"I'd heard that hypothesis, about the passage of time." It's nice when puzzle pieces come together. "Reinforcements for it are encouraging. We can focus on what we have to do now."

And not worry about...okay, he's still going to worry occasionally, because "worry" is his default setting. But it's - reassuring, to think his adventures won't cause his parents any more fear for him. They've been so supportive. Ken tries to repay that by keeping them in the loop.

And Senku will be able to see his world revitalize itself. Senku will be able to go to space.

Ken never forgets a person's dream.