1
$\begingroup$

Trying to create a planet with sulphur dioxide (which is heavier than oxygen I think) on a lower level and oxygen above it. Is this possible? Need something that is horrible on the bottom and want mobile fungi [yep, they have legs] scrambling up to get away from it into the oxygen. (So annoying to have to always use fungi or bacteria when you are looking for an extremophile. Fungi have been done to death.)

$\endgroup$
  • 2
    $\begingroup$ A planet full of fire breathing dragons that use sulfur as fuel. $\endgroup$ – Justin Thyme Mar 26 at 0:08
  • 2
    $\begingroup$ Sulfur dioxide relatively quickly oxidizes in presence of water. We need some explanation why free oxygen is present, but not the water. $\endgroup$ – Alexander Mar 26 at 0:32
4
$\begingroup$

Somewhat surprisingly, kind of yes. (If you ignore the issue of how you keep the SO2 from oxidizing to SO3, anyway.)

Usually, the answer to any question of the general form "can I have part of my atmosphere composed of X and a different part composed of Y" is "no, because gasses are all fully miscible. However, that stops being a problem if one of the components stops being a gas.

SO2 has a boiling point of -10C. Which means that at "high" altitudes, SO2 will condense. Now, that won't get rid of all of it, but it will significantly reduce the concentration of SO2 above the SO2 cloud level. So, you just need to make the planet cold enough that there is a significant amount of land above that altitude / below that temperature. -10C is fortunately well within the range of temperatures survivable by Earthlike life.

If you want to completely eliminate SO2 from the air above some point, you will need to go below -72C, which is far less compatible with macroscopic Earthlike life.

$\endgroup$
  • $\begingroup$ Wow! thanks so much to all of you. I will now attempt to get my tiny brain around all this and get back to you if necessary. Science wasn't my major. A boiling point at -10C??? May have to dump the gas idea. Just need a reason for these creatures to climb on top of each other getting away from something. Maybe the fire-breathing dragons. . . $\endgroup$ – Seairon Conway Mar 27 at 1:40

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.