Rapid growth of seed black holes in the early universe by supra-exponential accretion

Sheltered black hole seeds grow faster Astrophysicists have struggled to find a way to grow supermassive black holes within the first billion years of the universe, in the first 6% of its current age. These objects power the extremely bright and distant quasars whose light from that era has finally reached us. To grow a black hole so massive so quickly seemed to violate the expected balance of both radiation pressure and angular momentum. Alexander and Natarajan report that the predicted accretion rate can be exceeded with the help of a protective gas cloud at the heart of a star cluster. There, the radiation from accretion is reverted back onto the black hole, enabling a phase of supraexponential growth for a brief 10 million years. Science , this issue p. 1330