Terraforming

[Steve Long]

An article that may be of interest:

 

http://www.1point1c.org/terraform.html

[Erkenfresh]

Re: Terraforming

 

That's a pretty cool article. It seems the only hope we have is to find planets that are just like Earth already. Or we could create human variants like in Terran Empire.

[Ockham's Spoon]

Re: Terraforming

 

Interesting article, thanks for sharing. I still think colonizers would have planetary bases though just to be able to exploit the natural resources there. They might live on a space station, but they have to get the materials to build the station from someplace and shipping large quantities of material interplanetary or interstellar distances isn't easy. Also you can't do a comprehensive scientific study of a planet without actually visiting it. That said, robots would likely play a large role in extraterrestial exploration and exploitation.

[Nolgroth]

Re: Terraforming

 

Meh. Another pessimistic article with little vision or accounting for technological advances that will likely come down the line in the next few decades, let alone centuries.

 

Besides, some of the more interesting terraforming articles I've read involve smashing large asteroids into Mars in order to increase the size and density. Not sure how realistic those articles are, but the smashing rocks into Mars bit sounds very fun.

[L. Marcus]

Re: Terraforming

 

The entire asteroid belt would hardly make a bump in Mars' mass.

[NuSoardGraphite]

Re: Terraforming

 

The entire asteroid belt would hardly make a bump in Mars' mass.

 

What is the mass of Mars compared to that of the Asteroid belt (estimated I assume)

[NuSoardGraphite]

Re: Terraforming

 

ok I found it. It is estimated to be only about 4% of the mass of the moon. Hardly noticeable to Mars.

[Gnaskar]

Re: Terraforming

 

Gravity issues:

No real studies have been made on the long term effects of low and/or high gravity on humans, animals or plants. The minor studies that have been done are listed as inconclusive. Depending on which scientist you ask the survivable range is anywhere from 10% to 90% (.9 to 1.1 G or .1 to 2 G) but most of them admit that this is pure guesswork. Best answer I've gotten to the question "can humans survive with Mars gravity" came from astronaut Story Musgrave: "I know of only one place we can figure that out".

 

We have no idea whether bone degradation occurs exclusively in microgravity situations. The best current theory is that a gravity dependent mechanism is responsible for replacing the calcium lost naturally by the body, which shuts down in free fall. This mechanism would function perfectly until some currently unknown threshold before shutting down completely. In short: lower gravity does not necessarily mean bone loss.

 

Muscle loss is, as far as we know, fully reversible. It even happens naturally with no outside interference. After six months on the ISS, returning astronauts immediately start gaining muscle mass as they start going about their daily lives on Earth.

 

So: Too little gravity, up to an unknown point, does no permanent harm to the human body based on our current limited understanding of the effects of gravity. I'd like to be more precise than that, but at least I'm not making any assumptions.

 

We known only one thing about higher gravity environments: they cause increased muscle growth proportional to the increase in gravity. Beyond a unknown point this causes various heart problems and the like, but for the most part it is fairly healthy.

 

Day length:

Today the city I am in had four and a half hours of daylight. Six months ago that was the length of the night. Apparently life here as adapted to handle this just fine, while life near the equator functions perfectly on their unchanging 12 by 12 hour schedule. So excuse me if I don't believe that the length of the day is a show stopper. Life adapts; pretty much by definition. You might see sort term stress or even some long term issues (see Winter Depression) but its not going to do significant damage to the prospects of colonization. And even if it did, the author completely ignores bio-engineering as a potential solution.

 

For the last week or so I've been slipping into a 26 hour day schedule due to sickness and a lack of tasks I have to get up to do. Last year, exam reading and stress pushed me into a 6 day week of 28 hours per day which I kept up for most of a month before the Christmas holidays forced me out of it. I highly recommend it for people who have the chance to try it; you get a lot more done in a week that way. So, again, I'm not convinced.

 

I'd also like to point out here that a martian day is 24 hours and 38 minutes. That's a 2.6% difference.

 

Year length:

My very first through is "why stop at Jupiter's 12 years?" Neptune's 168 years would have been more impressive. As would Pluto's 248 year orbit. Seems a bit arbitrary, especially since he's already noted that Pluto's gravity would, in his eyes, be more favorable than Mars.

 

Again, everything he says here is pure guesswork. Some of it I even recognize from theories from the middle ages that have since been proven to be complete bull. Most notably: why would birth be linked to seasons? A pregnancy takes X days (plus to minus a couple) for a given species. Unless the exact day the pregnancy occurred is also based on seasonal milestones then the variation in when the birth took place verses when the fetus was ready would be too large even before you note that yearly variations of the season can push any given milestone around by weeks. What can give you trouble is that variations in climate (the perceived season) can effect mating seasons; potentially even stop them from occurring. Which is a problem, yes, but one solvable with medicine, climate control or (in the long term) genetic-engineering.

 

As for clocks and calenders: We have a concept called Local Time. We use it to resolve these issues.

 

The glass dome at the bottom of the ocean:

Lets see: No sunlight below 1km and the ocean averages about 3.8km deep. So all the year and day issues are out the window (making the ocean equivalent to Titan and other Saturn colonies in that regard). That has already made the section this comment was in irrelevant but lets not stop there. At 3.8km below sea level the pressure is about 380 atm. That means a colony would need to maintain a difference of 379 atm, while a lunar colony would for comparason need to maintain 1 atm of difference. I'll let you guess which of these are easier. The bottom of the ocean has, effectively, the same gravity as the surface, granted, but as I've already pointed out, he's talking out of his backside when it comes to the effects of gravity anyway.

 

Terraforming tools:

These all address atmospheric composition. Nothing in the rest of the essay deals with that issue at all. Unprofessional, Mr Thompson.

 

On a separate note, I love how "heats the planet" is considered a disadvantage of one of the terraforming techniques. More heat is exactly the best way to terraform Mars.

 

Conclusion:

Bull.

 

I have nothing more to say about it.

[Xavier Onassiss]

Re: Terraforming

 

In the context of most SF RPGs, the most pessimistic thing about thing about the linked article is that it only looks at planets in our solar system. I think its conclusions are valid for the planets available here, but what about other star systems?

 

In a SF RPG campaign focusing on our own system, that's fine, as far as it goes. However, many SF campaigns focus on interstellar travel, exploration, "boldly going" etc. The question for those games is, for hypothetical planets orbiting other stars, what are the limits of terraforming? How large/small, how close/far from its star, how fast or slow in rotation can a world be and yet still be a candidate for terraforming? (Axial tilt, atmosphere, there are other factors too.) Obviously the candidate worlds in our system all have "deal killer" characteristics that put them outside one or more of these limits, but that doesn't tell us where exactly the boundaries are.

[Cancer]

Re: Terraforming

 

I admit I think he's being wildly optimistic, and I also think he's written this as a project that merits at best a C+ in a 101-level course. I see almost nothing in the way of numbers.

 

The exception to my thinking that he has the optimism of the utterly clueless is ... "day length" is irrelevant for things in the outer solar system ... there's not enough solar energy to matter to anything ... and if you have managed to get your tech to the point that you can live in space long enough to launch a terraforming project, you've already demonstrated that "year length" is also either irrelevant or something you can simulate adequately. So his points about those natural planetary cycles IMO betrays he hasn't done a lot of thinking about the actual physics involved.

 

(What did he use for the "surface" of the giant planets? He doesn't say, at whch point I whack him another few points off hiis grade. I could work out what numbers he's using, but there is no surface. In a jovian planet the atmosphere grades smoothly into the main body of the planet. As you go deeper the pressure is higher, and more matter is present in droplets (or ice crystals) than there was higher up. And there is some point (rather deep) where the volume fraction in the liquid phase is higher than that in the gas phase, but that location certainly is not a sharp edge. That means you've got no surface to build on, and while you can in principle build floating cities and factories and so on, if you're going to be altering the conditions of the planet you're floating in, floatation as you change the atmosphere is not quite so simple as mere floating. OK, technically, there is an edge down there somewhere, where the H-He-CNONeS outer envelope ends and the silicate-iron core begins. In Jupiter and Saturn, however, that depth is below the liquid metallic hydrogen layer, and that begins at megabar pressures, which is nothing like a survivable condition. So no, there is no surface.)

 

The solar energy density at Saturn is slightly more than 1% of what it is here at 1AU. At that level it costs you more to deploy and maintain solar panels than the energy you collect from them. It's just about the same problem at Jupiter. Unless, of course, you've waited 5 Gyr for the Sun to enter the red giant phase of evolution, and well before then you have an entirely different problem to deal with.

 

Sunlght isn't a problem for using microbes. It is clear that the first microorganisms on Earth were chemosynthetic autotrophs; I have seen the case made that the abiotic origin of life on Earth did NOT require solar energy input. (This is why Europa is so interesting as a potential live-bearng world: it gets no solar energy input, but it has plenty of tidal heating in the interior to keep the geology active and the subsurface ocean liquid.) Earth's oxygen atmosphere IS a product of photosynthetic organisms (chiefly cyanobacteria), but it took 2 to 2.5 Gyr to turn Earth's originally reducing CO2 atmophere into an N2-O2 oxidizing one. And that despite the inherent advantage that photosynthesis has: you get rather more energy per reaction cycle out of photosynthesis than any of the chemosynthetic metabolism cycles. There are still chemosynthetic microbes going great guns on Earth, though a recent re-estimate of the total mass of the deep biosphere has put at 0.1 to 1.0 times the mass of the surface biosphere rather than the initial 10 times that was originally speculated.

 

And microbes don't do you a f***ing iota of good if you don't have an atmosphere or hydrosphere to work with.

 

Nanotech is handwavium, so I have no comments about it at all.

 

Low gravity and human-tolerable surface conditions combine to mean that the planet is not going to be able to maintain an atmosphere, period. The atmosphere will escape to space over long (millions of years) periods of time. And before you say, "meh, I don't care about things that take that long", that's about how long it's going to take you to complete the terraforming operation in the first place. In other words, the precious atmosphere you want is escaping to space at a rate that's at the very least comparable to how fast you're forming it. But Earth is the highest-gravity terrestrial planet, and if you go to the outer Solar System, then you either have deal with gas giants, or you're at multi-kilometer depths within the moon, or you're tottering around on a surface that is at temperatures under 100 Kelvin, and water is the dominant rock, not a liquid.

 

Now, it would have been a more worthwhile project if he'd grabbed numbers for some of the more hospitable-seeming (or, perhaps, more typical-seeming) exoplanets and made comparisons with Solar System bodies in this context.