(2019 Archived) - Argument XIII : The Abundance of Nitrogen on Venus vs. The Scarcity of Nitrogen on Mars.

 Having written this in 2019, and originally published in 2021.. when I was 15 and 17, there would be inaccuracies that I would correct here. Having removed it, I'm publishing  again, for sake of completion so that the efforts wouldn't have gone to vain: Pertaining to Nitrogen, most of this still stands true - will it be enough for a civilization though is debated on reddit, and said to be inadequate, requiring import. However, that's very far into the future. Numerous cloud-cities would be able to thrive with the Nitrogen that exists. 

The atmospheres of every world are unlike the atmospheres of other worlds – atmospheric composition differs from world to world. Here on the Earth we’re covered by a thick blanket, which is ~71% Nitrogen and ~27% Oxygen. Some planets, like Mercury, don’t have an atmosphere at all! The ice giants – a lot of hydrocarbons, and the other gas giants – a lot of Hydrogen.

Constituents	Composition – (Venus)
Carbon Dioxide	96.5%
Nitrogen	3.5%
Sulfur Dioxide	0.015%
Argon	0.007%
Water Vapour	0.002%
Carbon Monoxide	0.0017%
Hydrogen	0.0012%
Neon	0.0007%

                                                                                                             

The above table depicts the composition of the Venusian atmosphere, and reveals it to be primarily Carbon Dioxide at 96.5%, which is followed by Nitrogen at 3.5% ^[17]. If we were to compare it with the below table, depicting the composition of the Martian atmosphere, we find them to be quite similar; with Carbon Dioxide present at 95.35%, followed again by Nitrogen at 2.7% ^[15]. 

Constituents	Composition – (Mars)
Carbon Dioxide	95.35%
Nitrogen	2.7%
Argon	1.6%
Oxygen	0.13%
Carbon Monoxide	0.007%
Water	0.03%
Neon	0.00025%
Krypton	0.0003%

                                                                                                        

As we can see, Nitrogen is a common gas in both Mars and Venus – and quite an important one too! But although Nitrogen accounts for 2.7% of the Martian atmosphere, it quantity-wise very low in abundance. It is owing to the familiar reasoning of the Martian atmosphere being mostly a near-vacuum. But, what makes Nitrogen so important? It is owing to Nitrogen acting as an ideal ‘buffer gas’, to prevent ‘oxygen toxicity’.

Oxygen toxicity is a condition that arises with exposure to higher levels of oxygen, at normal or higher pressures. The body gets affected differently based on type of exposure: But, in outer space and alien worlds – it’s mostly long-duration exposure to higher oxygen levels in normal pressure. It could result in pulmonary or ocular toxicity, with “symptoms [that] may include disorientation, breathing problems, and vision changes such as myopia” ^[49]. Oxygen toxicity could be prevented via the presence of a ‘buffer gas’, which should be inert, not poisonous or detrimental to health, and affordable. The Nobel gases – Helium, Neon, Argon, Krypton and Xenon – are quite acceptable as buffer gases, because they’re inert, non-toxic and harmless-to-health. But they’re quite rare, expensive and unavailable. Thus Nitrogen – which is inert, non-toxic, harmless-to-health, and more readily available – is the most ideal buffer gas. After all, it wouldn’t be surprising that Nitrogen is the buffer gas here on the Earth!

The Nitrogen which occupies 3.5% of the Venusian atmosphere might seem rather miniscule, relative to the 71% of Nitrogen here on the Earth. But, the amount of Nitrogen found on Venus far outweighs that of the Earth several times, once compared quantity-wise (that rhymes!). Quantity-wise, the Venusian atmosphere houses a staggering 3 bars of Nitrogen – which is about four-times larger than that found on the Earth!

To put that into perspective, the Venusian atmosphere has 3.5 Earth-atmospheres of Nitrogen. Having 3.5 atmospheres of Nitrogen would mean that, “even if the entire atmosphere was filled with cloud cities, with populations greater than the Earth, they would never run out of nitrogen for plants and for a buffer gas for breathing” ^[8]. As for Mars, some of us might not believe me saying that ‘extracting Nitrogen from the Martian near-vacuumish isn’t hard’. Well, this claim is profoundly in error, as the amount of atmospheric Nitrogen merely accounts for a meagre ~0.0004536 bars! The amount of Martian Nitrogen is literally a vacuum if it were rounded to the third decimal place! Extracting such a tiny quantity of Nitrogen from a vacuumto the first decimal place (the Martian atmosphere), is no trivial task – It’s in-between the margin of possible and impossible, and would require gargantuan and shrewd engineering to do so. Still, even if such a feat were to be achieved, it is quite questionable whether the sum of every single molecule of atmospheric Nitrogen, would be able to sustain a para-terraformed Martian civilization with populations greater than the Earth, or even Martian populations before that! A lot of Nitrogen would have to be imported from the Earth – or even Venus! – In order to fulfil the Martian demands of Nitrogen as a buffer gas.

Another perk for the Venusians for having a virtually never-ending source of Nitrogen, is the ability of creating more of the derived ions of Nitrogen – the Nitrites, Nitrates and Ammoniums – which are commonly used in the artificial fertilization of soil, which in-turn is fundamentally required for agricultural and Horticultural activities. It would also be helpful in maintaining the Nitrogen cycle on the cloud cities: the Venusian atmospheric Nitrogen, finds its way into the soil as the derived ions, and would eventually be recycled back into the Venusian atmosphere, and the cycle repeats.

There many helpful reasons for extraterrestrial colonies to have Nitrogen. Owing to that, because of (1) The Venusian atmosphere houses an incredible 3 bars of Nitrogen. (2) The Martian atmosphere houses a meagre 0.0004536 bars of Nitrogen. (3) The Venusians would never run-out of Nitrogen as a buffer gas or derived fertilizer, and (4) The Martians might run-out of Nitrogen as a buffer gas or derived fertilizer: We can conclude that The Venus has virtually unlimited Nitrogen, which makes the Venusian atmosphere more beneficial and better for  its colonization than the Martian surface.

8.        Walker, R. (2014, January 12). Will we build colonies that float over Venus like Buckminster Fuller’s “Cloud Nine?”  Retrieved from (https://www.science20.com/robert_inventor/will_we_build_colonies_that_float_over_venus_like_ buckminster_fullers_cloud_nine-127573).

15.        Wikipedia (at 2019, February). Retrieved from (https://en.m.wikipedia.org/wiki/Mars).

17.        Wikipedia (at 2019, February). Retrieved from (https://en.m.wikipedia.org/wiki/Venus).

49.        Wikipedia (at 2019, February).Retrieved from (https://en.m.wikipedia.org/wiki/oxygen_toxicity).

Achinthya Nanayakkara (31.03.2025)

Originally written - 2019