Physics of the Future_ How Science Will Shape Human Destiny... Part 15

It all boils down to this. Gravity is attractive and can compress gas evenly into a sphere. Stars can form effortlessly. But electromagnetism is both attractive and repulsive, so gases bulge out in complex ways when compressed, making controlled fusion exceedingly difficult. This is the fundamental problem that has dogged physicists for fifty years.

(photo credit 5.1)

Until now. Physicists now claim that the ITER has finally worked out the kinks in the stability problem with magnetic confinement.

The ITER is one of the largest international scientific projects ever attempted. The heart of the machine consists of a doughnut-shaped metal chamber. Altogether, it will weigh 23,000 tons, far surpa.s.sing the weight of the Eiffel Tower, which weighs only 7,300 tons.

Two types of fusion. On the left, lasers compress a pellet of hydrogen-rich materials. On the right, magnetic fields compress a gas containing hydrogen. By midcentury, the world may derive its energy from fusion. (photo credit 5.2)

The components are so heavy that the roads transporting the equipment have to be specially modified. A large convoy of trucks will transport the components, with the heaviest weighing 900 tons and the tallest being four stories high. The ITER building will be nineteen stories tall and sit on a huge platform the size of sixty soccer fields. It is projected to cost 10 billion euros, a cost shared by seven member states (the European Union, the United States, China, India, j.a.pan, Korea, and Russia).

When it is finally fired up, it will heat hydrogen gas to 270 million degrees Fahrenheit, far surpa.s.sing the 27 million degrees Fahrenheit found in the center of the sun. If all goes well, it will generate 500 megawatts of energy, which is ten times the amount of energy originally going into the reactor. (The current record for fusion power is 16 megawatts, created by the European JET (Joint European Torus) reactor at the Culham Science Center, in Oxfords.h.i.+re, UK.) After some delays, the target date for break-even is now set to be 2019.

The ITER is still just a science project. It is not designed to produce commercial power. But physicists already are laying the groundwork for the next step, taking fusion power to the marketplace. Farrokh Najmabadi, who leads a working group looking into commercial designs for fusion plants, has proposed ARIES-AT, a smaller machine than the ITER, which would produce a billion watts at roughly 5 cents per kilowatt-hour, making it compet.i.tive with fossil fuels. But even Najmabadi, who is optimistic about fusion, admits that fusion won't be ready for widespread commercialization until the middle of the century.

Another commercial design is the DEMO fusion reactor. While the ITER is designed to produce 500 megawatts for a minimum of 500 seconds, the DEMO will be designed to produce energy continually. The DEMO adds one extra step lacking in the ITER. When fusion takes place, an extra neutron is formed, which quickly escapes from the chamber. However, it is possible to surround the chamber with a special coating, called the blanket, specifically designed to absorb the energy of this neutron. The blanket then heats up. Pipes inside the blanket carry water, which then boils. This steam is sent against the blades of a turbine that generates electricity.

If all goes well, the DEMO will go online in 2033. It will be 15 percent larger than the ITER reactor. DEMO will produce twenty-five times more energy than it consumes. Altogether, DEMO is expected to produce 2 billion watts of power, making it comparable to a conventional power plant. If the DEMO plant is successful, it could lead to rapid commercialization of this technology.

But many uncertainties remain. The ITER reactor has already secured the funding necessary for construction. But since the DEMO reactor is still in its planning stages, delays are to be expected.

Fusion scientists believe that they have finally turned the corner. After decades of overstatements and failures, they believe that fusion is within grasp. Not one but two designs (NIF and ITER) may eventually bring fusion electricity into the living room. But since neither NIF nor ITER is yet delivering commercial fusion power, there is still room for the unexpected, such as tabletop fusion and bubble fusion.

TABLETOP FUSION.

Because the stakes are so high, it is also important to acknowledge the possibility of solving the problem from an entirely different, unexpected direction. Because fusion is such a well-defined process, several proposals have been made that are outside the usual mainstream of large-scale funding but that still have some merit. In particular, some of them might one day achieve fusion on a tabletop.

In the final scene in the movie Back to the Future, Back to the Future, Doc Brown, the crazy scientist, is seen scrambling to get fuel for his DeLorean time machine. Instead of fueling up with gasoline, he searches garbage cans for banana peels and trash and then dumps everything into a small canister called Mr. Fusion. Doc Brown, the crazy scientist, is seen scrambling to get fuel for his DeLorean time machine. Instead of fueling up with gasoline, he searches garbage cans for banana peels and trash and then dumps everything into a small canister called Mr. Fusion.

Given a hundred years, is it possible that some breakout design may reduce huge football fieldsize machines to the size of a coffeemaker, like in the movie?

One serious possibility for tabletop fusion is called sonoluminescence, which uses the sudden collapses of bubbles to unleash blistering temperatures. It is sometimes called sonic fusion or bubble fusion. This curious effect has been known for decades, going back to 1934, when scientists at the University of Cologne were experimenting with ultrasound and photographic film, hoping to speed up the development process. They noticed tiny dots in the film, caused by flashes of light generated by the ultrasound creating bubbles in the fluid. Later, the n.a.z.is noticed that bubbles emitted from their propeller blades often glowed, indicating that high temperatures were somehow being produced inside the bubbles.

Later, it was shown that these bubbles were glowing brightly because they collapsed evenly, thereby compressing the air in the bubble to enormously high temperatures. Hot fusion, as we saw earlier, is plagued by the uneven compression of hydrogen, either because laser beams striking the pellet of fuel are misaligned or the gas is being squeezed unevenly. As a bubble shrinks, the motion of the molecules is so rapid that air pressure inside the bubble quickly becomes uniform along the bubble walls. In principle, if one can collapse a bubble under such perfect conditions, one might attain fusion.

Sonoluminescence experiments have successfully produced temperatures of tens of thousands of degrees. Using n.o.ble gases, one can increase the intensity of light emitted from these bubbles. But there is some controversy over whether it can achieve temperatures hot enough to produce nuclear fusion. The controversy stems from the work of Rusi Taleyarkhan, formerly of the Oak Ridge National Laboratory, who claimed in 2002 that he was able to achieve fusion with his sonic fusion device. He claimed to have detected neutrons from his experiment, a sure sign that nuclear fusion was taking place. However, after years of work by other researchers who have failed to reproduce his work, this result, for the moment, has been discredited.

Yet another wild card is the fusion machine of Philo Farnsworth, the unsung coinventor of TV. As a child, Farnsworth originally got the idea for TV by thinking of the way a farmer plows his fields, row after row. He even sketched the details of his prototype at the age of fourteen. He was the first to transfer this idea to a fully electronic device capable of capturing moving images on a screen. Unfortunately, he was unable to capitalize on his landmark invention and was mired in lengthy, messy patent fights with RCA. His legal battles even drove him crazy, and he voluntarily checked himself into an insane asylum. His pioneering work on TV went largely unnoticed.

Later in life, he turned his attention to the fusor, a small tabletop device that can actually generate neutrons via fusion. It consists of two large spheres, one inside the other, each made of a wire mesh. The outer mesh is positively charged, while the inner mesh is negatively charged, so protons injected through this mesh are repelled by the outer mesh and attracted to the inner mesh. The protons then smash into a hydrogen-rich pellet in the middle, creating fusion and a burst of neutrons.

The design is so simple that even high school students have done what Richter, Pons, and Fleischmann could not do: successfully generate neutrons. However, it is unlikely that this device will ever yield usable energy. The number of protons that are accelerated is extremely small, and hence the energy resulting from this device is very tiny.

In fact, it is also possible to produce fusion on a tabletop using a standard atom smasher or particle accelerator. An atom smasher is more complicated than a fusor, but it can also be used to accelerate protons so that they can slam into a hydrogen-rich target and create fusion. But again, the number of protons that are fused is so small that this is an impractical device. So both the fusor and atom smasher can attain fusion, but they are simply too inefficient and their beams are too thin to produce usable power.

Given the enormous stakes, no doubt other enterprising scientists and engineers will have their chance to turn their bas.e.m.e.nt contraptions into the next mega invention.

AGE OF MAGNETISM.

The previous century was the age of electricity. Because electrons are so easily manipulated, this has opened up entirely new technologies, making possible radio, TV, computers, lasers, MRI scans, etc. But sometime in this century, it is likely that physicists will find their holy grail: room temperature superconductors. This will usher in an entirely new era, the age of magnetism.

Imagine riding in a magnetic car, hovering above the ground and traveling at several hundred miles per hour, using almost no fuel. Imagine trains and even people traveling in the air, floating on magnetism.

We forget that most of the gasoline we use in our cars goes to overcoming friction. In principle, it takes almost no energy to ride from San Francisco to New York City. The main reason this trip consumes hundreds of dollars of gasoline is because you have to overcome the friction of the wheels on the road and the friction of the air. But if you could somehow cover the road from San Francisco to New York with a layer of ice, you could simply coast most of the way almost for free. Likewise, our s.p.a.ce probes can soar beyond Pluto with only a few quarts of fuel because they coast through the vacuum of s.p.a.ce. In the same way, a magnetic car would float above the ground; you simply blow on the car, and the car begins to move.

The key to this technology is superconductors. It has been known since 1911 that mercury, when cooled to four degrees (Kelvin) above absolute zero, loses all electrical resistance. This means that superconducting wires have no energy loss whatsoever, since they lack any resistance. (This is because electrons moving through a wire lose energy as they collide with atoms. But at near absolute zero, these atoms are almost at rest, so the electrons can easily slip through them without losing energy.) These superconductors have strange but marvelous properties, but one severe disadvantage is that you have to cool them to near absolute zero with liquid hydrogen, which is very expensive.

Therefore, physicists were in shock in 1986 when it was announced that a new cla.s.s of superconductors had been found that did not need to be cooled to these fantastically low temperatures. Unlike previous materials like mercury or lead, these superconductors were ceramics, previously thought to be unlikely candidates for superconductors, and became superconductors at 92 degrees (Kelvin) above absolute zero. Embarra.s.singly, they became superconductors at a temperature that was thought to be theoretically impossible.

So far, the world record for these new ceramic superconductors is 138 degrees (Kelvin) above absolute zero (or -211 F). This is significant, since liquid nitrogen (which costs as little as milk) forms at 77 K (-321 F) and hence can be used to cool these ceramics. This fact alone has drastically cut the costs of superconductors. So these high-temperature superconductors have immediate practical applications.

But these ceramic superconductors have just whetted the appet.i.te of physicists. They are a giant step in the right direction, but still they are not enough. First, although liquid nitrogen is relatively cheap, you still have to have some refrigeration equipment to cool the nitrogen. Second, these ceramics are difficult to mold into wires. Third, physicists are still bewildered by the nature of these ceramics. After several decades, physicists are not quite sure how they work. The quantum theory of these ceramics is too complicated to solve at the present time, so no one knows why they become superconductors. Physicists are clueless. There is a n.o.bel Prize waiting for the enterprising individual who can explain these high-temperature superconductors.

But every physicist knows the tremendous impact that a room temperature superconductor would have. It could set off another industrial revolution. Room temperature superconductors would not require any refrigeration equipment, so they could create permanent magnetic fields of enormous power.

For example, if electricity is flowing inside a copper loop, its energy dissipates within a fraction of a second because of the resistance of the wire. However, experiments have shown that electricity within a superconducting loop can remain constant for years at a time. The experimental evidence points to a lifetime of 100,000 years for currents inside a superconducting coil. Some theories maintain that the maximum limit for such an electrical current in a superconductor is the lifetime of the known universe itself.

At the very least, such superconductors could reduce the waste found in high-voltage electrical cables, thereby reducing the cost of electricity. One of the reasons an electrical plant has to be so close to a city is because of losses in the transmission lines. That is why nuclear power plants are so close to cities, which poses a health hazard, and why wind power plants cannot be placed in areas with the maximum wind.

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.

THE MAGNETIC CAR AND TRAIN.

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 pa.s.s through the ceramic. This creates a "cus.h.i.+on" of magnetic field lines, which are all squeezed together, thereby pus.h.i.+ng 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 b.u.t.tons.

In the movie Back to the Future Part III, 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. 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.

MAGLEV TRAINS AND CARS.

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, j.a.pan, 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 j.a.pan on the MLX01 train in 2003. (Jet airplanes can fly faster, partly because there is less air resistance at high alt.i.tudes. 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.

ENERGY FROM THE SKY.

By the end of the century, another possibility opens up for energy production: energy from s.p.a.ce. This is called s.p.a.ce solar power (SSP) and involves sending hundreds of s.p.a.ce 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 s.p.a.ce 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 s.p.a.ce 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 s.p.a.ce travel may put these s.p.a.ce satellites within reach, as we will see in Chapter 6 Chapter 6.

The first serious proposal for s.p.a.ce-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 s.p.a.ce 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 s.p.a.ce might accidentally hit a populated area, creating ma.s.sive casualties. However, this fear is exaggerated. If one calculates the actual radiation hitting the earth from s.p.a.ce, it is too small to cause any health hazard. So visions of a rogue s.p.a.ce 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 Was.h.i.+ngton Post Was.h.i.+ngton 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 compet.i.tive. Each satellite would be huge, about a mile across, and cost about a billion dollars, roughly the cost of a nuclear plant. 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 compet.i.tive. 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 j.a.panese government. In 2009, the j.a.panese Trade Ministry announced a plan to investigate the feasibility of a s.p.a.ce power satellite system. Mitsubis.h.i.+ Electric and other j.a.panese companies will join a $10 billion program to perhaps launch a solar power station into s.p.a.ce 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 s.p.a.ce may be a significant alternative energy source in the century ahead as fossil fuel disappears," said Kensuke Kanekiyo of the Inst.i.tute of Energy Economics, a government research organization.

Given the magnitude of this ambitious project, the j.a.panese 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 j.a.panese Trade Ministry and the j.a.panese Aeros.p.a.ce Exploration Agency plan to launch a small satellite in 2015 to test beaming down energy from outer s.p.a.ce.

The major hurdle will probably not be scientific but economic. Hiros.h.i.+ Yos.h.i.+da of Excalibur KK, a s.p.a.ce 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 s.p.a.ce, 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 j.a.panese 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 s.p.a.ce travel so that one day we might reach the stars?

We have lingered long enough on the sh.o.r.es of the cosmic ocean. We are ready at last to set sail for the stars.

-CARL SAGAN

In powerful chariots, the G.o.ds of mythology roamed across the heavenly fields of Mount Olympus. On powerful Viking s.h.i.+ps, the Norse G.o.ds sailed across the cosmic seas to Asgard.

Similarly, by 2100, humanity will be on the brink of a new era of s.p.a.ce 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 stars.h.i.+ps 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 s.p.a.ce exploration as we send satellites to locate earthlike twins in s.p.a.ce, explore the moons of Jupiter, and even take baby pictures of the big bang itself. However, the manned exploration of outer s.p.a.ce, which has enthralled many generations of dreamers and visionaries, will be a source of some disappointment.

EXTRASOLAR PLANETS.

One of the most stunning achievements of the s.p.a.ce program has been the robotic exploration of outer s.p.a.ce, which has vastly expanded the horizon of humanity.

Foremost among these robotic missions will be the search for earthlike planets in s.p.a.ce that can harbor life, which is the holy grail of s.p.a.ce science. So far, ground-based telescopes have identified about 500 planets...o...b..ting in distant star systems, and new planets are being discovered at the rate of one planet every one to two weeks. The big disappointment, however, is that our instruments can identify only gigantic, Jupiter-sized planets that cannot sustain life as we know it.

To find planets, astronomers look for tiny wobbles in the path of a star. These alien solar systems can be likened to a spinning dumbbell, where the two b.a.l.l.s revolve around each other; one end represents the star, clearly visible by telescope, while the other represents a Jupiter-sized planet, which is about a billion times dimmer. As the sun and Jupiter-sized planet spin around the center of the dumbbell, telescopes can clearly see the star wobbling. This method has successfully identified hundreds of gas giants in s.p.a.ce, but it is too crude to detect the presence of tiny, earthlike planets.

The smallest planet found by these ground-based telescopes was identified in 2010 and is 3 to 4 times as ma.s.sive as earth. Remarkably, this "superearth" is the first one to be in the habital zone of its sun-i.e., at the right distance to have liquid water.

All this changed with the launch of the Kepler Mission telescope in 2009 and the COROT satellite in 2006. These s.p.a.ce probes look for tiny fluctuations in starlight, caused when a small planet moves in front of its star, blocking its light by a minuscule amount. By carefully scanning thousands of stars to look for these tiny fluctuations, the s.p.a.ce probes will be able to detect perhaps hundreds of earthlike planets. Once identified, these planets can be quickly a.n.a.lyzed to see if they contain liquid water, perhaps the most precious commodity in s.p.a.ce. Liquid water is the universal solvent, the mixing bowl where the first DNA probably got off the ground. If liquid-water oceans are found on these planets, it could alter our understanding of life in the universe.

Journalists in search of a scandal say, "Follow the money," but astronomers searching for life in s.p.a.ce say, "Follow the water."

The Kepler satellite, in turn, will be replaced by other, more sensitive satellites, such as the Terrestrial Planet Finder. Although the launch date for the Terrestrial Planet Finder has been postponed several times, it remains the best candidate to further the goals of Kepler.

The Terrestrial Planet Finder will use much better optics to find earthlike twins in s.p.a.ce. First, it will have a mirror four times larger and one hundred times more sensitive than that of the Hubble s.p.a.ce Telescope. Second, it will have infrared sensors that can nullify the intense radiation from a star by a factor of a million times, thereby revealing the presence of the dim planet that may be orbiting it. (It does this by taking two waves of radiation from the star and then carefully combining them so that they cancel each other out, thereby removing the unwanted presence of the star.) So in the near future, we should have an encyclopedia of several thousand planets, of which perhaps a few hundred will be very similar to the earth in size and composition. This, in turn, will generate more interest in one day sending a probe to these distant planets. There will be an intense effort to see if these earthlike twins have liquid-water oceans and if there are any radio emissions from intelligent life-forms.