In Search of the Aether Lecture 1

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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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## In Search of the Aether Lecture 1

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### In Search of the AetherLecture 1

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