Terraforming with a Broom

C M Edwards · 2007-04-04 11:43:05

A recent study of Mars's albedo concludes that the planet's albedo has been decreased by windblown dust over the past 30 years, causing a slight increase in its average temperature.

In areas where subsurface dust layers tend to be darker, it might be practical to gain a slight increase in temperature for large regions simply by sweeping off the upper layer of dust and letting the wind scatter the lower layers further afield. Addition of a colorant - such as carbon black - would further decrease the average albedo of the dust, leading to a greater temperature change.

The amount of soil that would need to be removed for a 1 degree celsius change could be relatively small in volume, as would the amount of carbon black dust required for the same change.

nickname · 2007-04-04 14:35:23

C M Edwards,

I had a similar idea for Mars a while back, but in involved mining phobos surface for the dark material that is covering phobos a few meters deep.
Pretty easy to deliver it to Mars and let the atmosphere spread it for you.

Not sure even if you cover all of mars with a thin black layer it will warm Mars enough for any melt.
Black surface in conjunction with a small kb ice asteroid impact, then maybe easy partial change of Mars to at least the melt point.

Simple usually works best.

X · 2007-04-04 20:04:24

Why not just roll out some black blankets or plastic? Like the fabric or plastic folks put under landscaping to keep other plants from growing maybe. Just put some big rocks around the edge to keep it from blowing away.

C M Edwards · 2007-04-05 15:30:49

Why not just roll out some black blankets or plastic? Like the fabric or plastic folks put under landscaping to keep other plants from growing maybe. Just put some big rocks around the edge to keep it from blowing away.

Ah, but we would want it to blow away.

The virtue of carbon black is that it can be manufactured from carbon dioxide and it can be powdered enough to be windborn. It's also fairly innocuous. Having the low albedo agent blown on the wind seems to be a fairly efficient means of delivery.

nickname · 2007-04-05 18:16:16

C M Edwards,

The idea of a black Mars has big potential.
I personally think dark dust in combination with either a small water ice impactor or super greenhouse gas manufactured on Mars is a winning formula.
The later two are both semi low tech, semi easy to do and allow colonists to be living on the planet at the same time.

If phobos is as black and dusty as they predict, it should be enough material sent from phobos to the surface of Mars to at least double or triple the heat retention (guess), even mixed in with the native dust.

I like the idea of moving soil to expose dark material, pretty easy at that point to darken it further.
Still a big project to move enough to make an impact on temperature globally.

Good idea again CM, lets get some big brains on this and tweak it with some math.

RickSmith · 2007-04-07 03:42:15

C M Edwards,
I had a similar idea for Mars a while back, but in involved mining phobos surface for the dark material that is covering phobos a few meters deep. Pretty easy to deliver it to Mars and let the atmosphere spread it for you.
Not sure even if you cover all of mars with a thin black layer it will warm Mars enough for any melt. Black surface in conjunction with a small kb ice asteroid impact, then maybe easy partial change of Mars to at least the melt point.
Simple usually works best.

Hi nickname, C M Edwards, everyone.
Your idea got me curious. Is there enough mass on Phobos to do the job? Let us say that we grind Phobos completely into dark dust. We likely need a thickness of at least a millimeter of dust to significantly darken Mars' surface. What is the mass of a mm of dust?

Let us see, if we assume that it masses the same as carbon, then one gram of carbon masses (graphite) ranges from 1.9 to 2.3 g/cm3. (I'll pick the lower value.) 1mm x 1cm x1cm is 1/10 of the volume of cubic cm, so this means that the mass will be 0.19 g/cm^2 (to cover a square cm of Mars). There are 10,000 square centimeters in a square meter so this becomes 1900 g or 1.9 kg of dust to cover a sqare meter 1 mm deep.

Is the assumption that Phobos has the same mass as carbon a good guess? Phobos is thought to be a Carbonaceous Chondrite which are made up of: "carbon in the form of poorly crystallized graphite, fine-grained clay minerals, organic polymers, magnetite and iron sulfide." (They also have other volitiles that have burned off when they fall to Earth.) Their density is about 2.2 g/cm^3. (Other Chondrite meteors have densites of around 3.6 g/cm^3.)

Compare this to Phobos which has a mean density of ~1.9 g/cm^3 (which makes sense as its volitiles have not burnt off as they fall thru the Earth's atmosphere.) However if drop powdered Phobos on Mars those volitiles will be baked off in the atmosphere and on impact. So rather than using pure carbon, it would likely be safer to use the 2.2 g/cm^3 density for Carbonaceous Chondrite meteors.

This means that we need 2.2 kg per square meter of Mars.

I will further assume that Mars is a perfect sphere. This gives it an area of:

surface area = 4 PI r^2 = 4 * 3.1415 * 3,398,000^2 = 1.45 E 14 square meters.

So we will need 3.19 E 14 kg of dust to cover Mars this way.

Phobos has a mass of 9.6 E 15 kg however, the volitiles will be lost which (looking at the ratios of Phobos to Carbonaceous Chondrites) would be about 15% loss. Even so, there is enough mass in Phobos to cover Mars to a depth of about a 5 cm. Phobos has a radius of (very roughly) 140 km. Dividing this radius by 50 means that we would need the top 2.8 km of Phobos to cover Mars to 1 mm depth.

*********************************************************************
EDIT: Joseph_Dunphy noticed an error above. Phobos is 27 by 22 by 18 kilometers not 140 km I use above. (I mis-read the table.) He sent me a correction off line so as to not embarrass me. What a nice guy!!! Averaging this is very roughly a radius of 22 & 1/3 km. Dividing THIS number by 50 means that we will need about 445 meters of soil.

Many thanks Joseph for pointing out my mistake.
**********************************************************************

So we will need a lot more than the top few meters of Phobos to do the job, but in principle it is totally possible.

Now Mars' regular dust will blow about and this new dust will get concentrated in areas or covered up in others. So we might well want to us a lot more than just 1 mm as a safety margin.

Mars has an albedo of 0.15 and Phobos has an albedo of 0.05. (The closer to zero the albedo is the closer to totally black it is.) I'm out of time so in another post I will calculate the black body temperature of Mars if we turn it as black as Phobos.

The size of Mars & Phobos as well as info on Carbonaceous Chondrites was from "Moons & Planets 3rd Edition" by W. Hartmann.

Warm regards, Rick.

nickname · 2007-04-07 12:21:00

RickSmith,

Thanks for the input on this.
You must be that bigger brain i was talking about.

I think dark Mars has potential, wasn't expecting to need so much of Phobos.
Might be a good and bad thing though about needing more of Phobos.
Having to grind up Phobos will probably allow us to collect the ingredients needed for super greenhouse gas at the same time.

Can't wait to see the Mars temperature difference at near Phobos color.
Any data of how warm the surface of Phobos gets?
That would give us a decent clue, if i can find it.

nickname · 2007-04-07 12:32:06

Rick,

Found this....

Measurements of the day and night sides of Phobos show such extreme temperature variations that the sunlit side of the moon rivals a pleasant winter day in Chicago, while only a few kilometers away, on the dark side of the moon, the climate is more harsh than a night in Antarctica. High temperatures for Phobos were measured at -4 degrees Celsius (25 degrees Fahrenheit) and lows at -112 Celsius (-170 degrees Fahrenheit). This intense heat loss is likely a result of the fine dust on Phobos' surface, unable to retain heat.

At this site. http://sse.jpl.nasa.gov/planets/profile … Mar_Phobos

Seems a black Mars might be much closer to the melt point than i first expected.

RickSmith · 2007-04-08 00:42:11

RickSmith,
Thanks for the input on this.

Hi nickname,
Feel free to call me Rick if you like. Thanks for the kind words.

The equation for a black body (a body that glows only because of its temperature) is:

T = 4th_root of[ ( Insolation * 1 - Albedo) / (4 * Boltzmann Constant ) ]

Where the Boltzmann constant is 5.67 E -8 W / m^2 K^4

(Where K is degrees Kelvin.)

Mars is a near vacuum so this formula will be pretty close to the real values.

Temperature of Mars Now (albedo of 0.15):
T = ( 560 watts / m^2 * ( 1 - 0.15 ) / (4 * 5.67 E -8 W / m^2 K^4 )) ^1/4
= ( 2.1 E 9 K ^ 4 ) ^1/4
= 214 K which is equal to -58 C

// My references say that Mars has an average temperature of -63 C so this would suggest that its thin atmosphere has a greenhouse effect of 5 C. Another text I have says that the Martian greenhouse is 3 C. So we are all in the right neighborhood but may be off by a degree or two in these calculations. (Or we are dead on and my text is off by a couple of degrees...)

Temperature of Mars with Powdered Phobos on it. (albedo of 0.05)
T = ( 560 watts / m^2) * (1 - 0.05 ) / ( 4 * 5.67 E -8 W / m^2 K^4 )) ^1/4
= ( 2.346 E 9 K ^ 4 ) ^1/4
= 220 K which is about equal to -53 C.

So changing the albedo from 0.15 to 0.05 will add 5 degrees onto the temperature of Mars. This may not sound like much, but it is what Robert Zubrin suggested was needed to evaporate the CO2 on the south pole and start the terraforming process.

Just for fun I calculated the black body temperature for Earth and Venus.
(Assuming an insolation of 1300 W/m^2 for Earth and an albedo of 0.32.
Assuming an insolation of 2487 W/m^2 for Venus with an albedo of 0.59.)

Black body Temperature of Earth. = 249 K or -23 C
Black body Temperature of Venus = 283 K or 11 C

Observed Temperature of Earth. = 15 C
Observed Temperature of Venus = 737 K or 464 C

Thus the Earth's greenhouse is giving us a 38 C boost in temperature.
On Venus the greenhouse boost is 453 C.

REFERENCES:

// A nice discussion of the mathematics for Albedo can be found here.
http://www.lwr.kth.se/Grundutbildning/1 … 02s01.html

// I also used "Moons & Planets 3rd Edition" for basic astronomical facts.

Warm regards, Rick.

nickname · 2007-04-08 05:48:16

Rick,

Your welcome

Very interesting.
I was expecting only 2 or 3c with a limited possibility of C02 melting.

5c would have a runaway effect on Mars, it should melt enough C02 to contribute quite a bit of weight to the atmosphere.

If the poles are indeed a lot of C02 and especially lots of frozen C02 in the equatorial regions, then just making Mars black this way might start the terra form process rolling.

If we can produce enough super greenhouse gas from Phobos at the same time, we probably have a simple scheme to alter Mars much closer to Earth.

Interesting to see what a black earth would be like also, i think we are doing that without intention

nickname · 2007-04-08 08:20:35

Rick,

Just had a second look at this....

Thus the Earth's greenhouse is giving us a 38 C boost in temperature.
On Venus the greenhouse boost is 453 C.

Had an interesting thought here, it's a bit off topic but wanted to get it in type before i forgot.:)

I bet if we did some math on the co2 earth quantity vs Venus and sunlight differences the co2 isn't warming Venus enough to account for Venus temperature.

Might be an interesting calculation to see what the co2 is really doing for temperature on earth and Venus as we have solid temperature data for both.
With a little rough math in my head with just co2 differences and bar difference and light difference.
Venus should be much warmer if co2 heat retention theory is correct, or the earth should be cooler?
We could probably get data from Mars as well as we know it's co2 and temperature.

Somethings not right in general co2 theory somewhere.
Interesting.

RickSmith · 2007-04-09 01:26:04

Rick,
Somethings not right in general co2 theory somewhere.
Interesting.

Hi nickname.

I have not said that all of the Earth's greenhouse warming is caused by CO2. It is caused by many other gases, including water, NO2, CH4, NH3, etc. Venus is more clear; it has a 90+ bar atmosphere of CO2 with a touch of sulfuric acid tossed in.

It is inarguable that Venus and Earth are hotter than their blackbody temperature because of the 'greenhouse' warming caused by their atmospheres.

(Greenhouse is in quotes above because the mechanisms of atmospheric warming is not 100 percent like greenhouses. For one thing, a major part of terrestrial greenhouses warming ability, is preventing a breeze from blowing the warm air away from the plants. However as an analogy it is not too bad and everyone calls it greenhouse warming so I won't use further quotes when referring to this effect of atmospheres on planets.)

If you want to post that the greenhouse effect is some kind of weird myth, I suggest you post in the "Is Global Warming Real" thread. This topic is discussing how much Mars would warm up if we powdered Phobos.

If we treat Mars as a black body, the answer is not very much. Obviously not worth the effort. However, the point of most of the terraforming strategies is that there IS a real benefit to thickening the atmosphere. Planets with atmospheres are obviously warmer than those without.

For an explanation of how thickening Mars CO2 atmosphere will warm the planet, you might want to read: "The Case For Mars: The Plan to Settle the Red Planet & Why We Must" by Robert Zubrin.

Regards, Rick

nickname · 2007-04-09 06:30:50

RickSmith,

Wasn't questioning your numbers, was just questioning the numbers for C02 greenhouse effect on 3 different places with 3 different atmospheres.
Even with all the differences in Venus Mars and Earth the C02 math is not adding up.

You are right of course it's not the place to put it, but wanted it somewhere so i can go check and not forget.
Just a hunch but i think general C02 is wrong.
Math time for me before i post on it

nickname · 2007-04-09 06:37:28

Mars as a black body is only worth the effort if it contains enough super greenhouse gas components also.

Getting Mars past the C02 melt and past the H20 melt are two very different things unless almost all of the poles are C02.
Data so far doesn't support that.

Interesting though that using a moon destined to crash on the surface of Mars might be a good step forward to a warmer place.

I wonder what Deimos offers?

SpaceNut · 2007-04-09 20:08:35

This change in temperature as a function of color is a real Dah, even kids in middle school know that colored sheets of paper obsorb differing amounts of energy to melt an ice on it at a different rate of time. Just look to the roofs of your homes in your area. In hot areas they are light colored for a reason and in the far north they will be mostly dark.
Heat transfer from a dark surface does not extend very far from the surface into the atmosphere in the open and while CO2 is a better greenhouse gas it would only extent the height above the surface only slightly.
I would rather like to know how the obsorbed energy is transferred into the soils with regards to depth to temperature with respect to color.

RickSmith · 2007-04-10 17:38:29

If the poles are indeed a lot of C02 and especially lots of frozen C02 in the equatorial regions, ...

Hi nickname,
It is far too warm for solid CO2 to form at the Martian equator. It can only form at the poles in winter (when the sun never rises for several Earth months at a time).

I was going to recommend a good primer in astronomy and planetology but I don't know of any. (I have a dozen books but they are all advanced.) Does anyone know of a good basic astronomy book that gives a fair bit of information on Mars?

Warm regards, Rick.

nickname · 2007-04-10 19:05:36

Rick,

Please! don't.

Don't try to treat me like a dummy.
I don't care if you are generally a rude and condescending person like you have been in many posts that i have simply just overlooked.
That isn't a theory, it's fact.

I have read more books than i care to shake a stick at.
I can make my own theory on my own thoughts without reading more unproven theory.

When i have an idea it's original, something you should think about being.
I can't suggest any book to prime for this, it's to advanced to put in book format.
How is that for rude and condescending?

One to many posts with little funny remarks Rick

RickSmith · 2007-04-10 19:54:12

Hi nickname,
Sorry if I came across as condensending. I didn't realize you were telling a joke when you said that lots of solid CO2 was on the equator of Mars.

This is a forum to discuss scientific topics and I am frequently saddened by how poorly educated most people seem to be on scientific topics. I having been putting some effort into correcting a lot of errors. Just part of my service to the community.

I may come across as being condesending. Hell, I probably am condesending, when people, in all seriousness, start talking about moving planets around like billard balls & the like. But I don't believe I have been rude. I go to great effort to remain polite even when people say things I personally find offensive and stupid.

If you have read some good books on Terraforming, perhaps you could write a review in the thread I created for that?

In any case, I appologize.

I still would like to know of a good introductory book on astronomy and Mars. Anyone know of any?

Warm regards, Rick.

nickname · 2007-04-10 20:16:05

Rick,

Sorry for blurting out.
Bad day at work and bad wife at home LOL

I didn't say solid C02 was on the equator.
I did say that C02 mixed with H20 as a geyser might be a reason for a liquid on the surface.
Solid C02 is probably on the equator also but well beneath ground, you didn't hear that from me though.

We just don't know enough about Mars to make any real educated guesses.
I just throw out ideas to see if they get chewed up , if they are not realistic it becomes pretty apparent pretty fast.
Nothing wrong with the process though.
No hope of me ever thinking inside the box, way to dark in there for me

No prob Rick, and sorry again.
Typed words have a way of coming across blunt and sometimes not exactly what we meant to say.

RickSmith · 2007-04-10 20:26:51

Rick,
Sorry for blurting out.
Bad day at work and bad wife at home LOL ....
... Solid C02 is probably on the equator also but well beneath ground, you didn't hear that from me though.

Hi nickname,
No problem. Yes it is easy to come across the wrong way in email and on forums. I should try to use more smilies...

I doubt that we will find solid CO2 under ground on Mars' equator. The thing is that the temperature goes up because Mars has been volcanically active in the last 250 million years in many areas on the planet. This means that there is a lot of ground heat, so temperatures will go up as you go deeper.

However I expect that there are CO2 deposits underground at the equator: both dissolved in water & in ice as clathrates. Liquid CO2, held at pressure under a H2O cap, is possible tho more likely in regions nearer the poles.

Warm regards, Rick.

RickSmith · 2007-04-10 21:59:57

...
I would rather like to know how the obsorbed energy is transferred into the soils with regards to depth to temperature with respect to color.

Hi Space Nut,
We have been measuring how quickly the permafrost is melting in the Canadian arctic and what has been found is that the top layers of soil warm fairly quickly, but the deeper you go, the slower the 'wave of warmth' travels.

In "The Case for Mars", Robert Zubrin says that this warming is a square relation. On page 262, he shows the rate that the warming soil will outgas CO2. (He assumes that the soil is being warmed by solletas and by CO2 already released by evaporting the CO2 polar cap.)

I copy a few lines of his table here:

Time...............................Depth...........................Atmosphere
(Earth.............................Penetrated....................Created
Years).............................(meters)........................(millibars)
--------------------------------------------------------------------------------------------
1..........................................04...................................20
4..........................................08...................................40
9..........................................12...................................60
16........................................20..................................100

100......................................48..................................200

400......................................80..................................240

So the answer to your question is that any heat caused by darkening Mars will eventually reach great depths providing it goes on long enough.

If we warm the atmosphere of Mars, it will take a long time for the full effects to be felt but given time it will happen.

I don't know how accurate his estimated pressures will be. Are clay minerals (that best absorb CO2) common 80 meters below the surface? If these minerals are under pressure, do they absorb CO2 as well? On the other hand, he does not take into account CO2 clathrates or dissolved CO2 in aquifers so his estimate may be too low.

Warm regards, Rick.

SpaceNut · 2007-04-11 07:16:59

Thanks for the response Rick at this time I do not own a copy of the "The Case for Mars", by Robert Zubrin but it sound like it is full of good stuff. At this time I am unable to purchase such extras but maybe in the future. Oh, just so that you know I am just an average joe and not an engineer of the science fields... but that does not stop me from asking questions and learning as I go.

nickname · 2007-04-11 14:27:49

SpaceNut,

A science degree is usually way over rated anyway and does not make you more of a scientist, maybe just a more limited scientist.

Only original thinking does that, something that no school will ever be able to teach.

Think of it this way, no one is paying you to think anything, you have no career to worry about being tarnished.
You do not need to agree with anything because your paycheck depends on it.
Maybe you are a better scientist as a ordinary Joe than you ever could have been with a piece of paper stating such.

I'm happy to be a Joe also

RickSmith · 2007-11-21 05:07:37

I had a thought. Let us say that you get a Carbonaceous Chondrite (CC) asteroid to build a soletta with. A CC asteroid is the most common sort and has plenty of clay minerals for aluminum and carbon and hydrogen for plastic.

Assuming the soletta has a mass of 200,000 tonnes (estimate from Case for Mars) then a 1 km radius asteroid should have enough aluminum to build this with a healthy amount left over. The CC that is left could be dropped on the south pole to multiply about 19 fold the effectiveness of the heat being beamed onto white ice.

The area of the south polar cap is roughly 500,000 km^2. From my calculations before we need 2.2 kg of dust per square meter. So we will need 5E11 kg or 5E8 tonnes.

Each cubic meter of CC is 2200kg so we will need 2.3E8 cubic meters. This is a block about 615 meters on a side. This is about ~1/40 the volume of our initial rock.

So if we assume that the Martians build their own soletta, (rather than flying it from Earth on the solar wind), then they should have enough left over from a 1 km rock to dust the polar cap. This will have a huge impact on how quickly the south pole heats up. Waste not, want not.

Warm regards, Rick.

nickname · 2007-11-21 07:38:53

RickSmith,

This is kind of my latest thinking for warming Mars doing something similar to what you describe but using a very simple source of carbonaceous material.

We have a very good source of carbon on Phobos in dust format already.
We can use that dust in a better way than just spreading it out on the poles.

If we simply scrape of the dust of phobos and compress it into small packages then launch them towards either pole.
Tiny escape velocities for this, a small solar powered magnetic launcher would work.

We get the blackness of the non reacted carbon, the heat from impacts, the creation of lots of new c02 from water ice conversion, methane, water vapor, oxygen, nitrogen and other trace gasses trapped in the ice.

Phobos is expected to have a few meters of carbon soot on its surface so more than enough just lying around to melt and react both poles completely.

I've been trying to crunch the numbers of the pole ice amounts on Mars.
So far this is the best i can do with available info on ice quantity and makeup on Mars and carbon dust quantity on phobos.

Lots of educated guesses here.

With impactors of Phobos carbon dust bullets we get around 100mb of new co2, 2 mb of methane, 10 mb of oxygen and 10-20mb of free hydrogen.
We will probably get .5mb of trapped nitrogen from the ice and a host of other trapped trace gasses for another .5mb.

I think 110-130 mb of mostly c02 with 1-2% methane should completely melt the rest of mars.
It bypasses the Mars ice ball scenario also as the temperature would rise very fast.
110-130mb is before the rest of Mars begins to melt.

Let me know what you think Rick.
It's real low tech, technically within our means to do in pretty short time spans.

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Re: Terraforming with a Broom

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