why can the equation of state $w$ of dark energy in a scalar field model never be larger than $+1$ and never be more negative than $-1$? are there physical arguments why this would be weird? what would happen to distance measures and to structure growth if $w$ were outside this range?
bonus question: does the Higgs-mechanism in quantum field theory give rise to mass or to inertia?
second bonus question: why is dark matter called dark matter if it does not interact with light? if that was the reason, it should rather be called transparent matter, don't you agree?