Many of us know the fairytale story of the perpetual motion machine. It’s a machine that can continue to work forever without an energy source. You set the machine into motion just once and it’ll continue to do work eternally without any added energy on your part. Something like this would become a source of free and endless power, completely revolutionizing our world in its mystical process. But it’s “mystical” for a reason. A perpetual motion machine would violate our laws of physics, specifically those of thermodynamics which describe the behavior of energy in our universe. For that reason scientists consider them a definite impossibility.
However, there is one technology we’ve already created which comes increasingly close to a perpetual motion machine. It’s powerful and mysterious, encouraging a frenzy in the scientific community as we come to know more about it over the decades. It holds within it the power to create a second industrial revolution. And autumn of this year we made a critical discovery in its field.
This is the story of the superconductor.
There is a reason why power plants are often erected so close to busy cities. Up to 30% of the electricity they generate can be lost in the transmission lines. This is a common problem with electrical appliances. Much of the energy is lost to heat. That is also why much of the space of a computer, for example, is devoted to cooling parts which help combat the heat generated from the circuits. Making advancements in the field of superconductors would enable us to make computers 1,000 times more powerful than the one you have in your home today. These next generation computers would be more compact, and internal superconducting connections would mean much faster processing.
Simply put, superconductors solve the problem of energy lost to heat. These special materials can carry electricity without losing any of that energy. This is an astounding feature. It sounds as fantastical as that image of a perpetual motion machine ambling along without any energy input. Impossible. And yet consider this: scientists were able to maintain an electrical current inside a superconducting ring for over 2 years. And this without the original energy source. In fact the only reason the current stopped is because the scientists lost access to their liquid helium, not because the current couldn’t have continued running. Our experiments lead us to believe that currents within superconducting materials could last hundreds of thousands of years, if not more. The electrical current in superconductors can flow forever, transmitting energy without any cost to us.
But the devil is in the details. The reason the liquid helium was so important is because it helped cool the superconducting materials to extremely low temperatures. Most superconductors work only at hundreds of degrees below the freezing point of water, near what we call absolute zero.
Absolute zero is the coldest possible temperature. It’s represented as 0 Kelvin (-273.15° Celsius or -459.67° Fahrenheit). The movement of atoms at this temperature is almost nothing. This is the key to superconductors. Normally, electrons moving through a wire will collide with other vibrating atoms, thus causing energy loss and resistance. But because the atoms are almost entirely non-moving at such frigid temperatures, electrons can pass by without collisions and without energy loss. Different materials will need to be lowered to different temperatures — known as their critical temperature — before they become superconducting. Interestingly enough, materials like gold, silver, and copper cannot be made into superconductors even though they are some of the best room-temperature conductors.
With the 80’s came the discovery of a new class of superconductors. These were made, oddly enough, from ceramics, and could be produced at much higher temperatures than former materials. Where other materials had to be just a few degrees above 0 Kelvin, the ceramics became superconducting at 92 Kelvin. They were so easy to make that anyone with $50 and a microwave could recreate them at home. This is strange. Ceramics are usually poor conductors. To this day, physicists aren’t entirely sure why these special ceramics become superconducting at all.
The ultimate dream is to be able to make this technology at room temperature. One of the highest recorded temperatures for superconductors is 138 Kelvin (-211° F or -135° C). Still nowhere near the average room at 70° F (21° C).
What would a world with room temperature superconductors look like? Besides more powerful and compact computers we’d also see a revolution in the transportation industry. Already the fastest trains on Earth — SCMaglev trains which can reach speeds of 375 mph — rely on superconducting magnets. Motors for ships and cars would be 1/10th the size they are now, and expensive MRI machines for medical diagnosis could fit in the palm of your hand. Superconductors can make more efficient electromagnets like the ones already found all over our house, hospitals, construction sites, and in our generators today.
But perhaps the most exciting prospect of superconductors is in regards to energy. Power plants wouldn’t have to be built close to cities since so much energy would no longer be lost during transmission. This is safer for people and reduces pollution, not to mention that superconducting wires would save us billions of dollars. And what if powerful superconducting magnets could help start atomic fusion reactions? Well, that would mean an almost endless supply of cheap energy for the world. Using superconducting materials to achieve fusion is known as the high-field pathway. Already high-field fusion devices are giving incredible results: research shows they would produce more energy than they consume.
In October of this year we came a step closer to realizing room temperature superconductors. Scientists created a material with no electrical resistance operating at 59° F (15° C). This material was made of hydrogen, carbon, and sulfur. The only downside is that the compound only maintained superconductivity at incredible pressures similar to those at the center of our planet. The goal now is to find a material that will be superconducting both at room temperatures and at normal atmospheric pressures.
We know superconductors have potential. Though they seem something so nascent and sensational, they are not condemned to the world of fairytales. The question is not if they can exist, but rather when they will become practical and affordable for our society.
In the words of physicist Michio Kaku, a technology like superconductors would usher in a new era. If up until now we have been living in the age of electricity then room-temperature superconductors would bring with them the age of magnetism. A time marked by a resplendent abundance of energy for all — a time marked by better transportation between far reaches of the world. If only the ride towards that technology were as fast and as smooth as the levitating trains it’s inspired. We innovate now, at night, by the light of the electric bulb. Working towards a future that’s magnetic.