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Nice description ofthe DOPPLEE SHIFT
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----- Forwarded message from chaiselongue@earthlink.net -----
Date: Fri, 12 Nov 2004 10:12:14 -0800
From: Carolyn <chaiselongue@earthlink.net>
R
The short version:
Born: November 29, 1803 in Salzburg, Austria
Died: March 17, 1853 in Venice, Italy
Christian Doppler was educated in Vienna and taught in Prague, Schemnitz and
at the Polytechnic Institute in Vienna (precursor to today's Vienna
University of Technology), where he became Professor of Practical Geometry
in 1850. His main fields of research were mathematics and electricity.
In greater detail:
Christian Doppler
(1803-1853)
Christian Johann Doppler was a nineteenth century physicist and
mathematician who is most often remembered for his discovery of the Doppler
effect, which is central to modern conceptions of sound and light. He was
born on November 29, 1803 in Salzburg, Austria, the son of a stonemason.
Though it was planned for him to enter the family trade, his chronically
poor health prevented him from doing so. Instead, he studied mathematics at
the Vienna Polytechnic Institute, graduating in 1825. Afterwards, he briefly
returned to Salzburg before enrolling at the University of Vienna, where he
remained until 1829.
Doppler acted as a mathematical assistant and tutor after completing his
studies, but had extreme difficulty in receiving a professorship. At one
point he almost emigrated to America in hopes of better prospects, but
finally received an offer from the State Secondary School in Prague. A few
years later, in 1837, Doppler began teaching at the Polytechnic School
located in the same city and was formally appointed to a professorship there
in 1841. Then, in the final years of his career, Doppler became Director of
the Institute of Physics at the University of Vienna.
Although often occupied with his teaching duties, Doppler managed to find
time for independent research. His earliest work concerned mathematics, but
in 1842 Doppler completed and published the paper On the Colored Light of
Double Stars and Certain Other Stars of the Heavens. Within the work, he
proposed that observed frequency of light and sound waves is dependent upon
how fast the source and observer are moving relative to each other, a
phenomenon commonly referred to as the Doppler effect. He also correctly
predicted that his theory would some day be utilized by astronomers to more
accurately measure the movements and distances of stars.
Doppler's ideas were initially received with a certain amount of skepticism
so, in order to support his claims, he devised an extremely unusual
experiment. In 1845, with the help of a colleague, Doppler arranged for a
train to carry an open car full of trumpeters back and forth along a section
of track. Alongside, another group of musicians stood by and recorded their
perceptions of the pitch of the instruments. The innovative test proved
successful, confirming Doppler's prediction that as the trumpets approached
the musicians heard a higher pitch, which became noticeably lower as the
train passed by.
Demonstrating that the Doppler effect also held true for the frequency of
light proved more difficult and was never successfully achieved before
Doppler's death in 1853. The first experiment that revealed a Doppler shift
in starlight was carried out at the beginning of the twentieth century.
Since that time, however, the Doppler effect has proven invaluable for
astronomical observations, paving the way for a host of new scientific
discoveries and concepts. Most notably, the motions of stars detected
through this manner led to the development of the big bang theory of the
universe.
© 1995-2004 by Michael W. Davidson and The Florida State University. All
Rights Reserved.
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