Dynamic horizons rewrite black hole thermodynamics

A Penn State team led by Abhay Ashtekar proposes replacing Hawking's equilibrium-based event horizon with a 'dynamical horizon' and generalizing black hole thermodynamics to non-equilibrium situations, allowing the first and second laws to apply during growth, mergers, and evaporation. This framework complements Hawking radiation by focusing on entropy changes in dynamical processes, improving our understanding of evolving black holes; the work is published in Physical Review Letters.