Final answer:
The Earth does not receive the same amount of solar radiation at all locations due to its spherical shape and the angle of incoming sunlight. The Earth's energy balance is maintained through the absorption and re-radiation of solar energy, primarily infrared radiation affected by greenhouse gases. 340 W/m².
Step-by-step explanation:
Not all areas on Earth's surface receive the same amount of radiation due to the curvature of the earth and the varying angle at which the sun's rays hit different parts of the planet. The sun's energy is generated through nuclear fusion and emitted as electromagnetic radiation, which includes ultraviolet rays, visible light, and infrared rays. This radiation is crucial for maintaining the Earth's temperature.
Earth's energy balance is achieved because the energy it receives from the sun in the form of radiation is mostly re-radiated back into space. The constant temperature of the Earth is the result of this energy exchange, with infrared radiation playing a key role by being absorbed by greenhouse gases like CO2 and H2O in the atmosphere.
Furthermore, when you model the Earth as a sphere with radius R, it has a surface area of 4πR², but the Sun doesn't see the whole surface at once. Instead, it sees an effective area that is the projection of Earth—a disk of area πR². To get an average solar input across the entire planet, we divide the solar constant (the average amount of solar radiation received on a surface perpendicular to the sun's rays at Earth's orbit) by 4, thus reducing it to 340 W/m2.