There was a collective gasp, faces turned up like flowers.
Bisesa shielded her eyes. And there in the sky, among the swarming crowd of planes and helicopters, a glimmering thread descended from space.
51: A Signal from Earth
In this system of a triple star, the world orbited far from the central fire. Rocky islands protruded from a glistening icescape, black dots in an ocean of white. And on one of those islands lay a network of wires and antennae, glimmering with frost. It was a listening post.
A radio pulse washed across the island, much attenuated by distance, like a ripple spreading across a pond. The listening post stirred, motivated by automatic responses; the signal was recorded, broken down, analyzed.
The signal had structure, a nested hierarchy of indices, pointers, and links. But one section of the data was different. Like the computer viruses from which it was remotely descended, it had self-organizing capabilities. The data sorted themselves out, activated programs, analyzed the environment they found themselves in—and gradually became aware.
Aware, yes. There was a personality in these star-crossing data. No: three distinct personalities.
“So we’re conscious again,” said the first, stating the obvious.
“Whoopee! What a ride!” said the second, skittishly.
“There’s somebody watching us,” said the third.
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Afterword
The idea of using space-based mirrors to modify Earth’s climate goes back to the visionary German-Hungarian thinker Hermann Oberth. In his book The Road to Space Travel (1929), Oberth suggested using huge orbiting mirrors to reflect sunlight to the Earth, to prevent frosts, control winds, and to make the polar regions habitable. In 1966 the U.S. Department of Defense studied the idea for rather different purposes, as a way to light up the Vietnamese jungles at night.
Not surprisingly Oberth’s idea appealed to the Russians, much of whose territory is at high latitudes—and who had a deep and ancient fascination with the sun (chapter 42). They actually tested a space mirror in 1993, when a twenty-meter disk of aluminized plastic was unfolded in Earth orbit. Cosmonauts aboard the Mir space station saw a spot of reflected light pass over the surface of Earth, and observers in Canada and Europe reportedly saw a flash of light as the beam passed over them.
Meanwhile in the 1970s the German-born American space engineer Krafft Ehricke made an intensive study of the uses of what he called “space light technology” (see Acta Astronautica 6, page 1515, 1979). In the context of mitigating global warming, the idea of using space mirrors to deflect light from an overheating Earth was revived by American energy analysts as recently as 2002 (see Science 298, page 981).
But much more ambitious uses of space light technology have been explored. Space light is by far the most abundant energy flow in the solar system—and it is free, for whatever purpose we choose. We could stave off the next Ice Age, we could shield Venus to make it habitable, we could warm up Mars—and for how to sail on space light, see “The Wind from the Sun” (available in Clarke’s collected stories, Gollancz, 2000).
Aurora (chapter 9) is actually the name of an ambitious new program of space exploration put together by the European Space Agency. The program is similar in broad outlines to the new direction in human space exploration for NASA announced by President Bush in January 2004. If the programs go ahead as planned, it seems likely that they will develop cooperatively—and that the timetable we indicate in this book, with a manned landing on Mars in the 2030s, might indeed come about.
The idea of the mass driver, an electromagnetic launcher on the Moon (chapter 19), was originated by Clarke in a paper published in the Journal of the British Interplanetary Society (November 1950).
British engineers have a proud tradition of devising plausible spaceplane designs (chapter 23); see for example a recent article on Skylon by Richard Varvill and Alan Bond in the Journal of the British Interplanetary Society (January 2004).
The development of new materials appears to be bringing the notion of a “space elevator” (chapter 50) closer to reality (see Clarke’s Fountains of Paradise, 1979). See The Space Elevator by Bradley Edwards, BC Edwards, 2002.
And there really will be a total solar eclipse over the western Pacific on April 20, 2042. See NASA’s Goddard Space Flight Center Eclipse Home Page for precise predictions.
We’re very grateful to Professor Yoji Kondo (aka Eric Kotani) for his generous advice on some technical aspects.
Sir Arthur C. Clarke
Stephen Baxterra
November 2004
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