"Also, most writers have never been any farther off the surface of Earth than the few miles up that an intercontinental cruiser takes them. "And yet, the modern 'adventure' novel invariably takes place in space. "I can read Westerns because I neither know nor care what the Old American West was _really_ like. I can sit back and sink into the never-never land that the Western tells about and enjoy myself because I am not forced to compare it with reality. "But a 'space novel' written by an Earthside hugger is almost as much a never-never land, and I have to keep comparing it with what is actually going on around me. And it irritates me." "But, aren't some of them pretty well researched?" Hull asked. "Obviously, you haven't read many of them," Jayjay said. "Sure, some of them are well researched. Say one half of one per cent, to be liberal. The rest don't know what they're talking about!" "But--" "For instance," Jayjay continued heatedly, "you take a look at every blasted one of them that has anything to do with a spacecraft having trouble. They have to have an accident in space in order to disable the spaceship so that the hairy-chested hero can show what a great guy he is. So what does the writer do? He has the ship hit by a meteor! A meteor!" Hull thought that over for a second. "Well," he said tentatively, "a ship _could_ get hit by a meteor, couldn't it?" Jayjay closed his eyes in exasperation. "Of course it could! And an air-ship can run into a ruby-throated hummingbird, too. But how often does it happen? "Look: We're hitting it up at about one-fortieth of the velocity of light right now. What do you think would happen if we got hit by a meteor? We'd be gone before we knew what had happened. "Why doesn't it happen? Because we can spot any meteor big enough to hurt us long before it contacts us, and we can dodge it or blast it out of the way, depending on the size. "You've seen the outer hull of this ship. It's an inch thick shell of plastic, supported a hundred feet away from the steel hull by long booms. Anything small enough to get by the detectors will be small enough to burn itself out on that hull before it reaches the ship. The--" * * * * * Jayjay Kelvin was not ordinarily a man to make long speeches, especially when he knew he was telling someone something that they already knew. But this time, he was beating one of his favorite drums, and he went on with his tirade in a fine flush of fury. Alas ... poor Jayjay. Actually, Jayjay Kelvin can't be blamed for his attitude. All he was saying was that it was highly improbable that a spaceship would be hit by a meteor. In one way, he was perfectly right, and, in another, he was dead wrong. How small must a piece of matter be before it is no longer a meteor?