Observing Quanta on a Cosmic Scale
  Our entire galaxy, like all others, originated as a fairly smooth patch of binding energy, which in turn originated as a single quantum perturbation of the inflaton field on a subatomic scale during inflation. The best preserved relic of these perturbations is the anisotropy of the microwave background radiation, which on the largest scales preserves a faithful image of the primordial quantum fields. It is possible that close study of these perturbations might reveal signs of discreteness caused by spacetime quantization. 
Craig J. Hogan