Whether you, yourself, live in just one of an endless array of alternate universes is a topic of actual debate among physicists, even sober ones. But when it comes to fictional worlds, multiverses have taken over, from the Marvel Cinematic Universe (which, come to think of it, might have to change its name), most recently with Dr. Strange in the Multiverse of Madness, to this year’s Everything Everywhere All at Once, in which infinite Michelle Yeohs grapple with life’s infinite tragedies. 

The appeal of the idea to storytellers and their corporate patrons is obvious. How else would you get Tobey Maguire, Andrew Garfield, and Tom Holland to all play Spider-Man in the same movie? How else would you be able to cram Patrick Stewart’s Professor Xavier from 20th Century Fox’s X-Men movies into the MCU? On one hand, the concept opens the door for wilder storytelling; on the other, it allows for endless iterations of the same characters and a doorway to painless reboots. There are always more Spider-Men out there. “Basically, it’s Diet Coke and original Coke,” says legendary comic-book writer Grant Morrison, who’s written more than their share of multiverse tales. “It’s the same thing, but just different enough that they can resell it to you.”

The many-worlds concept has long been a sci-fi staple, well before scientists began exploring it in earnest. H.G. Wells touched on the idea in the 1923 novel Men Like Gods, and Jose Luis Borges wrote of parallel worlds in the 1941 short story The Garden of Forking Paths. It was the writer Michael Moorcock who first applied the term “multiverse” to the construct, in his 1963 story The Blood Red Game.

In comic books, parallel worlds were originally best known via Marvel’s rival DC, beginning with the landmark September 1961 Flash story “Flash of Two Worlds,” which introduced the idea of an Earth-1 and Earth-2, each with its own set of heroes. By 1985, DC editors became convinced that its many alternate worlds — including one where the Nazis won World War II, at least two where all of the superheroes were cartoon animals, and one where all the heroes were villains and Lex Luthor was the only good guy — were too confusing for new readers. DC downsized its cosmos with Marv Wolfman and George Perez’s apocalyptic miniseries Crisis on Infinite Earths, only to shrug and reintroduce the multiverse later. (In 2019 and 2020, the so-called Arrowverse DC shows on the CW Network attempted their own universe-merging Crisis on Infinite Earths, only to end up following the same path as the comics — their multiverse is already back, with the showrunners of that network’s Superman and Lois recently confirming that it takes place in a separate reality.)

Marvel ushered in its own multiverse concept back in 1971, and it’s become a larger part of its storytelling this century, including the original comic-book Spiderverse storyline in 2014. Of course, the idea has also popped up in the usual nerd-friendly venues over the years, from Doctor Who to Star Trek (in the Mirror Universe, Spock is not only evil but also has an unflattering goatee, while J.J. Abrams’ Star Trek movies take place in yet another branched timeline) to the underrated 2000s TV series Fringe.  

In 2022, multiverses are so mainstream that movies and TV hardly have to explain them anymore. It’s hard not to connect the concept’s spread with a prevailing sense in recent years that, here on this Earth, we’ve slipped into what Community called “the darkest timeline” — that, in the face of cascading calamities from Trump to Covid to climate change to Julia Fox, we are in the worst of all possible worlds. Which, in turn, creates a powerful yearning for the possibility of better ones. 

The trend isn’t slowing down. There have already been two separate multiversal Spider-Man movies: 2018’s Into the Spider-Verse, which got there first, and last year’s Spider-Man: No Way Home. Next year will bring a sequel to the former movie, Spider-Man: Across the Spider-Verse. And over in Warner Bros.’ DC Comics cosmos, The Flash, due in 2023, will belatedly drag the cinematic versions of the DC characters into their own multiverse, with both Ben Affleck and a 70-year-old Michael Keaton popping up as incarnations of Batman.

For Warner Bros., which is dealing with Flash star Ezra Miller’s endless series of arrests and scandals, the multiverse may be a salvation: Execs there are almost certainly at work scouring various realities for one where Flash can be played by a less problematic actor.

This piece appears in Rolling Stone’s annual Hot List, in the July-August issue of the magazine.