These are drops of water.
In 1894, photographs like these were new wonders, revealing the beauty and the underlying
physics of a simple splash.
Photography had succeeded in making a physical observation that was impossible for the naked
eye.
In the next hour, we'll explore many of the wonders of photography, and especially of
cinematography, the science of motion pictures.
For us, time is as continuous as the rotation of the earth, but photographers have learned
to cheat time, so that days shrink to seconds, and seconds expand to hours.
We have extended the limits of human vision.
By telescoping time, changes in nature too slow for us to perceive directly can be seen
and studied, and by magnifying time, movements too rapid for the eye to follow can be slowed
down and analyzed.
When the first photographic experiments were attempted, however, all that the early pioneers
could do was to uncap their lenses and wait.
In fact, when Nyssa Fornieps, a French landowner and amateur inventor, took what is generally
acknowledged to be the earliest known photograph, a view of his own backyard in central France,
it took a full eight hours of strong sunlight to imprint the scene on a bitumen-coated plate
in his camera.
The device Nyssa Fornieps used was similar to this.
It was called a camera obscura, and because it could project an image onto a screen, which
could then be traced onto paper, it was often used as an artist's aid.
It was after using such a device to assist him in his sketching that an Englishman called
William Fox Talbot wrote the following words in his diary.
I was amusing myself on the loveless shores of the lake taking sketches, or rather I should
say attempting to take them, when the idea occurred to me how charming it would be if
it were possible to cause these images to imprint themselves durably and remain fixed
upon the paper.
The year was 1833, and the idea fired Fox Talbot to begin the experiments which would
establish him as one of the pioneers of modern photography.
By the summer of the following year, here in the long room at his home in Wiltshire,
he achieved his ambition.
A tiny camera obscura with a sheet of sensitized writing paper placed in the back was left
on the mantelpiece for an hour or two pointing toward the leaded window opposite.
This tiny photograph was the result.
Using the system that Talbot eventually developed, Brian Coe, curator of the Kodak Museum in
London, describes the limitations of the early photographic techniques.
We've just started a process that's going to take about two hours.
We're making a photograph by the earliest practical method of photography of Harrow
School where Fox Talbot gained his education at the beginning of the last century.
It's going to take two hours because the picture is going to print out on the paper by the
direct action of light.
In that time, there will be hordes of Harrowians moving backwards and forwards up those steps.
Not one of them will appear because he will never stand still long enough to record on
the very slow paper.
The problem was that it was fine if he wanted to photograph a building or a tree which wasn't
going to get up and move, but anything involving action, whether it was people or moving leaves
on trees or whether it was moving water or whatever, would just, it would simply not
appear or would appear as a featureless blur.
And for about the first 20 or 30 years of photography, this was the problem.
Any kind of photograph that you took, except in very special circumstances, would not show
action, it would not show streets full of people, it would not show sharp and clear
pictures of animals, unless you took a great deal of trouble to pose everybody and make
them stand still.
So there were little tricks of the trade.
If you were photographing ships on a river, for example, you waited till low tide when
the ships were grounded so they couldn't rock backwards and forwards during a long exposure.
But the recording of action in anything other than a simulated form was impossible.
Tolbert, for example, took pictures of people at work, carpenters, bricklayers, but it was
done by making them adopt a natural-looking pose and to hold it for minutes on end.
But there were ways in which photography could extend human vision.
Sir John Herschel, the great astronomer, pointed out that photography for the very first time
showed something the human eye could not see in a series of photographs taken by Warren
Delarue, the great astronomer, who took pictures of the moon over quite long intervals, a matter
of years, so that the point of view of the moon was substantially different.
If these two pictures were put together and viewed in a stereoscope, a gadget which enabled
one eye to see one picture, the other eye to see the other, they fused to make a sphere.
The moon was seen as a spherical object, something which was deduced but could never be seen
with the naked eye, at least not until the Apollo missions demonstrated it really was
true.
So photography helped early scientists to push back the frontiers of knowledge with
not only with recording but also extending vision.
Unfortunately for Talbot, however, public attention was soon focused once again across
the channel to France.
Then at the end of the decade, this man, Louis Daguerre, announced a new invention to the
world.
It was a form of photography called daguerreotyping, and for a little over $480, a kit like this,
signed personally by Monsieur Daguerre, would enable you to obtain a detailed photograph
after just a few minutes' exposure.
Daguerre received mixed responses.
He was called everything from a prodigy to blasphemous.
But one report drew attention to a significant limitation of the new technique.
So even in bright sunlight, movement still eluded the new art.
Photographers lived within this limitation for 15 years, until one day, back in England,
Fox Talbot realized that the sun was not the only source of bright light.
And this is what he did.
Instead of using sunlight to work for hours and hours, he used an artificial light source.
He took a machine rather like this, a Wimshurst machine, which generates static electricity
when the handle is turned, and used it to charge up a room full of primitive capacitors,
laden jars, which stored the electricity at a very high voltage. When all was ready,
he placed in front of his camera, on a rotating disc, a page of a newspaper, an agent has
it that it was a copy of the Times.
The disc was rotated at high speed, so that it just became a blur.
He uncapped the lens in a subdued light, fired the laden jars through a spark gap, producing
a brilliant flash of light, and then covered the lens again.
The result, when he processed his plate, was a faint but just visible image of the page
of the paper, sharp, every detail, every letter readable, every word visible.
He'd frozen the rapid movement of the disc by an extremely brief exposure of about one
hundred thousandths of a second, and had anticipated the high-speed electronic flashes of today
in 1851.
Fox Talbot had taken the first high-speed photograph, but the idea was ahead of its
time. It was another thirty years before Ernst Mach, who gave his name to the speed of sound,
took this, the first ballistic photograph of a bullet in flight, using spark technology.
By the end of the century, A.M. Worthington, a British professor of physics, was using
sparks for his splash studies, pulling exposure times down to under one hundred thousandth of a second.
By the early 1930s, this splash had been achieved with a flash of light lasting less than one
millionth of a second.
It heralded the arrival of a revolutionary new device, the stroboscope.
Not only could the stroboscope provide a single brief time-freezing burst of light, it could
also be flashed rapidly to produce other improbable effects.
In certain circumstances, it can produce a kind of living slow motion, visible even to
the unaided eye. This is not trick photography. It's the effect of stroboscopic lighting.
Dr. Harold Edgerton, inventor of the stroboscope and a pioneer of modern high-speed photography,
explained.
This experiment shows a single-pillar hydraulic happening machine, which consists of a small
pump which sends water in a stream at sixty times per second.
With ordinary light, the human eye is incapable of seeing these drops, so it appears like
a continuous stream.
If now I flash a strobe on it in synchronism at exactly sixty times per second, then the
drops will appear like they're standing still.
I should point out that the flashes of light from the stroboscope that I have up above
here are less than ten microseconds in duration. In other words, the flashes of light are less
than one hundred thousandth of a second.
The drops appear sharp and distinct, and because they're pushed by a pump, they are coherent.
Every drop is exactly like every other drop.
However, there is liquid in between. If I put the pencil in between the drops, there's
going to be a splash, because of course the drops actually fall from there to there in
one sixteenth of a second. Although it looks like there's no drop in between, if you put
your finger in there, you'll get it wet, because there's water coming through there all the
time.
This experiment shows two streams. The two streams are arranged so that the drops come
from exactly the right height, so that they collide.
When they hit, there's nowhere to go except out, so they make a beautiful, very thin disk
of liquid, and then eventually the liquid falls away into a pattern with drops on the
edge.
When finely tuned, a stroboscope can produce even more improbable effects.
This saw is actually rotating at 3,000 RPM, frozen by a stroboscope flashing in perfect
synchronization. And because of this ability to freeze any repeating or cyclic action,
strobe lighting can be used today to check anything from the timing of your car to the
printing accuracy of a labeling machine.
Beyond the visible spectrum, strobe X-rays can reveal the inner dynamics of the internal
combustion engine. And when combined with still photography, the rapidly flashing strobe
can illuminate different phases of a single movement to produce studies that show dissected
action in a single image.
The same thing capturing motion on a single photograph was being attempted nearly a hundred
years ago by the French physician Jules-Chen Méré at his laboratory on the outskirts
of Paris.
Half a century before the stroboscope would be invented, Méré achieved very similar results
using a rotating shutter in his camera. To apply photography to the study of motion,
Méré used various ingenious tricks. Here he has pinned white cord along the limbs of
a man dressed in black velvet.
The resulting photographs of the man's movement are living graphs displaying the fluency of
action on a single picture and revealing new and previously invisible anatomical relationships.
At about the same time in California, another milestone in the photographic analysis of
movement was reached. An English photographer, Edward Mybridge, had been called in to settle
a bet about whether or not, at some point in a racehorse's stride, all four hooves
left the ground at the same time.
To tackle the problem, Mybridge erected a shed beside the racetrack in Sacramento and
placed twenty-four cameras in a row along one side. The cameras were numbered and could
be triggered in sequence when the moving horse broke tripwires connected to each shutter.
The evidence of each high-speed exposure was unimpeachable. For an instant, the hooves
were in the air together, and Mybridge won immediate acclaim.
By 1880, Mybridge was giving lectures on the subject of animal locomotion. To illustrate
those talks, he transferred some of his still sequences onto a glass disc, which was then
placed into what he called a zoopraxis scope, a device similar to a popular parlor entertainment
machine. With the zoopraxis scope, he was able to reproduce the illusion of movement.
It was the first projected moving picture show, and the demonstration was a sensation
wherever it was shown.
In France, meanwhile, Marais had also been working with spinning glass discs, not to
reproduce movement, but to record it. This rare footage taken when Marais was an old
man shows the method he devised. Using a camera that looked more like a shotgun, he would
take aim at his subject and expose twelve separate images on the spinning plate. Each
picture was taken in a few hundredths of a second and captured the successive positions
of a bird in flight.
The glass plate was not without its problems, however, and for this famous sequence of a
falling cat, Marais used a moving strip of film to capture each new position. In seeking
to perfect an instrument for the scientific analysis of movement, Marais had hit upon
the principle of the modern motion picture camera. But he also discovered the secret
of a cat's agility. The trick involved extending the tail and rotating it rapidly in one direction
while the cat arches and twists its body in the other. The resulting turn is achieved
by causing two opposing actions to cancel each other out.
Marais' passion for seeing the unseen also led him to experiments in aerodynamics. These
have been called the first wind tunnel pictures, even though they were actually taken in a
sealed glass-fronted box with a velvet-covered interior. Marais introduced threads of smoke
under pressure and photographed them as they flowed and eddied past different obstacles
placed in their path.
After visiting France to compare notes with Marais, Mybridge returned to the United States
to continue preparing a volume of motion studies containing no less than 100,000 separate pictures.
The year was 1883. It was a huge success.
Recording everything from cheetahs to cart horses, rhinos to raccoons, he used as many
as 60 electrically synchronized cameras to freeze instance of time and then recombine
them to recreate movement. It was inevitable that these experiments in photographic alchemy
would soon lead to the birth of motion picture photography.
In 1889, Thomas Edison applied George Eastman's new roll film to a device he called the kinetoscope
and Fred Ott, a worker at the Edison factory, posed and sneezed for the first true movie
sequence. Although Edison's kinetoscope worked, it was the French Lumiere brothers who developed
the first practical motion picture equipment and their cinematograph was eminently practical.
It was portable, it operated at just 16 frames per second, and most importantly, it served
as both camera and projector.
The Lumiere shot their first film in 1895. Unlike Fred Ott's sneeze, the Lumiere film,
showing workers leaving their factory at lunchtime, was spontaneous and unstaged. It was the first
documentary film. Such was the appeal of Lumiere's pioneering films that their programs filled
the new cinemas from Lyon to Paris. The range of films on the program was extensive and
at times more than a touch bizarre, ranging from snowball fights to demolition work.
But although the Lumiere's considered themselves scientists rather than artists, they were
not entirely above what was later to be called slapstick comedy, and in 1896 they were the
first to record this classic visual joke.
As the 19th century drew to a close, one of Lumiere's pupils, a student of human anatomy,
devised and shot this, the first true slow motion, which magnified time almost six times.
And in 1898, a German botanist called Wilhelm Pfeffer took a picture every 15 minutes to
create the first time lapse photography sequence, compressing the 11 days growth of these beans
into just a few seconds, and thereby telescoping time 12,000 times. Meanwhile, Lumiere himself
continued to invent applications for the new action picture technology, such as combining
the time lapse camera and the microscope to film blood corpuscles in motion.
In 1911, cinema audiences were treated to this short time lapse sequence, in which for
But for all the elegant simplicity of the results, time lapse photography is a highly
specialized technique, and not without its surprises.
Nearly always, if it's biological material that you're filming, there's something unusual
happening to the plant or the animal or the flower that's filmed. There was a particular
shot which comes to mind of a type of everlasting flower, which I wanted to film opening. But
when I got the film back, I found that the petals, which are arranged in radial rings
around the center, didn't just open. They opened and then shut a bit and then opened
a bit more and shut a bit and finally it opened. And it took perhaps a dozen of these cycles
for the flower to finally open. The function of these petal movements, I have no idea of
and I don't think anyone else would. It's probably never been noticed before. So you
take a shot of a thing without really knowing what it's going to do, other than, you know,
the beginning stage and the end stage you're aiming at. But in between that, it's fairy
tale land. It's a surprise every minute.
One particular shot which has given us great pleasure at OSF is a sequence which I took
of the destruction of a dead mouse carcass by blowfly maggots. And I thought it would
be rewarding to record this on film, but when the film came back, the behavior of the maggots
was astonishing.
They acted as a coordinated workforce because they exude a digestive juice which helps to
rot and break down the carcass and then they reabsorb the materials which the juices produce.
Having seen the film, one now sees what they do. If they work as a bunch, they are swimming
in one another's juices and have a more rapid effect on the carcass. And so these maggots
moved around the carcass in a great group and they sort of ate one end and then as a
great group they rushed up to the other end and dissolved that and as the carcass became
more disseminated, only then did the maggots start to move off individually and seek what
they could.
We ought to do a shot one day of maggots dissolving an elephant carcass. Really quite spectacular.
Starting off with some unfortunate dead animal and finishing up with a pile of bleach bones.
For a change of pace, this time lapse film was a source of pleasure to millions in the
1950s when it was made. We invite you now to take a trip to the seaside and although
we're going by train, thanks to trick photography, we're able to rush you from London to Brighton
in four minutes. So let's find our train at Victoria.
To
the movie and TV audiences who saw this film, the prospect of traveling from London to Brighton
at an average speed of 760 miles an hour was no more than an intriguing curiosity. But
the railway companies took time lapse photography seriously. They used it as an aid for improving
carriage layout and seat design. Analyzing the film frame by frame, the designers counted
every fidget and leg crossing. Curiously, it showed men to be more restless than women
adopting no less than 50 different seating postures, whereas women used fewer than 40.
A little further from home, the Apollo astronauts were filmed using time lapse. Of course, because
time lapse needs less film, there was less weight to carry. As a comparative tool, two
sets of time lapse taken before and after road construction have been used to show improvements
in traffic flow. Here, the new road markings enabled an extra 1,000 vehicles an hour to
use the junction. The distortion in this image is caused by the fact that the camera is looking
up into a convex mirror and can be seen photographing itself in the center of this picture. Some
years ago, a photographic film manufacturer took this idea and turned it upside down so
that research scientists could measure brightness of the sky at different periods during the
day.
This time lapse sequence shows a year's movement in the river of ice that is the Grindelwald
glacier. And at the microscopic end of the scale, the ordered complexities of cell division
in a rabbit egg. Time lapse again reveals beauty while serving as a tool for the scientist.
These shellfish, called sand dollars, bed themselves into the sea bottom for the night.
But other sea creatures continue to be active. To the unaided eye, these limpets would normally
appear as unmoving as the rocks. This is a new view of undersea activity in which hours
have been telescoped into seconds. Movement has been speeded up 400 times. But cinematography
can slow time as well, expanding each second, magnifying each moment. The high-speed camera
then becomes a kind of time microscope.
There are lots of different sorts of high-speed cameras. There's the camera which is analogous
to the simple magnifying glass, one which will magnify time maybe 10 or 100 times. Then
there is the high-speed camera that will magnify time a thousand times. And then just as with
the microscope, we have to leave the optical instrument and go into the electron instrument.
So with the cameras, the high-speed cameras, we have to switch to electronic high-speed
cameras to magnify time perhaps a million times.
At the magnifying glass end of that high-speed spectrum, an estimated 7,000 cameras are now
in use around the world, recording events in slow motion. Although they offer only a
relatively modest degree of time magnification, slowing movement by 10 or 20 times, because
of the way they work, these cameras give exceptional picture quality. And picture quality means
information. These cameras owe their ancestry to the earliest days of cinematography. For
despite the extremely high speeds at which these mechanisms can operate, cameras like
this are effectively taking a sequence of high-quality still photographs. Single frames
of film are halted in front of the shutter and located securely on two or more retractable
spikes called register pins. While the film is stationary, a picture is taken. The register
pins are then retracted and the film is moved on to the next frame. Cameras that use this
principle are called intermittent action cameras. And in normal film and TV operations, these
cameras will take 24 single frames each second. There's also a high-speed version of the same
mechanism capable of operating at up to 500 frames a second. A slow motion photographic
record of an event, in this case taken from a position no human observer could endure,
can later be analyzed frame by frame to show scientists and engineers whether what they
expected to happen did happen. And if it didn't, these frames of film can show why. Here, one
of the main rocket engines has failed to ignite, and the resulting imbalanced thrust is flipping
the unmanned rocket onto its nose. And here, both the first and second stage boosters of
another unmanned rocket have fired together with spectacular results. These records answer
the question, what went wrong? Used as a diagnostic tool in industry, an unbalanced lathe when
filmed at extremely high speed can be seen cutting unevenly. And here, a nail machine
has been asked to produce more nails per minute than it was designed to handle. This man has
just dropped a small metal bolt into the intake of this jet turbine. Slow motion photography
reveals why this is not a wise thing to do with a running engine. In a more peaceful
vein, bird flight has been attracting cinematographers' attention ever since Dr. Marais began shooting
birds with a camera. Here, a controlled stall enables a pigeon to land on a dime. Well almost.
And here, a hungry chickadee deals with a couple of claim-jumping sparrows. Hummingbirds
represent one of the greatest challenges to wildlife cinematographers, beating their wings
as many as 70 times a second. Their metabolic rate is so high and their perception of time
so rapid that to them a moving human photographer appears as motionless as the starfish we saw
earlier. In a way, hummingbirds would need time-lapse photography to see us move. In
the grand tradition of Marais and Mybridge, earthbound animal locomotion continues to
be a source of fascination. Even in slow motion, the acceleration that this cheetah can achieve
is startling. As he races after the Thompson's gazelle at speeds in excess of 60 miles per
hour, the unique flexibility of the cheetah's back enables him to cover eight yards with
each stride. Watch how he uses his tail to keep his balance in the sharp turns. The gazelle
is running for his life. His only hope is to zigzag in order to dodge the heavier cat.
He is all too aware that in a straight race he would certainly be caught. This time the
gazelle is safe, at least until the cheetah can get his breath back. And while we're thinking
of the flexibility of an animal's spine, remember Marais' falling cat. Here's a dog that's about
to apply a similar principle. After being dunked in the river, he's starting to shake
himself dry. The shake starts at his nose and travels the length of his body to his
tail. And so that he doesn't throw himself off his feet at full shake, half of his body
is twisting one way and half the other. Peter Parks, a cameraman who specializes in slow
motion studies of animals, explains the technical background to the shot. To capture that sort
of action on high speed film is not too much of a problem. We used in that case a camera
which is capable of giving us up to 500 frames a second. And that camera is a register pin
or intermittent action camera. Now that's okay for the dog shaking. But as soon as you
want to start seeing what's happening to the drops of water that are flying off the dog,
particularly when they land on surrounding vegetation, people, insects, whatever, then
you need a frame rate which is considerably greater, something like 1500 frames a second.
And there we were using a camera which works on a totally different system. To try stopping
and starting film at these speeds would invite disaster. And so in this camera, the film
is always moving. To prevent blurring, a rotating glass prism is locked to the motion of the
film, keeping the image steady on each frame while it's being exposed. Such a camera can
take up to 10,000 separate pictures in each second. Here, a rotating prism camera has
taken 3,000 pictures per second of this crane fly. And slowing time 120 times, the two small
vestigial wings called the halteres can easily be seen swinging up and down. To the unaided
eye, they're only a blur. But now that their action can be seen clearly, it's thought that
they are used like counterweights, steadying the insect while it is in flight. It illustrated
in a very nice way, something which one had learned in a dry, dusty textbook and seen
in very poor form. And we saw it very clearly on the filming we were doing. And if there
seems no limit to nature's ability to achieve the impossible, equally there seems no limit
to photography's ingenuity in seeing it. The tip of this 40 millimeter cannon shell has
been coated with reflecting paint because photographers here at the Royal Armaments
Research Establishment plan to film it on its four millisecond journey along the barrel.
The problem is simple. How do you look down the barrel while the shell is coming up? It
is of course all done with mirrors. A high speed camera is lined up to look directly
down the barrel by means of one mirror. And then a second half silvered mirror is placed
across the camera's path so that an extremely strong light source can illuminate the face
of the painted shell. Enough film to last five minutes when projected at normal speed
goes through this camera in just over half a second, stretching time 400 times. The shell
will leave the muzzle of the gun at over three times the speed of sound. And on an open range
it would travel 1,000 meters within the next second. You might think that's the last you'd
see of it, but ballistics experts want to see what's going on while the shell is in
flight, even though this means filming a small supersonic object and following it as it travels
hundreds of meters in each second. To solve the problem, the high speed photographers
again use a rotating prism camera. And again, it's all done with mirrors. This time it's
one that can pivot very quickly. Called the fastest pan in the world, the whole event
happens so quickly that the gun has to be fired automatically by the camera control
equipment when the film speed and mirror alignment are just right. And this is the result. The
shell has just left the barrel and we've frozen the film for a moment so that you can pick
it out more easily. Actually, it's moving at 2,000 miles an hour as it spins and wobbles
its way down the range. Like so many modern applications of photography and science, ballistic
studies were conducted almost as soon as cinematography began. A ball bouncing on a jet of water was
another early high speed study. Slowed down 50 times, a paper pellet pierces a bubble
in 1905. And in 1909, 200 times slow motion. Today, ballistic motion picture technology
can even be used to produce single high quality still pictures of a bullet in flight by a
method known as ballistic synchro photography. The bullet will be fired past a battery of
flash bulbs and for the briefest instant will pass through the ballistic synchro camera's
field of vision. Inside the camera, traveling at exactly the right speed in the opposite
direction to the bullet, the film records not a blur but a crystal clear picture of
the subject as it passes the narrow imaging slit in the camera. As it cracks past the
lens at 2, 3 or even 4 times the speed of sound, the exact condition of the projectile
is frozen for later analysis. Incredibly, despite the fact that we've been looking
at progressively faster events, we are not yet completely beyond the range of human activity.
This man has a black belt in Taekwondo, a branch of the martial arts which specializes
in developing speed and strength. A test of that speed and strength and also a test of
resolve is the ability to break things and here, 7th Dan Black Belt Master Alexander
Reeve prepares to punch through a pile of wooden blocks. Two years ago, a physics professor
at the Massachusetts Institute of Technology who had taken up karate as a hobby began to
wonder how such a feat was possible. To see more clearly what was happening, he turned
to high speed photography for the answers. Traveling at 14 meters per second, a karate
expert's fist delivers a wallop of about 700 pounds into the target. In just 5 milliseconds,
he expends enough kilowatts to work a dozen electric toasters and his hand experiences
a deceleration of up to 400 Gs. And although bone can resist 40 times more stress than
concrete, on impact, the hand ceases to behave like a solid object and deforms as if it were
made of rubber. This is the original Massachusetts study. Marker dots on the knuckles show the
extent of that deformation and it's this in addition to the arm's ability to absorb shock
which ensures that it's the fist that breaks the concrete rather than vice versa. Those
karate studies were filmed here in the laboratory where so much of Dr. Edgerton's pioneering
high speed work was done and despite the fact that officially the professor retired 12 years
ago, he is still experimenting, unlocking the secrets of movement. No experiment seems
too mundane and today he and lecturer Charles Miller prepared a stretch time 200 times and
explore the high speed potential of a balloon filled with water. What would it look like
as it burst? Take one and Professor Edgerton waits for Charles Miller's cue.
Take two and a strategically placed drawing pin has been added to the scene. It's 50
years now since Professor Edgerton started answering the question, how will it look in
slow motion? True to form, it was only a matter of time before he asked himself, how will
it sound in slow motion? But 35 years ago, slow motion alarm clocks were the last things
on Professor Edgerton's mind. High speed photography was then playing a crucial role in unlocking
the evil beauty of nuclear detonations as they ripped apart the molecules of dry morning
air turning the desert sand to glass. Dozens of manned and unmanned cameras filming from
every conceivable angle were used to record flash, shock and blast effects. But because
of the intense brightness and the chilling speed of the event, no one had yet seen what
happens in the first few instants after what is called time zero. So Professor Edgerton
built a camera on top of a 75 foot tower seven miles away and recorded these eerie pictures.
This exposure taken less than a millionth of a second after detonation shows the bomb
enclosure florescing with radiation. A millionth of a second later, the bomb housing is vaporizing.
And instants after that, the nuclear fireball is beginning to grow, distorted at first by
the heavy materials in the detonating mechanism. As it expands at thousands of meters per second,
the temperature of the fireball reaches one million degrees, many times the temperature
of our sun. After another few millions of a second, the fireball is grown into a smooth
silent sphere that eats up the tower on which the bomb was placed and turns it into vapor.
It is now a 10,000th of a second after time zero. Although a still sequence such as this
is well beyond the exposure times and framing rates of cameras containing moving film, it
is still possible using a camera like this to obtain real moving sequences in which each
frame can be separated in time by less than a millionth of a second from its neighbor.
The trick is to hold the film stationary while a rapidly rotating mirror in the center of
the camera moves the image. The mirror rotates at up to 5,000 times a second, any faster
and it would explode. And as the image is swept around the inside of the camera, tiny
lenses focus the light onto each frame of film, producing a moving equivalent of several
million pictures per second. This is a spark plug at 4 million frames per second. Explosives
at 6 million frames per second. But here in the form in which it appeared on the original
strip of film 20 years ago is a sequence of photographs of a plasma physics experiment
which even at 8 million pictures per second was too slow to show the detail that scientists
wanted to see.
This is something that happened in the mid 1950s when there was a lot of work being carried
on on the subject of nuclear physics and rotating mirror cameras were providing a considerable
facility for the examination diagnostics of those experiments. And there were certain
records which were being taken with rotating mirror cameras which showed differences between
one frame and the next. Quite considerable differences in the shape of the plasma in
the experiment under investigation. And so it was necessary to develop cameras which
could run at very much higher framing rates than even the rotating mirror camera was capable
of. And this led us into the development of what are known as image tube cameras.
The time had come to leave optics and take a sideways step into electronics. For although
the lens on this camera is normal enough that's where the similarity ends. Behind the lens
at one end of the image tube there's a plate of material which emits electrons in response
to light. At the other there's a phosphor screen. Electrons have no mass and are easy
to deflect. So once you've focused your subject on the screen, in this case it's a detonator
cap. You can move the image electronically without the need for prisms or mirrors or
long strips of film to provide the framing rate you need. Photographed directly off that
phosphor screen here's the detonator cap exploding in under a millionth of a second. And here
a high-speed jet of liquid lead is ejected from an everyday air rifle pellet as it hits
a steel plate.
Those cameras will work at really surprisingly high speeds. We can in fact nowadays take
pictures at one million million pictures per second and such a camera, if it were running
for a second, would take enough film to go around the world twice. So of course we only
run them for a short time. But there we are looking at very very fast events and I think
probably the best example where we have to use the very fastest cameras today are on
these very very wonderful experiments where they are trying to harness the the energy
of the fusion reaction, the fusion bomb, the hydrogen bomb, to make electricity.
Only half jokingly that quest is referred to here as laboratory astrophysics. This is
the Laser Energetics Laboratory in Rochester, New York. And here they are attempting to
create mini-stars. Twenty-four lasers carrying, for the briefest instant, more power than
the total generating capacity of the United States are aimed at a tiny pellet of hydrogen
fuel like this to make it implode and raise its temperature to one hundred million degrees.
For one million million millionth of a second it will burn like our sun and this is what
it looks like. A micro view of the thermonuclear mechanics of a star snapped in a trillionth
of a second in the x-ray spectrum, color-coded to differentiate the enormous temperatures
and still it's too slow. Generally when you take a photograph such as
that one, that is an aggregate of events as short a time frame as that is, that is still
what is called an integral over time. The fundamental units of time, namely ten to the
minus twenty seconds for one over ten with twenty zeros, are units over which events
of single consequence take place and the ability to photograph those, to record those, to study
the building blocks that ultimately make up how matter behaves is a challenge that physicists
have sought for years. And if physicists do dismantle time and photograph
the individual building blocks of nature, how will that relate to the world we see unfolding
second by second around us? There are numerous models that describe the
behavior of Mother Nature, none of which we are sure in the limits are correct, but what
I am addressing now is the possibility to access in the extreme limit how Mother Nature
behaves and to record her behavior. That is very exciting.
When physicists are finally able to photograph events so brief that our everyday language
of space and time will be inadequate to describe them, what will the pictures look like? What
new wonders will they show?
Thank you very much.
Thank you very much.
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