12 research outputs found
On a modified-Lorentz-transformation based gravity model confirming basic GRT experiments
Implementing Poincar\'e's `geometric conventionalism' a scalar
Lorentz-covariant gravity model is obtained based on gravitationally modified
Lorentz transformations (or GMLT). The modification essentially consists of an
appropriate space-time and momentum-energy scaling ("normalization") relative
to a nondynamical flat background geometry according to an isotropic,
nonsingular gravitational `affecting' function Phi(r). Elimination of the
gravitationally `unaffected' S_0 perspective by local composition of space-time
GMLT recovers the local Minkowskian metric and thus preserves the invariance of
the locally observed velocity of light. The associated energy-momentum GMLT
provides a covariant Hamiltonian description for test particles and photons
which, in a static gravitational field configuration, endorses the four `basic'
experiments for testing General Relativity Theory: gravitational i) deflection
of light, ii) precession of perihelia, iii) delay of radar echo, iv) shift of
spectral lines. The model recovers the Lagrangian of the Lorentz-Poincar\'e
gravity model by Torgny Sj\"odin and integrates elements of the precursor
gravitational theories, with spatially Variable Speed of Light (VSL) by
Einstein and Abraham, and gravitationally variable mass by Nordstr\"om.Comment: v1: 14 pages, extended version of conf. paper PIRT VIII, London,
2002. v2: section added on effective tensorial rank, references added,
appendix added, WEP issue deleted, abstract and other parts rewritten, same
results (to appear in Found. Phys.
Towards a quantum universe
In this short review we study the state of the art of the great problems in
cosmology and their interrelationships. The reconciliation of these problems
passes undoubtedly through the idea of a quantum universe.Comment: 7 pages, Accepted for publication in Astrophysics & Space Scienc
Atoms and the universe: an account of modern view on the structure of matter and the universe
+254hlm.;22c
Times, theories and practices in social psychology.
This paper begins by problematizing the `taken for granted' status of Newtonian linear time at the heart of (social) psychology. Borrowing from Adam, the paper makes a distinction between an `events in time' and `time in events' approach to social psychology. It argues that a `time in events' approach helps to reveal the importance of multiple times for social psychological theories and practices. To demonstrate this approach, it considers some of the multiple times that are relevant for analysing the concept of `identity'. It also explores the multiple times of the research encounter. In doing so, it suggests that traditional dichotomies in social psychology between synchronic and diachronic methods, and between experimental and qualitative methods, can be dissolved by this focus on the temporal. The paper concludes with some observations about the importance of time for thinking about social psychology as a knowledge-producing practice