posted 12-22-98 07:03 PM ET        

First, what needs to be changed?

1. the nitrogen in the atmosphere will have to be filtered somehow

2. th atmospheric pressure will probably need to be lower so you dont get nitrogen narcousis("the bends") we you go back inside.
Chiron's pressure at sea-level is about 1.74 times Earth's pressure at sea-level. This was metioned in the report on Chiron a few weeks ago.

posted 12-24-98 02:16 AM ET            

I'd say that one would have to exploit the co2 from the fossil fuel deposits, and use terran plants to convert it to O2. Of course, massive domes would be needed for this approach, and it would take lifetimes.

posted 12-24-98 03:59 AM ET            

Mainly, you need to work methods of fixing the nitrogen into the soil. Since this isn't a completely dead world, we can genegineer some terran forms of lichen or even larger plants to thrive.

Possibly, since Chiron may be younger (read: lifeforms and vegetation may be less evolved than terran stock) and will not benefit from directed genengineering (Or maybe they will...) competition should be pretty neat twixt plants and stuff.

On mars, talk has been about slamming comets and chondrite asteroids into the planet to generate heat & water & biologicals. Hm, dunno if that would work, but... Worth a shot.

posted 01-04-99 05:27 PM ET            

Introduction - the astrophysical background

Alpha Centauri A ("Alpha Prime") is a G2V main sequence star, similar in spectral class to the Sun, but about a billion years older. Chiron (or "Planet" as most of the colonists refer to it) is a 1.8 Earth mass planet orbiting at 1.08 AU from Alpha Prime, receiving 23% more sunlight than Earth does at the present.

Like the Sun, Alpha Prime was once about 30%-40% dimmer than its present luminosity. Stars grow continually more luminous over their lifetime on the main sequence - this was a matter of some concern to astronomers in the past (Hart 1978) who reasoned that if the Sun had been much less luminous than it is today, then the Earth should have been locked in a permanent ice age. But the geological record shows that Earth was not significantly cooler than it is today. This was known as the Faint Young Sun Paradox.

It was Walker and Kasting who pointed out (1981) that if the Earth had had a much greater amount of CO2 in the atmosphere, then the CO2 greenhouse effect could account for the difference. CO2 is emitted into the atmosphere from volcanoes and weathered out of the atmosphere by the reaction CaSiO3 + CO2 ---> CaCO3 + SiO2 broken down into silicate rocks and CO2, and the cycle begins again. The crucial feature of this cycle is that the weathering reaction is temperature dependent: the higher the temperature, the faster CO2 is removed from the atmosphere. So the carbonate-silicate cycle acts as a planetary thermostat, keeping temperatures constant even while stars vary over geological time.

On Earth, the consequence was that life evolved in an atmosphere of up to 1000 millibars CO2 or even more. The first photosynthesising organisms using atmospheric CO2 may have evolved up to four billion years ago and have dominated the biosphere ever since. But on Chiron, the temperature was already too high to support a dense CO2 atmosphere, and carbon was a much less available element in the warm early seas. This has led to a very different evolutionary path.

Chiron today - atmospheric composition

The atmosphere consists of >160 kPa N2, <15 kPa O2 and <20 Pa CO2. The low oxygen content results in fewer forest fires, a higher proportion of anoxic environments - encouraging a large anaerobic ecosystem reducing nitrates to break down organic matter, about which more later (see report on "xenofungus") - and a plant ecosystem dominated by the need to conserve carbon.

Meteorology and Climatology

The warm tropical seas of Chiron are breeding grounds for hurricanes, which are also encouraged by the high gravity and rapid rotation. The dense nitrogen atmosphere only partly offsets this. The equatorial cloud belts, however, help to regulate the climate by reflecting sunlight.

Because the planet spins faster, the winds follow the lines of latitude more strictly than on Earth. Moreover, the meridional circulation splits into five cells, as opposed to Earth�s three (Hadley, Ferrel, and Rossby). Compare this to the bands on a giant, rapidly rotating planet like Jupiter or Saturn.

Oceanography

At over 20% higher insolation than Earth, Chiron has very small polar ice caps. The effect of this on the oceanic circulation is profound. Instead of cold oxygen-rich polar water sinking at the poles and being carried in a current along the ocean floor to the equator (as on Earth today), the circulation is driven in reverse, with warm saline oxygen-poor water sinking at the equator and flowing to the poles (as on Earth in the Cretaceous period). As a result, the bottom waters are highly anoxic (note: such seas are called euxinic after the Black Sea).

Soil Composition

Compared to Earth, silicates are much less common in the soils of Chiron. As in the tropics on Earth, warm water leaches the silica from clays, leaving a poor alumina-rich soil (this does not prevent rain forests from growing, but will inhibit agriculture). The arctic regions have a higher proportion of acidic soils with a high proportion of organic matter (podzols) which is equally hard to farm. The temperate soil zone, which on Earth is favoured with rich aluminosilicate clays, is much narrower here on Chiron, and the soils are more likely to be sandy or lime-rich. Bogs are also common.

Ecology

Although basically similar to Earth life, in that it is based on carbon compounds in water, the organisms of Chiron have evolved a biochemistry very different Earth. The scarcity of carbon in the environment, and of dioxygen in the soil, has forced plants to try to make do without O2, and economize on the use of carbon in structural parts and as an energy storage material. They do this by using a biochemical reaction unknown on Earth

N2 + H2O + 5/2O2 --> 2H+ + 2NO3- ( -7 kcal mol-1 )

as can be seen, this reaction is exothermic, but (thankfully) is unknown on Earth. Chironian plants seem to have a special enzyme to encourage this reaction, possibly with the aid of sunlight. They use the nitrate obtained this way to store energy as organic nitro-compounds (see report on "gun-cotton trees"); to reduce carbonates to carbon; and to carry out respiration in anoxic environments.

The prevalence of anoxic environments rich in organic material, combined with the presence everywhere on Chiron of nitrated compounds has led to an astonishing variety of underground organisms (see report on "xenofungus") which live in the absence of oxygen (though they can use oxygen if it is present) and "breathe" nitrate:

(CH2O) + NO3 ---> H2O + CO2 + 1/2N2O + 1/4O2

This ecosystem apparently has symbiotic relations with the plants and with Chironian animal life (see report on "mind worms"). The prevalence of nitrate in the environment has serious repercussions (see below).

The nitrous oxide is present in only small amounts as it combines with ozone in the stratosphere to break down into N2 and O2 light

N2O + O3 ---> 2NO + O2 ; 2NO ---> N2 + O2

This process prevents the build-up of an ozone layer.

When plant material is buried, nitro-hydrocarbons have all they need to "burn", so they will do so slowly underground, leaving nothing behind until all the reducing material (hydrocarbon) or all the oxidizing material (nitrate) has gone. We expect the nitrate to run out first in all cases, leaving a residue of carbon compounds. Provided this does not come into contact with oxygen, it will fossilize to produce ordinary fossil fuels. Since Chiron has been hot and hypoxic for a long time, it should have all the oil, shale, and coal the colonists could want.

This will be a focus of the colonists� terraforming efforts to increase the CO2 (and hence oxygen) as they transplant Earth vegetation to Chiron. They will also want to blast chalk limestone deposits (which are also abundant on Chiron) to liberate the CO2.

Regardless of any attempt to wipe out the underground nitrate respirers, all our efforts to return carbon to the biosphere will encourage Chironian life to proliferate. Conversely, the huge quantities of nitrate in the soil will be heaven to human farmers.

But the water will have to be treated in order to remove the nitrates so that it is safe to drink; otherwise the colonists may suffer from methaemoglobinaemia, or "blue baby syndrome", where the red blood cells are poisoned so they can�t take up oxygen. The way to do it is to pass ozone through the water to destroy the nitrate.

posted 07-08-99 07:53 PM ET         

Blowing it out with a PlanetBuster?

posted 07-09-99 11:51 AM ET         

Of all of us that have been penninf fiction about Chiron, I think you're the only one that's done the homework.

Planet.txt says:

Atmosphere

Total pressure Pa 101325 176020 1.74
Nitrogen Pa 79125 160000 2.02
Oxygen Pa 21228 15000 0.71
Argon Pa 942 1000 1.06
Carbon dioxide Pa 30 20 0.67

Nitrogen 78.09% 90.90% 1.16
Oxygen 20.95% 8.52% 0.41
Argon 0.93% 0.57% 0.61
Carbon dioxide 0.03% 0.01% 0.4

Surface density kg m-3 1.22 2.06 1.68
"Flammability" mmol K J-1 7.17 2.87 0.40

Effective temp. K 253 261 1.03
Greenhouse effect K +36 +32 0.90
Surface temp. K 288 293 1.01
Surface temp. C 15.4 19.7 1.28
Solar constant W m-2 1383 1750 1.27

If not openly hostile to humans, would certainly produce breathing problems without some oxygen supplement.

posted 07-09-99 11:53 AM ET         

Visit planet.txt to see it laid out for Earth/Chiron comparison

posted 07-09-99 04:04 PM ET         

Ah! you'd be okay with that oxygen, you only use about 7% of what you breathe in.
(hence why CPR works)

posted 07-09-99 04:55 PM ET         

Penning, that's what I was trying to say, penning, penning.

Ah well, it's still a slow day in the good ole Pacific Northwest, but at least the sun is shining now

posted 07-11-99 06:24 PM ET         

Does anybody have an idea for locking away the nitrogen?

Converting it into nitrates is going to saturate the eco-system, and remove oxygen, which is not wanted!

Converting it into some compound, involving carbon and oxygen (protein-esque) would involve GE and what to do with the plant matter?

I am stumped!

posted 07-11-99 06:32 PM ET         

Release CO2 by burning plant matter etc (this would make the natives go loco, but hey!).

It is quite difficult to engineer against the bends. Unless you want to become whale shaped.

You then form with the nitrogen
(Some energy source+catalyst)

2CO2+2N2----------------------> 2N2O+2C0

Very difficult to pull off, and you would need to bin the nitrous oxide.

posted 07-12-99 04:33 AM ET            

Eccles: what's the evidence for Chiron Nitrogen levels being on the margin of narcosis?

The partial pressure of nitrogen in lungs and blood vessels at an underwater depth of one foot (sic!) exceeds that of Chiron at sea level, doesn't it?

I don't recall getting the bends from shallow diving.

Sam(bo) Green: Re terraforming Mars, I'm _very_ sceptical. In those proposals, no consideration appears to have been given to the weak gravitation of Mars. There is a reason why the moon, with 1/6 Earth gravity, and the same solar distance, has negligible atmosphere (it takes very refined instruments to detect any), and why Mars, with about half our insolation and 1/3 our gravity, has a thin atmosphere (approximately 1 kPa, or 10 millibar in total pressure) composed mainly of the heavy gas CO2. My expectation is that if we could deposit all of the Earth's oxygen (O2) on Mars, it would migrate into space within a few weeks - due to oxygen's typical molecular velocities (at Mars temperatures) exceeding Mars's gravitational escape velocity.

This is also why Earth does not retain atmospheric Hydrogen (H2) and Helium (He); and it's just as well that we don't have a thick hydrogen atmosphere to contend with.

Water vapor (H2O) would disappear even more quickly from Mars than oxygen would. But Mars does have water, in the form of ice sheets. IMO that's the only form in which water can be retained. The evidence of streams may be due to temporary flows after cometary impacts; the water would subsequently have either become locked into ice, or evaporated off the planet.

In summary, Mars is too cold to have liquid water, and too hot (sic!) to retain gaseous oxygen or water vapour, given its weak gravity.

googlie: those figures you quoted are for Earth. What "breathing problems"? Unless you refer to inner city living.

posted 07-12-99 03:03 PM ET         

I agree that it would be silly to have my reduction reaction. However, the question was about terraforming, and that would be a way of getting rid of the damn nitrogen!

I don't think the gravity of Mars has as much effect as you expect. Mercury, same gravity as Mars, has less atmosphere. Titan, less gravity than Mars, has a thicker atmosphere. The disparities are more often to do with temperature (as you mention) and the original formation.

Remember Mar's original Oxygen combined with the Rocks.

I think that Hydrogen (Molar Mass=1)is the only substance that can escape earth orbit. (helium is questionable).
So Mars, having a third as much gravity, allows objects of 3 times that weight to escape.
Oxygen has a MM of 16. Water MM 18.
Mars would let Lithium escape. Considering that Mercury has a lithium atmosphere and simular gravity, that may be wrong.
In low pressure the water would either be gasous or solid. The water on Mars is probably in permafrost etc.
Any stuff that breaks out into the atmosphere will travel to the poles (I can't remember the name of the theory)

Terraforming Venus. I want to have a discussion about that. I think it impossible!

posted 08-03-99 03:05 PM ET         

As far as my knowledge goes, the partial pressure of Nitrogen on Chiron is not enough to cause Nitrogen narcosis. If you dive to a depth of 10 meters (on earth) using scuba gear, you will have a _higher_ partial pressure of this gas than on Chiron - and divers by far are not affected by any kind of narcosis at this depth. As far as I know, you can dive to depths of about 50 meters using compressed air only - and there the partial pressure of Nitrogen is about three times that of Chiron.

In fact, if you intend to go deeper, you would have to reduce the content of oxygen first - because oxygen gets toxic faster at higher partial pressures than nitrogen.

The use of a helium/oxygen mix is necessary if you intend to surface quickly, to prevent the nitrogen that is solved in your blood to form bubbles and block your blood vessels (like opening a bottle of soda). This is a physical effect, and has little to do with actual toxicity of nitrogen.

posted 09-08-99 10:04 AM ET            

"I came apon a revelation when I tried to catalog your species. I found out that you are actually not mammals. You see, mammals naturaly attain an equilibrium with their surrounding environments, but humanas do not. Humans consume all resources in their habitation until baren and then move on to the next, only to strip that completely as well. There is one species that displays this behaviour... a virus. And everytime I come near one of you I fear I might become infected..."