The Star That Survived

A sugar cube's worth of it weighs as much as a mountain. Here is what that sugar cube is made of: a star. Not the memory of a star, not the ghost of one — an actual star, squeezed until every atom inside it was crushed into its own bones. When a star far larger than our Sun runs out of fuel, it doesn't simply go out. It falls inward in a single second — faster than you can say the word — and the shockwave of that collapse blows the outer layers into a bloom of light so bright you can sometimes see it in the daytime sky. People have. They stood in fields, thousands of years ago, and watched a new star appear where nothing had been the night before, and didn't know they were watching something die. What's left behind is called a neutron star. It is roughly the width of a city. It spins, sometimes, hundreds of times per second — a dead star rotating faster than a kitchen blender — and as it spins, it sweeps a beam of radio waves across the galaxy like a lighthouse no one built. We only found them because those beams reached us. For a few weeks in 1967, the scientists who first detected the pulses thought they might be a signal. They labelled the source LGM-1. Little Green Men.