Complex Numbers

Ice Sea Moons

Mostly just because I find this stuff fascinating, an article from Quanta:

    These Moons Are Dark and Frozen. So How Can They Have Oceans?  
The moons orbiting Jupiter and Saturn appear to have subsurface oceans — tantalizing targets in the search for life beyond Earth. But it’s not clear why these seas exist at all.

Usual disclaimer here: by "life" they mean probably simple life; complex life is unlikely, and sentient aliens are pretty much off the table. So let's not go imagining little green women.

For most of humankind’s existence, Earth was the only known ocean-draped world, seemingly unlike any other cosmic isle.

Counterpoint: we barely knew other worlds existed, what the stars and planets really were, and certainly not that they had satellites.

Now Earth’s oceans are no longer unique. They’re just strange. They exist on our planet’s sunlit surface, while the seas of the outer solar system are tucked beneath ice and bathed in darkness. And these subterranean liquid oceans seem to be the rule for our solar system, not the exception. In addition to Europa and Enceladus, other moons with ice-covered oceans almost certainly exist as well.

Really, it shouldn't be so strange that there's a lot of water out there. Even before they made these discoveries about outer solar system worlds, we knew that comets were largely water (in the form of ice).

These moons have existed in the frosty reaches of our solar system for billions of years — long enough for residual heat from their creation to have escaped into space eons ago. Any subsurface seas should be solid ice by now.

This sort of thing is, of course, what science is for.

These oceanic moons also offer a grander possibility. Temperate, potentially livable oceans could be an inevitable consequence of planet formation. It may not matter how far a planet and its moons are from their star’s nuclear bonfire. And if that’s true, then the number of landscapes we might explore in our search for life beyond Earth is nearly limitless.

I should note that I saved this article to my queue before I started playing Starfield.

“Oceans under icy moons seem weird and improbable,” said Steven Vance, an astrobiologist and geophysicist at NASA’s Jet Propulsion Laboratory.

And yet, defiantly, these alien seas remain liquid.

Side note: Every time these days that I see "defiantly," my assumption is that someone doesn't know how to spell "definitely." This is not the case here.

Now, it might seem, on the surface (pun intended), not so odd that an ice-covered moon would have liquid water underneath. After all, Earth is rocky (though much of those rocks are underwater), and yet has a molten core. Water is molten ice. But it's not that simple; we're talking about globes much smaller than Earth, worlds whose inner heat has had more of a chance to dissipate.

The article goes on to explain some theories that fit the evidence, but I won't go into more detail here. In summary, other factors produce heat, such as tidal friction.

As one of the prime candidates for under-ice life in the solar system is Europa (moon of Jupiter), the only thing I have left to note is that it's a good thing Arthur C. Clarke was writing fiction when he penned: "All these worlds are yours - except Europa. Attempt no landing there." Because telling humans they can't do something is a sure way to get them to do it.