What will the first galaxies that formed after the Big Bang look like?
Current theories of galaxy formation suggest that the birth process for these vast systems of stars may be very violent events, and will be billions of times brighter than our Sun. Such events may remain visible at highly redshifted wavelengths. That is, although much of the energy produced is emitted in the ultraviolet, it will be redshifted into the infrared by the time it gets to us because of the extreme distance (in space and time) from the present. • What is redshift and how do you measure it? Redshift is a special astronomical case of a physical phenomenon called the Doppler effect (after Johann Doppler [1803-1853]). The Doppler effect occurs when a source sending out waves (either sound or light) is moving with respect to an observer. When the source is moving toward the observer, waves arrive earlier than they would in the stationary case and the wave peaks arrive closer together (the sound is higher pitch or the light is bluer). If the source is moving away from the observer,
