  Padmanabhan found a definition for the surface density of space time degrees
of freedom. We prove that this density can be constructed from a phase space
which is derived with respect to a special space like vector field. This vector
field is the direction of an accelerating vector field. After projecting this
phase space along a velocity vector field, we show that Padmanabhan's surface
density is actually the projected phase space during one period of the
Euclidean time which is expected for a canonical ensemble. This suggests that
Padmanabhan's density should be regarded as a spatial phase space which is
driven by acceleration.
