  We explore a new paradigm to study dissipative dark matter models using
gravitational-wave observations. We consider a dark atomic model which predicts
the formation of binary black holes such as GW190425 while obeying constraints
from large-scale structure, and improving on the missing satellite problem.
Using LIGO and Virgo gravitational-wave data from 12th September 2015 to 1st
October 2019, we show that interpreting GW190425 as a dark matter black-hole
binary limits the Chandrasekhar mass for dark matter to be below 1.4 $M_\odot$
at $> 99.9\%$ confidence implying that the dark proton is heavier than 0.95
GeV, while also suggesting that the molecular energy-level spacing of dark
molecules lies near $10^{-3}$ eV and constraining the cooling rate of dark
matter at low temperatures.
