Planets with Argon Atmospheres

[Wes]

I'm trying to get more information on what it'd be like on planets where most of the atoms in the atmosphere are Argon rather than Nitrogen.

Stuff we know:

• Argon is about 2.85 times heavier than Nitrogen.
• Argon molecules are single while Nitrogen usually is found in molecular pairs (N2).
• Argon can be formed by interactions involving radiation
• Its density causes it to hug the ground more
• Argon is more narcotic than Nitrogen

The question is how would this affect planetary life?

I found this thread helpful: http://flare.solareclipse.net/cgi2/ulti ... 002233;p=2 but I'm trying to find better sources of information.

 

[Yoshi]

not sure how it would affect planetary life, but lightning would be amazing. Argon lights are pretty cool looking, so I could only imagine if it was energized with a bolt of lightning.

on top of that Argon being denser would allow for sound to travel farther. any life on that planet would have kind of crappy hearing on other nitrogen based atmos.

 

[Aendri]

It would be remarkably unsafe for most traditional lifeforms as well. The fact that Argon is a noble gas makes it bad for the rest of the atmosphere from our perspective. Less natural bonding to retain oxygen and the like. It would also most likely have a higher gravity and lower visibility then normal planets.

 

[Wes]

Somewhat related:

We could really use some help finishing this Guide to Planet Types if anyone is interested.

 

[Floodwaters]

I remember asking a similar question regarding a planet's atmosphere a while back, and one of the things I'd read about argon (and other similar noble gasses) was, as you stated above, that it's heavier than Earth air and tends to sink. That said, in a human respiratory system, it would have a tendency to collect in the lungs since our diaphragm is used to expelling lighter gasses.

Even if the rest of the atmosphere isn't poisonous, breathing an atmosphere that is comprised mostly of argon (like our own atmosphere is comprised mostly of nitrogen) would eventually cause asphyxiation as more and more argon collects in the air sacs, displacing the lighter vital gasses we need to survive. Don't quote me, I'm not a scientist, but that's the conclusion I drew from what I found.

 

[BionicSamurai]

Somewhat related:

We could really use some help finishing this Guide to Planet Types if anyone is interested.

Damn, if only I saw this earlier. At a quick glance it looks like a nice start. I don't have a degree in Astrophysics, but planet compositions and such have been a huge part of my reading in Astronomy since I was five.

I remember asking a similar question regarding a planet's atmosphere a while back, and one of the things I'd read about argon (and other similar noble gasses) was, as you stated above, that it's heavier than Earth air and tends to sink. That said, in a human respiratory system, it would have a tendency to collect in the lungs since our diaphragm is used to expelling lighter gasses.

Even if the rest of the atmosphere isn't poisonous, breathing an atmosphere that is comprised mostly of argon (like our own atmosphere is comprised mostly of nitrogen) would eventually cause asphyxiation as more and more argon collects in the air sacs, displacing the lighter vital gasses we need to survive. Don't quote me, I'm not a scientist, but that's the conclusion I drew from what I found.

N2 has a molecular weight of about 28 and O2 is around 32, while Ar is around 40, lending to the plausibility. The ability of heavy gases to displace oxygen is one of the reasons why when the coolant pipes on your fridge rub through or a halon suppression system goes off, you want to be up hill and in an open environment.

Edit: forgot to include the weight of molecular oxygen. Once it hit my brain it wouldn't let me sleep. I think I may have only given a partial answer too... I really should do this when I'm more lucid.

 

[Legix]

So I figured I'd chime in here, primarily because I looked into making the Brolt breathe Argon. It was a lot of in-and-out looking around and there's a reason why I ended up going with Nitrogen instead (which is a more common alternative than oxygen).

In particular, it has to do with the science behind Argon lacking the same level of reactions that Oxygen and Nitrogen provide. I'm not a super science wizard, but it should be made clear that oxygen and nitrogen work out so well because they can be combined and utilized in coordination with various other elements to cause reactions that tend to generate energy. This is sorta the reason as to how oxygen and nitrogen are viable. Argon, however, has far less reactionary components.

As a result, the way I figured it was that most lifeforms from an argon planet would likely have two traits (which is why I didn't utilize it for the Brolt in their initial stages)

1. They would likely not be very active or would be more primitive creatures. This isn't to say they couldn't exist in a space empire as a citizen, but it would likely require them to be found and elevated with technology as an aid to provide them the intelligence level necessary to properly flow within space. A lack of energy means their body has to run on less... which likely leads to a brain that is focused on essentials like memory (which allow them to learn things to combat their inability to run with ideas and innovate).
2. If they were intelligent, they would likely be fairly small. A smaller body would grant them the ability to focus more on intelligence. These creatures would also rely on tools... so maybe an argon-breathing species could be rather small but utilize machinery bodies (like mecha). The chance of this evolution, though, is hindered by size and partially the same reason why there are fairly intelligent species around our size... but there's not as many close contenders at smaller sizes.