The observed apparent time dilation of supernovae light curves claimed
recently by Leibundgut et al. to establish directly the ''expansion o
f the universe'' is, rather, a general implication of fundamental phys
ics. In particular, it applies to chronometric cosmology, in which it
appears explicitly as a generalized Lorentz-Fitzgerald contraction. Th
e dilation effect was earlier shown in the proper motion-to-redshift r
elation of superluminal sources, as analyzed in the frame of chronomet
ric cosmology by Segal, providing an estimate of the cosmic distance s
cale.