From space, astronauts can see people making love as a tiny speck of light. Not light, exactly, but a glow that could be mistaken for light--a coital radiance that takes generations to pour like honey through the darkness to the astronaut's eyes. In about one and a half centuries--after the lovers who made the glow will have long been laid permanently on their backs--metropolises will be seen from space. They will glow all year. Smaller cities will also be seen, but with great difficulty. Shtetls will be virtually impossible to spot. Individual couples, invisible. The glow is born from the sum of thousands of loves: newlyweds and teenagers who spark like lighters out of butane, pairs of men who burn fast and bright, pairs of women who illuminate for hours with soft multiple glows, orgies like rock and flint toys sold at festivals, couples trying unsuccessfully to have children who burn their frustrated image on the continent like the bloom a bright light leaves on the eye after you turn away from it. Some nights, some places are a little brighter. It's difficult to stare at New York City on Valentine's Day, or Dublin on St. Patrick's. The old walled city of Jerusalem lights up like a candle on each of Chanukah's eight nights... , the glow...will say in one and a half centuries. .