  We investigate the variation of the gravitational constant $G$ over the
history of the Universe by modeling the effects on the evolution and
asteroseismology of the low-mass star KIC 7970740, which is one of the oldest
(~11 Gyr) and best-observed solar-like oscillators in the Galaxy. From these
data we find $\dot{G}/G = (1.2 \pm 2.6) \times 10^{-12}~\text{yr}^{-1}$, that
is, no evidence for any variation in $G$. We also find a Bayesian asteroseismic
estimate of the age of the Universe as well as astrophysical S-factors for five
nuclear reactions obtained through a 12-dimensional stellar evolution Markov
chain Monte Carlo simulation.
