ON THE ELECTRODYNAMICS OF MOVING BODIES
https://www.fourmilab.ch/etexts/einstein/specrel/specrel.pdf
ON THE ELECTRODYNAMICS OF MOVING BODIES
By A. Einstein
June 30, 1905
It is known that Maxwell's electrodynamics--as usually
understood at the present time--when applied to moving
bodies, leads to asymmetries which do not appear to be
inherent in the phenomena.
Take, for example, the reciprocal electrodynamic action
of a magnet and a conductor. The observable phenomenon
here depends only on the relative motion of the conductor
and the magnet, whereas the customary view draws a sharp
distinction between the two cases in which either the one
or the other of these bodies is in motion. For if the
magnet is in motion and the conductor at rest, there
arises in the neighbourhood of the magnet an electric
field with a certain definite energy, producing a current
at the places where parts of the conductor are situated.
But if the magnet is stationary and the conductor in
motion, no electric field arises in the neighbourhood of
the magnet. In the conductor, however, we find an
electromotive force, to which in itself there is no
corresponding energy, but which gives rise--assuming
equality of relative motion in the two cases
discussed--to electric currents of the same path and
intensity as those produced by the electric forces in the
former case.
Examples of this sort, together with the unsuccessful
attempts to discover any motion of the earth relatively
to the "light medium," suggest that the phenomena of
electrodynamics as well as of mechanics possess no
properties corresponding to the idea of absolute rest.
They suggest rather that, as has already been shown to (1)
the first order of small quantities, the same laws of
electrodynamics and optics will be valid for all frames
of reference for which the equations of mechanics hold
good. We will raise this conjecture (the purport of which
will hereafter be called the ``Principle of Relativity'')
to the status of a postulate,
and also introduce another postulate, which is only (2)
apparently irreconcilable with the former, namely, that
light is always propagated in empty space with a definite
velocity c which is independent of the state of motion of
the emitting body.
These two postulates suffice for the attainment of a
simple and consistent theory of the electrodynamics of
moving bodies based on Maxwell's theory for stationary
bodies.
The introduction of a "luminiferous ether" will prove
to be superfluous inasmuch as the view here to be
developed will not require an "absolutely stationary
space" provided with special properties, nor assign a
velocity-vector to a point of the empty space in which
electromagnetic processes take place.
And, of course the paper goes on to develop the ideas
and make his case...
Special relativity
https://en.wikipedia.org/wiki/Special_relativity
In physics, special relativity (SR, also known as the
special theory of relativity or STR) is the generally
accepted and experimentally well-confirmed physical theory
regarding the relationship between space and time. In Albert
Einstein's original pedagogical treatment, it is based on
two postulates:
The laws of physics are invariant (i.e. identical) in all
inertial systems (non-accelerating frames of reference).
The speed of light in a vacuum is the same for all
observers, regardless of the motion of the light source.
It was originally proposed in 1905 by Albert Einstein in the
paper "On the Electrodynamics of Moving Bodies". The
inconsistency of Newtonian mechanics with Maxwell's
equations of electromagnetism and the lack of experimental
confirmation for a hypothesized luminiferous aether led to
the development of special relativity, which corrects
mechanics to handle situations involving motions at a
significant fraction of the speed of light (known as
relativistic velocities). As of today, special relativity is
the most accurate model of motion at any speed when
gravitational effects are negligible. Even so, the Newtonian
mechanics model is still useful (due to its simplicity and
high accuracy) as an approximation at small velocities
relative to the speed of light.
Not until Einstein developed general relativity, to
incorporate general (or accelerated) frames of reference and
gravity, was the phrase "special relativity" employed. A
translation that has often been used is "restricted
relativity"; "special" really means "special case".
4 Consequences derived from the Lorentz transformation
4.1 Relativity of simultaneity
4.2 Time dilation Muon Example
4.3 Length contraction Muon Example
4.4 Composition of Velocities
5 Other consequences
5.1 Thomas rotation
5.2 Equivalence of mass and energy
5.3 How far can one travel from the Earth?
6 Causality and prohibition of motion faster than light
Mass-energy equivalence
https://en.wikipedia.org/wiki/Mass-energy_equivalence#The_first_derivation_by_Einstein_(1905)
The correctness of Einstein's 1905 derivation of E = mc2 was
criticized by Max Planck (1907), who argued that it is only
valid to first approximation. Another criticism was
formulated by Herbert Ives (1952) and Max Jammer (1961),
asserting that Einstein's derivation is based on begging the
question. On the other hand, John Stachel and Roberto
Torretti (1982) argued that Ives' criticism was wrong, and
that Einstein's derivation was correct. Hans Ohanian (2008)
agreed with Stachel/Torretti's criticism of Ives, though he
argued that Einstein's derivation was wrong for other
reasons. For a recent review, see Hecht (2011).
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