# Hubble slow motion

20 Feb 2013Does time pass slower in distant galaxies? If you could observe a planetary system at high redshift and observe the orbits of planets (or any other dynamical system driven by gravity), would the observation be consistent with a lower gravity instead of a slower passage of time? What about atomic processes like chemical reactions or radiative processes?

bonus question: Can you show that for a real-valued matrix \(A\) the matrix exponential \(\exp(A)\) transforms according to \(\exp(R^{-1}AR) = R^{-1}\exp(A)R\) with any invertible matrix \(R\)?