“What if they have a close-in weapons system like our ships?” I ask. “Won’t matter a bit,” Dr. Stewart says. “It would take terajoules of energy to break that freighter apart and boil all that water away. And even if they blew it up right now, all the debris would still hit them at the same speed. Physics,” she adds with a slight smile. “Nobody’s immune to physics. I don’t care how big and tough they are.”

