Cosmology2026-01-061 minarXiv:2601.03347expressBlack Holes 'Weigh' the Expansion Rate of the UniverseEach merger of black holes produces gravitational waves — ripples in the fabric of the universe — predicted by Einstein and first detected with key contributions from Kip Thorne.Matteo Tagliazucchi·Michele Moresco·Nicola Borghi·Chiara CiapettiFirst law of black hole mechanicsHubble's lawJacob BekensteinStephen HawkingAdam Riessblack hole mergergravitational wavesblack holegamma-ray burstgravitational singularity👍👎☆SimplePopularAdvanced