AST 2003 Lecture Notes - Lecture 7: Gamma Ray, Roygbiv, Radiography
Document Summary
Light: duality: sometimes it behaves like a wave or a particle. Also comes from the earth: speed of light is a constant=c=300000 km/s or 186000 miles/s or 3 x 10^8 m/s, symphony of electromagnetic wave. Currently the sun that we see is 8 minutes old because of the time that it travelled. Every time that you look up at the sun you are looking at the past because light travels through time from when it was first given off. The farther that you go into the universe, the more into the past that you see because we never really see light in current time. When the velocity is bigger than light the universe will go dark. That is what is seen at the edge of the universe: electro-magnetic spectrum. Long wavelength to be able to listen in the mountains and other areas without interruption. Eye is able to see these waves.
