Let's assume I have a planet and the planet itself is made out of something solid.

Around the floating rock is a layer of gas, then a layer of liquid and then a layer of gas again.
Thus the sea floats in the air without any contact to earth.
Every layer is multiple kilometres thick

Is it possible that live evolves and survives inside the water layer? And what sort of liquid/gas would I need to use to construct a gas-liquid-gas combination?

The liquid layer doesnt touch the ground which is a mayor problem - materials that could be used as construction material or food aren't inside the layer.
Also because of the water shielt the climate will be really weird

My question is: Is it possible for life to develop inside this liquid layer? How would the creatures look and how would the concept need to be shift to make life possible?

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    $\begingroup$ The first question that arises is if it would actually be possible to have a gas layer below a liquid layer. $\endgroup$
    – celtschk
    Sep 12, 2015 at 18:45
  • $\begingroup$ Hi Jonas, welcome to Worldbuilding SE. To me there are a bit too many different questions in one. We usually like to focus on one point, and then ask follow-up questions. And there are a number of questions about Earth-like planets covered by water. There you'll probably find some answers that you might find interesting. $\endgroup$ Sep 12, 2015 at 18:45
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    $\begingroup$ You should start by asking if it's possible to have a layer of gas covered by water. It's an unlikely scenario but the answers could be surprising. $\endgroup$
    – Vincent
    Sep 12, 2015 at 18:47
  • $\begingroup$ Although the answer might be good, it's not recommended to accept the first answer that early. It's better to wait a day or two at least. Other people might be interested in answering but might change their mind seeing that the answer was already accepted. $\endgroup$
    – Vincent
    Sep 12, 2015 at 20:00
  • $\begingroup$ Yea, you're right about your point. Maybe i should wait til someone figures out how to make gas more heavy or offers an alternative woth similar effect to the ring of water $\endgroup$
    – BlueWizard
    Sep 12, 2015 at 20:04

1 Answer 1


This is a tough concept to pull off, there are several issues that you will need to account for.

Let's start with known natural observations, there is currently no known gas that has a density that is greater than liquid, the densest gas known is still 1/80 the density of water, which would be essential for water to float on it above a solid surface with a standard gravitational pull. Also with each of those layers being kilometers thick the pressure on any gas layer below the liquid layer would be immense forcing the gas to transform into a liquid or solid state.

That being said, when building a fantasy world you are more than welcome to alter any natural laws as long as you can make it believable to your audience.

As for evolution of life in such an environment, i would look to how life currently exists in our oceans, primarily focusing on the ecology of algae life and how it supports biodiversity. Using a similar concept with algae as a basis for the food chain you can build life-forms that get progressively more diverse and complicated the higher they are in the food chain. One other aspect to evolution of a life-form in this type of environment would be what factors would force modifications to its anatomy, being in an all liquid environment for example, would the life form ever have a need to develop legs that could sustain its body weight on dry land?

As for construction materials for a tool-using society in an environment such as this, i would look more towards living structures, something that could be grown or shaped to provide the materials needed. For situations that would need heavy metals, you would still have to solve for a way to either get the materials from either asteroids falling into the water or some volcanic activity forcing material up into the "sea" from below.

Climate is a very complex feature to account for, is your fantasy planet tidal locked? without a major landmass to provide a disruption to a current would the sea follow the gravitational path across the surface of the planet? would the gaseous layer below the "sea" affect the currents of the sea above? Would the major heat source come from a star warming the planet through an atmospheric layer, or would the heat source come from the planet's core, or both?

I would start breaking down your concept into a series of questions and try to answer each one, i know that it will spawn many others as it has for me, but clarifying them will help you to refine your idea into something workable.

  • $\begingroup$ Very fine answer. I appreaciate it $\endgroup$
    – BlueWizard
    Sep 12, 2015 at 19:40
  • $\begingroup$ I'm not writing a book or something. This sort of planet is just something that interests me on a casual basis. Thanks for the good answer. I'll mark it as answered and trash this weird idea of mine $\endgroup$
    – BlueWizard
    Sep 12, 2015 at 19:42
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    $\begingroup$ Read The Integral Trees & the Smoke Ring by Larry Niven. Short answer is yes. No planet need be involved. $\endgroup$
    – pHred
    Sep 13, 2015 at 15:54

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