There was a nice article at Salon published recently called “Rise of the Super-Earths.” It’s excerpted from the epically titled book, “The Life of Super-Earths: How the Hunt for Alien Worlds and Artificial Cells Will Revolutionize Life on Our Planet,” whose author, incidentally, has been quoted as once saying “Biology is the future of astronomy,” which is an awesome thing to say. So so far, so good, right? Anyway, the whole thing’s about planets outside of our solar system, larger than our own, that are within an hospitable distance from their respective suns; planets that could probably sustain life. Super-Earths. Check out this wonderful bit discussing the formation of planets:
“The preplanet structure—the ‘seed’ of a planet—consists of solids (mostly silicates) and volatiles (such as water and ammonia), with trace amounts of hydrogen and noble gases. Due to the energy of the accretion process and the constant collisions with large solid bodies, this seed is thoroughly molten. (Some of Earth’s internal heat is a relic of this process.) In this state the structure differentiates. Iron and siderophile elements (high-density transition metals that like to bond with iron) precipitate from the silicate mix and sink under their own weight to form the core in the center. The remaining silicate minerals will remain in a mantle with the less dense ones closer to the top. Volatiles that are left over after hydrating the mantle minerals will rise to the surface and atmosphere.
“Differentiation is an orderly and predictable process thanks to our knowledge of chemistry and mineral properties under pressure. Some super-Earths, the rocky ones, develop quite similarly, although the pressure in the mantle is almost tenfold higher and different varieties of minerals form. Other super-Earths, the oceanic ones, are totally exotic beasts, with oceans that are 100 kilometers deep overlying a dense hot solid water, called ice VII.”
Fucking hot water ice. That’s ice at temps of over 1,300°F. How about that? The rest of the article’s great, and you should read it, but that stuff about oceanic planets, and especially the ice thing, really peaked my interest. Not least because of my familiarity and love for Kurt Vonnegut Jr.’s novel, Cat’s Cradle (see ice-nine), but mostly because it’s just plain fascinating on its own.
After reading the Salon piece, you should then read the Wikipedia page for ice. For real. It’s a far deeper and more interesting subject than you’re probably thinking in your initial consideration of the topic. For example, there are apparently 15 different phases of ice, varied by a combination of pressures and temperatures. There are a few hot ices, and Ice-nine is actually a thing (but fortunately nothing like Vonnegut’s insidious, fictional variety). I also learned a bit about rotten ice, diamond dust, the lost, ancient practice of ice harvesting, and the existence of the term “ice famine.” And hey, did you know that at *super* high pressures ice is predicted to become a metal?