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I originally composed this essay in Summer 1989 and I have updated it only slightly.
Of all the injuries that Humanity has inflicted upon Nature perhaps the greatest set is the harm we do as we fulfill our need for energy to drive our machines and our industrial chemistry, heat and cool our homes, and cook our food. The burning of coal and oil to generate electricity has created acidic rain and unbreathable air. The burning of gasoline for transportation does the same. In other parts of the world forests are stripped bare to provide firewood. In this part of the world the earth itself is stripped for coal. That our need for energy should induce us to accept such desperate measures is appalling enough, but the introduction into human society of robots and the Omnifex technology on the scale Iím assuming in these essays will only increase our need for energy, spectacularly so if we intend to lift all of Humanity out of poverty. Obviously we cannot reasonably hope to rely on our traditional sources of energy, even if they were not already on the verge of running out.
That conclusion is so obvious that some people began as far back as forty years ago (ca. 1950) trying to develop a source of energy that would be effectively inexhaustible and whose fuel could be acquired with little or no deleterious effect upon the natural environment. In the 1930's physicists theorized that the forcible fusion of hydrogen into heavier elements was the source of the starsí energy. A simple calculation indicates that the water in Earthís oceans contains enough deuterium, the more easily fusible heavy isotope of hydrogen, to provide each of ten billion people ten kilowatts of continuous power for slightly under five trillion years. In the 1950's physicists sought to exploit that power source by building in their laboratories a variety of machines that they hoped would function as thermonuclear reactors. Unfortunately the realities of high-temperature plasmas differ significantly from the physicistsí theories, so what was originally intended to be a straightforward development program became a back-to-the-drawing-board research program.
Work continues on the effort to harness nuclear fusion, but progress has been slow and shows few signs of speeding up. Laser-induced fusion, which was conceived to avoid the problems of high-temperature plasmas by using laser beams to implode pellets of frozen hydrogen, has proven to be more difficult than was originally assumed. And cold fusion using palladium electrodes in heavy water, a technique announced with great fanfare about a year ago (Iím typing this in February 1990), seems to generate more heat among physicists than it does in the glass reactors designed by Professors Stanley Pons and Martin Fleischmann [and itís still not going anywhere: 2014 Mar 02]. However, in spite of all those disappointments we do actually have a working thermonuclear reactor available to us for the tapping. Every second it whiffs four million tonnes of mass into energy and blows it into space as light. Itís a poorly shielded reactor, very sloppy with its high-energy radiation, but we seem to be stuck with it for the next five billion years, so we might as well make some use of it.
By the time raw sunlight reaches the top of Earthís atmosphere the inverse-square law of optics has diminished its power density to about one-and-a-third kilowatts per square meter. With current technology, mass-produced solar cells can convert about one quarter of that power into electricity, the remainder being converted, in compliance with the laws of thermodynamics, into waste heat. If we want to provide each of ten billion humans with ten continuous kilowatts of power, then we must set out 400,000 square kilometers of continuously illuminated collector surface. That corresponds to an array of solar cells that measures a little over 632 kilometers long (a little under four hundred miles) on each side.
Weíre certainly not going to build that installation on Earth. We would have to sacrifice at least 1,200,000 square kilometers of land area (the extra area being needed to compensate the effects of Earthís rotation) as well as build huge energy storage facilities. But itís not the technical difficulties implied by that number that will stop us: robots and Omnifices would handle them for us and, anyway, the site where we are going to build that installation presents even greater engineering challenges. No, what will stop us when we consider turning Earthís deserts into solar-power farms is the set of values that, more and more, will guide the evolution of civilization in the Twenty-First Century and beyond. Iíll grant that paving over Earthís deserts with solar-power collectors may not seem the stuff of tragedy, but I think thatís because we have forgotten how deserts touch the human soul. Itís no accident that the faiths of Judaism, Christianity, and Islam originated in the deserts of Sinai, Judea, and Arabia and were subsequently shaped by desert dwellers. That spiritual resource is founded on a profound sense of utter solitude that is simply incompatible with a major technological invasion. Thus, even the most forlorn empty lands (especially the most forlorn empty lands) of our deserts are best left to the sun, the wind, and seekers of dialogue with God.
The best location for solar-power plants is a circle 84,290 kilometers (52,260 miles) wide centered on Earth and lying more or less in Earthís equatorial plane. That would put the power plants 35,767 kilometers (22,175 miles) above the Equator, an altitude at which they must travel fast enough to revolve around Earth precisely once a day in order to remain in a circular orbit. Falling freely, weightlessly, in the vacuum of cislunar space, those vast, wide-flung arrays of solar panels can be given just enough rotation, about one degree per day, to keep them oriented permanently toward the sun with only minor maintenance required. Appearing to us to remain motionless in the sky above the Equator, they will float in continuous sunlight except for a few minutes to a little over an hour a day during an eighteen-day period at each of the vernal and autumnal equinoxes, when part of the power plantsí orbit passes through Earthís shadow.
Most of the material used to build those power plants will come from the moon (on a plan similar to that first proposed by Gerard OíNeill in the mid-1970's). Robots equipped with Omniphages will render the pulverized rock that comprises the moonís blanket of regolith into its constituent chemical elements and then use industrial Omnifices to form the desired elements into blocks suitable for shipping through space. The blocks will be heaved into space by an electromagnetic catapult, captured by a robot satellite hovering above the lunar farside, and then shipped aboard robotic rocketfreighters to the geosynchronous orbit (the 35,767-kilometer high orbit, so called because the revolution of an object in it is synchronized with Earthís rotation). There the blocks will be fed to Omniphages that feed the Omnifices from which the components of solar-power plants will emerge. Every now and then a rocketship from Earth will bring materials that canít be obtained from the moon.
Once the power plants are built and have been brought on line their thousands of square kilometers of solar panels, like immense leaves of glass, will carry out a strange inorganic photosynthesis. The panels will convert a portion of the sunlight falling upon them into electricity that will then flow through the plantís superconducting veins to huge klystrons. Basically electromagnetic whistles, the klystrons will convert the energy carried by the electricity into microwaves, which a phased-array antenna will shape into a narrow beam to be projected onto a receiving antenna on Earth. Covering a wide area inside an industrial park of robot factories, the rectifying antenna will absorb the microwaves, destroying them and converting the energy that they carry back into electricity. Manifested in the conventional sixty-cycle alternating current, that electricity will be fed into coaxial cables (which donít emit electromagnetic radiation) for distribution throughout our country.
Using power beamed from space to drive electricity through our wires will allow us to shut down and dismantle the coal- and oil-burning power plants that currently foul our air. It will allow us to shut down and dismantle the nuclear power plants that irritate so many people. Dams that have been built solely to provide hydroelectric power can also be taken down and their rivers allowed to run free again. In using space-collected solar power, then, we can take a large step toward healing the wounds that we have inflicted upon Nature.
However, that thought does raise one concern. The energy beamed to Earth will eventually be converted to heat. Since the energy is derived from sunlight that would not otherwise strike Earth, that heat will be an addition to the heat brought to Earth by direct sunlight. Might that additional heat raise Earthís temperature? Technically, the answer must be yes: any additional input of energy, however small, will raise Earthís temperature. The more significant question asks by how much the temperature will be raised. We have assumed that twenty-five percent of the sunlight falling onto our 400,000 square kilometers of solar panels will be converted into microwaves and beamed to Earth, so we will, in essence, be adding 100,000 square kilometers of heat-collecting area to the 128,000,000 square kilometers that Earth presents to the sun. A naive calculation based on the Stefan-Boltzmann law, which holds that radiant heat flux is proportional to the fourth power of the absolute temperature, indicates that our solar-power scheme will raise Earthís temperature by five one-hundredths of a centigrade degree. In order to raise Earthís temperature by one degree, according to that same naive calculation, we would have to expand our orbiting solar-power plants by 8,000,000 square kilometers, twenty times what we estimated we will need.
The above calculation is naive in the sense that it ignores the reality of Earth as a self-regulating mechanism and treats it as a purely passive blackbody radiator. But any additional heat brought to Earth activates mechanisms that make Earth cool down more efficiently. One obvious example is that of extra water evaporating from the warmer oceans and creating additional cloud cover, which then reflects more of the sunís light back into space before it can strike the ground and turn into heat. It seems clear, then, that we would have to generate quantities of power far exceeding the most unreasonable expectations before we would interfere with Nature through the extra heat we generate: activities requiring such quantities of power would most likely destroy the biosphere in other ways. We can be confident, then, that our rather modest plan to enrich the entire human race through the Omnifex technology will not precipitate an ecological disaster through its power source.
Beamed power will take care of the needs of stationary machinery, such as Omniphages and Omnifices. It will also be used indirectly by some robots. The robot waiter in a restaurant, for example, will have two sets of batteries, one being charged up while the other is being used. But beamed power would seem to be of little use to more mobile robots, such as our personal servants, or to other mobile machines, such as our cars.
Chemical energy, usually manifested in gasoline, is what we use to power our mobile machines today. Itís a dirty way to go, but it gets a lot of energy out of a small volume of fluid. As I recall, twenty gallons of gasoline was sufficient to keep my old 1972 Gremlin cranking out over one hundred horsepower for nearly half a day (and thatís at an estimated seventeen percent efficiency in the conversion of combustion heat into mechanical energy). A standard robot wonít be stronger than a horse, wonít generate more than one horsepower, and so should be able to run for several days on one gallon of gasoline.
Thatís not to imply that robots will contain small internal-combustion engines. I think we should not want to see millions of gasoline-powered robots putt-putt-putting around our cities. Actually our robots will draw their power from a device whose structure resembles that of an Omnifex. Two separate networks of capillaries will bring air and liquid fuel, such as gasoline or methanol, into the device. Molecules of fuel will be fed directly into their channels while molecular grabbers and stripper gates will take only oxygen molecules from the air and feed them into the oxidizer channels. Inside the device mechanisms similar to the stripper gates will tear the fuel molecules apart, rendering them into free atoms of carbon and hydrogen. Those atoms will then be fed to assemblers that will attach them to oxygen atoms held by other assemblers. Because the force attracting oxygen atoms to atoms of carbon and hydrogen is stronger than the force attracting atoms of carbon and hydrogen to each other, that process yields a net output of energy: thatís why hydrocarbons like gasoline generate heat when they burn in oxygen. But in a robotís metabolizer that process wonít be allowed to create more than a small amount of heat. Instead, the extra force generated by the creation of carbon dioxide and water will be made to drive atomic-scale mechanisms that generate direct-current electricity, which will then carry energy to the robotís muscles and computer brain.
Omnifex-derived metabolizers will be more efficient than conventional internal-combustion engines; that is, they will convert a higher percentage of the energy released by the conversion of fuel and oxygen into carbon dioxide and water into useful work. Further, because the chemical reactions are so tightly controlled, the metabolizers wonít create the oxides of nitrogen that necessarily accompany conventional combustion in Earthís nitrogen-rich atmosphere. Nor will they emit unburned or partially burned fuel (which we usually see as smoke coming from an automobileís exhaust pipe).
The metabolizers wonít emit the obvious forms of air pollution. They wonít create smog. But they will emit carbon dioxide and nowadays thatís considered something of a pollutant because when it is added to Earthís atmosphere it contributes to the atmosphereís ability to trap heat and thus raise Earthís temperature, a phenomenon better known as the greenhouse effect. However, the carbon dioxide coming out of our robots and other machines wonít be that kind of pollutant. Instead of being derived from carbon sources, such as coal and oil, that have been buried in the ground for millions of years and thus being essentially a new addition to the atmosphere, the carbon dioxide coming from our machines, like the carbon dioxide coming from our lungs, will be made of recycled carbon.
In every garage and carport there will be a small Omnifex that will create only one product, a hydrocarbon fuel (likely methanol rather than gasoline because methanol will burn cleaner in our automobile engines), and produce it at a rate sufficient to keep full the subterranean tank from which we fuel our machines. Most of the carbon used in that production will come from the atmosphere, drawn from the air by fast growing plants, such as water hyacinths, that are harvested by robots and thrown into industrial-scale Omniphages that then make the carbon available to our Omnifices.
In those ways and others our robotic and Omnifex technologies will be founded on a power base that is more benign, more friendly to Nature, than is the power base on which our current technology rests. It will enable us to pursue grand futuristic dreams while returning to the Nature-revering values of our Stone Age ancestors.
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