Sci-fi fans call it “sensawunda”, that awe and amazement that the best science fiction stories can inspire in us. The entire world felt it recently when scientists declared that observations of a distant star might have revealed an alien megastructure. Did inhabitants of the KIC 8462852 star system encase their sun in solar panels to harvest energy? Or was this our generation’s canals on Mars moment? The sensawunda effect is so powerful that, even with scant real evidence, we are swept into believing.

The unlikely cause of KIC 8462852’s strange emanations is speculated to be a partially constructed Dyson sphere. Imagine the Death Star from Return of the Jedi, in its partially constructed state, but on a scale large enough to swallow a star. Engineering on this scale is as far beyond human capacity today as building a skyscraper was to our cave-dwelling ancestors. Imagine the power of of a civilisation that can capture a star. Then imagine the drama that might stop the construction work partway, a very real war among the stars. There, that is sensawunda!

It was the physicist and mathematician Freeman Dyson who developed the “Dyson sphere” concept in the early 1960s. Like so many scientists, Dyson’s vision of the universe was in part shaped by the mythologies of science fiction. The idea that alien life might encrust its local star system with megastructures, both to gather energy and provide more habitable environments, was first postulated by Olaf Stapledon in his 1936 book Star Maker. Stapledon’s imagined history of the universe was paradigm-forming.

In the novel, stars are described as organic entities, creating life that then feeds off and destroys its star, so that “each stellar world became an increasingly hollow sphere”. The holistic and ecological themes are well ahead of their time, but even more so, Stapledon’s idea that life across the universe would repeat the same archetypal patterns helped shape everything from Star Trek’s vision of a federated galaxy to the scientific search for extra-terrestrial life. Stapledon’s “Dyson sphere” was a natural idea to explain KIC 8462852 because it was part of the inspiration for the search itself.

British author Arthur C Clarke was hugely influenced by Stapledon’s megastructres, and his stories are peppered with vast architectures both human and alien. Clarke’s collaboration with film director Stanley Kubrick birthed the mysterious monolith orbiting Jupiter that astronaut Dave Bowman describes as “full of stars”. But it was the 1973 novel Rendezvous With Rama that introduced Clarke’s most fascinating megastructure, a 20km-long, perfectly cylindrical spacecraft containing [SPOILER ALERT] an entire alien civilisation in hibernation.

Rendezvous With Rama, like Star Maker before it and, indeed, much of the most famous SF ever written, is almost entirely devoid of character or real human emotion. The crew of astronauts dispatched to investigate Rama are mere sets of eyes through which Clarke describes this alien world. But to an extent, this is integral to the sensawunda experience. What do petty politics and love affairs matter in the face of the universal mystery? There’s enough romance and soap opera to entertain the masses. SF explores higher things.

It’s perhaps this absence of character in megastructure stories that led reviewer Roz Kaveney to dub them Big Dumb Objects. Their bigness and dumbness was the satirical focus of JG Ballard’s 1982 story Report on an Unidentified Space Station. A team of astronauts arrives at the titular space station and begins exploring. With every update the estimated size of the station increases, from 500m, to a million miles, until, in a Borgesian twist, the crew realises the station is of infinite in size and in fact contains the universe:

We have accepted the limitless size of the station, and this awareness fills us with feelings that are almost religious. Our instruments confirm what we have long suspected, that the empty space across which we travelled from our own solar system in fact lies within the interior of the station, one of many vast lacunae set in its endlessly curving walls.

Not satisfied with poking fun at sci-fi’s fascination with megastructures, Ballard also had to trump everyone by coming up with the biggest of them all. But Ballard’s story is also a return to the core theme that energised his love/hate relationship with science fiction – that our sensawunda at the space out there is really about the space in here, and our deep-seated need to explore our own inner worlds. A need so profound that Ballard is right to invoke religion in describing it.

Star Maker inspires the same kind of awe as KIC 8462852 and its odd emanations. But what is it that sparks such emotion in us? There is no real evidence of any alien megastructure in our universe. But perhaps that itself is the key. In the idea of the megastructure we see the presence of other life, and of life older and more powerful than our own. In that regard our myths of megastructures are no different than myths of angels and gods in earlier ages: they provide us with hope that we are not alone.