ASTRON C10 Study Guide - Quiz Guide: Orbital Period, Geocentric Model, Lunar Phase
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ASTRON C10 Full Course Notes
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Stars : huge, opaque, luminous balls of gas held together by gravity. Have no actual rest mass but has an energy given by planck"s constant x frequency. Can act as both particles and light waves. Photons of higher energy have higher frequency and shorter wavelength. Discrete energy levels : exists in certain well-defined energy levels. Cooler outer layers absorb certain wavelengths derive chemical composition. Hot, thin body (for ex, gas) emits discrete, bright lines called . When radiation from opaque body goes through thin body, gas removes radiation and. Doppler effect happens when a source of waves is moving from your perspective (ex. ambulance) Useful in astronomy: electromagnetic radiation from faraway stars seems to be shifting downward in frequency, towards the red end of the spectrum, signalling that they are getting further away and that the universe is expanding. Objects of different temperatures emit spectra that peak at different wavelengths. Hotter objects emit most radiation at shorter wavelengths (around blue)
