ELI5: what is the multivers

What is the multiverse?

Imagine our universe is like one video game, but there are infinite other video games running at the same time in parallel universes [2]. Each one is its own complete world with its own stars, planets, and rules [5]. We can't see or reach these other universes, but some scientists think they might exist beyond what we can observe [4].

Why do scientists think it exists?

Some scientists believe that every time something could happen in our universe, it creates a branch where that thing actually does happen in a different universe [1]. So there might be universes where you made different choices, or where dinosaurs never went extinct [1].

What makes it different from our universe?

Our universe is everything we can see and measure around us—all the stars, galaxies, and space [3]. The multiverse is the idea that our universe is just one tiny piece of something much, much bigger that contains many universes [5].

Do we know it's real?

Right now, the multiverse is just a theory that physicists think might be true, but we don't have proof yet [4]. We can't see these other universes, so it's really hard to test whether they actually exist [4].