A relatively simple question: Suppose we have a dark non-reflective body at rest in space and hit it with fair amounts of radiation. This would cause the body to heat up because it absorbs most of the radiation. After some time would the body cool down? The first guess is that it would, but why would it cool down, where does the energy from the radiation go? If we start with a body at rest, put energy into it and end up with the initial scenario then this goes against conservation of energy, right?