2:30: Okay, so why hasn't the sun warmed Mercury, Venus, and Uranus?
The warming of these planets is due to the Milankovich cycle. Pluto is warming because it's closer than usual to the sun. Let's think about this: Pluto has warmed a tenth of a degree. At its closest, it's 30AUs from the sun (i.e., 30 times Earth's average orbit). Solar energy reduces by an inverse square with distance, so if the sun's warming Pluto by a certain amount, then the sun will be warming Earth by 30^2, or 900, times that amount. That should correspond to a 90-degree warming of our planet--which would boil away the oceans!
