How far?

noosfractal · 2005-10-25 15:28:33

The gravity of a planet plays a large role in what atmosphere a planet can hold.

The gravity of a planet plays a role in how long it can hold an atmosphere, not atmospheric composition (except when you get really low, but I'll assume we're talking about at least luna gravity). Replenishment may be required at some point, but the timeframes we are talking about are very long - thousands to millions of years for Mars. If we can achieve terraforming in the first place, we can maintain it over the long term.
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Siegfried · 2005-10-25 19:01:51

I agree. Most scientists agree that a dense (though maybe not quite that of Earth) lasted on Noachian Mars and perhaps through mid-Hesperian Mars.

chat · 2005-10-26 04:27:03

noosfractal,

I agree that if you can teraform mars it would remain teraformed for a decent period of time.
Maybe a replenishment every 100 years or so, with some luck just mining for greenhouse gas components on mars at a persistent rate would keep up with the planets demands.

My trouble is with the slow teraforming of mars method.
Mars has to go through a point that water can be liberated from the surface to be teraformed.
As soon as water and atmosphere are at the correct proportions it will snow not rain, this is a serious issue to Martian teraforming .
Simply coating 10% of mars in snow will negate any greenhouse gas release project, more gas release at this point will cause more of mars to be snowed on.

De orbiting demos or smashing a large asteroid into mars sets the temperature point above the formation of snow, allowing for a teraformed mars that doesn't go through the arctic catch 22 cycle.

A large impact on Mars might be the only way to Teraform it, with smaller impacts every 100 or so years for replenishment, or a man made planetary magnetic field to keep what it has from radiation stripping from the solar wind.

chat · 2005-10-26 04:52:34

noosfractal,

Gravity, location, temperature, magnetic field are all factors in what atmosphere a planet can hold.

If you could move planets or moons to different orbits it completly changes what happens to them, and what they become.

Siegfried · 2005-10-26 21:44:11

noosfractal,
I agree that if you can teraform mars it would remain teraformed for a decent period of time.
Maybe a replenishment every 100 years or so, with some luck just mining for greenhouse gas components on mars at a persistent rate would keep up with the planets demands.
My trouble is with the slow teraforming of mars method.
Mars has to go through a point that water can be liberated from the surface to be teraformed.
As soon as water and atmosphere are at the correct proportions it will snow not rain, this is a serious issue to Martian teraforming .
Simply coating 10% of mars in snow will negate any greenhouse gas release project, more gas release at this point will cause more of mars to be snowed on.
De orbiting demos or smashing a large asteroid into mars sets the temperature point above the formation of snow, allowing for a teraformed mars that doesn't go through the arctic catch 22 cycle.
A large impact on Mars might be the only way to Teraform it, with smaller impacts every 100 or so years for replenishment, or a man made planetary magnetic field to keep what it has from radiation stripping from the solar wind.

Good! At least you're destroying Demios, not Phobos like they did in Red Mars. I like Phobos so much better. But by doing that, Mars will never have a ring around it!

noosfractal · 2005-10-27 02:08:21

My trouble is with the slow teraforming of mars method.
Mars has to go through a point that water can be liberated from the surface to be teraformed.
As soon as water and atmosphere are at the correct proportions it will snow not rain, this is a serious issue to Martian teraforming .
Simply coating 10% of mars in snow will negate any greenhouse gas release project, more gas release at this point will cause more of mars to be snowed on.

This is actually really interesting - one of the things about climate that we are still only guessing at. Water is such an interesting molecule. You're right. There are scenarios that can lead to a Snowball Mars. Wouldn't that be a terrible irony! To warm the surface 100 degrees and achieve a hydrological cycle that lets it rain and snow, only to lose the planet to a global ice age. But I don't think that nothing could be done. Imagine that is just how we had found Mars today. We would think ourselves lucky.

Snow increases albedo, and a Snowball Mars would be an extreme case, but the greenhouse gases we're planning on using (PFCs) are over 10000 times as effective as carbon dioxide at keeping whatever energy the surface does absorb (almost as good as water vapor). Even if we lost all our water vapor, as long as we keep pumping out PFCs, then at some point the surface temperature will rise and the ice will melt - if the incoming energy can't re-radiate back out into space, then there is really nowhere else for it to go.

A large impact on Mars might be the only way to Teraform it, with smaller impacts every 100 or so years for replenishment, or a man made planetary magnetic field to keep what it has from radiation stripping from the solar wind.

One thing with replenishment - once there is a good atmosphere then, say we had an ammonia comet in Mars orbit, rather than deorbiting the whole comet at once, we could break it up into smaller pieces that would burn up in our new atmosphere and rain down gently. It would take more energy and the continuous stream of comet rain would effect the weather patterns, but it avoids apocalyptic events and it might even provide a weather control system of sorts.
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chat · 2005-10-27 05:30:47

noosfractal,

Sad to think that in an effort to warm Mars up we could easily make a much worse place.

I agree that on a snowy Mars if we continue to release PFCs the temperature will eventually climb above the melt point of the snow and melt everything.

The only down point to that scenario is that when all the snow melts, it will then allow all that lost reflected heat due to the snow cover to be captured by the surface, the atmosphere quickly thickens and the temperature soars to a much higher set point.

Since 4 or 5 times the needed PFCs will exist and persist in the Martian atmosphere it wont cool.
Would that scenario just see mars turned from snowball into a 60c planet or a runaway greenhouse similar to Venus. ?

Your observation of us finding a mars the way it is being very lucky is quite true.
A little bit to warm or to cold makes for a very hard to teraform place.

I don't think anyone would ever allow deimos or phobos to be de orbited, but they serve well for the impact scenario.
I favor one of the big asteroids for the initial collision, i also agree that adding gas to mars can be achieved from smaller ice asteroids if needed without planetary devastation.

We will have to know mars pretty well before we attempt anything, since anything may exist just under the surface.

SpaceNut · 2005-11-03 08:37:24

Here is a refernce thou of Titan it speaks of the Greenhouse effect.
Titan: Greenhouse and Anti-greenhouse

Like Earth, Titan has a greenhouse effect. So does Venus, a whopping one, and so does Mars. Venus is the queen of the greenhouse effect. Ninety-nine point nine percent of the energy reaching the surface of Venus is retained by the greenhouse effect. Titan, though, comes in a close second. Ninety percent of the energy at the surface of Titan is held in by the greenhouse effect. On Earth it's about 60 percent, and on Mars it's down to 30. On Earth, Venus and Mars, the greenhouse effect is due to CO2 and water. Titan's greenhouse effect is the only one that's not from CO2; it's from nitrogen and methane.

Comparison of amrs to Titan:

Mars has an Equatorial diameter of 6,804.9 km, Mass 6.4185×1023 kg, and Rotation velocity 868.22 km/h.
Equatorial gravity 3.69 m/s2, or 0.376g

Titans has an Mean diameter of 5150 km, Mass 1.345×1023 kg, and Rotation velocity which is sychronous to Saturns as noted in wikpedia.
Equatorial surface gravity 1.35 m/s2, or 0.14 g

What other factors are there to aid in atmospheric retention?

SpaceBull · 2005-11-03 15:37:49

The most efficient greenhouse gas is sulfur hexafluoride (SF6), which is 22,200 times as efficient as CO2. If all we want to do is to heat Mars then this gas would be perfect, and it has a lifetime of 3200 years in Earths atmosphere. SF6 is a heavy gas, and it is not going to escape from Mars. The catch is that producing it requires a lot of energy, and even a slow terraforming would require a few power plants equivalent to the biggest ones we have on Earth. If I were living on Mars I would rather have used that power on heating my dome and growing food for my kids unless there is a huge power surplus that can be invested in long-term projects.

chat · 2005-11-03 16:50:45

SpaceBull,

It's a great gas to use to warm mars up.
Same problem still exists with any long term greenhouse gas though.
It takes a lot of any gas to warm Mars enough to liberate any h20 into the atmosphere, it promptly snows out and settles cooling the planet.
Adding more greenhouse gas just makes more h20 for snowfall covering more of the planet. (the snowball effect).

At some point all the snow melts if you continue to add greenhouse gasses, but at that point of total melt a much higher sustained temperature will be held for a long time, due to the multiples of greenhouse gasses needed to melt the snow.

Very easy to go from icy thin cold atmosphere to thick toxic hot atmosphere.

My thought is a big thump for Mars followed by careful greenhouse gas production on the planet, or if we are lucky no gas required afterwards.

Occasional ice asteroids would probably thicken atmosphere and wet mars nicely and be more controllable than huge greenhouse gas releases anyway, at minimum it would be much more efficient to asteroid than gas.

It's probably easiest to make any needed gas from native chemicals on mars, so whatever gas can easily be obtained from the Martian chemistry with little power will probably be the one used.

SpaceNut,

I think it all comes down to location, size, magnetic field and ingredients of a planet.
If we fiddle with placement of any of the planets they become very different places. IE move Mars to Venus orbit and Venus to Mars orbit.
Would should end up with 2 very different worlds.

Move Earth 10% closer to the sun and it becomes much like Venus.

So placement must be the no 1 factor, then wherever a planet or moon is, the rest come into play to make it an individual place.

SpaceNut · 2005-11-03 20:47:01

Well we can not and do not have the capability to move Mars closer so what is the next best thing is what we need to solve for.

In this case what are we doing by move an object closer to the sun. Bingo we are increasing the amount of solar rays or energy recieved. So what possible way can we increase the amount of energy to the planet.
Lets create a pair of Shepherding artificial moons but lets make them reflectors that are parabolic to concentrate the collected energy towards the planet. So problem one has a solution.

Problem two is a magnetic field but are you refering to the radiation belts that occur because of it or of a higher specific gravity? Lets not forget the active filter of uv that the ozone layer affords us as well for we will still need to do the same for mars as well.

Planet ingredient makeup can be fiddle with a bit by imports from Earth but a better source may be near by moons, space rocks (NEO) or comets, and asteriods. Mining what ever is needed to give us a better chance of surviving on mars. But in the same tokenas you notted before gravity is relative to a planets mass and with each cargo of material that we bring to its surface we are increasing its mass ever so slowly but we are doing it just the same. So maybe long term the second problem is solved as well.

srmeaney · 2005-11-04 05:25:26

Just to cut to the chase, how far would you want terraforming to go for you to be satisfied?
As for myself, I would be happy if I could take a stroll on the Martian surface with an oxygen mask, a pea coat, and maybe some goggles to keep out the sand. If terraforming went that far, even not in my lifetime, I would be happy.
Which reminds me of some Martian art by I forget who. I'll try and find it...

Until the red planet is covered in a sea of sugar cane to power the methanol power stations. There is no point in wasting time when only earth like conditions will cut the amount of money that must be spent on sustaining the colony.

SpaceBull · 2005-11-04 05:36:25

Let's say people move to Mars, and start inventing and utilizing all the technologies needed to sustain themselves there. When they have adopted their technologies to the environment they would have no incentives to go into the terraforming business.

SF6 is a heavy gas, and I am actually not even sure that it would mix into the Martian atmosphere. It may sink into the deepest craters instead, and this would make the heating effect very local indeed. Mars would look kind of funny if the 9 kilometers deep Hellas impact basin is the only place that get terraformed. The water vapor might not be able to escape either, making the 2100 kilometer wide crater a possible closed ecosystem.

chat · 2005-11-04 05:53:36

SpaceNut,

It is possible to move a planet in a few ways, none of them are what you would call short term projects or even realistic ones.
Probably not something we will be considering doing for quite some time.
Even if we could move mars to an earthly like orbit it still wouldn't resemble earth.

The idea of Mars receiving more solar radiation to heat its surface is a valid one.

Mirrors, particle beams and greenhouse gasses all do a similar thing at mars to liberate gas into the atmosphere to help heat even more.
Mars being a very efficient surface solar radiation absorber right now, isn't going to get an enormous amount better at retaining more energy from the sun even with a thicker atmosphere.
Mirrors though they could work would require a staggering amount of them to break beyond the snowball stage, i don't believe they are a viable way to heat mars.
Huge particle beams or laser beams liberating gas directly from the surface might be a solution, but on a planetary scale they will also require enormous energy to run long enough to impact the bar pressure past the melt of snow.

Magnetic field is more problematic for mars, without a decent magnetic field mars will simply loose light gas to space at a regular pace, and be a more radioactive place without the gas elements earth holds to fend off UV rays, charged particles etc.

Mars can probably be teraformed without a magnetic field, and just expect to replenish the light escaping gasses as needed, and live with the higher radiations.

Changing the mass of mars to any significant amount to make it hold more of the lighter gasses would be a daunting task, mars would have to be about 2x its mass for this.
Not impossible to do, but impractical.

Mars in theory can be teraformed, but in practice i think it will be exceedingly tough to teraform.
We also have to look at the likely product we would end up with on a teraformed mars to see if teraforming is even viable for the outcome.
A terformed mars might be globally averaging 2c in temperature, 2 psi of toxic atmosphere and much higher charged particle and UV counts.
On this teraformed Mars other than pond life, all the rest of mars will be inhospitable to all but the most robust microbial life.

SpaceNut · 2005-11-04 09:27:23

Burned-up meteors add to Martian atmosphere

A previously unknown layer has been detected in the atmosphere of Mars, which scientists believe is created when meteors burn up high above the planet's surface.
Scientists in Germany and the US found the new layer between 65 and 110 kilometres above the Martian surface. It constitutes a third part of the planet's ionosphere – a region of ionized particles – and lies just beneath two layers already known to exist.
The new layer was detected all around the planet in 10 out of 120 observations, and was not spotted during 20 night-time measurements Martian night.
The two main layers of the planet's ionosphere are created by ultraviolet and X-ray radiation from the Sun, which dislodges electrons from oxygen molecules in the atmosphere.
Scientists believe the third layer is formed as meteors crash through the atmosphere, colliding with molecules and atoms. This process is thought to knock electrons away from magnesium and iron particles within the rocky bodies as they break up, leaving a thin new layer of charged metallic particles in the atmosphere.

This is interesting...

noosfractal · 2005-11-04 13:51:54

Just to cut to the chase, how far would you want terraforming to go for you to be satisfied?
As for myself, I would be happy if I could take a stroll on the Martian surface with an oxygen mask, a pea coat, and maybe some goggles to keep out the sand. If terraforming went that far, even not in my lifetime, I would be happy.
Which reminds me of some Martian art by I forget who. I'll try and find it...
Until the red planet is covered in a sea of sugar cane to power the methanol power stations. There is no point in wasting time when only earth like conditions will cut the amount of money that must be spent on sustaining the colony.

Actually, just having enough surface pressure to be able to dispense with pressure suits will make life on Mars much more comfortable.
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noosfractal · 2005-11-04 14:07:45

SF6 is a heavy gas, and I am actually not even sure that it would mix into the Martian atmosphere. It may sink into the deepest craters instead, and this would make the heating effect very local indeed. Mars would look kind of funny if the 9 kilometers deep Hellas impact basin is the only place that get terraformed. The water vapor might not be able to escape either, making the 2100 kilometer wide crater a possible closed ecosystem.

These sorts of ideas are really interesting - even if we can't get 500 mb planet wide in under 50 years, could we achieve that in the Hellas basin in, say, 5 years? Could it be stable enough?

One of the features in the Valles Marineris area is another possibility.
http://ralphaeschliman.com/atlasofmars/9axsm.pdf
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noosfractal · 2005-11-04 14:17:35

Mars being a very efficient surface solar radiation absorber right now, isn't going to get an enormous amount better at retaining more energy from the sun even with a thicker atmosphere.

Actually this isn't true. Albedo determines how much energy the surface absorbs initially, but then, without greenhouse gases to keep it in, the absorbed energy just gets re-radiated into space - pretty much as predicted for a classic black-body radiator. Greenhouse gases change the situation enormously.
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Dook · 2005-11-04 17:22:57

If SF6 is a heavy gas then we should use that to the best advantage.

What if we placed the super greenhouse gas factories around the Hellas Basin and purposely sent the gas down into the basin to concentrate it. This would increase the temperature of the basin much quicker than the rest of the planet. The basin has some ice and it is also on the edge of the large ice stores at the south pole. This would melt the ice and water would fill in the basin to provide an ocean of water for the use of a science outpost. With the addition of a space mirror I'm sure we could accomplish this rather quickly depending on the location of rock containing sulfur and flourine.

Some water would evaporate from this sea but likely quickly freeze and fall back as snow.

noosfractal · 2005-11-04 21:35:17

Here is a graph from a March 2005 paper titled "Radiative-convective model of warming Mars with artificial greenhouse gases" by M. Marinova and C. McKay ...

It looks like C3F8 turns out to be the best greenhouse gas for Mars - apparently it makes up for the lack of water vapor.
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chat · 2005-11-05 05:44:46

noosfractal,

Surface absorber, not re radiated heat.

Mars right now is quite good at heating the surface with its available solar radiation, other than painting it black it won't get much better.
With a thicker atmosphere mars would retain more of the radiated heat.

All of the greenhouse gas studies I've seen don't take into account the release of h20 becoming snow and negating the surface warming of Mars or even the possibility we could make it much worse.
Mars receives about 400w of heat a meter on its day side, if the release of gas causes just 10% of mars to be snowed on, then the cooling of mars would be
400w/m/1/10 or 40w/m X 6,000,000m X 6,000,000m of cooling.
Since little additional h20 and co2 will be retained in the atmosphere until a total melt, we can expect near 0 warming from the native Martian atmosphere, so the greenhouse gas must be relied on for nearly all of this.

When you factor in this initial cooling of mars the gas release becomes a problem in quantity itself, and the rebound temperature beyond the snow melt also.

Heating Mars with greenhouse gasses looks good until you start looking into the inevitable planetary mechanics of it.

Dook,

Or even just teraform the canyon itself and don't worry to much about the rest of mars.
As you point out its warmer, has a thicker atmosphere and slightly less radiation.
A great place to set up home on mars.

Teraforming just the canyon is within technical reach right now.

Rxke · 2005-11-05 08:51:34

other variables, good and bad, when atmospheric water comes into play:

First: snow, rain, even fog... forms around 'pollution' particles in the atmosphere, so once a serious amount of H2O in the atmosphere forms ice-crystals, it will take a lot of the atmospheric dust with it back down, increasing insolation.
Increased H20 in attmosphere -> increased clouding: bad during the day (less insolation) but very, very good during the night (insulation) Net effect of clouds obviously negative, but it would make regions that otherwise 'freeze solid' during the night retain heat better, maybe keeping regions around the equator above freezing during prolongued periods. big one, that, for primitive life etc.. and if these regions stay above freezing, water can accumulate, which are great heat-reservoirs, forming another 'buffer'

Interesting stuff. Unpredictable stuff, largely, untill some good simulations are being done...

noosfractal · 2005-11-05 14:47:59

Since little additional h20 and co2 will be retained in the atmosphere until a total melt, we can expect near 0 warming from the native Martian atmosphere, so the greenhouse gas must be relied on for nearly all of this.

Remember that the boiling point of CO2 is much lower than H2O (-108 F vs. +32 F). Zubrin estimates that just a 4 K rise in global average temperature would evaporate the Martian poles and yeild an atmospheric pressure of at least 300 mb (and maybe as high as 600 mb)

http://www.users.globalnet.co.uk/~mfogg/zubrin.htm

But the global average temperature would still be -100 F, so all H2O would still be in deep freeze - you'd still have quite a ways to go before H2O snow would become a concern.
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noosfractal · 2005-11-05 14:55:19

Interesting stuff. Unpredictable stuff, largely, untill some good simulations are being done...

Yeah, but it is hard to even begin on a simulation because so many of the basic parameters are unknown. For example, if I heat Martian soil, will it release CO2 or become a CO2 sponge? The first teams on Mars are going to have a lot of work to do 8)
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chat · 2005-11-05 16:10:24

noosfractal,

Only trouble is that the latest information from mars seems to say that most of what is frozen on the poles is water and little frozen co2.
Don't expect much help from frozen co2 if the poles are not packed with it.
Even if enough c02 exists to help rise above the c02 freeze point, it wont be much beyond it, and may make for another problem (co2 freezes planet wide).
Yet another arctic problem to overcome for Mars.

Rxke,
Another few good points for Martian teraformers when h20 finally makes its way into the atmosphere.
I bet many unexpected planetary mechanics will come into play on mars when a teraforming attempt is made.
Would mars produce clouds like on earth, or in patchy bits, or planetary covering ones like titan.
Mars won't be as dynamic a world as earth so you could expect some pretty big mood swings in weather on mars.

I wonder what it would rain on mars?
To begin with i bet a very dirty rain with iron and with trace peroxide from the atmospheric dust and all sorts of other nasties.
Sounds lovely doesn't it, but good for blondes
Probably quite good for pond life also unless the peroxide count doesn't diminish with time.
A lake of bleach wouldn't be a good thing.

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#26 2005-10-25 15:28:33

Re: How far?

#27 2005-10-25 19:01:51

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#32 2005-10-27 05:30:47

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#33 2005-11-03 08:37:24

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#36 2005-11-03 20:47:01

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#37 2005-11-04 05:25:26

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#39 2005-11-04 05:53:36

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