These days radioactivity has a seriously bad rep. The problems at 3 Mile Island, Chernobyl and Fukushima demonstrate that when nuclear goes bad it does so in a spectacular and lethal fashion. Catastrophic really doesn't do it justice. 

In a way this is a real shame because now just saying the word radioactive is enough to make people shudder.  It is not a subject people want to go near and yet from a physics point of view, radioactivity, its discovery and study has lead to the most amazing leaps in our understanding of the physical universe.  

I thought today I would do a bit of a general post on atoms and atomic nuclei, which got me thinking about radioactivity and nuclear magnetic resonance (NMR). The first of these, radioactivity, I am going to post about here, the other, NMR, I'll do in a post shortly.