AST101H1 Lecture Notes - Lecture 8: Oort Cloud, Kuiper Belt, Interstellar Cloud

• School: UTSG
• Department: Astronomy & Astrophysics
• Course: AST101H1
• Professor: Michael Reid

Document Summary

Opaque object emits light via thermal radiation. Graph-wise: for hotter objects, whole spectrum moves up. Graph-wise: for hotter objects, peak of the spectrum moves to the left (shorter wavelength, higher energy) Graph: spectrum has same shape; temperature decides everything. Sound is a wave in air whose pitch is determined by frequency. Sound/light coming towards you, frequency/pitch is higher [shorter wavelengths aka blueshift] Sound/light moving away from you, frequency/pitch is lower [longer wavelengths aka redshift] Effect depends on how close the source speed is to the speed of the wave (but speed of light wave moves very fast -> almost no effect) Doppler shift tells us only the portion of an object"s speed that is directed toward or away from us (radial component); not about how fast it is moving across our line of sight (tangential component) The faster the object is rotating, the broader in wavelength the spectral lines become.