Blackbody radiation refers to the electromagnetic radiation emitted by an idealized object (a blackbody) that perfectly absorbs all incident radiation and re-emits energy solely based on its temperature.
Key characteristics:
- A blackbody does not reflect or transmit any radiation—only emits.
- Its emission spectrum depends only on temperature, not on material or surface properties.
- At higher temperatures, it emits more radiation and shifts toward shorter wavelengths (e.g., from infrared to visible light).
Why it matters:
Blackbody radiation is foundational in quantum physics and thermodynamics. It led to the development of Planck’s radiation law, resolving the “ultraviolet catastrophe” predicted by classical physics. Real-world examples include the cosmic microwave background radiation and the approximation of stars, like the Sun, as blackbodies.