Terraforming, in it's most basic definition, is to change any large celestial object (planet, moon, mini planet, etc.) into a naturally inhabitable planet.

There have been so many theories on how it could be done, and some REALLY good one's too. In fact, many people know of the Mars mission, which has been pursued for years. One of the possible goals on that mission is to do further research on how transforming the planet into an Earth esque world could be accomplished.

Here's an artists rendition of what that world might look like. And another. (I linked, because they're big.)

Quoting Wikipedia:

Quote Originally Posted by Wikipedia
Terraforming Mars would entail two major interlaced changes: building up the atmosphere and keeping it warm.The atmosphere of Mars is relatively thin and thus has a very low surface pressure of 0.6 kPa, compared to Earth's 101.3 kPa. The atmosphere on Mars consists of 95% carbon dioxide (CO2), 3% nitrogen, 1.6% argon, and contains only traces of oxygen, water, and methane. Since its atmosphere consists mainly of CO2, a known greenhouse gas, once the planet begins to heat, more CO2 enters the atmosphere from the frozen reserves on the poles, adding to the greenhouse effect. This means that the two processes of building the atmosphere and heating it would augment one another, favoring terraforming. However, on a large scale, controlled application of certain techniques (explained below) over enough time to achieve sustainable changes would be required to make this theory a reality.
Do you think it's a good idea, or a bad one? Discuss.