Summary: Is the velocity of light a fixed constant of nature, invariant over time? This page presents the available measurements of c and several statistical studies which suggest that c has decreased in the past 300 years. What other "constants" of physics might prove to be non-fixed? How would a non-constant c affect physical laws? Possible consequences for cosmology and the age of the universe. Responses and comments are solicited.

Of Special Interest

  • A Brief History of c
  • Implications of Changing Constants: collected notes and questions.
  • Is the Universe Static or Expanding? by Barry Setterfield (8/23/02)
  • Upheaval in Physics: History of the Light-Speed Debate, Helen Setterfield
  • Recent Lightspeed Publicity, by Barry Setterfield (Nature, Paul Davies)
  • A Layman's Guide to the CDK Debate, by Malcolm Bowden
  • A Simplified Explanation of the Setterfield Hypothesis, by Helen Fryman with Barry Setterfield
  • Reports of the Death of Speed of Light Decay are Premature, by Malcolm Bowden (April 1998, CENTJ article)
  • The Vacuum, Light Speed and the Redshift, by Barry Setterfield | PDF version (6/21/01)
  • Your email comments and questions for Barry Setterfield are welcome,

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