76 Doppler Effect
In a paper he presented to the Bohemian Scientific Society in 1844, Doppler presented
his theory that the motion of objects moving toward an observer compresses sound and light
waves so that they appear to shift to a higher tone and to a higher frequency color (blue).
The reverse happened if the object was moving away (a shift toward red). He claimed that
this explained the often observed red and blue tinge of many distant stars’ light. Actually, he
was wrong. While technically correct, this shift would be too small for the instruments of
his day to detect.
Doppler was challenged to prove his theory. He couldn’t with light because telescopes
and measuring equipment were not sophisticated enough. He decided to demonstrate his
principle with sound.
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