9. When Lambda is included in Friedmann's equation it enters the RHS as a term Lambda/3, hence Lambda has the same units as H² - i.e. time^-2.

When the Lambda term is dominant, it drives an exponential expansion of the universe with a(t) scaling as exp(t/sqrt(3/Lambda)) - see RR(8.2) - hence 1/sqrt(Lambda) is approximately the timescale on which the cosmological constant causes the universe to expand.

The contribution of a cosmological constant to Omega is Omega_Lambda=Lambda/(3H²), where H is the Hubble parameter. So, for Omega_Lambda=0.7 and H=70 km/s/Mpc, we find that Lambda=1.1x10^-35 s^-2, from which 1/sqrt(Lambda)=9.6x10⁹ yr. This is comparable to the age of the Universe, of course. What is the implication of this?