  One of the most dominant energy budget of the Universe is Dark Energy, which
remains enigmatic since the claim of its existence from the observation of
late-time cosmic acceleration. We propose a new way of inferring this by
measuring the aging of the Universe using only gravitational wave (GW) signals
from coalescing binary compact objects of any masses. We show that the aging of
the Universe will lead to a change in the observed chirp mass of the GW sources
inferred from different stages of its coalesces by monitoring a coherent source
from two far-apart GW frequencies for a few years. We show that coordinated GW
detectors which can reach a relative uncertainty on chirp mass measurement of
about $10^{-9}$, can measure a tiny departure of about $2\%$ from the dark
energy equation of state parameter $w_0=-1$ and its variation with cosmic time
by using stellar origin binary black holes up to redshift $z=5$ in 10 years of
observation time without using any external calibrator. If the next generation
of GW detectors can achieve this precision, then it can open a new window to
discover the fundamental nature of dark energy.
