Cosmoboffins think grav waves hold the key to sorting out the disputed Hubble Constant
https://www.theregister.co.uk/2018/10/23/gravitational_waves_hubble_constant/
Scientists agree that the universe is expanding at an increasing rate, but by exactly how much is still an enigma.
To measure the pace of expansion, slightly confusingly known as Hubble’s Constant because it's not actually constant, boffins need two bits of information. One is the speed at which an object is receding from Earth due to the expansion of space time, and the other is its current distance.
Peak your interest for answers to this dark matter conundrum by reviewing an alternative theory of the universe from a more 4th dimensional perspective. This concept was previously approached in the book, 'The Evolutioning of Creation: Volume 2', copyrighted in 2011. As the predominant condition of the universe is a combination of dark energy and dark matter (i.e., massless matter or negative mass density), then the existence of our universe [or positive mass density] is more of an intrusion upon this norm. Such is it that positive density mass (i.e., baryonic mass) provides for a displacement effect, which is expressed as if the positive mass has intruded upon the inertial condition of the space-time continuum.
You can peak your interest for answers to this mystery from the perspective of the science fiction novel, 'Shadow-Forge Revelations'. As science fiction imitates science theory, this novel discusses how dark energy and dark matter interplays with the concept of the expanding universe from the inception of its creation.