  The absolute distance scale measurements in cosmology have always been an
important mission. In particular, in recent years, the Hubble constant tension
between the measurements from early and late universe has become a new crisis
for cosmology, which calls for new, independent absolute cosmological distance
measurements. Recently, a result of measuring the parallax distance to 3C 273
through spectroastrometry and reverberation mapping was reported. We comment on
this novel method in this News & Views paper.
