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Proceedings Paper

Shapiro delay: a frequency dependent transit time effect, not a space time effect
Author(s): Shahin Ghazanshahi; Edward H. Dowdye
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Paper Abstract

Irvin L. Shapiro first noticed in 1964 that the transit time required for a microwave signal to propagate through space, arrive at a satellite orbiting Venus or Mercury and then return back to the earth by the sun to be received at the observatory, had a measurable time delay that varied as a function of the impact parameter of the microwave beam relative to the sun. The delays were observed to be in the order of 100's of microseconds when the impact parameter of the microwave beam was at a minimum. These measurements permitted a precise determination of the electron density profile of the solar wind as a function of the radial distance r from the sun. The electron density profile of the solar wind is found to behave very nearly as an inverse square of the radial distance r from the sun. The solar wind is found engulf the outmost planets of the solar system. The bulk of all the measurements were done using microwave frequencies from 500 MHz to 8.8MHz. Significant findings of this research reveal that, for all microwave signals propagating in the solar wind atmosphere of the solar system, the waves are subjected to a frequency dependent plasma index of refraction n that exceeds unity, i.e., n > 1.0. For optical, IR and UV wavelengths, the plasma index of refraction n is 1.0000000000 for these wavelengths which are virtually unaffected by the solar wind electron density. As a consequence of these findings, the Shapiro delay cannot be related to a space-time effect of General Relativity which is independent of frequency.

Paper Details

Date Published: 29 September 2011
PDF: 8 pages
Proc. SPIE 8121, The Nature of Light: What are Photons? IV, 81210A (29 September 2011); doi: 10.1117/12.906064
Show Author Affiliations
Shahin Ghazanshahi, California State Univ., Fullerton (United States)
Edward H. Dowdye, Pure Classical Physics Research (United States)


Published in SPIE Proceedings Vol. 8121:
The Nature of Light: What are Photons? IV
Chandrasekhar Roychoudhuri; Andrei Yu. Khrennikov; Al F. Kracklauer, Editor(s)

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