ASTRON C10 Lecture Notes - Lecture 5: Thermal Radiation

• School: Berkeley
• Department: Astronomy
• Course: ASTRON C10
• Professor: Filippenko Alex

Document Summary

Thermal radiation: radiation emitted by an object that"s emitting on it"s own as a result of atoms and charged particles accelerating and moving all around and emitting radiation in the process a. If you"re a perfect object of this type (no such thing except black hole and universe) then you absorb incident radiation, it heats you up, and you re- emit it at shorter wavelengths i. The higher the temperature, the shorter the wavelength of light is that is emitted at its peak a. b. This is because the electrons and charged particles are moving around more quickly. The frequency of oscillations are bigger so the frequency of the light emitted are bigger (bluer light) Wien"s law is only true for black bodies but the phenomenon still applies for all objects. Per unit surface are, hot opaque thermal emitters give off much more energy than cold ones i. ii.