  The observed value of the cosmological constant corresponds to a time scale
that is very close to the current conformal age of the universe. Here we show
that this is not a coincidence but is caused by a periodic boundary condition,
which only manifests itself when the metric is represented in Euclidian
spacetime. The circular property of the metric in Euclidian spacetime becomes
an exponential evolution (de Sitter or $\Lambda$ term) in ordinary spacetime.
The value of $\Lambda$ then gets uniquely linked to the period in Euclidian
conformal time, which corresponds to the conformal age of the universe. Without
the use of any free model parameters we predict the value of the dimensionless
parameter $\Omega_\Lambda$ to be 67.2 %, which is within $2\sigma$ of the value
derived from CMB observations.
