Internet Archive. 2026Strip the empirical claim to what has actually been measured, and the inventory is short. Stars orbit something dark and very massive at the center of our galaxy; we have tracked S2's twenty-year ellipse around Sagittarius A* and can fit its motion to general relativity, within a few percentage points. X-ray binaries throughout the disk emit spectra consistent with accretion onto compact, gravitationally deep objects whose mass functions exceed any neutron-star upper limi
