A2.1 Appendix to Chapter 2: Going Deeper into Special Relativity
A optional deeper dive into special relativity. Worth getting into if it interests you but not needed to enable you to work through the rest of the chapters.
Having introduced the principles of special relativity in Chapter 2, we’ll explore its huge significance for our understanding of momentum and energy in Chapter 3. This, in turn, will lead us eventually to our starting point for getting into quantum theory.
If you’re interested in special relativity, however, there is much more to it that we won’t need for this purpose but which can provide a fascinating and mind-bending aside. For example, here’s a classic “paradox” that arises from special relativity:
if two observers are watching each other’s clocks as they move rapidly relative to one another, each of them will think that time is moving more slowly for the other, so each will expect the other to have aged less if they meet again. But they can’t both be right, so what’s going on here?
To even attempt to answer questions like this, we need a bit more of a mathematical framework for our relativity, so that’s what we’ll establish first, in this appendix.
Just to emphasise: this is an optional extra, slightly deeper dive into the theory. You don’t need this to progress to chapter 3 and beyond: so if you’re in a hurry to find out why E is equal to mc2 or to get stuck into quantum theory, feel free to skip it.