Suppose that the Earth acts as a blackbody of radius 6.4 × 106 m and effective temperature 240 K. (This is not the same as our surface temperature, due to our atmosphere's intervention. Most outgoing infrared ultimately leaves from the upper atmosphere.)
(a) What is the flux of energy leaving the Earth's surface for outer space?
(b) What is the total rate of emission of energy by the entire Earth?
(c) The flux of sunlight sweeping through space at our position is 1.4 kW/m2. Earth's temperature remains constant on the average. What fraction of the incident solar radiation is absorbed by the Earth? (Caution: The area intercepting the sunlight is not the same as the total area of the Earth that emits.)