He left the room and returned quickly with a sheaf of papers.
"They call 'em space-resonant," he said with a wry chuckle, "but I call 'em symbiotic."
"Meaning?"
"Why, it seems as though we have a closed system of radioactivity here," he said.
"But the space-resonant elements are only faintly radioactive," objected Virginia.
"According to outside detectors," he said. "But this is an internally closed system. There are two basic elements and two isotopes of each, all operating in a closed system."
"How?"
He handed her a sheet of paper containing nuclear equations.
① 121A227 + 0n1 —--> 121A280
② 121A280 - 1e0 —--> 122B280