We can measure the expansion of the universe with velocities and distances of extragalactic objects. But measuring distances is tough! The authors of this paper have developed a new technique for measure the distances of AGN using the “echo” of light from heated dust.
This paper demonstrates a brand new method of calculating Hubble’s Constant using the luminosity of HII galaxies.
In everyday life, measuring distances is easy. In astronomy, however, accurate distance measurements are complicated by a whole host of factors. These authors are improving methods to determine the distance to small M Dwarf stars.