Do we live in a multiverse? Daydreamers and science-fiction authors have pondered parallel universes for as long as scientists have described our own.
Our universe contains everything we know — from planets, stars, and galaxies to space and time itself. And it’s truly staggering in size, spanning some 93 billion light-years across, according to astronomers’ estimates. That’s more than our species could ever hope to explore.
But what if our universe isn't the only one? What if alternate universes are humming along undetected, right "next" to ours?