Death spiral: A black hole spins on its side

Experiences of racism in adolescence raise risk of depression for Black women

The two colossal black holes, 9 billion light-years from Earth, orbit each other once every two years and will have a highly energetic collision when they meet.

The axis of rotation of a black hole in a binary system is tilted more than 40 degrees relative to the axis of the stellar orbit. Scientists have often assumed this difference to be very small and the finding challenges current theoretical models of black hole formation.