AST 104 Lecture Notes - Lecture 4: Black-Body Radiation, Emission Spectrum, Chemical Element
Document Summary
We can use electromagnetic radiation to measure properties of incredibly distant objects, even though we"ll never visit them! They"re all made up of the same stuff. The same elements are found throughout the universe. They"re all subject to the same rules. We"ll focus on a few specific types of spectra: Blackbody radiation: the continuous thermal spectrum emitted by a theoretically perfect absorber/emitter of all light (no reflection at any wavelength). Two laws of thermal radiation to describe the phenomenon. Wien"s law : hotter objects emit light with shorter peak wavelengths. The peak emission wavelength (or the wavelength where the emission is most intense) shortens as its temperature increases. Stefan- boltzmann law: each square meter of a hotter object"s surface emits more light across all wavelengths. The total amount of energy emitted per square meter of an object"s surface (or the total area under the curve) increases as its temperature increases.
