But it is possible to detect minute deviations in this signal, and these fluctuations - seen as mottling in the map - are understood to reflect the differences in the density of matter when the light parted company and set out on its journey all those years ago.
Is it possible, in the crazy there-one-minute-gone-the-next lifestyle that expats live, to meet someone while staring at a map on a street corner that is everything you never knew you needed?