lecture four. attempts to save ether hypothesis status michelson-morley experiment shows null result
Post on 22-Dec-2015
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Attempts to Save Etherbefore
Special Relativity
1. Contraction Hypothesis
2. Ether-Drag Hypothesis
3. Modify Electrodynamics
Ether-Drag Hypothesiscontradicted with
• Stellar aberration(Bradley 1727)
• Fizeau convection coefficient(Fresnel 1817, Fizeau 1857)
Modify Electrodynamics
Emission Theories The velocity of a light wave is
connected with the motion of the source rather than with an ether.
Modify ElectrodynamicsEmission Theories
• The velocity of light is c relative to the original source.
• This velocity is independent of the state of the medium transmitting the light.
Emission Theoriesare contradicted with
• de Sitter observations on binary stars
• Michelson-Morley experiment using extraterrestrial light source
Conclusions• The speed of light is the same in
all inertial systems, independent of the relative motion of source and observer.
• A relativity principle applicable both to mechanics and to electrodynamics.
Conclusions• Galilean transformations must be
replaced.
• The laws of mechanics which were consistent with Galilean transformations needs to be modified.
Principle of Relativity
• include all laws of physics•no measurements to designate an inertial system as intrinsically stationary or moving
Principle of Relativity
•no experiment entirely within an inertial system can tell the motion with respect to any other.
Program of the Theory
•nature of time
•transformation keeping velocity of light constant
•Lorentz transformation
Einstein• In his early life none of his
“elders” recognized his genius.• Until almost thirty he had
never seen a real theoretical physicists, “except in the mirror!”
Einstein• statistical mechanics• atomic nature of matter• special relativity• principle of equivalence• light quanta hypothesis• specific heat of solids