Datum Earth

Datum Earth is the only known of the Long Earths where Humans evolved and can be considered as our Earth in the The Long Earth series. Over the course of the three books, it passes from the dominant influence in colonising the Long Earth to being the distant colonising power that the Steppers inevitably rebel against. following a calamity lampshaded in The Long War - namely the eruption of the volcanic caldera under Yellowstone - Datum Earth eventually realises the relationship is changed and it is now pretty much dependent on the colony worlds for its survival.