Black Holes Slowed Their Feeding

A Chandra X‑ray analysis (published in The Astrophysical Journal, Dec 2025) compared three hypotheses for why supermassive black holes grow less today and concluded the primary cause is a drop in accretion efficiency — black holes are simply consuming surrounding matter more slowly as the universe ages. The result comes from X‑ray observations spanning billions of years and implies the slowdown will continue into the future. — This shifts the explanation for declining black‑hole and galaxy growth from population or mass changes to a physical change in feeding efficiency, changing the targets for theory, simulation, and future observatories.