  WASP-12b stands out among the planets of its class of hot Jupiters because of
the observed fast orbital decay attributed to tidal dissipation. The measured
rate of the orbital period is $\stackrel{\bf\centerdot}{\textstyle{P}}_{\rm
orb}\,=\,-\,29\pm3\;\mbox{ms/yr}\;$=$\;(9.2\pm1.0)\times10^{-10}\;\mbox{s/s}$.
In the literature heretofore, all attempts to explain this high rate were based
on the assumption that the orbital evolution is dominated by the tides in the
star. Since the modified tidal quality factor in yellow dwarfs is insufficient
to warrant such a decay rate, a hypothesis was put forward that the star may
actually be a subgiant. Using the latest data from the Gaia mission, we deduce
that WASP-12a at $1.36\,{M_{Sun}}$ is an evolving dwarf at an early stage of
post-turn-off evolution that has not yet depleted hydrogen in its core. Its
unremarkable position in the color-magnitude diagram and the existence of close
planets orbiting red giants of similar mass contradict the hypothesis of an
abrupt boost of tidal quality due to structural internal changes. On the other
hand, the previous research neglected the tidal dissipation in the planet
assuming it to be negligible due to the likely synchronisation of its rotation
and a presumed high quality factor. We critically reassess this assumption in
the light of recent astrometric results for Jupiter and Saturn. Assuming that
the structure of WASP-12b is similar to that of our Jupiter and Saturn, we find
that the observed orbital decay is well explained by the tides in the planet.
The estimated value of the planet's modified quality factor coincides almost
precisely with that of our Jupiter.
