DARK ENERGY AND THE EXPANDING UNIVERSE

New measurements of the rate of expansion of the early universe indicate a slower expansion rate than expected.

http://www.bbc.co.uk/news/science-environment-26329320

The BOSS measurements were carried out using a 2.5 m telescope in New Mexico. While measurements of more recent expansion agree well with expected values, the early measurements around three billion years after the big bang give a slower rate than predicted.

BOSS team scientists at Portsmouth University say if further measurements with bigger samples confirm these findings, this may be an indication that the dark energy linked to the universe expansion is not a constant value  as assumed, but varies in some way.