This article focuses on the influence of Dark Energy on the expansion of the Universe. Very little is known about this property of space, but what has been discovered is that the Universe is undergoing an accelerating expansion, contrary to our former belief that the universe was expanding at a decelerating (pardon the incorrect terminology) rate due to gravitational forces. This drastic shift in theory emerged as a result of the realization that space possesses its own energy, dark energy, whose repulsive force is responsible for the increasing rate of expansion that has been observed through two key techniques. One method of analysis involves baryon acoustic-oscillations, which provide a preferred scale for analyzing the separation of galaxies. The second method involves "redshift space distortions", which has thus far provided results consistent with Einsteins theory of general relativity in conjunction with his cosmological constant. As I stated earlier, our understanding of dark energy and its counterpart dark matter is incredibly limited. However, through further experimentation, the mysterious matter that comprises approximately 70% of the Universe, may become a more tangible concept and open up the scientific world to new principles in physics.
http://www.bbc.co.uk/news/science-environment-17559286