Olive said:
Can someone give me aquick run down on how terraformign would work, how long it would take etc.
Depending greatly on the planet being terraformed, and the method of terraforming, it realistically could take anywhere from thousands of years to hundreds of thousands of years. Science fictional technology, of course, can decrease the time frame greatly.
The methods very widely, but essentially, you are tring to turn another planet into a place that's earth-like... that is, a place where humans, and other earth creatures could live without the necessity for artificial life support.
That means you first have to find an appropriate planet... Mars is the best choice in our solar system, with Venus a distant second. Mainly, you are looking for a planet in approximately the right orbit (since that's the toughest thing to change) from its sun, with enough gravity to keep you and an atmoshpere sticking to the ground, and an existing environment that isn't too hostile (a cold, low pressure world is easier to deal with than a hot, high pressure world).
Next, you have to make the changes. Add water, oxygen, and nitrogen. Maybe a little carbon dioxide for the green house effect. Lay down some top soil. There are many ways to do it... You build terraforming factories that mechanically or chemically produce the right elements. Or you could bio-engineer plants (beginning with bacteria, algae, lichens and moss) that survive in the planet's current environment and excrete the components of the evironment you want. In a sci-fi setting, you can simply use advanced tech to take the molecules and atoms apart and rebuild them into what you want.
Olive said:
Is a situation like that in the show Firefly fiesable (ie. all the planets/moons look like borderline desert)?
Probably not all of them. Mars could certainly be turned into a 'cold' desert, and Venus has potential as a 'hot' desert, though it would much more difficult to terraform. As for the others... Mercury is far too hot and small to mess with. Jupiter, Saturn, Uranus and Nepture are all gas giants too large to mess with*. Pluto and all the moons are too small and too cold to mess with**. Asteroids aren't even worth mentioning.
*Although, it is entirely feasible that a layer that has earth-equivalent gravity, temperature and pressure could exist within a gas giant's atmosphere. The down side is that there is no ground... You have to find a way to suspend all your habitats in mid-air (think Cloud City from The Empire Strikes Back). A failure of your suspension system would be catastrophic.
**Europa, however, has a surface crust of ice... It is theorized that a liquid layer of water may exist deep beneath this ice layer, and if is does, it could support organisms similar to those that live in our deepest oceans.
