Astronomy 1021 Lecture Notes - Lecture 8: Circumpolar Constellation, Electromagnetic Radiation, Photon

• School: Western University
• Department: Astronomy
• Course: Astronomy 1021
• Professor: Robert Cockcroft

Document Summary

All matter emits and absorbs light, but at different wavelengths depending on composition and temperature. Smooth surface: mirror like reflection in particular direction. Rough surface: scattering; reflection in variety of directions. Most objects we see in everyday life reflect scatter light transmission. The light often (cid:498)bent(cid:499) - this is called refraction e. g. sun appears distorted at sunset because of refraction in earth"s atmosphere. Also the reason why the skies are blue. Blue light is more easily scattered than red. Light takes a longer path through the atmosphere at sunset. More blue light gets scattered out at sunset. An object that absorbs all light is opaque. An object that only partially absorbs is translucent. Light can act either like a wave or like a particle (light particles are called photons) Frequency: number of times per second that wave vibrates up and down. A wave is a pattern of motions that can carry energy without carrying matter along with it.