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.