Mysterious X-rays could be kilonova “afterglow” from 2017 neutron star merger This would mean the two stars "spun down" for a second before collapsing into black hole.

Cosmic Afterglow Revelation May 'Rewrite the History of the Universe' Published May 13, 2025 at 11:24 AM EDT Updated May 14, 2025 at 5:58 AM EDT. By .