“Star Trek.” “Inception.” “The Matrix.” Even “Buffy the Vampire Slayer” leveraged the idea of an alternative universe to create compelling stories. Are these alternate (or parallel) universes nothing more than sci-fi worlds, or are they grounded in scientific reality? If so, could inter-universal travel agencies ever emerge to offer round-trip tours of parallel points of interest?
Alternative Universe Basics
Not surprisingly, scientists can’t agree on alternative universe theory, often called multiverse theory. Physicists like Alexander Vilenkin of Tufts University suggest that the Big Bang led to rapid inflation that’s not constant across the universe. While inflation has largely ceased within our cosmological view, some remote areas of the universe are still expanding, in turn driving the creation of “bubble” universes that quickly expand and begin to move away. Theoretically, it should be possible to observe evidence of a collision between our universe and another.
According to Live Science, other experts argue that the potential number of universes is much smaller than the 10500 predicted by string theory because many of them won’t have the requisite amount of dark energy to drive universal inflation, while others will collapse under their own weight. Some theorists posit “daughter universes” — new universes created every time a choice is made — that see us constantly traveling to alternate versions of reality without realizing it, said Online Star Register. For the purpose of potential travel, however, two broad categories exist: outer and inner universes.
Outer universes exist outside the human mind. “Star Trek’s” mirror universe is a good example of a daughter universe gone awry; differing choices in the past led to a universe in which humanity didn’t form a benevolent space-faring federation but a capricious and malicious empire. Characters periodically travel to this universe using either transporter technology or, in the show’s most recent iteration, the so-called “Spore Drive.” An 1884 story by Edwin A. Abbot called “Flatland: A Romance of Many Dimensions” took another approach by suggesting a living, breathing universe with only two dimensions.
In addition to sci-fi worlds that exist beyond the stars, movies such as “The Matrix” and “Inception” suggest universes that are a product of human consciousness. In “Inception,” the lead character specializes in infiltrating people’s dreams to retrieve important information by using the phenomenon of “lucid dreaming,” which makes it possible to recognize you’re in a dream and control your actions. The film ends with the protagonist being reunited with his children — but fades to black before confirming if he’s in the real world or still dreaming.
“The Matrix,” meanwhile, features an apocalyptic universe where humans have been conquered by intelligent machines. The machines use mankind as batteries, simulating a familiar Earth reality where humans are actually trapped in gel-filled cylinders and connected to a global power network. This ties into the notion of Simulation Theory; as Fast Company noted, it’s possible that our universe is nothing more than a simulation run by advanced aliens or future humans — we may be the inner universe of some other civilization.
Making the Big Trip
Potential for parallel universes? Check. Multiple interpretations of what constitutes a parallel universe? Check. But is it possible to make the trip?
When it comes to inner universes, maybe. Penn State University noted there is some science tied to lucid dreaming, but permanently inhabiting that state is problematic since human bodies need food and water to survive. As for a simulation-type universe, we may already be trapped inside.
Traveling to outer universes may be more problematic, despite new research from the University of Durham, which suggests a wider variety of life-supporting universes than previously thought — their theoretical models show that “adding dark energy, up to a few hundred times the amount observed in our Universe, would actually have a modest impact upon star and planet formation.” So what does travel look like? It’s not transporters or spore drives: According to Futurism, theoretical physicist Michio Kaku suggests our universe will eventually wind up in a “big freeze” as expansion slows and stops; combined with technology, this may allow inter-universe transport. Neil deGrasse Tyson, meanwhile, says it may be possible to easily move from universes with more dimensions to those with less — we may already be doing so without realizing it.
Sci-Fi Worlds Roundup
Do other universes exist? Probably. Can you book a trip? If they’re inside your head — or if we’re already in a simulation — yes. Outside is more difficult. While we may be constantly traveling through daughter universes, “Star Trek”–like inter-universe trips won’t show up on travel websites anytime soon.