Astronomy 162 - Stars, Galaxies, & The Universe

The "fixed stars" are really in constant motion, but these motions are too small to see with the human eye in a human lifetime. This lecture introduces proper motions (apparent angular motion of the stars in the sky), radial velocities (motion towards or away from us measured using the Doppler Shift of the star's spectral lines), and true space velocities, measured by combining three key observables: the proper motion, radial velocity, and distance to the star. Recorded 2006 January 10 in 1008 Evans Laboratory on the Columbus campus of The Ohio State University.