Thank you!
So, basically (3) was almost completely wrong, and (1) missed the fact that “ocean” doesn’t mean quite the same thing everywhere.
Could you explain (2) a little bit? I see in Earth seawater there’s about 15 times more NaCl by mass than other solutes. Is there an obvious reason for that, and is that Earth-specific?
I honestly don't know much about relative salinities of terrestrial versus Martian prospective oceans. I do know however that everywhere that's been closely sampled so far by rovers and landers has had lots of perchlorate (Cl O4) salts in the soil, sometimes up to 0.5% of the mass. This can form when chloride salts react with surrounding minerals under the influence of ultraviolet light... nobody is terribly confident yet about what actually happened there to make them given that these results are new since the Phoenix lander and Spirit and Opportunity, ...
r/Fitness does a weekly "Moronic Monday", a judgment-free thread where people can ask questions that they would ordinarily feel embarrassed for not knowing the answer to. I thought this seemed like a useful thing to have here - after all, the concepts discussed on LessWrong are probably at least a little harder to grasp than those of weightlifting. Plus, I have a few stupid questions of my own, so it doesn't seem unreasonable that other people might as well.