06:38 Nov 14, 2009 

Thank you ILAINE.

21:02 Nov 13, 2009 

To round up the observations here, it must be noted that, while lots of sun energy arrive in parts of the electromagnetic spectrum that are not blocked by the greenhouse gases, and thus reach and heat the Earth, energy radiated by the Earth is in the infrared, and that part of the spectrum is blocked by greenhouse gases, creating the effect. This in analogy with a real greenhouse, where energy trying to radiate out of the greenhouse, all in the infrared, is blocked by glass, or other "transparent" materials, and stays inside the greenhouse.