Starts With A Bang

The Multiverse Is Inevitable, And We’re Living In It (Synopsis)

An illustration of multiple, independent Universes, causally disconnected from one another in an ever-expanding cosmic ocean, is one depiction of the Multiverse idea. Image credit: Ozytive / Public Domain.

“It’s hard to build models of inflation that don’t lead to a multiverse. It’s not impossible, so I think there’s still certainly research that needs to be done. But most models of inflation do lead to a multiverse, and evidence for inflation will be pushing us in the direction of taking [it] seriously.” -Alan Guth

It sounds like an unprovable fantasy: the idea that our Universe is just one of countless others, dotted across an eternally expanding empty space separating them. That’s generally how we picture the Multiverse, with each Universe having its own hot Big Bang distinct from every other Universe. But this isn’t simply pure speculation, but the result of a few simple facts combined: our Universe is quantum in nature, inflation gave rise to the Big Bang, and quantum fields spread out in value over time.

Inflation causes space to expand exponentially, which can very quickly result in any pre-existing curved space appearing flat. Image credit: E. Siegel (L); Ned Wright’s cosmology tutorial (R).

Put those pieces together, and you’ll find that no matter how small of a region inflation starts off in, so long as you demand you get enough inflation to stretch our Universe flat, it will continue on for an eternity into the future. In some locations, inevitably, it will come to an end, giving rise to a hot Big Bang, but in many others, it will continue forever, separating the regions where inflation ends from one another for all time.

If inflation is a quantum field, then the field value spreads out over time, with different regions of space taking different realizations of the field value. In many regions, the field value will wind up in the bottom of the valley, ending inflation, but in many more, inflation will continue, arbitrarily far into the future. Image credit: E. Siegel / Beyond The Galaxy.

The Multiverse itself may not give rise to any observable, testable predictions, but arises as a direct consequences of other physical theories that have already been validated. Find out today why it’s inevitable.