  The non-Keplerian galactic rotational curves and the gravitational lensing
data strongly indicate a significant dark matter component in the universe.
Moreover, these data can be combined to deduce the equation of state of dark
matter. Yet, the existence of dark matter has been challenged following the
tradition of critical scientific spirit. In the process, the theory of general
relativity itself has been questioned and various modified theories of
gravitation have been proposed. Within the framework of the Einsteinian general
relativity, here I make the observation that if the universe is described by a
spatially flat Friedmann-Robertson-Walker cosmology with Einsteinian
cosmological constant then the resulting cosmology predicts a significant dark
matter component in the universe. The phenomenologically motivated existence
proof refrains from invoking the data on galactic rotational curves and
gravitational lensing, but uses as input the age of the universe as deciphered
from studies on globular clusters.
