ASTR 3 Chapter 2-2: Astronomy 3 Textbook 2.2 Notes
Document Summary
White light can be separated into red, orange, yellow, green, blue, and violet hues. Can separate beam of white light into rainbow called spectrum by passing through prism. We see different colors becuse eyes react differently to waves of different frequencies. Visible light spectrum covers wavelength range from 400 to 700 nm. Entire range of electromagnetic radiation: long wavelength has radio and infrared radiation. They all make up the electromagnetic spectrum, all are basically the same, move at same speed ( c ). Electromagnetic spectrum often expressed in logarithmic scale, with frequency and wavelength increasing/decreasing by factors of 10. Only small fraction of radiation arriving at earth from space reaches. Earth"s surface because of opacity of earth"s atmosphere. Opacity: extent to which radiation is blocked by material through which it"s passing. More opaque object is, less radiation gets through. In much of radio and all visible portion of the spectrum, opacity is low.
