Light Spectrum
        Absorption / Emission Lines
 
            Absorption Lines
                If there is an absorbing material (such as a cooler gas cloud) between you and the blackbody, then you will not see a complete continuous spectrum

                Emission Lines
                If we look at the cool gas without the blackbody in the line of sight, we will see an emission line spectrum
                colors of the lines we see are exactly the same colors that were missing from the absportion line spectrum
              

 
    Telescopes
        Optics
            Reflecting
                
 
            Refracting
        

            Radio
                long wavelength
                low frequency
                low energy
                able to have radio telescope on the surface of the earth
                            http://science.nasa.gov/headlines/images/arietids/etaaquaridecho.wav

            Infrared
                can be detected on earth
                better detection out in space
                Spitzer
                    http://www.spitzer.caltech.edu/spitzer/