“Never understood how these work without energy,” says Mario quietly, one hand on the Time Tube.

“It puts you in quantastasis,” says Rasmussen.

Mario nods.

“And then we, ah, wait.”

“Until what?”

“Until it opens, for a forward jump. Backwards–until we train replacements, retire and die, Earth falls into the Sun, the universe goes into blueshift and collapses, explodes again–and this is the tricky quantum bit, so you and the Tube spontaneously reassemble the same way–Earth boils out, life appears, civilization. The Tube opens. You step out.”

Mario stares.

“We have better methods now,” says Rasmussen, slightly embarrassed.