Earth's reality wasn't meant to happen—in fact, it was the product of a very bored goddess. She created an intricate latticework of six worlds to keep herself entertained, and because they were separated from the proper universe, she interconnected them. These interconnections help the worlds to survive, and they actually support the structure of the reality itself. You know, so it doesn't collapse and kill everyone.

Yes, if just one world becomes unanchored, they will all be crushed under the infinite weight of the original universe. She...didn't exactly think that one through. But, like any other responsible being, she developed a plan.
[From itch.io]