The pressure and temperature near the surface of Venus are so high that its carbon dioxide atmosphere is a global ocean of a remarkable state of matter, a supercritical fluid, which fills any container like a gas but is as dense as a liquid.
I created a carbon dioxide pressure versus temperature phase diagram using Mathematica and its curated computable data. Phase transitions separate single-phase regions. Moving along the boiling-condensing curve from the triple point, the liquid and gas densities converge at the critical point, beyond which carbon dioxide can transition between liquid and gas without boiling or condensing! I added points representing the near-surface atmospheres of Earth and Venus, with the latter being in the supercritical region above both the critical temperature and pressure.
Only the Soviet Union‘s Venera spacecraft have landed on Venus’s alien surface, and only between 1975 and 1982. Their cameras provided us our first and so far only glimpses of Venus from beneath its supercritical “ocean”.
Carbon dioxide pressure versus temperature phase diagram, created in Mathematica. Carbon dioxide is a gas near Earth’s surface (blue dot) but is a supercritical fluid near Venus’s surface (white dot).
2 responses to “Venus’s Supercritical Ocean”
Nice post, John! Thanks for writing these. I always enjoy them.
Thanks, Mark! I enjoy reading your posts as well.