## Egan again

Plus, Minus: A Gentle Introduction to the Physics of Orthogonal has a remarkably simple explanation of the speed of light limit, time dilation, and other effects of relativity. Using nothing more complicated than triangle geometry in a couple of different geometric systems.

As Egan works through some of the implications of a Riemannian universe that has no speed limit, he concludes "Life will need to master some delicate reactions" and "only certain structures will be stable". Of course, he needed to find a somewhat plausible way for life to work in order to write three novels about it (which are quite good reads).

He doesn't explicitly bring up the Anthrophic principle, but if life in a Riemannian universe would be very unlikely and fragile, it's a good thing this isn't one. Being limited by the speed of light seems like a reasonable tradeoff..

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I will have to check this out. Thanks for discussing it!

A colleague of mine, S. James Gates (theoretical physicist), uses something he calls "The Einstein Hypotenuse" to engage an audience with some skill in high school trigonometry in understanding how certain things, like the speed of light, are left invariant even as space and time change with relative motion. It sounds very similar to what Egan uses.