Hey Myc! That's not a bad idea...cyclic ELEs!
I've read a couple of the Pern books- I don't like McCaffery's style enough to read them all, but I'm familiar with some of the thread's effects.
Asimov's "Nightfall" short story (expanded into a novel, BTW) has something similarly apocalyptic. In it, a planet in a multiple sun solar system (thus, having no night) experiences a total eclipse 1 time every 1000 years, driving the majority of the planet's intelligent beings mad with terror to the point that they destroy their civilizations overnight...
In such a campaign world, it could be something as simple and mundane as the planet passing through a huge asteroid field periodically...or that the planet's orbit passes through the tail of a supermassive comet- each would result in lots of debris raining destruction down upon the planet.
OTOH, periodic ELEs* shape the world a little differently than the unexpected ones: periodicity = predictability. Somebody- especially entities with long lifespans or people living within a stable political system- would be aware of the impending ELE, and prepare for it. This would be reflected in architecture, data-storage systems & materials, and so forth.
* I realize its primarily a question of time scale- technically, the Yellowstone basin supervolcano has a period of about a half-million years between eruptions. Predictable? Yes- but you need some serious scientific tools to be able to discern the pattern.
I've read a couple of the Pern books- I don't like McCaffery's style enough to read them all, but I'm familiar with some of the thread's effects.
Asimov's "Nightfall" short story (expanded into a novel, BTW) has something similarly apocalyptic. In it, a planet in a multiple sun solar system (thus, having no night) experiences a total eclipse 1 time every 1000 years, driving the majority of the planet's intelligent beings mad with terror to the point that they destroy their civilizations overnight...
In such a campaign world, it could be something as simple and mundane as the planet passing through a huge asteroid field periodically...or that the planet's orbit passes through the tail of a supermassive comet- each would result in lots of debris raining destruction down upon the planet.
OTOH, periodic ELEs* shape the world a little differently than the unexpected ones: periodicity = predictability. Somebody- especially entities with long lifespans or people living within a stable political system- would be aware of the impending ELE, and prepare for it. This would be reflected in architecture, data-storage systems & materials, and so forth.
* I realize its primarily a question of time scale- technically, the Yellowstone basin supervolcano has a period of about a half-million years between eruptions. Predictable? Yes- but you need some serious scientific tools to be able to discern the pattern.