Designing Alien life

[Robert_Moriyama]

For an interesting take on extremely-high-temperature lifeforms and how they might function, viz. Hal Clement's novel "Iceworld". (Aliens that evolved in conditions where sulfur and some metals are liquid land on Earth -- a place so unimaginably cold that the incredibly corrosive substance dihydrogen oxide exists in huge quantities in LIQUID FORM!) Can't remember what the aliens used for body fluids in place of water, but Clement (a.k.a. G. Harry Stine, I think) was considered a 'hard science fiction' writer, so his choice was probably a good one (at least by 1960s(?) scientific standards).

[Robert_Moriyama]

The following does not pertain so much to the design of the life form as it does to the development of their civilization:

Hmm... By "fire", I would assume you mean "heat to use in working metal or other chemical / mechanical / industrial processes", not necessarily "flame".

Underwater, you would have naturally-occurring geothermal* vents or hot spots (underwater lava vents?) and your aliens could have discovered highly-exothermic chemical reactions that either do not require oxygen or use oxygen present in the seawater... If the latter were to be confined in some kind of kiln or oven (so the heat was not quickly dispersed by conduction / convection), it presumably could reach temperatures sufficient to melt at least some metals or make them workable.

(*What would the word be for the internal heat of a planet other than Earth? Can't recall if they apply the term "geothermal" to other planets or not.)

The vent solution unfortunately carries with it the problem of uncontained heat and toxic concentrations of various dissolved materials. How would your aliens have learned to get close enough to use the heat without suffering from it and the unbreathable water? Whatever materials they were attempting to melt or work or "cook" would also be contaminated by the gunk from the vent, so this may not be a great solution to the problem (except as a "eureka" catalyst -- a prehistoric alien notices that odd things occur or can be found near (downcurrent from) such vents, and realizes that the heat and other stuff have unusual effects on various materials. They then go on to find ways to generate controlled heat, arriving at...

[Lester Curtis]

Underwater, you would have naturally-occurring geothermal* vents or hot spots (underwater lava vents?) and your aliens could have discovered highly-exothermic chemical reactions that either do not require oxygen or use oxygen present in the seawater... If the latter were to be confined in some kind of kiln or oven (so the heat was not quickly dispersed by conduction / convection), it presumably could reach temperatures sufficient to melt at least some metals or make them workable.

I see a problem here . . .

Once you get a piece of metal ore hot enough to forge (you would need a lava flow for that), you then have to remove the workpiece from the heat source to forge it into shape (using what tools, I wonder?) -- and then the surrounding water quenches it before you can work it. Also, think about trying to swing a hammer under water . . . add the problems of buoyancy degrading the leverage you'd get from being anchored in one place by gravity. The physiology and musculature needed to do these things under water would probably make a body that would not be ideal for maneuvering and propelling itself in that environment (like us).

An amphibious creature is a compromise; it doesn't make the best use of either environment. I'd suggest an evolutionary track that would have the creatures living on dry land for the majority of their lives, so they could do the kinds of work needed to establish technology. They might still have working gills, and perhaps just visit the sea to reproduce and/or gather seafood and other resources. Think about their senses, too. Eyes and ears need to work satisfactorily in both environments.

I think you want something like "The Creature From the Black Lagoon" -- but other forms are easily imaginable, such as a centauroid body with a big tail for swimming.

[Robert_Moriyama]

As noted, I suspect that the metal tools used by this civilization (if developed underwater) would at least initially be made from metals and alloys with relatively low melting points (where's my Chemical Rubber Handbook when I need it?) Extrapolating from human history, would this mean copper, tin, lead, leading to bronze? We might also expect ceramics, initially based on our water-breathing buddies building mud walls to shield themselves from heat and contaminated water flows (like a windbreak in the surface world) and discovering that these walls were transformed by heat into materials harder than any natural carapace or shell. For that matter, maybe their technology is based mainly on ceramics with minimal use of metals... (Speaking of which -- are you envisioning them as having any form of electrical or electronic gear? Developing THAT sort of thing in a highly-conductive 'atmosphere' would be a REAL challenge (although the presence of sea-life that generates its own electrical charge might suggest a biologically-based form of electronics...).

If our gill-breathers build themselves inverse SCUBA gear, it would probably be modeled on the shells of undersea creatures with exoskeletal armor. Of course, just having tanks of water for breathing would not allow much time without a continuous flow of oxygenated water, so the breathing apparatus must have some means of removing carbon dioxide and absorbing gaseous oxygen from the hostile above-water environment. (This would be less necessary, of course, if the creatures are true amphibians with both gills and lungs or analogous organs.

[Lester Curtis]

Nice point about the ceramics, Robert. Obsidian would be a natural discovery around undersea volcanoes . . . obsidian knives are sharper than any metal blade, and they might be able to work the material without too much trouble. ("Here, shark, are you hungry? Eat this!") Other kinds of ceramics can have some pretty awesome properties, as well. As to electrical stuff, they might find piezoelectric crystals to do things with -- just not sure what they'd do with 'em! Are there piezoelectric ceramics? I don't recall . . .