Well, it's like this. Mars is too small to hold a decent atmospher, but it's got a whole lot more rock than our Moon does, and we can rip that bitch to pieces and make comfy rotating space stations out of it and make it disappear, while we don't want to have our Moon disappear, because a lot of natural things are tied to it, like tides, or women pmsing go based on lunar cycles, and it's got to be controlled by whatever minor gravitational or light effect the moon has, at least in its origin, even if there might be a biological clock inside that does the actual counting. So you can take some material from the Moon - such as dig to the cold lava free nonmolten core and hope to find some gold, nickel and platinum you could dump to earth, or just use rocks from the surface to build a megagiga flippable solar panel shade system against global warming near the Earth-Sun Lagrange point, controllable via a remote down here, so that we can dump all the carbon back into the atmosphere from underground where it went during the carboniferous, jurassic and palezoic and the like, and give it back to lifeforms to use, via an increase of CO2 from 0.03% to say 0.1% in the air, which is like a limiting nutrient to all green plants growing, that filter their own carbon content - carbohydrate, fat and protein - directly from the 0.03% in the atmosphere and it takes a long time to filter huge volumes of air for a little bit of carbon, so global warming this global warming that we should dump all fossil fuels into the atmosphere as long as we can guarantee a shading over say the sahara or diffuse over some less reflective than sahara Ocean regions - and this means they'd have to flip open and close on the clock - so if we can drop temperatures back, you might even get things like the Levant becoming fertile grounds like it was 2000 years ago and it's pretty much desert these days, but of course the climate behavior of the Earth is complicated and all that, so it would be nice to have shades up there, as solar panels, as long as you can guarantee that if things go haywire and it naturally falls away from lack of yearly fuel delivery that keeps it up there, because some apocalypse took over down here, or the retards took over and they can't make a delivery, so you have to consider the ramifications of putting the carbon back into the atmosphere, so even before then the prime concern is self sufficient sustainable rotating cylinder space stations via full recycling from Moon materials, and a whole lot of people living in space sustainably, such as China is running out of room, but there is a lot of room in space, and they make great astronauts because of smaller body size and they are not heavy to lift up, so you can put a lot of people up there first, before you install shades, and you can do it from lunar materials - but you should keep most of the Moon intact and instead go for Mars (which is faaaaaaaaaar, but not too far), and you are welcome to rip Mars to pieces to make homes and space stations out of it and almost everyone could live down here on Earth if they get to keep the Moon intact, yet have not 7 billion, but 100 trillion humans living happily in outer space on space stations made from Mars, and 5 billion kept down here as a museum and natural reservation, while Venus is getting terraformed by a shade system, or by banging comets into it on their trip back from the Sun, over millions of years, to lift Venus higher into orbit away from the Sun, to make it naturally colder in case the shade system fails, but hopefully not interfering much gravitationally with the orbit of Earth by coming too close. If anything the shade system, which is required to be superhuge for Venus compared to modifying merely 1% or so of Earth's total solar dose, with Venus you're probably talking covering 30-50% or even more of the total surface area with shades before the sulfuric falls onto the ground as a big ocean, and Venus starts filtering and gabbing oxygen at 32, and oxygen reacted hydrogen as water at 18 on its surface, ultimately the sulfates ending up in rock as drywall, and water oceans covering Venus surface. It would take tiiiiime. But you'd get a 2nd livable planet as Venus with oceans on the surface that can house whales, something that may not be worthwhile on space stations, lest they be huge to give enough roaming room for whales to long distance communicate across half an ocean via low frequency sounds. Venus has good potential, moreover a thick atmosphere too that makes it uneconomical to lift objects from it into orbit compared to Mars with an atmosphere at a 0.6 to 1.1% of Earth's pressure, where wind resistance might be so little that you could shoot a fast enough cannon ball towards outer space, and it would actually go all the way into outer space orbit, because the atmosphere does not burn it up at its fairly low escape velocity, because Mars is so small. If you could hoard a lot of mini-debris and make it bigger, then it could be terraformed and contain an iceage planet, and hold water, but Earth's average temperature is already close to water's freezing point, so to both hold water gravitaionally and have it liquid too at the same time it would have to be close to Earth in both size and temperature, which means a huge Fresnel lens capturing and focusing extra sunlight unto its surface, and if you can come up with all that debris - such as stealing Jupiter's moons from its orbit, and stealing Saturn's ring (which has a lot of easy to get to debris) if you add all that up, go fish for Pluto and send that down plummeting into Mars too, combine a lot of rocks from the asteroid belt, then you could terraform Mars possibly easier than waiting for Venus to capture water and make the sulfuric disappear. Btw Venus sulfuric might disappear into rocks instantly, within a year or two if covered with a huge shade, and the planet have a rocky surface like Mars with good gravity, and a very low pressure of say 0.5 atmosphere of pure oxygen from on the ground electrolyzers in no time, or pure oxygen/CO2 mix, which is not breathable, but its better than nothing while you wait for the nitrogen and water to gather, so Venus might be easier to terraform than Mars, if all you want is a barren rocky planet to walk on, and even if you built up Mars to proper size that Venus already has, Mars would have to wait longer to gather all the nitrogen from the solar wind, because it's less dense that far away (any kind of flux from a sphere drops as 1/r-squared, magnetic, electric, gravitational, energy, or mass flow, because of conservation laws). But even on Mars you could have a temporary O2/CO2 atmosphere while people on it carry helium packs made from nuclear physics reaction helium, and recycled. You cannot have an O2/He atmosphere, it can only be O2/N2 to be breathable, because if helium is held by gravity/low temperature, at 4, that's too close to H2 hydrogen at 2, and you can only end up with an ever increasing in size gas giant like Jupiter, Uranus, Saturn and Neptune, and unlivable, even if you start with a seed the size of Earth or a bit bigger at a distance of Mars' orbit. So you will always have to provide a gravity/temperature that holds H2O at 18, N2 at 28 and O2 at 32 while at the same time boiling off H2 at 2 and He at 4, to keep it livable. Presently Mars' atmosphere is almost all CO2 at 44, with a bit of N2 at 28, meaning it's reducing, just like Earth was at the beginning before the appearance of photosynthetic lifeforms, and it probably has a lot of carbon and sulfur and metals like meteoritic iron (or even nickel) unoxidized that hog any oxygen that appears in its atmosphere. Conversely Venus is mostly H2SO4 at 96, with some CO2, but it's really really hot, boiling off even O2 and N2, even if its surface clouds have a lot of solar reflectivity. Venus needs a humongous shade system, probably put up by robots and very thin black shades, or silicon solar panel shades, and it's better to fuck with it first before you fuck with Earth, because even if you fuck up the shading of Venus, the planet itself is presently fucked and it cannot be fucked up any worse, so it's like you're not fucking up anything. But as I said, Venus would need a huuuuge area covered, counting that it's almost the same size as Earth at a much shorter distance, and say, it's half the distance to the Sun as Earth then it receives 2 squared equals 4 times the amount of solar energy per area, and to make it 1 again, 3 out of the 4 would have to be covered up, or 75% of total area shaded, or more like 75% of the solar input would have to be diffusely reflected or filtered away by silicon panels at red in orbit at its Lagrange point. Maybe heat engines that work between say 2000C focused solar concentrators in orbit and 600C red heat heat emitters (emitting away from Venus via a mirror block) into outer space cooling would be better than silicon solar panels as shade, that close to the Sun. Aluminum mirrors, aluminum being abundant, might work, except that aluminum melts at 660C or so, and even then it's not a good heat radiator because it's not black, and if molten it would want to coalesce into spherical droplets of molten aluminum floating at Venus' Lagrange point, so silicon with a much higher melting point and a darker color and high abundance in the Universe may be after all the best shade material, even if not very useful to make electric at that high temperature over there, while still being a shade. Near Earth the solar dose per surface are is much smaller, and the top temperature attained by solar panels must not be too hot else they would not be used on satellites. I should look up how much closer to the Sun Venus is than Earth and revise this post, but ehh, it's going under -1 karma so I'll be lazy won't bother. Yeah. Stuff like that. And while we're at it, fuck Obamacare (not Obama, just Obamacare, or more like just the penalty part of that whole bullshit, the rest, like helping people pay if they apply is fine), fuck Monsanto, etc, which will guarantee it stays at -1. :)