Invisibility – fact or fantasy?
Today on Radio New Zealand National after the 11am news I’ll talk about the science of invisibilty, and whether it could ever be made real.
Read on for my notes, or after about 11:30 you can download the audio as ogg or mp3.
Clip 1: Invisible Man by Queen (first 10 seconds)
Q: you mean for real, or just being invisible on the Internet?
A: You aren’t invisible on the Internet. Well, if you are an expert who has done everything conceivable, you just might be, but I wouldn’t rely on it. The rest of us – not a chance.
No, I’m talking about real life invisibility.
Q: Science fiction?
A: Sounds that way, doesn’t it? And, frankly, it still is. But some quite rapid progress is getting made. There are two basic ways you can go about invisibility – the obvious and reasonably simple one is to cover the object you want invisible with LCD screens that show the scene behind the object. People are playing with that now.
But there is a much fancier approach using what are called “metamaterials”. These are materials that are constructed to bend light around them. They are still at an early research stage, but they could hold the key to real invisibility.
Q: How does that work?
A: Light is a wave, which is partly why we can reflect and refract it. It doesn’t always travel in straight lines. But to really manipulate light, you have to be able to construct materials which have a surface pattern on the same scale as the wavelength of light. Visible light has a wavelength of about 500 nanometres. That’s two million waves per metre. Our materials science isn’t really good enough to make reasonably sized objects with regular surface detail at that scale. But that’s likely to improve.
Radar waves – remember, light is just a kind of radio wave, and radar works using radio waves of a longer wavelength – they would be easier deflect around an object. There’s a lot of research going on around that, and I’d be surprised if a lot of it hadn’t already been implemented.
Q: You mean in “stealth” aircraft?
A: Yes, exactly. They are stealthy because they can avoid radar detection, but they’re not invisible to the naked eye. Maybe in the next few years it will become possible.
Play out to “As Close as This” – The Muttonbirds
Links
The godfather of invisibility explains – a great blog entry by journalist Peter Nowak, and how to make an invisibility cloak.