When we first stumbled upon the traveling salesman problem, we were dealing with a salesman who had a fairly easy task: to visit four cities in some order, as long as he visited each city once and ended up at the same city that he started in.

If you work with computers (or even if you don’t!), there’s a good chance that you’ve heard people talk about computers as just “a bunch of ones and zeros”. This was one of the few things I knew about computers before I got into software: it’s all just ones and zeros.

Tilted to the orbit of the Earth around the Sun – and so most of the time, the moon will pass above or below Saturn in the sky, and no occultation will occur. It is only when Saturn lies near the point that the moon’s orbit crosses the “plane of the ecliptic” that occultations can happen.