116,250 research outputs found
An Analysis of the Concept of Inertial Frame
The concept of inertial frame of reference is analysed. It has been shown
that this fundamental concept of physics is not clear enough. A definition of
inertial frame of reference is proposed which expresses its key inherent
property. The definition is operational and powerful. Many other properties of
inertial frames follow from the definition or it makes them plausible. In
particular, the definition shows why physical laws obey space and time
symmetries and the principle of relativity, it resolves the problem of clock
synchronization and the role of light in it, as well as the problem of the
geometry of inertial frames
An analysis of the concept of inertial frame in classical physics and special theory of relativity
The concept of inertial frame of reference in classical physics and special theory of relativity is analyzed. It has been shown that this fundamental concept of physics is not clear enough. A definition of inertial frame of reference is proposed which expresses its key inherent property. The definition is operational and powerful. Many other properties of inertial frames follow from the definition, or it makes them plausible. In particular, the definition shows why physical laws obey space and time symmetries and the principle of relativity, it resolves the problem of clock synchronization and the role of light in it, as well as the problem of the geometry of inertial frames
An Analysis of the Concept of Inertial Frame
The concept of inertial frame of reference is analysed. It has been shown that this fundamental concept of physics is not clear enough. A definition of inertial frame of reference is proposed which expresses its key inherent property. The definition is operational and powerful. Many other properties of inertial frames follow from the definition or it makes them plausible. In particular, the definition shows why physical laws obey space and time symmetries and the principle of relativity, it resolves the problem of clock synchronization and the role of light in it, as well as the problem of the geometry of inertial frames
Cosmological gravitomagnetism and Mach's principle
The spin axes of gyroscopes experimentally define local non-rotating frames.
But what physical cause governs the time-evolution of gyroscope axes? We
consider linear perturbations of Friedmann-Robertson-Walker cosmologies with
k=0. We ask: Will cosmological vorticity perturbations exactly drag the spin
axes of gyroscopes relative to the directions of geodesics to quasars in the
asymptotic unperturbed FRW space? Using Cartan's formalism with local
orthonormal bases we cast the laws of linear cosmological gravitomagnetism into
a form showing the close correspondence with the laws of ordinary magnetism.
Our results, valid for any equation of state for cosmological matter, are: 1)
The dragging of a gyroscope axis by rotational perturbations of matter beyond
the Hubble-dot radius from the gyroscope is exponentially suppressed, where dot
is the derivative with respect to cosmic time. 2) If the perturbation of matter
is a homogeneous rotation inside some radius around a gyroscope, then exact
dragging of the gyroscope axis by the rotational perturbation is reached
exponentially fast as the rotation radius grows beyond the H-dot radius. 3) For
the most general linear cosmological perturbations the time-evolution of all
gyroscope spin axes exactly follow a weighted average of the energy currents of
cosmological matter. The weight function is the same as in Ampere's law except
that the inverse square law is replaced by the Yukawa force with the Hubble-dot
cutoff. Our results demonstrate (in first order perturbation theory for FRW
cosmologies with k = 0) the validity of Mach's hypothesis that axes of local
non-rotating frames precisely follow an average of the motion of cosmic matter.Comment: 18 pages, 1 figure. Comments and references adde
Mach's Principle and Higher-Dimensional Dynamics
We briefly discuss the current status of Mach's principle in general
relativity and point out that its last vestige, namely, the gravitomagnetic
field associated with rotation, has recently been measured for the earth in the
GP-B experiment. Furthermore, in his analysis of the foundations of Newtonian
mechanics, Mach provided an operational definition for inertial mass and
pointed out that time and space are conceptually distinct from their
operational definitions by means of masses. Mach recognized that this
circumstance is due to the lack of any a priori connection between the inertial
mass of a body and its Newtonian state in space and time. One possible way to
improve upon this situation in classical physics is to associate mass with an
extra dimension. Indeed, Einstein's theory of gravitation can be locally
embedded in a Ricci-flat 5D manifold such that the 4D energy-momentum tensor
appears to originate from the existence of the extra dimension. An outline of
such a 5D Machian extension of Einstein's general relativity is presented.Comment: 16 pages, accepted for publication in Annalen der Physik; Revised
Version: minor improvement
On the formal statement of the special principle of relativity
The aim of the paper is to develop a proper mathematical formalism which can help to clarify the necessary conceptual plugins to the special principle of relativity and leads to a deeper understanding of the principle in its widest generality
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