Physics of the Future: How Science Will Shape Human Destiny and Our Daily Lives by the Year 2100 (44 page)

Up to 30 percent of the electricity generated by an electrical plant can be wasted in the transmission. Room temperature superconducting wires could change all that, thereby saving significantly on electrical costs and pollution. This could also have a profound impact on global warming. Since the world’s production of carbon dioxide is tightly connected to energy use, and since most of that energy is wasted to overcome friction, the age of magnetism could permanently reduce energy consumption and carbon dioxide production.

Without any extra input of energy, room temperature superconductors could produce supermagnets capable of lifting trains and cars so they hover above the ground.

One simple demonstration of this power can be done in any lab. I’ve done it several times myself for BBC-TV and the Science Channel. It’s possible to order a small piece of ceramic high-temperature superconductor from a scientific supply company. It’s a tough, gray ceramic about an inch in size. Then you can buy some liquid nitrogen from a dairy supply company. You place the ceramic in a plastic dish and gently pour the liquid nitrogen over it. The nitrogen starts to boil furiously as it hits the ceramic. Wait until the nitrogen stops boiling, then place a tiny magnet on top of the ceramic. Magically, the magnet floats in midair. If you tap the magnet, it starts to spin by itself. In that tiny dish, you may be staring at the future of transportation around the world.

The reason the magnet floats is simple. Magnetic lines of force cannot penetrate a superconductor. This is the Meissner effect. (When a magnetic field is applied to a superconductor, a small electric current forms on the surface and cancels it, so the magnetic field is expelled from the superconductor.) When you place the magnet on top of the ceramic, its field lines bunch up since they cannot pass through the ceramic. This creates a “cushion” of magnetic field lines, which are all squeezed together, thereby pushing the magnet away from the ceramic, making it float.

Room temperature superconductors may also usher in an era of supermagnets. MRI machines, as we have seen, are extremely useful but require large magnetic fields. Room temperature superconductors will allow scientists to create enormous magnetic fields cheaply. This will allow the future miniaturization of MRI machines. Already, using nonuniform magnetic fields, MRI machines about a foot tall can be created. With room temperature superconductors, it might be possible to reduce them to the size of buttons.

In the movie
Back to the Future Part III,
Michael J. Fox was filmed riding a hoverboard, a skateboard that floated in air. After the movie debut, stores were flooded with calls from kids asking to purchase the hoverboard. Unfortunately, hoverboards do not exist, but they might become possible with room temperature superconductors.

One simple application of room temperature superconductors is to revolutionize transportation, introducing cars and trains that float above the ground and thus move without any friction.

Imagine riding in a car that uses room temperature superconductors. The roads would be made of superconductors instead of asphalt. The car would either contain a permanent magnet or generate a magnetic field via a superconductor of its own. The car would float. Even compressed air would be enough to get the car going. Once in motion, it would coast almost forever if the road were flat. An electric engine or jet of compressed air would be necessary only to overcome air friction, which would be the only drag that the car faces.

Even without room temperature superconductors, several nations have produced magnetic levitating trains (maglev) that hover above a set of rails containing magnets. Since the north poles of magnets repel other north poles, the magnets are arranged so that the bottom of the train contains magnets that allow them to float just above the tracks.

Room-temperature superconductors may one day give us flying cars and trains. These may float on rails or over superconducting pavement, without friction. (
photo credit 5.3
)

Germany, Japan, and China are leaders in this technology. Maglev trains have even set some world records. The first commercial maglev train was the low-speed shuttle train that ran between Birmingham International Airport and Birmingham International Railway Station in 1984. The highest recorded maglev speed was 361 miles per hour, recorded in Japan on the MLX01 train in 2003. (Jet airplanes can fly faster, partly because there is less air resistance at high altitudes. Since a maglev train floats in air, most of its energy loss is in the form of air friction. However, if a maglev train were operating in a vacuum chamber, it might travel as fast as 4,000 miles per hour.) Unfortunately, the economics of maglev trains has prevented them from proliferating around the world. Room temperature superconductors might change all that. This could also revitalize the rail system in the United States, reducing the emission of greenhouse gases from airplanes. It is estimated that 2 percent of greenhouse gases come from jet engines, so maglev trains would reduce that amount.

By the end of the century, another possibility opens up for energy production: energy from space. This is called space solar power (SSP) and involves sending hundreds of space satellites into orbit around the earth, absorbing radiation from the sun, and then beaming this energy down to earth in the form of microwave radiation. The satellites would be based 22,000 miles above the earth, where they become geostationary, revolving around the earth as fast as the earth spins. Because there is eight times more sunlight in space than on the surface of the earth, this presents a real possibility.

At present, the main stumbling block to SSP is cost, mainly that of launching these space collectors. There is nothing in the laws of physics to prevent collecting energy directly from the sun, but it is a huge engineering and economic problem. But by end of the century, new ways of reducing the cost of space travel may put these space satellites within reach, as we will see in
Chapter 6
.

The first serious proposal for space-based solar power was made in 1968, when Peter Glaser, president of the International Solar Energy Society, proposed sending up satellites the size of a modern city to beam power down to the earth. In 1979, NASA scientists took a hard look at his proposal and estimated that the cost would be several hundred billion dollars, which killed the project.

But because of constant improvements in space technology, NASA continued to fund small-scale studies of SSP from 1995 to 2003. Its proponents maintain that it is only a matter of time before the technology and economics of SSP make it a reality. “SSP offers a truly sustainable, global-scale and emission-free electricity source,” says Martin Hoffert, a physicist formerly at New York University.

There are formidable problems facing such an ambitious project, real and imaginary. Some people fear this project because the energy beamed down from space might accidentally hit a populated area, creating massive casualties. However, this fear is exaggerated. If one calculates the actual radiation hitting the earth from space, it is too small to cause any health hazard. So visions of a rogue space satellite sending death rays down to earth to fry entire cities is the stuff of a Hollywood nightmare.

Science fiction writer Ben Bova, writing in the
Washington Post
in 2009, laid out the daunting economics of a solar power satellite. He estimated that each satellite would generate 5 to 10 gigawatts of power, much more than a conventional coal-fired plant, and cost about eight to ten cents per kilowatt-hour, making it competitive. Each satellite would be huge, about a mile across, and cost about a billion dollars, roughly the cost of a nuclear plant.

To jump-start this technology, he asked the current administration to create a demonstration project, launching a satellite that could generate 10 to 100 megawatts. Hypothetically, it could be launched at the end of President Obama’s second term in office if plans are started now.

Echoing these comments was a major initiative announced by the Japanese government. In 2009, the Japanese Trade Ministry announced a plan to investigate the feasibility of a space power satellite system. Mitsubishi Electric and other Japanese companies will join a $10 billion program to perhaps launch a solar power station into space that will generate a billion watts of power. It will be huge, about 1.5 square miles in area, covered with solar cells.

“It sounds like a science fiction cartoon, but solar power generation in space may be a significant alternative energy source in the century ahead as fossil fuel disappears,” said Kensuke Kanekiyo of the Institute of Energy Economics, a government research organization.

Given the magnitude of this ambitious project, the Japanese government is cautious. A research group will first spend the next four years studying the scientific and economic feasibility of the project. If this group gives the green light, then the Japanese Trade Ministry and the Japanese Aerospace Exploration Agency plan to launch a small satellite in 2015 to test beaming down energy from outer space.

The major hurdle will probably not be scientific but economic. Hiroshi Yoshida of Excalibur KK, a space consulting company in Tokyo, warned, “These expenses need to be lowered to a hundredth of current estimates.” One problem is that these satellites have to be 22,000 miles in space, much farther than satellites in near-earth orbits of 300 miles, so losses in transmission could be huge.

But the main problem is the cost of booster rockets. This is the same bottleneck that has stymied plans to return to the moon and explore Mars.

Unless the cost of rocket launches goes down significantly, this plan will die a quiet death.

Optimistically, the Japanese plan could go operational by midcentury. However, given the problems with booster rockets, more likely the plan will have to wait to the end of the century, when new generations of rocket drive down the cost. If the main problem with solar satellites is cost, then the next question is: Can we reduce the cost of space travel so that one day we might reach the stars?

We have lingered long enough on the shores of the cosmic ocean. We are ready at last to set sail for the stars.
—CARL SAGAN

In powerful chariots, the gods of mythology roamed across the heavenly fields of Mount Olympus. On powerful Viking ships, the Norse gods sailed across the cosmic seas to Asgard.

Similarly, by 2100, humanity will be on the brink of a new era of space exploration: reaching for the stars. The stars at night, which seem so tantalizingly close yet so far, will be in sharp focus for rocket scientists by the end of the century.

But the road to building starships will be a rocky one. Humanity is like someone whose outstretched arms are reaching for the stars but whose feet are mired in the mud. On one hand, this century will see a new era for robotic space exploration as we send satellites to locate earthlike twins in space, explore the moons of Jupiter, and even take baby pictures of the big bang itself. However, the manned exploration of outer space, which has enthralled many generations of dreamers and visionaries, will be a source of some disappointment.