Ah, I think I understand! Something 18bnly away from us today has a light bubble that includes objects outside our light cone. If you can get there in 45y, tha

Ah, I think I understand! Something 18bnly away from us today has a light bubble that includes objects outside our light cone. If you can get there in 45y, that doesn’t mean 45y has passed at that location. In fact if it’s 18bnly away, that means you’d arrive in 18bn years from their perspective. And not 18bn years from what you saw when you left, but 18bn years from when they saw you leave. By that time, space will have expanded enough that it’s no longer possible to see past.