2,273 research outputs found
Deduction of Lorentz Transformation from the existence of absolute rest. Deduction of the speed of light in any frame of reference
We begin by admitting the following: (i) there is a frame of reference where
the speed of light is the same in any direction (that speed is c) (ii) the
average speed of light on a two-way journey is c in every frame of reference.
From this two premises we obtain an expression for the speed of light which
implies the speed of light depends on the motion of the frame of reference.
Also from this two premises solely we deduct Lorentz Transformation.Comment: 6 pages, 0 figure
The Energy-Entropy Principle
In this paper, through a criticism of what we call the paradigmatic view of
thermodynamics, we aim at showing a new perspective attained in this matter.
The generalization of heat as internal energy (generalization of the kinetic
energy concept of heat) permits the generalization of the Kelvin postulate: "It
is impossible, without another effect, to convert internal energy into work"
(no reference to heat or to heat reservoir).Comment: 18 pages, 1 figur
The physical meaning of synchronization and simultaneity in Special Relativity
Based on two previous papers, the physical meaning of synchronization and
simultaneity as is presented in Einstein's Special Relativity paper of 1905 is
reconsidered. We follow Einstein's argumentation to introduce a criterium of
synchronization and for the same arguments we arrive at a different criterium
for synchronization. From that we conclude that simultaneity is absolute.Comment: 11 pages, 0 figure
Is the assumption of a special system of reference consistent with Special Relativity?
In a previous work we have shown that the null result of the Michelson-Morley
experiment in vacuum is deeply connected with the notion of time. The same is
true for the the postulate of constancy of the two-way speed of light in vacuum
in all frames independently of the state of motion of the emitting body. The
argumentation formerly given is very general and has to be true not only within
Special Relativity and its `equivalence' of all inertial frames, but as well as
in Lorentz-Poincar\'e scenario of a preferred reference frame. This paper is
the second of a trilogy intending to revisit the foundations of Special
Relativity, and addresses the question of the constancy of the one-way speed of
light and of the differences and similarities between both scenarios. Although
they manifestly differ in philosophy, it is debated why and how the assumption
of a "special system of reference experimentally inaccessible" is indeed
compatible with Einstein's Special Relativity, as beautifully outlined and
discussed by John Bell [1]. This rather trivial statement is still astonishing
nowadays to a big majority of scientists. The purpose of this work is to bring
such assertion into perspective, widening the somewhat narrow view of Special
Relativity often presented in textbooks.Comment: 16 pages, 6 figure
Comment on 'A one-way speed of light experiment'
A recent paper published in Am. J. Phys. describes an experiment designed to
measure the one-way speed of light. Although the experiment is very
interesting, in particular to be used in student laboratories, it is in fact
determining the two-way speed of light.Comment: 1 page, submitted to the American Journal of Physic
The conceptualization of time and the constancy of the speed of light
In this work we show that the null result of the Michelson-Morley experiment
in vacuum is deeply connected with the notion of time. It can be deduced
without any mathematics only from the assumption that all good clocks can be
used to measure time with the same results, independently of the machinery
involved in their manufacturing.
A second important assumption, intrinsic to the very notion of time, is that
clocks measure time in the same way in different frames, i.e., the notion of
time is the same in all inertial frames. Under this assumption, we point out
that the "postulate" of constancy of the "two-way" speed of light in vacuum in
all frames independently of the state of motion of the emitting body is also
strongly related to the concept of time, together with the existence of a limit
speed in the "rest frame". This postulate simply results from the construction
of clocks where tic-tacs are made by objects traveling with the limit speed.Comment: 5 pages, 4 figure
The concepts of work and heat and the first and second laws of thermodynamics
A simple and effective approach to thermodynamics is suggested, which solves
the major difficulties in the traditional presentation of the subject. The
internal energy is introduced from the behavior of deformable bodies, whereas
the importance of keeping in mind the microscopic picture is emphasized. A
straightforward model is used to show that the internal energy depends on the
volume and entropy, from where the relationship between mechanics and
thermodynamics is immediate, mechanics corresponding to isentropic
thermodynamics. The questions of evolution to equilibrium and irreversibility
are studied under the light of the action of the "dynamic force", which has a
dissipative character. The present formulation leads to a discussion and
clarification of the physical meaning of various thermodynamic quantities, such
as pressure, temperature, work and heat. The adiabatic piston problem is
analyzed, as a paradigmatic case where the notions of "adiabatic" and "heat
transfer" are often ill-defined
Special Relativity in Absolute Space: from a contradiction in terms to an obviousness
This work deals with the questions of absolute space and relativity. In
particular, an alternative derivation of the effects described by special
relativity is provided, which is based on a description that assumes a
privileged reference frame. The present theory follows the ideas of Lorentz and
Poincare, abandoning a strict view of Einstein's "equivalence" of all inertial
frames. The meaning of the Principle of Relativity is discussed and elucidated,
and it is shown that it is not incompatible with the existence of a preferred,
absolute, frame. Most scientists nowadays still consider the basic assumptions
of the theory proposed here to be plain wrong. Moreover, they tend to see an
irreconcilable conflict between the Lorentz-Poincare and the Einstein-Minkowski
formulations. However, as stated by John Bell [Bell1988], although there is a
stringent "difference in philosophy" between both views, "the facts of physics
do not oblige us to accept one philosophy rather than the other". The validity
of Bell's assertion is unambiguously demonstrated, and it is shown how and why
both approaches do indeed agree in the description of (most of?) the physical
phenomena. Evidently, the physical meaning of the different physical quantities
- such as "time", "speed", "simultaneity" and "synchronization" - is quite
different in both programmes. And yet, for perplexing it may look at first
sight, the present theory, developed under the Lorentz-Poincare assumption of a
preferred reference frame, somehow encompasses Einstein's theory. There is no
conflict, as there is one theory. It is stressed that reality is not changed by
the choices one makes to describe it, so it is not changed by the particular
way in which the clocks have been set.Comment: 36 pages, 7 figures. Submitted to the PIRT publication projec
A relativistic time variation of matter/space fits both local and cosmic data
Cosmic observations strongly support a time varying scenario for
matter/space. On the other hand, so far, observations at solar system scale
failed to identify any time variation on matter/space characteristics. To
explain both results it is enough to consider a time variation of physical
parameters liable to account for cosmic observations but satisfying Relativity
Principle at least at local scale (we called it Local Relativity Property).
Here, for the first time, a relativistic time varying scenario is defined from
redshift and Cosmic Microwave Background characteristics. It is showed that it
can match both cosmic and local data. Although undetectable in each local
measure, such relativistic scenario has detectable time dependent consequences
at Solar System scale, namely a receding component in the motion of the Moon, a
past warmer climate and, this being new, an accelerating component in Earth
rotation. A new class of cosmological models can now be explored, without
concepts like dark matter, valid at both local and cosmic scale, and such that
fundamental physical laws and Relativity Principle hold in any point of time
and space.Comment: 14 pages, 4 figures, EPS-12, Budapest (2002
Cosmological Principle and Relativity - Part I
The absence of an identified consequence at solar system scale of the
cosmological space expansion is usually explained considering that space
expansion does not affect local anysotropies in matter distribution. This can
also be explained considering a time dependent scenario compatible with
Relativity Principle, therefore supporting physical laws independent of the
time position of the observer. A theory considering such relativist scenario,
i.e., generalizing Relativity Principle to position, embodies Cosmological
Principle and can be intrinsically able to fit directly both local and cosmic
data. In part I it is presented the general framework of such a theory, called
Local Relativity (LR), and analysed the space-time structure. Special
Relativity space-time is obtained, with no formal conflict with Einstein
analysis, but fully solving apparent paradoxes and conceptual difficulties,
including the simultaneity concept and the long discussed Sagnac effect. In
part II, LR is applied to positional analysis. It is verified the accordance
with solar system measurements and with classic cosmic tests, without dark
matter or dark energy. Two of the new features obtained in part II are the
possibility of a planetary orbital evolution compatible with a null
determination for G variation, supporting a warmer scenario for earth (and
Mars) past climate, and the possibility of an accelerating component in earth
rotation, compatible with the most recent measurements.Comment: 29 pages and 6 figure
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