How is living in space meaningfully different from living in a submersible in the ocean (apart from the view)?

You would think we would get really good at the latter before going after the former, and yet I see no interest from people wanting to live in a (shallowly submersed) submarine. It would also be an order of magnitude less expensive and dangerous.

Heck, we can barely build permanent settlements in many places on Earth like Antarctica and deep inside many deserts. And, here we have 1G gravity, 1bar breathable air pressure, a magnetic field and shielding from radiation. We don't have any of that outside of Earth.

If we can't build, say, a 10K-person inhabited city on the south pole, how can we even imagine we can build it on the moon or Mars?

Can't agree more. There needs to be something like, a Manhattan sized building in the middle of Africa, with an air-cooled nuke in the center, and a fully self contained modern city, complete with suburban forests, inside. If that isn't going to work for any reasons other than for environmental protection, so wouldn't a Mars settlement.

> How is living in space meaningfully different from living in a submersible in the ocean (apart from the view)?

Just off the top of my head:

- different ability to re-stock

You could re-stock your submersible just about anywhere. You're going to have to do a lot more planning for your groceries when you go in space though.

- access to microgravity

This simply isn't available in a submersible. Microgravity provides some interesting manufacturing and biological capabilities.

- completely different pressure profiles

Combining different pressure environments in microgravity is particularly interesting to me.

- different instrumentation capabilities

It's not just the view -- the atmosphere plays merry hell with instruments when measuring the cosmos. And it does so in ways that just aren't relevant to underwater environments.

Gravity or lack thereof is a big one.

Have you seen what happens to people who live in zero gravity for long periods of time? It doesn't sound fun. I do get the appeal of wanting to experience it for a short period of time, though.

I would also say that scuba diving is probably the closest you can get to experiencing anything close to zero gravity on Earth.

Sure, living in zero G for a long period of time is not good for you.

You asked how space was different from a submersible. I gave you one difference, you expanded on that to a second.

Any space colony intended for long term habitation would create artificial gravity through centrifugal force. It's completely doable using materials sourced from the Moon and near-Earth asteroids; there are design studies dating back over fifty years.

>Having people in space would solve a lot of Earthly problems

Which ones?

Like literal unlimited space?

Global population growth is still measured in the tens of millions. We're a ways off from launching anywhere near a meaningful number of people into space in terms of current terrestrial population.

resources, experimentation with deadly technologies, etc.

Escape proof prisons.

s/Having/Ejecting