Cosmology and quantum physics both offer tantalizing possibilities that we inhabit just one reality among many. But testing that idea is challenging.

If true, the idea would blow past one of physics’ most sacred limits: that parallel versions of reality can never talk to ...

The universe is a strange, beautiful place—rich with possibilities and governed by the odd rules of quantum mechanics. One of the most mind-bending ideas from this realm is the many-worlds ...

Pick up any science fiction book from the 1960s, and you’ll find parallel dimensions explained through magic portals or mysterious machines that work “just because.” Today’s readers want stories that ...