A good explanation as to what superconductivity is may be a proper place to start. We are all familiar with conductors; conductors allow a reasonably free flow of electricity through them. Copper is the major conductor used today because of its relatively low resistance to electric flow.
However, as good as copper may be, it does offer some resistance, and unfortunately that means over long distances a lot of electric power can be lost. In the United States we partially get around this issue by using alternating current (AC) rather than direct current (DC). The advantage of AC is that it allows for the use of an important electric component: a transformer.
Transformers utilize the magnetic field that is generated by AC to let voltage be "stepped up" and then later "stepped down." It so happens that if electricity is transmitted at higher voltages less power is lost during transmission. This is the reason that you see signs that say "Danger high voltage." Once the power reaches your house, had passed through a transformer that reduces it to the 120 V of household current. Since the current is AC this is really only an average current known as an RMS current.
Even with the higher voltage there is still a reasonable amount of loss of power over electric lines. What could possibly be done to alleviate this problem? Well, it turns out that there are materials that do not have this problem at all, and they are called superconductors.
Superconductors, unlike regular metals, conduct electricity without any resistance and thus no power loss whatsoever. That is right, absolutely zero power loss. The best thing about superconductors is that they are not some crazy theory that no one has been able to produce; they have actually been made in labs. So why in the world have we not switched all of our power lines to superconductors?
Well, the catch is that superconductors are typically only superconducting at extremely low temperatures, near absolute zero (a topic for another time -?suffice it to say absolute zero is the coldest temperature possible). These are not realistic temperatures to keep power lines at, even in the winter time.
What is exciting is that scientists have been able to make superconducting materials which superconduct at ever higher temperatures. Currently there are superconductors that work at temperatures as high as -217 F (and no that negative sign is not a mistake), which may not sound all that impressive but the original superconductors needed temperatures of around 452 degrees below zero.
One major roadblock to development of better superconductors has been a lack of understanding as to how something becomes superconducting; there are several theories, but none that seem to give a satisfactory explanation. Recently researchers may have made headway in getting at the root of this problem. They discovered that they could control the properties of a certain type of superconductor with flashes of light. The researchers were able to control when the material switched from an insulator (non-conductor) to metallic in nature (a conductor) using short pulses of light. So the use of light may shed light on the nature of superconductivity.
I almost left out another interesting property of superconductors. Since superconductors do such a wonderful job of conducting electricity, they also alter the magnetic fields around them. This means that superconductors can allow magnets to levitate, essentially for "free." Thus, superconductors could radically alter the way we travel. Think flying cars and an abundance of floating fast moving trains.
Here is to hoping that our superconducting future is right around the corner.