Skip to main content

Observational evidences for the speed of the gravity based on the Earth tide


We have found that the current practical Newtonian formula for the gravity tide of the Earth implies a hypothesis that gravity travels at the speed of light; furthermore, we have derived and solved the propagation equation of gravity using the observation data of Earth tides from Shiquanhe and Wushi, after correction of phase lag due to the anelasticity of the Earth, and found that the speeds of gravity are from 0.93 to 1.05 times the speed of light with a relative error of about 5%. This provides first set of strong evidences to show that the speed of gravity is the same as the speed of light.


  1. Einstein A. The Meaning of Relativity. 5th ed. Princeton, NJ: Princeton University Press, 1954

    Google Scholar 

  2. Hartle J B. Gravity: An Introduction to Einstein’s General Relativity. San Francisco: Addison Wesley, 2008

    Google Scholar 

  3. Ohanian H C. Gravitation and Spacetime. New York: W.W. Norton & Company, Inc. 1976

    Google Scholar 

  4. Ohanian H C, Ruffini R. Translated by Xiang S P, Feng L L. Gravitation and Spacetime (in Chinese). Beijing: Science Press, 2006

    Google Scholar 

  5. Melchior P. The Tides of Planet Earth. New York: Pergamon Press, 1978

    Google Scholar 

  6. Agnew D C. Earth tides. In: Herring T, ed. Treatise on Geophysics. Oxford: Elsevier, 2007. 163–195

    Chapter  Google Scholar 

  7. Tang K Y, Zhang H, Wang Q, et al. Gravity effects of solar eclipse and inducted gravitational field. In: American Geophysical Union, Fall Meeting 2003, abstract #G32A-0735

    Google Scholar 

  8. Tang K Y. The retarded gravitation and paleogravity. In: 27th General Assembly of International Astronomy Union, Rio de Janeiro, Brazil, 2009. 44–45

    Google Scholar 

  9. Tang K Y. Total solar eclipse and the pendulum challenging Einstein. Chin Natl Astron, 2009, 11: 40–45

    Google Scholar 

  10. Tang K Y. Observational evidences on the speed of gravity (in Chinese). In: Report in the Annul Meeting for the Commission of Gravity and Relativistic Astrophysics of Chinese Society of Physics, Shijiazhuang, China, 2010

    Google Scholar 

  11. Tang K Y. Observational evidences to show that gravitational field travels at the speed of light. In: 2010 International Workshop on Gravitational Waves Detection with Atom Interferometer, Hangzhou, China, 2010

    Google Scholar 

  12. Tang K Y, Wen W, Hua C C, et al. Observational evidences for the propagation speed of gravity. In: 28th General Assembly of International Astronomy Union, Beijing, China, 2012. 938–939

    Google Scholar 

  13. Ray R D, Eanes R J, Chao B F. Detection of tidal dissipation in the solid Earth by satellite tracking and altimetry. Nature, 1996, 381: 595–597

    Article  Google Scholar 

  14. Ray R D, Eanes R J, Lemoine F G. Constraints on energy dissipation in the Earth’s body tide from satellite tracking and altimetry. Geophys J Int, 2001, 144: 471–480

    Article  Google Scholar 

  15. Arabelos D. Comparison of Earth-tide parameters over a large latitude difference. Geophys J Int, 2002, 151: 950–956

    Article  Google Scholar 

  16. Xu J Q, Sun H P, Zhou J C. Experimental detection of the inner core translational triplet. Chin Sci Bull, 2010, 55: 276–283

    Article  Google Scholar 

  17. Xu J Q, Chen X D, Zhou J C, et al. Characteristics of tidal gravity changes in Lhasa, Tibet, China. Chin Sci Bull, 2012, 57: 2586–2594

    Article  Google Scholar 

Download references

Author information

Authors and Affiliations


Corresponding author

Correspondence to KeYun Tang.

Additional information

This article is published with open access at

Rights and permissions

This article is published under an open access license. Please check the 'Copyright Information' section either on this page or in the PDF for details of this license and what re-use is permitted. If your intended use exceeds what is permitted by the license or if you are unable to locate the licence and re-use information, please contact the Rights and Permissions team.

About this article

Cite this article

Tang, K., Hua, C., Wen, W. et al. Observational evidences for the speed of the gravity based on the Earth tide. Chin. Sci. Bull. 58, 474–477 (2013).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:


  • Earth tide
  • apparent position
  • phase lag
  • speed of light
  • speed of gravity
  • propagation equation of gravity