Idea is a cold planet with dense atmosphere (10 atm) where human can survive, while a liquid carbon dioxide would be possible. As the main component of atmosphere I think about neon, because it should not cause nitrogen narcosis: http://en.wikipedia.org/wiki/Nitrogen_narcosis#Causes Theoretically it is very popular element in universe (more than iron): http://en.wikipedia.org/wiki/Abundance_of_the_chemical_elements How to make up a process which would make it plausible? My idea so far: -No gas giant in system to suck all volatiles. -Planet migration inside after forming with plenty of volatiles. -Higher planet mass than Earth. -In order not to get a planet with 100% water surface, what about some mechanism to get rid of most of hydrogen. My only not violent idea is heavy UV light that would split water and let hydrogen escape. How to get it? (yes, I know short lived, massive star but wouldn't it send some hydrogen back when it blows its outer part at the end of its life?) Any ideas?