But to do this, Johnson must model the entire Universe.
"We start with a multiverse that has two bubbles in it, we collide the bubbles on a computer to figure out what happens, and then we stick a virtual observer in various places and ask what that observer would see from there," said Johnson.
"Simulating the universe is easy."
ANALYSIS: Looking for the Thumbprints of Parallel Universes
Although you have to admire his can-do attitude, the team aren't simulating every atom, star or galaxy in the Universe; in fact, the computer simulation only models the largest scale structures and forces. "All I need is gravity and the stuff that makes these bubbles up. We're now at the point where if you have a favorite model of the multiverse, I can stick it on a computer and tell you what you should see," he said.
This is where, according to the researchers, their work is so important if we are to understand what is going on in the regions beyond our Universe.
For example, if we consider a collision-filled multiverse, Jonson's model predicts that observations of the cosmic microwave background (CMB) radiation should exhibit rings, or ‘bruises', where next-door universes are pushing against ours. The CMB is the ubiquitous (yet very faint) ‘echo' of the Big Bang that can be seen at the most distant reaches of the Universe. If there's some interaction with universal bubbles (as some multiverse hypotheses suggest), these circular bruises should be present in the CMB signal – -representing distortions in the outermost edge of our ‘bubble.' Through a brief analysis of CMB maps of the entire sky, it appears that these circular rings are not present, potentially disproving a multiverse filled with colliding universes. Or it at least suggests the collisions aren't happening now - perhaps the multiverse is in some quiescent state?