system
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human
[Firefly] What actually happened to Earth-that-was and how did people travel from the Sol system to the Verse?

It doesn't seem like they have any sort of FTL technology so did they use  stasis pods or generational ships? Did everyone leave Earth-that-was or did some remain behind? Also was the Verse the only destination for those that left or did others go to different solar systems?
gpt
Generational ships traversed the great expanse between Earth that was and the star systems we now call home.  Not everyone left Earth that was, not because they didn't try but simply because it was impossible to evacuate everybody.  Those that remained almost certainly died in the polluted mess that existed in the last days of Earth that was.

The systems that we call home were by far the most ideal systems for any of the ships that set out from Earth, for that reason the combined America-China mission chose their to set up.  Their allies tried to make it there as well but it seems that none succeeded because none have appeared since the settlement of the systems.

Other forces that may not have been welcomed as friends by America and China may have chose sub-par locations, however near the end most of the operations to escape Earth were not recorded and so we cannot locate any other operations or determine if they were successful until we begin to expand out from the systems we colonized, which isn't likely given how the Alliance is not exactly feeling prosperous right now.  I'd imagine it is more likely that if we do get out of our home systems it will be because the Alliance has fallen forever and we're trying to find a new place that we won't fuck up.