AS101 Lecture Notes - Lecture 13: Photon, 30 Foot Fall, Cosmic Microwave Background
Document Summary
Different types of sources emit different ranges of wavelengths. Cosmic microwave background: shows us the last remaining heat from the big bang and gives us clues to the early history of the universe. Since radio waves have larger wavelengths, we need large mirrors to get good angular resolution. Another way to improve angular resolution: combine signals from several telescopes. In most ways, infrared optics are not that different from visible light. The problem is that earth"s atmosphere blocks a lot of ir. Ir telescopes also need to be insulated from heat. We can learn more from light if we understand more about how light interacts with matter: how it is emitted and absorbed. Spectroscopy: breaking light from an object into its different wavelengths, and comparing the amounts of light emitted at different wavelengths. Hotter objects emit more radiation than cooler ones: wien"s law: Continuous spectra are produced by dense objects with many atoms packed together.
