It’s neat. In the book, the planet has two suns and every, say, 5000 years both suns line up with the single moon in a total eclipse. And this happens to a race that has never known dark. They go mad each time and destroy their civilization and it takes 5000 years to rebuild until the next eclipse.
Well, that’s not exactly what I was thinking of; but it sounds like a very interesting book :-)
-JT