Author Topic: Sun Shade concepts for Venus  (Read 44534 times)

Offline douglas100

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Re: Sun Shade concepts for Venus
« Reply #20 on: 09/16/2011 11:07 PM »

I doubt you can support millions or billions of people in space in the future. Just too complicated. In contrast, Venus is basically Earth's twin sister planet and creative concepts can help with it becoming a more Earth like habitat.

At the end it is the sun shade that makes or breaks the concept of colonizing Venus. As it was said above, if you cool Venus through a sun shade over several decade (according to some estimates over 200 years), CO2 will freeze out of the atmosphere.

Venus is emphatically not Earth's twin. Apart from size it is different in almost every other way. How does cooling it to the temperature of the Martian poles to freeze out the CO2 make it a "more Earth like habitat?"

I find it astonishing that you would call building space habitats "too complicated" compared with the sheer size of the enterprise you are proposing. There is no guarantee whatsoever that Venus can be made remotely Earthlike. Look at the other criticisms in this thread of the idea. There is no reason ever to do it, even if it were possible, which I doubt.



« Last Edit: 09/16/2011 11:09 PM by douglas100 »
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Offline douglas100

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Re: Sun Shade concepts for Venus
« Reply #21 on: 09/16/2011 11:13 PM »

I personally think we will one day learn to live within the small icy bodies of the solar system and forget why we ever thought the ability to stand on the 25% of earth which is not ocean was so important to us.

I think that is far more likely than Venus ever being made habitable.
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Offline colbourne

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Re: Sun Shade concepts for Venus
« Reply #22 on: 09/17/2011 04:54 AM »
Ignoring the ethics of such an act. I would propose a biological terraforming of Venus.
A small seed colony of biological agent could be sent to Venus which will convert the atmosphere to an  inert solid that would sink to the surface thus reducing the planets green house effect.

Offline Nathan

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Re: Sun Shade concepts for Venus
« Reply #23 on: 09/17/2011 05:30 AM »
Venus has the annoying habit of Resurfacing itself every half billion years or so. The place Is designed to sizzle.
« Last Edit: 09/17/2011 05:31 AM by Nathan »
Given finite cash, if we want to go to Mars then we should go to Mars.

Offline AlexCam

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Re: Sun Shade concepts for Venus
« Reply #24 on: 09/17/2011 07:41 AM »

I doubt you can support millions or billions of people in space in the future. Just too complicated. In contrast, Venus is basically Earth's twin sister planet and creative concepts can help with it becoming a more Earth like habitat.

At the end it is the sun shade that makes or breaks the concept of colonizing Venus. As it was said above, if you cool Venus through a sun shade over several decade (according to some estimates over 200 years), CO2 will freeze out of the atmosphere.

Venus is emphatically not Earth's twin. Apart from size it is different in almost every other way. How does cooling it to the temperature of the Martian poles to freeze out the CO2 make it a "more Earth like habitat?"

I find it astonishing that you would call building space habitats "too complicated" compared with the sheer size of the enterprise you are proposing. There is no guarantee whatsoever that Venus can be made remotely Earthlike. Look at the other criticisms in this thread of the idea. There is no reason ever to do it, even if it were possible, which I doubt.

Most of what have been brought up in this thread as showstoppers is either undefined or incorrect. Some say it is too costly, without specifying why. Some say heavy volcanic activity is a problem without specifying the time frame of this activity (every few hundred thousand years, isn't a problem). Some talk about the lack of a magnetic field, failing to say why that would be a problem. Some talk about the lack of hydrogen or water, failing to say that there is enough of both to support a large human colony for thousands of years, although there is not enough to support oceans or lakes. Etc.

An interesting articles detailing the challenges and concepts required is e.g. laid out here http://www.paulbirch.net/TerraformingVenusQuickly.pdf

To sum up, if it were possible to inject self-replicating sun-shading particles in the upper atmosphere of Venus that cool the planet in the time frame (a few dozen years) people have suggested for all the CO2 to fall as snow, Venus would be by far the most benign environment for humans in the solar system outside Earth.

Offline douglas100

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Re: Sun Shade concepts for Venus
« Reply #25 on: 09/17/2011 11:34 AM »

 Some say it is too costly, without specifying why. 

Some say it is affordable without specifying why.

Birch's paper is interesting. (I wish the BIS would put back issues of JBIS online, but that's another issue.) But the environment he ends up with still needs managing on a huge scale to keep it habitable.

The thing we have learned from exploration of the Solar System is how little we understand about planetary environments. There are too many unknowns to predict the outcome of modifying a planet like this.

You didn't reply to my point about about space habitats, the one that you dismissed as "too complicated." (Compared with terraforming a planet-are you serious?) The reason I raised the point is because the real showstopper for this proposal in reality is: why do it at all?
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Offline gospacex

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Re: Sun Shade concepts for Venus
« Reply #26 on: 09/17/2011 01:05 PM »
When I fired this sunshade idea at Adam Crowl his maths suggested the atmosphere taking between 2 and 90 years to freeze out with a geometric mean of ~13 years. Not a very long wait for that much real estate.

Something is seriously off with that math.

Icelandic lava flows about 20 meters thick took decades to cool down. Icelanders were even using them to generate electricity.

Venusian atmosphere is equivalent to a kilometer-thick layer of water by mass. I have hard time imagining that cooling down from hundreds of degrees Celsuis to -78 C in 13 years, much less in 2 years.

Offline JohnFornaro

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Re: Sun Shade concepts for Venus
« Reply #27 on: 09/17/2011 02:14 PM »
Most of what have been brought up in this thread as showstoppers is either undefined or incorrect. Some say it is too costly, without specifying why.

You're saying it's not too costly?  Call me Buzz Killington, if you will.   
Sometimes I just flat out don't get it.

Offline pippin

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Re: Sun Shade concepts for Venus
« Reply #28 on: 09/17/2011 02:22 PM »
When I fired this sunshade idea at Adam Crowl his maths suggested the atmosphere taking between 2 and 90 years to freeze out with a geometric mean of ~13 years. Not a very long wait for that much real estate.

Something is seriously off with that math.

Icelandic lava flows about 20 meters thick took decades to cool down. Icelanders were even using them to generate electricity.

Venusian atmosphere is equivalent to a kilometer-thick layer of water by mass. I have hard time imagining that cooling down from hundreds of degrees Celsuis to -78 C in 13 years, much less in 2 years.
Especially since all the heat needs to be radiated. No melting snow, wind or water to cool things down.

Offline aero

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Re: Sun Shade concepts for Venus
« Reply #29 on: 09/17/2011 04:20 PM »
No one has mentioned that the interior of Venus is very hot. It is a huge, (81.5% of Earth's mass) very hot rock with high internal temperatures. It may or may not have a liquid core but the rock is big enough and hot enough that heat inertia (if that is a concept) will keep the atmosphere gaseous for a very long time.
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Offline Andrew_W

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Re: Sun Shade concepts for Venus
« Reply #30 on: 09/17/2011 05:11 PM »
When I fired this sunshade idea at Adam Crowl his maths suggested the atmosphere taking between 2 and 90 years to freeze out with a geometric mean of ~13 years. Not a very long wait for that much real estate.

Something is seriously off with that math.

Icelandic lava flows about 20 meters thick took decades to cool down. Icelanders were even using them to generate electricity.

Venusian atmosphere is equivalent to a kilometer-thick layer of water by mass. I have hard time imagining that cooling down from hundreds of degrees Celsuis to -78 C in 13 years, much less in 2 years.

Rock and soil are pretty good thermal insulators, air is not.

On Earth the lower atmosphere will cool by something like one degree C an hour through the night, on Venus we have 100 times the atmosphere and want to cool it by ~600C, so if we lose 0.01C/hr it would take 60000 hours - about 7 years, and because it's starting from a higher initial temperature the initial rate of heat loss would be pretty high.

No one has mentioned that the interior of Venus is very hot. It is a huge, (81.5% of Earth's mass) very hot rock with high internal temperatures. It may or may not have a liquid core but the rock is big enough and hot enough that heat inertia (if that is a concept) will keep the atmosphere gaseous for a very long time.

As I said above, rock is a pretty good insulator (you can walk bare foot over lava that's still at hundreds of degrees just a few inches inside, it would only be the upper most few meters of the crust that would feed heat to the atmosphere at a significant rate. Your hot crust point is relevant though to any CO2 icecap, as such an icecap would also be a good insulator.
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Offline Andrew_W

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Re: Sun Shade concepts for Venus
« Reply #31 on: 09/17/2011 08:30 PM »
The discussion I had with Adam is here:
http://crowlspace.com/?page_id=170

My own BOE maths suggests that it'd take at least a century and a half for Venus to lose enough heat (working on the current heat loss rate of ~150W/m^2 (the disk receives about 2.5kw/m^2, high albedo means it absorbs only about 25%, and that's what it loses since it's in thermal equilibrium, and surface area is 4 times the size of the disc) common sense would suggest the the current rate of heat lose would fall as the planet cooled, but I could see how vertical movement of air could be enhanced, thus bringing more warm air to TOA and actually accelerating the rate of heat loss.
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Offline savuporo

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Re: Sun Shade concepts for Venus
« Reply #32 on: 09/18/2011 04:57 AM »
You didn't reply to my point about about space habitats, the one that you dismissed as "too complicated." (Compared with terraforming a planet-are you serious?) The reason I raised the point is because the real showstopper for this proposal in reality is: why do it at all?
I think you are missing a basic trait of humans here. Regardless of if its sensible, expensive, realistic or anything else, once the capability exists, it WILL be tried.
Yes, most may choose to stay in space based habitats, but everything else will most likely be tried in some shape or form as well. There will be people insisting on trying to make Mercury livable.
Quite as some people insist on living in Rovaniemi, Finland.

In other words, IMO O'Neill habitats and Mars colonization are off topic for this thread.

Also i do not think manufacturing atmospheric sunshades for the entire planet is too far fetched, with partially self-replicating macroscale machinery, which is real technology even now.
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Offline aquanaut99

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Re: Sun Shade concepts for Venus
« Reply #33 on: 09/18/2011 06:05 AM »
You didn't reply to my point about about space habitats, the one that you dismissed as "too complicated." (Compared with terraforming a planet-are you serious?) The reason I raised the point is because the real showstopper for this proposal in reality is: why do it at all?
I think you are missing a basic trait of humans here. Regardless of if its sensible, expensive, realistic or anything else, once the capability exists, it WILL be tried.

No. Bad argument. I predict that if humanity survives this century, that trait will die. There is such a thing as a precautionary principle, you know. One should not do everything that one could. That's why we didn't nuke ourselves to kingdom come during the Cold War (we flew to the moon instead).

Quote
Quite as some people insist on living in Rovaniemi, Finland.

So? That's a nice enough place to live (all you need is some warm clothing for winter). Venus is not.

« Last Edit: 09/18/2011 06:05 AM by aquanaut99 »

Offline cro-magnon gramps

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Re: Sun Shade concepts for Venus
« Reply #34 on: 09/18/2011 08:02 AM »

Anyway, this seems like a reasonable engineering project, given a suitable timescale (200,000 years) and budget for getting it going (a significant proportion of Earth's Gross Planetary Product).

what of the SGPSP of 2200 ;) or Sol's Gross Planetary System Product; ok, we are talking Sci-Fi, but so is Terra Forming a planet; (bwt it is 3:48am so a good time to think of such things ;)
   Technical problems aside, there is nothing wrong in the concept, other than the moral one, if there is life forms on Venus; it is probably not going to be known for a few years, but if a CO2 based life form exists in Venus' atmosphere, then you may have a problem;
    but even putting that aside, it would take the resources  of a Class 1 at 1.10 % to even begin to work on something this big; perhaps it is appropriate that as a Class 0 society at 0.7 % we are even thinking it;
     good luck with your ideas;

Gramps

ps remember discussing this in the late 60's early 70's, with a bunch of Marxist Lenist University Students, over a carafe of red wine and pizza, while others played pong at another table with the screen built into the table ;-) now project your selves 40 years, to 2050 and think about this again!!?? imagine how technology and society will have changed LOL perhaps it doesn't sound so outrageous ;)
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Offline AlexCam

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Re: Sun Shade concepts for Venus
« Reply #35 on: 09/18/2011 08:15 AM »
Most of what have been brought up in this thread as showstoppers is either undefined or incorrect. Some say it is too costly, without specifying why.

You're saying it's not too costly?  Call me Buzz Killington, if you will.   

If we were able to create macroscopic robotic elements or biological elements that can be self-replicating and contain little sun-shades, that can be seeded in the upper atmosphere of Venus, then the actual costs of flying a mission there to start the sun shading will cost about as much as Venus Express. There is no need to do anything except deploy the first initial elements and let them take it from there.

Offline savuporo

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Re: Sun Shade concepts for Venus
« Reply #36 on: 09/18/2011 07:47 PM »
I think you are missing a basic trait of humans here. Regardless of if its sensible, expensive, realistic or anything else, once the capability exists, it WILL be tried.

No. Bad argument. I predict that if humanity survives this century, that trait will die.

The last sentence is an oxymoron. I'll let you figure out why.


Quote
Quote
Quite as some people insist on living in Rovaniemi, Finland.

So? That's a nice enough place to live (all you need is some warm clothing for winter). Venus is not.
One man's hell is another man's paradise, yes.

Enough with off topic though.
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Offline savuporo

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Re: Sun Shade concepts for Venus
« Reply #37 on: 09/18/2011 07:55 PM »
If we were able to create macroscopic robotic elements or biological elements that can be self-replicating and contain little sun-shades, that can be seeded in the upper atmosphere of Venus, then the actual costs of flying a mission there to start the sun shading will cost about as much as Venus Express. There is no need to do anything except deploy the first initial elements and let them take it from there.

The problem here is that fully self replicating machinery may be very far off, but partial self-replication is achievable even now, see RepRap

Fabricating things like ICs currently just require a ton of infrastructure, and there are no good substitutes for something as simple as an 8-bit MCU that could easily be fabbed, although there are some avenues of research going on there.

Fortunately the hard to fab parts are relatively lightweight by mass, which would reduce the shipped mass requirements for terraforming scale projects from totally insane to moderately bonkers.
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Offline AlexCam

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Re: Sun Shade concepts for Venus
« Reply #38 on: 09/19/2011 05:08 PM »
If we were able to create macroscopic robotic elements or biological elements that can be self-replicating and contain little sun-shades, that can be seeded in the upper atmosphere of Venus, then the actual costs of flying a mission there to start the sun shading will cost about as much as Venus Express. There is no need to do anything except deploy the first initial elements and let them take it from there.

The problem here is that fully self replicating machinery may be very far off, but partial self-replication is achievable even now, see RepRap

Fabricating things like ICs currently just require a ton of infrastructure, and there are no good substitutes for something as simple as an 8-bit MCU that could easily be fabbed, although there are some avenues of research going on there.

Fortunately the hard to fab parts are relatively lightweight by mass, which would reduce the shipped mass requirements for terraforming scale projects from totally insane to moderately bonkers.

Organic material can self replicate. There have been suggestions of seeding genetically modified algae into the Venusian atmosphere.

Offline savuporo

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Re: Sun Shade concepts for Venus
« Reply #39 on: 09/19/2011 05:53 PM »
Organic material can self replicate.
Yes, i have experienced it :)
Quote
There have been suggestions of seeding genetically modified algae into the Venusian atmosphere.
Sure, and it would be fantastic if this could be worked out. Im somewhat skeptical that our genetic engineering is advanced enough or has well understood long term effects and is controllable enough to attempt something like that.
Seeing the rapid developments in the field this may well be a viable option once the question of terraforming becomes relevant.
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