There were excuses on both sides; there always are. Earth was tired; it had spent itself, sending out its best blood to the stars. It saw power slipping from its hands, and knew that it had already lost the future. Why should it speed the process by giving to its rivals the tools they needed ?

The Federation, on the other hand, looked back with a kind of affectionate contempt upon the world from which it had sprung. It had lured to Mars, Venus and the satellites of the giant planets some of the finest intellects and the most adventurous spirits of the human race. Here was the new frontier, one that would expand forever toward the stars. It was the greatest physical challenge mankind had ever faced, it could be met only by supreme scientific skill and unyielding determination. These were virtues no longer essential on Earth; the fact that Earth was well aware of it did nothing to ease the situation.

All this might lead to discord and interplanetary invective, but it could never lead to violence. Some other factor was needed to produce that, some final spark which would set off an explosion echoing round the solar system.

That spark had now been struck. The world did not know it yet, and Sadler himself had been equally ignorant a short six months ago. Central Intelligence, the shadowy organization of which he was now a reluctant member, had been working night and day to neutralize the damage. A mathematical thesis entitled “A Quantitative Theory of the Formation of the Lunar Surface Features” did not look like the sort of thing that could start a war—but an equally theoretical paper by a certain Albert Einstein had once ended one.