  While observational cosmology has shown tremendous growth over the last
decade, deep mysteries continue to haunt our theoretical understanding of the
ingredients of the concordance cosmological model, which are mainly `dark'.
More than 95 percent of the content of the energy-stress tensor has to be in
the form of inflaton, dark matter and dark energy, which do not have any
non-gravitational or laboratory evidence and remain unidentified. Moreover, the
dark energy poses a serious confrontation between fundamental physics and
cosmology. This makes a strong case to discover alternative theories which do
not require the dark sectors of the standard approach to explain the
observations.
  In the present situation, it would be important to gain insight about the
requirements of the `would be' final theory from all possible means. In this
context, the present paper highlights some, hitherto unnoticed, interesting
coincidences which may prove useful to develop insight about the `holy grail'
of gravitation. It appears that the requirement of the speculative dark sectors
by the energy-stress tensor, is indicative of a possible way out of the present
crisis appearing in the standard cosmology, in terms of a theory wherein the
energy-stress tensor does not play a direct role in the dynamics. It is shown
that various cosmological observations can be explained satisfactorily in the
framework of one such theory $-$ the Milne model, without requiring the dark
sectors of the standard approach. Moreover, the model evades the horizon,
flatness and the cosmological constant problems afflicting the standard
cosmology.
  Though Milne's theory is an incomplete, phenomenological theory, and cannot
be the final theory of gravitation, nevertheless, it would be worthwhile to
study these coincidences, which may help us develop insight about the would-be
final theory.
