[Shiraz (Ray)]

Hi Trent.
As I understand it, every planet reaches an equilibrium temperature and stays there unless something changes. Equilibrium occurs when the total energy coming in from the sun, combined with any internal energy percolating up from the core, is exactly balanced by the thermal IR energy being radiated back out into space. If the planet does not have an atmosphere, all of the IR energy is radiated by the surface and the temperature is a pretty straightforward function of the distance from the sun. If there is an atmosphere with greenhouse gases, then some of the energy heading outwards from the surface is absorbed by the atmosphere and re-radiated into space by it's upper layers. But the atmosphere also radiates energy back downwards as well, so the temperature at the surface ends up being higher than it would otherwise be. On Venus the temperature is MUCH higher because the atmosphere is very greenhouse active, but it is still in equilibrium and it will stay essentially constant unless something changes - as far as I know, the only planet currently undergoing a change that could affect it's equilibrium temperature is the earth.