“But look how much the shelter is stopping,” John said, checking the dosimeter pinned to his shirt. “I’m still at only point three rem!”

That was several lifetimes of dentists’ X-rays, to be sure, but the radiation outside the storm shelter was already 70 rem, well on its way to a lethal dose, so they were getting off lightly. Still, the amount flying through the rest of the ship! Billions of particles were penetrating the ship and colliding with the atoms of water and metal they were huddled behind; hundreds of millions were flying between these atoms and then through the atoms of their bodies, touching nothing, as if they were no more than ghosts. Still, thousands were striking atoms of flesh and bone. Most of those collisions were harmless— but in all those thousands, there were in all probability one or two (or three?) in which a chromosome strand was taking a hit, and kinking in the wrong way: and there it was. Tumor initiation, begun with just that typo in the book of the self. And years later, unless the victim’s DNA luckily repaired itself, the tumor promotion that was a more or less unavoidable part of living would have its effect, and there would appear a bloom of Something Else inside: cancer. Leukemia, most likely; and, most likely, death.

So it was hard not to regard the figures unhappily. 1.4658 rem, 1.7861, 1.9004. “Like an odometer,” Boone said calmly as he looked at his dosimeter. He was gripping a rail with both hands and pulling himself back and forth, as if doing isometric exercises. Frank saw it and said, “John, what the hell are you doing?”

“Dodging,” John said. He smiled at Frank’s frown. “You know— moving target!”

People laughed at him. With the extent of the danger precisely charted on screens and graphs, they were beginning to feel less helpless. This was illogical, but naming was the power that made every human a scientist of sorts. And these were scientists by profession, with many astronauts among them as well, trained to accept the possibility of such a storm. All those mental habits began channeling their thoughts, and the shock of the event receded a bit. They were coming to terms with it.