Do you ever feel like this universe is a podunk cosmos or one-horse reality?

Then you’re probably a fan of the multiverse: the idea that there’s a series of alternate universes existing sideways to this one. Though the term is mostly used in the realms of comic books and science fiction, theoretical science is also a home for multiversal speculation.

In fact, scientist Stephen Hawking was thinking about the multiverse not long before his death. As a Space.com headline puts it: “Stephen Hawking's Final Paper Proposes Way to Detect the 'Multiverse.'” On the same site, a 2014 article by Miriam Kramer begins with these stunning words, “The first direct evidence of cosmic inflation — a period of rapid expansion that occurred a fraction of a second after the Big Bang — also supports the idea that our universe is just one of many out there, some researchers say.”

In other words, hello multiverse. Fittingly, this is a word with multiple meanings and origins, ranging from heady philosophy to spandex-clad superheroes.

The first examples of multiverse are a lot older than you would think and not where you would expect. The earliest known use is by philosopher William James in 1895, who wrote, “Visible nature is all plasticity and indifference, a multiverse, as one might call it, and not a universe.” In the philosophical lexicon, this term means, as the Oxford English Dictionary (OED) defines it, “The universe considered as lacking order or a single ruling and guiding power.” It was another way of saying bonkersverse or choasverse. These uses didn’t suggest multiple universes but named the multiplicity and instability of this doozy of a cosmos.

A slightly older term looks like an antonym of multiverse but is actually a synonym: nulliverse. A philosophical argument by eclectic writer J. J. G. Wilkinson in 1847 described “an incoherent nulliverse, a whirl of fleeting sequences, and a delirious ‘chase of Pan’.” In 1882, philosopher William James discussed the possibility of “pure incoherence, a chaos, a nulliverse, to whose haphazard sway I will not truckle.” You have to admire a writer who lets you know with what they will not truckle. Anyhoo, like multiverse, nulliverse opposes the unity in universe.

The OED traces the idea of the multiverse as a bunch of parallel universe back to 1963 and a poetic sentence from a Michael Moorcock short story: “Jewelled, the multiverse spread around him, awash with life, rich with pulsating energy.” But the concept, if not the word, goes back just a few years earlier and has its roots in a sci-fi-influenced genre: comic books. In 1961’s The Flash #123—written by Gardner Fox and illustrated by Carmine Infantino—the multiverse was introduced to comics, and it hasn’t left since.

The multiverse was born from logistical problems caused by characters whose adventures just kept going on and on and on. DC Comics heroes such as Superman, Batman, Wonder Woman, Green Lantern, and the Flash had been introduced between 1938 and 1940. The first three stayed in publication continuously, with occasional updates, while the latter two were replaced by new versions. For example, the 1940-debuting Golden Age Flash Jay Garrick and his absurd helmet were replaced by the sleeker Silver Age Flash Barry Allen in 1956. Allen gained his powers in a science accident (like so many superheroes) and decided to call himself the Flash in honor of his favorite comic-book hero: Jay Garrick, the Flash.

A few years later, in 1961’s The Flash #123—“The Flash of Two Worlds”—it was revealed that Garrick wasn’t just a comic-book character, but that his adventures took place in a parallel universe. This world was eventually called Earth Two, but that was only the beginning of the DC multiverse, which consists of 52 universes, each with its own Earth. Since then, there have been endless stories at Marvel, DC, and other companies involving multiversal doppelgangers, team-ups, crises, wars, and other portal-hopping shenanigans. 

Writer Grant Morrison’s 2014 series Multiversity one-upped every previous multiverse story: each issue took place in a different universe that existed as comic books in other universes, taking that old Flash story to its logical extreme. FYI, our Earth us in the DC multiverse: it’s Earth 33. Multiversity has had a far more mundane meaning since the 1920s: a university with lots of departments but likely no access to alternate realities.

In science, the first known appearance of multiverse is a 1990 New Scientist article on wormholes, another sci-fi concept proven real: “The wormhole picture changes our view of the ‘origin’ of the Universe in a big bang, which is now seen simply as the event corresponding to our Universe branching off from the greater ‘multiverse’, to which we must still be connected by an umbilical wormhole.”

That umbilical wormhole—what a band name—has yet to be proven.

Neither has the multiverse, and it may never be, but what an intoxicating idea. An array of alternative universes answers every “What if?” imaginable. And the multiverse isn’t just bonkers comic-book science and even more bonkers real science: it’s an optimistic idea that reminds us, “It doesn’t have to be like this.” Imagining a multiverse in which you’re a doctor, ninja, astronaut, parent, or whatever can provide the inspiration to become one in this one.