00:23:44,816
for mechanical clocks in the 14th century,

323
00:23:44,896 --> 00:23:46,216
all over Europe.

324
00:23:48,779 --> 00:23:51,696
This system is really the beginning
of watchmaking.

325
00:23:52,128 --> 00:23:56,229
It is an absolute splendour.
And it will last until the 17th century

326
00:23:56,309 --> 00:23:59,416
with the invention of the pendulum clock
by Christian Huygens.

327
00:24:03,072 --> 00:24:04,838
FRANCE PARIS 1667

328
00:24:06,657 --> 00:24:09,376
Christian Huygens is a Dutch scientist

329
00:24:09,456 --> 00:24:12,164
who will put his genius
at the service of the Sun King.

330
00:24:12,666 --> 00:24:14,923
A member of the Academy of Sciences,

331
00:24:15,011 --> 00:24:19,976
the young man attended the construction
of the Paris Observatory in 1667.

332
00:24:20,056 --> 00:24:24,536
This institution was to become
a major centre of scientific conquest.

333
00:24:26,001 --> 00:24:28,096
We are in the Paris Observatory.

334
00:24:28,715 --> 00:24:31,496
It’s one of the benchmarks
of world time measurement.

335
00:24:32,244 --> 00:24:36,536
There are many in this race which
will add more precision in time keeping.

336
00:24:37,540 --> 00:24:39,336
And the instruments are built here,

337
00:24:39,416 --> 00:24:41,813
experiments are made, clocks are tested,

338
00:24:41,893 --> 00:24:42,976
reports are made.

339
00:24:43,056 --> 00:24:45,816
We are in the very centre
of time measurement.

340
00:24:49,123 --> 00:24:52,656
With Huygens, we have clocks
that we call “high precision”.

341
00:24:53,904 --> 00:24:57,942
Because Huygens was not only been able
to use the pendulum as a clock regulator,

342
00:24:58,373 --> 00:25:01,936
he was also able to maintain
this regularity over time.

343
00:25:05,466 --> 00:25:07,976
The principle of this technological
revolution

344
00:25:08,056 --> 00:25:10,456
is linked to two major innovations.

345
00:25:11,184 --> 00:25:12,536
The first is a pendulum

346
00:25:12,616 --> 00:25:16,856
which under the effect of gravity
makes a return trip once per second.

347
00:25:17,380 --> 00:25:18,936
This is its frequency.

348
00:25:19,325 --> 00:25:22,576
The second novelty
is the lever escapement system

349
00:25:22,656 --> 00:25:26,696
which allows the oscillations
of the pendulum to be counted precisely.

350
00:25:28,854 --> 00:25:31,536
The biggest problem
is constant isochronism.

351
00:25:31,960 --> 00:25:33,536
What does isochronism mean?

352
00:25:33,616 --> 00:25:37,536
Isos means "equal",
and "Chronos" means time.

353
00:25:38,163 --> 00:25:40,536
So, the question Huygens asked himself

354
00:25:40,617 --> 00:25:42,984
was how to make sure that between
the tick and tock,

355
00:25:43,109 --> 00:25:45,215
we always have one second,

356
00:25:45,515 --> 00:25:48,216
and that all ticks and tocks are equal?

357
00:25:58,159 --> 00:26:01,668
Christian Huygens seems to have
befriended Louis XIV.

358
00:26:02,289 --> 00:26:07,897
In 1673, he dedicated his last
work to him, on watchmaking mechanics.

359
00:26:10,606 --> 00:26:12,905
Invited to Versailles a few years earlier,

360
00:26:12,986 --> 00:26:16,471
Huygens presented the Sun King
with his latest invention.

361
00:26:16,659 --> 00:26:20,426
A clock driven by a pendulum,
whose beat seems eternal.

362
00:26:29,158 --> 00:26:32,631
He explained to the amazed court
that thanks to this pendulum,

363
00:26:32,769 --> 00:26:36,616
the timepiece only advances
or lags by 15 seconds a day.

364
00:26:41,859 --> 00:26:45,265
It is a veritable leap forward in the race
for precision.

365
00:26:51,971 --> 00:26:57,284
Huygens is convinced that we can determine
our longitudinal position with precision,

366
00:26:57,441 --> 00:26:59,334
using precise clocks.

367
00:27:05,055 --> 00:27:07,168
Galileo believed that a precision clock,

368
00:27:07,347 --> 00:27:10,107
or an instrument for measuring time
was an instrument...

369
00:27:10,188 --> 00:27:12,773
for accompanying astronomical observations

370
00:27:13,161 --> 00:27:16,924
and that the solution was in astronomical
observations.

371
00:27:17,866 --> 00:27:19,274
Huygens was convinced...

372
00:27:19,408 --> 00:27:22,479
that if he found a way to take time
keeping with him on a boat,

373
00:27:22,719 --> 00:27:25,679
he would solve the problem of determining
longitude.

374
00:27:29,703 --> 00:27:32,545
To find your exact bearings
on the Earth’s surface,

375
00:27:32,632 --> 00:27:34,551
you need to know two coordinates:

376
00:27:36,913 --> 00:27:41,732
latitude and longitude which determine
the angle between our position

377
00:27:41,830 --> 00:27:45,344
and a reference meridian like
that of Paris or Greenwich.

378
00:27:53,939 --> 00:27:58,336
For latitude, it is possible to locate
yourself in relation to the pole star,

379
00:27:58,438 --> 00:28:01,231
always fixed in the sky of the northern
hemisphere.

380
00:28:04,446 --> 00:28:08,666
But longitude requires comparing the time
on the meridian of origin,

381
00:28:09,040 --> 00:28:11,560
to that of the place
where we presently are.

382
00:28:14,753 --> 00:28:18,879
A difference of 4 minutes corresponds
to 1 degree of longitude,

383
00:28:18,960 --> 00:28:21,776
or about a hundred kilometres
on the equator.

384
00:28:30,331 --> 00:28:34,328
At the time, on-board clocks
did not withstand sea travel.

385
00:28:38,065 --> 00:28:40,905
Roll, pitch and dust disrupted them.

386
00:28:43,534 --> 00:28:47,447
Thus, navigators do not have a reliable
means on board

387
00:28:47,550 --> 00:28:50,044
to determine their longitudinal position.

388
00:28:53,469 --> 00:28:55,768
Despite several promising experiments,

389
00:28:55,943 --> 00:28:59,036
with Christian Huygens’ clocks on board
French navy ships,

390
00:28:59,164 --> 00:29:00,864
the 17th century ended...

391
00:29:01,179 --> 00:29:05,033
without finding a solution to the question
of measurement of longitude.

392
00:29:09,566 --> 00:29:13,497
For most scientists,
it even appears to be unanswerable.

393
00:29:16,358 --> 00:29:19,464
But the English have not yet said
their last word.

394
00:29:28,245 --> 00:29:31,469
ENGLAND LONDON 1730

395
00:29:47,054 --> 00:29:50,924
The scientific battle for longitudes
is being fought from Greenwich

396
00:29:51,004 --> 00:29:52,327
Observatory in London.

397
00:29:52,408 --> 00:29:55,526
It is on this hill that the famous
meridian was drawn.

398
00:29:55,607 --> 00:29:58,241
And that, in 1675, GMT,
Greenwich Mean Time,

399
00:29:58,321 --> 00:30:01,266
the average time of Greenwich,
was established.

400
00:30:01,496 --> 00:30:05,141
It is also here that we maintain
the memory of a drama that

401
00:30:05,221 --> 00:30:07,786
turned the history of time upside down.

402
00:30:08,015 --> 00:30:12,723
One of Britain’s greatest naval disasters
took place in 1707 on the 22nd of October.

403
00:30:13,288 --> 00:30:16,288
Sir Cloudesley Shovell, who had been
stationed in the Mediterranean,

404
00:30:16,375 --> 00:30:22,106
was sailing back to England and lost 4
of his ships on the Islands of Scilly.

405
00:30:22,256 --> 00:30:26,717
Including himself, approximately
1,400 to 2,000 lives were lost.

406
00:30:31,040 --> 00:30:32,745
The charts were incorrect,

407
00:30:32,826 --> 00:30:35,539
their navigational calculations
were incorrect.

408
00:30:35,659 --> 00:30:37,633
The latitude had not been correctly
observed.

409
00:30:37,789 --> 00:30:40,429
And the islands were positioned 15 miles

410
00:30:40,576 --> 00:30:43,002
northwards on the charts
from where they actually were.

411
00:30:43,257 --> 00:30:45,131
This brought to the British public,

412
00:30:45,280 --> 00:30:48,865
the enormous problems
that sailors faced at sea.

413
00:30:52,639 --> 00:30:56,140
Following this maritime disaster, in 1714,

414
00:30:56,267 --> 00:30:57,579
the British Admiralty

415
00:30:57,660 --> 00:31:01,099
launched a competition
for scientists and watchmakers,

416
00:31:01,180 --> 00:31:03,778
so that they could develop
the first marine clock,

417
00:31:03,885 --> 00:31:07,304
capable of giving the correct longitude
without error.

418
00:31:10,699 --> 00:31:12,117
The reward was in a tier system,

419
00:31:12,198 --> 00:31:16,286
so the more accurate your longitude
determinations were by your methods,

420
00:31:16,486 --> 00:31:19,260
the more money you would get
for your efforts.

421
00:31:19,475 --> 00:31:23,081
The biggest reward the board
offered was 20,000 pounds,

422
00:31:23,369 --> 00:31:26,689
if you could determine the longitude
to within half a degree,

423
00:31:26,942 --> 00:31:29,508
or within 30 geographical miles.

424
00:31:38,183 --> 00:31:42,604
In 1730, a genius clock maker will take
up the challenge.

425
00:31:45,373 --> 00:31:49,033
After inventing high-performance wooden
mechanisms for the period,

426
00:31:49,321 --> 00:31:51,371
John Harrison dedicated himself

427
00:31:51,458 --> 00:31:55,193
to the design of a perfectly precise
marine chronometer.

428
00:31:57,090 --> 00:32:01,450
The famous navigator James Cook
would later be the first to experience.

429
00:32:01,531 --> 00:32:04,820
Harrison's timepieces on his travels
around the world.

430
00:32:07,352 --> 00:32:09,551
The greatest challenges
for a clock to work,

431
00:32:09,632 --> 00:32:11,046
or a marine time keeper,

432
00:32:11,127 --> 00:32:14,424
were that it had to be able to deal
the movement of the ship,

433
00:32:14,918 --> 00:32:18,218
it had to be able to deal with extreme
temperatures variations.

434
00:32:19,696 --> 00:32:22,113
There was also the problem of oil.

435
00:32:22,238 --> 00:32:25,538
Because any clock that is going to run
for a long period of time,

436
00:32:25,682 --> 00:32:28,353
the oil would prevent
it from keeping its accuracy.

437
00:32:41,285 --> 00:32:45,344
Harrison's designs are based on the theory
on the pendulum clock.

438
00:32:45,653 --> 00:32:48,579
The power is the main spring.

439
00:32:48,708 --> 00:32:52,090
He devised a self-maintaining power system

440
00:32:52,171 --> 00:32:54,389
so the clocks wouldn’t run
down when they were wound up.

441
00:32:54,666 --> 00:32:56,717
That’s one of Harrison's great
inventions.

442
00:32:57,279 --> 00:32:59,198
The other thing that
Harrison did is that

443
00:32:59,279 --> 00:33:01,291
he made two bar-bell constructions

444
00:33:01,565 --> 00:33:03,485
that work simultaneously.

445
00:33:03,566 --> 00:33:05,910
So any movement would be counter-acted
by a movement...

446
00:33:05,990 --> 00:33:07,253
on the opposite end.

447
00:33:07,334 --> 00:33:09,369
They were connected by springs...

448
00:33:10,013 --> 00:33:12,899
which Harrison called
"artificial gravity"

449
00:33:16,512 --> 00:33:18,226
In 1736,

450
00:33:18,307 --> 00:33:22,096
John Harrison embarks on an English
navy ship with his sea clock,

451
00:33:22,177 --> 00:33:23,686
for a crossing to Lisbon.

452
00:33:25,806 --> 00:33:28,939
This trip is a test for the Commission
of longitudes.

453
00:33:31,860 --> 00:33:36,260
But his chronometer reacted very
badly in the difficult conditions at sea.

454
00:33:39,132 --> 00:33:43,032
It was impossible for him to obtain
reliable calculations,

455
00:33:43,120 --> 00:33:45,635
which would have allowed
the ship to determine its position

456
00:33:45,716 --> 00:33:47,122
on the nautical charts.

457
00:33:48,175 --> 00:33:51,148
Once in Portugal however,
the clock maker doesn’t give up.

458
00:33:51,735 --> 00:33:54,475
He knows his invention needs
some fine tuning.

459
00:34:01,861 --> 00:34:03,681
On the return trip to Portsmouth,

460
00:34:03,762 --> 00:34:07,145
Harrison finally calculates the exact
position of the ship.

461
00:34:11,574 --> 00:34:15,993
The success of his trip earned
him a scholarship of 500 pounds.

462
00:34:17,668 --> 00:34:19,707
Having a longitude method
wasn’t going to give

463
00:34:19,787 --> 00:34:21,267
them an edge over other countries.

464
00:34:21,348 --> 00:34:22,467
They already had that.

465
00:34:22,911 --> 00:34:26,070
It was just quicker, cheaper,
more efficient.

466
00:34:26,342 --> 00:34:27,999
It was an economic advantage,

467
00:34:28,080 --> 00:34:30,186
it would give them an advantage in trade.

468
00:34:31,608 --> 00:34:33,302
Over the next 30 years,

469
00:34:33,483 --> 00:34:36,543
Harrison will not stop perfecting
his clock.

470
00:34:40,187 --> 00:34:41,903
FRANCE PARIS 1760

471
00:35:02,928 --> 00:35:05,948
John Harrison won the Royal
Admiralty Award.

472
00:35:06,546 --> 00:35:09,266
But he was followed in Paris by a French
clock maker,

473
00:35:09,419 --> 00:35:12,953
Ferdinand Berthoud, who managed
to design his own chronometer.

474
00:35:16,166 --> 00:35:19,713
Thus, determining a geographical
position on land or

475
00:35:19,794 --> 00:35:22,706
at sea is inseparable
from the measurement of time.

476
00:35:23,473 --> 00:35:27,742
The more precise this measurement,
the more accurate our positioning will be.

477
00:35:28,724 --> 00:35:30,857
But to achieve this level of accuracy,

478
00:35:30,983 --> 00:35:34,230
it is still necessary to benefit
from a common timescale.

479
00:35:34,311 --> 00:35:36,343
A universal temporal language.

480
00:35:36,471 --> 00:35:40,531
In other words, the same time for all,
standard and unified.

481
00:35:40,756 --> 00:35:42,443
In the early 19th century,

482
00:35:42,597 --> 00:35:45,113
while the world still lives
according to solar time,

483
00:35:45,276 --> 00:35:49,232
the Industrial Revolution radically
changes our perception of time.

484
00:35:49,404 --> 00:35:50,874
With the invention of the railway,

485
00:35:50,955 --> 00:35:53,677
engineers will have to overcome a major
obstacle.

486
00:35:53,788 --> 00:35:57,401
How to carry travellers on different time
scales across countries.

487
00:36:01,640 --> 00:36:06,408
There are church sundials, station clocks,
hours of astronomical observatories.

488
00:36:06,569 --> 00:36:08,822
But which schedule will be the standard?

489
00:36:11,359 --> 00:36:13,887
Travellers never stop adjusting
their watches.

490
00:36:14,158 --> 00:36:17,864
As for locomotive engineers,
despite their hourly indicators,

491
00:36:17,945 --> 00:36:22,182
they are never immune to a delay
due to a breakdown or an unforeseen event,

492
00:36:22,311 --> 00:36:24,690
which always leads to more confusion.

493
00:36:28,671 --> 00:36:29,830
In the United States,

494
00:36:29,911 --> 00:36:34,624
a passenger crossing the country must
reset his watch 75 times.

495
00:36:36,026 --> 00:36:38,273
One day in August 1883,

496
00:36:38,368 --> 00:36:41,841
a train left Providence City on the East
Coast, travelling north.

497
00:36:43,063 --> 00:36:46,112
At the same time,
at the other end of the railway line,

498
00:36:46,193 --> 00:36:48,493
a train leaves a station, heading south.

499
00:36:51,179 --> 00:36:54,566
The 2 locomotives are going at full
speed on a single track.

500
00:36:54,647 --> 00:36:56,714
The engineers have the same schedules,

501
00:36:56,854 --> 00:36:59,607
but do not have the same
time on their watch.

502
00:37:07,894 --> 00:37:10,300
In a blind curve, the two trains collide,

503
00:37:10,468 --> 00:37:12,775
creating a twisted tragedy of metal.

504
00:37:13,792 --> 00:37:17,798
The toll is terrible:
14 dead and 17 injured.

505
00:37:19,832 --> 00:37:23,143
After numerous accidents of this kind
all over the world,

506
00:37:23,466 --> 00:37:26,486
synchronizing railway clocks
becomes a priority.

507
00:37:35,480 --> 00:37:38,378
In 1884, after heated exchanges,

508
00:37:38,499 --> 00:37:41,359
particularly between France
and the United States,

509
00:37:41,451 --> 00:37:44,438
the Washington conference chose
the Greenwich meridian

510
00:37:44,533 --> 00:37:47,779
as a reference for the creation
of a system of time zones.

511
00:37:48,341 --> 00:37:50,114
It is the one we know today.

512
00:37:58,831 --> 00:37:59,958
Paradoxically,

513
00:38:00,099 --> 00:38:02,749
it’s at this moment
that our conception of a time

514
00:38:02,838 --> 00:38:04,587
which passes in an identical way

515
00:38:04,667 --> 00:38:07,573
for everyone will be radically
called into question.

516
00:38:11,112 --> 00:38:15,719
Astrophysicist Pacôme Delva is an heir
to this revolution in Switzerland,

517
00:38:15,800 --> 00:38:18,429
more than 100 years ago by modern physics,

518
00:38:18,516 --> 00:38:21,989
when Albert Einstein published his theory
of relativity.

519
00:38:26,210 --> 00:38:28,223
It's funny, because during that period,

520
00:38:28,438 --> 00:38:31,057
we were trying to harmonize
the same time for everyone,

521
00:38:31,362 --> 00:38:33,836
for France’s railway stations
and around the world,

522
00:38:34,862 --> 00:38:40,768
Einstein with Relativity showed us
that absolute rigid time does not exist.

523
00:38:41,406 --> 00:38:44,506
And that's what Relativity
actually shows us.

524
00:38:45,079 --> 00:38:46,979
That everyone has their own time.

525
00:38:47,632 --> 00:38:49,405
And so it's paradoxical.

526
00:38:50,070 --> 00:38:54,117
Because today, we have this illusion
that we all have the same time.

527
00:38:54,266 --> 00:38:58,077
But in fact, it's virtual,
it's fabricated.

528
00:39:01,646 --> 00:39:03,489
SWITZERLAND BERN 1905

529
00:39:07,697 --> 00:39:11,017
This cyclist has the impression
that the city is passing by her,

530
00:39:11,425 --> 00:39:13,171
but we can just as well say that

531
00:39:13,252 --> 00:39:16,875
the motionless spectators in this scene
have the impression that

532
00:39:16,956 --> 00:39:19,012
it is the bike that’s scrolling by.

533
00:39:20,869 --> 00:39:25,035
These 2 equivalent perceptions describe
the principle of relativity.

534
00:39:29,129 --> 00:39:30,189
Likewise,

535
00:39:30,287 --> 00:39:33,734
Albert Einstein declares
that this impression of passing time

536
00:39:33,815 --> 00:39:36,981
is explained by our displacement in space
time.

537
00:39:40,010 --> 00:39:43,337
In order to explain
the genesis of this innovative theory,

538
00:39:43,418 --> 00:39:45,500
Pacome Delva goes to the places that

539
00:39:45,581 --> 00:39:49,058
served as young Einstein’s
laboratory in a manner of speaking.

540
00:39:53,618 --> 00:39:56,086
So, you have to imagine it is 1905,

541
00:39:56,211 --> 00:39:59,091
Albert Einstein lives just a little
below here.

542
00:39:59,363 --> 00:40:01,234
To go to work at the Patent Office

543
00:40:01,315 --> 00:40:02,916
which is a little further north

544
00:40:03,107 --> 00:40:06,214
he always passed by here
and saw the Clock Tower.

545
00:40:06,352 --> 00:40:08,679
And so he was confronted with certain
questions,

546
00:40:08,759 --> 00:40:11,425
of time, the nature of time, etcetera...

547
00:40:17,058 --> 00:40:18,214
In 1905,

548
00:40:18,336 --> 00:40:20,900
the public clocks in Bern
were electrically

549
00:40:20,981 --> 00:40:23,050
coordinated for 15 years already.

550
00:40:23,768 --> 00:40:26,221
Albert Einstein has been studying
the patents

551
00:40:26,318 --> 00:40:29,046
relating to time synchronization
for three years

552
00:40:31,377 --> 00:40:34,231
and then one day,
the young man has a revelation:

553
00:40:34,607 --> 00:40:37,894
Absolute simultaneity does not exist.

554
00:40:39,153 --> 00:40:43,219
Two simultaneous events for one
observer are not necessarily

555
00:40:43,300 --> 00:40:45,119
the same for another observer.

556
00:40:48,453 --> 00:40:50,032
Those who preceded us or...

557
00:40:50,252 --> 00:40:53,792
those who preceded Albert
Einstein have all contributed elements.

558
00:40:54,972 --> 00:40:57,645
And for me it is really a common work,

559
00:40:57,726 --> 00:41:01,292
where sometimes, a genius like Einstein
will come to add a touch,

560
00:41:02,122 --> 00:41:05,869
and he’ll succeed with the synthesis
of various theories of his era.

561
00:41:09,366 --> 00:41:11,866
And he makes a leap in understanding,

562
00:41:11,947 --> 00:41:14,314
while other people cling to older ideas,

563
00:41:14,498 --> 00:41:17,938
staying in tradition,
they can't make that conceptual leap.

564
00:41:19,444 --> 00:41:21,595
But Einstein managed to do it,

565
00:41:22,768 --> 00:41:27,053
like Kepler did before him, like Galileo,
and other greats.

566
00:41:28,306 --> 00:41:30,933
They managed to create something new.

567
00:41:38,933 --> 00:41:43,422
Like Galileo who describes that all bodies
fall at the same speed in a vacuum,

568
00:41:43,549 --> 00:41:44,856
whatever their mass,

569
00:41:45,130 --> 00:41:48,284
physics sometimes progresses against
common sense.

570
00:41:50,600 --> 00:41:54,480
Einstein's theory of relativity is no
exception to this rule.

571
00:41:57,006 --> 00:41:58,125
Albert Einstein

572
00:41:58,214 --> 00:42:01,077
Albert Einstein made many thought
experiments.

573
00:42:01,257 --> 00:42:03,722
We can also do a thought experiment,
like Einstein.

574
00:42:05,451 --> 00:42:08,268
Suppose I ask a friend to come
with me to Bern.

575
00:42:09,166 --> 00:42:10,826
We take the train in Paris,

576
00:42:10,959 --> 00:42:12,619
but we don’t take the same train.

577
00:42:14,295 --> 00:42:15,989
I'm take a high-speed train,

578
00:42:16,203 --> 00:42:18,343
which will arrive in Bern fairly quickly,

579
00:42:18,523 --> 00:42:19,844
as quickly as possible.

580
00:42:20,194 --> 00:42:23,710
My friend takes a much slower train,
it will arrive later.

581
00:42:25,178 --> 00:42:28,564
In Paris,
we take two very precise watches.

582
00:42:29,425 --> 00:42:31,818
Like those we make today
with atomic clocks.

583
00:42:32,310 --> 00:42:33,843
And we synchronize them.

584
00:42:35,108 --> 00:42:38,448
We put the same time on each
watch in Paris before leaving.

585
00:42:39,457 --> 00:42:44,123
I arrive much faster than him in Bern,
and once in Bern I wait for him.

586
00:42:45,432 --> 00:42:47,797
I wait for his train which goes
much slower.

587
00:42:48,975 --> 00:42:52,304
And once it arrives,
we compare our watches.

588
00:42:53,574 --> 00:42:56,663
Well, the time that elapsed between
these two events,

589
00:42:56,915 --> 00:42:58,448
the departure from Paris when

590
00:42:58,529 --> 00:43:00,395
I synchronized my watch with my friend

591
00:43:00,623 --> 00:43:02,691
and the arrival of my friend in Bern.

592
00:43:02,946 --> 00:43:06,486
When we re-compare our watches
between these two events

593
00:43:06,591 --> 00:43:08,263
we don’t have the same durations...

594
00:43:08,592 --> 00:43:11,645
because our two trains did not go
at the same speed.

595
00:43:12,267 --> 00:43:15,731
The difference on the watches
will be a fraction of a nanosecond.

596
00:43:19,923 --> 00:43:23,117
With Einstein,
it’s the end of the great universal beat

597
00:43:23,197 --> 00:43:25,433
translated by the ticking of clocks.

598
00:43:27,631 --> 00:43:31,497
Physicists will gradually take
the reins to impose a conventional

599
00:43:31,624 --> 00:43:34,638
and purely manufactured time
with full knowledge.

600
00:43:44,317 --> 00:43:48,483
In a world launched headlong
into the quest for ever greater precision,

601
00:43:48,719 --> 00:43:50,572
physicists in Einstein's wake

602
00:43:50,800 --> 00:43:54,100
will soon rethink our machines
to manufacture time.

603
00:44:00,279 --> 00:44:01,838
At the Paris Observatory,

604
00:44:01,918 --> 00:44:05,086
you can still contemplate the mechanical
instruments that

605
00:44:05,166 --> 00:44:06,673
revolutionized their time.

606
00:44:10,983 --> 00:44:13,086
Protected under their glass bells,

607
00:44:13,296 --> 00:44:16,156
here are the ancestors
of our quartz clocks.

608
00:44:19,299 --> 00:44:21,146
From the 1930s,

609
00:44:21,260 --> 00:44:23,466
we will have extremely precise clocks.

610
00:44:23,634 --> 00:44:26,481
An astronomer who worked here,
Nicolas Stoiko,

611
00:44:26,848 --> 00:44:28,682
will notice that there is a drift between

612
00:44:28,763 --> 00:44:31,137
the moment of a star’s
passage to the meridian,

613
00:44:31,533 --> 00:44:33,069
and the time given by the clock.

614
00:44:33,329 --> 00:44:35,551
These are very precise pendulum clocks

615
00:44:35,899 --> 00:44:37,784
and compared to the time given by the

616
00:44:37,865 --> 00:44:39,968
quartz clock at the Berlin Observatory,

617
00:44:40,322 --> 00:44:43,677
we will find that the Earth seems
to slow down in spring

618
00:44:43,758 --> 00:44:45,250
and accelerate in autumn.

619
00:44:46,054 --> 00:44:48,867
And he comes to understand
that this slowing down,

620
00:44:49,075 --> 00:44:51,408
and acceleration of the Earth's rotation,

621
00:44:51,736 --> 00:44:53,583
is due to the trade winds.

622
00:44:54,442 --> 00:44:58,216
And so, it dealt a fatal blow
at the end of the 1950s,

623
00:44:58,404 --> 00:45:00,004
to the standard of time.

624
00:45:01,177 --> 00:45:06,236
From now on, astronomers will lose time
management to the benefit of physicists.

625
00:45:10,017 --> 00:45:11,994
FRANCE PARIS 1967

626
00:45:12,832 --> 00:45:15,492
By searching for what is most
regular in nature,

627
00:45:15,666 --> 00:45:18,013
the movement of an electron in an atom,

628
00:45:18,394 --> 00:45:22,088
scientists invent the era
of the measurement of atomic time.

629
00:45:28,780 --> 00:45:32,069
It is in one of these
ancient astronomical domes

630
00:45:32,150 --> 00:45:36,004
that one of the most secret laboratories
of the Paris Observatory is hidden.

631
00:45:41,134 --> 00:45:44,101
Astrophysicist Pacôme Delva and his teams

632
00:45:44,182 --> 00:45:48,513
monitor the proper functioning of one
of the 5 atomic fountains in France.

633
00:45:53,671 --> 00:45:57,390
This type of clock, which produces
our official universal time,

634
00:45:57,566 --> 00:46:00,533
is based on the vibration
of the cesium atom.

635
00:46:10,935 --> 00:46:14,275
That's the Cesium cell,
with one gram of cesium.

636
00:46:14,656 --> 00:46:18,423
From this atom,
we will define what is one second.

637
00:46:24,742 --> 00:46:27,829
When an atom is bombarded with energy,
it vibrates.

638
00:46:34,012 --> 00:46:37,991
It emits more than 9 billion magnetic
pulses per second.

639
00:46:40,731 --> 00:46:43,378
Each time one arrives at the precise
number of

640
00:46:43,459 --> 00:46:49,404
9,192,631,770 beats,

641
00:46:49,513 --> 00:46:51,353
one second has elapsed.

642
00:46:52,432 --> 00:46:55,879
So, the seconds follow each other
in an infinite manner.

643
00:47:01,658 --> 00:47:03,698
When we say that this clock is exact,

644
00:47:03,786 --> 00:47:05,499
it means that we can certify that

645
00:47:05,580 --> 00:47:08,566
the frequency we get today
will be the same as next year,

646
00:47:08,848 --> 00:47:11,661
or in 10 years, or in 100 years.

647
00:47:15,319 --> 00:47:18,454
Today, the Paris Observatory is not only
responsible

648
00:47:18,534 --> 00:47:20,486
for creating French legal time.

649
00:47:20,728 --> 00:47:23,048
Its mission is also to distribute it.

650
00:47:24,449 --> 00:47:27,129
This takes place in an ultra
protected room,

651
00:47:27,217 --> 00:47:30,946
where scientists watch over
our time 24 hours a day.

652
00:47:34,406 --> 00:47:39,903
At the fourth signal
it will be 21 hours 51 minutes.

653
00:47:40,758 --> 00:47:44,726
Beep. Beep. Beep. Beep.

654
00:47:52,749 --> 00:47:55,536
We are in the National Time
Reference room,

655
00:47:56,377 --> 00:47:59,427
where French legal time is made
from the signals of the clocks

656
00:47:59,508 --> 00:48:00,597
in the laboratory.

657
00:48:02,679 --> 00:48:07,013
We are going to synthesize French legal
time with all these machines.

658
00:48:07,774 --> 00:48:12,041
Then we compare this legal time to other
times in other countries.

659
00:48:13,592 --> 00:48:16,933
And from all these times
we will synthesize a global time,

660
00:48:17,292 --> 00:48:18,744
which is called UTC.

661
00:48:19,332 --> 00:48:22,292
And from this UTC
which will be referenced in Greenwich,

662
00:48:22,654 --> 00:48:27,041
we will add a certain number of hours
depending on the time zone where we are.

663
00:48:27,805 --> 00:48:30,032
When a second passes here on this clock,

664
00:48:30,248 --> 00:48:34,288
it is the same second at the same time
which passes in the United States,

665
00:48:34,646 --> 00:48:37,880
Japan, China, Russia, etcetera.

666
00:48:55,180 --> 00:49:00,041
Even a very precise clock is not enough
to establish a reference time.

667
00:49:03,398 --> 00:49:07,392
This is why this time-broadcasting
room is linked with other clocks

668
00:49:07,473 --> 00:49:10,736
located abroad or in space,
on board a satellite.

669
00:49:17,726 --> 00:49:21,723
These two antennas here
send an electromagnetic signal into space,

670
00:49:21,997 --> 00:49:24,150
towards a geostationary satellite,

671
00:49:24,392 --> 00:49:26,585
meaning it remains fixed in the sky.

672
00:49:26,819 --> 00:49:30,488
And from these comparisons...
we are going to create a common time

673
00:49:30,710 --> 00:49:32,270
that will be the same for everyone,

674
00:49:32,554 --> 00:49:34,794
on all continents, in all countries.

675
00:49:38,153 --> 00:49:40,119
Once it was on-board ships,

676
00:49:40,750 --> 00:49:43,316
nowadays clocks navigate in space.

677
00:49:58,573 --> 00:50:00,200
The acceleration of time

678
00:50:00,281 --> 00:50:03,838
that we sometimes feel is thus
the consequence of a fabrication

679
00:50:03,918 --> 00:50:05,444
of the same hour for all.

680
00:50:07,733 --> 00:50:11,407
A conventional, synchronized
and increasingly precise time.

681
00:50:14,026 --> 00:50:16,754
This time made by ultra-powerful
computers

682
00:50:16,835 --> 00:50:21,118
has even become the key for all
the applications in a digital world.

683
00:50:24,783 --> 00:50:27,050
Whether it's our satellite-guided trips,

684
00:50:27,366 --> 00:50:31,860
our telecommunications which use ever
more data on synchronized networks,

685
00:50:32,219 --> 00:50:34,136
or our banking transactions for

686
00:50:34,223 --> 00:50:36,576
which every millisecond is worth millions.

687
00:50:38,391 --> 00:50:40,334
Our interconnected world is now

688
00:50:40,415 --> 00:50:43,958
based on clocks that measure
times ever more precisely.

689
00:50:45,093 --> 00:50:48,866
With enormous industrial and economic
challenges as a result.

690
00:50:50,911 --> 00:50:55,224
We have become dependent, even slaves,
to these new temporal norms.

691
00:50:59,598 --> 00:51:03,119
"Veritas filia temporis"
The truth, daughter of time.

692
00:51:03,281 --> 00:51:05,820
And to understand today's astronomy,
today's challenges,

693
00:51:05,901 --> 00:51:07,474
you have to go back to the past

694
00:51:07,716 --> 00:51:11,576
and it's astonishing that at the time
of the atomic clock and the GPS,

695
00:51:11,657 --> 00:51:15,149
we can never forget that we are the heirs
of all these astronomers...

696
00:51:15,305 --> 00:51:18,825
and that our current division of time
stems from human observations...

697
00:51:19,191 --> 00:51:20,771
and from mathematical theories.

698
00:51:21,088 --> 00:51:24,500
Understanding ancient times helps
shed light on today's science...

699
00:51:24,720 --> 00:51:26,033
and modern astronomy.

700
00:51:31,279 --> 00:51:33,886
From now on, with every passing second,

701
00:51:34,140 --> 00:51:35,761
we remember the geniuses

702
00:51:35,842 --> 00:51:39,787
who tried to unravel one of the greatest
mysteries of our existence.

703
00:51:40,415 --> 00:51:42,770
Einstein, Huygens, Galileo,

704
00:51:42,897 --> 00:51:44,988
Fusoris or even Ctesibius,

705
00:51:45,109 --> 00:51:48,175
they all in their own way shaped
the temporal language

706
00:51:48,256 --> 00:51:50,461
that brings us together today.