The visible mass in the Universe emerged at the Big Bang when hadrons — the building blocks of atomic nuclei — formed from a hot fireball made of quarks and gluons reports Nature. When temperatures raise to trillions of degrees, particles deep inside the atoms start to shift into new, non-atomic states. Protons and neutrons inside the fireball of a neutron-star merger reach a density analogous to the effect of cramming New York City into a sugar cube.
Gravitational-wave researchers increasingly think that globular clusters, dazzling, celestial “snow globes” populated with hundreds of thousands of closely packed stars, harbor dark “hearts,” loaded with dozens to even hundreds of black holes–by far the greatest concentration of these exotic objects found anywhere in the universe.
On October 16, 2017, an international group of astronomers and physicists excitedly reported the first simultaneous detection of light and gravitational waves from the same source–a merger of two neutron stars. Now, a team that includes several University of Maryland astronomers has identified a direct relative of that historic event.
