Svartkroppar

Svartkroppar, also known as black bodies, are theoretical objects in physics that absorb all incident electromagnetic radiation, regardless of frequency or angle of incidence. They are idealized entities used as a benchmark for understanding thermal radiation. A perfect black body, when in thermal equilibrium, emits thermal radiation that is dependent only on its temperature. This emitted radiation, known as blackbody radiation, spans a spectrum of wavelengths.

The spectral distribution of blackbody radiation was a significant puzzle in late 19th and early 20th-century physics. Classical physics, particularly the Rayleigh-Jeans law, failed to accurately describe the observed spectrum, leading to the "ultraviolet catastrophe," where the predicted intensity of radiation at short wavelengths diverged to infinity. Max Planck's groundbreaking work in 1900 resolved this issue by proposing that energy is not emitted or absorbed continuously but in discrete packets called quanta. This concept of energy quantization was fundamental to the development of quantum mechanics.

The energy of a quantum is proportional to the frequency of the radiation, a relationship expressed by Planck's law: E = hf, where E is the energy, h is Planck's constant, and f is the frequency. The intensity and spectral distribution of blackbody radiation are described by Planck's law of blackbody radiation, which accurately matches experimental observations across all wavelengths. While perfect black bodies do not exist in nature, many objects, like stars, exhibit very close approximations. The concept of blackbody radiation is crucial in astrophysics for determining the temperature of celestial bodies and in various engineering applications involving heat transfer and optical properties.