The room is small and bare, home to a cardboard cut-out of the Moon and a push-button game called Rocket Mission. Santi walks up to the game, hands in his pockets. “Wow. They really spared no expense.”

Thora joins him, still absorbed in her story. “I was thinking of climbing out of my window. To see what it’s like out there,” she says, as she punches in a launch sequence with the casual competence of the young.

“You probably shouldn’t,” says Santi, wondering whether he ever had dreams this vivid; certain that if he did, he never told his teachers about them. “Remember what we learned about gravity last week?”

Thora rolls her eyes as their imaginary craft reaches the mesosphere, solid rocket boosters falling back like spent candles. “I wouldn’t fall,” she says. “But I guess if I did, I’d find out if it was really somewhere else or not.”

A scientist at heart. Santi imagines Thora’s parents finding her flat on her back in the garden. Mr. López told me not to take anything for granted.

“So. What I wanted to ask was,” Thora says, “can windows take you to other places?”

He frowns. “I’m not sure I understand. I’m guessing you don’t mean places like your garden?”

“No,” she says firmly. “I mean like—other places.”

Santi watches the blip of their craft curve across the screen. “You mean other worlds?”

She lights up. “Yes. Other worlds.”

Santi smiles. The kind of conversation he’d imagined being a science teacher was all about. “Probably not. At least not on Earth. In space, there might be holes that could take you from one part of the universe to a different, faraway part.”

She frowns. “But my window couldn’t be one of those holes?”

“No. What you saw was probably just a trick of the light.” She looks so disappointed that he adds, “That doesn’t mean it’s boring! It’s very interesting, how what we see turns into what we think we see.”

“I know what I saw,” Thora insists.

The machine emits a strangled bleep. The screen flashes, prompting them for input.

“Look,” Santi says, glad for the distraction. “We have to decide whether to go through the debris field or reroute to avoid it.”

Thora, suddenly focused, stands on her tiptoes, squinting at the screen. “I suppose rerouting would be safer. But it says if we do that, it’ll take us longer to get there.”

Santi considers his words carefully. He knows what the right answer is, or at least the answer the machine wants. But he doesn’t want to teach Thora to be cautious, to always choose the safer path.

“We have shields,” he points out. “They might not catch everything, but they give us some protection. And going the long way would use up more fuel. But—you’re the captain. You should decide.”