NATS 1745 Lecture Notes - Lecture 12: Annie Jump Cannon, Stellar Classification, Black Body
15 Feb 2016
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Microscopic level: how the atoms move, how dense, the temperature and how old it is. Note: astronomers use the kelvin temperature scale, similar scale to celsius. 0 kelvin (aka absolute zero) = -273 degree celsius. Doesn"t matter what is heated, after the element reach a certain temperature they generate the same spectra. Objects are fainter even though very high temperature because compared to other object, the higher temperature"s wavelength is less visible in the visible part. Key property of blackbody graph: it doesn"t matter what the black body is made from: iron. Nickel, glass, etc: graphs will all be the same and only depend on temperature. Bohr"s model: electrons orbit the nucleus, the electrons can only be in specific orbits with specific energy, atoms emits light (pieces of light are photon ) as an electron drops from high energy orbit to low energy orbit. Energy difference is used to create a photon.
