Would this Venus have a habitable atmosphere?

[fredinno]

This entry from the alternate solar system thread is problematic.

We need to see if the atmosphere is habitable- the temperatures are ok, so that's not a problem.

Would it be habitable? Or would you need an oxygen mask?

I also would like to ask if it would be habitable at Aphrodite Terra.

-Venus: (0.815x Earths Mass) A habitable planet orbiting at a high inclination in resonance with Earth (avoiding high gravitational interactions with it that would sling it out of its orbit.) It has a (somewhat thick) atmosphere, magnetic field and a surface much different from OTL. Despite being habitable for life, it is a very dry desert planet, and lacks animals, as there is not enough water to support the amount of plants needed by animal life (aside from its intelligent species, which we will get to later). The surface water available is concentrated in a few small oasises. The surface terrain is composed of flat plains, and high, volcanic plateaus- most of which merged into one large plateau near the equator where Aphrodite Terra is OTL (these form as Venus lacks the water for tectonic plates). The air has a 15% O2 content (with the rest mostly nitrogen), and the surface temperatures average 50-60° C (black body+GHG). (the surface pressure is 78% of Earth's) Aphrodite Terra contains high concentrations of Uranium-235 for nuclear weaponry, Gold, and Platinum-Group minerals for mining.

Venus is also one of three places outside Earth that has intelligent life, which is currently a small, feudal, agrarian society. This is strange, as the planet lacks animals. It is thought that these bipedal green animals were from another star system, before settling in Venus and losing their technology, and their society collapsed. The intelligent life here is very limited in number due to only having a few areas on Venus with enough water to support them. This also limits their technological advancement, though they love and greatly value the technology they DO see and/or obtain (much like the Manus islanders in OTL).

Oh yeah, and the first man to step foot here was Simon Wolf Edmunds, and thus the first base here was called Edmunds' Step. [0.9 G] PLANET (40°) {0.74 AU}

[Spaceception]

45 minutes ago, fredinno said:

IThis entry from the alternate solar system thread is problematic.

We need to see if the atmosphere is habitable- the temperatures are ok, so that's not a problem.

Would it be habitable? Or would you need an oxygen mask?

I also would like to ask if it would be habitable at Aphrodite Terra.

-Venus: (0.815x Earths Mass) A habitable planet orbiting at a high inclination in resonance with Earth (avoiding high gravitational interactions with it that would sling it out of its orbit.) It has a (somewhat thick) atmosphere, magnetic field and a surface much different from OTL. Despite being habitable for life, it is a very dry desert planet, and lacks animals, as there is not enough water to support the amount of plants needed by animal life (aside from its intelligent species, which we will get to later). The surface water available is concentrated in a few small oasises. The surface terrain is composed of flat plains, and high, volcanic plateaus- most of which merged into one large plateau near the equator where Aphrodite Terra is OTL (these form as Venus lacks the water for tectonic plates). The air has a 15% O2 content (with the rest mostly nitrogen), and the surface temperatures average 50-60° C (black body+GHG). (the surface pressure is 78% of Earth's) Aphrodite Terra contains high concentrations of Uranium-235 for nuclear weaponry, Gold, and Platinum-Group minerals for mining.

Venus is also one of three places outside Earth that has intelligent life, which is currently a small, feudal, agrarian society. This is strange, as the planet lacks animals. It is thought that these bipedal green animals were from another star system, before settling in Venus and losing their technology, and their society collapsed. The intelligent life here is very limited in number due to only having a few areas on Venus with enough water to support them. This also limits their technological advancement, though they love and greatly value the technology they DO see and/or obtain (much like the Manus islanders in OTL).

Oh yeah, and the first man to step foot here was Simon Wolf Edmunds, and thus the first base here was called Edmunds' Step. [0.9 G] PLANET (40°) {0.74 AU}

I don't think it'd be breathable, since there's not a lot of plant life that can produce large quantity's of Oxygen, people who know biology better can correct me, but I don't think it would have enough plant life to produce that much Oxygen, and the equator likely wouldn't be habitable due to the high temperatures, but the area near the poles would likely be close to habitable.

[fredinno]

16 minutes ago, Spaceception said:

I don't think it'd be breathable, since there's not a lot of plant life that can produce large quantity's of Oxygen, people who know biology better can correct me, but I don't think it would have enough plant life to produce that much Oxygen, and the equator likely wouldn't be habitable due to the high temperatures, but the area near the poles would likely be close to habitable.

Well, it wouldn't be habitable for humans due to the temperature without a temperature cooling suit, but those are very simple to get and make.

[Snark]

Matters of temperature aside, you really only need two things for the air to be breathable:  enough oxygen, and a lack of anything toxic (such as, for example, excessive CO2).

You haven't said anything about toxins, but if we assume that you're okay on that front, the question is whether you have enough oxygen.  15% O2 content with an atmosphere that has 78% of Earth sea level pressure means that the partial pressure of O2 will be about 55% of Earth's. A bit thin, but breathable. It's equivalent to being at an altitude of a bit under 5000m on Earth. I wouldn't want to try to run a footrace, but no breathing mask required.

[Windspren]

Those green things sound a lot like Kerbals...

[fredinno]

33 minutes ago, Laythe Dweller said:

Those green things sound a lot like Kerbals...

That was the plan. We might move them to another star system tho.

1 hour ago, Snark said:

Matters of temperature aside, you really only need two things for the air to be breathable:  enough oxygen, and a lack of anything toxic (such as, for example, excessive CO2).

You haven't said anything about toxins, but if we assume that you're okay on that front, the question is whether you have enough oxygen.  15% O2 content with an atmosphere that has 78% of Earth sea level pressure means that the partial pressure of O2 will be about 55% of Earth's. A bit thin, but breathable. It's equivalent to being at an altitude of a bit under 5000m on Earth. I wouldn't want to try to run a footrace, but no breathing mask required.

Ok, thank you.

[Andem]

Definitely should be breatheable, although any would-be explorers would have semi-serious issues if they came down too fast.

[ChrisSpace]

20 hours ago, Snark said:

Matters of temperature aside, you really only need two things for the air to be breathable:  enough oxygen, and a lack of anything toxic (such as, for example, excessive CO2).

You haven't said anything about toxins, but if we assume that you're okay on that front, the question is whether you have enough oxygen.  15% O2 content with an atmosphere that has 78% of Earth sea level pressure means that the partial pressure of O2 will be about 55% of Earth's. A bit thin, but breathable. It's equivalent to being at an altitude of a bit under 5000m on Earth. I wouldn't want to try to run a footrace, but no breathing mask required.

Okay, is suppose it could work that way, just barely.

[fredinno]

22 minutes ago, ChrisSpace said:

Okay, is suppose it could work that way, just barely.

But this would likely prevent intelligent animal life- we could move it to Luna or a Nibiru planet. Yes, they'd be adapted, but the amount of animal life needed for evolution to that point is higher than the amount of vegetation would permit.

[Findthepin1]

Humans can live perfectly fine at those oxygen levels. I think some countries have villages with comparable partial pressure of O2. Why wouldn't any comparable animal be fine on Venus? I don't see why not.

Edited March 12, 2016 by Findthepin1

[fredinno]

2 hours ago, Findthepin1 said:

Humans can live perfectly fine at those oxygen levels. I think some countries have villages with comparable partial pressure of O2. Why wouldn't any comparable animal be fine on Venus? I don't see why not.

Because the 15% oxygen level was an oxygen level calculated without lots of animal life.

This is a desert,there are too few plants to produce oxygen.

[Andem]

7 hours ago, fredinno said:

Because the 15% oxygen level was an oxygen level calculated without lots of animal life.

This is a desert,there are too few plants to produce oxygen.

So the issue is that intelligent life would have used all of the oxygen by the time it evolved enough to become intelligent?

What if high in the atmosphere algea would form (somehow) replacing toxins with oxygen?

[Snark]

9 hours ago, fredinno said:

Because the 15% oxygen level was an oxygen level calculated without lots of animal life.

This is a desert,there are too few plants to produce oxygen.

...so where did the oxygen come from?

And I would be surprised if the primary consumer of oxygen is animal life, particularly on a planet without a dense biosphere.  Oxygen is an extremely reactive chemical and will typically find something in the environment to combine with, given enough time.  You don't get a planet with an oxygen atmosphere without having a continuous supply of the stuff.

Also, if there aren't enough plants to produce breathable oxygen for animals, then there certainly won't be enough plants to feed them.  What are these animals going to eat?

In a typical biosphere (where by "typical" I mean "the lone example we know of"), the overwhelming majority of the biomass is plants; over 400 tons of plant life for every ton of animal life.  Bacteria run a close second, at around half the mass of the plants.

So unless you're postulating some science-fictional ecological gimmick:  if you want to know how much animal life there's going to be, take the mass of plant life and divide by 400 or so.

[Findthepin1]

10 hours ago, fredinno said:

Because the 15% oxygen level was an oxygen level calculated without lots of animal life.

This is a desert,there are too few plants to produce oxygen.

Venus needs a lot less oxygen. 

[fredinno]

17 minutes ago, Findthepin1 said:

Venus needs a lot less oxygen. 

why?

[Findthepin1]

1 hour ago, fredinno said:

why?

No plants to make it. If Venus has so little plants compared to Earth, it'd have correspondingly little oxygen. It's a thin-air desert, a drier version of the Altiplano. The plant biomass is like 1 to 10 percent the Earth average. That means it'd have 1 to 10 percent the oxygen partial pressure.

Say, for example, it's five percent plant biomass relative to Earth. It'd then have five percent the partial pressure of oxygen on Earth's surface. Earth's surface has 20 kpa. Venus, with five percent plant biomass, would have five percent that number, or 1 kpa of oxygen. It's worth noting that Venus only has significant biomass of any kind near the water, of which there is not a lot. So it'd likely have a quite small amount of oxygen, not enough for any large animal life (insects at the most).

What we need to do is either give Venus a lot more plants or a lot less animals. No intelligent civilizations there, unless they breathe CO2 or something.

[insert_name]

why not add atmospheric algae to increase o2

[fredinno]

48 minutes ago, insert_name said:

why not add atmospheric algae to increase o2

No such thing exists.

3 hours ago, Findthepin1 said:

No plants to make it. If Venus has so little plants compared to Earth, it'd have correspondingly little oxygen. It's a thin-air desert, a drier version of the Altiplano. The plant biomass is like 1 to 10 percent the Earth average. That means it'd have 1 to 10 percent the oxygen partial pressure.

Say, for example, it's five percent plant biomass relative to Earth. It'd then have five percent the partial pressure of oxygen on Earth's surface. Earth's surface has 20 kpa. Venus, with five percent plant biomass, would have five percent that number, or 1 kpa of oxygen. It's worth noting that Venus only has significant biomass of any kind near the water, of which there is not a lot. So it'd likely have a quite small amount of oxygen, not enough for any large animal life (insects at the most).

What we need to do is either give Venus a lot more plants or a lot less animals. No intelligent civilizations there, unless they breathe CO2 or something.

Well, I originally made the calculations based on this:https://en.wikipedia.org/wiki/Oxygen_cycle

Photosynthesis (land) Photosynthesis (ocean) Photolysis of N2O Photolysis of H2O	16,500 13,500 1.3 0.03
Total gains	~ 30,000
Losses - respiration and decay
Aerobic respiration Microbial oxidation Combustion of fossil fuel (anthropogenic) Photochemical oxidation Fixation of N2 by lightning Fixation of N2 by industry (anthropogenic) Oxidation of volcanic gases	23,000 5,100 1,200 600 12 10 5
Losses - weathering
Chemical weathering Surface reaction of O3	50 12
Total losses	~ 30,000

[Andem]

If not in the atmospher why mot an extremely potent algea in the water?

[Findthepin1]

48 minutes ago, fredinno said:

No such thing exists.

Well, I originally made the calculations based on this:https://en.wikipedia.org/wiki/Oxygen_cycle

Photosynthesis (land) Photosynthesis (ocean) Photolysis of N2O Photolysis of H2O	16,500 13,500 1.3 0.03
Total gains	~ 30,000
Losses - respiration and decay
Aerobic respiration Microbial oxidation Combustion of fossil fuel (anthropogenic) Photochemical oxidation Fixation of N2 by lightning Fixation of N2 by industry (anthropogenic) Oxidation of volcanic gases	23,000 5,100 1,200 600 12 10 5
Losses - weathering
Chemical weathering Surface reaction of O3	50 12
Total losses	~ 30,000

The variables are going to be different on Venus.

First and foremost, photosynthesis will be a lot lower. Venus is a desert. There's barely any plant life in deserts. So there will be barely any oxygen. Nitrogen fixation by lightning will probably be lower (little water means few clouds to create lightning) and that by industry is going to be very nearly zero). By the way, this does mean there should be more nitrogen. Oxidation of volcanic gases will also likely be lower because Venus would have less volcanism (Earthlike planet with Earthlike surface temperature means surface geology would be much more similar to Earth's, but drier, so less or no plate tectonics, which means a thicker crust, which means less volcanoes). Zero combustion of fossil fuels by anything because Venus wouldn't have any accessible fossil fuels as a desert. The only areas with significant fossil fuels would be the seafloor, a fact which no Terran civilization would know about and no Venusian civilization would need. And more differences besides.

The more I think about it, the more I expect a habitable desert Venus isn't doable. Assuming we can't do that, what would be the alternatives?

Edited March 12, 2016 by Findthepin1

[fredinno]

Image analysis of Venus Topography map above shows:

Spoiler

Let's just say all the blues (excluding turquoise) is water, which would leave ~22.5% of the surface, water. The equilateral regions have 5% less water area, increasing the chances of habitability.

https://en.wikipedia.org/wiki/Venus

http://www.projectrho.com/public_html/rocket/basicdesign.php#id--Power_Generation

Solar intensity is 2635 W/ m2, or 151% Earth solar light intensity, assuming no clouds. This is enough to allow water at the equator, which should evaporate in the hottest of summer days, then precipitate back at night, as the average equilateral temperature is 82C, and average polar temperature is 38C.

The effect on this on plant growth is varied, and is a subject all by itself. It increases for Earth plants to a point, before dropping off again, and every plant species is different. However, most plants only grow more from more sunlight up to 100W/m2, on Earth, about 10% of light. This is fine, as the lower leaves are shielded from the Sun, so are more efficient, but also puts limits to how much more effective our Venus plants can be. Assuming they also use 10% of light, evolving in a similar way to our plants, but with more sunlight, they'd produce 172% the oxygen.

https://en.wikipedia.org/wiki/Photosynthetic_efficiency#Plants

If land plants cover 10% of the land, and each produces 172% of the oxygen, the 'land' photosynthesis number is at 2322.

Doing the same thing for ocean plants, brings a 4644 number for ocean O2 production. However, shallow oceans are more biologically productive, so we'll increase that to 6500.

https://ca.answers.yahoo.com/question/index?qid=20140318094132AADppEV

Plants absorb 10% of their own CO2 produced to survive, so reduce the production numbers by 10%. Thus, plants will produce 10030 units of O2. Removing all non- animal O2 consumption leaves 4251 units of O2. That would be enough for a relatively small amount of small animals as apex predators (like mice) and insects, and leave the 15% O2 rate, in my opinion (of course this is an educated guess). What do you think?

16 minutes ago, Findthepin1 said:

The variables are going to be different on Venus.

First and foremost, photosynthesis will be a lot lower. Venus is a desert. There's barely any plant life in deserts. So there will be barely any oxygen. Nitrogen fixation by lightning will probably be lower (little water means few clouds to create lightning) and that by industry is going to be very nearly zero). By the way, this does mean there should be more nitrogen. Oxidation of volcanic gases will also likely be lower because Venus would have less volcanism (Earthlike planet with Earthlike surface temperature means surface geology would be much more similar to Earth's, but drier, so less or no plate tectonics, which means a thicker crust, which means less volcanoes). Zero combustion of fossil fuels by anything because Venus wouldn't have any accessible fossil fuels as a desert. The only areas with significant fossil fuels would be the seafloor, a fact which no Terran civilization would know about and no Venusian civilization would need. And more differences besides.

The more I think about it, the more I expect a habitable desert Venus isn't doable. Assuming we can't do that, what would be the alternatives?

Wait. I was accounting for that stuff, the post is above .

Higher sunlight also means more water evaporation, thus, I'm keeping the nitrogen fixation the same.

Venus still has a lot of volcanism, like Earth, due to its large size. It matters little on the grand scheme of things anyways.

 

A habitable desert is doable, just not how ChrisSpace likes it. It's going to be like the Luna size thing where he's just going to have to bite his lips and deal with reality. Desert planets are the only way Venus can have life, barring exotic biology.

1 hour ago, Andem said:

If not in the atmospher why mot an extremely potent algea in the water?

The algae would already be more potent due to the increased sunlight, along with plants in general, but is going to still be limited by CO2 production, which is going to be more limited.

Edited March 13, 2016 by fredinno

[insert_name]

wait, most of the earths O2 comes from algae in the sea I thought, it sounds like you want an ocean on this venus as well, so just add algae to that ocean

Edited March 13, 2016 by insert_name

[Findthepin1]

39 minutes ago, insert_name said:

wait, most of the earths O2 comes from algae in the sea I thought, it sounds like you want an ocean on this venus as well, so just add algae to that ocean

There is algae in that ocean. It's just not doing much. I don't know why. It should be doing as much as Earth. 

[fredinno]

17 minutes ago, Findthepin1 said:

There is algae in that ocean. It's just not doing much. I don't know why. It should be doing as much as Earth. 

It is doing much, in fact, it's going most of the O2 producing work.

Look back at my calculations.