But possibly not quite in the way you imagined I meant!
Yesterday, my post included a fascinating essay from Patrice Ayme, 40 Billion Earths? Yes & No.
Thus it was rather fun to come across, more or less by chance, an essay from the Perimeter Institute for Theoretical Physics under the title of Is The Universe A Bubble? The essay describes how Perimeter Associate Faculty member Matthew Johnson and his colleagues are working to bring the multiverse hypothesis, which to some sounds like a fanciful tale, firmly into the realm of testable science. It opens:
Never mind the big bang; in the beginning was the vacuum. The vacuum simmered with energy (variously called dark energy, vacuum energy, the inflation field, or the Higgs field). Like water in a pot, this high energy began to evaporate – bubbles formed.
Each bubble contained another vacuum, whose energy was lower, but still not nothing. This energy drove the bubbles to expand. Inevitably, some bubbles bumped into each other. It’s possible some produced secondary bubbles. Maybe the bubbles were rare and far apart; maybe they were packed close as foam.
But here’s the thing: each of these bubbles was a universe. In this picture, our universe is one bubble in a frothy sea of bubble universes.
That’s the multiverse hypothesis in a bubbly nutshell.
It’s not a bad story. It is, as scientists say, physically motivated – not just made up, but rather arising from what we think we know about cosmic inflation.
Cosmic inflation isn’t universally accepted – most cyclical models of the universe reject the idea. Nevertheless, inflation is a leading theory of the universe’s very early development, and there is some observational evidence to support it.
It includes this interesting video:
and concludes, thus:
Meanwhile, the team is at work figuring out what other kinds of evidence a bubble collision might leave behind. It’s the first time, the team writes in their paper, that anyone has produced a direct quantitative set of predictions for the observable signatures of bubble collisions. And though none of those signatures has so far been found, some of them are possible to look for.
The real significance of this work is as a proof of principle: it shows that the multiverse can be testable. In other words, if we are living in a bubble universe, we might actually be able to tell.
– Erin Bow
So that’s blown the dust off your Saturday brains! You can go and hug your dog now! 🙂