When I say forward, I'm thinking of forward in terms of 3D space, not forward in terms of time. Thinking about time doesn't bring clarity. As you point out, yo

When I say forward, I'm thinking of forward in terms of 3D space, not forward in terms of time. Thinking about time doesn't bring clarity. As you point out, you could lay out a timeline such that forward in space means forward in time (text adventure game). Or you could lay out a timeline such that forward in space means backward in time (macOS Time Machine). The 100k Stars zoom has no notion of time, just of space. When thinking about space, up generally corresponds to forward. Think of a signpost with an arrow pointing right, that means go right. If a signpost has an arrow pointing up, that means go forward. Or any map, e.g. a physical map, or gps navigation software, or a videogame minimap: in those up means forward. Our maps are meant to be read from above. If we lay a map on a table, we look down at it, and forward means forward. If we then pick up the map, so that our face faces forward instead of down, now up means forward. If we had a map meant to be read from below, and we stuck the map on an upside-down table hovering over our heads and bent our necks backward to read it, then if forward means forward on that map, when we take the map off the hovering table and stop bending our necks back, up would mean backward. That's not how we make maps though.