Shifts in the lines of absorption in the spectrum of visible light
When astronomers view distant objects through the telescope, they find that the more distant objects have a larger red shift. This means that their light is shifted towards the red end of the spectrum; in other words, the wavelengths have become longer than for similar objects seen close to us. They interpret this as meaning that these distant objects are receding from us and that objects farther away are receding from us faster. It’s a little like the Doppler effect that makes sound have a lower pitch when the source is traveling away from us. The faster an object travels, the larger the change in pitch. However, some properties of the red shift call this interpretation into question; these are the subject of the article that follows. One such property is the quantization of red shifts. They seem to occur in abrupt steps rather than continuously, which has interesting implications for the study of the universe. This suggests that the red shift may be caused by something other than the expansion of the universe, at least in part.