The Dawn of Modern Physics

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The Dawn of Modern Physics
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Topics

• Newtonian Physics
• In Search of the Aether

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Newtonian Physics

• Newtons Laws
• Law of inertia
• Law of motion
• Law of action and reaction
• Law of gravity
• Maxwells Equations
• Thermodynamics

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Newtonian Physics
We can scarcely avoid the conclusion that light
consists in the transverse undulations of the
same medium which is the cause of electric and
magnetic phenomena. James Maxwell, 1866
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Newtonian Physics
Moreover, light travels in this medium at the
speed of 300,000,000 m / s
A major goal of physicists of the late 19th
century was to detect Earths motion through
this medium the aether
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In Search of the Aether
It was argued (in the late 1870s), that the
aether should be flowing past the Earth at a
speed close to 30 km/s, assuming the aether to
be at rest relative to the Sun and the other
stars.
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In Search of the Aether
Michelsons 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
Swimmer 1
Swimmer 2
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In Search of the Aether
Michelson Experiment (1881)
Michelson-Morley Experiment (1887)
http//erwin.phys.virginia.edu/classes/109/lecture
s/michelson.html
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In Search of the Aether
The result of the hypothesis of a stationary
aether is thus shown to be incorrect. A. A.
Michelson Am. J. Sci., 122, 120 (1881)
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There is nothing new to be discovered in physics
now. All that remains is more and more precise
measurement. Lord Kelvin, 1900