"The human eye, one of the most powerful instruments on Earth." "On a clear day, we can spot the smallest detail in the widest view." "But what the eye sees is not the full picture." "Alongside the world we see is a very different world." "An invisible world of hidden forces and powers." "That shapes every aspect of life on Earth." "Now technology can open a door on that hidden world, revealing its mysteries and showing us the true wonder of the world we live in." "Sunday morning in the heart of town." "This square looks pretty calm and quiet, but it's not." "The place is alive, it's teeming with activity." "Our world stops there." "The eye of a needle held at arm's length is pretty much the limit of human vision." "Anything smaller is invisible." "But that doesn't mean it isn't there." "Beyond the limits of our eyes there's an amazing microworld." "A world of such power, it shapes our whole planet." "Take these things, microchips." "These days they're inside half the stuff we own and as the technology moves on, they're being made smaller and smaller." "But by entering the invisible microworld, we can manufacture on a mind-bogglingly tiny scale." "Engineering is going molecular." "Everything that exists is made up of atoms." "Its properties depend upon how those atoms are arranged." "If you rearrange the atoms in coal, you get diamond." "But manufacturing is very crude at the atomic level." "It's like playing with Lego, but with gloves on." "Nanotechnology is finally allowing us to take the gloves off and it's going to revolutionise our world." "This is a factory of the future." "It operates at a scale so miniscule that even the smallest speck of dirt could ruin everything." "Which is why I've got to dress up like a cartoon sperm." "Now, I'm all for cleanliness." "If I turn up at somebody's house," "I might wipe my feet before walking in." "But here through those doors is a world where cleanliness takes on a whole new meaning." "If I take a single speck of dust in there," "I'd be as popular as if I'd walked a pig farm into someone's brand new carpet." "The machines in here allow engineering on a barely imaginable scale." "For some of their work, they need Britain's most powerful microscope just to see what they're doing, it really is that small." "So, how small can I go?" "Here's the plan." "What I'm going to try and do is etch the title of this series on to an area 100 times narrower than the width of a single hair." "We put a strand of my hair in the machine." "There it is." "I'm looking for a good spot." "Big enough to write 'Invisible World' onto." "We're going to work on just one section, on one scale of a single strand of human hair." "That's a platelet of hair." "That is mind-blowing." "Type in a..." "Invisible Worlds!" "It's weird, because what I'm about to start is very small, and yet I feel like it's a very big moment." "OK, here we go." "Oh, my God!" "There it is." "That's astonishing." "In an instant the machine has carved away just a few hundred atoms to form the words." "So, just to get an idea of how tiny it is, that's tiny on the width of a piece of hair." "It's about half a micron wide." "A hair is at least 50 microns wide." "It's incredibly tiny." "So that's the title of this series written on a tiny piece across the width of this hair." "And in fact each of these letters is about maybe 1,000 atoms wide." "To put that into context, if I were to write every letter of every word of every page of every book in your average library, at that scale I could fit the entire collection on the end of this pen." "That's very, very small and very, very clever." "Of course, there isn't really all that much call for an entire library on the end of a pen, but engineering on this tiny scale could bring medical breakthroughs and a manufacturing revolution." "And is letting us mimic some of nature's extraordinary micro-designs." "Nature has had hundreds of millions of years to perfect her designs, but now with machines like those in there, we might be able to copy them." "Just think of the amazing possibilities, some of the incredible things you see in nature might finally be within our grasp." "You might think the massive machinery of the space programme would have little need to copy nature's miniature marvels." "But harnessing the microscopic world is helping NASA tackle one of its biggest problems." "Dust." "Yep, dust." "The first thing we did was to set up the American flag on a pole and this is a picture of me taken by Alan Shepard." "And you can see I've only been out just a few minutes and the dust is starting to already accumulate below the knee on the space suit." "And the longer you're out, the more you accumulate." "Mitchell and Shepard hiked three miles across the moon, further than any other astronauts." "And like all Apollo missions, they discovered that space dust isn't like dust on Earth." "With no atmosphere to smooth it, it turns out to be fine as flour, but rough as sandpaper." "Abrasive and jagged, it cuts through fabrics, clogs up machinery and even punctures air seals." "Which is bad." "It was causing problems for breathing and clogging up vent systems and air conditioning systems." "It was impossible to get off." "NASA has spent years searching for a solution to this dusty problem and now they think they've found one." "Here back on Earth." "Specifically in lakes, riverbanks and forests." "And if you want to be really specific, it's deep in the invisible microworld of a lotus leaf." "Instead of trying to create something new, we said the best place to start is nature." "So what we started doing was looking at the lotus leaf." "Dr Wanda Peters leads a team at NASA's Goddard Space Flight Center looking into a special property of this amazing leaf." "If you look at a lotus leaf with just your visible eyes, it just looks like any other leaf." "It's a nice green, it looks like a waxy exterior." "But in one respect, this leaf is unique." "The lotus leaf just doesn't get dirty." "Nothing can stick to its surface." "Water just rolls off and it takes any dirt with it." "The secret of its astonishing self-cleaning act lies far beyond our normal vision." "The structure that's going zig-zagged across, that's one of the veins in the leaf." "You can see that with your naked eye." "But when you increase the magnification, you have spots that you see actually protruding out of the surface of the leaf." "The human hair is about 60 microns, so that's about this wide." "Keep zooming in on the leaf and you can see just how intricate nature's design really is." "The peaks and valleys are themselves covered in tiny hairs." "When you're just looking at a lotus leaf with the naked eye, you would never believe that you would see a surface looking that smooth that can actually be that rough." "The hairs of a lotus leaf's surface keep water and dirt suspended above it." "Less than 1% of this water droplet actually touches the leaf." "Its natural self-cleaning ability has inspired NASA's team to try to replicate it." "To show us what they've achieved," "Wanda has put on some special NASA gloves." "And they're about to test them." "She's treated one of these tiles with a coating based on the microscopic rough texture of the lotus leaf." "If you look at them side by side, there's really no difference between the coated surface and uncoated surface." "So, to the dust test." "The untreated tile." "And look at that." "The treated tile just shrugs off dust." "'Three." "Two." "One.'" "Now NASA is developing a stay-clean solution that could be applied to everything from the astronauts' suits to the shuttle itself." "And the lotus leaf secret isn't just for space." "Many of the inventions spearheaded by NASA - think Velcro, Teflon - have eventually made their way from space back down here where they've revolutionised our world." "The lotus leaf coating looks set to be no exception." "Watch this." "It absolutely flies off." "Look." "That's astonishing." "I should be soaked." "I mean, look at that!" "I could pour water on it all day and it just runs off, it makes no difference." "But it gets better." "Almost any surface could be coated like this, protecting us not just from a light soaking, but also from bacteria." "The lotus leaf is just one example of nature's microscopic marvels." "All around us nature has harnessed this invisible world to do truly remarkable things." "We're all used to keeping our feet on the ground." "But wouldn't it be great if we could defy gravity?" "What I'm doing right now is pretty amazing." "It wouldn't be possible without an army of helpers." "Wouldn't it be great if we could do this for real with absolutely no outside assistance?" "Well, there is an animal who can." "The gecko." "It can run up vertical surfaces and across ceilings and the secret to how it can do that is hidden in the microworld of the invisible." "So just how does the gecko defy gravity?" "He may look like your average lizard - five inches long, scaly skin, all the usual lizard staff." "But there's nothing ordinary about his ability to cling tightly to any surface." "Pressed against a sheet of glass, his toes are splayed out to give maximum grip." "Each of them is no bigger than a fingernail." "But what exactly is it that's holding them on?" "Could it be the claws?" "It's puzzled scientists for years." "But it turns out scientists weren't looking closely enough." "On each tiny toe, there are a dozen parallel ridges, each with a soft velvet-like surface." "Microscopic photography reveals that the surface transforms into hundreds of thousands of tiny hairs." "But move in closer still, and they reveal a quite astonishing phenomenon." "At 100,000 times' magnification, suddenly you can see that each of these half-million hairs has itself split ends at the tip, which create even finer hairs." "10 million could fit on a pinhead." "And that's the secret." "The gecko has created a vast area in contact with the surface of the glass." "It's all to do with something called van der Waals force." "At the micro level this force pulls molecules together, a bit like magnets." "And the bigger the surface area, the greater the attraction." "It's a very weak bond over a single hair, but multiplied by 10 million or more and it's incredibly strong." "So strong it can take 10 times the gecko's body weight to prise the animal off a surface." "And in fact, the gecko has had to develop a unique toe-curling method to unstick himself time and time again." "We all know small is beautiful." "It turns out it can be really rather clever as well and it's only when we drop into the world of the invisible that we realise just how awesome some of the things we take for granted really are." "The Humber Bridge, completed in 1981, it's one of the longest single span suspension bridges in the world." "But if you think the bridge is a masterpiece of structural engineering, then up here you'll find an engineering miracle." "The spider's web, unchanged in over 100 million years, and one of nature's most successful designs." "I don't particularly like spiders and therefore by association spider's webs either." "But get past that and speed things up and suddenly we're watching a master architect at work." "First he uses one type of silk to spin a cross and connect the primary strands of the web, creating the spokes." "That's what gives the structure strength." "Next he turns back on himself and uses a different type of silk, a particularly sticky type of silk, to spin the lethal trap for any insect that touches it." "Job done, a free zone is left at the hub and now he sits and waits." "Researchers the world over are trying to discover the microscopic secrets of a spider's web." "OK." "What I'm doing now is purely in the interests of science, really not because I want to." "'To study one, first you've got to catch one.'" "OK." "Urgh!" "Right, good." "It's lovely, I like it." "So..." "Ohh..." "Right." "This is a nightmare." "I'm in a greenhouse full of spiders' webs." "Ohhh!" "OK." "She's moving." "She's definitely moving." "Ah!" "Ah!" "She's moved!" "OK, a simple act, just in, catch." "What's the best holiday you've ever been on?" "This is it, going in." "Let's not make a big thing about it." "Tom." "This is actually the tough role in this job." "Oh, God!" "Oh!" "Yeah, I could have done that." "I could have done that." "We've got her and I bet you were glad I was here to help." "Let's go out now." "Do you want to open the door?" "OK, thank you." "Go, go." "Now we've caught our spider, the next step is to..." "Um, milk it apparently." "I'm just going to pin one down next to her." "You're not harming her?" "Absolutely not." "Then I just pin the other one to constrain her." "Now I've never actually milked a spider before, funnily enough." "Still, always a first time." "What I have to do now is grasp this little thread, which is extending out of the back of her abdomen and pull." "Simple as that." "And out comes a seemingly endless thread being made in the tiny silk factory at the back of the spider." "This spider could produce 700 metres of silk in one continuous strand." "But to discover why the silk is so strong, we need to have a closer look at the spider itself." "This is the actual spider at 12,000 times' magnification." "Here on the abdomen are four organs known as spinnerets." "Each of them is dotted with lots of mobile finger-like spigots." "They squirt out liquid protein." "As the liquid leaves the spider... ..It dries on contact with the air, forming a super-strong thread." "And twisting several strands together gives the thread even more strength." "Each spider can produce several different types of silk from their spinnerets." "From sticky sheets used to wrap the victim... ..to an incredibly strong single thread." "You're kind of aware of the toughness of this stuff that's just disproportionate to its scale." "It's so fine." "That's a thirtieth the thickness of human hair." "And yet you can feel it, you can exert pressure on it, you can feel the bounce in it." "If this thread were as thick as a pencil, it could tow an ocean liner with ease." "But the genius of the web lies not just in the strong thread, but in how it's used." "And that secret lies in the water droplets at every junction." "Inside each droplet, strands of web are tightly curled." "Scientists believe that when a fly slams into it... ..These strands unravel, allowing the web to flex and stretch." "Without breaking." "We've already learnt from some of the spider's tricks." "But now we're going even further, harnessing the microscopic secrets of the natural world to design completely new, man-made structures..." "..Capable of withstanding the most powerful forces... ..As I'm about to demonstrate with a large piece of fruit." "That is a watermelon." "And this is a Glock 17, a 9mm semi-automatic pistol." "It can fire rounds at up to 300 metres a second." "It really is no match." "Well, that was hardly a surprise." "For your average melon to stand any chance against a bullet like that, it's going to need some serious protection." "Something like this, made of aramid, a very strong but lightweight material that has become standard issue body armour for police, military and now watermelons." "The bullet is travelling at over 600 miles an hour." "But on impact, the thin fibres in the jacket are so strong and densely woven, they spread the energy." "Good news for Mr Melon." "It stopped the bullet." "I can feel it." "Ah." "Yeah." "Still not a good day for the melon." "Clearly, even more protection wouldn't go amiss." "And the microscopic world might have the answer." "In, of all things, this puff of smoke." "Except this isn't really smoke." "It's actually minute strands of the strongest fibre on Earth." "This man-made carbon thread is five times thinner than a human hair." "But ten times stronger than steel." "Each tiny thread is made up of thousands of even finer strands." "And each of those is made of thousands of yet smaller strands." "In fact, every single fibre is built from more than a million tubes of carbon, just one atom thick." "And it's unbelievably strong." "Here's the new fibre, pitted against the world's current strength champion in a special testing machine." "Subjected to a massive force... ..The aramid finally gives out." "But the carbon nanotube goes on and on." "It's more than three time stronger than the aramid." "It's still a prototype at the moment, but it promises to revolutionise our world." "In our busy world, we are blissfully unaware of the vast universe of creatures living alongside us, but invisible." "Take this chap." "About to cook a romantic dinner." "A dinner just for two." "At least, that's what they think." "Mmm!" "Move past our human scale into the microworld... ..And this date is actually pretty crowded." "Even when you think you're alone, in fact, you've got company." "A universe of other creatures that we never see." "Like the tardigrade." "They're the size of a small grain of sand." "Completely transparent." "And they're everywhere." "Massively outnumbering the entire human population." "And there are creatures lurking in your dinner, too." "BOTH:" "Cheers." "The fresh leaf salad, for example." "Drizzled with vinegar dressing." "Complete with a dash of... ..the free swimming vinegar eel." "Yes, it's less than a millimetre long, but it's probably best not to think about it too much." "And then we come to the cheese course." "Dusted with a coating of cheese mites." "You know that fine grade dust you can make out on older cheese?" "That's the bits the mites leave behind when they're done." "These mites are often deliberately added to give cheese its fine flavour." "But it's not just our food that hosts a thriving micro-life." "In every room, we're totally surrounded." "By creatures who share our most intimate moments." "If not necessarily our love of Barry White." "These are dust mites." "One square metre of rug can contain as many as 100,000 of them." "But we need them." "Feasting on our skin flakes, they help to break down debris." "We might think we are alone in our homes, but in fact we are part of a massive ecosystem..." "..Teeming with useful life." "Yes, all right, put her down now." "Looking into the microscopic, we can see what helps us, but also what might kill us." "The difference between stability and chaos can pivot on changes to the tiniest structures." "Even the microscopic can release the most powerful forces on earth." "Dany Kistler and the rescue dog team in Davos, Switzerland, know all about the danger of getting caught in an avalanche." "The avalanche came just out of nothing." "They came over a cliff and was just falling on me." "It's super quick." "The snow brings you in." "And then it starts a whole washing machine." "It's like somebody with hammers on you, bam!" "Bam!" "Bam!" "You're covered and you've got no idea what's going on." "The avalanche stops." "You're like in concrete." "And you're not able to move one finger." "Nothing." "But where does the power of an avalanche really come from?" "The answer lies deep in the microscopic world, way beyond what we can normally see." "Using specialist probes, scientists are only now beginning to understand the potentially lethal power... of a snowflake." "We all know the classic snowflake shape." "But once snowflakes land, they change shape, losing their delicate arms and bonding together." "It's far too small for us to see normally." "But these microscope shots show actual snowflakes that have formed a powerful bond, locking the snow crystals together." "This creates a secure snow pack." "But it takes just one, microscopic change deep below the surface... ..to turn this snow pack into a white time bomb." "A sunny day followed by a particularly cold night causes tiny, but important changes in the pack." "The snow crystals melt, then resolidify." "But as they do, they form a different, more angular shape." "Their bond is now weak and traps air between the crystals." "They form a loose, lattice structure." "Deep in the snow, there's now a weak layer." "Only a few millimetres thick, but enough to make the slope treacherously unstable." "The most dangerous part is, you can't see the risk." "You can't see the instability of the snow layer." "It is like a white, big sleeping monster." "This probe allows scientists to detect these dangerous, microscopic changes." "By 30cm down, the signal decreases and there might be a weak layer down there." "If the weak layer's there, it could give at any time." "The final trigger could be a wild animal, a skier, or something as simple as just the right amount of snow." "If you hit one of these weak layers, it will crack and the whole face will start to slide." "They are absolutely invisible." "Beneath the surface, the weak layer fails." "The bonds holding it to the layer above break." "And an avalanche starts." "Before you know it, 30,000 tons of snow is thundering down the hillside." "Within 10 seconds, it reaches 200km an hour." "This massive, destructive power is triggered by a microscopic change in a tiny snow crystal." "But it's not only nature that can generate huge forces at the microscopic level." "Down here, there's a miracle of engineering on display." "It's got thousands of moving parts and it's fast." "Sometimes, more than 100 miles an hour." "Don't worry, I'm not going to start talking about trains." "It's something else." "Something much smaller, but in its own way, just as powerful." "It's the common cold." "Mankind's most universal infectious disease." "'Although the cold is generally a bit of a nuisance, what it can trigger is an every day miracle." "'It's nothing less than our own personal, human hurricane." "'A sneeze.'" "'A sudden impulse, co-ordinating most of the muscles of our upper body in a split-second reflex.'" "By combining the major muscle groups of the body like this, a sneeze can generate huge, propulsive force." "Now, using clever imaging techniques, we can finally see the powerful air currents it creates." "The source of this hurricane is the compression of hundreds of muscles in the body." "That mass of muscle power ejects, well, the stuff that's ejected in a sneeze at 100 miles an hour, dispersing it into 40,000 separate droplets." "If it were just snot, that would be gruesome enough." "But each of those droplets contains a payload of bacteria and viruses." "And their sole purpose is to pass on the infection, which raises an important question - how far can a sneeze go?" "Two or three rows, maybe?" "Five or six?" "By positioning agar dishes to trap the bacteria, it's possible to find out how far they can travel." "We can now measure the infectious range of a sneeze." "Well, we got some specialist snot scientists to actually do it for us, and this is what they found." "Two or three metres, the biggest droplets are starting to fall." "But they're still small enough that they can be picked up again by an air current." "These droplets are just about visible." "They're around the width of a human hair." "But that's not the end of the sneeze because as the droplets travel, they become smaller and smaller." "The smaller particles travel much further." "Some might even remain airborne for the rest of your journey and these smaller particles begin to divide and split further until they're too small to be seen by the naked eye." "But they're still there, oh, yes." "In tests, agar dishes placed 10 metres from a sneeze were infected." "They showed that the average sneeze contains millions of micro-organisms." "So in a crowded carriage, how many people here are within striking distance of getting splashed with these micro-organisms?" "The sneeze can easily travel 20 metres, or with a bit of assistance from air currents, 40 metres." "Yeah, we're all going to get it and those particles can survive from several hours to several days." "This is genuine bacteria growth from a hand print left for just two days." "So there you have it." "The sneeze." "Quite simply one of the world's most efficient methods of transmitting disease." "Good job it's usually just spreading the common cold." "The hidden power of this invisible world is not just on Earth." "Beyond the Earth, far above us, are invisible forces that can affect the entire planet." "The sun." "It's essential to life on Earth." "From a distance, provider of warmth and light." "Up close, a violent furnace, erupting with solar storms." "Storms that can cause havoc here on Earth, with the potential to wipe out every single electrical and telecommunications system worldwide." "We've known for some time that solar storms are linked to the intense magnetic activity of the sun, but we've never been able to see them close up, to understand how and why." "Now, this gang of terribly clever scientists are hoping to launch the world's most powerful solar telescope." "And they're doing it to get a glimpse of something that's normally invisible... ..a tiny patch of the sun that's 93 million miles away." "The gondola that we're going to lift up with this balloon is taking us to a new frontier in science - looking at the fine structures on the solar surface." "Up to now, it is, in a sense, invisible to our instruments." "They've waited years for this moment." "Now, launch conditions are perfect." "The balloon is filled with pressurised helium." "85 million dollars of equipment and only one shot at the launch." "No pressure, then." "The angle of launch needs to be exactly right." "APPLAUSE" "Six acres of balloon successfully takes flight, rising at 1,000 ft per minute." "Sunrise, all right!" "I think he's pleased." "The balloon has to withstand temperatures as low as minus 90 as it travels through the Earth's outer atmosphere and into the edge of space." "The pointing system is very high precision pointing accuracy and it amounts to taking the telescope and pointing it at those trees, several hundred metres away and being able to focus on one pine needle." "It was thought that the sun's most intense areas of magnetism..." "..were in sunspots - these dark areas here." "But the telescope shows something unexpected." "The most intense magnetic activity isn't in the sun spots, but hidden in the crevices between the bubbling plasma of the sun." "These tiny, bright white specks have a higher magnetic field than any other place on the sun." "And it's only now that they've been able to see them." "By discovering these new magnetic fields, scientists are closer to understanding the destructive power of solar storms." "But if the smaller structures of the sun could change our entire world, here on earth, the microscopic has the same power." "But this power doesn't disrupt the planet, it supports it." "Yup, sometimes you really do have to brave the elements to enjoy the delights of the British coastline." "But have you ever stopped to think what's beside us, when we're beside the sea?" "Let's take a look." "Yeah, well, it looks to be pretty empty." "In fact, hidden in the sea is a vast, rich world, a dominant force of life on Earth, an essential for our planet and our own survival." "Plankton." "These tiny creatures, virtually invisible to us, are an entire universe of astonishing life forms." "And all life on the planet depends on them." "Plankton provide 50% of the oxygen we breathe." "And we're now realising that they may play an even more important role." "Throughout the ocean, fish are disappearing from our seas." "The cod and haddock we scoff with chips are plummeting." "Now, new techniques and cameras are allowing us to solve one part of the mystery." "To a tiny plankton, swimming through the sea is like wading through treacle." "As they swim, they leave a wake behind them..." "..like footprints in the snow." "Larger fish use these wakes to home in on their dinner." "But in some places, the seas appear to be getting warmer and a change of even one degree has an effect on these plankton." "The warmer water is thinner and the trails don't last as long." "That makes it harder for the fish to catch their prey." "And by looking into this microscopic world, we've discovered something else." "In the warmer water, a different type of plankton is thriving." "One which is faster, much faster." "These super fast plankton can move 500 body lengths a second, which is like us travelling at nearly 2,000 miles an hour." "Which is bad news for the fish that feed on them." "Fish like the cod and haddock that are plummeting." "Looking into the vital microscopic world has discovered one answer to the mystery and shown us how important it is never to lose sight of the smaller picture." "These organisms that live in the ocean might be invisible to the naked eye, but their existence is vital to the existence of life on this planet." "Imagine if we could see all these invisible micro-worlds, vivid and all around us." "The hidden power of a snowflake." "Nature's hidden designs." "Seeing the invisible renews our sense of wonder." "Subtitles by Red Bee Media Ltd" "E-mail subtitling@bbc.co.uk"