Common misconception: It is in fact, not possible. For those of you that knew this already, congratulations, this world still has hope. For those of you that think it is possible: you are - sadly - not alone. Edit-1: Just looked at these responses. It seems that the most common explanation as to why you could terraform Jupiter happens to be: "[i]space magic[/i]" Touché Guardians, touché. Edit-2: For those of you that are wise enough to know that the Gas Giants are not gaseous all the way through, that is awesome for you! There is no need to repeatedly tell me that, because I'm well aware of that. Still doesn't change my feelings on terraforming Jupiter or the like. Edit-3: Wow, just checked the trending page of the forums and found this on there with 1.2K comments. Didn't realize that many people responded to this. That being said, I would like to thank the academy for this honor as well as all the internet trolls, wanna-be Neil deGrasse Tysons, and idiots. I couldn't have done it without you. Edit-4: For those of you claiming that we could just solidify the gas, here's my explanation as to why you should all go think of better things to do than argue with my pretentious ass: Take Jupiter for example: it is made of primarily molecular hydrogen and helium. If you used temperature to "un-sublime" or solidify the gas into a solid surface of sorts, you have to incorporate the melting temperature of the mostly hydrogen and helium atmosphere. For starters, the temperature to solidly molecular hydrogen is around 14K. [spoiler]If you didn't know, that's like negative 259 Celsius and is almost at absolute zero.[/spoiler] Helium is even lower at a whopping 1K Account in melting point depression phenomenon of non-pure substances and we have a real issue… lol