Recently, two new scientific models have appeared, both suggesting that parallel universes may be a reality. In one, researchers propose that the initial conditions of the Big Bang resulted in what they call a “Janus point,” in which particles expanded outward “in two different temporal directions.”
In another similar model, yet to be published, physicists propose a “more simplified” version that also points toward the existence of a mirror universe, one where time, from our perspective, would flow backwards. They refer to their model as the “two-headed arrow of time.”
These models, however, are not alone. There are other studies, ideas and proposed models (not to mention clues) that indicate we may actually exist in only one of many parallel universes. Here are four more of them.
Disclaimer: Some of these ideas may be wrong, and some of the older ones may very well have already been discarded. I’m simply sharing them here to highlight a handful of science’s current discussions on the possibility of other worlds.
2007 – Are some black holes “portals” into other worlds?
Physicists in 2007 proposed that many objects in space that appear to be black holes may actually be wormholes. And while the common idea of a wormhole is generally a kind of shortcut through spacetime (like a hole in a folded up sheet of paper), they could also be gateways into other universes.
In a 2007 article titled Could black holes be portals to other universes, New Scientist highlighted research proposing that some black holes may actually be wormholes. If so, and if we could survive such a journey, we could possibly venture into these wormholes and travel into “another universe on the other side.”
However, even traveling into a typical black hole could, given what little we truly know about black holes, lead you on a journey into a parallel universe. At a conference last year, Stephen Hawking raised this very possibility.
2007 – Time travel “shifts between different branches of reality”
It’s interesting to me that the article I just referenced by New Scientist also mentions the potential creation of microscopic black holes at future particle accelerators. This echoes an element of the John Titor story – his time machine functioned with the use of two microsingularities that allowed him to travel through time.
But it wasn’t just time, not entirely. He also claimed to have traveled through multiple worldlines – that is, multiple universes. This idea, while controversial, does have some support in the scientific community.
“Dr [David] Deutsch showed mathematically that the bush-like branching structure created by the universe splitting into parallel versions of itself can explain the probabilistic nature of quantum outcomes.” – Parallel universe proof boosts time travel hopes, The Telegraph
According to physicist David Deutsch, the existence of many worlds would allow us to “sidestep” the pesky notions of time travel paradoxes and other issues.
2011 – Our universe exists inside a bubble
Does our universe exist inside of a bubble, one of many? In 2011, two research papers detailed the search for “signatures of other universes” in the form of “bubble collisions.”
“Many modern theories of fundamental physics predict that our universe is contained inside a bubble. In addition to our bubble, this `multiverse’ will contain others, each of which can be thought of as containing a universe. In the other ‘pocket universes’ the fundamental constants, and even the basic laws of nature, might be different.” – Is our universe inside a bubble? First observational test of the ‘multiverse’, Science Daily
Cosmologists looked for certain patterns in the Cosmic Microwave Background radiation that could indicate “collision imprints” in our universe from these other hypothetical “bubble universes.” For a more recent look at these possible bubble collisions, here’s another short article from last year.
2014 – Many Interacting Worlds
Finally, in 2014, scientists put forward another idea suggesting that not only do parallel universes exist, they also interact with one another. In this case, the strange quantum effects that we observe, they say, are the result of a “universal force of repulsion” between our universe and other nearby universes.
They call this model Many Interacting Worlds. You can read more about that one here.