The 'stickiness' inside colliding stars might be a literal window into a hidden phase change that happened right after the Big Bang.
March 17, 2026
Original Paper
Critical slowing down and bulk viscosity in binary neutron star mergers
arXiv · 2603.13474
The Takeaway
When neutron stars merge, they create a 'quark soup' so dense it mimics the early universe. This paper shows that as this soup changes states, it becomes extremely viscous, potentially causing a 'stutter' in gravitational waves that would let us see a hidden state of matter.
From the abstract
Hydrodynamic simulations of neutron star mergers rely on the clear separation between the strong-interaction, weak-interaction, and hydrodynamic timescales. In this effective framework, weak Urca interactions are typically the slowest microscopic processes, and therefore the Urca rate determines the bulk-viscous dissipation. This assumed hierarchy of dissipative mechanisms can be decisively altered, without invalidating hydrodynamics, if the trajectory of the matter in a neutron star merger pass