  Dwarf novae are white dwarfs accreting matter from a nearby red dwarf
companion. Their regular outbursts are explained by a thermal-viscous
instability in the accretion disc, described by the disc instability model that
has since been successfully extended to other accreting systems. However, the
prototypical dwarf nova, SS Cygni, presents a major challenge to our
understanding of accretion disc theory. At the distance of 159 +/- 12 pc
measured by the Hubble Space Telescope, it is too luminous to be undergoing the
observed regular outbursts. Using very long baseline interferometric radio
observations, we report an accurate, model-independent distance to SS Cygni
that places the source significantly closer at 114 +/- 2 pc. This reconciles
the source behavior with our understanding of accretion disc theory in
accreting compact objects.
