What are neutron stars and how are they formed?
Neutron stars are city-sized objects formed when stars weighing 4-8 solar masses explode leaving a dense core that continues to collapse forcing protons and electrons to combine and form neutrons, yielding the name "neutron stars". The rapidly rotating stars hold 1-3 solar masses in a 20-km diameter, with a "teaspoon" of their material weighing about a billion tonnes on Earth.