  Cosmological constant problem (in its various versions) is arguably the
deepest gap in our understanding of theoretical physics, the solution to which
may very likely require revisiting the Einstein theory of gravity. In this
letter, I argue that the simplest consistent way to decouple gravity from the
vacuum energy (and hence solve the problem) is through the introduction of an
incompressible gravitational aether fluid. The theory then predicts that
gravitational constant for radiation is 33% larger than that of
non-relativistic matter, which is preferred by most cosmological observations
(with the exception of light element abundances), but is not probed by current
precision tests of gravity. I also show that slow-roll inflation can happen in
this theory, with only minor modifications. Finally, interpreting gravitational
aether as a thermodynamic description of gravity, I propose a
finite-temperature correction to the equation of state of gravity, which would
explain the present-day acceleration of the cosmic expansion as a consequence
of the formation of stellar mass black holes.
