Produced by Greg Weeks, Stephen Blundell and the Online Distributed Proofreading Team at https://www.pgdp.net _The space ships were miracles of power and precision; the men who manned them, rich in endurance and courage. Every detail had been checked and double checked; every detail except--_ THE NOTHING EQUATION By TOM GODWIN [Illustration] The cruiser vanished back into hyperspace and he was alone in the observation bubble, ten thousand light-years beyond the galaxy's outermost sun. He looked out the windows at the gigantic sea of emptiness around him and wondered again what the danger had been that had so terrified the men before him. Of one thing he was already certain; he would find that nothing was waiting outside the bubble to kill him. The first bubble attendant had committed suicide and the second was a mindless maniac on the Earthbound cruiser but it must have been something inside the bubble that had caused it. Or else they had imagined it all. He went across the small room, his magnetized soles loud on the thin metal floor in the bubble's silence. He sat down in the single chair, his weight very slight in the feeble artificial gravity, and reviewed the known facts. The bubble was a project of Earth's Galactic Observation Bureau, positioned there to gather data from observations that could not be made from within the galaxy. Since metallic mass affected the hypersensitive instruments the bubble had been made as small and light as possible. It was for that reason that it could accommodate only one attendant. The Bureau had selected Horne as the bubble's first attendant and the cruiser left him there for his six months' period of duty. When it made its scheduled return with his replacement he was found dead from a tremendous overdose of sleeping pills. On the table was his daily-report log and his last entry, made three months before: _I haven't attended to the instruments for a long time because it hates us and doesn't want us here. It hates me the most of all and keeps trying to get into the bubble to kill me. I can hear it whenever I stop and listen and I know it won't be long. I'm afraid of it and I want to be asleep when it comes. But I'll have to make it soon because I have only twenty sleeping pills left and if--_ The sentence was never finished. According to the temperature recording instruments in the bubble his body ceased radiating heat that same night. * * * * * The bubble was cleaned, fumigated, and inspected inside and out. No sign of any inimical entity or force could be found.