♪♪ -Individual images can have great effects.

They can help reform our intuitions about the world around us.

-They ignite our imagination.

They make us ask the question, "What's that?"

They make us ask the question, "What if?"

They provide a way for us to grab onto an idea and go even farther.

♪♪ -Man's inventiveness seems to have no limits.

Using advanced technology, we have found ways to look at ourselves from afar and to capture images of the most remote galaxies in the universe.

-The same driving force has also made it possible for us to reproduce the inner world.

♪♪ -It's one of the most important photographs ever taken.

-They couldn't have built their model if they hadn't got structure 51.

-It's a literal photograph of the secret of life.

-This sketch is more or less the entire origin of species by natural selection in one little sketch.

-Back in the 1930s, everything was so simple.

Then this picture comes along and upsets the whole apple cart.

♪♪ ♪♪ ♪♪ -In the second part of this series on the most important images in the history of science, we turn our gaze inward.

We begin the journey into the world of the atom with a look inside the human body from the 16th century, long before X-rays and CT scans.

♪♪ -1543 has been described as an annus mirabilis, a year of miracles.

At the same time as Copernicus' book on the movement of the celestial bodies is published, another equally revolutionary book sees the light of day.

-The muscle man for the first time came in the "Fabrica" and are absolutely correctly designed.

This is absolutely new and first drawn in this book in the "Fabrica."

-"De Humani Corporis Fabrica" is written by Belgian anatomist Andreas Vesalius, and it contains something completely new -- images portraying the inside of the human body.

-Pictures are important because they visualize what the text means.

-As the images spread across the world, a 1,400-year-old conception of how the human body works is torn apart.

-Galen got wrong the physiology, for instance, of the kidney was completely wrong.

♪♪ ♪♪ -Antwerp, Belgium.

Medical students are completing the third day of their anatomy course.

In many ways, the dissections are carried out in the same way as they were 500 years ago.

-Vesalius showed exactly how corpses have to be dissected, what instruments have to be used for dissection.

Things that our students still continue in the same way.

-Andreas Vesalius grew up in Belgium.

But it was in Italy that he would forever change anatomical science.

-He arranged a sort of anatomical theater where the students could take their place.

And there in the middle was then a table where he had the corpse laid down on the table.

-Vesalius created the design for the first anatomical theaters, placing the students so they could see an open human body close up.

-This was absolutely new for the Renaissance.

So Vesalius innovated this principle for studies in medicine by giving the students the possibility to see really on the corpse what the different structures of the human body were.

Still, as I said, this 500 years later is done by the students in absolutely the same way.

-The foundations of anatomical science are laid in ancient Greece.

Galen is the most prominent anatomist of his time.

And his texts from the third century are the accepted reference work for 1,400 years, until young Vesalius turns everything upside-down.

♪♪ -In fact, when he still was a student in Paris, he went to the cemeteries and discovered old bones there.

When looking at the mandible, the jaw of the skull, he discovers that it was a bone in one piece.

And he studied the anatomy of Galen in which was designed that the mandible was in two pieces.

-Vesalius understands that there is something wrong with Galen's anatomical works when he takes a closer look at the human jawbone.

-As you see it here, see that he draws it really in one and only one piece.

So that made him think that there may be something that was not really true in the Galenic type of anatomy.

-And the jawbone was far from being the only error Vesalius found in the Greek texts.

There were other things that were not quite right.

-Well, what you see here, what Francis is demonstrating is the liver of a human being.

What Galen wrote down in his textbook was that the liver had five lobes.

And what actually Vesalius demonstrated is that it has only two lobes.

♪♪ The same goes through for the kidney.

Galen said that in the upper part of the kidney, there was sort of a membrane.

And when the blood came down through this membrane, the blood changed into urine.

Vesalius said this is not exact.

There is no membrane.

He dissected the kidney in the middle.

There he didn't see it.

-The reason for the numerous errors proved to have a surprising explanation.

-In fact, the Galenic anatomy was based on animal anatomy.

And practically all animals have a mandible bone in two pieces.

-Galen had never actually examined humans, only animals.

♪♪ -During 1,400 years, this anatomy was not changed.

So all people in the medieval time and in the beginning of the Renaissance accepted anatomy of Galen.

And it was Vesalius, by doing the dissections himself, that he discovered this was not really as Galen had proposed it in his texts.

-With the help of a large number of bodies and in conflict with the Catholic Church, Vesalius began to work on what would become the first modern book of anatomy.

♪♪ -He had dissections on man, dissections on women, even dissections on pregnant women.

Several of those corpses came out of the cemeteries.

♪♪ -Andreas Vesalius was the first anatomist whose work was based on a scientific method.

-If Vesalius was asked a question he could not answer the question, he went back to the body, dissected the body, found the facts, and then published it in a book.

That has never been done before, before Vesalius.

-But perhaps his greatest innovation was that he illustrated what he saw.

Together with German Jan Stephen, he compiled a series of images which showed the world for the first time what the human body really looked like.

-It's important because it is the first time that a medical doctor included a great number of pictures.

Before Vesalius, there were no such pictures in anatomy books, so this is the innovation that Vesalius made to anatomy.

♪♪ ♪♪ In the years to follow Vesalius, it was translated in practically all European languages and so dispersed to the surgical profession.

And all European universities accepted what we now call the Vesaliun anatomy.

This is the artery.

This is a valve.

-Even today, doctors and surgeons are astounded at the accuracy of the images.

-Everything is absolutely correct.

This is astonishing how the difference is between anatomical knowledge before Vesalius and after these pictures.

The difference is enormous.

It's incredible.

It's like a photograph, but 500 years old.

♪♪ ♪♪ ♪♪ -One human body part is more complex than the others and conceals so many secrets that there are still new important discoveries being made about how it works.

♪♪ -With its 100 billion neurons and 500 trillion synapses, the human brain is the most complex structure in the universe.

It is these brain cells which makes us the only animal to build enormous cities and ponder our own existence.

Spanish scientist Ramón y Cajal had depicted brain cells or neurons as early as 100 years ago, laying the groundwork for modern neuroscience.

-Yeah, Ramón y Cajal was a very important Spanish scientist.

And he wrote prolifically about how brain cells were organized with one another.

-But on one critical point, he was completely wrong.

-He made the statement that after birth, there were no new cells and that nothing could regenerate if it were damaged.

-In all the textbooks that followed, Cajal's conclusion was propagated.

You have only the brain cells you are born with.

It became one of neuroscience's most fundamental erroneous truths.

♪♪ ♪♪ To find out how one of neuroscience's most solid tenets began to crumble, we must pay a visit to a gated community for senior citizens in mainland Florida.

-You still want an answer why we like to live here?

Because people know nothing about science.

They are not interested in it.

And so we are sort of left alone and we can do our own things.

-From the outside, the Altmans' house doesn't look any different to other homes in the area.

-Let's go.

Let's go in the house.

In the house.

-But on the inside, it's apparent that you've come to two rather unusual retirees.

-Here's Joe's office right here.

-Two bedrooms have become workrooms.

And part of the garage has been converted into a small laboratory.

-And it's a workroom.

Work table.

And these are the specimens.

-In their archives, there are thousands of pictures of rat brains, thinly sliced samples that the couple has collected during more than 50 years of work.

-Oh, here's a beautiful one.

Oh, my.

There's the evidence.

There's another one.

I'll be darned.

So just in this section, there's at least two just gorgeous adult labeled granule cells.

-It was by happy coincidence that in Joseph Altman's MIT lab at the beginning of the 1960s, Ramón y Cajal's assumptions started to falter.

-I sort of was among others who pioneered this method of injecting animals with a radioactive amino acid.

And I had technical problems with that.

And so it occurred to me that why don't I use something called thymidine, which is a precursor of DNA.

And all the sudden, I look at them, my sections.

And I find that nerve cells are labeled.

-While working on something else, Joseph Altman stumbled across a remarkable discovery.

In the photo, neurons tagged with a radioactive substance could clearly be seen.

That meant that the neurons were newly formed.

Nothing strange about that, except that the brain was that of an adult animal.

-This has been described as the first demonstration of a neuron forming in the adult brain.

Each black dot is an electron that was captured by the photographic emulsion that we placed on top of the section.

-That picture.

-That picture.

Of course, I didn't believe what I was seeing.

And it took some time to demonstrate that indeed there are several regions in the brain where nerve cells are generated after birth.

There's no mistaking it's the generation of new neurons.

-This was from a post-natal brain.

So this is an adult animal that had been treated with this radioactive molecule.

So the suggestion was that that cell was born after birth.

And that was not how people saw the world at the time.

It was really quite extraordinary.

-Altman's finding punched holes in one of science's most established truths.

But it would be a long time, more than 30 years, before his discovery was widely accepted.

-We had been trained that all the brain cells that you are going to have as an adult came from before you were born.

So that was a hard biological question to grapple with.

The other problem was that we think of our -- We think of the brain as being the organ that identifies who we are.

It has our memories.

It has our personhood.

And if it's changing and growing, how do we retain a certain stability of self?

-Today, thousands of researchers work with Altman's discovery, now called adult neurogenesis.

-This is an example of adult neurogenesis at various time points in the adult brain.

Here at 14 days, they branch, and by 21 days, they are already beginning to make connections.

And they're still beautifully integrated within the circuit at 14 months.

-Today's researchers have access to technology which Joseph Altman, and to an even higher degree, Ramón y Cajal, could only dream about.

-For a scientist who had spent his entire life looking at static images, to be able to visualize the movement and dynamics of a cell even for me is just really amazing.

It's really exciting.

-Fred Gage has shown that neurogenesis occurs not only in rats, but also in the human brain.

And he has also shown that we can actually affect the formation of new brain cells.

Cages full of toys to explore -- so-called enriched environments stimulate neurogenesis in the rat brain.

-There are 300,000 granule cells in a dentate gyrus.

And with one month in enrichment, the number had increased to 350,000.

So 15% of the number of neurons increased in an animal just by virtue of the experience they had.

-And everything points to this also being the case with humans.

-This means that you can generate new neurons by what you do.

How you socialize, what you learn, what you experience can affect your brain.

So you are in fact in control of the structure and function of your own brain by virtue of what you do.

-Today the scientific community can look back at Joseph Altman's photo and declare that it heralded a coming revolution.

-I think that it's fair to say that Altman was a pioneer.

And it's always more difficult for the pioneers because they're out there alone fighting against dogma.

-It's a strange history, science.

Some people just cannot accept new findings.

Indeed, I myself didn't accept it initially.

I said it must be something wrong.

-But Joseph Altman doesn't regret that his groundbreaking discovery of 50 years ago didn't receive more attention than it did.

-In fact, in a sense I liked it because we were left alone.

And now I'm 87.

And I finally am free and I don't have to worry about neurogenesis.

Yeah.

Look at this flower.

-Beautiful flowers.

-Look at the birds flying.

♪♪ -It was at this country estate, Down House, south of London, that Charles Darwin worked out his theory of evolution, the idea of natural selection.

Of all these scientific discoveries made through the centuries, this is considered one of the most important.

-I think he liked the calm serenity of the house.

He wasn't terribly well a lot of the time.

And I think he liked the peace.

You can hear the blackbirds singing.

You know, it's a very peaceful environment, as well as the airplanes.

-Darwin lived in a religious time.

The established dogma was that all species were immutable, that their appearance and properties had been determined at the time of creation.

But there was doubt.

Fossils from an extinct, strange animal world suggested that not everything could be explained by the Holy Scriptures.

Darwin broke with the old notion of how life functioned.

His book "On the Origin of Species" exploded onto the scene in 1859.

But already 20 years earlier, he had manifested his revolutionary ideas in one of history's most important sketches.

-It's worth remembering that in 1837, the notion that things could change was completely unthought of.

And this diagram in some way invented the science of biology.

♪♪ ♪♪ -What I'm doing here is taking out some specimens from the voyage of the Beagle, some of the famous Galápagos finches actually collected by Darwin himself.

-During his journey around the world, Darwin became ever more convinced that species were not at all immutable.

The rich animal life on the Galápagos Islands became an important piece of the puzzle.

Darwin noted that the finches on the islands differed from one another.

Their beaks seemed to be adapted to different types of food.

It caused Darwin to start wondering what had caused the variations.

And he did write a little note in his "Voyage of the Beagle" book that maybe all these beak sizes, maybe you could think that they came from a single form.

-Back in England, he devoted all his time to the question.

-Well, this is Down House, where Darwin spent 40 years of his life.

He wrote his most famous book, "On the Origin of Species," in this very house.

-Here Darwin cultivated exotic plants and bred his own pigeons.

And in his notebooks, his bold idea began to take shape.

It is the middle of summer, 1837.

Darwin begins writing in notebook B.

The notebook contains his thoughts about what we today call evolution.

Just like the other notebooks, it is filled with text.

Page 36 also begins with a line of text, but then he breaks off and begins to draw instead.

-And it's a statement of the power of the image.

If you see this image as an evolutionist or even as a school boy or school girl, it's impossible not to realize what evolution is about.

-It's an idea taking shape not in words, but in a visual form.

And the fact that it says at top "I think," I just can't explain it in words.

And the picture is saying a thousand words at that point.

-The picture which emerges show the principle of how all life on earth works and instantaneously sums up our planet's four billion years of evolution.

♪♪ ♪♪ -So what we've got here are a series of branches on this family tree.

A, B, C, and D. And B and C are close relatives, a bit less related to D, which is further away, and less related again to A.

Okay?

But relatedness means having a shared ancestor, and there it is, 1, at the base of the tree.

And Darwin dared to think in 1837 that this common ancestor, 1, at the root of the tree might be something that lived in the past that's extinct that he might have found as a fossil.

So that in this diagram springs immediately the whole idea of evolution.

-Animals and plants evolve due to changes in the environment in which they live.

The less well-adapted animals die.

And if enough die out, an entire species can disappear.

The more well-adapted survive and pass on their traits to the next generation.

In this way, with time, new species spring up.

For example, the different types of Galápagos finches.

-The different species of finches were accessing different food.

And so you see a very nice example of evolution where the large-beaked ground finches were able to crack the big nuts.

And the smaller-beaked birds were better at eating the fleshy fruit.

And what he says in the text here, that A and B are different from each other, but B and C are more closely related.

So you have a similar sort of story, really, if you like, with the finches.

That these two are the equivalent of the B and C. So you can see the gradation of speciation.

-Darwin's theory was brilliant.

Natural selection explained how new species are formed and why they can become extinct.

And it suggested the unspeakable, namely that all living creatures had a common ancestor.

-When "The Origin" came out, it caused an uproar, first of all, in the scientific world.

And it did.

There is no question of it.

And second and more interesting in the world of religion.

-Because we realized that, of course, we fit in with this as well.

We're not unique.

We are part of the animal kingdom.

-Darwin's critics called him the most dangerous man in England because if his theory of evolution was correct, then the Bible was false.

-I think he was very nervous of the whole idea.

I mean, at one stage, he wrote, "It's like confessing to a murder."

I mean, I think he felt nervous about it.

-The church finding it difficult to reconcile itself to Darwin's book was one thing.

But even his colleagues were skeptical.

They wanted proof.

-One of the key things that Darwin's ideas needed was these kind of in-between stages, evidence where something is sharing features.

And that was archaeopteryx.

-Darwin was lucky.

Only two years later, an ancient imprint was discovered in the bedrock left by a strange creature which gave credence to Darwin's ideas.

-If the limestone hadn't preserved the feathers, it would just probably be seen as a slightly odd little light-boned reptile.

But because it's got the feathers, it becomes this extraordinary key piece of evidence.

-And I think the discovery of that kind of fossil, which was somehow intermediate between two living groups, dinosaurs and birds, was very persuasive.

And there Darwin, I think, was convinced himself of the power of his theory.

♪♪ ♪♪ ♪♪ -What Darwin didn't have a clue about and what would take another hundred years to be understood was which biological process governed evolution.

-Today, every school child recognizes the coiled double helix that contains the blueprint for all living things.

But still in the 1950s, the molecule's appearance was a complete mystery.

-This was, you know, this was the obvious problem to crack.

And there were several groups across the world, at least three major ones, who were trying to crack it.

-The group which made perhaps the greatest effort to crack the structure of the DNA molecule was the Cambridge group led by Francis Crick and James Watson.

-Watson, who was very, very young, really, he knew that this was the way to learn Swedish, to get the Nobel Prize, was to discovery the structure of DNA.

And they were pretty damned ruthless in their behavior.

-Watson and Crick won the race, but it was thanks to a photo taken by a competing team of researchers which put them on the track to the solution.

-It was taken at King's College London by Ray Gosling and Rosalind Franklin.

And it just shows what nobody had realized before, that inside the molecule of DNA, there's two identical sides that can come apart and copy themselves.

And that is the secret of life.

♪♪ ♪♪ -Oh, look.

He's got my T-shirt on.

The number of times that bloody thing's been reproduced.

If I only got a penny for every time, I'd be a rich man.

Golly.

Yeah.

-It was this man, together with his colleague Rosalind Franklin, who took the famous photo 51, considered by many to be the single most important photograph in the history of science.

-Now, this is the way Rosalind Franklin would have walked when she came back from lunch.

So where do you want us to go now?

-We're going to the lab that you worked in.

-Okay.

-It's been many years since Raymond Gosling visited his old workplace where he spent countless hours.

♪♪ -So this is where you did the work?

-This is not where we worked.

No.

-It isn't?

-No.

-That's good.

-King's College was an enterprising place to be in the late 1940s.

New Zealander Maurice Wilkins, who would eventually share the Nobel Prize with Watson and Crick, was here as well as a young Raymond Gosling.

-Yes.

Yes.

We found it.

Hurray.

It's nice to be standing here.

So it's 62 years ago.

That's a lifetime.

♪♪ -King's College was using X-ray crystallography to pinpoint the carrier of the genetic information.

And Gosling had managed to portray one of the prime suspects, DNA.

-And that was the only eureka moment of my life because I realized that meant that if DNA was truly the gene material, then I'd just shown that genes could crystallize.

-In order to expedite the work, one of the world's leading experts in the field, Rosalind Franklin, was employed.

-She showed that if you could control the humidity, the water content of the atmosphere around a specimen and therefore the water content in the fiber, you could actually get two ordered structures, which she called structure A and structure B.

-When Franklin increases the humidity, the DNA molecule changes shape.

It contracts.

And this will result in the photograph that solves the mystery of the molecule.

If you raise the humidity to 92%, you get structure B, which is the thing that excites interest these days because it's known as photo 51.

♪♪ And that was the best diffraction pattern that I ever got.

That's it.

You got it.

That's structure B.

Isn't it beautiful?

Yes, that's it.

That's photo 51.

I was pretty cock-a-hoop, I can tell you.

That's what happened.

It was bloody marvelous.

-What you do is you shine a very powerful X-ray beam onto a tiny molecule.

The molecule scatters the energy of the X-ray.

And that scattering process is picked up on a sensitive film.

-Both Franklin and Gosling understand that they have found an important piece of the puzzle.

But truth be told, at this point, they don't know how to interpret their own picture.

-Here we've got this kind of crisscross.

Is it a blob?

Is it a circle?

Are there two parallel lines?

Nobody could really understand.

-But Cambridge researchers Francis Crick and James Watson do once they mysteriously get their hands on the photo.

On January 30, 1953, Watson travels to London.

He suspects a third team, led by Linus Pauling at Caltech, is close to solving the mystery and suggests a collaboration with King's College.

Franklin declines the offer, but without her knowledge, Watson receives a copy of photo 51 from Franklin's colleague Wilkins.

-And when Watson saw this picture of the crosses, he says his jaw dropped.

-It didn't take long for the Cambridge researchers to see the molecule's real face.

-They had that sudden flash of inspiration, almost Leonardo-like flash of inspiration, where you see what the truth is behind the image.

-And what Watson saw was that specific pairing was identical.

If you turned it round the other way, they were the same.

So all of the bases met in the middle.

-The diffraction pattern in the photo showed not only that the molecule really was helical, but also that it was a double helix with anti-parallel strands where the base pairs, which are the code for inheritance, were on the inside of the helix.

-He realized this is how the molecules came apart, replicated themselves.

So then he ran back to Cambridge and told Crick.

They came out with their famous paper.

-And once that genie was out of the bottle, Rosalind and I, we looked at our cylindrical patterns and we saw evidence.

Everything screamed double helix.

-Watson and Crick received the Nobel Prize in 1962.

Rosalind Franklin was never considered for the prize as she had died of ovarian cancer four years earlier.

Neither was her colleague, Raymond Gosling, the man who actually took the important photo.

-That's the question that I've been asked all my life.

How come that you didn't get there before them?

We would have got there.

Might have been two or three months, but it might have been two or three years.

They couldn't have built their model if they hadn't got all of the information from this structure 51.

♪♪ That's photo 51.

And that's what photo 51 looked like when I developed it.

♪♪ ♪♪ -Few may have believed that the very building blocks of matter could be witnessed.

Atoms are so small that they are measured on the minuscule scale of nanometers.

But they actually can.

-When I was in school, I literally learned that you cannot see single atoms.

I remember quite literally that my teacher was saying you can't see single atoms.

-This picture of the name of a famous computer company proved that it's even possible to grab hold of the molecules and move them one by one.

-First thing it came as kind of an accident.

My goal did not include being able to manipulate atoms.

It was seeing that these atoms would sometimes move when we operated the microscope incorrectly.

I said "Wait a second.

We can get that under control."

-Writing "IBM" was an incredibly smart move for Don as a scientist and as a business person.

Right?

I mean, what else would you write?

I mean, you write the letters of the person who funds you.

Right?

That's perfect.

-This is really the very bottom of what we believe would be mankind's ability to ever build anything.

And it was much smaller than anything anybody had ever done before.

♪♪ ♪♪ -The man responsible for the picture lives high in the mountains above Santa Cruz, California.

-Oh, this is about 17 nanometers from here to here.

-At the end of the 1980s, Don Eigler found a way to physically grab hold of the atoms.

-You know, we could get this atom to jump between the tip of the microscope and the underlying surface just by applying a voltage pulse.

We'd put on a polarity in one direction, and the atom goes from the surface to the tip.

And you reverse the polarity of the voltage pulse and the atom goes from the tip back to the surface.

That can be used for information storage.

You could represent a logical one or zero.

It could be one bit of information.

The other thing that has proven to be much more important is the ability to pick up an atom and carry it some other place and put it back down again.

-Now, what Don pioneered here, he was able to use this tool for moving atoms.

So if I take the needle and just bring it closer to this atom here, then I can exert a force on this atom.

I can move this atom along the surface following the tip.

This is done in this little model with magnets in here.

In reality, that's just the chemistry, that either atoms like each other, then you have an attractive force.

Or they don't like each other and they repel each other.

-This is the machine that Eigler worked with.

And here his younger colleagues continue to explore the world of the atom.

-Every once in a while we'll come to the lab and we'll go, like, "Wow, this is really crazy."

You sit here and then you think there's an atom or molecule sitting over there in this room next door.

You know, and I'm tweaking it.

That's truly amazing.

-The idea of an atomic world dates back to the ancient Greeks.

But it isn't until the 17th century that the journey to the inner universe begins.

Anton van Leeuwenhoek makes high-quality magnifying loupes.

And in the monumental "Micrographia" from 1665, Robert Hooke depicts a hitherto unknown micro-world.

In the 1930s, Ernst Ruska's electron microscope makes it possible to portray structures as small as a micrometer.

And these are the very first pictures where individual atoms can be seen.

In this case, copper atoms.

Today, the most powerful microscopes are these, scanning tunneling microscopes.

-Don now is known for being the first person to move atoms.

He built a machine that was totally unique at the time.

The stability that he needed to make this possible is all in just some fantastic engineering.

-The microscope is placed in a vacuum to avoid contamination and at temperatures nearing absolute zero because it is only at extremely low temperatures that atoms move slowly enough to be captured.

-So what was special about this was the low-temperature aspect of the microscope plus clean surfaces.

And that made it so we could work with atoms that were stuck to the surface but not stuck too strongly.

And that was the key.

-Don Eigler clearly remembers taking his famous photo in November 1989.

-Well, there were days' worth of preparation, of getting the vacuum good, getting down to low temperature.

And then came the difficult part.

We had this nickel surface.

-He sprayed xenon atoms on a nickel-plated surface and then started painstakingly arranging the atoms.

-Then we used the tip of the tunneling microscope to gently drag each individual xenon atom around.

-The entire process took 22 hours.

And it wasn't easy getting the atoms to behave as he wanted.

I started writing the M over here.

And then I made a mistake.

And I made many of these atoms move around to the wrong locations.

I'm trying to move this atom and the atom won't move.

And I change things and I try again.

And it won't move.

And I try again.

And after a while you develop a sort of personal relationship with that very stubborn atom that will not move.

♪♪ Nowadays, it's just like drag and drop on the computer.

We could probably write out this in 15 minutes.

-This was completely revolutionary.

At the point, nobody had actually positioned a single atom with any -- with this level of control at all.

And it completely blew away everybody in the science community.

-Going in by hand and manipulating the letters "IBM," you know, was this incredible feat that maybe it had no practical purpose other than to galvanize the imagination of countless, you know, now generations of graduate students and post-docs and scientists to know that it's now possible.

We're in the era where we can atomically assemble structures.

-In some ways, the photo marks the start of a whole new field of research.

-And when we think about nanotechnology, we're thinking about building things up atom by atom.

And so this is the first time that people assembled with atomic precision any sort of coherent structures.

-The means to capture, move, and organize individual atoms is the holy grail of nanotechnology.

-When you can put atoms where you want them to go, you can build entirely new structures.

At first it will be letters like Don Eigler and his colleagues assembled first.

Then it will be, you know, small molecules.

And then in the future it will be little machines, little robots, things that can actually have, you know, great benefit to humankind.

♪♪ ♪♪ -Atoms are not the smallest component of matter.

There is an even smaller world inside the atom.

And that world too is one we can visit.

-Take an object -- a rock, a stick -- and break it.

Then break it again.

How small a fragment can you make?

Is there any limit?

-All atoms are formed by the same thing -- particles.

Electrons with their negative charge were discovered by the end of the 19th century.

They were found to revolve around a core of positively charged protons.

And at the beginning of the 1930s, it was shown that the core also contained neutrons.

-Back in the 1930s, everything was so simple.

The universe consisted of electrons, protons, and a new particular called a neutron.

Then this picture comes along and upsets the whole apple cart.

-There have been several instances where a single image has upset the received ideas of how things worked.

And physicists sometimes refer to these as golden events.

This would be a golden event.

A particular instance that was so remarkably clear and persuasive that it served to change how people saw things.

♪♪ -This is a particle accelerator.

It is an experimental tools that scientists use to gather knowledge of high-energy particle physics.

-The subatomic world cannot be photographed, but we know that it's there.

Thanks to accelerators such as the LHC in Geneva, we know that it is absolutely teeming with particles.

To find the starting point of this particle hunt, we have to go back to the beginning of the 1930s and to the little University of Caltech in the desert outside of Los Angeles.

-Caltech was designed to be a new kind of campus, a science-based campus.

-The university grew into a learning metropolis in large part thanks to Robert Millikan.

-Robert Millikan.

A great scientist.

Something of a publicity hound.

He loved to pursue very dramatic-sounding programs.

But he'd also done some very important science.

But then Millikan came across an idea.

He came to believe that in interstellar space, atoms were forming.

-Millikan imagined that atoms were forming in the vacuum of space through the fusion of protons and that the process resulted in radiation.

-People knew that there was some kind of radiation coming from deep space.

And Millikan tried to pursue a theory that was accepted by practically nobody but him and his immediate collaborators.

♪♪ -When he and Carl Anderson were here, this was not part of the campus.

So we're moving from some new buildings to some older buildings.

-In order to study the mysterious cosmic rays, Millikan employed 25-year-old Carl Anderson.

-He was a student of Millikan.

And then Millikan asked him to stay one more year.

And it was during the one more year sort of fateful time that he made this discovery.

And the reason that Anderson had to do his experimental work here is because he needed a lot of electricity to run his magnet.

And that was available in this building.

-In order to capture the cosmic particles, Anderson created a strong magnetic field around a so-called cloud chamber.

A cloud chamber is a glass vessel filled with super-saturated water vapor, which captures trails of particles passing through it.

♪♪ -So this is typical of what his lab might have been located and what it might have contained.

So it was pretty bare-bones, but a lot of important work.

-It quickly became apparent that the machine was well-constructed.

Anderson captured several images showing visible particle tracks.

But the images also caused problems.

-He found some particles that he interpreted as going up and being positive.

And Millikan said that's impossible.

You can't have up-going particles.

-Some of the particles behaved in a way neither Anderson nor Millikan expected.

They had the mass of an electron, but in the magnetic field, they didn't move in the direction that a negatively charged particle should.

Rather, they moved in the opposite direction.

-Anderson said "Okay, well, I'll build a cloud chamber with a little piece of lead across it.

And then the charged particle will lose energy as it goes across and we'll know which way it was traveling.

We'll resolve this argument that we're having."

-The lead plate would cause the particles to slow down, making it easier to see how they were actually moving in the magnetic field.

-On August 2, 1932, he photographed this plate.

Was plate number 75.

And he published an article with this.

And he said there's something new in the world.

-The 75th exposure with the lead plate in place proved beyond all doubt that Robert Millikan's theory was completely wrong.

-Everything about the setup was designed to check a theory that eventually was completely discarded.

And instead this image led to the creation of a very different episode in the history of science.

-Anderson had discovered a whole new type of matter.

♪♪ -This is evidence of antimatter.

Bingo.

Positively charged electrons, which violated everything we thought about matter.

-Every particle has what is called an anti-particle, a twin with the opposite electric charge and the same mass.

-Carl Anderson's picture showed for the first time the paradoxical anti-world around us.

-For every particle, there's an anti-particle.

There's an anti-electron.

There's anti-proton.

An anti-neutron.

-And when anti particles meet their mirror particles, they both annihilate.

The positively charged electron which Anderson captured on film became known as the positron.

And it started a particle craze which continues to this day.

-And now the floodgates have opened.

-The list of particles is long, and probably not all of them have been found as yet.

-Not long after that began the floodwaters of new particles that were discovered in the period after World War II.

Pions and all sorts of other particles that became what's called the subatomic zoo.

-Several groundbreaking images have been captured within particle physics, but none of them changed the playing field as radically as the positron.

-We have to remember how extraordinary it was back in 1932 to be able to say "Here's a picture.

And on the basis of this single event, we can say that there's a new form of matter in the universe."

♪♪ ♪♪ -And here, in the world of the atom, the journey ends.

To delve even deeper into matter requires technology that does not yet exist.

-I don't think we're going to be able to see into the interior of atoms unless we can come up with microscopes which image both in space and in time.

Now, we've taken steps in this direction.

-It will be up to the next generation of scientists to continue the journey into the core of the atom and to attempt to depict it.

♪♪ If they succeed, the images will fill up another page in the great photo album of the history of science.

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