Superconductivity has always sounded like a ridiculous pipe dream, or perhaps a weird plot device from one of the stranger episodes of Doctor Who. But as a huge story from the Institute of Physics points out, we already live in a world where superconductivity is used pretty often. And soon it seems it will hit the mainstream, and possibly affect your life.
But before we get to the juicy bits, you need to ask the following question: What exactly is superconductivity?
A superconductor can actually be described in one deceptively simple-looking phrase: Superconductors can allow electrical current to flow through them forever, with no external power source needed. That's basically the inverse of every single electrical thing you've ever touched or seen in your life. From the cables in the overhead electrical grid to the microscopically tiny gold strands that connect the silicon in your computer's chips to the black metal and plastic box you think of as a chip, every electrical wire has a certain resistance. Simply put this means though they can let electrons flow through them to create electrical current, they're not too fond of the fact...they "resist" it. To get over the resistance and to push the electrons through the wire, you have to apply a force—which may be a new way for you to think of applying "voltage."
Superconductors have zero resistance—they love having current flowing through them. The how and the why of this involves some freaky and difficult physics, and varies between materials. We're still working it out. But the upshot of zero resistance is that when you squirt some electrical current into a superconducting wire, it'll happily just rush around forever with no voltage "push" required.
Why's this useful? For starters it's much less wasteful in terms of energy. Every single electrical wire that has normal resistance wastes some of the electrical energy pushing through it—this is true for both your computer circuitry (ever wondered why your laptop gets hot?) and overhead grid wires. In an era where we worry about climate damage, this is a bad thing. It's also a bad thing for your lap when you're gaming on your portable PC. Superconducting wires can, in many cases, lead to very very little energy being wasted when you're moving some current from point A to point B.
Superconductors can also create some very weird and wonderful effects, like incredibly powerful electromagnets. It's helium-cooled superconducting loops inside an MRI machine that let the device make all those amazing scans inside the human body, with particular success in scanning the brain. Similar magnets make the Large Hadron Collider in Geneva work its magic, pushing back the boundaries of science (and ultimately leading to breakthroughs that will touch your life. Remember where the computer came from). But the size and complexity of an MRI machine, to say nothing of the LHC, are all notable.
This is what breakthroughs in superconductor design will change.
A more portable superconducting magnet can, for example, very precisely and swiftly separate out many impurities in water, leading to potable water in situations where it may be difficult to find. A superconductor magnetic sensor could very accurately and safely detect the presence of unexploded ordnance, or land mines, in a post-conflict area with greater safety than rival systems. Superconducting magnets in levitating trains could allow for swifter, safer, and much more energy-efficient mass transportation—there are even some prototypes out there that prove this. Superconducting mains electrical wires leading from power stations mean that more of the power they generate will get to the end user without being wasted as heat.
And superconducting technology supercomputers could perform mind-bogglingly swift calculations, using incredibly tricky algorithms that could help us design better technology or at least better understand climate change without contributing to the problem themselves.
In fact brand new research into a weird class of superconductor suggests that we could make reliable, or "fault-tolerant" quantum computers using a strange material called a topological insulator. Quantum computers are technologically a bit fragile, and the quantum bits that they process are easily messed up by resistance in a regular conductor. That's not the case in a superconductor. And the potential for quantum computing to change the world is very well known, even if the details are only now being fleshed out. Thus the quantum computer may prove to be the place where superconductors really have the biggest impact.
Is all this going to happen tomorrow? Not necessarily. Superconductors that work at normal, everyday temperatures aren't really here yet. But we've advanced our understanding and ability to work with the technology to the point where superconductors going to become much more common. Next time you see the word in a headline, which may be soon, you'll know more about it.
[Image: Flickr user Matt Buck]