The dimensionless Hubble parameter, usually noted h, is obtained by dividing the Hubble parameter by a standard value, usually H₀ = 100 km·s⁻¹·Mpc⁻¹ Hubbles law is the statement in astronomy that the redshift in light coming from distant galaxies is proportional to their distance. ... km redirects here. ... Look up second in Wiktionary, the free dictionary. ... The megaparsec (abbreviated Mpc) is a unit of distance used in astronomy, equal to one million parsecs. ...