text: "There's a theory," McCall intoned as he checked the cameras a third time. "A line of reasoning, I should say, that time travel to the past is impossible. Otherwise, we would be inundated with tourists from the future." He continued with a small chuckle. Blakely nodded. "Plenty of logical arguments against. Creating paradoxes is too easy. Some even believe that any universe in which the conditions make time travel possible ceases to exist because of paradox." The monitor's glow reflected off his glasses, and he glanced at the steady green bar indicating the power levels were holding. "So the conditions in our universe, therefore, must make it impossible." "By all accounts, this shouldn't work at all, but the maths check out." McCall moved carefully back beyond the line of safety tape. "When activated, the field --" "Yes, I know." Blakely's forehead furrowed. "Focus on the task at hand." "You see," McCall blundered on, unabated, "the multiverse of possible timelines... A tree with near infinite branches." He held his hands up, fingers splayed. "The sphere will pass down one branch, into our past, and create a new branch where it simply emerges into existence at that point in time. It will cease to exist on this branch of the tree, and will exist on that one. Will have always existed as that branch stretches--" "Three seconds before you hit the switch, the iron sphere will appear on the charged plate in the sealed chamber." Blakely muttered. "'Effect prior to cause,' so you keep saying. Every time we run this experiment." McCall scowled, "For the record! For the *cameras*, not for you. I know *you* know all this." *For the Nobel committee, you mean*, Blakely thought, but did not say. A loud, metallic thud emitted from the white, pill-shaped vessel on the table. "Did we lose the vacuum seal again?" McCall stepped gingerly over cables snaking on the floor, and navigated his way around the camera tripod. He bent down over the table to inspect the pressure valve. Blakely stared at the display, his mouth slightly open. Within the sealed vacuum chamber across the lab, at the focal point of dozens of instruments and cameras, a one-kilogram sphere of iron had appeared. He sat back, slowly, then started.