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Today, on Impossible Engineering,
China's biggest construction.
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One breaks the sky. Look at this super
power.
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The other extends beyond them. It can
pick up radio waves from billions of
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years away.
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Relying on pioneering innovations of the
past.
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Believe it or not, these are sound
mirrors.
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It took revolutionary engineering to
make the impossible possible.
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Since the dawn of time, humanity has
sought to unravel the mysteries of the
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universe. And in Guizhou province in
southwest China is a massive instrument
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that will further this quest.
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Tucked into a natural basin sits one of
the world's newest and most advanced
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space exploration devices.
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The 500 -meter Aperture Spherical Radio
Telescope, or FAST for short, is the
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largest and most sensitive single -dish
radio telescope in the world.
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It can pick up radio waves from billions
of light -years away.
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This massive 1 ,600 -foot diameter
antenna consists of a spider's web of 10
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steel cables, weighing nearly 1 ,800
tons.
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These support a sprawling 4 ,450
triangular panels, which form the dish
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And at the center, suspended from six
330 -foot high towers, hangs a 33 -ton
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receiver cabin.
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This incredible device collects data
from billions of light years away.
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This is the most amazing telescope in
the world.
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When we propose such a big telescope,
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nobody believes this big dish can be
built.
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The first problem engineers had when
constructing this thing is its sheer
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Fast is vast.
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So how can fast engineers build a
receiving dish of such epic proportions?
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This would be impossible without
history's greatest innovators.
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During America's post -war housing
shortage, architect Richard Buckminster
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Fuller bucked the traditional house.
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He developed the geodesic dome house.
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The Eden Project in Cornwall, England,
uses the geodesic concept on a massive
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scale to house plants from different
climates, including the tropics.
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Measuring 55 metres high, 100 metres
wide and 200 metres long, surrounding an
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area the size of 34 football pitches,
the rainforest biome is actually large
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enough to house the Tower of London.
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So how can a geodesic dome cover such a
vast amount of space?
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The real strength of Bolo's design was
that it was made with a series of
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triangles. Now the triangle, with its
fixed angles, is actually the strongest
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two -dimensional shape. Now I want to
show you exactly how this works by
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building one of these using only these.
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As I'm joining the triangles together,
they begin to form the shell of my
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structure, and the rigidity of each
triangle begins to form a tremendous
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strength.
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It's only when the final piece gets
added that the strength comes together.
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The bigger the dome gets, the stronger
it becomes.
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The only human -made structure to do
such a thing.
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It's very strong.
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So we see, Fuller's design definitely
works, just like the biomes behind me.
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Oh, amazing.
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Even more incredibly, when a sphere's
diameter is doubled, its surface area
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quadruples, creating eight times the
volume with very little surface area.
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This results in less materials and less
expensive homes.
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FAST's engineers are supersizing
Fuller's geodesic dome concept and
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on its head.
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Workers construct a one -mile -long
steel girder ring, forming the outer
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perimeter of the dish.
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Six 300 -foot -high towers surround it
and support a 33 -ton feed cabin.
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This houses the all -important receiver,
designed to capture even the faintest
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of galactic radio waves.
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So, in order to build such a giant
spherical reflector, a GeoDC
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triangular design is the best choice.
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After just five years of construction,
on July 3rd, 2016, the engineers lowered
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the last aluminum triangular panel into
place.
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is massive and that's ideal for
collecting those weak radio signals from
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billions of light years across the
universe.
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But it also presents engineers with a
big problem.
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Fast is so huge it has to be fixed to
the ground.
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Smaller radio telescopes have a receiver
fixed at the center of the dish to
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collect reflected radio waves.
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The dish rotates to point at the exact
area under observation.
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But the FAST dish is too enormous to do
that.
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As you can see from this rather nifty
little scale model, you can't just tilt
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the whole landscape to point fast at a
particular galaxy you might be
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in studying.
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So how do you make a telescope the size
of FAST point at different places in the
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sky?
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To resolve this, the team must draw on
history's greatest innovations.
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They find inspiration in these
monolithic structures, which once
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shorelines of Great Britain.
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Believe it or not, these are sound
mirrors.
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During the First World War, pioneering
acoustic physicist William Sansom Tucker
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designed these sound mirrors not to see,
but to hear approaching enemy aircraft.
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Here at Denj is some of the finest
examples of Tucker's work, and they're
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slightly different size and have
different structures.
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They're all based on a curved surface
known as a paraboloid.
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Sound waves hit a parabolic reflector at
different places. When those reflected
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rays meet at the focal point, the sound
amplifies.
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I'm going to attempt to recreate an
early warning scenario.
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So I'm going to place this microphone at
the focal point.
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So about there.
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And all the sound waves are going to
bounce off that reflector and be
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by that microphone.
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And that's represented by the blue curve
here. And the red trace is a control
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microphone that's placed off to one
side. The curves are the same.
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I can't really see any difference.
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But as aircraft approach from many miles
away, the parabolic sound mirrors let
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sound technicians hear the engines in
time to alert air defenses.
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So I can start to hear something.
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I can definitely hear a plane propeller.
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So I can definitely see that the blue
curve is above the red one in this
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region here.
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And historically, we could use these
sound mirrors to detect airplanes about
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or 20 miles away.
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To detect radio waves from different
areas in the sky without moving the
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telescope, FAST engineers are
revolutionizing the concept of multiple
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sound mirrors.
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with a single but dynamic 1 ,600 -foot
diameter dish.
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From down here, you can really see
what's unique about FAST.
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It uses these actuators to distort the
dish.
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They use 2 ,000 of these actuators to
pull that dish down into that perfect
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parabolic shape to get the sharpest
possible images of the sky.
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This system of actuators lets
astronomers point each individual panel
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area of the sky they wish, transforming
this big, apparently static dish into a
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dynamic moving reflector.
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That is the sound of this actuator
starting up, and believe it or not, it
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actually is moving very, very slowly,
about a millimeter every second.
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So rather than just looking straight up,
FAST can actually scan a region 40
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degrees either side of that so -called
zenith.
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This really is an incredibly innovative
solution they come up with here at FAST.
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But distorting the dish into a
paraboloid is just the first step toward
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unveiling the mysteries of the universe.
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To make the most powerful radio
telescope on Earth, engineers must look
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past. Oh, my God.
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I just took off an airplane.
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To create more impossible engineering.
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In China, engineers have created the
country's biggest radio telescope.
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And it's the most powerful terrestrial
tool in space exploration, the FAST
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telescope.
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Engineers can alter FAST's enormous
parabolic dish surface to collect radio
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waves from different areas of the sky.
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But as the reflectors change angles, the
central focal point also changes.
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This is the sensor cabin, and it's right
at the heart of FAST.
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Now, in order to track a galaxy moving
across the sky, you're going to have to
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keep moving this to keep it in exactly
the right spot to look at the object
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you're interested in.
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So, how do you move a 33 -ton receiver
cabin dangling around 300 feet high and
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still capture radio waves with pinpoint
accuracy?
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To accomplish the impossible, fast
engineers must look to the past.
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They turned to an innovation from 1964
when American engineer Klaus Kappel was
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developing a realistic flight simulator.
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And here they are.
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These cutting -edge machines are some of
the most advanced flight sims available
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today.
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You can see here there are six hydraulic
jacks or actuators. They're positioned
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in pairs and move independently from
each other.
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Using these hydraulic jacks, Capel
created what's called a motion platform,
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forerunner to modern flight simulators.
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Oh, my God.
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I just took off an airplane.
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I can't see. What do you do?
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Just like a real plane, these jacks
allow the motion platform to move the
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in what's known as six degrees of
freedom.
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With
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its
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dynamic range of movements... and its
pinpoint accuracy, these motion
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have opened up a world of possibility
across a diverse range of applications.
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The engineering team at FAST is raising
this innovative motion platform
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technology to astronomical height.
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to search the sky with unbelievable
precision.
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Engineers created this.
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A lightweight cabin that can be moved
anywhere across the surface of the dish.
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real innovation.
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In here, we've got receivers sucking all
that data and sending it back to the
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control room.
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But in order to keep those in exactly
the right spot, we've got two different
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mechanisms at play.
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First, we've got those six towers out
there, which tug the cabin to
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approximately the right position using
the servo mechanisms and those six huge
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steel cables.
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Computers control each cable and
position the cabin as high as 450 feet
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anywhere along a 675 -foot trajectory.
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And like Capel's flight simulator, the
cabin pivots by using a motion platform.
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For that final bit of precision, we've
got those six hydraulic pistons
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controlling this platform, which allows
the position to be located to within one
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centimeter in this 500 -meter dish.
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But truly precise astronomy also depends
on the location itself.
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Human beings make a lot of electronic
noise, such as cell phone, microwave.
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All the electronic devices make magnetic
waves.
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So all these devices generate
interference to our telescope.
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To avoid any such radio interference,
engineers scope out a quiet, remote
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of southwest China in the Guizhou
province, 105 miles from its capital,
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But even out here, gathering highly
sensitive astronomical observations,
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have been impossible without one major
breakthrough from the past.
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At Green Bank Observatory in West
Virginia is an iconic device that
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one engineer's accidental discovery
unveiled a hidden universe.
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For most of the history of astronomy,
everything that we learned about the
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distant cosmos came from studying
optical light, the kind of light that we
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with our eyes.
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But in the 1930s, the dedication of one
man changed all of that.
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Bell Telephone Laboratories engineer
Carl Jansky was trying to eliminate
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interference in shortwave radio
communications across the Atlantic.
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To trace this interference, Jansky built
a large antenna.
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The antenna was mounted on a platform
sitting on tires that allowed it to
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rotate, taking a full 360 -degree scan
of the sky once every 20 minutes.
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His initial findings revealed a faint
but persistent hiss that would rise and
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fall throughout the course of the day.
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The signal was strongest in the
direction of the center of our galaxy.
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Jansky concluded that what he was
actually picking up... It was radiation
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the Milky Way galaxy itself.
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Jansky's extraordinary breakthrough
revealed a new corridor to the cosmos.
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Radio telescopes soon yielded
groundbreaking discoveries.
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And in 1964, astronomers used them to
actually record the faint echoes
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from the distant origin of the universe,
the Big Bang.
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Jansky's work offered definitive proof
that radio waves could be detected
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from the cosmos.
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Engineers at FAST are taking this
revolutionary radio technology even
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and are attempting to detect radio waves
emitted by advanced extraterrestrial
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life.
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But how do you assemble all the signals
from space?
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and transform them into usable data?
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I'm going to take that phenomenal amount
of data and turn it into a picture.
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To do this, the team must make the
impossible possible.
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In China, the fastest... Telescope is
the largest and most powerful single
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radio telescope on the planet.
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And this is where the action happens.
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This horn is part of a beam receiver.
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It slurps up those radio waves and
detects how strong they are.
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But this poses a huge challenge for the
engineers and scientists here at FAST.
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You've got to take that phenomenal
amount of data and turn it into a
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So how do astronomers and engineers
transform radio waves into images?
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Through the dramatic advances in
computer processing, the FAST team can
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transform faint radio wave signals into
otherworldly images.
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The modern radio telescope always tries
to visualize the radio signals you
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detect from the telescope.
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With a computer, you can display these
signals with different light curves.
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Astronomers use computer software to
label each individual wave with a color
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code. The buildup of color forms a
recognizable visual pattern.
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But to create such radio images,
astronomers must process a lot of data.
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We expect a fast can generate 40
terabytes per night, so we need a
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huge amount of storage system.
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00:20:08,190 --> 00:20:14,930
So here we have a lovely 1 .6 petabyte
storage, and also we have a high
233
00:20:14,930 --> 00:20:17,970
-performance computing system to process
the data.
234
00:20:20,240 --> 00:20:26,340
This is very exciting for each other,
also I think for the human being,
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00:20:26,340 --> 00:20:33,080
they all know some new knowledge about
the unknown, about the universe.
236
00:20:38,060 --> 00:20:44,420
Officially completed in September 2016,
FAST is now searching the skies further
237
00:20:44,420 --> 00:20:46,260
and deeper than ever before.
238
00:20:47,110 --> 00:20:51,750
Also scraping the Chinese sky... Look at
this superpower.
239
00:20:52,330 --> 00:20:57,670
...is China's tallest building and the
most technologically advanced skyscraper
240
00:20:57,670 --> 00:20:58,670
on Earth.
241
00:20:58,970 --> 00:21:00,990
I still feel like it's a dream.
242
00:21:01,310 --> 00:21:02,310
Still unbelievable.
243
00:21:09,530 --> 00:21:15,130
Shanghai is a megacity with 24 million
inhabitants and rising.
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00:21:15,420 --> 00:21:17,840
The only place left to build is up.
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00:21:20,480 --> 00:21:26,360
Over 2 ,000 feet high, the Shanghai
Tower is the tallest building in China
246
00:21:26,360 --> 00:21:29,500
the tallest skyscraper ever built in a
seismic zone.
247
00:21:29,700 --> 00:21:34,880
Building a super high -rise building in
Shanghai is quite unique because you
248
00:21:34,880 --> 00:21:38,720
have to deal with the wind low and also
the earthquake low.
249
00:21:39,980 --> 00:21:43,800
It's the most technologically advanced
skyscraper on the planet.
250
00:21:44,360 --> 00:21:51,360
With 128 floors and nine indoor gardens,
where 16 ,000 people work,
251
00:21:51,620 --> 00:21:52,680
sleep, and play.
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00:21:59,720 --> 00:22:04,920
Structural engineer Dennis Poon has to
take on many challenges, but must first
253
00:22:04,920 --> 00:22:06,800
start at the building's foundations.
254
00:22:07,360 --> 00:22:11,600
That's because the land under this
massive metropolis is sinking.
255
00:22:12,090 --> 00:22:16,650
Its shallow water table is collapsing
under the tremendous weight of the
256
00:22:16,650 --> 00:22:17,650
modern buildings.
257
00:22:17,830 --> 00:22:23,630
With its weight of 850 ,000 tons, how do
you support it? In the soft soil
258
00:22:23,630 --> 00:22:26,010
condition, which is locally in Shanghai.
259
00:22:26,730 --> 00:22:32,030
The engineers only have one shot, with a
skyscraper over 2 ,000 feet tall.
260
00:22:32,270 --> 00:22:37,070
For a supertower, of course, the whole
design challenge is to do the foundation
261
00:22:37,070 --> 00:22:40,610
right, so you don't have future
problems, because you can't fix it
262
00:22:41,050 --> 00:22:45,670
To bolster these foundations, engineers
must look to the great innovators of the
263
00:22:45,670 --> 00:22:46,670
past.
264
00:22:55,210 --> 00:22:58,970
Chicago is home to some of the world's
most iconic skyscrapers.
265
00:23:02,270 --> 00:23:07,190
But just over a century ago, building
anything taller than just a few stories
266
00:23:07,190 --> 00:23:09,110
was thought to be impossible.
267
00:23:12,620 --> 00:23:15,180
We've got soil here that is incredibly
squishy.
268
00:23:15,500 --> 00:23:18,860
This is a really difficult thing to
build a skyscraper on, of course,
269
00:23:18,860 --> 00:23:21,280
when you load the building, the
building's going to sink.
270
00:23:22,800 --> 00:23:28,300
As Chicago began to boom, the demand to
grow higher and maximize space posed a
271
00:23:28,300 --> 00:23:29,560
problem for city planners.
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00:23:30,200 --> 00:23:36,620
In 1889, the 236 -foot -tall auditorium
building at Roosevelt University was the
273
00:23:36,620 --> 00:23:42,000
tallest in the city. To overcome its
weak foundation, Engineer Dankmar Adler
274
00:23:42,000 --> 00:23:43,180
something extraordinary.
275
00:23:43,500 --> 00:23:47,640
We're headed down to see Adler's
specially designed foundations to deal
276
00:23:47,640 --> 00:23:48,780
soil here in Chicago.
277
00:23:49,520 --> 00:23:55,080
Adler's idea was to use wood and steel
crossbeams encased in concrete to create
278
00:23:55,080 --> 00:23:59,800
a reinforced concrete raft for the 110
,000 -ton building to sit on.
279
00:24:00,540 --> 00:24:05,300
The method that we're standing on here,
it's sort of the equivalent of...
280
00:24:05,530 --> 00:24:07,050
kind of penny that I'm going to
illustrate.
281
00:24:07,270 --> 00:24:13,810
So this pad or this raft is put down,
and then the building, the column on top
282
00:24:13,810 --> 00:24:18,310
of that is put on top of that. And you
can see that I can push it down a little
283
00:24:18,310 --> 00:24:22,050
bit into the clay, but not really that
far.
284
00:24:22,290 --> 00:24:24,610
This is distributing the load.
285
00:24:26,230 --> 00:24:31,670
Adler's revolutionary solution showed
how soft, substandard soil could support
286
00:24:31,670 --> 00:24:32,670
heavy buildings.
287
00:24:37,700 --> 00:24:43,320
To make the impossible possible,
engineers in China are taking Adler's
288
00:24:43,320 --> 00:24:48,040
raft design and supersizing it. If the
building does not settle uniformly, it
289
00:24:48,040 --> 00:24:48,839
will tilt.
290
00:24:48,840 --> 00:24:53,260
Because the building is so tall, a
slight tilting will cause a big
291
00:24:53,260 --> 00:24:54,260
the top.
292
00:24:55,420 --> 00:25:01,000
In 2008, the two -year operation to
build the Shanghai Towers Foundation
293
00:25:01,800 --> 00:25:06,660
First, workers sink hundreds of deep
supporting piles into the soil.
294
00:25:07,300 --> 00:25:14,200
For 60 hours, and with 450 concrete
trucks, 2 ,000 workers pour continuously
295
00:25:14,200 --> 00:25:15,620
create the concrete raft.
296
00:25:15,820 --> 00:25:19,720
You can see the sheer scale of this
tower, and you can imagine how big the
297
00:25:19,720 --> 00:25:23,940
foundation we need to support this tower
in a soft soil condition.
298
00:25:24,880 --> 00:25:26,260
And we get it done right.
299
00:25:26,460 --> 00:25:28,680
Look, I even cannot believe it.
300
00:25:31,660 --> 00:25:35,280
But the foundation of the Shanghai Tower
is just the beginning.
301
00:25:35,820 --> 00:25:39,960
For a super tall building, you have
enormous forces to support.
302
00:25:40,180 --> 00:25:44,560
We're not building a house, we're
building a 128 -story building.
303
00:25:44,860 --> 00:25:50,440
To design China's tallest skyscraper
with the strength to support over 800
304
00:25:50,440 --> 00:25:55,080
tons, engineers look to breakthroughs of
the pact to make the impossible
305
00:25:55,080 --> 00:25:56,080
possible.
306
00:26:02,120 --> 00:26:06,120
The Shanghai Tower, China's tallest
skyscraper.
307
00:26:06,360 --> 00:26:12,760
To design an epic building weighing over
800 ,000 tons, engineers must look to
308
00:26:12,760 --> 00:26:13,760
the past.
309
00:26:18,820 --> 00:26:24,320
They find inspiration, strangely enough,
in this crumbling mill in England.
310
00:26:26,120 --> 00:26:31,580
This incredible but rather sad and
dilapidated building in Shrewsbury is
311
00:26:31,580 --> 00:26:36,840
arguably the world's first skyscraper,
the first time that iron was used in a
312
00:26:36,840 --> 00:26:38,360
multi -story frame construction.
313
00:26:39,560 --> 00:26:45,620
Built in 1796, Ditherington Flax Mill
was the brainchild of engineer Charles
314
00:26:45,620 --> 00:26:46,620
Beige.
315
00:26:47,040 --> 00:26:51,360
Instead of relying on the wall, the
weight of the building is held together
316
00:26:51,360 --> 00:26:54,820
its iron frames, making the sky the
limit for the first time.
317
00:26:58,700 --> 00:27:03,160
This main building had five floors,
including this attic, which was
318
00:27:03,160 --> 00:27:09,380
unheard of. It had a working area of
over 2 ,800 square meters or 31 ,000
319
00:27:09,380 --> 00:27:14,340
feet. And these narrow, relatively
lightweight metal beams would be able to
320
00:27:14,340 --> 00:27:18,380
support much more weight than the solid
brick walls of previous buildings.
321
00:27:20,240 --> 00:27:24,320
What Beige achieved in this building was
truly remarkable.
322
00:27:33,740 --> 00:27:39,220
In China, the engineers are taking
Beige's revolutionary multi -story frame
323
00:27:39,220 --> 00:27:42,280
higher. Not with iron, but with steel.
324
00:27:43,720 --> 00:27:47,880
Because the external walls don't need to
be load -bearing, they don't even need
325
00:27:47,880 --> 00:27:48,819
to be straight.
326
00:27:48,820 --> 00:27:50,780
And they can be made with glass.
327
00:27:51,180 --> 00:27:52,760
The building looks different shape.
328
00:27:53,140 --> 00:27:54,460
The movement looks different.
329
00:27:54,760 --> 00:27:57,440
You feel like it's alive, something
alive organism.
330
00:27:58,080 --> 00:28:01,780
You know, because I don't feel like it's
a dead, just a cold object.
331
00:28:05,260 --> 00:28:10,280
With the internal steel frames holding
it, the glass forms a giant curtain.
332
00:28:10,980 --> 00:28:15,900
This distinctive architectural feature
gives the building its sense of breadth.
333
00:28:16,540 --> 00:28:20,220
Here we are. We are standing on the 8th
floor of the building.
334
00:28:20,460 --> 00:28:23,740
You don't want to block too much
sunlight to a massive structure. It
335
00:28:23,740 --> 00:28:24,740
every feeling.
336
00:28:27,700 --> 00:28:32,950
But elegant design aside... How do you
build a giant skyscraper that can safely
337
00:28:32,950 --> 00:28:35,430
transport 16 ,000 people daily?
338
00:28:36,110 --> 00:28:39,230
Who wants to come up to a 100 -story
building and work up there?
339
00:28:39,490 --> 00:28:44,730
This engineering feat would have been
impossible just a few centuries ago.
340
00:28:49,950 --> 00:28:55,870
In 1852, Elisha Otis pioneered a simple
mechanism that changed the elevator
341
00:28:55,870 --> 00:28:56,870
forever.
342
00:29:03,120 --> 00:29:08,020
So we're here in Bristol, Connecticut at
the Otis Elevator Company test
343
00:29:08,020 --> 00:29:11,700
facility. So I think it's important to
remember that Otis didn't invent the
344
00:29:11,700 --> 00:29:17,900
elevator. But what Otis did do was to
recognize that people were afraid of
345
00:29:17,900 --> 00:29:24,120
into an elevator. So at the 1853 -1854
World's Fair, he built this device to
346
00:29:24,120 --> 00:29:28,180
provide a break, a safety in case the
rope broke.
347
00:29:31,120 --> 00:29:36,720
At the World Fair, he stepped onto the
platform, rose above the crowd, and gave
348
00:29:36,720 --> 00:29:39,600
the signal for the rope of his elevator
to be cut.
349
00:29:40,160 --> 00:29:43,240
So let's see if Mr. Otis' invention
still works.
350
00:29:43,540 --> 00:29:44,700
Ready whenever you are, Rich.
351
00:29:50,620 --> 00:29:52,900
Otis' system features a wagon spring.
352
00:29:53,200 --> 00:29:57,220
It's held up by a rope, keeping the
spring in a state of constant tension.
353
00:29:57,660 --> 00:30:00,700
When the rope is cut, the tension in the
spring releases.
354
00:30:01,040 --> 00:30:05,200
causing pins fixed to the side of the
spring to lock into a ratchet located in
355
00:30:05,200 --> 00:30:06,200
the wood frame.
356
00:30:07,260 --> 00:30:10,780
This brings the falling elevator to a
complete stop.
357
00:30:11,620 --> 00:30:16,180
And all these years later, every single
elevator today around the world has a
358
00:30:16,180 --> 00:30:20,880
similar safety device that is allowing
passengers to feel safe in tall
359
00:30:20,880 --> 00:30:23,240
buildings. And I didn't flunge to my
death.
360
00:30:31,170 --> 00:30:36,110
Otis's first passenger elevator traveled
8 inches a second. At that speed, it
361
00:30:36,110 --> 00:30:39,330
would take nearly an hour to reach the
top of the Shanghai Tower.
362
00:30:39,670 --> 00:30:44,050
For this tower, we are using the world
fastest elevator traveling at 18 meters
363
00:30:44,050 --> 00:30:48,610
per second, which is faster than the
speed of a car traveling at normal
364
00:30:48,610 --> 00:30:49,610
speed.
365
00:30:51,710 --> 00:30:57,680
The Shanghai Tower boasts 106 elevators.
including one that travels a world
366
00:30:57,680 --> 00:31:00,920
record -breaking 1 ,898 feet.
367
00:31:07,100 --> 00:31:14,100
But at 128 stories, the Shanghai Tower
must brace against powerful
368
00:31:14,100 --> 00:31:19,200
winds. Even worse, Shanghai is in a
typhoon zone.
369
00:31:25,360 --> 00:31:27,500
which is almost 4 kPa.
370
00:31:27,740 --> 00:31:29,180
So it's a huge wind pressure.
371
00:31:29,480 --> 00:31:32,440
How do we resist this wind pressure?
372
00:31:34,300 --> 00:31:40,220
For China's tallest skyscraper to
overcome this force of nature, engineers
373
00:31:40,220 --> 00:31:41,520
brace it for the storm.
374
00:31:41,720 --> 00:31:45,820
We start to get this low pressure, low
pressure, low pressure, low pressure,
375
00:31:45,820 --> 00:31:48,580
that causes this oscillation back and
forth.
376
00:31:49,160 --> 00:31:51,780
And make the impossible possible.
377
00:32:03,950 --> 00:32:08,910
At over 2 ,000 feet high, the Shanghai
Tower is the tallest in China.
378
00:32:09,130 --> 00:32:14,230
But to brace this skyscraper for typhoon
-level winds, engineers must rely on a
379
00:32:14,230 --> 00:32:16,390
far -reaching innovation from the past.
380
00:32:22,970 --> 00:32:29,530
In 1959, engineer Jack Cermak pioneered
the first wind tunnel designed for
381
00:32:29,530 --> 00:32:30,530
buildings.
382
00:32:31,630 --> 00:32:37,730
At wind engineering firm RWDI, engineers
test multiple architectural shapes
383
00:32:37,730 --> 00:32:39,710
against a variety of wind currents.
384
00:32:40,170 --> 00:32:45,130
A scale model of New York's former World
Trade Center is being placed into a
385
00:32:45,130 --> 00:32:49,730
model of the London skyline to see what
effect wind can have on tall buildings.
386
00:32:50,060 --> 00:32:54,060
So the wind is coming in here, it's
hitting the side, and then as it comes
387
00:32:54,060 --> 00:32:56,840
around the corner, it produces a low
pressure region here.
388
00:32:57,060 --> 00:33:00,680
And that causes the movement, the
building, to move this way. But then
389
00:33:00,680 --> 00:33:04,560
means that the wind coming around this
end starts to cause a little bit of
390
00:33:04,560 --> 00:33:08,460
movement this side and low pressure. So
we start to get this low pressure, low
391
00:33:08,460 --> 00:33:12,920
pressure, low pressure, low pressure,
and that causes this oscillation back
392
00:33:12,920 --> 00:33:13,920
forth.
393
00:33:16,080 --> 00:33:20,040
For architect, the challenge is to come
up with a shape that reduces those
394
00:33:20,040 --> 00:33:21,040
vortices.
395
00:33:23,600 --> 00:33:25,160
Okay, let's try this one.
396
00:33:27,180 --> 00:33:30,640
This time the building is tapered like
an elongated pyramid.
397
00:33:34,200 --> 00:33:37,940
We're running at three times the wind
speed of that very first model that we
398
00:33:37,940 --> 00:33:41,780
saw. And the building's just not moving
anything like this violently.
399
00:33:43,120 --> 00:33:47,140
Because of the tapered shape of the
building, the wind creates vortices of
400
00:33:47,140 --> 00:33:48,900
different sizes at different heights.
401
00:33:50,160 --> 00:33:53,580
Different parts of the building are
trying to shake at different rates,
402
00:33:53,900 --> 00:33:55,120
canceling each other out.
403
00:33:58,540 --> 00:34:04,220
Jack Cermak's wind tunnel allowed city
skylines around the world to grow taller
404
00:34:04,220 --> 00:34:05,520
and more safely.
405
00:34:14,800 --> 00:34:19,679
Because of the wind, the Shanghai Tower
is tapered, but it also has a
406
00:34:19,679 --> 00:34:25,460
distinctive twist, one that reduces wind
loads on the building by 24%. The
407
00:34:25,460 --> 00:34:30,139
twisting of the building is a great
example for engineers that can combine
408
00:34:30,139 --> 00:34:33,440
creative architectural design with good
engineering.
409
00:34:33,980 --> 00:34:39,420
To accentuate this, architects implement
a notched V across the entire length of
410
00:34:39,420 --> 00:34:40,198
the building.
411
00:34:40,199 --> 00:34:43,040
Once you have this brick, the V, you can
actually read.
412
00:34:53,770 --> 00:34:59,630
But the tapering, the twist, and the
notch also brace the building against
413
00:34:59,630 --> 00:35:00,630
wind.
414
00:35:01,930 --> 00:35:07,470
of the building helps the aerodynamic
the twisting helps and the notch helps
415
00:35:07,470 --> 00:35:11,330
at the same time the tapering also
lowers the center of gravity of the
416
00:35:11,330 --> 00:35:16,210
that gives us more stability the lower
the center of gravity the more stable
417
00:35:16,210 --> 00:35:23,190
building is but the shanghai tower faces
a natural force
418
00:35:23,190 --> 00:35:28,870
even more destructive than high winds
earthquakes
419
00:35:33,290 --> 00:35:37,890
Of course, we're not only designing this
building for typhoon, we know up to 120
420
00:35:37,890 --> 00:35:41,330
miles per hour, we know. We also have to
design it for significant and severe
421
00:35:41,330 --> 00:35:42,330
earthquakes.
422
00:35:42,750 --> 00:35:47,590
So, how do you build China's tallest
building to withstand an earthquake in a
423
00:35:47,590 --> 00:35:49,170
level 3 seismic zone?
424
00:35:49,490 --> 00:35:53,850
Engineers look to neighboring Japan to
make the impossible possible.
425
00:36:04,029 --> 00:36:07,330
China's tallest skyscraper is the
Shanghai Tower.
426
00:36:07,690 --> 00:36:13,350
Built in a level 3 seismic zone,
engineers must design a building 2 ,000
427
00:36:13,350 --> 00:36:17,910
high that's also able to withstand
Mother Nature's most brutal force,
428
00:36:18,110 --> 00:36:19,110
earthquakes.
429
00:36:22,550 --> 00:36:27,850
To overcome this daunting task,
engineers look to neighboring Japan for
430
00:36:27,850 --> 00:36:28,850
inspiration.
431
00:36:37,870 --> 00:36:42,490
As the most seismically active country
on the planet, Japan's earthquakes have
432
00:36:42,490 --> 00:36:47,110
collapsed countless buildings, but
traditional pagodas somehow remain
433
00:36:47,970 --> 00:36:51,670
The secret to the pagoda's survival is
hidden inside.
434
00:37:13,520 --> 00:37:16,520
The typical pagoda consists of five
floors.
435
00:37:16,820 --> 00:37:20,260
Its floors have the ability to move
independently of each other.
436
00:37:20,640 --> 00:37:24,740
When an earthquake strikes, its snake
-like pattern keeps the center of
437
00:37:24,740 --> 00:37:26,980
more upright than a rigid building wood.
438
00:37:28,340 --> 00:37:32,380
And the wooden joints that support each
floor are made up of several separate
439
00:37:32,380 --> 00:37:37,920
components. so each part can slide and
move. The friction the parts create acts
440
00:37:37,920 --> 00:37:40,500
like a shock absorber and softens any
movement.
441
00:37:49,820 --> 00:37:54,300
Today's engineers are taking the
Pagoda's innovative earthquake -proof
442
00:37:54,300 --> 00:37:56,860
and giving it a 21st century spin.
443
00:37:59,020 --> 00:38:03,900
The Shanghai Tower's structure is
divided into nine vertical zones around
444
00:38:03,900 --> 00:38:06,320
central composite steel and concrete
core.
445
00:38:07,600 --> 00:38:12,540
To further strengthen the tower, huge
perimeter columns and outriggers have
446
00:38:12,540 --> 00:38:13,940
attached to the central core.
447
00:38:14,560 --> 00:38:19,420
The core is just like the main chunk of
your body, and the two whole columns,
448
00:38:19,540 --> 00:38:24,080
the exterior column outside is like the
steeple. And this steel truss member is
449
00:38:24,080 --> 00:38:25,560
connecting your body.
450
00:38:25,960 --> 00:38:30,940
and the column giving you a much better
stability for the building to resist
451
00:38:30,940 --> 00:38:35,720
earthquakes. The earthquake -proofing
measures extend from the base of the
452
00:38:35,720 --> 00:38:36,720
to its tip.
453
00:38:38,360 --> 00:38:45,080
Here we are, coming up to the 125th
floor of the tower, which is one of the
454
00:38:45,080 --> 00:38:46,640
important rooms in the building.
455
00:38:47,140 --> 00:38:52,640
You can see we have 1 ,200 tons of steel
blocks.
456
00:38:52,990 --> 00:38:55,490
being hung four stories above us.
457
00:38:55,990 --> 00:39:01,410
So why are engineers taking up valuable
floor space with a steel block that
458
00:39:01,410 --> 00:39:04,550
weighs the equivalent of 600 four -door
sedans?
459
00:39:05,010 --> 00:39:08,390
Engineers look to a groundbreaking
building in Boston.
460
00:39:13,570 --> 00:39:17,670
The John Hancock Tower was completed in
1976.
461
00:39:18,170 --> 00:39:23,620
But immediately upon completion, The
building perilously swayed with the
462
00:39:25,500 --> 00:39:29,200
Engineer William LeMessure came up with
an ingenious solution.
463
00:39:30,760 --> 00:39:37,240
What I've got here is a very simple
model of a skyscraper. It's a beam
464
00:39:37,240 --> 00:39:39,540
structure going up several stories.
465
00:39:42,200 --> 00:39:45,600
Turning a handle at the base of the
structure mimics an earthquake.
466
00:39:46,100 --> 00:39:48,340
You do have this problem with sway.
467
00:39:51,340 --> 00:39:56,700
Le Mejure tried to counteract the
building's sway with two steel boxes
468
00:39:56,700 --> 00:40:01,000
the 58th floor, each filled with several
hundred tons of lead.
469
00:40:01,540 --> 00:40:07,040
You have to imagine this is an 800 -ton
weight that I'm lifting up onto my
470
00:40:07,040 --> 00:40:10,100
skyscraper now, and I'm just going to
tie it to the top of my structure.
471
00:40:11,080 --> 00:40:16,220
The tuned mass damper, or TMD as it
became known, had a dramatic effect.
472
00:40:17,460 --> 00:40:18,460
It's amazing.
473
00:40:18,780 --> 00:40:20,280
The structure is hardly moving.
474
00:40:20,600 --> 00:40:21,680
I mean, it's quite phenomenal.
475
00:40:22,860 --> 00:40:24,700
The principle is simple.
476
00:40:24,940 --> 00:40:29,660
As the building starts to sway, the
damper travels in the opposite
477
00:40:29,880 --> 00:40:31,820
balancing the overall building.
478
00:40:32,160 --> 00:40:35,900
It's amazing how much of an impact it
has.
479
00:40:36,340 --> 00:40:40,600
Without tuned mass dampers today, we
just wouldn't have any of the kind of
480
00:40:40,600 --> 00:40:45,860
structures that we have. The Shanghai
Tower's engineers have taken LeMessure's
481
00:40:45,860 --> 00:40:47,940
damping system to a whole new level.
482
00:40:52,440 --> 00:40:57,240
Without these two mass damper, we have
to use a lot more structural steel and
483
00:40:57,240 --> 00:40:59,240
material to stiffen up the building.
484
00:41:00,680 --> 00:41:06,420
Despite taking up five floors and
weighing over 1 ,000 tons, the Shanghai
485
00:41:06,420 --> 00:41:11,520
Tower's tuned mass damper actually makes
the building cheaper and lighter to
486
00:41:11,520 --> 00:41:12,520
construct.
487
00:41:23,500 --> 00:41:28,800
After 15 years of planning and seven
years of construction, engineers
488
00:41:28,800 --> 00:41:34,840
China's tallest skyscraper in 2016 with
the 2 ,000 -foot -high Shanghai Tower.
489
00:41:36,020 --> 00:41:41,420
By drawing on innovations of the past
and making groundbreaking discoveries of
490
00:41:41,420 --> 00:41:47,060
their own, the engineers of the FAST
telescope and the Shanghai Tower have
491
00:41:47,060 --> 00:41:51,860
created China's biggest structures and
some of the largest on the planet.
492
00:41:54,250 --> 00:41:57,170
They've made the impossible possible.
493
00:41:57,220 --> 00:42:01,770
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