Imagine a world where the Earth’s evolution ended up just slightly different from our own, a slight tweak of events that meant our distant primate ancestors missed whatever trick led them on the path to becoming homo sapiens. Imagine if that world existed parallel to our own. Imagine if more worlds existed, and each one was one micro-fraction different from the last, the change being somewhere in the distant past.
As you get farther and farther away from our “Datum” version of Earth, the changes become more and more pronounced, you eventually see changes in the ecology of the planet, where deer no longer look quite like the deer you remember. If you saw these changes in fast enough of a sequence even the geology of the planet would change before your eyes, tectonic plates would follow slightly different paths with every iteration, until finally the Earth is nothing like the Earth you once knew.
Now imagine if stepping into these worlds was as easy as hooking up a simple device that even a child could make to a potato.
The Long Earth is the first in a series of collaborative works between hard science fiction author Stephen Baxter and late comedy-fantasy author Terry Pratchett. As their bodies of work would suggest, these books start with a silly implausible concept (stepping between worlds thanks to a simple DIY project) and explores the ramifications in a more serious manner.
The book focuses on Joshua Valienté, a man who doesn’t require a stepper box to travel between worlds, and Lobsang, an artificial intelligence who believes he is the reincarnated soul of a Tibetan motorcycle repairman. The two end up on a journey that takes them across millions of different Earths, and exploring their increasing variations. Along the way they encounter Sally Linsay, the daughter of the man who invented the stepper box, and together they travel towards an ominous entity somewhere far down the chains of Earths that threatens to destroy them all.
The hard SF leanings of Baxter come through as the story looks at some plausible ramifications of exploring these Earths variants—what other life forms might have evolved had circumstances been slightly different? The further they travel from Datum Earth, the stranger these possibilities become.
The books also deal with logical political and social ramifications. Imagine if everyone had the ability to simply step into another Earth, untouched by man, and then back into our own? How do you stop someone from “stepping” into a bank vault, or the White House? How does a dictatorship keep its citizens from escaping? What would happen if you stepped to the Earth next door on the site of the great gold rush—one that had never been drained dry? (Hint: you’d find a thousand people had the same idea before you and that investing in gold futures was probably a mistake)
While the books are not dry and serious, they are not as inherently humorous as Pratchett’s work. Though Pratchett gets top billing, I suspect these are more Baxter’s stories with Pratchett and Baxter’s collaboration being more on the world building, though I could be wrong.
Pratchett’s presence can be felt throughout every story, however, often in the form of Discworld ideas being reapplied in a completely different setting. If I told you creatures called trolls and elves existed and you knew Pratchett was involved, it’s not hard to guess which species is good and which isn’t. They’re nothing like the trolls and elves of the Disc, but they do fit the mold other more basic ways.
The stories tend to play things straight, with comedy usually rising from the bizarre situations the characters encounter. As the books progress the cast of characters grows larger and the expeditions go deeper into the unknown. Humanity quickly colonizes the Long Earth, clustering in certain prime locations, which brings the question of how the US government (and other governments) will assert any kind of control over them, leading to the second novel, The Long War.
By the third book, The Long Mars, an economical way to travel to the Red Planet is found. Somewhere near Earth 2,000,000 there is one version where the Earth was destroyed in a cosmic collision, resulting in a “Gap” of space. From there the Earth space program finds a more economically viable place to launch a Mars mission—and explore its multiple variations as well. Two more books in the series, The Long Utopia and The Long Cosmos, take this even further.
My only complaint with the series is that with the growing cast and ambitious expeditions, the universe is increasingly stretched thin. You simply can’t comprehend the enormity of existence, and must focus instead on the characters and the islands of interest they happen upon. An infinite series of Earths must, by necessity, be reduced to a dozen key locations, with the rest whizzing by like a small town during a train ride.
This is a series of books that is as interested in exploring ideas as the story, and will appeal to readers who feel the same way. It uses the absurd to look at things seriously, and explore the universe in a completely unique way.