I posed this question in the Earth section of the forums, but I think I wasn't clear enough in how I posed my question, plus I think the question is more physics than earth science. I have decided to try posing my question as a series of questions building to the main point. This is because I think I must have some basic misunderstanding and perhaps we can identify that early on. I loosely follow several blogs that are sceptical of 'global warming'. However, there is a fundamental point that I keep running into that I just don't 'get'. It is the matter of the greenhouse effect causing the earth to be warmer than it might otherwise be without an atmosphere. Please note I understand that climate change is not a topic for discussion here. I am not trying to question the greenhouse effect or suggest anything at all about climate change, the science, or societal views about the question. I am simply concerned with the mechanics of the greenhouse effect in terms of measured temperatures. My understanding is that the theoretical temperature for a body with the same albedo as earth located in an orbit at the same distance from the sun as earth and in thermal equilibrium with the incoming radiation can be calculated to be about 255K. The actual measured temperature of earth is some 287K. That warmer temperature is caused by the 'greenhouse effect' of the atmosphere. I think this means that an earth like body without an atmosphere would radiate at a temperature of 255K. I think it follows that the measured 'surface' temperature of that body must therefore be 255K. Am I correct so far?