Inhabitable Planets Too Close Together?

One possible, brute force mechanism to transform a CO2 atmosphere into an Oxygen atmosphere.

http://carbon.atomistry.com/decompositi ... oxide.html

http://astro.unl.edu/naap/atmosphere/distribution.html

This thermal velocity issue is well known to planetary scientists. Planetary escape velocity is one critical factor but atmospheric temperature is another. You might not be able to heat the entire atmosphere up butcreatinga region of high temperature where a large fraction of gas molecules are at escape velocity is feasible. If the energy density is high enough to dissociate the CO2, then you will out gas more Carbon than oxygen.

I found this on global river flows.


http://www.pnas.org/content/early/2010/ ... 7.full.pdf

The average volume of 5,000 cubic Kilometers per month is equivalent to 60,000 cubic kilometers per year or 60eex12 m^3 per year or 60eex12 tons per year.

Global surface area 5eex14m^2 @ 10 tons of atmosphere per square meter.
(I got the Lap Lab offmy lap to use my calculator so my numbers are a bit more accurate.)

So global river flows equals one Earth atmosphere every eight years.

The reason why I of fee this data is that humans already impede, impound and manipulate most of the global river flows at some point and often multiple points, so manipulating this volume for terraforming is not absurd.

Just FYI, 60eex12 m^3 per year = 2eex6 m^3 per second.

Assuming a flow velocity of 100 meters per second then you need a pipe with an area of 2eex4m^2 or about 140 meters in diameter. This is not an absurdly large, orbital plumbing fixture for a space based civilization.

My point is that we can use a relatively modest sized lightsail to boil off extra atmosphere, then use the same light sail to vaporize and distil a few comets to make a new atmosphere.

namelessfly wrote:Go back to my earlier post where I calculated the energy requirement for making the Oxygen. Given the ability to build a fusion rocket for a Colony ship, it is doable. It is just difficult to wrap your mind around the implications of fusion rocket technology. Even an interstellar colony ship propelled by a light sail would be able to massively alter a planetary environment.

I really don't understand why you keep harping on the energy cost. I have already stated several times that I agree that energy is not the limiting factor on terraforming with Honorverse technology. Nor is flow rate the problem. PLEASE stop talking about that!

The problem you have not addressed directly is how fast can you convert the oxide into oxygen. 1.2 billion tons per second PRODUCTION is enormous. Not flow--production. You have vaguely mentioned rapid chemical processes, but you have not yet convinced me that this production rate is possible unless you have already heavily industrialized the planet.

I think earlier I noted the energy needed to dissociate CO2 and then addressed the equilibrium temperature and hence radiant energy density needed to get a large fraction ofCO2 to dissociate. This can be done brute force with high production volume by using a moderately large light sail to focus solar energy into an air parcel. Sincefree Carbon atoms have a much lower molecular mass than Oxygen atoms, they Maxwellian thermal velocity distribution will result in the Carbon atoms being ejected out of the atmosphere into space at a much higher rate than the Oxygen molecules. You convert a CO2 atmosphere into an Oxyge atmosphere by cooking it over a few decades.

SWM wrote:

namelessfly wrote:Go back to my earlier post where I calculated the energy requirement for making the Oxygen. Given the ability to build a fusion rocket for a Colony ship, it is doable. It is just difficult to wrap your mind around the implications of fusion rocket technology. Even an interstellar colony ship propelled by a light sail would be able to massively alter a planetary environment.

I really don't understand why you keep harping on the energy cost. I have already stated several times that I agree that energy is not the limiting factor on terraforming with Honorverse technology. Nor is flow rate the problem. PLEASE stop talking about that!

The problem you have not addressed directly is how fast can you convert the oxide into oxygen. 1.2 billion tons per second PRODUCTION is enormous. Not flow--production. You have vaguely mentioned rapid chemical processes, but you have not yet convinced me that this production rate is possible unless you have already heavily industrialized the planet.

namelessfly wrote:I think earlier I noted the energy needed to dissociate CO2 and then addressed the equilibrium temperature and hence radiant energy density needed to get a large fraction ofCO2 to dissociate. This can be done brute force with high production volume by using a moderately large light sail to focus solar energy into an air parcel. Sincefree Carbon atoms have a much lower molecular mass than Oxygen atoms, they Maxwellian thermal velocity distribution will result in the Carbon atoms being ejected out of the atmosphere into space at a much higher rate than the Oxygen molecules. You convert a CO2 atmosphere into an Oxyge atmosphere by cooking it over a few decades.

That is a plausible method for converting CO2 into oxygen, though you neglect the fact that, as it cools, the oxygen atoms are just as likely to combine with the carbon atoms as they are with other oxygen atoms. And if you are doing this in the planetary atmosphere, these hot oxygen ions will likely be combining with lots of other elements as well. Only a fraction will end up as free oxygen. And if you are simply applying this to the ambient atmosphere, then once you start getting significant quantities of free oxygen, you will be dissociating oxygen molecules as well as CO2. You will reach an equilibrium where oxygen is being destroyed as fast as it is being created. I expect that the equilibrium will leave too much CO2 and CO in the atmosphere.

And you still haven't dealt with the production rate. Are you suggesting using your solar sail to cook on the order of one trillion cubic meters of carbon dioxide per second?

Given the energy budget you're talking about, I have this vision of the planetary surface melting, which potential colonists would possibly regard as suboptimal. What am I missing?

JohnRoth wrote:Given the energy budget you're talking about, I have this vision of the planetary surface melting, which potential colonists would possibly regard as suboptimal. What am I missing?

It gets better over time.

Yes

SWM wrote:

namelessfly wrote:I think earlier I noted the energy needed to dissociate CO2 and then addressed the equilibrium temperature and hence radiant energy density needed to get a large fraction ofCO2 to dissociate. This can be done brute force with high production volume by using a moderately large light sail to focus solar energy into an air parcel. Sincefree Carbon atoms have a much lower molecular mass than Oxygen atoms, they Maxwellian thermal velocity distribution will result in the Carbon atoms being ejected out of the atmosphere into space at a much higher rate than the Oxygen molecules. You convert a CO2 atmosphere into an Oxyge atmosphere by cooking it over a few decades.

That is a plausible method for converting CO2 into oxygen, though you neglect the fact that, as it cools, the oxygen atoms are just as likely to combine with the carbon atoms as they are with other oxygen atoms. And if you are doing this in the planetary atmosphere, these hot oxygen ions will likely be combining with lots of other elements as well. Only a fraction will end up as free oxygen. And if you are simply applying this to the ambient atmosphere, then once you start getting significant quantities of free oxygen, you will be dissociating oxygen molecules as well as CO2. You will reach an equilibrium where oxygen is being destroyed as fast as it is being created. I expect that the equilibrium will leave too much CO2 and CO in the atmosphere.

And you still haven't dealt with the production rate. Are you suggesting using your solar sail to cook on the order of one trillion cubic meters of carbon dioxide per second?

JohnRoth wrote:Given the energy budget you're talking about, I have this vision of the planetary surface melting, which potential colonists would possibly regard as suboptimal. What am I missing?

Your a few orders of magnitude short of the energy budget to com the planetary surface