Thursday, May 27, 2010

Foundations 1: Special Relativity - Greg Egan

"Anyone who reads science fiction will be familiar with some of the remarkable predictions of twentieth-century physics. Time dilation, black holes, and the uncertainty principle have all been part of the SF lexicon for decades. In this series of articles I'm going to describe in detail how these phenomena arise, and along the way I hope to shed some light on the theories that underpin them: special relativity, general relativity, and quantum mechanics. The foundations of modern physics.

These articles are meant for the interested lay reader. If you can follow high school algebra and geometry, and aren't afraid to take in a few new concepts — which is the whole point, after all — nothing here should faze you.


The idea that we inhabit a four-dimensional spacetime is a very natural and intuitive one. It's only because we take the duration of objects so much for granted that we tend to gloss over it and refer to them as three-dimensional. Since most of the Earth's landscape changes slowly, factoring out time from our mental models and paper maps is a very pragmatic thing to do, but it's this unchanging space that we imagine for convenience that's the abstract mental construct, not spacetime. Spacetime is simply what we live in, all four dimensions of it."

5 out of 5

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