Re: Enough liquid water on Mars to cover the surface to a depth of 1 mile

On 22/08/2024 21:19, William Hyde wrote:

Ernest Major wrote:

On 20/08/2024 21:22, William Hyde wrote:

>
In fact, if CO2 is the main greenhouse gas, the amount require to make Mars habitable also makes it uninhabitable. Nor can any such atmosphere hold enough H2O to matter.  Vast amounts of some neutral, stable, GHG are required. ArNe2 would be perfect, if only it existed. CFCs possibly, though they do eventually break down.

>
WikiPedia tells me that ArNe2 does exist; at 4K.

 And it's Ne2?  That was just a guess, or even less than a guess.

I thought that you'd picked on ArNe2 because greenhouse cases have to be at least triatomic (because you need bending modes for infra-red absorption), any known triatomic gas is problematic in some fashion at the concentrations necessary, and neon and argon are the commonest noble gases.
With CFCs a question that comes to mind - at the concentrations required in the Martian atmosphere is the equilibrium concentration of fluorine and chlorine from their breakdown acceptable. (I suspect that it is, as CFCs are extremely effective greenhouse gases.) At least one CFC (halothane) is an anaesthetic, so there's that to take into account as well.
--
alias Ernest Major