A summary of the possible issues if the planet stopped spinning:
Massive Destructive Inertia: Everything not fixed to the bedrock—people, oceans, and the atmosphere—would continue moving eastward at the speed of the Earth’s rotation (roughlyat the equator), causing utter destruction.
Unprecedented Weather and Oceans: The oceans would move toward the poles, where gravity is strongest, creating a single, massive continent around the equator and submerging high-latitude regions.
Six-Month Days/Nights: One side of the planet would bake under constant sun for six months, while the other would freeze in eternal night.
Extreme Climate Changes: Strong winds would blow from the hot, sunlit side to the cold, dark side, creating enormous, continent-sized storm systems.
Magnetic Field Collapse: The cessation of the earth’s rotation could stop the churning of the molten iron core, causing the protective magnetic field to collapse, leaving the surface exposed to harmful solar radiation
(not necessarily correct - I make no claims on the science)
By this definition, and for similar reasons, I imagine, I am a staunch Bell-Westian, only occasionally tempted by the hobgoblin of foolish consistency into imagining all sorts of Ken-Hitean drastic changes wrought by the events of previous campaigns set in the same world.
There is definitely a continuum between these types of setting. I’m currently playing in two campaigns that illustrate this.
The first is in a Ken Hite setting, The Day After Ragnarok. There’s been a substantial apocalypse, although its effects vary over different parts of Earth. It’s a very recent apocalypse, so that one can still create historical backgrounds. You just have to account for the apocalypse in the recent parts.
The second is in a gritty-realistic version of the England of Alfred the Great’s time. Almost everything in it is consistent with what is known of the history; the few things that aren’t are consistent with beliefs of the time. That’s quite Bell_Westian.
Something that’s implicit in the BW view is that history may get changed. This doesn’t happen whimsically, but if the PCs get information to Alfred that lets him win a battle he historically lost (or vice-versa), that will happen.
That’s something I try for, though it doesn’t always fit. At the very least, people will try to describe it in terms of the beliefs of the time.
Yes, I think this is the key one. One of the things I love to do is to model the thoughts of an actual historical person confronted by ahistorical weirdness. But this does mean I tend to put my games fairly close to the functional divergence point, so that I can have both “things are palpably weird now” and “things weren’t palpably weird during the formative events of major characters’ lives”.
While Arc Dream Publishing’s Wild Talents is not a perfect book and the system is not near as generically useful as they seem to have expected it to be, what it presents as Axes of Design for building superheroic histories is, I think, a useful meditation around this.
Their red axis is historical inertia and considers setting expectations for the possibility of, magnitude of, and amount of effort required to change history when starting from a given point.
Their worked examples I’ve stared at being Godlike which focuses on a fairly high historical inertia WW2, Wild Talents which proceeds from that setting with progressively lower historical inertia, and progenitor which starts from 1968 with a fairly low historical inertia so divergence crops up quickly.
I find Godlike and Progenitor interesting worked examples and Wild Talents less interesting (or maybe just less to my taste) once it hits 1960.