Pocket Universes

By Ray Tabler

Fair warning, there will be a lot of handwavium below. Because, we only know for sure about the one universe, so far. There may be others out there, or curled up into dimensions we do not perceive. Plenty of complex mathematics suggests such possibilities. But no hard evidence yet. Which doesn’t stop us from speculating about universes, parallel, perpendicular, alternate, and pocket. Why? For fun and profit, of course. So, silence the science fantasy alarm, and off we go.

Definition of terms, first. Size matters. An alternate, or parallel universe typically is a universe of roughly the same weight class as ours. That said, we don’t really know how big our home universe is. We used to have a firm idea of the boundaries and age. Then the James Webb telescope came on line, and upset the apple cart. But, generally speaking, an alternate universe is a big one like ours. A pocket universe is smaller than that. ‘Smaller” is a relative term. A pocket battleship is smaller that a superdreadnought battleship, but still too big to slip into your back pocket. Smaller still would be a pocket dimension.

I cannot set dividing lines between these classes. It’s similar to the case for buttes, mesas, and plateaus. All three are elevated, flat-topped geographical features. But, it’s difficult to tell whether something is a small plateau or a large mesa. The same is true for large buttes and small mesas. I suspect that there are some buttes which are larger than spots labeled as mesas. If you know of any, don’t rat them out to the geography police.

Sufficed to say that a pocket universe is more contained than an alternate universe. It’s cozier. Often, there’s only one way in or out. Although, that’s not a hard and fast rule. Certainly not if a back door makes for a better story. However, if you install two portals in a pocket universe, the argument could be made that it is nothing more than a particularly capacious and well-appointed worm hole. Something like those medieval bridges which had houses built on them.

A pocket dimension is smaller still, and tends to be portable. In Heinlein’s novel Glory Road, the characters carry around a convenient device called a “fold box.” It’s a piece of luggage which keeps folding out and out and out, to reveal an unending number of compartments. Heinlein doesn’t explicitly call the interior of a fold box a pocket dimension, but I think it fits the definition. Other examples would be Santa’s bag, or Doctor Who’s Tardis. The Tardis is famously “bigger on the inside,” with room for a kitchen, a garage, and a swimming pool, among other amenities.

Pocket universes can be rather large, as long as they’re smaller than ours. Phillip Jose Farmer’s World of Tiers series spreads its action across a group of artificially created pocket universes. As a matter of (in-series) fact, our universe is one of this clutch of synthetic realms. The stars really are lights affixed to some dark sphere somewhere beyond the Oort cloud. Other pocket universes in the series include a world shaped like a massive wedding cake (floating in a void), and a continuum of rapidly-spinning cylinders, which the characters have to traverse without looking up and getting dizzy. Among more normal-seeming spots like ours. One of those is the home of the builders of all the others. Which, is also an artificial pocket universe, with no clue who built that.

Christopher Rowley’s The Golden Sunlands is a novel about an alien race which abducts entire human colonies into slavery. The aliens retreat to an inside-out pocket universe, where the sun never sets, but only accessible through a dimensional portal. The aliens have been living there for ages. Enough time to have forgotten some of their own technology, retaining only the ability to leave and bring back human slaves to labor and fight unending, internecine wars between factions. Good story, but be warned. It ended on a cliffhanger. Perhaps there was to be a sequel which never came to pass.

Societal decay within a pocket universe is a common trope. Stephen Baxter’s story The Eighth Room, is about a far future when an alien race stashes the remnants of humanity in a hyperspace bubble to keep us out of the way. I recall that the place is set up like a zoo enclosure, with genetically engineered trees that grow sides of beef. Or, something like that. Over time, people forget the artificial nature of their existence. Nothing lasts forever. The pocket universe eventually starts to malfunction, and then shrink. The last of the human race is forced to evacuate through the portal back to our universe, which leads to a space station. The displaced humans have to deal with the new situation. A word to the wise, Stephen Baxter is a great writer. But he tends to be rough on his characters.

Probably qualifying as a pocket universe would be Ryk Spoor’s Grand Central Arena series. When humanity builds and tests a faster-than-light starship, it transports the ship and crew not to Alpha Centauri, but to a constructed universe. Artificial spheres float in an air-filled, smoke shrouded volume, with millions and millions of miles between spheres. Each sphere is linked to a different solar system back in the “normal” universe. Numerous alien races trade, visit, and sometimes conquer across this bizarre space. Upon reflection, the Arenaverse strains against the nebulous dividing line between pocket and alternate universe. She’s just so big that an intermediate category might be called for. Backpack universe? Conex universe? I’m open to suggestions.

The argument could be made that a computer simulation qualifies as a pocket universe. Think the matrix, in the Matrix movies, or the holodeck from Star Trek, The Next Generation. I can’t dismiss this notion out of hand, even if I retain some degree of visceral skepticism towards it. The sticking point would be the lack of physical presence in-universe. But then, physical presence in a pocket universe is a trick we, as a species, haven’t managed to pull off yet. Minecraft, literally clunky and rectangular as it is, holds the moral high ground of actually existing. Hard to argue with that. Something to think about.

So, I hope you enjoyed this whirlwind tour of pocket universes I can remember reading about or watching. It’s certainly not a comprehensive list. Only the ones I could think up snide remarks about.

END.