# Possible effects of a dense argon atmosphere



## SnailsAttack (Oct 27, 2017)

In the book I am writing, I plan to have the protagonists go to a planet with a dense atmosphere of argon. The life forms on this planet would be primarily bioluminescent, using epidermal organs to create electric charges, which I presume would cause a bluish glow, the way that argon signs work when they're electrified.

I have a lot of questions on the feasibility of a planet like this, though, so I'd appreciate it if someone could help with answering the following questions.

1. How dense and pure would an atmosphere of argon have to be to have flora and fauna that can generate a glow using electricity?

2. How much energy would need to be exerted to create said glow? Would it be infeasible to have bioluminescent creatures under the atmospheric conditions required?

3. Could humans survive the atmosphere through acclimation to the density and an oxygen mask, or would a special suit that covers the body's various orifices do the job? Would they instead need a full body space suit or pressure suit?

4. Could the water be filled with bioluminescent bacteria that produce light in the same way as mentioned in question 2?

I'm not sure how argon lamps work or how the human body reacts under high pressures, so this might all just be stupid.

Regardless, thanks for reading. If you have an answer to any of these questions I'd very much like to hear them. Hopefully an ecosystem like this could be possible under certain atmospheric conditions, else I'll have to come up with a different idea. (god forbid haha)


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## Venusian Broon (Oct 27, 2017)

I'm just jotting down initial thoughts - so don't take anything I say as sacrosanct!

First - it does depend how hard SF you want to be. If not really much at all, just _make _up answers to your questions. 

But second, if you are looking at more 'grounded hard SF' - if the atmosphere is just Argon, how do your life forms generate energy to live? Argon is inert chemically so nothing should be able to use that. If you don't have oxygen which all plants and animals use to 'burn' and generate energy here on earth then I presume you have some other source?



SnailsAttack said:


> 1. How dense and pure would an atmosphere of argon have to be to have flora and fauna that can generate a glow using electricity?



Depends. A close to vacuum amount is required to create the familiar 'neon' signs. If it is closer to something like our sort of atmospheric pressure or more then you will probably get something like a Metal-halide lamp. i.e. Bright white. So I'm not sure a thick atmosphere of argon will give you a lovely purple visage, but probably white (?)

So to answer you, I'd guess any density would be fine. As for purity, a lot of modern lights use mixtures, so I would presume that impurities would be fine and may even cause noticeable differences (Colours, intensities?) 




SnailsAttack said:


> 2. How much energy would need to be exerted to create said glow? Would it be infeasible to have bioluminescent creatures under the atmospheric conditions required?



You could look up electrical ratings for Metal-halide lamps or gas discharging lamps to give you a ball park figure: Metal-halide lamp - Wikipedia, or Gas-discharge lamp - Wikipedia. However I presume that it will be related to the volume that will be lit up. So a small 'light' would require less energy. (Note that to make this light it has to generate temperatures of 1000-3000K, so it's pretty energetic.) 



SnailsAttack said:


> 3. Could humans survive the atmosphere through acclimation to the density and an oxygen mask, or would a special suit that covers the body's various orifices do the job? Would they instead need a full body space suit or pressure suit?



Depends entirely on what pressure you want. As I said before Argon is inert, so if it was at 1 Atm. pressure then a human would probably just need oxygen. With lower pressure, I think the biggest problem is drying out - the boiling point of water will decrease with pressure, and your ears - you will be constantly keeping high pressure inside via breathing. I'd probably want a helmet of some sort. The rest of the body might be fine! With high pressure, it's survivable _but _you have to acclimatise to it - think of deep sea divers who have to increase air pressure the deeper they go. By doing this, this causes nitrogen to dissolve in the blood and if not taken care of can result in Nitrogen narcosis. However you could use a oxygen/helium mixture instead: see Breathing gas - Wikipedia and the bit about helium.

(Note that it states in that article that argon is _more _narcotic than nitrogen so you should not be using that as a mixture with oxygen if the atmospheric pressure is greater than 1!)



SnailsAttack said:


> 4. Could the water be filled with bioluminescent bacteria that produce light in the same way as mentioned in question 2?



I'm not sure. You seem to be constructing a world that uses electrical discharge or voltage differences to make light. In a briny watery environment (like a sea!) such a method may be not feasible (unless of course the animals or plants made 'tubes' like fluorescent tubes that were separated from the water?) . Bioluminescence on Earth is all due to chemical reactions not electrical reactions.

Hope the above helps!


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## SnailsAttack (Oct 27, 2017)

@Venusian Broon Thanks for all the info! It seems like having creatures that take advantage of some kinda organic metal halide lamp would be a bad idea, as those lamps produce white light and require a substantial amount of power. 

However, mercury vapor lamps are almost as efficient as halide lamps and will produce bluer tones of light if an ever lower amount of energy is supplied (i think). However, mercury has a boiling point of around 600 degrees, so I'm not sure if the lamps themselves are actually going to have to get that hot to function?

I could reduce the air pressure, as the mercury vapor lamps will function under only one atmosphere, but then the water might boil away and the Mercury would probably still need more heat to stay as a gas and I'm not sure a planet like that could support life.

Like you said though, perhaps the plants and animals could form their own low-pressure high-temperature bulbs and absorb Mercury from other various sources.

Water-based bioluminescent bacteria or whatever probably wouldn't end up making too much sense for a variety of reasons, so I think I'll scrap that idea.

As of right now the sci-fi-ness isn't too grounded, but it's fairly realistic. I'd like to be scientifically accurate in most areas without sacrificing too much of the aesthetic value.

The atmosphere conditions are still up in the air I guess. (haha)

Anyways, thanks. I hope you can answer some of the disorganized questions I mentioned above.


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## chrispenycate (Oct 27, 2017)

When I was doing lasers I think they were argon - they were green ones (with a couple of odd low power lines in the reds). 
But the principal problem I see would be the voltage. Once the gas is glowing, you only need a hundred volts or so to keep it conducting, but the initial pulse to ionise whichever gas you choose is several thousand volts (and the tube was water cooled - you could consider lighting it up to be an exciting experience) Even mercury vapour uses the starter and choke in the fluorescent fitting to generate a short, very intense peak, which is later damped out by the conductivity of the ionised metal. But bioelectricity - from rays and electric eels and such - is generally not much higher than a hundred volts, even in fresh-water species - enough to keep a tube illuminated, once it had been triggered (perhaps) but not enough to start it glowing without a thunderstorm.

However, bioluminescent organisms succeed in producing enough light to read by (large print) entirely chemically, with no use of electricity. Bacteria, fungi, fireflies, glow-worms, some deep fish… though there is nothing that floats in the air and glows (plenty of glowy jellyfish if you want to live in water) but I can't see any particular reason not to create some.


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## DelActivisto (Oct 27, 2017)

I would just go with bioluminescence. This is done chemically, which for living organisms uses much less energy than supply direct electrical currents to something. It's an interesting idea to have creatures that make their own electricity, but I feel like as Hard Science as you're going, you want to explain it through evolution. For the most part, two major things drive evolution - survival and reproduction. If it helps a species survive, it tends to stay with the creature. If it helps the creature reproduce, it tends to stay with the species. So maybe this atmosphere is very dense and the creatures use the light to signal to each other, or maybe it signals sexual prowess, or something.


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## SnailsAttack (Oct 27, 2017)

DelActivisto said:


> So maybe this atmosphere is very dense and the creatures use the light to signal to each other, or maybe it signals sexual prowess, or something.


Yeah, I was gonna say that they communicated with each other using light, for example bioluminescent plants that attract insects to pollinate them, or animals that imitate the same light colors and shapes as said plants to hide from predators while remaining visible to other members of their species.


chrispenycate said:


> However, bioluminescent organisms succeed in producing enough light to read by (large print) entirely chemically, with no use of electricity. Bacteria, fungi, fireflies, glow-worms, some deep fish… though there is nothing that floats in the air and glows (plenty of glowy jellyfish if you want to live in water) but I can't see any particular reason not to create some.


Maybe it would just be easier to have creatures that use bioluminescence instead of biofluorescence. Is that a word I can use?

Anyways, I've done a bit more research on some various gas lamps and I believe that, without using the excuse of "well they're aliens so anything is possible", I could say that it's possible for creatures on a planet with an argon/oxygen atmosphere and mercury-rich soil to develop biological mercury-vapor lamps. They could start them up using a special electricity-generating organ combined with biological batteries, and only keep them on for as long as they need to, since they could theoretically be turned on and off at will (with the cost of a large amount of electricity on each startup, but probably not too much if the lamps are small and the lights are fairly dim).

Or maybe it just won't work out because of the requirements for ionizing the gas, keeping the lamp at a sweltering 357%, and then keeping the lamp active for a significant amount of time. I don't know. The science behind it is pretty interesting regardless. It's certainly a fun idea, if a bit infeasible.


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## DelActivisto (Oct 28, 2017)

I have an idea for a species that evolved nuclear energy capabilities in order to travel space without machinery. That's even more far fetched. 

Bioluminescence refers just to light that has a biological origin. Bioflourescence I don't think is a word, but would refer to light from a fluorescent origin.


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## Mirannan (Oct 28, 2017)

Discharge lamps of any sort have low-pressure gas inside - about an hundredth of an atmosphere, I think. This also applies to mercury lamps, although with them one has to vaporise the mercury first; I believe they usually have a heating circuit for use at switch-on. (The same applies to sodium lamps, but those would be even less attractive for something biological!)

I'd go with bioluminescence, although perhaps some sort of direct electricity to light conversion would work - an organic LED, maybe. (Perhaps organic OLED; the "o" in OLED means organic although organic doesn't mean the same to chemists as to foodies.  )

Regarding the effects of a dense argon atmosphere; yup, argon is more narcotic than nitrogen. Apparently, it has to do with molecular weight, with inert molecules actually dissolving into the nerve cell membranes. It's notable that the heaviest stable noble gas, xenon, is actually used on occasion as an anaesthetic. (Not used much, because it's horribly expensive.)

However, the effects of argon on Earthly life aren't really the point here IMHO. Why? Because the local life-forms would have been adapted to high argon levels from the start. Of course, visiting humans might have a problem without something rather like a diving hardsuit.


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## chrispenycate (Oct 29, 2017)

Fluorescence is the phenomenon of an atom (or maybe a molecule at long wavelengths, though I can't think of any examples off hand) absorbing radiant energy at one frequency (colour, wavelength) and reradiating at a lower frequency (longer wavelength, lower energy content). So it differs from reflection (where only the original frequencies are present, if in a different balance) and refraction. Thus, a mercury vapour lamp produces large quantities of short wavelengths, blue and ultraviolet, while a fluorescent tube shifts the higher frequencies down into the comfortable 'warm whites' and such less wearying for the eyes, much as a 'da-glo' emergency jacket does with solar radiation..

Bioluminescence is quite a common phenomenon - should you go out into the desert with a black-light (ultraviolet, as used by forensic detectives to identify blood - at least on the TV) you will discover scorpions and several species of bugs fluoresce, in different colours. A number of flower petals, too, have fluorescent markings to help insects (whose eyes tend to work up to higher frequencies than ours) get on with their pollination work. However, none of this involves generation of light, it is merely transformation.

I'll get my coat, shall I?


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## Mike Donoghue (Oct 31, 2017)

I saw it asked what the voltage would be in this proposed argon dense atmosphere that would result in fluorescence, and how much energy it would take to maintain. The answer lies in the phenomenon of "corona discharge". Wikipedia has a good overview of the process, found by searching "corona discharge".
In short, when the air particles near a high voltage source are ionized by some outside mechanism (an alpha particle from the decay of Radon, for instance), the ions and free electrons are accelerated by the electric field, which proceed to impact other air particles at high speed, causing them to be ionized, and so on and so forth until you have an "avalanche" of electrons and ionized particles. The light is generated by the electrons reattaching to the ions and the subsequent photons emitted as they drop energy levels.

You actually don't need an atmosphere full of argon to have a colorful corona discharge; it can happen in any gas of any composition, including our atmosphere.

What counts as a "high voltage source"? I am not quite sure, although keep in mind that high voltage AC transmission lines run in the tens to hundreds of kiloVolt range, but qualitatively speaking, sharp points and edges create higher electric field strengths because they act to concentrate electrons, versus spreading them out evenly (say on the skin of one of your animals). Your animals, therefore, could be spiky, or have hair-like filaments in order to glow. Electric eels are able to generate momentary voltages of over 800 Volts for fractions of a second. I believe these are generated in series, so to get higher voltages for longer periods you might need animals much bigger than electric eels.

In terms of energy consumption, you might be able to assume that the total energy efficiency and luminous efficacy of your animal in creating light via corona discharge are the same as a filament light bulb, since these lights generate light via temperature, so there is a lot of wasted energy in the form of heat, which might be reasonable since animals are not the most efficient. Your animal will have to constantly maintain that high voltage in order to accelerate those charged particles and create light, hence it will need to maintain a certain amount of power.

To picture this, if you want an animal to generate as much corona discharge light as a 7 inch plasma globe like you see at the mall, it will need to produce 1 Watt of light power, hence 20 Watts of its own power will be consumed for that light.

I hope this helps. This is a fairly complex subject, but it _does have answers_. It may or may not be above you to get _specific_ _scientifically precise _answers, but there's no shame in such back-of-the-envelope calculations.


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