The running is potentially a key cosmological variable – it is small, but unlike the tensor-scalar ratio it is unlikely to be so small as to be forever undetectable and we are thinking about how to maximise the effectiveness of future cosmological experiments to make the most of this opportunity. 

Exploring the galactic gravitational field directly by precision measurements of stellar velocities.

A recent paper made the somewhat surprising claim that black holes in an expanding universe are "cosmologically coupled" -- that is, their mass increases as the Universe expands, to the point that the density of a population of black holes would stay constant as the...

If the visible universe starts out at the Planck scale it must have grown larger by at least 60 factors of 10 since the Big Bang. Half of these "decades" of expansion would be accounted for by the hypothetical inflationary phase, a period of accelerated growth that...