When I think about infinity, I usually start with a straight line, or an open highway stretching off in the distance to a vanishing point. But to a pioneer, infinity is really about discovering new worlds. You can stop anywhere on that open highway — and there discover a new world. Or you can look into a telescope and see distant stars, each comprising whole new worlds. Or you can look in a microscope, and see bacteria and viruses — life at a whole unfamiliar scale. The more you look, the more you find. That’s what infinity is all about. The more rocks you uncover, the more you find underneath. Infinity is not a flimsy facade, nor a simple unbounded concept. That’s a long way from 1,2,3,…