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Comment by slg | Hacker News Reader

This is obviously a ginormous leap from this announcement and just a tangent sparked by it. The possibility of intelligent life developing on a world like Europa encrusted with what is effectively a miles think solid atmosphere has always been one of my favorite feasible sci-fi hypotheticals. Could you imagine how that would impact their culture? Would they even know there is anything on the other side of the ice? Them finding out about us would be even more world shattering them us finding out about them.

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The relevant sci-fi is the planet of Krikkit from the 3rd Hitch-Hikers book, Life, the Universe, and Everything. On that world, life evolved under a permanent blanket of cloud. At no point did they ever see the stars, or think that there might be something of interest above them. Until one day they sent up a rocket which penetrated the dust cloud, and for the first time they became aware of the rest of the universe.

Their response? “It’ll have to go.”

*Until one day a rocket crash landed on their planet (which caused them to create one in the first place)

For comparison, the furthest we've dug down is about 8 miles, and Europa's ice crust is estimated to be 10-15 miles. So, yeah that would be like us getting discovered by mole people from nearly twice the depth we're capable of reaching. It's fun to think about what a civilization on Europa would think about their world. You can go up, but it gets colder and the pressure gets lower. It'd be like trying to go to space, but you have to dig to get there. Perhaps the change in density would make any such upward drilling unstable and beyond their means.

No need to dig, you just melt yourself downwards. It's not exactly like digging through rocks on Earth.

Of course, barring collapse, the rocks won’t reform right above you as you go.

I wonder if one can apply some heat to the cable or wire dropping you down, and thus create a more open conduit.

Would liquid pool up as you melt the ice? I guess you'd need to pump it out. Is that even possible at that depth? The liquid might boil on the way up.

Your craft is denser than the liquid, so you just kinda drop through it and keep melting.

Doesn't the heat you have to produce increase as you go deeper?

In this case, the digging is from the perspective of a Europan living under the ice, and having to dig to go up.

What's the pressure like at that depth? That seems like it would have some implications to be dealt with

IIRC the pressure at the bottom of Europa's theorized ocean in similar to at the bottom of earth's ocean. The greater depth is compensated by the lower graviation field.

Oh this reminds me of Cixin Liu's (of the Three Body Problem fame) short scifi Mountain.

It describes an alien species that lives in the mantle of a planet. Their explorer finally dug through to the crust, when they were met with never before seen liquid water that instantly kills them as well as their (non water proof) equipments.

Fascinating short story.

I don't want to spoil anything but intelligent life that evolves under high pressure depth is explored in Project Hail Mary by Any Weir (author of recent popular culture book then movie The Martian).

https://en.wikipedia.org/wiki/Project_Hail_Mary

https://www.amazon.com/Project-Hail-Mary-Andy-Weir/dp/059313...

Thanks for the recommendation, seems excellent

Apparently the ring builders in The Expanse books were supposedly squids from an ice encrusted planet/moon.

It is an odd idea of how they’d even discover it. Assuming their natural habitat is a thermal vent on the ocean floor, they’d need pressure suits or probes to travel up to shell. Then they’d need to essentially create a Kola Superdeep Borehole in the sky, and there’s no obvious reason to do that, especially since drilling down into rock would be easier, and certainly more lucrative. (ie there aren’t any valuable materials in ice). This is assuming they don’t discover a 15 km deep fissure, which seems unlikely because I don’t think individual fissures discovered are that deep, all fissures are transitory, and probably randomly distributed. Sure a seismic network in the sky would could find evidence of fissures, but why are you building a seismic network in the sky?

It would be hard to tell if the rest of the universe even existed. No electromagnetic radiation or cosmic rays are going to make it through the ice. They'd have to get all the way to neutrino telescopes or gravity wave detectors to sense anything outside their ocean, and why would they spend the resources? Humanity could see our moon and it still took us thousands of years to get there.

Really they'd only do it if they managed indefinite population growth without poisoning their biosphere with waste products, and had to mine out the ice shell just for more living space. That would be tough: the equivalent would be if every square meter of the Earth's surface, including oceans, was as densely populated as Manhattan. That gets us up to 14 trillion people. Now make every building 10 km tall.

> there’s no obvious reason to do that

I think the reason would be that they’d realize they were in the middle layer of a multilayer ball.

My assumption is that at some point they would explore the entire ocean-floor habitat, discover the world is an oblique spheroid, and wonder what’s up. As soon as that happens the impetus becomes “obvious” and it’s a problem of technology.

Have you seen the movie Europa Report ^^ ?

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