Unless I'm now out-of-date, it is the first time a system quite like this has been observed. Quiet star quietly orbiting in a black-hole binary. Furthermore, it

Unless I'm now out-of-date, it is the first time a system quite like this has been observed. Quiet star quietly orbiting in a black-hole binary. Furthermore, it is very close to us on cosmological scales -- in our own galaxy, just over 1% of a galactic-diameter distant. From this observation alone, one can directly sharpen up models not only of the probable number of BH-star binaries in the galaxy, but also models of the number of lonely black holes in the galaxy. Forty years ago, this might have been a Nobel-winning discovery, as it would have provided new and compelling evidence for the existence of black holes (the dark partner can't be a neutron star because it is far too heavy). That story is now familiar to astrophysicists from many angles. This discovery is still one of the early remarkable results from Gaia -- that dataset is going to continue to shape our understanding of our neighborhood and our universe for decades to come. It's very cool.