Yes, you could live on the moon. But whatever you do, don’t go into the tunnels...

The discovery of lunar tunnels is one giant leap for space exploration and mankind’s future on the Moon – but as every sci-fi fan knows, you definitely shouldn’t go down there, says Matt Potter

They mostly come at night. Mostly... (Copyright 2023 The Associated Press. All rights reserved)

That’s it, man. Game over. The news that a tunnel has been found on the Moon by Nasa’s orbiter satellites is kickstarting a public conversation that’s long been held in private: not just about terraforming the Moon, but about the rights of different countries, political forces – even individuals – to desirable lunar real-estate.

But could this discovery really lead to a world in which we inhabit the Moon? Should be getting excited? Packing boxes?

The answer is... yes and no. The breakthrough discovery – which confirms decades of speculation – could indeed help space agencies plan to stay there for significant amounts of time. The caves could be an important way of protecting those astronauts from the extreme environment on the lunar surface, which runs from -248 to +123 degrees Celsius.

The newly-discovered 150ft-wide, 250-ft deep accessible cavern beneath the smooth and landable Sea of Tranquillity on the Moon’s surface – likely a tube left by flowing lava – might just provide the shelter we need for a permanent Moon base. And when the alternative is unsheltered moonrock in 500 shades of grey, that fuzzy satellite image very quickly starts to look like the lunar equivalent of property ads in Country Life.

The strange thing is, we’d predicted it before we found it. And what’s particularly fascinating is that the predictors weren’t spectroscopy or lunar soundings, but pop culture. For centuries, our brains needed to paint some design, some life, onto the nightly blank canvas. And while science was still getting its shoes on, authors, artists and scriptwriters began describing the tunnel.

German writer Johannes Kepler first wrote in his 1608 book Somnium (The Dream) of a “race of daemons” who lived in its deeper shadowed parts. But the world-first reckoned with complex descriptions of these tunnels into the Moon in Jules Verne’s 1865 Une Voyage Dans La Lune (A Journey Into the Moon) in which the reptilian lunar population of selenites take France’s suited-and-umbrella-toting astronauts down into its labyrinths.

The 1902 silent movie adaptation was a worldwide smash for its SFX as much as its action, as audiences still agog at seeing moving pictures at all had their minds blown with psychedelic caverns, giant mushrooms and finger-like stalactites. On the moon was for spectators down on Earth. Into the Moon meant risking everything, even sanity.

Tunnels in the moon were dangerous, even sexy. And as the movie was filming in in 1901, Britain’s HG Wells wrote a spoiler hit, The First Men In The Moon. Again, Verne’s selenites, crawling from tunnels to eat strange growths on the surface. In one terrifying moment, the newly landed travellers, on what they think is a bare and uninhabited planet, hear a mysterious booming resonance from beneath their feet and suddenly realise they are not alone. The Moon’s subsurface is alive. It’s pure Whovian. It was also to come true.

In 1969, Apollo 12 astronauts Alan Bean and Pete Conrad set up a seismic experiment on the Moon’s surface, to test the consistency of the rock. Once back on Apollo 12, they steered the landing module to crash onto the lunar surface – its equivalent of 1 ton of TNT causing a “moonquake” that would reveal frequencies from the rock. But what they found surprised them initially.

The Moon appeared to be “only 60 per cent as dense as Earth”. Not only that – the Nasa write-up determined that “the moon was ringing like a bell”. Conspiracy theorists and dreamers, primed by selenites, seized on the description – simply indicating the difference in rock consistency, dryness, and so on – and extrapolated. “Hollow Moon” theory, one of the wilder conspiracy frameworks that has the Moon as anything from riddled with tunnels to being a giant tropical bottle garden – was born.

There’s a wonderful side to all this fantasy. Oliver Postgate’s Clangers first broadcast that same year, thrilling pre-schoolers and parents with the prospect of these knitted space piglets (not to mention soup dragons, froglets and the iron chicken) both living in moon tunnels – and being shy enough to draw the hatches whenever astronauts land and start poking about.

Moon tunnel fever gripped adults too. The space race years of the Cold War were a golden age of science fiction TV and comics, in which the twin exigencies of needing close-up, helmetless locations for actors – and using cheaply available wonder-materials like polystyrene for low-budget, reusable scenery – meant “action taking place inside planets” was very much the new “action taking place on planets”.

Physics is one thing, but the two immovables for alien worlds as we know them are production budgets and what the lead actor wants. (You can almost see a helmeted and visored Sigourney Weaver standing on the surface of a blank alien world and pleading to Ridley Scott, “Gimme something to work with, here.”)

Those reused polystyrene tunnels, those close-ups, have become the mainstay of Moon dread.

Where terrestrial horror has “down into the basement”, space horror has, “stay out of those tunnels!” We shout at the TV as Sigourney and her crew descend into subplanetary caverns in Alien (“they mostly come at night, mostly....”). Our legs go wobbly as David Tennant’s Doctor abseils into The Satan Pit to confront the ultimate truth, again, because we need them to.

No-one did more for the lunar interior tunnels than Dr Who. Its spring 1967 season featured humans being kidnapped from a Moonbase by cybermen through a series of mysterious tunnels. It has, once a season, returned us to tunnels under planets. It always guarantees a popular episode. It’s as if our imaginations can handle anything – horror, suspense, outlandish fantasy, dread – but pure absence.

A famous 1960s Soviet short story, Vera Inber’s “The Death Of Luna”, postulates the moment we realise its blankness and deadness as the moment we lose our childhood innocence; a kind of “Santa Claus is Dad” moment.

And so for now, I’ll sit and stare at that cave on the moon, looking into it from a safe distance of a quarter of a million miles or so away. I’m hoping for soup dragons, but you can’t be too careful. And if we do get there? I’ll be right behind you.