Foundations of Physics

, Volume 10, Issue 1–2, pp 57–76 | Cite as

Common time in a four-dimensional symmetry framework

  • J. P. Hsu
  • T. N. Sherry
This Issue Is Dedicated To The Memory Of Wolfgang Yourgrau


Following the ideas of Poincaré, Reichenbach, and Grunbaum concerning the convention of setting up clock systems, we analyze clock systems and light propagation within the framework of four-dimensional symmetry. It is possible to construct a new four-dimensional symmetry framework incorporatingcommon time: observers in different inertial frames of reference use one and the same clock system, which is located in any one of the frames. Consequently, simultaneity has a meaning independent of position and independent of frame of reference. A further consequence is that the two-way speeds of light alone are isotropic in any frame. By the choice of clock system there will be one frame in which the one-way speed of light is isotropic. This frame can be arbitrarily chosen. The difference between one-way speeds and two-way speeds of light signals is considered in detail.


Light Signal Inertial Frame Light Propagation Common Time Clock System 
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  1. 1.
    E. U. Condon and H. Odishaw, inHandbook of Physics (McGraw-Hill, 1967), pp. 6–158–6–165.Google Scholar
  2. 2.
    J. P. Hsu,Found. Phys. 6, 317 (1976);7, 953 (1977);8, 371 (1978).Google Scholar
  3. 3.
    C. B. Chiu, J. P. Hsu, and T. N. Sherry, CPT preprint 292.Google Scholar
  4. 4.
    H. Poincaré,Bull. Sci. Math. 28, 306 (1904);The Foundation of Science, (The Science Press, New York, 1921), pp. 303–313.Google Scholar
  5. 5.
    H. Reichenbach,The Philosophy of Space and Time (Dover, New York, 1958).Google Scholar
  6. 6.
    A. Grünbaum,Philosophical Problems of Space and Time (Reidel, Boston, 1973).Google Scholar
  7. 7.
    T. M. Kalotas and A. R. Lee,Found. Phys. 8, 603 (1978).Google Scholar
  8. 8.
    J. P. Hsu and T. N. Sherry,Found. Phys. 8, 609 (1978).Google Scholar
  9. 9.
    J. P. Hsu and J. A. Underwood,Found. Phys. 8, 833 (1978).Google Scholar
  10. 10.
    K. Brecher,Phys. Rev. Lett. 39, 1051 (1977).Google Scholar
  11. 11.
    J. A. Winnie,Phil. Sci. 37, 81, 223 (1970).Google Scholar

Copyright information

© Plenum Publishing Corporation 1980

Authors and Affiliations

  • J. P. Hsu
    • 1
  • T. N. Sherry
    • 2
  1. 1.Space Sciences LaboratoryNASA/Marshall Space Flight CenterHuntsville
  2. 2.International Center for Theoretical Physics, MiramareTriesteItaly

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