Abstract: The standard model of cosmology is based on the
Friedmann-Robertson-Walker (FRW) metric. Often written in
terms of co-moving coordinates, this elegant and highly
practical solution to Einstein's equations is based on the
Cosmological principal and Weyl's postulate. But not all
of the physics behind such symmetries has yet been
recognized. We invoke the fact that the co-moving frame
also happens to be in free fall to demonstrate that the
FRW metric is valid only for a medium with zero active
mass. In other words, the application of FRW appears to
require an equation-of-state rho+3p = 0, in terms of the
total energy density rho and total pressure p. Though the
standard model is not framed in these terms, the
optimization of its parameters brings it ever closer to
this constraint as the precision of the observations
continues to improve.
UNLV Physics & Astronomy Forum is held in the conference room of the Bigelow Physics Building, BPB-217 at 3:45PM. Refreshments at 3:30.
