I'm currently writing a sci-fi trilogy on an alien world with a CO2 and methane atmosphere. The natives have pottery but since fires cannot work on the planet, how would they harden the clay without heat of any kind?

Would say using an element like mercury be a possibility to leech the water from the clay to harden it?

The aliens are methane breathers and they eat hydrogen peroxide (in addition to carbon from plants and animals) for their metabolism- there's perchlorates in the water as well.They have a primitive technology- living in tribal areas.

Any ideas welcome!

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    $\begingroup$ The inhabitants of this world must have a metabolism; so why exactly doesn't fire work? After all, on Earth fire and metabolic reactions are of the same nature, just progressing at different speeds. Ceramics is not dry clay; consider the difference between unfired bricks (mud bricks, adobe) and fired bricks. $\endgroup$
    – AlexP
    Sep 4, 2017 at 7:41
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    $\begingroup$ Ceramic and other clay-based pottery, as we know it, needs heat; it is not just a matter of drying it up. At the very least "sun baking" is necessary to have (low quality) pottery. $\endgroup$
    – ZioByte
    Sep 4, 2017 at 7:43
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    $\begingroup$ Of course, fire can happen on this alien planet. Use oxygen as the fuel. This is the opposite of making fire In the Earth's atmosphere. $\endgroup$
    – a4android
    Sep 4, 2017 at 7:59
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    $\begingroup$ Hello and welcome to Worldbuilding. I can only repeat what others have said: pottery requires firing, else you only have dry clay that will dissolve when it gets wet. Firing is not about just making it dry, it is about changing properties of the dry clay. Also there is indeed a problem with the premise: if oxidation cannot take place, then how do you expect any kind of metabolism to take place on this planet of yours? $\endgroup$
    – MichaelK
    Sep 4, 2017 at 8:12
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    $\begingroup$ 2 Mg + CO2 -> 2 MgO + C $\endgroup$
    – user6760
    Sep 4, 2017 at 8:24

4 Answers 4


"cooking" the pottery is not done only for taking away the water. For that sun drying would be more than sufficient, but it is well know that sun dried pottery is way worse than fire cooked pottery.

By raising the temperature during the cooking you also allow chemical reactions to take place, transforming the silicates and other compounds into the pottery and make the material become more resistant.

Though they may lack fire, they might still have other heat sources, namely volcanic or radioactive areas, which are not fire dependent.


If you have mercury; you have a lens: Put it in a dish and provide a low spin, it will form into a parabolic lens that focuses sunlight. Large lens = hot hot focal point. The dish can actually be just dried non-porous clay. The focal point can be a built up rock, brick or dried clay oven, up on some platform above the lens, and the bottom of this oven can have a small hole in it so the focal point of the lens heats a rock that won't melt, but can get to many hundreds of degrees.

Other ways to focus the sun will work too, if you can polish anything to a reflective surface. I know you don't have glass for lenses (because you don't have the heat to make glass!) but as a note IRL arrays of glass lenses can focus the Sun to a point with enough heat to melt iron. It is just a matter of size.

The same will be true for parabolic reflective lenses; check out these Real-Life Solar Power Towers. A spinning dish of mercury cannot be oriented to track the sun. But given a reflective surface (which does not have to be image perfect smooth; just reflect most light), made of polished silver or other reflective metals, this same idea can work on a very small scale: Reflect a lot of light to an oven on a tall stand (made of some wood equivalent or if need be a stone tower with clay mortar), and it will heat up. Put enough light on it, and it can get as hot as a forge, help refine metals, create crucible steel, etc.

Trial and error will tell (or have told) your aliens which rocks, materials, and clay recipes can tolerate the heat.


Add a naturally occurring resin to the clay before forming. You can buy clay with a plastic resin that hardens in contact with air. I bought some a couple of weeks ago

Air Dying Clay


Its sand melting and binding ? So without heat and liquifying these elements- how to get the sand to bind?

Other sources of heat it is then:

So, possible are solar furnaces - light focused to heat up ceramics.

Geothermal vents- basically use lava to produce cook pots.

Other chemical reactions.. Metall fires are possible even without oxygen. Other chemical reactions can produce similar heat.

Finally, pyhsical trickery, like standing waves heat production:



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