Explain

"Because they only respond to one thing: high-yield gamma radiation. The kind a warp core makes when it bursts," Thorne said. "If we land on Kepler with the engines running, they will follow us down. They will consume the colony. They will consume the planet. We are the infection, Commander. If we arrive, we doom the very world we swore to save."

"There wasn't time for a committee meeting, Commander. And there wasn't room for hope. Hope is a variable I cannot calculate." Thorne stood up and walked to the window, looking out at the vast, star-speckled blackness. "Now, go. Get to the cryo-bay. The blast shields will seal in ninety seconds." explain

Halloway narrowed his eyes. "What variables?" "Because they only respond to one thing: high-yield