Have been building a game called Rise: The Vieneo Province.

Vieneo is a terrestrial moon (all details can be found here) but we have an atmospheric composition we arrived on from another question:

N, SO2, O, and trace CH4, NH3, H2O, Ne, N2, CO... Nitrogen 98.4% 2589 mb Sulfur Dioxide 1.0% 26 mb and Oxygen 0.6% 16 mb

We have a lot of rain in the game (like subtropical environment on Earth) ... does that work with this new composition? Or do we need more water vapor in the air instead of SO2? Bear in mind the small hydrosphere of 13%. Thanks!

  • $\begingroup$ Any particular reason you made a new account? Pretty sure the mods will merge them for you if you ask nicely. $\endgroup$
    – F1Krazy
    Commented Jul 10, 2017 at 21:22
  • $\begingroup$ I am at work ... I guess I had two accounts somehow. I will definitely do that tonight, thanks! $\endgroup$ Commented Jul 10, 2017 at 21:36
  • 1
    $\begingroup$ Possible duplicate of Hypothetical Terrestrial Moon Atmospheric Composition Validation $\endgroup$
    – sphennings
    Commented Jul 12, 2017 at 19:33
  • $\begingroup$ @sphennings I don't think it's advisable to hit someone with a "duplicate" flag after their question gets closed and they try and write a better one. We encourage people to write better questions. $\endgroup$
    – Azuaron
    Commented Jul 12, 2017 at 20:33
  • 1
    $\begingroup$ @Azuarona no, we encourage people to improve their already existing questions. $\endgroup$
    – Vincent
    Commented Jul 13, 2017 at 0:30

1 Answer 1


With the combination of relatively low temperatures and small hydrosphere getting enough water vapour mobilised for regular heavy rainfall is pushing it anyway, you really want a warmer and/or wetter worldlet. If you want water in your rain instead of various sulfurous acids you need less sulfur dioxide but that doesn't really make that much difference in terms of the total percentage, up to 5% of Earth's atmosphere is water vapour at any given time so what you need is more "wiggle room" with those percentages.

  • $\begingroup$ I was told on the previous question that the SO2 needed to be 1% in order to explain the perpetually overcast sky. Are you saying the water vapor percentage of 5% (also taking some away from the Nitrogen) would give the same effect if we raise the temperature by a few degrees centigrade? I know all these things are interrelated which is why the original question got blown out of proportion! $\endgroup$ Commented Jul 17, 2017 at 1:00
  • $\begingroup$ @JasonReskin I'm not sure what moisture level you'd need to create permanent overcast, that largely depends on how thick an overcast you wanted, I do know that at 1% Sulfurous Oxides you are indeed going to get a permanent yellow smoggy haze cover and acid rain every day ending in a Y. Also raising the temperature will increase water vapour content in the air which will raise overnight temperatures as the air retains more heat. There are probably a lot of ways to get to what you're looking for, it sounds like you need start at effect not cause to me. $\endgroup$
    – Ash
    Commented Jul 27, 2017 at 13:08

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .