Example sub-questions:

  • Was the speed of light always that value?
  • Was the acceleration due to gravity always been 9.8m/s/s?
  • Etc

By "change" I mean both actual change in the physical world because of multiple factors and "change" in the numerical value (because the initial value discovered was not precise or accurate).


Look to large redshift values with the Hubble telescope. Then do spectroscopy. Primary physical constants have not changed within visible time within experimental error - more than 14 significant figures for the hydrogen atom hyperfine transition. Look up the half-life of that spin flip, then Heisenberg for slop in the gears.

Terrestrial acceleration due to gravity is not a constant,


Big G is a universal constant. It is the worst-measured physical constant, upon which all gravitation hinges. Even worse, the very modest accuracy values substantially diverge - and don't grow better over the years,



Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.