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I am just writing up my MSc thesis and want to explain the dimensionless hubble parameter that I have been using through my work. I understand that you take the valuefor the Hubble "constant" and then divide by 100km/sec/Mpc to leave get a value which has no units. There seems to be surprisingly little literature on something that is so commonly used and fundamental a concept in cosmology. I just want to check that I am right in thinking this value is independent of time and position (hence dimensionless). Also I read in "Peebles: The large-scale Structure of the Universe 1981" that this dimensionless value also reflects the uncertainty in H. I cant see how. Can anyone explain? Also why do we use units of h^2 sometimes and h^-1 at other times? Your help is most appreciated.

Cheers

Taylrl

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# Some slight confusion regarding the dimensionless Hubble parameter h.

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