What if we breathed nitrogen?

[sailorhathor]

I'm currently working on making some changes to an original race of aliens that are very humanoid, as well as the mixed race children they had with Earthlings. For some variety, I was hoping to make it that these aliens breathed something other than oxygen, but I'm having a great deal of trouble figuring out what sort of changes that might make to

Comments

[sidheag]

Not really plausible I'm afraid. Nitrogen being chemically inert means it doesn't (in gaseous form) react with anything much. And you need it to, in order for respiration to work, ie achieve anything for the organism. So it's not explosions you need to worry about but the opposite.

[sailorhathor]

Thank you for the input! I'm finding through other comments that I may be able to create differences between humans and these aliens in other ways in terms of breathing, but breathing pure nitrogen simply will not work.

[elenbarathi]

We actually do breathe both oxygen and nitrogen - Earth's atmosphere is mostly nitrogen; a pure oxygen atmosphere would kill us as surely as a pure nitrogen atmosphere would.

Sorry; as sidheag said, an inert gas won't work for respiration. However, you can tweak the balance, if you like - that's what scuba divers do; check out this article.

Even if aliens come from a nitrogen/oxygen atmosphere, and thus are bio-compatible enough to breed with us, the components of their atmosphere wouldn't be identical to Earth's, so it only makes sense that there might be some difficulty adjusting to the change.

I don't think it would be plausible for humans to interbreed with beings who breathed anything other than nitrogen/oxygen in a mix relatively close to our own. The fetus has to survive on whatever the mother is breathing.

[beccastareyes]

We can breathe pure oxygen (and it's used in hospitals), but it's a lot more of a fire hazard because oxygen is so reactive. NASA used to use pure oxygen for its missions until the deaths of the Apollo 1 crew due to fire meant they decided that much oxygen is a safety hazard and switched to a mix of oxygen and nitrogen for launch. (Wikipedia says that pure oxygen was used once the Apollo missions made orbit, but at a lower pressure to match the amount of oxygen we breathe on Earth. The tricky bit is they wanted to keep total air pressure high on launch, but having 5 times the concentration of oxygen means even little sparks can turn into big fires.)

Nothing special about nitrogen except it's really common and nicely inert. I've heard of helium or other noble gases being used, though I can't think of a real-world example.

[elenbarathi]

I didn't say we can't breathe pure oxygen. I said "a pure oxygen atmosphere would kill us as surely as a pure nitrogen atmosphere would." In order for us to breathe pure oxygen, it has to be at extremely low pressure. But there wouldn't be a planetary atmosphere of pure oxygen in any case, because the stuff is too reactive.

There is a real-world example in the article I linked: "To go beyond traditional recreational depths, technical divers employ trimix, the general term for gas blends that replace much of the nitrogen and some of the oxygen with more benign inert gases, such as argon and helium." More information on trimix diving here.

[sailorhathor]

Thank you for this input! There are things here I never even thought of, and all the research people have presented here is really helping me tweak the idea.

[orange_fell]

There was an old post not about nitrogen, but about different concentrations of oxygen in earth's atmosphere. You might find some of the comments interesting: http://little-details.livejournal.com/3364015.html

[sailorhathor]

Those comments were extremely helpful! Thank you!

[sheenianni]

What they said above. You can breathe nitrogen in and out and it won't harm you (we do that all the time, as Earth atmosphere is roughly 78 % nitrogen, 21 % oxygen and 1 % some other gasses), but the problem is that we need oxygen for some important biological processes.

It's unlikely that any race would breathe nitrogen for the same purpose as we breathe oxygen, because nitrogen is very inert (non-reactive) - it definitely won't lead to any sort of explosion. You could in theory use other gasses, but then you run into the problem that the two races wouldn't be able to mix. Still the sci-fi settings give you some space and options; so if you insist on them breathing different gasses, then you can give that ability to the allien race (they can breathe oxygen and another gas, such as CO2 or maybe methane, depending on their surroundings). Alternatively, you could have the children be bred unnaturally involving (fictional) super-science methods and growing in incubators. Why is the ability to breathe two gases important?

[sailorhathor]

>> Why is the ability to breathe two gases important?

Actually, it isn't. I just thought that because they were mixed-species children, they would have this ability. But all my original ideas for this world came to me when I was in my 20's and not as interested in doing scientific research to make it more believable, so I'm trying to clean up as many of my goofs as possible now.

[beesandbrews]

What if they were just set up to breathe a different ratio of gasses to humans. Or if those gasses were at a different atmospheric pressure, so they needed an adaptation device to contend with otherwise breathable air? If they got too much oxygen, for example, then they got dizzy or it choked them, or it hurt their lungs? A hybridized alien/human could have a greater tolerance for Earth normal conditions

[sailorhathor]

These are the ideas I'm toying with now that the people here have brought them up. It does work a great deal better that the aliens do breathe oxygen, but perhaps at a higher concentration. I don't want the aliens to need a constant breathing apparatus while on Earth, but I would not object to humans needing an apparatus/domed areas where the air is made breathable for humans while on the alien planet. Most of the action will take place on Earth, so a constant need for an apparatus would get in the way.