From Geoff Harding, Sydney, Australia
The concept of quantised space-time may be the key to understanding the multiverse – and the requirement that the plethora of universes must display a wide range of properties that fortuitously result in a limited number being relatively stable and life-friendly (28 October, p 30).
If the fundamental constituents of space-time were to consist of a mixture of “pixels”, one could imagine that each universe had different proportions determined at its birth, with consequent variation of properties. The fundamental particles may thus be common to all, but they may interact differently due to the nature of the background space-time in which they exist.
