Can we turn Mars into another Earth?

[Simon39759]

From what I think to recall, loss of atmosphere into space is a relatively slow process, so unlocking a vast amount of gazes (like the C02 trapped on the martian ground) reasonably quickly will result in an increase of the atmospheric pressure for a few hundred years.

This would also result in an increase in greenhouse and provide raw material for photosynthesis (probably using bio-engineered organisms at first).

Also, people already adapt to lower atmospheric pressures by producing more red blood cells, in fact, training at higher altitude is a strategy for some marathon runners. The Himalayas are about a third of the normal atmospheric pressures and people are able to climb them presumably a relatively heavy efforts there.

So, as far as I know, it is not out of the question that Mars atmosphere could be made somewhat breathable, survivable, at least.

 

[Vorpal]

Why? We have plausible plans for building colonies now. Besides we're talking of time where the alternative is engineering an entire planet.

Engineering an entire planet is a lot easier by many orders of magnitude. You're right in that planets are probably far from the most efficient way of expanding real estate. But Dyson spheres are just too far out there to be a serious competitor with planets.

The specific tensile strength of a Dyson sphere of radius R has to be at least GM_sun/(2R), which for R = 1.0AU comes out to be 4.4E8 Nm/kg. Carbon has the strongest bonds out of any element in the periodic table, and that's already ten times the specific strength of the tiny carbon nanotubes manufactured today, and probably more than even their theoretical maximum. Not to mention that this would require more carbon than is available in the solar system (not counting inside the Sun). A small Dyson sphere around a fainter star might be physically possible. But compared to that, compacting some junk to make a ball in space is trivial, because it doesn't involve vast manufacture of materials at the edges of physical possibility. Making it livable is no harder than on making the Dyson sphere surface so--probably easier, because the engineered planet would have gravity.

On that scale, probably a very slowly rotating Ringworld would be best (spun just right to cancel most of the stress due to star's gravity). But there are smaller, more accessible alternatives as well.

 

[RecoveringYuppy]

@Vorpal,

You're actually describing a Dyson Shell which has a lot of big problems. A Dyson Sphere (or swarm) isn't a single solid object. We probably know how to start building one now.

 

[GreenLines]

The trillion people I was talking about would be people who may never have been on Earth.

10-11 billion humans alive in the past 10,000 years (just throwing it out, don't know the closer figure), with a guess of 10 billion continuing every 50 years... that would be five millennium before we'd have terraforming capabilities. I would guess that it would happen within the next five hundred with limited ability.

 

[RecoveringYuppy]

@GreenLines, I didn't mean merely "not born" yet. I mean they probably won't live on Earth during their own lives. And we could reach a trillion in population a few centuries after we first establish a self sufficient colony off Earth. Can't estimate a date for that. Seems to mostly be when someone decides to do it.

 

[GreenLines]

@GreenLines, I didn't mean merely "not born" yet. I mean they probably won't live on Earth during their own lives. And we could reach a trillion in population a few centuries after we first establish a self sufficient colony off Earth. Can't estimate a date for that. Seems to mostly be when someone decides to do it.

I think I'm starting to follow you, but a trillion still seems like a far off amount.

 

[Cainkane1]

Lakes and pools would exist on mars if it could be heated up. Waters there already.

 

[RecoveringYuppy]

I think I'm starting to follow you, but a trillion still seems like a far off amount.

Exponential growth can be hard to grasp. If our current population were to grow at 2% a year for 600 years we'd be at a trillion. 3% puts us there in 175 years.

At the moment, it appears that we're headed for ZPG here on Earth. But if we opened up space as a place to settle it's hard to say what would happen. And a lot hinges on whether we develop a technology that would allow widespread emigration for Earth or if the space population grows from a small seed group.

Also consider that a mere 110 years ago we didn't have airlplanes. Now the US airlines have a fleet of airplanes that could evacuate North America in a year if need be. Industrial growth can be as staggering to imagine as population growth. Who is to say it's impossible to we won't be able to mass produce rockets enough to evacuate the planet over the next 200 years? Or that we won't come up with something better than rockets?

 

[RecoveringYuppy]

Lakes and pools would exist on mars if it could be heated up. Waters there already.

At the moment, Mars has the same land area as Earth. But that's only because it has no oceans. If we were to terraform it (without increasing it's mass, size or gravity), how much land would it have after oceans? Depends on the depth of the oceans, of course, but no matter how you answer it every answer underscores how hard (or virtually impossible) to make Mars like Earth by any reasonable meaning of "like".

I've never been able to conceive of a scenario where we can terrafrom Mars, but can't live comfortably in space. Most scenarios for terraforming presume a huge industrial presence in space. And if we're comfortable in space, the resources of open space compared to the limited resources of the surface of a planet will make the decision to come back to the surface of a planet a very daunting one IMO.

 

[GreenLines]

Exponential growth can be hard to grasp. If our current population were to grow at 2% a year for 600 years we'd be at a trillion. 3% puts us there in 175 years.

My problem isn't with the exponential growth, it's with the sustainability (yeah, I know, cliche buzzword) of having so many people. Yes, we can probably sustain ten or twenty more billion people on the planet, but these are under more optimal conditions. In space the ability to grow food is going to be a huge challenge to supply enough food to keep up pace with exponential growth.

 

[Simon39759]

At the moment, Mars has the same land area as Earth. But that's only because it has no oceans. If we were to terraform it (without increasing it's mass, size or gravity), how much land would it have after oceans? Depends on the depth of the oceans, of course, but no matter how you answer it every answer underscores how hard (or virtually impossible) to make Mars like Earth by any reasonable meaning of "like".

I've never been able to conceive of a scenario where we can terrafrom Mars, but can't live comfortably in space. Most scenarios for terraforming presume a huge industrial presence in space. And if we're comfortable in space, the resources of open space compared to the limited resources of the surface of a planet will make the decision to come back to the surface of a planet a very daunting one IMO.

Depends of your level of terraformation, I'd think.
At this point, it would be easier and cheaper to install a population in domes than in outer-space.
Industrial process would naturally reject green house gazes and that alone would be some terraformation.
You could add in a few orbital lasers to heat up the gazes out of the ground, or a few orbital mirrors (very thin reflective material) and you are still pretty cheap compared to even a single big orbital base for your population.

But, yes, were are still very far of from turning Mars into a second Earth...

 

[RecoveringYuppy]

In space the ability to grow food is going to be a huge challenge to supply enough food to keep up pace with exponential growth.

That's a problem now, and people 100 years ago probably couldn't imagine doing all the things we do today. So think about it from the point of view of a future where we have established the first self sufficent off world colony. Self sufficient means we presume they can grow their own food and repair their own colony. In most scenarios for building a colony the people who built the colony would also likely be amongst the first residents.

Now what's to stop that colony from building a second one when they need it? What stops that colony from growing and it's capacity to increase food production from growing along with it?

In fact the second one will presumably face lower costs of bring stuff up from Earth.

The only thing I can think of that would stop them would be energy and materials. So the "near term" limits would be the total energy output of the Sun and material mass of the asteroids, comets and most Moons. Not much of a limit until the population reaches in to the quadrillions.

There certainly are lot of uncertainties about us ever getting the first self sufficient off world colony, but once we do, what stops it from growing?

 

[Ferguson]

This may be a bit off-topic, but this thread has me wondering. If in the future, humans are spread out in the galaxy, and amongst other galaxies, wouldn't they be in different gravity-wells and therefore experience different time-dilations? So I might go to my vacation home on Vega IV for a few years and return with only a few months having passed?

Could be that the winner of World War X will be the nation that has the most relative 'time' for advancing technology or eugenics... building tanks and space marines for 100 years while your enemies only experience 2 or 3 ...

 

[RecoveringYuppy]

Ferguson,

Unless you're thinking of taking up residence on neutron stars (cue Robot Forward) the gravity wells aren't deep enough to make that a noticable concern.

Only travelling near light speed will get the time dilation necessary for your scenario.

 

[Roboramma]

There certainly are lot of uncertainties about us ever getting the first self sufficient off world colony, but once we do, what stops it from growing?

I agree with most of what you're saying, but I don't think it's quite as easy as that. For instance, the first self-sufficient colony may be self-sufficient as continuing to survive, but that doesn't mean that they have the excess resources necessary to build another colony. They may have just enough to repair damaged parts (or have something worth trading that is just valuable enough to get new parts shipped up from earth), but building a whole new colony is more expensive than just maintaining the current one, so the ability to maintain this one doesn't demonstrate the ability to create a new one.

Mind you, I think it likely that they, or at least some future similar colony, will have that excess in resources necessary to take the next step, but I don't think it's clear that they necessarily will.

 

[bruto]

To the OP: No, we're far too busy turning the earth into another mars.

 

[Soapy Sam]

What we need to do, is move Venus out to where Mars is.

 

[GreenLines]

That's a problem now, and people 100 years ago probably couldn't imagine doing all the things we do today. So think about it from the point of view of a future where we have established the first self sufficent off world colony. Self sufficient means we presume they can grow their own food and repair their own colony. In most scenarios for building a colony the people who built the colony would also likely be amongst the first residents.

I look at it from the perspective of pessimism. If we are able to build a colony off world that could sustain itself I can only see it as being able to barely do so. Include in that it could build and grow without outside influence, which would probably take some time, then yes, eventually we could have a trillion people in our solar system, but at that point we would probably be burning through resources so quickly that we'd only have a couple billion through rampant starvation and disease.

 

[Vorpal]

@Vorpal,
You're actually describing a Dyson Shell which has a lot of big problems. A Dyson Sphere (or swarm) isn't a single solid object. We probably know how to start building one now.

Whoops. You're right. Vocabulary malfunction.

 

[Simon39759]

What we need to do, is move Venus out to where Mars is.

Well, now that's an idea. Or combining the two, that would produce something quite similar to Earth (and; if we are talking about hading enough material to multiply Mars size by 10, moving Venus should be in the realm of possibility).
But then, it would take a few millions years to cool off the energy from the aggregation process; also, I wonder how the move would affect the Earth orbit?