Emergence of Special Relativity from Causal Sets


Causal Set Theory (CST) is one of the current serious attempts at creating a discrete model of the fine level structure of spacetime. It relies on a small number of basic assumptions. It is accessible to non-experts. The plausibility of some of the effects of special relativity can be seen quite simply without any mathematics. In this post I am going to show in diagrams how this happens. You won’t need any technical knowledge here, you won’t need to know anything about special relativity, and you won’t have to look at a single equation. (For those interested, I’ll quarantine some equations and technical details in sections in a coloured font, but there is no need to look at these if you don’t want to.)

Currently there is a lot of early stage theoretical investigation going on in CST. Some of it is looking into special relativity. This post will show the sort of ideas that are being thrown around. In particular I’ll be trying to show intuitively how time dilation, length contraction and increase in mass are quite natural in CST.

It is precisely the discrete nature of CST that allows this more intuitive understanding of special relativity. Keeping track of a finite number of points is much simpler than keeping track of an infinite number of them. Basically, CST lends itself to visual explanation much better.

So without any nasty infinities to bother us, let’s go…
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