From 2001 to the Hitchhiker’s Guide to the Galaxy, these awesome structures loom large over the genre, loaded with inscrutable significance

We humans love things we can’t explain. Witness the vast array of outlandish claims made about Stonehenge, from ancient calendar to alien stargate, when in all likelihood it was just a big clock or an early marketplace, a neolithic branch of Tesco.



When the unknown is also alien, the mystery only grows more magnetic. Think of that iconic opening to Stanley Kubrick’s 2001: A Space Odyssey: a family of apes wake one morning to find a black monolith looming over them; that had its origins in Arthur C Clarke’s short story The Sentinel. Did some super-advanced civilisation intercede in the early evolution of intelligent life on earth? Or was the monolith just filming a very special edition of Life on Earth?

We don’t know, and never find out. But this shiny, looming thing is just one of many Big Dumb Objects that have turned up in science fiction over the decades.

A term coined by critic Roz Kaveney and later popularised by the Encyclopedia of Science Fiction, the Big Dumb Object (BDO) is a unique selling point of the sci-fi genre. It can be a broad term – usually, they’re alien architectures, ranging from the man-sized to the planetary. BDOs either look extreme or unusual, and can often do extreme or unusual things: everything from lurking on a horizon to creating worlds. Usually, BDOs are plonked into plots to awe us with their majesty and mystery – really, they’re science fiction’s equivalent of a MacGuffin.

No other kind of storytelling goes in for spectacle quite so big, or quite so dumb as science fiction. But which is the biggest, dumbest object of them all?

No self-respecting galactic civilisation can call itself advanced until it can build its own worlds, right? Pick a convenient star system, select a goldilocks zone at the right distance for your species of life, and construct a ribbon of land in a ring around the whole system: boom, you have the mother of all BDOs – a ringworld.

The cover of Ringworld by Larry Niven (1970) Photograph: Ballantine Books

For many readers, Larry Niven’s Ringworld is the definition of all that is biggest and dumbest in sci-fi. About a quest to the edges of known space to explore a lost ringworld, the novel is arguably better known today as inspiration for the titular Halo of the hit video-game franchise. The much missed Iain M Banks also wrote about ringworlds, with mini-versions called “orbitals” being forged by the utopian future society in his Culture series. Banks created many other BDOs, such as his General Systems Vehicles, artificially intelligent spacecraft that are kilometres long, or his GSV Sleeper Service: a gargantuan version that slowly wanders the universe.

The Dyson sphere may be the most famous BDO of all: take the technology of ringworld and spin it out to create a sphere entirely enclosing a star. Now you have the ultimate solar cell, a near infinite energy resource that can power entire civilisations. (Although the trope is popularly named after astrophysicist Freeman Dyson’s 1960 paper, others have traced it back to Olaf Stapledon’s 1937 novel, Star Maker.) a great thought experiment that has popped up in many sci-fi stories, including House of Suns by Alastair Reynolds, The Rise of Endymion by Dan Simmons and Ann Leckie’s Imperial Radch trilogy.

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But for sheer inventiveness, no author has ever come close to Douglas Adams’s BDO in The Hitchhiker’s Guide to the Galaxy. Magrathea is one of Hitchhiker’s highlights: a world where bespoke planetoids are designed for the galactic 1%, which has left the galaxy littered with half-finished construction projects backed by shadowy investors (rather like the London skyline today).

Sci-fi gives us a gateway through which we can experience the wonder of our universe, and Big Dumb Objects are one key to opening that gateway. But while they can add spice to great sci-fi, too often authors use them as “idea crack”, exploiting the fact that there are infinite possibilites in speculative fiction to avoid explaining. Some can be fascinating to fans, but alienating – pun intended – to the majority of readers, for whom clinical descriptions of alien architecture rate low on the list of earthly pleasures. But wait, isn’t earth a giant computer commissioned by mice to find the question to the answer that is 42 … is it possible that we’re living every day on the biggest, dumbest object of them all?