Invisibility Cloak and Carbon Nanotubes

around itself, making it invisible to microwaves. The lime-green waves are microwaves. When an ordinary copper ring is placed in their path, the waves are disturbed. But when the metamaterial is placed there, the waves bend around it and seamlessly merge on the other side as if there was nothing there. To the invisibility cloak is something that's entirely new. It's a structure that doesn't exist in nature, something that couldn't be fashioned out of existing materials, and something that really functions in an almost science fictiony way that you might imagine wouldn't have been possible just a few years ago. We've demonstrated the principle of invisibility at microwave frequencies. The microwave frequencies are a few centimeters in size or at least maybe the size of your thumb. So now we're looking into the future and whether or not we can do this invisible light. In addition to microwaves, scientists have already succeeded in bending red and blue light. Full invisibility may be just decades away. The first applications are likely to be for military stealth, but as hard to imagine, we'll stop there. The ancients have always been fascinated by the property of invisibility. Over 2,000 years ago, Plato refers to this story. Once there was a poor shepherd who finds a cave and inside the cave there's a ring, a ring of invisibility. And he uses that ring to sneak into the king's castle, seduce the queen, plot against the king. He killed the king and became the next monarch. While Plato used that story to show that invisibility is so powerful, it could cause societies to disintegrate. Well, I'm not sure about that, but I'm sure about one thing and that is our mastery over the properties of matter. We'll massively open up our horizons. In the past, new materials often had a profound impact on our society. Concrete and steel, first mass produced in the 19th century, reshaped our cities in the lives of all city dwellers. The Brooklyn Bridge was the largest steel suspension bridge ever built. It's massive weight held up by 3,600 miles of hefty steel cable. When it opened in 1883, it allowed a commuters into Manhattan and changed the city forever. But I believe the impact of steel will be nothing compared with the new materials will be creating in the future. In the 21st century, science is experimenting with new classes of materials like carbon resheds, ceramics and polymers, and one of the most promising is a substance that's actually stronger and lighter than steel. And in fact, you could replace the steel in these cables with fibers as thin as a human hair. That's the promise of carbon nanotubes. Carbon nanotubes are a miracle of nature. They're made out of individual carbon atoms arranged in a hollow cylinder. The cylinder surface is just one atom across. The diameter is only 50 atoms across and these tubes can be billions of atoms long. These extraordinary dimensions give carbon nanotubes their unique properties. Their atoms are bonded with the strength of diamonds yet they have the flexibility of fiber. Hi, I'm Stephen Steiner. Steve, how do you do? Right. Right. Here at MIT, Stephen Steiner and John Hard are going to show me how to grow my own. So this is where it all happens, right? Yes, these are our furnaces where we grow nanotubes. So tell me, where does the carbon come from? Come from a gas, which is right in this tank here. So it's actually sort of an age-old process. We take a carbon containing gas and you put your chip on which we want to grow nanotubes and we heat up the furnace and the heat causes the gas to decompose and by that reaction, by that chemical reaction, we can grow billions of nanotubes. My dangerous is it? No, no, we just want to make sure we don't get the samples dirty because the process needs to be pretty clean because we're growing such small things. Our substrate has catalyst seeds, nanoparticles of a metal and these will act as seeds from which the nanotubes will grow. So we're going to start preheating them for the growth process. It's hard to believe that under this tiny piece of glass, we're creating one of the strongest materials known to man. Yet carbon nanotubes are so small, we can only see them under a powerful microscope. This is a block of nanotubes and that's the human hair. So now we can focus in and there we have a strand of carbon nanotubes which is sitting on the human hair. We can zoom in and compare the size of the hair to the size of the nanotubes because even this strand contains hundreds, thousands of nanotubes all together. It really puts it into perspective how small the nanoscale really is. So far we can only grow short lengths of carbon nanotubes. But hundreds of businesses and researchers are racing to develop longer carbon nanotubes in order to harness their huge potential. In the future, we might be able to use carbon nanotubes for unsmashable cars, uncollapsible buildings, ultra light jet planes and some people even believe we could use them to build a highway into space. This is the famous Seattle Space Needle built in 1962 for the world's fair at the dawn of the space age when people dreamed about visiting Mars and Venus. Well that never happened. 50 years later the space program seems to be stuck. Space travel is simply too expensive. We need a way to go into outer space without explaining all that expensive rocket fuel. Well one thing out of science fiction is the space elevator but it was considered just a far-fetched curiosity until recently. With the amazing strength and lightness of carbon nanotubes, it's now a serious proposition. Space elevators are a very clever idea and there's no reason why they shouldn't work. I mean the idea that you just essentially lower a carbon nanotube broke down onto the surface and which things up is it sounds like science fiction but in my opinion anything that's scientifically possible and not ruled out by the laws of physics should be possible in engineering terms at some point in the future. The space elevator was the brainchild of a visionary Russian scientist, Constantine Ciel Koski, who has inspired way back in 1895 by the newly built Eiffel Tower. Since the 1970s NASA has been funding a trickle of research into what is essentially a permanent lift into space. A space elevator is nothing but a super strong cable of the 60,000 miles in length. Suspended from outer space and anchored on the planet Earth. What keeps it afloat is the spin of the Earth. Think of a ball on a string as you twirl a ball on a string it doesn't fall down because at the centrifugal force of being spun in a circle. Now you can calculate that steel is not strong enough to resist the centrifugal force but for the first time in history we have a substance carbon nanotubes with more than enough strength to resist the pressure of being suspended from outer space. And that's why NASA is offering a half million dollar prize to the first group that can build the simple prototype of a space elevator. Just outside Cielo, one of the most promising teams is using laser power to drive a robot climber up a cable. Yeah you know I'm dressed I don't think we have quite enough hands in here yet can you uh yeah we're making a telling the team call laser mode.