Solar energy strikes the top of the Earth’s atmosphere at a rate of 343 W m⁻². About 30 per cent of this energy is reflected directly back into space by the Earth or the atmosphere. The Earth–atmosphere system absorbs the remaining energy and re-radiates it into space as black-body radiation. What is the average black-body temperature of the Earth? What is the wavelength of the most plentiful of the Earth’s black-body radiation?