A neutron star is the ultra-dense remnant of a massive star's supernova explosion, composed almost entirely of neutrons and supported by neutron degeneracy pressure. These extraordinary objects represent one of the most extreme states of matter in the universe, packing 1.4 times the Sun's mass into a sphere merely 20 kilometers across—imagine cramming Mount Everest into a teaspoon.</p><p>When stars 8-25 times more massive than our Sun exhaust their nuclear fuel, gravity overwhelms all other forces, crushing protons and electrons together to form neutrons. This creates a cosmic lighthouse with a magnetic field trillion times stronger than Earth's, spinning up to 700 times per second while beaming radiation from its magnetic poles.</p><p>Neutron stars were first theorized in 1934 by astronomers Walter Baade and Fritz Zwicky, but remained hypothetical until 1967 when Jocelyn Bell Burnell discovered pulsars—rapidly spinning neutron stars whose beams sweep across Earth like cosmic metronomes. The famous Crab Pulsar, born from a supernova witnessed by Chinese astronomers in 1054 CE, rotates 30 times per second and serves as one of the most precise natural clocks in the universe.</p><p>These stellar corpses have revolutionized our understanding of extreme physics, providing natural laboratories for studying matter under conditions impossible to recreate on Earth, and recently enabled the detection of gravitational waves when pairs collide.