Contact - Carl Sagan [121]
In the daylight, though, it's hard to see any sign of human habitation. But at night, except for the polar aurora, everything you see is due to humans, humming and blinking all over the planet. That swath of light is eastern North America, continuous from Boston to Washington, a megalopolis in fact if not in name. Over there is the burn off of natural gas in Libya. The dazzling lights of the Japanese shrimp fishing fleet have moved toward the South China Sea. On every orbit, the Earth tells you new stories. You can see a volcanic eruption in Kamchatka, a Saharan sandstorm approaching Brazil, unseasonably frigid weather in New Zealand. You get to thinking of the Earth as an organism, a living thing. You get to worry about it, care for it, wish it well. National boundaries are as invisible as meridians of longitude, or the Tropics of Cancer and Capricorn. The boundaries are arbitrary. The planet is real. Spaceflight, therefore, is subversive. If they are fortunate enough to find themselves in Earth orbit, most people, after a little meditation, have similar thoughts. The nations that had instituted spaceflight had done so largely for nationalistic reasons; it was a small irony that almost everyone who entered space received a startling glimpse of a transnational perspective, of the Earth as one world.
It wasn't hard to imagine a time when the predominant loyalty would be to this blue world, or even to the cluster of worlds huddling around the nearby yellow dwarf star on which humans, once unaware that every star is a sun, had bestowed the definite article: the Sun. It was only now, when many people were entering space for long periods and had been afforded a little time for reflection, that the power of the planetary perspective began to be felt. A significant number of these occupants of low Earth orbit, it turned out, were influential down there on Earth.
They had-from the beginning, from before humans ever entered space-sent animals up there. Amoebas, fruit flies, rats, dogs, and apes had become hardy space veterans. As spaceflights of longer and longer duration became possible, something unexpected was found. It had no effect on microorganisms and little effect on fruit flies. But for mammals, it seemed, zero gravity extended the lifespan. By 10 or 20 percent. If you lived in zero g, your body would spend less energy fighting the force of gravity, your cells would oxidize more slowly, and you would live longer. There were some physicians who claimed that the effects would be much more pronounced on humans than on rats. There was the faintest aroma of immortality in the air.
The rate of new cancers was down 80 percent for the orbital animals compared with a control group on the Earth. Leukemia and lymphatic carcinomas were down 90 percent. There was even some evidence, perhaps not yet statistically significant, that the spontaneous remission rate for neoplastic diseases was much greater in zero gravity. The German chemist Otto Warburg had, half a century before, proposed that oxidation was the cause of many cancers. The lower cellular oxygen consumption in the weightless condition suddenly seemed very attractive. People who in earlier decades would have made a pilgrimage to Mexico for laetrile now clamored for a ticket into space. But the price was exorbitant. Whether preventive or clinical medicine, spaceflight was for the few.
Suddenly, hitherto unheard of sums of money became available for investment in civilian orbital stations. By the very end of the Second Millennium there were rudimentary retirement hotels a few hundred kilometers up. Aside from the expense, there was a serious disadvantage, of course: Progressive osteological and vascular damage would make it impossible for you ever to come back to the gravitational field at the surface of the Earth. But for some of the wealthy elderly, this was no major impediment. In exchange for another decade of life, they were happy to retire to the sky and, eventually, to die there.
There were those