i'm in the 12th grade and the question is to research the environmental conditions on each of the planets in the solar system other than earth. and to evaluate each planet as a potential place for human colonization and to identify what challenges would be faced, and how they could be met?
You've asked for much more information than I could type in a reasonable amount of time, so I hope you don't mind if I point you toward a good resource and give you some ideas to think about. The web site I am thinking of is a guide to the solar system by Students for the Exploration and Development of Space. Their web site is: http://www.seds.org/nineplanets/nineplanets/nineplanets.html This page has links to most objects in the solar system, and contains a lot of information about each one.
Here are some ideas to think about when reading each page and considering how humans could live there:
1) Air and Water - people need oxygen to breathe and water to drink and grow food. Taking water and oxygen from the Earth is very expensive and very difficult, so it would be easiest to colonize places where sources of water and /or oxygen are easy to find. (Note that if there is lots of water, oxygen can be made from the water. Also, if there is carbon dioxide, oxygen can be made.)
2) Food - people will need to grow their own food on another planet - transportation to and from Earth is, again, too expensive. Plants need carbon dioxide and sunlight (real sunlight is best; artificial lighting will work, too.)
3) Energy - human settlements will need to create their own energy. Close to the sun (say, within the asteroid belt), solar power is useable. Outside of the asteroid belt, nuclear power would most likely have to be used. There are advantages and disadvantages to each type of power.
4) Radiation - radiation is harmful for people, plants and animals. On Earth, we are protected by a magnetic field and an atmosphere. Some planets and moons have neither; some have only one or the other. Very few have both. Some planets have very strong magnetic fields that create even more radiation. Settlements will have to be protected to some degree.
5) Gravity - planets or moons with a lesser gravitational pull than the Earth will result in astronauts having smaller bone and muscle mass, a serious problem if they are to come back to Earth. The closer a planet's gravity is to Earth, the less of a problem this is.
6) Atmosphere - Some planets have no atmosphere. Some have atmospheres that will crush people. Generally, it's easier to deal with low-pressure rather than high-pressure, but both are dangerous if there is an air leak.
7) Distance - the further a planet is from Earth, the harder it is to get to and to talk to!
8) Temperature - Is the planet/moon too hot, too cold, or just right? The hotter or colder a planet is, the more energy it will take to change the temperature.
9) Miscellaneous - Some moons have active volcanoes that cover the entire moon with boiling lava regularly. Some planets have no ground. And there is psychology - how will people deal with living isolated on an alien rock for long periods of time? Etc.
There is a lot to think about, so you may want to focus in on certain of the above topics. All in all, Mars is probably the best choice for long-term human settlement. It may even be possible to change Mars' atmosphere to resemble the Earth! The moon is the most logical first step, because it is very close. Venus might seem like a good choice, but it is really a very bad choice. It is very hot, has a crushing atmosphere, and may be covered with molton lead.
There is another web site you might find useful: http://spaceflight.nasa.gov/mars/index.html This is a NASA web page that talks about exploring Mars and other planets.
Good luck, and thanks for writing!
Sincerely, Kurtis Williams