N2 is (mostly) inert when it comes to respiration. What your body needs is oxygen and low concentrations of anything that might also be metabolically active. For scuba diving, N2 is used to dilute the oxygen and is used specifically because of how non-reactive it is. At high concentrations though, it can result in nitrogen narcosis - helium is sometimes used as the diluent gas instead to mitigate this.
As far as habitability is concerned, atmospheric nitrogen is essential for life on Earth at least, as it’s a major part of the nitrogen cycle (specifically, nitrogen fixation). Without it, we wouldn’t have nitrogen-containing organic compounds like amino acids (and, therefore, proteins), at least not nearly in the same quantities that we currently do. This doesn’t mean it’s essential for life outside earth, but it is for life as we know it, so its presence should increase our credence (if only a little) for whether a given planet is habitable or not. However, when looking for signs of life, it’s better to look for atmospheric signatures that are heavily influenced by life, rather than just those that facilitate it. The oxygen in Earth’s atmosphere was largely produced by life, and so its presence in the atmospheres of other planets would be a good (though not definitive) indication of habitability.
Nitrogen is usually in the form of N2 and is very stable. We don’t really do much with this form of nitrogen because chemistry is hard so with each breath it just hangs around. The oxygen on the other hand js readily absorbed and used, converting it into CO2. We have to remove the CO2 to prevent toxicity and add O2 to prevent suffocation.
Somewhat tangential, but I’m reminded of that “viral” email that made the rounds back in the day.
An e-mail that circulated around the internet about 7 years ago claimed that this is true by stating “Aoccdrnig to rseaerch at Cmabrigde Uinervtisy, it deosn’t mttaer in waht oredr the ltteers in a wrod are, the olny iprmoetnt tihng is taht the frist and lsat ltteer be at the rghit pclae. The rset can be a ttoal mses and you can sitll raed it wouthit a porbelm. Tihs is bcuseae the huamn mnid deos not raed ervey lteter by istlef, but the wrod as a wlohe.” It turns out that many of the claims that are made in this e-mail are false; readers do display reading difficulties when reading jumbled text (Rayner et al., 2006, White et al., 2008) and no such research has been conducted at Cambridge University. However, the assumption that the exterior letters are more important than interior letters in lexical processing does seem to hold up in a laboratory setting.
While reading text your brain will bulk recognise what it interprets as common phrases and sentence fragments to build an internal lexical model to then interpret. After a while as you get more proficient at reading this becomes a mostly subconscious operation, which then hands concepts from what it’s read to your front of mind to further deal with.
If you blend contradictory common phrases together your brain will bounce through the phrase/fragment recognition part fine. Then it will trip over the lexical parsing of them, suddenly requiring a lot more mental horsepower to figure out what’s going on. Basically your front of mind task will be interrupted by your subconscious task basically going “what the hell is this!? I can’t make sense of this, you have a look” as it dumps a jumble of words on you.
For example, has anyone really been far even as decided to use even go want to do look more like? That phrase broke the internet about 10 years ago and it’s a pretty good example.
When we breath, we use the oxygen, but we do not use the nitrogen. The nitrogen can actually be replaced with another inert gas and the “air” is breathable. Thinking about diving specifically, nitrox is actually an oxygen rich (nitrogen poor) mixture. More extreme mixtures use helium in place of some nitrogen (and sometime oxygen depending on the depth).
In your body, the amount of oxygen in our blood is critical for survival. Having a lot of nitrogen is actually not good. Too much is what causes the “bends”, again related to diving.
When looking at exoplanet atmospheres, we look for oxygen rich because it likely indicates water. We believe that planets with a high amount of water are more likely to support life similar to ours. It is possible that another form of life exists that doesn’t need oxygen or water, but we know for certain that oxygen and water can support life.
Atmospheric nitrogen is useless to most life, as it’s extremely hard to break down into other nitrogen compounds. Certain bacteria are the exception, and they’re very important both to ecology and human agriculture (although less so since the Haber process was invented and artificial fertilisers became available). The other natural source of nitrogen compounds is lightning strikes.
Oxygen is completely the opposite. It’s unstable in an Earth-like environment (which is why fires happen), and if you find it in such an environment there must be something special producing it continuously. It’s not the only biomarker astronomers look for, either. There was a planet with insane amounts of a chemical called DMS found recently, and that’s just as eye-catching, if weirder.
Deep sea divers also use a nitrogen mix (nitrox) to stay alive and help prevent the bends
You’ve actually got that somewhat backwards. To go really deep you switch to heliox or similar. Nitrox is for intermediate depths where you need less oxygen than in the normal nitrogen-oxygen atmosphere, but nitrogen narcosis isn’t an issue yet.
The short answer is yes, you can trade one addiction for another and no, it doesn’t necessarily cause spiraling.
The long answer is yes, with a great deal of patience, you can condition yourself into just about anything. Breaking from an addictive personality is far from easy and requires a deep understanding of yourself and your triggers. Introspection and therapy aplenty. There can be relapses or worse if you try to hack together a treatment plan for yourself. Support groups can be helpful and leaning on friends and family, when possible, can make or break you.
Any addiction can be broken (the mental part, at least). The real hard part is you have to truly WANT it. You can’t magically wish discipline into existence where there was none before.
That said, I can’t seem to get rid of mine, but I acknowledge that my underlying problem is a profound lack of willpower.
For example: You eat too many potato chips and that’s bad for your health. Now you don’t go cold turkey on the snacks, but buy carrots instead and eat those.
How? You do it often enough. Do it for half a year, every other day and it’ll become the new habit.
That is entirely dependend on the substance, the original addiction, and the individual. Might it lead to a negative spirale? Sure. Addiction is destructive. Depending on the context pretty much anything can be done or consumed to the point of self harm. Probably don’t get into one on purpose like, a general rule of thumb.
Yes, he’s right that bringing the poles of two magnets together puts the system in a state of higher potential energy. And, yes, you could use this as an explanation for “why” the magnets repel by invoking the principle of minimum energy. You can even show that this results in a force, as a gradient in the potential energy is mathematically equivalent to a conservative force. I do think, though, that you can give further justification for the principle of minimum energy than he gives in the video, as it follows from the second law of thermodynamics (see Wikipedia article). Regarding the exchange of virtual photons and using this to explain how the electromagnetic force arises: I would avoid this entirely.
One side nitpick though: I wouldn’t say that the energy came from “the chemical bonds in the food [you ate]”, but rather the formation of new bonds as you digest the food. Chemical bonds are states of lower potential energy, so breaking them in the sense of separating the constituent atoms requires energy. It’s just that different bonds can have even lower potential energy and therefore release energy when they’re formed.
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