Terra-forming Venus vs Mars

Moon: The Moon on Earth serves many purposes, it is easily seen to affect the tides, but it is almost undisputed that the biggest role the Moon has on Earth is maintaining the Earths tilt. http://yellowmagpie.com... Now what is the tilt of Venus and Mars in respect to Earth? Earth = 23.5 degrees Mars = 25 degrees Venus = 177 degrees http://en.wikipedia.org... http://www.nasa.gov... http://www.universetoday.com... Venus has a hell of a tilt, but what exactly does 177 degrees equal? If a planet has a tilt of 180 degrees, then it is upside down, so Venus actually has an axis of tilt of about 3 degrees, is UPSIDE DOWN, and spins the wrong way. Mars on the other hand is already similar to Earth tilt wise meaning that the seasons between Earth and Mars would be very similar compared to that of Venus and Earth. However the tilt tells another story, tilt of planets is vital because tilt determines the seasons of a planet, meaning that planets with no tilt or an extreme tilt (like Venus) would not have seasons, just day and night where the area around the equator would be bombarded with heat while the poles would receive much less heat. So if you take into account the tilt of Venus, along with the very close proximity of Venus to the sun, average temperatures of Venus ranges around 410 degrees Celsius, and that is not going to change. Earth's average temperature is about 14 degrees Celsius, Mars's average temperature is about -90 degrees http://quest.nasa.gov... http://imagine.gsfc.nasa.gov... http://www.universetoday.com... Now if Mars and Venus would have to be similar to Earth, than these planets would need moons proportional to themselves like that of Earth to the moon. Venus is almost the size of Earth, meaning that if a massive moon would have to be found and brought very close to Venus for such a thing to work. Mercury is the only thing close by for Venus, but Mars on the other hand is about half the size of the Earth, meaning that a moon for Mars would be much smaller than Mercury, and with an asteroid belt nearby it could be feasible that overtime asteroids could be moved towards Mars, caught, then clustered to form a moon. Something that would be much easier overtime then nuking Mercury towards Venus and hoping that Mercury isnt destroyed in the process. http://sciencenetlinks.com... So to summarize my arguments up to this point, Mars is much similar to Earth temperature wise, seasonal wise, tilt wise, and could be altered moon wise much easier than Venus. Carbon argument Mars has more than enough CO2 to support plant life similar to Earth, and the amount of CO2 in Mars's atmosphere is similar to that of Earths Mars = 25% Earth = .039% Venus = 96.5% http://en.wikipedia.org... http://en.wikipedia.org... http://en.wikipedia.org... So if we are to terraform both planets to have similar atmospheres to Earth, Mars is a much easier task than Venus is percentage wise. What about Nitrogen? Same links as above Venus = 3.5% Mars = 2.7% Earth = 78% So both Venus and Mars are very different from Earth Nitrogen wise, BUT consider this.... Mars is a lot smaller than Venus, so boosting the Nitrogen levels on Mars would be much quicker than boosting it on Venus because Mars's atmosphere is smaller but already more stable than that of Venus's SO2 aka Sulfer dioxide Venus = 150 ppm (parts per million) Earth = <.01 ppm Mars = unknown There arent many sources showing what % of Mars's atmosphere is S02, but since its not listed it is very very small. Basically, the amount of SO2 in Earth's atmosphere is similar to that of Mars's, and the atmosphere of Venus is saturated with SO2 in comparison to Earth and Mars. ============================================================================ ============================================================================ There are several other factors needed to be considered when wondering what must be done and what is needed to support human life on other planets similar to that of Earths. So far we have focused on changing the atmosphere fo the planets, examining temperature likeness to that of Earth, and examining seasonal changes, and a moon. Mars triumphs Venus in all of these categories since Mars is much smaller and can be manipulated more easily then Venus and is already similar to Earth already. Now for the other factors that must be considered, Water Exploitable resources Habitable at all? Water Mars has been found to at one point have had running water on its surface, and the planet right now has a large amount of water locked within the polar ice cap of the planet located at the North Pole. http://en.wikipedia.org... Venus on the other hand at 400 degrees Celsius has absolutely NO water either frozen on land or anywhere in its atmosphere, meaning that Early colonization of the planets by a population of humans could be supported water wise on Mars today, whereas such a colonization of Venus water wise is impossible and will remain so for a very long time. Exploitable Resources Resources on Venus are almost entirely focused on the chemicals of the atmosphere of Venus, Carbon, Oxygen, Lead, that kind of stuff, nothing of very high value though. Mars on the other hand actually has a handful of metallic ores that could be used for trade or building civilization, such as Tin, Iron, Copper, Silver, and a few others. This means that when looking to colonizing Mars or Venus, Mars offers resources that can both be used to fund such transformations or carry out the transformations themselves.... Ill end here for now :)