  The source of the acceleration of the expansion of the Universe is still
unknown. We examine some consequences of the possible scale invariance of the
empty space at large scales. The central hypothesis of this work is that, at
macroscopic and large scales where General Relativity may be applied, the empty
space in the sense it is used in the Minkowski metric, is also scale invariant.
It is shown that if this applies, the Einstein cosmological constant and the
scale factor of the scale invariant framework are related by two differential
equations.
