The Rarest Things In The Universe Explained In 16 Minutes

eutron Star Collisions. A neutron star is the collapsed core of a massive star, a sphere roughly 12 to 15 miles across containing more mass than the Sun. The matter inside is packed so tightly that a single teaspoon of it would weigh billions of tons. The core is what remains after a star far larger than the Sun exhausts its fuel and its own gravity crushes it inward, compressing its protons and electrons together into a solid mass of neutrons. On rare occasions, two of these objects form as a pair and orbit each other in a slowly decaying spiral, drawing closer over millions of years. As they circle, they radiate away energy in the form of gravitational waves, ripples in spacetime itself, and this loss causes the orbit to tighten. The two stars accelerate as the gap between them shrinks, until they finally merge. The event lasts less than a second. In that instant, temperatures and pressures reach a level found nowhere else in the modern universe. The collision forges heavy elements that ordinary stars cannot produce, because the process requires a flood of neutrons so dense that it exists only in this moment of impact.