Neutron-degenerate matter

Neutron degenerate matter is a state of matter found in neutron stars, which are the densest objects in the universe(besides maybe black holes). It consists primarily of neutrons and forms under extreme pressure and density, conditions that do not naturally occur on Earth. In neutron degenerate matter, the Pauli exclusion principle plays a role, it prevents similar fermions (neutrons) from occupying the same quantum state. This results in a state where all the lower energy levels are filled, creating a form of matter that is very highly resistant to compression.

The density of neutron degenerate matter is immense; a teaspoon of it would weigh around 1,000,000,000 tons. This state of matter is created during the formation of a neutron star, where protons and electrons combine to form neutrons, releasing neutrinos in the process. This transformation occurs in the aftermath of a supernova, end of a massive star's life, when the core's mass is within the range of roughly 1.4 to 3 solar masses.

Neutron degenerate matter is a opportunity to study the properties of matter under extreme conditions, challenging our understanding of fundamental physics.