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Sunday, 11 March 2012

What Are Superconductors?

How will Physics change our world in the next 100 years? Today at The Aftermatter, we're looking at how superconductors will revolutionise our power supplies, and the impacts this will have.

Physics, considered by many to be a boring, inane, number-crunching field, seems to be the least likely place to find magic. But the magic of today is the physics of the future: in the next 100 years it will alter so definitively our society that, if we were to visit it today, we would consider it impossible. Yes, past dreams such as flying cars and robot housekeepers have not fully materialised, but imagine someone from 1912 visiting today’s society. They would see strange machines that display movies without a projector. They would see machines that could display almost any book ever published within 30 seconds. They would see telegraphs without wires that could understand you, and answer your requests. People would hand over money using cards made out of a material that hadn’t even been discovered yet. To the visitor from 1912, the present would be magic. It would be impossible. 2112 will be no different. Science fiction will be come science fact, not just confined to a geeky sector of the super-rich, but for everyone. Physics, more than politics, will change the course of the world over the next century, and we are blessed to be able to witness the start of it.

One technology about which a lot of research is already being done is superconductivity. A superconductor is a material that has no resistance to electrical current. Resistance is the friction of the electrical world. In this way, copper wire is analogous to road travel on Earth: the road and the air provide friction that opposes your motion. However, if you provided the same force in space, where there are no air particles or road to create friction, then you would continue moving until something stopped you: theoretically, you would never slow down! In this way, using a superconductor is like travelling into space. Current and resistance are linked in the following equation:

V=IR
Where V is voltage, I is current, and R is resistance. 
This means that in superconductors, where R is 0, with any voltage at all, the current (the rate at which electrons move through the material) is theoretically infinite, and thus the electricity can keep travelling without slowing down. 

The only problem with this is that at the moment, superconductors have to be extremely cold to work. The first superconductor that was discovered, Mercury, only works at 4° Kelvin, or about -269°C. Scientists have made a bit more progress since then on warmer superconductors. In 1986, scientists found that certain ceramics could also superconduct, and this time at much higher temperatures, such as 92°K (-182°C), and the current world record for the highest temperature superconductor is 132°K(-135°C), which is still far too cold for most purposes, but, crucially, it is warm enough to be cooled by liquid nitrogen, which is as cheap as milk. More recently, in 2010, a team of researchers lead by Yoshihiko Takano, during a rather boozy party in the laboratory, found that certainalcoholic drinks increase the superconductive temperatures of certain ceramics. Bizarrely, the alcohol itself seems to be nothing to do with the results: a mixture of water and ethanol had no effect on the ceramics. Experiments are still ongoing as to why these drinks have such an effect. Some have concluded that red wine improves the efficiency of both superconductors and academic researchers!

 Considering all this, within the next 60-100 years, it is likely that room temperature superconductors will be a reality. The consequences of this would be huge. Room-temperature superconductors allow for use in everyday life. Because superconductors are so efficient, electricity would become incredibly cheap. Currently, 30% of electricity is wasted in transmission between the power plant and the home, but superconductors would reduce this number to zero. This isn’t even considering the wastage that built in to our appliances in the form of copper wires. It would almost completely solve the energy crisis. But there is one thing that superconductors are exceptionally good at: electromagnetism. Strong electromagnets require huge amounts of electricity, but with superconductors this will become a very manageable and affordable amount to use.

In the same way that over the last century, electrical wires were proliferated into our society so that every wall contains them, once superconductors exist, electromagnets will be put into every floor, every wall and every road. If you then put electromagnets into, say, pieces of furniture, then your days of lifting sofas are over: you simply turn on the electromagnets and the sofa will hover into the air! You could then use a control pad to manipulate the sofa as you like, and then gradually turn off the magnets to lower it down gently. Some may think that this would have unwanted side effects, such as cutlery flying across the room as you’re moving the armchair, but, using magnetic shielding materials already in existence such as mu-metal, you can carefully direct the magnetic force to affect only the object you want. It would be a real-life manifestation of Harry Potter’s Wingardium Leviosa, what is magic today will be common place by the 2100’s.

Another use of these electromagnets will be in transport. As well as virtually eradicating resistance, electrical friction, superconductors will go a long way towards reducing physical friction in transport. By placing electromagnets on train tracks and in the train itself, it is possible to make the train hover just above the line, and then move without touching the actual track, meaning that there is no friction between the train and the track, and thus it can move much faster. This already exists: it is called MagLev, and is used as part of Japan and China’s rail systems. The trains in Shanghai run at over 268mph regularly, which is faster than any Formula 1 car, and in a test run reached a top speed of 311mph. The only thing stopping it spreading further is the cost of powering these powerful magnets, which would be reduced to almost zero with the dawn of room-temperature superconductors. There is no reason we would have to restrict ourselves to trains, either. If we placed electromagnets in the road and in cars, then our dream of the hover car would be complete. We would no longer need petrol, only electricity, which would be cheaper and more efficient than ever before. We will finally fulfill the predictions of countless science fiction writers: these wouldn’t just be wacky, gimmicky flying cars, these would actually have a purpose: they would be more efficient, and they would be everywhere. Great physics is sometimes spoilt by economics, but this is one case where they would walk hand in hand.

This is just one way in which Physics will change our future. Physicists make dreams realities; they make impacts that will last longer than that of any government. So much of our society today is shaped by technology; the Internet a prime example: it hasn’t just solved a problem, it has sculpted the world and society in a profound way. Technology will continue to do that, and it is Physics that provides it. Physics is ‘magic,’ physicists will be the ones recreating Hogwarts, and it will be the physicists of today who shape the world of tomorrow. 

We hope you enjoyed this post. If you have anymore questions, you can follow us on twitter, @theaftermatter, email us at contactus@theaftermatter.com or search "The Aftermatter"on Facebook. We really like hearing your feedback or just talking about the posts or other physics and maths. We hope you enjoyed this post.

Theo Caplan.

Check out our last two posts:
Artificial Intelligence Composers: Can computers write music? - How are computers managing to use algorithms to create music that sounds like it was written by a regular human?
What is the Theory of Everything? (Part 1) - How can a theory describe everything? And are there moral implications if it can?

What are we posting about next:
What is the Theory of Everything? (Part 2): String Theory - The first look into a theory that could possibly become a theory of everything. 

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