Astrophysics and Space Science

, Volume 17, Issue 1, pp 223–237 | Cite as

Precision measurement of the Sun's gravitational field by means of the twin probe method

  • Bruno Bertotti
  • Giuseppe Colombo


An accurate measurement of the gravitational field of the Sun, needed for the verification of the theories of gravitation, requires the use of a geodesic test body. To eliminate the effect of non-gravitational forces (mainly the solar radiation pressure) we propose to use two twin space probes, whose surface has identical geometrical and optical properties, but with different mass. Their differential motion leads to the determination of the motion of an ideal geodesic point. We discuss in detail the various conditions which are needed to ensure the required degree of identity and submit as a possible solution two cylindrical probes, whose sides are covered by ‘cavities’ to make them absorbing, rotating at a fast rate around an axis orthogonal to the ecliptic plane. We discuss briefly also the accuracy in the determination of the parameters of the metric field of the Sun obtainable from range measurements.


Optical Property Solar Radiation Fast Rate Space Probe Gravitational Field 
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Copyright information

© D. Reidel Publishing Company 1972

Authors and Affiliations

  • Bruno Bertotti
    • 1
  • Giuseppe Colombo
    • 2
  1. 1.Instituto di FisicaUniversità di PaviaItaly
  2. 2.Instituto di Meccanica Applicata alle MacchineUniversità di PadovaItaly

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