re what planets are habitable in article jpg apr holly bnr co uk jpg bnr co uk jonathan p gibbons writes i would appreciate any thoughts on what makes a planet habitable for humans i am making asumptions that life and a similar atmosphere evolve given a range of physical aspects of the planet the question is what physical aspects simply disallow earth like conditions eg temperature range of k to k where temp is purely dependant on dist from the sun and the suns temperature atmospheric presure i know nothing of human tolerance planetary mass again gravity at surface is important how much can human bodies take day after day also how does the mass effect atmosphere i thinking of planets between and times mass of the earth i suppose density should be important as well climate etc does not concern me nor does axial tilt etc etc just the above three factors and how they relate to one another jonathan jonathan interesting questions some wonder whether or not the moon could have ever supported an atmosphere i d be interested in knowing what our geology environmental sciences friends think as for human tolerances the best example of human endurance in terms of altitude i e low atmospheric pressure and lower oxygen partial pressure is in my opinion to the scaling of mt everest without oxygen assistance this was accomplished by a team of mountaineers who trained at high altitudes for quite awhile i think a few months and then were flown by helicopter from that training altitude to the equivalent altitude on mount everest where they began the ascent of our planet s highest peak without oxygen tanks this is quite a feat of physiological endurance because if you or i tried to go to feet and exert ourselves we would probably pass out get altitude sick and could even die from cerebral edema so this is the limit of low pressure high pressure situations would be limited by the duration of time which it takes to slowly acclimate to a higher pressure skin divers would know alot about high pressure situations and could tell you about how they safely make deep dives without getting the bends some military experiments have put people under several atmospheres of pressure not sure what the high limit was because the papers aren t in front of me usually at a certain point the nitrogen in the air becomes toxic to the body and you start acting idiotic divers call this nitrogen narcosis those afflicted can do very dangerous and irrational things like taking off a diving mask and oxygen tank in order to talk to fish at feet under water hope any diving folk can elaborate on this matter as i am not a diving expert mars cannot support human life without pressurization because the atmosphere is too thin th our earth s atmospheric density in addition the mars atmosphere is mostly carbon dioxide basically you would need a pressure suit there or you d die from the low pressure interesting huh ken khayash hsc usc edu
