Säteilytasapaino

Säteilytasapaino refers to the balance of incoming and outgoing radiation for an object or a system, particularly relevant in fields like atmospheric physics, climate science, and astrophysics. It describes a state where the rate at which an object absorbs energy from its surroundings, primarily through radiation, is equal to the rate at which it emits energy. This equilibrium ensures that the object's temperature remains relatively stable over time.

In the context of Earth's climate, the planet is in a state of approximate radiative balance. The Earth receives solar radiation, which is absorbed by the surface and atmosphere. Simultaneously, it emits thermal infrared radiation back into space. When these incoming and outgoing energy fluxes are equal, the planet's average temperature is maintained. If there is an imbalance, such as an increase in greenhouse gases trapping outgoing radiation, the planet warms until a new balance is achieved.

The concept is also applied to stars and other celestial bodies. A star like the Sun is in hydrostatic and radiative equilibrium. The outward pressure from nuclear fusion in its core balances the inward pull of gravity, while the energy produced by fusion is transported outward by radiation. Deviations from radiative balance can indicate changes in stellar activity or evolution. Understanding radiative balance is crucial for modeling climate change, predicting stellar evolution, and comprehending the energy budgets of various planetary systems.