Atmosphere on another planet

[Cloengaa]

I have been thinking. Our atmosphere is 78% nitrogen, 21% oxygen, 0.9% argon, and 0.03% carbon dioxide.

What if on another planet there were 58% nitrogen, 41% oxygen and the rest was the same as here. Would we be able to breathe and live there ?

And if we go even further so like 21 % oxygen, 58% nitrogen and 20.9 % argon would we be able to survive that ?

[Macavity]

Throughout geological time, the (Oxygen) composition of Earth's atmosphere
has varied significantly. Notable peaks in Oxygen content in the Carboniferous 
period... The time of the "Giant Insects" (Dragonflies etc.) when it was possible
for primitive breathing system to support such larger (non-lung) creatures... ? 



Higher Oxygen concentrations probably meant increased flammability... The
tendacy fir Natural Forest Fires etc. Certainly, before a certain Epoch, there
was insufficient Oxygen to support much "Life as we know it!" (Jim). ?

[Carbon Brush]

The ability to breathe non-standard concentrations of gases is fairly well understood by those involved.
Scuba diving, aviation and medicine are all examples of non-standard gas breathing.

It is not just the ratio of gases that needs to be considered, but the pressure, or specifically the partial pressure of each gas resulting from the mix.
 

[johnturley]

1 hour ago, Cloengaa said:

I have been thinking. Our atmosphere is 78% nitrogen, 21% oxygen, 0.9% argon, and 0.03% carbon dioxide.

What if on another planet there were 58% nitrogen, 41% oxygen and the rest was the same as here. Would we be able to breathe and live there ?

And if we go even further so like 21 % oxygen, 58% nitrogen and 20.9 % argon would we be able to survive that ?

Life would be able to adapt to various concentrations of the above gases, only if there was a sudden change over a short period would it cause problems.

John

[Anthonyexmouth]

i use 32% oxygen all the time diving, have used 38%ish too in the past. 

Oxygen used to be much higher level, it allowed the large land dinosaurs to exist. They'd probably die rapidly at 21%