Inhabitable Planets Too Close Together?

I would guess all kind of Carbon in the planetary crust.

Weird Harold wrote:

namelessfly wrote:Based on allowable limits here:

http://ntrs.nasa.gov/archive/nasa/casi. ... 029352.pdf

All I'm getting from that link is a blank.

namelessfly wrote:Terraformers might leave enough CO2 to form a 1% atmosphere at STP which would provide an adequate CO2 reservoir.

Alternatively; you might draw down CO2 to 10% and allow plants to sequester most of it.

My concern was that in a pre-biota system, what other carbon is there (in any significant quantity) besides CO2, CO and possibly Methane?

1% CO2/CO might be a good value to have if the are significant carbon reserves already sequestered, but even 10% atmosphere might not be enough if there is no existing carbon sink.

http://en.wikipedia.org/wiki/File:Eleme ... dances.svg

I don't have lots of answers, but we have lots of Carbon.

It is one of the most common elements in Earth's crust.

namelessfly wrote:I would guess all kind of Carbon in the planetary crust.

Possibly, but in what form? AFAIK, most useable carbon in earth''s crust is organic. Would that carbon be there pre-biota?

Weird Harold wrote:

namelessfly wrote:I would guess all kind of Carbon in the planetary crust.

Possibly, but in what form? AFAIK, most useable carbon in earth''s crust is organic. Would that carbon be there pre-biota?

I haven't looked at the numbers, but I suspect Namelessfly is right. There is far more carbon available than is strictly necessary for biological life. Even if the atmosphere was stripped, there would probably be plenty for life. If any more were needed for the long term, it could be supplied from comets easily. There would be no rush for it. There would be plenty for life to get initially established, and it would take a very long time before fresh supplies of carbon were needed.

namelessfly wrote:The difficulty of eliminating reducing agents such as free Iron in the biosphere that would react with free Oxygen is perhaps overestimated. The reaction rate between Iron and Oxygen at room temperature is rather low and only free iron close to the surface would be able to react with atmospheric Oxygen. The only problematic Oxygen sink would be dissolved free Iron in planetary Oceans.

Based on this reference here:

http://www.jstor.org/discover/10.2307/4 ... 4098169283

The solubility of free iron in water is quite low. This is especially true if dissolved CO2 in the oceans is mi imized by stripping off a CO2 atmosphere prior to establishing an Oxygen atmosphere. Once the initial inventory of dissolved Iron is Oxidized, the limiting factor would be the rate at which new Iron is eroded and dissolved. Well tended biological processes would
probably do the job of maintaining the Oxygen supply but augmenting with continued industrial
processes might be needed.

Namelessfly is right, here. Under normal temperatures and pressures, oxygen sinks will not work fast enough to prevent a sufficient oxygen atmosphere from being produced.

Now, if you raise the temperature to several thousand degrees, the reaction rates will go sky-high. You would have a problem with oxygen sinks then. If you raise the temperature high enough, you will actually get oxides breaking down (as Namelessfly suggested with CO2). But when that atmosphere starts cooling off, it will rapidly combine with any available elements. And if you are doing this to the entire atmosphere, you can't really segregate the surface from the gasses.

But if your terraforming process doesn't require really high atmospheric temperatures, you should not have a problem with oxygen sinks, on the timescales of human civilization.

The more I contemplate the problem, the less I likely own idea of merely cooking the planetary atmosphere.

It occurs to that orbiting solar collectors could be teamed up with, near satellites at perhaps 50km altitude that have down sized magnetic ram fields perhaps 10 km in diameter that collect and compress upper atmospheric gases where they can be heated in an absorption chamber by the orbiting solar collectors. The net result is a ram augmented solar rocket that uses the planetary atmosphere as reaction mass that is then boosted beyond escape velocity. If drag counterbalanced thrust, it could function quite well.

Assuming a cruise velocity of perhaps Mach 10 and a throat area of perhaps one hundred meters and an atmospheric density at the throat of perhaps ten Kilograms per cubic meter, then the mass flow rate would be about ten tons per second or about 3eex8 tons per year.

I will have to go check the references on atmospheric mass.

SWM wrote:

namelessfly wrote:The difficulty of eliminating reducing agents such as free Iron in the biosphere that would react with free Oxygen is perhaps overestimated. The reaction rate between Iron and Oxygen at room temperature is rather low and only free iron close to the surface would be able to react with atmospheric Oxygen. The only problematic Oxygen sink would be dissolved free Iron in planetary Oceans.

Based on this reference here:

http://www.jstor.org/discover/10.2307/4 ... 4098169283

The solubility of free iron in water is quite low. This is especially true if dissolved CO2 in the oceans is mi imized by stripping off a CO2 atmosphere prior to establishing an Oxygen atmosphere. Once the initial inventory of dissolved Iron is Oxidized, the limiting factor would be the rate at which new Iron is eroded and dissolved. Well tended biological processes would
probably do the job of maintaining the Oxygen supply but augmenting with continued industrial
processes might be needed.

Namelessfly is right, here. Under normal temperatures and pressures, oxygen sinks will not work fast enough to prevent a sufficient oxygen atmosphere from being produced.

Now, if you raise the temperature to several thousand degrees, the reaction rates will go sky-high. You would have a problem with oxygen sinks then. If you raise the temperature high enough, you will actually get oxides breaking down (as Namelessfly suggested with CO2). But when that atmosphere starts cooling off, it will rapidly combine with any available elements. And if you are doing this to the entire atmosphere, you can't really segregate the surface from the gasses.

But if your terraforming process doesn't require really high atmospheric temperatures, you should not have a problem with oxygen sinks, on the timescales of human civilization.

Mass of the atmosphere is 5e18 kilograms or 5eex15 tons.

At 3eex8 tons per ram unit per year it will take a lot of years or a lot of ram units.

The idea still needs more work.

Back to heating the gross atmosphere using dust ejected by nuclear explosives or KE projectiles to act as a light absorber.

I prefer to use nuclear explosives because it is politically incorrect.

namelessfly wrote:The difficulty of eliminating reducing agents such as free Iron in the biosphere that would react with free Oxygen is perhaps overestimated. The reaction rate between Iron and Oxygen at room temperature is rather low and only free iron close to the surface would be able to react with atmospheric Oxygen. The only problematic Oxygen sink would be dissolved free Iron in planetary Oceans.

Based on this reference here:

http://www.jstor.org/discover/10.2307/4 ... 4098169283

The solubility of free iron in water is quite low. This is especially true if dissolved CO2 in the oceans is mi imized by stripping off a CO2 atmosphere prior to establishing an Oxygen atmosphere. Once the initial inventory of dissolved Iron is Oxidized, the limiting factor would be the rate at which new Iron is eroded and dissolved. Well tended biological processes would
probably do the job of maintaining the Oxygen supply but augmenting with continued industrial
processes might be needed.

Ummm.... Most iron is not found in reduced form, but as Fe(2) oxide, which is water soluble, add oxygen (or in the case of acid mine drainage raise pH) and it will convert to Fe(3) oxide which is water insoluble giving you banded iron ore and the distinctive orange tint of acid mine drainage.

Exactly.

However; the limiting factor is the amount of Fe-II dissolved in the oceans. Given the low solubility of Fe-II, it should not betokened difficult to provide enough Oxygen to precipitate it out. You would need to provide enough free Oxygen to compensate for more Fe-II being eroded and washed into the oceans.

Castenea wrote:

namelessfly wrote:The difficulty of eliminating reducing agents such as free Iron in the biosphere that would react with free Oxygen is perhaps overestimated. The reaction rate between Iron and Oxygen at room temperature is rather low and only free iron close to the surface would be able to react with atmospheric Oxygen. The only problematic Oxygen sink would be dissolved free Iron in planetary Oceans.

Based on this reference here:

http://www.jstor.org/discover/10.2307/4 ... 4098169283

The solubility of free iron in water is quite low. This is especially true if dissolved CO2 in the oceans is mi imized by stripping off a CO2 atmosphere prior to establishing an Oxygen atmosphere. Once the initial inventory of dissolved Iron is Oxidized, the limiting factor would be the rate at which new Iron is eroded and dissolved. Well tended biological processes would
probably do the job of maintaining the Oxygen supply but augmenting with continued industrial
processes might be needed.

Ummm.... Most iron is not found in reduced form, but as Fe(2) oxide, which is water soluble, add oxygen (or in the case of acid mine drainage raise pH) and it will convert to Fe(3) oxide which is water insoluble giving you banded iron ore and the distinctive orange tint of acid mine drainage.

namelessfly wrote:Exactly.

However; the limiting factor is the amount of Fe-II dissolved in the oceans. Given the low solubility of Fe-II, it should not betokened difficult to provide enough Oxygen to precipitate it out. You would need to provide enough free Oxygen to compensate for more Fe-II being eroded and washed into the oceans.

Castenea wrote:Ummm.... Most iron is not found in reduced form, but as Fe(2) oxide, which is water soluble, add oxygen (or in the case of acid mine drainage raise pH) and it will convert to Fe(3) oxide which is water insoluble giving you banded iron ore and the distinctive orange tint of acid mine drainage.

I think you are seriously underestimating the amount of Iron involved. While the concentration is low, the total amount is quite high. Banded Iron formations were laid down in millimeter layers that are often assumed to be annual increments, the formations can be meters in thickness. Anoxic water often moves and can concentrate iron in geologic formations (e.g. bog iron). Iron is far from the only sink, it is merely one of the more obvious ones. Most of the free Oxygen in out atmoshpere to day is due to the storage of carbon as either coal (sub aerial deposition) or hydrocarbons (subaques deposition) most commonly as shales.

Personal questions for processes that could confound this terraforming include the possibility of massive Limestone deposition in a Carbon dioxide atmosphere. Oolitic limestones are abiotically deposited as they are formed from an evaporitic process. How much soil formation is needed to start on higher plants, these are more efficient than algal plaques and lichens which could be started immediately.