Close-orbiting black hole pairs with near-equal masses M≈m are a new kind of macroscopic quantum object because they have inherent mass-uncertainty ΔM_total>(M+m)/380. That makes them the largest and heaviest macroscopic quantum systems ever found, the first observable physical system plausibly requiring quantum gravity for an accurate description, and the first which plausibly will enable learning about quantum gravity via direct observation. Lengths and times measured in the vicinity also should have relative uncertainties⪆1/380. To show that, we combine (1) rigorous forms of the energy-time uncertainty principle with (2) graviton-emission rate estimates – large rates force high mass-uncertainties ΔM; and more gravitons are emitted during 1 hour of super-super hole tight orbiting than the total count of non-graviton particles in the observable universe.

Perhaps you think it crazy anything that huge can have this large inherent mass, length, or time uncertainties. If so, then you interpret this as a paradox or crisis which needs resolution via adding some extra ingredient to today's laws of physics. The penultimate section, added for the third draft, proposes as that extra ingredient: the ΔEΔt uncertainty relations lose their validity when ΔE exceeds order 1 in Planck units, and explains how that is predicted by the author's "Cloud QFT" theory. The final section,added for the fourth draft, covers the "Copenhagen controversy" and related data analysis, which I wish the LIGO team would publicly perform every time instead of ignoring.