Venus vs Mars vs Titan

nickname · 2007-03-18 04:20:07

SpaceNut,

1 Bar of Venus atmosphere would be perfect for mars.
The 1 bar of co2 would put Mars at similar temperatures as on Earth.

C02 separators for breathing apparatus on suits and habitat bases.
Outdoors pretty toxic to most life though, so engineering of plants for the surface a must.
Life in ponds shouldn't require much alteration or maybe none.

Now just the small problem of getting 1 bar to Mars.

cIclops · 2007-03-18 04:44:04

1 Bar of Venus atmosphere would be perfect for mars.
The 1 bar of co2 would put Mars at similar temperatures as on Earth.

How do you know that? Just making the atmospheric pressure the same on Mars as on Earth does not make the surface temperature the same. For example Mars has less solar insolation than Earth. CO2 is only 0.038% of Earth's atmosphere not 96% as on Venus (curiously Mars also has about 95% CO2 in its atmosphere). Some Oxygen would be nice too instead of all that CO2

nickname · 2007-03-18 05:49:31

cIclops,

It should be 1-90th Venus temperature divided by 8 for light intensity difference.
or 7.2c average temperature for Mars, Earth is 5c if i remember correctly.

In fact about 2/3 of a bar would suffice, with a 1 bar of co2 Mars would probably be a bit warmer than earth.
Good thing about C02 likes to stay on the planet with little loss from solar activity, so once Mars had a C02 atmosphere it will stay for a long time.
C02 is also a pretty good radiation shield.

With all that C02 we would have lots of 02 available when we need it.
Would be nice to step out on the surface of mars and breathe normally, but i don't think a mainly nitrogen/oxygen Mars atmosphere will stay warm.

cIclops · 2007-03-18 09:44:48

cIclops,
It should be 1-90th Venus temperature divided by 8 for light intensity difference.
or 7.2c average temperature for Mars, Earth is 5c if i remember correctly.
In fact about 2/3 of a bar would suffice, with a 1 bar of co2 Mars would probably be a bit warmer than earth.
Good thing about C02 likes to stay on the planet with little loss from solar activity, so once Mars had a C02 atmosphere it will stay for a long time.
C02 is also a pretty good radiation shield.
With all that C02 we would have lots of 02 available when we need it.
Would be nice to step out on the surface of mars and breathe normally, but i don't think a mainly nitrogen/oxygen Mars atmosphere will stay warm.

The relationship between surface temperature and solar insolation is straightforward, but the effect of an atmosphere complicates things enormously. The average global surface temperature of the earth is about 14 C, Venus is 464 C and Mars is -46 C. Without an atmosphere the earth would be far cooler and so would Venus because of the greenhouse effect. The relationship between temperature and pressure is non linear. It would be better and easier to add water vapor to the atmosphere of Mars, H2O is a stronger greenhouse gas than CO2 and there is lots of it at the South pole.

nickname · 2007-03-18 10:49:25

cIclops,

No doubt the atmosphere would be complicated at Mars.
Adding just 1/4 bar of C02 might be enough to release the frozen water and gasses on Mars.
Those gasses are sure to complicate the picture.

I'm not sure that Earths average surface temperature is 14c?
Most of the surface ocean water is much cooler than this, maybe land temp 14c?

I seem to remember a report that when we take into account the oceans and poles on earth the average surface temperature isn't that far from everything being frozen, just 5c or so.
I could be wrong on that though so don't quote me

Would be sweet if 1/4 bar of C02 could wake Mars up.
I think 1/4 bar is a thing we could do, still pretty big project though.

cIclops · 2007-03-18 11:49:30

cIclops,
No doubt the atmosphere would be complicated at Mars.
Adding just 1/4 bar of C02 might be enough to release the frozen water and gasses on Mars.
Those gasses are sure to complicate the picture.
I'm not sure that Earths average surface temperature is 14c?
Most of the surface ocean water is much cooler than this, maybe land temp 14c?
I seem to remember a report that when we take into account the oceans and poles on earth the average surface temperature isn't that far from everything being frozen, just 5c or so.
I could be wrong on that though so don't quote me
Would be sweet if 1/4 bar of C02 could wake Mars up.
I think 1/4 bar is a thing we could do, still pretty big project though.

So now it's 0.25 bar, yesterday it was 1 bar

It sure would be a big project, but even knowing what to do is way beyond our science, we can only guess what would happen if that much CO2 was added to the thin atmosphere of Mars. The intense debate over the effect of far smaller increases of CO2 in the Earth's atmosphere continues; nobody knows what the effect of that has been or will be. Adding 0.25 bar (1000x more) to the atmosphere of Mars would be a wild experiment.

The average global temp averaged over both land and sea throughout the year, is about 14 C and has been for at least 100 years, before that direct measurements are unreliable. There are many references to this, start with Wikipedia.

nickname · 2007-03-18 12:24:59

cIclops,

1 bar= instant result.
1/4 bar maybe result with mars ingredients.
Stir and wait with 1/4 bar.

I just threw out the 1 bar as a replacement for oxygen/nitrogen atmosphere.

I agree even that 1/4 bar of Venus to mars is a problem.
Not so much the transport to mars, but leaving and collecting at Venus requires Apollo size escape vehicles.

A way does exist to bounce of Venus atmosphere for little escape energies, but collection time is quite small on a bounce of the atmosphere.

Even with a 100 pretty big transports from Venus to Mars and back i would guess at a few 100 years even for 1/4 bar.

nickname · 2007-03-18 13:57:01

cIclops,

Another interesting thing with adding C02 to mars is the melt point of all the frozen items on mars.
Getting Mars warm enough to melt, might mean that when it melts the release of stored frozen water and gas will make it extremely warm, maybe to warm for a long period of time.

As you say it would be a wild experiment, with such slow transport of the 1/4 bar it wont be a real fast experiment and easy to know when to stop import.

It sure is technically feasible to move the co2 to mars from Venus with our technology, but the costs and length of the project and maybe the enduring will to do such a thing would all be astronomical.

I will have to do some research on that 14c earth average temp.
Seems rather high being a canadian *lol*

nickname · 2007-03-18 14:24:45

cIclops,

Found the reason for the difference in temperature.
Mean surface air temperature average 13c.
Mean surface global temperature average 5c

One measuring average ground air temperature 13c, other measuring actual combined ground, ice and ocean water surface temperatures 5c.

I'm amazed they are 8c different, cool temperature of oceans i guess.

cIclops · 2007-03-19 13:53:55

cIclops,
Found the reason for the difference in temperature.
Mean surface air temperature average 13c.
Mean surface global temperature average 5c
One measuring average ground air temperature 13c, other measuring actual combined ground, ice and ocean water surface temperatures 5c.
I'm amazed they are 8c different, cool temperature of oceans i guess.

Rather than simply quote the easy to find Wikipedia value, here is the data from the US National Climatic Data Center

(edited for clarity)
Global Mean Monthly Surface Temperature Estimates for the Base Period 1901 to 2000 (°C)
Land: 8.5
Sea: 16.1
Combined: 13.9

nickname · 2007-03-19 17:04:03

cIclops,

I got a few different results when searching for mean surface temperature of the earth.

The only site i found that combined land, ocean and ice all into one mean temperature was 5c.

Even browsing NASA it wasnt clear how they measured average temperatures and had no mention of including polar ice regions in any equation.

If 13.9 c is the mean temperature of earth, it just means Mars will need more than 1/4 bar of C02 for any hope of getting above the melt point.

C02 isn't the greatest greenhouse gas in the universe anyway, just a convenient one.
1/4 bar of C02 and a small amount of manmade super greenhouse gas might be the formula needed.

cIclops · 2007-03-19 18:00:11

cIclops,
Even browsing NASA it wasnt clear how they measured average temperatures and had no mention of including polar ice regions in any equation.

The global temperature has been measured by satellites for about 30 years, it's quite accurate. Before that it was much more difficult, especially in the polar regions and the oceans, and there are many arguments about the accuracy of the measurements.

nickname · 2007-03-19 19:04:07

That is exactly what i found at many sites.
Most of them had long long arguments about the global earth temperatures.

Lots of the sites quoted best guess
Funny that such a simple thing as figuring out the average temperature is such a complex beast.

I will stick with the 13.9, works for me.

Joseph_Dunphy · 2007-04-08 04:58:01

A thread about the issue of the effect of convection in the Venusian atmosphere as it relates to this topic, located ... here

StarDreamer · 2007-04-28 21:48:25

I value the summing up which launched this thread. That was very good, clear and concise. It brought the problems into sharp focus. We are all so focussed on Mars, yet the Venus cloudtops are looking like our best bet in terms of big results with little effort. I think that any project requiring massive mobilisation of resources right from Day One is going to be doomed to failure or else shall never be begun.

Colonising Mars (nevermind terraforming it) shall demand earthmoving equipment, explosives, smelters, domes, burrowing, heat, power sources, and much else which we just cannot yet do. Mars will demand an off-Earth infrastructure many orders of magnitude greater than what the ISS currently represents. I think Mars is a brutal place.

Venus on the other hand can be colonised without any need for immediate terraforming. People can begin living there a few colonists at a time in small self-sufficient colonies until a tipping point is reached. Terraforming will not, I believe, ultimately be directed from Earth, but shall come about on Venus under guidance from the colonists themselves as a natural evolution from their adaptation to the place. When they are ready, it shall begin, one small step at a time.

Having said that, I don't think we know enough yet about the chemistry of Venus (or Mars either, but I want to focus on Venus). The planet has come to this sad equilibrium for specific reasons. If we are serious about pushing it away from this equilibrium into a new equilibrium (and only an equilibrium will suffice -- constant effort and vigilance is an energy sink), then we have much to learn.

1) If we go the sunshade route, with intent to freeze out the CO2 onto the surface, then there will be no cloud cities. But Venus has no magnetic field, so we could see our remaining atmosphere blown away by a solar flare. :shock: And there is an immense amount of heat trapped in the planet. I would guess it still holds much of the heat of its formation from billions of years ago. Periodically, this heat has resurfaced the entire planet by remelting it. Freezing out the atmosphere would allow this heat to begin an escape. What else might it do? If the weight of atmosphere is compressing the surface, what processes might be unleashed? We might freeze it out, explore the surface, then decide to take the sunshade down again .....

2) The idea of giving Venus a black moon made of elemental carbon is neat. It would contribute to sunshade. But I don't think it would create a magnetic field. Venus lost all its angular momentum in a giant impact late in its formative phase. Earth got overtaken by one of our LaGrange objects, which struck us a glancing blow and birthed Luna (the Moon). This added to our angular momentum because its energy was added to the system. The Moon carried off a lot of surplus silicates from the stratified Earth, thinned our crust and allowed tectonics to persist to the present day, among other things. Venus has a thick crust to trap its heat. Its Lagrange object smashed into it head-on, robbing it of angular momentum (it actually rotates in reverse) and leaving it tidally locked to the Sun. This is the situation which the recently discovered exoplanet Gliese 581c would be in. The tidal friction between Earth and Luna as mediated through our liquid oceans has been dissipating our angular momentum ever since, so that Luna retreats about 10cm every year. Right after Theia's impact, Earth's rotation period was about 5-6 hours, for a year of about 1500 days (same number of hours, you understand, but more days because fewer hours per day). In the preCambrian, our year had about 450 days and perhaps 21-22hrs per day. So if we lift matter off Venus and put it into orbit, the lack of angular momentum should mean this moon could escape Venus orbit very easily, or decay and crash into the surface. It needs torque to keep it all in place, like a gyroscope. I cannot see how we can impart energy into the system without using an impact by an NVA and then the results are potentially chaotic.

3) I think sulphur in the atmosphere is a bigger problem chemically than any other problem addressed so far -- bigger than CO2, for instance. Look up sulphuric acid or vitriol on wikipedia. There is even a section on its role in Venus and how the Sun breaks down CO2 into CO and O2 and then combines that with S to make H2SO4. It ties up all the free hydrogen and oxygen. It destroys water vapour. Plus sulpuric acid will eat any flying vessel we put on the planet. If we can scrub the sulphur out of the atmosphere, then good. But if the planet itself is producing more of it from below, volcanically, then we shall never come to the end of it. Tin appears to be the best metal to combine with it -- you get SnSO4 plus two H2O molecules plus SO2 (sulphur dioxide). Does anyone know of a purely catalytic reaction which will process the sulphur without destroying the raw materials?

4) I think flying cities are out of the question, unless weight proves to be an advantage in staving off hurricane force convection winds or some such thing. Best to disperse resources. I see flying ovoid bubbles with the nature of farms, 3-5 families per bubble, maybe 1km2 each. Solar power, yes, but perhaps with a wind turbine as well, mounted on top like a beanie cap... 8) ... just in case the bubble gets stranded in the doldrums on the dark side of the planet. :shock: The skin of the bubble will be multilayered with water in the layers and the water will be stocked with algae. Venusian atmosphere can be pumped through the water, making a carbonated pond for the algae. The skin of water and algae will filter out a lot of the UV rays and make life inside the bubble friendlier to higher lifeforms -- food crops and small animals. Bubbles may sport lattices of catalytic metals for scrubbing the atmosphere as they go along. This cannot be done too quickly because, even though it is catalytic, the catalyst will get its reactive surfaces clogged up by the byproducts of the reaction. They will need scrubbing. But this can be a cottage industry, along with weaving fullerenes.

5) People have talked about seeding the atmosphere with algae and letting them do the work, but this fails without water or if they sink into the furnace. People have also talked about flying cities in the clouds. How about combining these ideas? Before the flying cities, there must be flying farms. Before the flying farms, let there be flying algae. I think the first step in colonising Venus is to make fullerene capsules, buoyed by Earth air and populated by algae and water. Figure out some way to keep the algae in a friendly environment while bringing Venus CO2 in for them and siphoning off the water and oxygen they produce. It might not even have to be manned.

Bryan

noosfractal · 2007-04-30 01:03:28

Hi Bryan,

Welcome to NewMars.

the Venus cloudtops are looking like our best bet in terms of big results with little effort.

I think it depends on what you mean by "big results." If you're just looking for a second biosphere safely separated from the first by several million miles, I think Venus is in the running, but, from a long term perspective, I wonder how much investment should be made in building at the bottom of yet another gravity well? Once we are free of it, why go back unless there is some really good reason?

What are your solar system development goals Bryan?

StarDreamer · 2007-04-30 06:49:25

I think it depends on what you mean by "big results." If you're just looking for a second biosphere safely separated from the first by several million miles, I think Venus is in the running, but, from a long term perspective, I wonder how much investment should be made in building at the bottom of yet another gravity well? Once we are free of it, why go back unless there is some really good reason?
What are your solar system development goals Bryan?

As a species, as one multicellular lifeform among many in an ecosystem with billions of years of history at our backs, I do not believe that freedom from gravity is a realistic goal. We shall never be able to look back upon this blue dot in space and say Sayonara and make that stick. It may be a means to other ends, but it cannot be an end in itself.

For thousands of years on this Earth, sailors have heard the call of the sea and headed out into uncharted waters in search of new lands, but new land was always the goal. No seafaring people ever took to the sea and stayed there.

Having said that, there shall come a time when Space is thick with our vessels, plying the distances between the orbs of this solar system and perhaps beyond. Some vessels may drop anchor for a time to fish (mine asteroids) upon the high seas, but even they shall return to port.

Gravity wells are a necessary evil. The counterweight to the gravity problem is energy expended in getting in and out of gravity wells. I think a better focus would be on maximising the free energy provided by our Sun to get in and out of the wells and to quicken the transits.

Having said that, I think all the destinations under discussion here are high quality targets -- Venus, Mars, Moon, Europa, Callisto or Ganymede and Titan. Callisto because it is in the Jovian system but free of Jupiter's radiation belts; Ganymede because it has a magnetic field of its own and significant gravity (but still passes through Jupiter's radiation belts); both because they are proximate to Europa but are safer and gravitationally cheaper destinations.

I am trying to break down the problem into its constituent steps, in order to identify the first baby steps. What must come first?

There will be humans on Mars someday, but the climate is brutal, the surface conditions are brutal, the resources are poor -- I do not see where Mars is any more welcoming than the Moon and it is much further away. Look at how many missions to Mars tried to touch down gently and failed; then look at how many missions have relied upon lobbing an object at the surface and using ballistics to land it and succeeded. I think Mars lives up to its name in more ways than one. It is the god of war and we shall tame it only with harsh discipline, if at all.

I came to this site expecting to learn about Mars, but, along the way, in reading the posts here, I have instead fallen in love with Venus. I had never considered oxygen's potential as a lifting gas on Venus. That makes it all so much simpler. We never have to go down to the surface. Going to Venus means coasting in to land on a downy pillow. We can cope with that, as a species. Not every colonist will be a scientist and, even if, there is no guarantee that the offspring of a colony of scientists will match the calibre of the parents. In fact, our future growth off-Earth depends upon "normal" people getting out there. The planet is superabundant in the simple resources that we need to conquer others worlds -- solar energy, wind, oxygen, carbon, ... If Venus has 90atm at the surface and it is 5% nitrogen, then it must have more nitrogen than Earth. The gravity is comparable. People could step out onto the balcony on the cloudcity with an oxygen tank alone and not be concerned about temperatue control or pressure suits.

I think we must settle the Moon before we take on Mars -- airless, low gravity worlds present a certain set of challenges in common and we are not ready for them just yet. The Moon shall allow us to practise these skills close to home. When we get the Moon right, then Mars and Callisto and the asteroids shall be SO much easier. And, as a guiding principle, I firmly believe that we must conquer space with the resources of space. It will be wrong to rob this planet Earth of its resources in terraforming projects elsewhere.

Which brings us again to Venus. Venus has in abundance the resources that we want to take with us to the Moon and to Mars and elsewhere. At 50km up, its surface area is as great as the Earth. The jump from that altitude in and out of space is not as severe as from the surface -- the shuttles expend most of their fuel in that first 50km! Venus is a gift. Mars is hard work.

Again, what is the baby step? Before the cloud cities, there must be colonists and farms. Before the farms, there must be outposts. Before the manned outposts, there must be unmanned platforms and a diversity of self-sustaining experiments.

What would it take to float a fullerene bubble of algae and sulphur-eating bacteria at 50km on Venus? The fullerene bubble would fold up nicely like a parachute. The starter kit of water and algae and bacteria could be shipped in a 5 gallon jug. The floating mixture of air could be compressed in a tank. Send it all to Venus. Drop the bubble into the sky and let it inflate on its way down. Run the water and algae into the fullerene skin layer for maximum exposure to the Sun. The bacteria will convert the sulphuric acid into water and the algae will make oxygen and carbon. Richard Branson could get this much done!

Maybe the very first step is to send Venus a cargo of floating transponders and drop them into the atmosphere to watch how they behave in the winds, a la the movie Twister ...

Bryan

X · 2007-04-30 22:06:24

For thousands of years on this Earth, sailors have heard the call of the sea and headed out into uncharted waters in search of new lands, but new land was always the goal. No seafaring people ever took to the sea and stayed there.

The various groups of sea gypsies used to spend most of their lives at sea, but it does raise an interesting question especially given the below statement.

Again, what is the baby step? Before the cloud cities, there must be colonists and farms. Before the farms, there must be outposts. Before the manned outposts, there must be unmanned platforms and a diversity of self-sustaining experiments.

This site got me to consider Venus much more than I had previously too, but it doesn't seem like much of a place to make a living. How can you extract resources from a place hot enough to melt lead? Farming sounds easy enough, but other than that what can you really do on Venus? The view'd be a lot better than on earth, but there don't seem to be that many people lining up to live on communes now. Is Venus really that much better than space itself?

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