> * ...but the idea that space is expanding implies an outer "edge" Space expension just means that the metric used to measure distance increases with time. It

> * ...but the idea that space is expanding implies an outer "edge" Space expension just means that the metric used to measure distance increases with time. It doesn't imply a border. Consider the function equivalent to the Euclidian distance on a line : d(x1,x2) = sqrt((x2-x1)^2) Now, you can consider the function : d2(x1,x2,y) = y * d(x1,x2) If you view x1 and x2 as positions on one axis and y as a position on the other one, you can think of d2 as the distance between x1 and x2 expanding as you go higher in the plane. Space expansion works in the same way but y is actually time.