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Tidally Lock Venus To Partially Terraform?

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he box to come up with this as it's a whacky option that's so crazy it just might work. I wouldn't have thought of it in a million years.


  • Throw tens of thousands of large asteroids or Kuiper belt objects at Venus to speed up its rotation till its day equals its sun, locking one side permanently towards the sun.
  • The sunny side would be perfect for solar energy
  • the CO2 would drop and fall on the dark side
  • We would colonise the middle twilight ground
  • Creates amazing energy potential on the sunny side
  • Deals with CO2 once and for all
  • Tens of thousands of asteroid impacts might dig up metals from under Venus, and the material from the asteroids would be mined by the future Venus colony

As Jon says:

“Once one half of the planet is in perpetual darkness, the equatorial winds will die, the night side will cool and within decades carbon dioxide will rain down in the dark to form a hemisphere of dry ice with an eventual average depth of some two kilometres. That is nothing excessive, we have mountain ranges on Earth about four times as high. Sulphur compounds and water would have settled out earlier, ready for mining at need, a repository of concentrated chemical feedstocks for industrial purposes.

As a generalisation, industrial chemists love concentrated chemical feedstocks; high concentrations tend to increase yields and reduce costs.”

One thing that confuses me (as a humanities geek not a technical geek) is Jon’s claim about the weather. Why is only the CO2 freezing on the night side, and not all the nitrogen and oxygen? I’m wondering if anyone can calculate the coldest the cold side gets? Nitrogen freezes a below -195.79 °C and oxygen is -218.8 °C This PDF suggests that if Earth were tidally locked, it would be under -100 °C on the dark side, but is that an average or is there somewhere even colder where all the atmosphere would eventually freeze? I guess if Earth is "only" - 100, then Venus, with twice the sunlight on the hot side, would have a lot more energy to spread to the dark side. There's a big difference between CO2's -78.5 °C and nitrogen and oxygen's freezing points. I just hope there's no margin of error on the cold side that would see the vital life supporting gases freezing?

Jon continues:-

“Between night side and day side there would be a twilight belt, the zone where the sun approaches the horizon. It would be girdled by an enormous stationary smoke ring, a steady and permanent wind of more than hurricane force blowing towards the warm side, balanced by high altitude winds blowing towards the cold. Like the climatic belts on Earth, but much more stably, there would be weaker convection cells on either side of the twilight zone, combining into a planetary conveyer belt bearing harmful gases to the night side where they would freeze out. This convection would also warm the night side, preventing part of the rest of the atmosphere from freezing out once the carbon dioxide had settled. No runaway greenhouse concerns on Venus, either hot or cold!”

That's an amazing picture. If the good gases like nitrogen and oxygen are not freezing, then this idea permanently and naturally deals with the CO2 once for all. No need for all the giant tractors of Kim Stanley Robinson's proposal. (See below).

The tidal PDF discusses water cycles.

“Perhaps some of the water could be found in a liquid state near the boundary between the hot and cold regions and one could expect some kind of water cycle, with something like glaciers being continually melted by the warm air blowing in from the hot side, with the melted water flowing in gigantic rivers to the hot side, where it evaporates and cycles back around to fall as snow on the cold side.”

TIDALLY LOCKED VERSUS MORE TRADITIONAL SOLAR SHIELD APPROACH? So what do you make of it all? What merits do you see to this plan over the more traditional solar shield plans or floating colony plans? What about other schemes with giant airships colonies slowly converting the atmosphere into carbon nanotubes for more colonies? What about the Kim Stanley Robinson proposal of a giant solar shield blotting out the sun so the whole planet freezes at once, and then giant robotic tractors spray rock foam over the CO2 to lock it down? This was in the Nebula award winning 2312. Then instead of moving tens of thousands of large asteroids into Venus, we'd 'only' have to move a few and then 'only' spin them out into solar shields? (Sure, this probably relies on 3d printing and space manufacture schemes we haven't invented yet!) Then we'd have access to a frozen surface. Make the solar shields Solar PV, and we could microwave energy down to the surface to power the colony and run the automated tractors covering the CO2. Who knows, by then we might have uses for that CO2. Carbon nanotube factories might scoop it up and build space elevators and Orbital Rings around Venus with it, ready to launch thousands of carbon-nanotube space habitats out from the Orbital Ring! That way, the CO2 is not a problem to get rid of, but an incredible resource creating worlds for billions and billions to live in. Would we stop with the CO2, or would we disassemble the planet to build Rung-Worlds and the start of a Dyson Swarm?

COLONIES OR PLANETS OR BOTH? Or, are we not ready for O'Neil colonies and the much larger McKendree cylinders yet? Do you think we're too addicted to Earth, and just want to use 10,000 asteroids to speed up Venus to 24 hours instead, and try and terraform it into a more traditional Earth 2.0? Is that even possible on a planet that receives twice the sunlight? What are your thoughts?

MARS FIRST? Lastly, and I guess this is how this whole conversation started: where would you put your space dollars first? Colonising Venus or Mars or somewhere else? I'd personally pick Mars because it "only" needs Elon Musk to land a million people on Mars and then they can start terraforming it on their own. Once they've got it up to "Green Mars" status (basically Earth like but with a CO2 atmosphere), then they could start moving on to the asteroid belt to hurl things back in at Venus. Seen as a stepping stone to those 10,000 asteroids, Mars is 'on the way' to Venus.

The goal for Mars is a city of a million people in 100 years. https://www.youtube.com/watch?v=0qo78R_yYFA

Then they can cook the planet over the next 100 years by emitting super-greenhouse gases 17,000 times as powerful as CO2. I love the big benefits we get from cooking Mars (once we've established there's no life there). A city of a million people has the economic base to start mass producing super-greenhouse gases. The Martian CO2 poles warm and melt. Mars would then have a CO2 atmosphere about a third the pressure of sea-level air here on Earth. That gives us radiation protection from the sun and cosmic rays. It lets us walk on Mars in plain clothes (with an oxygen breather mask of course). It melts water ice, creating oceans and a rain cycle, which in turn allows plants and trees and farming on the surface and plankton in the oceans. All that about 100 years after the million-strong colony starts releasing super-greenhouse gases. Amazing!https://www.universetoday.com/9730/zubrin-on-terraforming-mars/

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  • 2 months later...

Here is one way to terraform Venus


The shade is in a 24-hour orbit around Venus completely blocking all the sunlight that would otherwise fall on the planet, one can do other useful things with the energy obtained, such as produce antimatter for instance for starships. the orbit doesn't have to be a 24-hour orbit, that is just the orbit I used in this diagram. If you block out all the sunlight, you can add back the amount of sunlight you need to produce Earthlike conditions on its surface. I also would suggest we mine the atmosphere of Uranus for the hydrogen we need to make oceans out of Venus' carbon-dioxide atmosphere. There is a chemical reaction where we combine hydrogen with carbon-dioxide to produce water vapor and graphite. the water vapor will rain out and produce oceans for Venus, and if we converted most of the carbon-dioxide, it will produce oceans that cover about 80% of the planet's surface. on the inside of this shade we reproduce the sunlight that the Earth receives using the power the solar collectors receive from the Sun on the outside. Since Venus receives more sunlight than it needs, this process does not have to be 100% efficient. With this arrangement we can produce a 24-hour day-night cycle for Venus, by altering the intensity of the Sunlight produced on the inside, we can create an Earthlike seasonal cycle as well. Venus has very little axial tilt with two major continents, Aphrodite and Ishtar. Ishtar has a high latitude, but by varying the light it does not have to have a polar climate, and neither does the continent of Aphrodite need to be tropical just because it is on the equator. This light show comes a lot cheaper than altering the rotation of a planet the size of Venus. reflecting or blocking sunlight is after all easier than moving a planet.

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