By Jonny Lupsha, News Writer

Sir Patrick Stewart has returned to his most iconic role as a new Star Trek TV series began filming last week, ScreenRant reported. The iconic science fiction franchise has spawned over a dozen feature films and several television series since its inception in the 1960s by creator Gene Roddenberry. One of Star Trek‘s best-known subjects is that of parallel universes.

When Patrick Stewart returns to the small screen as Captain Jean-Luc Picard of the U.S.S. Enterprise, he’ll be reprising one of sci-fi’s best-known roles in one of its best-known intellectual properties. Star Trek has challenged its audiences for over 50 years, including portraying one of the first female African-American roles that was equal to her male and Caucasian co-stars. However, one particularly fascinating topic it visited several times—including in the Stewart-led show Star Trek: The Next Generation—was the theoretical idea of multiple universes, which, when combined, make up a “multiverse.” Let’s look at how it contributed to the so-called “many worlds” discussion in entertainment.

What Is the Multiverse?

In order to make sense of the concept of parallel worlds, it’s imperative to have a working understanding of the multiverse. “The most common way to understand what a multiverse is is in terms of alternate dimensions,” said Dr. David K. Johnson, Associate Professor of Philosophy at King’s College in Wilkes-Barre, Pennsylvania. “Consider the ‘block’ world view of time. It’s the collection of all the three-dimensional moments in time of our universe set into a four-dimensional block. To envision the multiverse, just envision a collection of such blocks stacked up in the fifth dimension.”

In other words, if you could pack the full history of the universe—past, present, and future—into a box that exists throughout time, the multiverse would be similar to an attic full of those boxes. However, each universe is different to a greater or lesser extent. In one particular episode of Star Trek: The Next Generation, called “Parallels,” Captain Picard finds himself traveling haphazardly from one universe, or box, to another. “It’s like the universe is a giant closed book and there’s a universe on every page,” Dr. Johnson said.

When Every Decision Matters

One popular theory of the multiverse is that there are an infinite number of universes, many of which differentiate merely by specific and seemingly innocuous decisions we make. How would that work? “If the outcome of quantum events have an effect on the macro scale often enough, two universes with the same starting point and the same laws could end up being considerably different,” Dr. Johnson said. “Suppose that the outcome of the physical processes in the brain that generate decisions are dictated by the outcome of quantum events. If so, two universes could be exactly the same up until the point that you make a decision but then diverge.”

The writers of Star Trek: The Next Generation knew this when they created the episode “Parallels,” which appears to depict exactly this idea with its characters Captain Picard and Lieutenant Worf as they go about a normal day at the mercy of the multiverse. “Upon his return to the Starship Enterprise, Lieutenant Worf starts to notice strange things,” Dr. Johnson said. “The cake he cuts at a party was chocolate, but then suddenly is vanilla. Captain Picard couldn’t make it to the party, then he’s there. As the episode continues, the differences become more extreme: the bridge’s control panels are completely different, Captain Picard is dead and Worf is the First Officer—the list goes on.” As Dr. Johnson explained, this jarring series of events has happened because while on a shuttle on his way back to the main ship Enterprise, Lieutenant Worf has encountered a quantum fissure in the spacetime continuum, which throws his life into chaos.

Ultimately, the Star Trek franchise has depicted plenty of fantastical scenarios in its half-century lifespan, but it has also touched on several thought-provoking notions of theoretical science and quantum mechanics. When Patrick Stewart returns to the captain’s chair, audiences can expect this trend to continue, if “Parallels” and theoretical multiverse theory are anything to go by.

Dr. David K. Johnson contributed to this article. Dr. Johnson is Associate Professor of Philosophy at King’s College in Wilkes-Barre, Pennsylvania. He earned a master’s degree and doctorate in philosophy from the University of Oklahoma. At Oklahoma, he won the coveted Kenneth Merrill Graduate Teaching Award.