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In Search of the Aether Lecture 1 Topics In Search of the Aether Lorentz and Fitzgerald Summary In Search of the Aether Michelson’s clever idea: Speed of water relative to bank V m/s Speed of swimmers relative to water C m/s One swimmer is bound to win b l a c l
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Topics • In Search of the Aether • Lorentz and Fitzgerald • Summary
In Search of the Aether Michelson’s clever idea: Speed of water relativeto bank V m/s Speed of swimmers relativeto water C m/s One swimmer is bound to win b l a c l
Motion Relative to Water Swimmer 1 Swimmer 2
Motion Relative to Water Swimmer 1 l Swimmer 2 l l
Motion Relative to Water Swimmer 1 total time Swimmer 2 total time
Motion Relative to Water Swimmer 1 total time Swimmer 2 total time where
In Search of the Aether Michelson Experiment (1881) Michelson-Morley Experiment (1887) http://erwin.phys.virginia.edu/classes/109/lectures/michelson.html
In Search of the Aether “The interpretation of these results is that there is no displacement of the interference bands. … The result of the hypothesis of a stationary aether is thus shown to be incorrect.” A. A. Michelson, Am. J. Sci., 122, 120 (1881)
“There is nothing new to be discovered in physics now. All that remains is more and more precise measurement.” Lord Kelvin, 1900
Lorentz and Fitzgerald Fitzgerald (1851-1901) Lorentz (1853-1928) http://www-history.mcs.st-and.ac.uk/~history/Mathematicians
Their Solution The time for light path 1 can be made equal to that for path 2 if the length of path 2, somehow, shrinks by a factor of γ
Summary • Michelson and Morley failed to detect the motion of the Earth through the aether • Their conclusion: the aether could not be stationary. This implied that the aether moves along with the Earth • Lorentz and later Fitzgerald suggested that objects contract along the direction of motion in such a way as to make the light travel times the same