Terraforming Questions

[Jeff M. Hopper]

Terraforming questions for the Group!

A) How long would a breathable atmosphere last on a world with no method of replenishment? How long before the air just escapes due to lack of gravity per world size and atmosphere type?

B) What kinds of organisms would go into a Standard Terraforming Package to be seeded on worlds slated for human development?

 

[whulorigan]

Terraforming questions for the Group!

A) How long would a breathable atmosphere last on a world with no method of replenishment? How long before the air just escapes due to lack of gravity per world size and atmosphere type?

It wouldn't necessarily even be a matter of escaping due to insufficient gravity. Oxygen is highly reactive (which is why the presence of free oxygen in an atmosphere is a possible sign of life - to be there, some chemical process must be replenishing it). Even with sufficient gravity to hold a standard atmosphere, without replenishment over a long period of time the O₂ will likely oxidize local minerals and chemical compounds.

Unfortunately, I cannot give you a good timescale for these processes off the top of my head.

 

[coliver988]

It would also depend on, as asked, planet size but also what was already there (any atmosphere, planetary composition, any existing life, etc), type of star and distance from the star, and a bunch of other factors that would make this quite a few charts to put into game terms.

Found this handy overview which goes into some details: https://www.universetoday.com/127311/guide-to-terraforming/

 

[Enoki]

Add magnetic field or some other means of blocking solar wind that would strip the atmosphere off it like Mars' has been done.

 

[Timerover51]

Terraforming questions for the Group!
A) How long would a breathable atmosphere last on a world with no method of replenishment? How long before the air just escapes due to lack of gravity per world size and atmosphere type?

Stephen Dole, in his book Habitable Planets for Man, which can be found online, has a discussion of this, but the book dates from 1964, so does not take into account all of the planetary data since then. However, I think that his basic view still holds true. The larger the planet, and the greater the gravity and escape velocity, the greater the ability of the planet to retain an atmosphere. A reasonable guess, based on Dole's book, would be a few thousand years at most.

B) What kinds of organisms would go into a Standard Terraforming Package to be seeded on worlds slated for human development?

That is going to be based on what you have to start with on the planet in terms of atmosphere, hydrographic percentage, land percentage, and planet size and distance from the primary star. I would say that a terraforming package is going to be tailored to the planet being terraformed. A terraform package for a planet like Venus is going to be totally different from a package for a planet at the far end of the Habitable Zone, where cold is a major factor.

 

[whartung]

Stephen Dole, in his book Habitable Planets for Man, which can be found online, has a discussion of this, but the book dates from 1964, so does not take into account all of the planetary data since then. However, I think that his basic view still holds true. The larger the planet, and the greater the gravity and escape velocity, the greater the ability of the planet to retain an atmosphere. A reasonable guess, based on Dole's book, would be a few thousand years at most.

That's what I was thinking. i.e. "a long time."

If you can get the atmosphere settled in the first place, then, in terms of human lifetimes, it's "enough" to boot strap the world and let other mechanisms develop over time to maintain the atmosphere.

This thread tickled a vision. Imagine being on a world that's being actively terraformed. The domes are just opening up, but the process continues.

The process is the continual bombardment of comet fragments on the other side (i.e. uninhabited side) of the planet.

Just kind of imagine a world where a Tunguska event happens every few hours.

I wonder what that would be like.

 

[robject]

This thread tickled a vision. Imagine being on a world that's being actively terraformed. The domes are just opening up, but the process continues.

Green Mars by Kim Stanley Robinson. Or, perhaps, Blue Mars. A technical manual disguised as a novel. It had some neat ideas in it, but they weren't worth the time it took me to slog through all three novels.

 

[whartung]

His fundamental premise was digging "mo holes" deep in to the crust to let heat out to thaw the water (as I recall, I read all 3...but it's been awhile).

 

[chipla]

I vaguely remember from my distant youth a documentary by the BBC where they talked about terraforming Mars.

They used a mixture of co2 generation, nukes and dropping ice rocks from orbit. I vaguely remember the voiceover giving 500years as the most wildly optimistic time, with a thousand or more being more likely.

Then again this is BBC science (and 15 years or more of my piss poor memory) so value may vary.

 

[kilemall]

Problem is most planetary projects are going to involve time and/or unthinkable energy if done by physical means. The same amount of effort is more likely to get workable space in an orbital platform, and/or altering/engineering the humans to live on the planet as is.



Barring that, best move is probably to drop off some aggressive microbes to do your terraforming for you. After all, the Earth was methane-based until our oxygen-issuing bacteria showed up and slow murdered the previous biosphere in favor of ours. Something a little more engineered might speed things up.

At the extreme you could biobomb a world with something like the biome supremacy weapons of the Cthhorr.

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


In any case of terraforming you will have to deal with whatever morality is involved in wholesale murdering the native life, which any terraforming of whatever technique is bound to do.

Also, any bioforming you introduce that is aggressive in nature will need to have an off switch so that any 'tools' that hitchhike offworld doesn't destroy your other worlds, and you can settle on it after the planet is 'ready' without side effects.

Finally, on the topic of seeding the planet you are going to need a complex balanced biome with the ability of the local flora and fauna to eat and fend off introduced species at whatever role/size, as will inevitably happen in an interstellar society.


Could be your first indication of another interstellar empire is running into planets they have already bioformed, no settlers or just outposts, seeding hundreds or thousands of years in advance, and you signal your boundaries by seeding yours. Overwriting the other seeded worlds may be cause for war, even though no individuals or fleets have met.


World Tamer's Handbook has a nice bit on what atmospheric gases would be retained per gravity level per world size. That's a good starting point for doing hard science atmo.

I don't know to what extent it would be functional to build up atmosphere only to have it bleed out. Starting up a magnetic core isn't casual either, and may not be possible on metal-poor planets. If you have the energy to manipulate on that scale, might as well build your optimal planet outright.

 

[whartung]

I enjoyed the Chtorr series when I stumbled across all 4 of them in the early 90's. Gave up on the rest them ever coming out.

GURPs also did a Chtorr book.

 

[Nathan Brazil]

The 2300 core books also had some data on gases retained during planet generation based on planet size and density. IIRC it was minimum molecular weight (? MMW).

 

[Straybow]

Oxygen generation is no longer considered the exclusive province of life. Oxygen would be constantly replenished from water vapor being dissociated by high energy UV and cosmic rays, much as ozone is replenished by UV. As long as there is liquid water there can be oxygen in the atmosphere.

 

[kilemall]

Oxygen generation is no longer considered the exclusive province of life. Oxygen would be constantly replenished from water vapor being dissociated by high energy UV and cosmic rays, much as ozone is replenished by UV. As long as there is liquid water there can be oxygen in the atmosphere.

So perhaps Traveller worldgen should have the roll for atmo be 2D-7+Hydro?

 

[Enoki]

I actually have worked out a system for terraforming in Traveller. The system really doesn't fit the game because the time involved is generally years to centuries. But it does work pretty well. It's in a Word file format and about 1300 words long.

 

[mike wightman]

It's a concentration thing - disassociation of water molecules will produce oxygen in the upper atmosphere, and ozone for that matter so you will have oxygen present, but in very small amounts. A large concentration of oxygen is pretty much only possible with a photosynthetic like reaction, free oxygen in the atmosphere is going to quickly react with stuff so is only going to remain as a taint (yes the taint in a Traveller tainted atmosphere could be the small amount of oxygen present in a CO2 atmosphere).

 

[willtron3030]

I actually have worked out a system for terraforming in Traveller. The system really doesn't fit the game because the time involved is generally years to centuries. But it does work pretty well. It's in a Word file format and about 1300 words long.

Many of us would love to see it, I'm sure.

 

[willtron3030]

Gave up on the rest them ever coming out.

So did David Gerrold, methinks.

 

[Straybow]

It's a concentration thing - disassociation of water molecules will produce oxygen in the upper atmosphere, and ozone for that matter so you will have oxygen present, but in very small amounts. A large concentration of oxygen is pretty much only possible with a photosynthetic like reaction, free oxygen in the atmosphere is going to quickly react with stuff so is only going to remain as a taint (yes the taint in a Traveller tainted atmosphere could be the small amount of oxygen present in a CO2 atmosphere).

Water (often the oxygen in the water) reacts with the same things as atmospheric oxygen. Rainfall supplies enough water to react with surface minerals. As long as there is enough water for an evaporation-precipitation cycle, oxygen will build up in the atmosphere rather than being consumed by minerals. Might not even require millions of years.

So perhaps Traveller worldgen should have the roll for atmo be 2D-7+Hydro?

Planet size has more effect on retaining atmo in general. World gen only has a small chance of producing tainted atmo, which is probly all wrong. If we ignore gas giants, our system has 2 out of 3 atmospheres tainted, or 3 out of 4 if Titan counts.

 

[Ulsyus]

I actually have worked out a system for terraforming in Traveller. The system really doesn't fit the game because the time involved is generally years to centuries. But it does work pretty well. It's in a Word file format and about 1300 words long.

Care to post it? There's still opportunities for PCs to get involved in dramas around ongoing terraforming projects, projects almost at fruition, and planned projects running into local resistance (or needing the PCs in the resistance).