Nested Sphere around Venus

Antius · 2016-05-05 13:47:07

Building a shell around a planet 8000 miles wide is a task of mythic proportions. Thousands of trillions of tonnes of material - millions of cubic miles of whatever you end up using. In comparison, a sun orbital mirror would weight a few billion tonnes. It is therefore at least a million times less massive than any realistic shell. And you build it in space and not a toxic atmosphere. It is still a massive task - orders of magnitude more massive than the most massive structure ever produced by man. But at least foreseeable at capability levels that we are likely to have in the next few centuries. I guess I am looking for ways of transforming Venus into something useful that are remotely achievable using real-tech. I dont think these discussions are worth anything unless there are real ways of achieving them.

It is hard to imagine any large scale human presence on Venus until surface conditions are more habitable. That means tolerable temperatures and pressures that allow people to breath nitrogen based air without narcosis. Not necessarily breathable air on the surface, but less than crushing pressures. Once that is achieved you can start building habitats using surface materials and incrementally extend them over the planet. Take that process far enough and you have your shell world. But it can only be achieved incrementally - build a bit at a time, use it and build more. It isn't realistically possible to do it any other way given the scale of investment needed.

Last edited by Antius (2016-05-05 14:05:31)

SpaceNut · 2016-05-05 20:09:08

There are only the imaginations to make use of for what will and or could be done to allow the surface to cool and to capture the gasses of the atmosphere rather than seeing them blown eventually away as the sun gets larger and hotter.
I like the idea of using the near venus asteriods and other rock bodies to help in the contruction process to shade venus coupling that material with what we can get from the atmosphere we could actually achieve creating a sheild.
I am thinking that the shield should be more like a mesh with panels that are spaced to allow the right amount of sunlight to still reach the surface. Quite possibly the sections that are not blocking could have a lense to spread the light out so as to defocus it making it less concentrated on the surface per meter.

Tom Kalbfus · 2016-05-06 00:09:43

Antius wrote:

Building a shell around a planet 8000 miles wide is a task of mythic proportions. Thousands of trillions of tonnes of material - millions of cubic miles of whatever you end up using. In comparison, a sun orbital mirror would weight a few billion tonnes. It is therefore at least a million times less massive than any realistic shell. And you build it in space and not a toxic atmosphere. It is still a massive task - orders of magnitude more massive than the most massive structure ever produced by man. But at least foreseeable at capability levels that we are likely to have in the next few centuries. I guess I am looking for ways of transforming Venus into something useful that are remotely achievable using real-tech. I dont think these discussions are worth anything unless there are real ways of achieving them.
It is hard to imagine any large scale human presence on Venus until surface conditions are more habitable. That means tolerable temperatures and pressures that allow people to breath nitrogen based air without narcosis. Not necessarily breathable air on the surface, but less than crushing pressures. Once that is achieved you can start building habitats using surface materials and incrementally extend them over the planet. Take that process far enough and you have your shell world. But it can only be achieved incrementally - build a bit at a time, use it and build more. It isn't realistically possible to do it any other way given the scale of investment needed.

I never actually envisioned humans in hard hats constructing it. By the time we are terraforming planets, we will be long past building anything, our machines will do the building, and our machines will build more of themselves, if we build them right, they will be our servants for a time, instead of competing with us or taking over. Though I think if we build something smarter and more capable than ourselves, they will cease to be our servants in short order, but I figure so long as they are servants we might as well make them do something useful, like terraform planets before they go their own way. The machines don't need terrformed planets for themselves, they could "live" in space! Building a shell world only requires several more replications of themselves that building a giant solar sail to block the Sun.

But I was thinking of some other ideas too. We could get the machines to build "white lasers". White is a mixtures of all the colors of the rainbow. What you do is take seven lasers of different colors and shine them into a prism at different angles. Now for each wavelength of light the angle of refraction is different, that is why prisms split white light into a spectrum. What I propose is the opposite, used a bunch of lasers to create a spectrum, shine it into a prism, and the prism combines it into white light. That is all the different wavelength are refracted to the same angle so they travel outwards in a single beam of white light, which could substitute for sunlight. I figure a mechanism like this could be how we would generate artificial sunlight from the underside of each sphere, because as we know, laser light can be quite bright, easily as intense as the Sun, and to a human eye, the white light can be made indistinguishable from sunlight, thought they are actually lasers shining down from the ceiling. We can project whatever we want on the underside of each sphere, make day and night whatever length we want, we could have seasons and climate zones of any climate we want, and it doesn't matter where on the planet.

Terraformer · 2016-05-06 06:16:48

I don't think producing very large numbers of (nitrogen?) filled reflective balloons is going to be anywhere near as difficult as building a shell. You wouldn't need them to completely cover the planet, either. Would they get kept out of the polar regions by upper atmospheric winds, I wonder? As they break down and fall to the surface, you can keep building more to replace them.

Tom Kalbfus · 2016-05-06 08:50:33

Terraformer wrote:

I don't think producing very large numbers of (nitrogen?) filled reflective balloons is going to be anywhere near as difficult as building a shell. You wouldn't need them to completely cover the planet, either. Would they get kept out of the polar regions by upper atmospheric winds, I wonder? As they break down and fall to the surface, you can keep building more to replace them.

Imagine a person in a balloon, wearing a gas mask and a protective suit, he is standing on a gondola in the upper atmosphere of Venus, inflating silvery balloons with a tank of compressed nitrogen and then releasing them. Do you think that's going to do anything?

Terraformer · 2016-05-06 09:42:37

Tom, you're the one suggesting that robots will be doing everything... or are you suggesting men in hardhats building your shell?

Tom Kalbfus · 2016-05-06 10:21:22

Just a little sarcasam. I was suggesting that terraforming a planet is not an act humans could do through the sweat of their brows. Basically we would need a lot of robots and/or nanotech, If humans were to do it, we would need so many humans. the resulting planet would have standing room only! We need robots to build robots to build robots and then do something, and then dispose of themselves when they are done. that way humans can inhabit the resulting terraformed planet.

SpaceNut · 2016-05-06 21:10:04

With a planet that has been there since the dawn of earth's time we can afford to go slow unless we have credible facts that we are in peril....

The initial shade just needs to stay put while the planet cools so that we can send in the first wave to teraform the planet.

The shade can be light weight probably of simular materials to that of a solar sail to create the shade if we are bring them to the planet. Other wise we just need the robotics to reproduce such an item on orbit....

Tom Kalbfus · 2016-05-07 08:47:07

The less material, the thinner it will be, but the thinner it will be the more it will be pushed toward the Venus. So it has to be located out beyond Venus L1, or else we could simply put the shade in orbit around Venus to form a cylinder that completely blocks light from the Sun.

This shade is 12,616 km wide, which at the minimum distance of Venus from the Sun, would completely block all the light from the Sun. the Outside of the shade is Solar collectors and radiators, the inside is a bank of lasers powered by the Sun. Before you object to the inefficiency of lasers, I must point out that the collecting area of this solar array/Sunshade is 12,616 by 39,500 km which is 498,332,000 square km, The solar collecting area of Venus is 115,066,184 square km, which means it has 4.33 times the solar collecting area as the Surface of Venus, since Venus gets 1.93 times as much radiance per square meter as the Earth, the collecting surface collects 8.3569 times as much solar energy as the laser energy needed to be generated, so to fully reproduce the Sun's radiance as seen from Earth, these lasers need to be 12% efficient. That is the laser array needs to generate 12% of the energy that is fully collected by the Venus shade array from the Sun, that is the photovoltaics to generate the electricity, plus the electricity to light illumination by the laser array needs in totoal be 12% of all the energy received by the Solar Array from the Sun. If that is not enough, we could always increase with width of the shade or make its radius larger for more Solar collecting area.

Last edited by Tom Kalbfus (2016-05-07 09:05:55)

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Re: Nested Sphere around Venus

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