Abstract
In this methodological note we discuss several topics related to
interpretation of some basic cosmological principles. We demonstrate that one
of the key points is the usage of synchronous reference frames. The
Friedmann-Robertson-Walker one is the most known example of them. We describe
how different quantities behave in this frame. Special attention is paid to
potentially observable parameters. We discuss different variants for choosing
measures of velocity and acceleration representing the Hubble flow, and present
illustrative calculations of apparent acceleration in flat $Łambda CDM$ model
for various epochs. We generalize description of the "tethered" galaxies
problem for different velocity measures and equations of state, and illustrate
time behavior of velocities and redshifts in the $Łambda CDM$ model.
Users
Please
log in to take part in the discussion (add own reviews or comments).