Hi All

Liquid CO2 does turn up even on Earth...

CO2 Bubbles

...in the deep sea of course. Carbon dioxide's critical temperature is a mere 31 degrees C, so I was surprised that it turned up at a hydrothermal vent, but then most of the water around the vent is at a mere 4 degrees.

I've read early Earth models with massive atmospheres like wet versions of Venus - I can imagine, thanks to Nick's work, weird H2O/CO2 stratified oceans in the early days after things cooled down enough too. A weird world indeed. In that era the Moon would be raising body tides in the mass of the Earth, flexing the crust and sloshing around the fluids through all those cracks. Trillions of mini-biochem labs churning out life's precursors... there's a reason why we metabolise CO2 as well as oxygen.

Wild speculation, but it shows how alien this world once was.

Adam