The physicist's conception of space-time underwent two major upheavals thanks to the general theory of relativity and quantum mechanics. Both theories play a fundamental role in describing the same natural world, although at different scales. However, the inconsistency between them emerged clearly as the limitation of twentieth-century physics, so a more complete description of nature must encompass general relativity and quantum mechanics as well. The problem is a theorists' problem par excellence. Experiment provide little guide, and the inconsistency mentioned above (...) is an important problem which clearly illustrates the intermingling of philosophical, mathematical, and physical thought. In fact, in order to unify general relativity with quantum field theory, it seems necessary to invent a new mathematical framework which will generalise Riemannian geometry and therefore our present conception of space and space-time. Contemporary developments in theoretical physics suggest that another revolution may be in progress, through which a new kind of geometry may enter physics, and space-time itself can be reinterpreted as an approximate, derived concept. The main purpose of this article is to show the great significance of space-time geometry in predetermining the laws which are supposed to govern the behaviour of matter, and further to support the thesis that matter itself can be built from geometry, in the sense that particles of matter as well as the other forces of nature emerges in the same way that gravity emerges from geometry. Scientific research is not a process of steady accumulation of absolute truths, which has culminated in present theories, but rather a much more dynamic kind of process in which there are no final theoretical concepts valid in unlimited domains. (David Bohm). (shrink)

We analyze the situation of an observer coaccelerated relative to a linearly accelerated charge, in order to find whether he can observe the radiation emitted from the accelerated charge. It is found that the seemingly special situation of the coaccelerated observer relative to any other observer, is deduced from a wrong use of the retarded coordinate system, when such a system is inadmissible. It is also found that the coaccelerated observer has no special position other than any other observer, and (...) hence, he can observe any physical events as any other observer. (shrink)

In the framework of classical electromagnetism, a charge however accelerated with respect to an inertial frame radiates energy, in any circumstance. Regarding the energy as made of photons, the hypothesis is here introduced that the emission of a photon is only possible as a result of a change of the energy of the charge, which requires an energy-work exchange with the accelerating field. On such an hypothesis an elementary impulsive-dissipative model for the photon emission is constructed, in the framework of (...) special relativity, in which no energy radiation is emitted from a charge in a central Coulomb field uniformly describing a circular orbit. (shrink)

A new non-traditional quasi-classical description of the particle dynamics (QCDPD) is outlined. The “quasi-classical” attribute is suggested by the closeness—although not identity—to the description of a classical system, in the framework of classical dynamics. Founded on a suitable one-to-one mapping of the timelike 4-vectors of Minkowski's spacetime onto the real 4-dimension vector space, QCDPD is mathematically equivalent to the traditional description of special relativity. However, in QCDPD a new frequency fulfilling the same transformation law as the frequency of an oscillator (...) is employed. It turns out that the special-relativity particle is, in fact, modeled as an oscillator which is essentially classical. The associated wave is a natural consequence of such a model. (shrink)

We present a derivation of the homogeneous Lorentz transformations that arrives immediately at the general form without the usual specialization in thex direction.