NASASpaceFlight.com Forum
General Discussion => Q&A Section => Topic started by: dunwich on 02/17/2022 05:58 pm
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Hello, I had some questions that mostly involve phase changes of supercritical CO2 on Venus (and also on terraforming Venus)
My first question would be that: Venus atmosphere at it's surface is not exactly a gas but a supercritical fluid,
this is because of the high pressure I wonder that if you would descend trough Venus atmosphere could you see the border where the atmosphere becomes supercritical? (is their a distinct layer) (has it been captured on camera?)
My second question would be on the 3.5% of venus atmosphere that isn't CO2 (mostly nitrogen) those remain a gas will the gas start behaving differently in a way that can be explained ELI5?
My second question would be if you shaded venus for a distinct period of time the atmosphere would start to cool.
the temprature would drop first drop from 737°K to 304°K (31°C the critical point of CO2)
I believe the surface pressure would remain sort of a constant however as the air cools it would become denser according to the figure below.
(see figure 2 from this link https://en.wikipedia.org/wiki/Supercritical_fluid)
it doesn't go quit as high as Venus 737°K but it does go up to 400°K in it (following the 90 bar line)
the air pressure should be roughly 200kg/m3 (0.2g/cm3) to 800kg/m3 (0.8g/m3) at 304°K
However if I google "What is the density of Venus atmosphere?" it states it's rougly 5.2 g/cm3, if I google "What is the density of earths atmosphere?" I get 1.2 kg/m3 (0.0012g/cm3)
So the question is what am I doing wrong here? (is the google answer 5.2g/cm3 wrong or am I converting incorrectly i used http://convert-units.info/density/kilogram-cubic-meter/1.2)?
My third question would be on the 3.5% of venus atmosphere that isn't CO2 (mostly nitrogen) those remain a gas will the gas start behaving differently in a way that can be explained ELI5? (if the density of the CO2 increases +4fold at 304°K will the upper atmosphere be more nitrogen or would the nitrogen get absorbed by the supercritical atmosphere at 3% in composition)
PS i changed the order of question 2 and 3 because I tought this would make it more clear
A fourth question would be if the atmosphere would continue to cool further, it would change from a supercritical liquid to a liquid would this phase change be called condensation (or is there a other term to go from supercritical to liquid)?
And as a final question
at a pressure of 800kg/m3 it would be pretty close to the liquid co2 density of 1101 kg/m3 would the (CO2) ocean start raining out, or would a sort of surface (gas/ liquid boundry) start apearing has anyone on youtube cooled a supercritical to condense supercritical CO2 into liquid CO2?
Okay one last question if you had a space suit that could withstand the enviroment and the surface temprature is slightly above the critical point and the air density is 800kg/m3 knowing that the density of water is 997 kg/m³ could you swim in the air? using human muscles and limbs (no wings attached)
I hope these questions could be interesting
And I than anyone that takes the time to explain them (or point out why they don't make sence and what would be better questions to ponder about)