Letter | Published:

Equation of Motion in Five Space

Naturevolume 192page1320 (1961) | Download Citation



THERE exist many models for the description of the gravitational and electromagnetic field. Perhaps the most successful formalism developed is still that of Kaluza1, with notable improvements by Bergmann2 since it reproduces exactly the classic equations of the electromagnetic field with gravity. However, there still remained the well-known difficulties associated with the classic treatment of Nature so that generalizations which lead to substantially different equations were made in the hope that there could be included within the new frameworks an adequate theory encompassing quantum-phenomena as well. These hopes have not been realized; but nevertheless it is most difficult to relinquish a theory which by and large has been subject to confirmation—quite strikingly in recent times using techniques based on the Mössbauer effect3. In addition to numerous verifications of the original version of the theory, Einstein, Infeld and Hoffmann4 have shown that there exists a most æsthetic feature, namely, that the field equations themselves determine the classic equations of motion of ‘singularities’ or ‘particles’ in the field. Thus it is not necessary to supplement the field equations with ponderomotive equations.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.


  1. 1

    Kaluza, T., S. B. preuss. Akad. Wiss., 966 (1921).

  2. 2

    Bergmann, P. G., An Introduction to the Theory of Relativity (New York, 1942).

  3. 3

    Pound, R. V., and Rekba, jun., G. A., Phys. Rev. Letters, 3, 439 (1959). Hay, H. J., Shiffer, J. P., Cranshaw, T. E., and Egelstaff, P. A., ibid., 4, 165 (1960). Sherwin, C. W., Phys. Rev., 120, 17 (1960).

  4. 4

    Einstein, A., Infeld, L., and Hoffmann, B., Ann. Math., 39, 65 (1938). Einstein, A., and Infeld, L., ibid., 41 (1940).

Download references

Author information


  1. University of Hawaii, Honolulu



  1. Search for CHRISTOPHER GREGORY in:

About this article

Publication history

Issue Date



Further reading


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.