The Thomas Townsend Brown Family Website

May 2, 1980

Dr. T. Townsend Brown
Department of Physics and Astronomy
University of North Carolina at Chapel Hill
Phillips Hall 039 A
Chapel Hill, North Carolina 27514

Dear Dr. Brown,

This replies to your letter of March 18 concerning the possible role of optical-frequency gravitational waves in your experiments.

I must confess that I do not understand the details of your experiment. I have no prior familiarity with any experiments in dielectric absorption or with electrets. In order to fully understand your ideas I would have to read a description of the details of the experiment.

However, even without such description, I can say with near certainty that gravitational waves cannot possibly be the cause of the effects which you see. This is because of the exceedingly weak coupling between gravitational waves and matter. For example, if the energy flux of cosmic electromagnetic radiation from the sun on the Earth were equal to the flux of electromagnetic radiation from the sun on the Earth, and if those waves were at optical frequencies as you propose, then those waves would produce oscillatory displacements of electrons in atoms (in a semi-classical description) of magnitude roughly 10^-38 centimeters.

You have in Chapel Hill one of the world's best experts in general relativity theory: Professor James York. I suggest that you discuss your ideas with him.

Sincerely,

K. T.
Professor of Theoretical Physics