The discovery came after NASA's team pioneered new measurement techniques that they claim give the findings an "unprecedented" level of accuracy. Cosmologists typically measure astronomic distances using light, specifically changes in redshift. These measurements (and those before it) are used to estimate the rate of the universe's expansion, known as the Hubble constant. NASA and the ESA's new data put this rate of expansion at 45.5 miles per second per megaparsec -- a few percent faster than the two most recent missions.
Adam Reiss, the study leader and Nobel Laureate, explains that not only does this suggest the universe is expanding more rapidly, but the new findings could provide clues about what makes up the parts of the universe we currently struggle to understand -- the elusive dark matter, dark energy and dark radiation.
The current theories as to why the universe is expanding faster are that dark energy or dark matter's role in the universe is misunderstood, there's another subatomic particle we don't yet know about or that Einstein's theory of gravity is incomplete.