Excess oxygen is actually harmful to humans, but all the climate warnings are about losing oxygen, not nitrogen edit: but when we look for habitable planets, our focus is ‘oxygen rich atmosphere’, not ‘nitrogen rich’, and in medical settings, we’re always concerned about low oxygen, not nitrogen.

Deep sea divers also use a nitrogen mix (nitrox) to stay alive and help prevent the bends, so nitrogen seems pretty important.

It seems weird that our main focus is oxygen when our main air intake is nitrogen. What am I missing?

edit: my climate example was poor and I think misleading. Added a better example instead.

    • LillyPipOP
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      7 months ago

      My climate example was poor, I’m sorry. A better example of what I mean is that when we look for habitable planets, our focus is ‘oxygen rich atmosphere’, not ‘nitrogen rich’, though most of our breathable air is nitrogen and too much oxygen will actually kill us.

      • zeppo@lemmy.world
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        7 months ago

        I suppose because we don’t really use the nitrogen - it’s inert, unlike oxygen which is part of vital respiration. I’m no expert but it’s conceivable some other mix of gases could work as the inert portion besides nitrogen, but oxygen is required. Seems like it would take a lot of luck to find the right concentration though.

        • lolcatnip@reddthat.com
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          7 months ago

          Calling it “inert” is misleading. It’s involved in all kinds of chemical reactions that are essential for life (and lots of non-biological reactions, too). It’s only inert in the sense that most living things can’t use it directly from the air and rely on nitrogen-fixing plants and bacteria to make it into molecules we can use.

          • zeppo@lemmy.world
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            7 months ago

            Sure, I understand it’s one of the 3 basic plant fertilizers and plays a role in human biology. I’m referring nitrogen as a gas and its role in human respiration. It’s commonly referred to as an inert gas. I think that mainly refers to respiration and combustion.

        • Dharma Curious@startrek.website
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          7 months ago

          Now I’m imagining a planet with a helium atmosphere that’s breathable for humans. Best. Episode. Of. Star Trek. Ever. I’m envisioning TOS, super serious scenes where Scotty has fallen near dead, Kirk looks to Bones for some reassurance, and in Mickey Mouses voice Bones mournfully tells him “He’s dead, Jim”

          • LillyPipOP
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            7 months ago

            This needs to be an episode of Lower Decks.

            e: and Boimler’s voice doesn’t change.

          • zeppo@lemmy.world
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            7 months ago

            I think it could work? Not really sure. Probably sound enough scientifically for a 1st gen Star Trek episode.

            • roguetrick@kbin.social
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              7 months ago

              It would work in the sense that you could breathe it. It would not work in the sense that the gravity of a planet that actually holds a helium atmosphere (as opposed to it flying off into space) would be uncomfortable.